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Sample records for biomimetic hydroxyapatite nanocrystals

  1. Biological activity of lactoferrin-functionalized biomimetic hydroxyapatite nanocrystals

    Directory of Open Access Journals (Sweden)

    Nocerino N

    2014-03-01

    Full Text Available Nunzia Nocerino,1 Andrea Fulgione,1 Marco Iannaccone,1 Laura Tomasetta,1 Flora Ianniello,1 Francesca Martora,1 Marco Lelli,2 Norberto Roveri,2 Federico Capuano,3 Rosanna Capparelli1 1Department of Agriculture Special Biotechnology Center Federico II, CeBIOTEC Biotechnology, University of Naples Federico II, Naples, 2Department of Chemistry, G Ciamician, Alma Mater Studiorum, University of Bologna, Bologna, 3Department of Food Inspection IZS ME, Naples, Italy Abstract: The emergence of bacterial strains resistant to antibiotics is a general public health problem. Progress in developing new molecules with antimicrobial properties has been made. In this study, we evaluated the biological activity of a hybrid nanocomposite composed of synthetic biomimetic hydroxyapatite surface-functionalized by lactoferrin (LF-HA. We evaluated the antimicrobial, anti-inflammatory, and antioxidant properties of LF-HA and found that the composite was active against both Gram-positive and Gram-negative bacteria, and that it modulated proinflammatory and anti-inflammatory responses and enhanced antioxidant properties as compared with LF alone. These results indicate the possibility of using LF-HA as an antimicrobial system and biomimetic hydroxyapatite as a candidate for innovative biomedical applications. Keywords: lactoferrin, hydroxyapatite nanocrystals, biomimetism, biological activity, drug delivery

  2. Lactoferrin Adsorbed onto Biomimetic Hydroxyapatite Nanocrystals Controlling - In Vivo - the Helicobacter pylori Infection

    Science.gov (United States)

    Fulgione, Andrea; Nocerino, Nunzia; Iannaccone, Marco; Roperto, Sante; Capuano, Federico; Roveri, Norberto; Lelli, Marco; Crasto, Antonio; Calogero, Armando; Pilloni, Argenia Paola; Capparelli, Rosanna

    2016-01-01

    Background The resistance of Helicobacter pylori to the antibiotic therapy poses the problem to discover new therapeutic approaches. Recently it has been stated that antibacterial, immunomodulatory, and antioxidant properties of lactoferrin are increased when this protein is surface-linked to biomimetic hydroxyapatite nanocrystals. Objective Based on these knowledge, the aim of the study was to investigate the efficacy of lactoferrin delivered by biomimetic hydroxyapatite nanoparticles with cell free supernatant from probiotic Lactobacillus paracasei as an alternative therapy against Helicobacter pylori infection. Methods Antibacterial and antinflammatory properties, humoral antibody induction, histopathological analysis and absence of side effects were evaluated in both in vitro and in vivo studies. Results The tests carried out have been demonstrated better performance of lactoferrin delivered by biomimetic hydroxyapatite nanoparticles combined with cell free supernatant from probiotic Lactobacillus paracasei compared to both lactoferrin and probiotic alone or pooled. Conclusion These findings indicate the effectiveness and safety of our proposed therapy as alternative treatment for Helicobacter pylori infection. PMID:27384186

  3. Evolving application of biomimetic nanostructured hydroxyapatite

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    Norberto Roveri

    2010-11-01

    Full Text Available Norberto Roveri, Michele IafiscoLaboratory of Environmental and Biological Structural Chemistry (LEBSC, Dipartimento di Chimica ‘G. Ciamician’, Alma Mater Studiorum, Università di Bologna, Bologna, ItalyAbstract: By mimicking Nature, we can design and synthesize inorganic smart materials that are reactive to biological tissues. These smart materials can be utilized to design innovative third-generation biomaterials, which are able to not only optimize their interaction with biological tissues and environment, but also mimic biogenic materials in their functionalities. The biomedical applications involve increasing the biomimetic levels from chemical composition, structural organization, morphology, mechanical behavior, nanostructure, and bulk and surface chemical–physical properties until the surface becomes bioreactive and stimulates cellular materials. The chemical–physical characteristics of biogenic hydroxyapatites from bone and tooth have been described, in order to point out the elective sides, which are important to reproduce the design of a new biomimetic synthetic hydroxyapatite. This review outlines the evolving applications of biomimetic synthetic calcium phosphates, details the main characteristics of bone and tooth, where the calcium phosphates are present, and discusses the chemical–physical characteristics of biomimetic calcium phosphates, methods of synthesizing them, and some of their biomedical applications.Keywords: hydroxyapatite, nanocrystals, biomimetism, biomaterials, drug delivery, remineralization

  4. Biomimetic Growth of Hydroxyapatite on Kenaf Fibers

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    Saiful Izwan Abd Razak

    2016-01-01

    Full Text Available Biomimetic hydroxyapatite (HA growth on mercerized kenaf fiber (KF was achieved by immersion in a simulated body fluid (SBF solution with the addition of a chelating agent. An electron micrograph revealed uniform HA layers on the KF within 14 days of immersion with significant vibrational peaks of HA components. The tensile tests showed no significant drops in the unit break of the modified fibers. This new bone-like apatite coating on KF can be useful in the field of bone tissue engineering. The key motivation for this new approach was that it utilizes the abundantly available kenaf plant resource as the biobased template.

  5. Biomimetic synthesis of noble metal nanocrystals

    Science.gov (United States)

    Chiu, Chin-Yi

    At the nanometer scale, the physical and chemical properties of materials heavily depend on their sizes and shapes. This fact has triggered considerable efforts in developing controllable nanomaterial synthesis. The controlled growth of colloidal nanocrystal is a kinetic process, in which high-energy facets grow faster and then vanish, leading to a nanocrystal enclosed by low-energy facets. Identifying a surfactant that can selectively bind to a particular crystal facet and thus lower its surface energy, is critical and challenging in shape controlled synthesis of nanocrystals. Biomolecules exhibiting exquisite molecular recognition properties can be exploited to precisely engineer nanostructured materials. In the first part of my thesis, we employed the phage display technique to select a specific multifunctional peptide sequence which can bind on Pd surface and mediate Pd crystal nucleation and growth, achieving size controlled synthesis of Pd nanocrystals in aqueous solution. We further demonstrated a rational biomimetic approach to the predictable synthesis of nanocrystals enclosed by a particular facet in the case of Pt. Specifically, Pt {100} and Pt {111} facet-specific peptides were identified and used to synthesize Pt nanocubes and Pt nano-tetrahedrons, respectively. The mechanistic studies of Pt {111} facet-specific peptide had led us to study the facet-selective adsorption of aromatic molecules on noble metal surfaces. The discoveries had achieved the development of design strategies to select facet-selective molecules which can synthesize nanocrystals with expected shapes in both Pt and Pd system. At last, we exploited Pt facet-specific peptides and controlled the molecular interaction to produce one- and three- dimensional nanostructures composed of anisotropic nanoparticles in synthetic conditions without supramolecular pre-organization, demonstrating the full potential of biomolecules in mediating material formation process. My research on biomimetic

  6. Adsorption and spectroscopic characterization of lactoferrin on hydroxyapatite nanocrystals.

    Science.gov (United States)

    Iafisco, Michele; Di Foggia, Michele; Bonora, Sergio; Prat, Maria; Roveri, Norberto

    2011-01-28

    Lactoferrin (LF), a well-characterized protein of blood plasma and milk with antioxidant, cariostatic, anticarcinogenic and anti-inflammatory properties, has been adsorbed onto biomimetic hydroxyapatite (HA) nanocrystals at two different pH values (7.4 and 9.0). The interaction was herein investigated by spectroscopic, thermal and microscopic techniques. The positive electrostatic surface potential of LF at pH 7.4 allows a strong surface interaction with the slightly negative HA nanocrystals and avoids the protein-protein interaction, leading to the formation of a coating protein monolayer. In contrast, at pH 9.0 the surface potential of LF is a mix of negative and positive zones favouring the protein-protein interaction and reducing the interaction with HA nanocrystals; as a result a double layer of coating protein was formed. These experimental findings are supported by the good fittings of the adsorption isotherms by different theoretical models according to Langmuir, Freundlich and Langmuir-Freundlich models. The nanosized HA does not appreciably affect the conformation of the adsorbed protein. In fact, using FT-Raman and FT-IR, we found that after adsorption the protein was only slightly unfolded with a small fraction of the α-helix structure being converted into turn, while the β-sheet content remained almost unchanged. The bioactive surface of HA functionalized with LF could be utilized to improve the material performance towards the biological environment for biomedical applications.

  7. Hydroxyapatite coating by biomimetic method on titanium alloy ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. This article reports a biomimetic approach for coating hydroxyapatite on titanium alloy at ambient temperature. In the present study, coating was obtained by soaking the substrate in a 5 times concentrated simulated body fluid (5XSBF) solution for different periods of time with and without the use of CaO–SiO2.

  8. Hydroxyapatite coating by biomimetic method on titanium alloy ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 28; Issue 6. Hydroxyapatite coating by biomimetic method on titanium alloy using concentrated SBF. S Bharati M K Sinha ... Optical microscopic and SEM observations revealed the deposition of Ca–P layer on the titanium alloy by both the methods. Thickness of coating ...

  9. Synthetic Hydroxyapatite as a Biomimetic Oral Care Agent.

    Science.gov (United States)

    Enax, Joachim; Epple, Matthias

    Human tooth enamel consists mostly of minerals, primarily hydroxyapatite, Ca10(PO4)6(OH)2, and thus synthetic hydroxyapatite can be used as a biomimetic oral care agent. This review describes the synthesis and characterization of hydroxyapatite from a chemist's perspective and provides an overview of its current use in oral care, with a focus on dentin hypersensitivity, caries, biofilm management, erosion, and enamel lesions. Reviews and original research papers published in English and German were included. The efficiency of synthetic hydroxyapatite in occluding open dentin tubules, resulting in a protection for sensitive teeth, has been well documented in a number of clinical studies. The first corresponding studies on caries, biofilm management and erosion have provided evidence for a positive effect of hydroxyapatite either as a main or synergistic agent in oral care products. However, more in situ and in vivo studies are needed due to the complexity of the oral milieu and to further clarify existing results. Due to its biocompatibility and similarity to biologically formed hydroxyapatite in natural tooth enamel, synthetic hydroxyapatite is a promising biomimetic oral care ingredient that may extend the scope of preventive dentistry.

  10. Reusable hydroxyapatite nanocrystal sensors for protein adsorption

    International Nuclear Information System (INIS)

    Tagaya, Motohiro; Ikoma, Toshiyuki; Hanagata, Nobutaka; Chakarov, Dinko; Kasemo, Bengt; Tanaka, Junzo

    2010-01-01

    The repeatability of the adsorption and removal of fibrinogen and fetal bovine serum on hydroxyapatite (HAp) nanocrystal sensors was investigated by Fourier transform infrared (FTIR) spectroscopy and quartz crystal microbalance with dissipation (QCM-D) monitoring technique. The HAp nanocrystals were coated on a gold-coated quartz sensor by electrophoretic deposition. Proteins adsorbed on the HAp sensors were removed by (i) ammonia/hydrogen peroxide mixture (APM), (ii) ultraviolet light (UV), (iii) UV/APM, (iv) APM/UV and (v) sodium dodecyl sulfate (SDS) treatments. FTIR spectra of the reused surfaces revealed that the APM and SDS treatments left peptide fragments or the proteins adsorbed on the surfaces, whereas the other methods successfully removed the proteins. The QCM-D measurements indicated that in the removal treatments, fibrinogen was slowly adsorbed in the first cycle because of the change in surface wettability revealed by contact angle measurements. The SDS treatment was not effective in removing proteins. The APM or UV treatment decreased the frequency shifts for the reused HAp sensors. The UV/APM treatment did not induce the frequency shifts but decreased the dissipation shifts. Therefore, we conclude that the APM/UV treatment is the most useful method for reproducing protein adsorption behavior on HAp sensors.

  11. Reusable hydroxyapatite nanocrystal sensors for protein adsorption

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    Motohiro Tagaya, Toshiyuki Ikoma, Nobutaka Hanagata, Dinko Chakarov, Bengt Kasemo and Junzo Tanaka

    2010-01-01

    Full Text Available The repeatability of the adsorption and removal of fibrinogen and fetal bovine serum on hydroxyapatite (HAp nanocrystal sensors was investigated by Fourier transform infrared (FTIR spectroscopy and quartz crystal microbalance with dissipation (QCM-D monitoring technique. The HAp nanocrystals were coated on a gold-coated quartz sensor by electrophoretic deposition. Proteins adsorbed on the HAp sensors were removed by (i ammonia/hydrogen peroxide mixture (APM, (ii ultraviolet light (UV, (iii UV/APM, (iv APM/UV and (v sodium dodecyl sulfate (SDS treatments. FTIR spectra of the reused surfaces revealed that the APM and SDS treatments left peptide fragments or the proteins adsorbed on the surfaces, whereas the other methods successfully removed the proteins. The QCM-D measurements indicated that in the removal treatments, fibrinogen was slowly adsorbed in the first cycle because of the change in surface wettability revealed by contact angle measurements. The SDS treatment was not effective in removing proteins. The APM or UV treatment decreased the frequency shifts for the reused HAp sensors. The UV/APM treatment did not induce the frequency shifts but decreased the dissipation shifts. Therefore, we conclude that the APM/UV treatment is the most useful method for reproducing protein adsorption behavior on HAp sensors.

  12. Formation of Biomimetic Hydroxyapatite Coating on Titanium Plates

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    Ievgen Volodymyrovych PYLYPCHUK

    2014-09-01

    Full Text Available Hydroxyapatite (HA has long been used as a coating material in the implant industry for orthopedic implant applications. HA is the natural inorganic constituent of bone and teeth. By coating titanium (base material of implant engineering because of its lightness and durability with hydroxyapatite, we can provide higher biocompatibility of titanium implants, according to HA ability to form a direct biochemical bond with living tissues. This article reports a biomimetic approach for coating hydroxyapatite with titanium A method of modifying the surface of titanium by organic modifiers (for creating functional groups on the surface, followed by formation "self-assembled" layer of biomimetic hydroxyapatite in simulated body fluid (SBF. FTIR and XPS confirmed the formation of hydroxyapatite coatings on titanium surface. Comparative study of the formation of HA on the surface of titanium plates modified by different functional groups: Ti(≡OH, Ti/(≡Si-OH and Ti/(≡COOH is conducted. It was found that the closest to natural stoichiometric hydroxyapatite Ca/P ratio was obtained on Ti/(≡COOH samples. DOI: http://dx.doi.org/10.5755/j01.ms.20.3.4974

  13. Protein Adsorption and Antibacterial Behavior for Hydroxyapatite Nanocrystals Prepared by Hydrothermal Method

    OpenAIRE

    笠原, 英充; 小形, 信男; 荻原, 隆

    2005-01-01

    Homogeneous hydroxyapatite nanocrystals which have aspect ratio with more than four were synthesized by hydrothermal method. X-ray fluorescence analysis revealed that the Ca/P ratio of hydroxyapatite nanocrystals was maintaining start composition. The protein adsorption properties and bacteria-resistant of hydroxyapatite nanocrystals were investigated. The protein adsorption properties of hydroxyapatite nanocrystals were improvement after the hydrothermal treatment. Bacteria-resistant behavio...

  14. Hydroxyapatite nanocrystals: Simple preparation, characterization and formation mechanism

    International Nuclear Information System (INIS)

    Mohandes, Fatemeh; Salavati-Niasari, Masoud; Fathi, Mohammadhossein; Fereshteh, Zeinab

    2014-01-01

    Crystalline hydroxyapatite (HAP) nanoparticles and nanorods have been successfully synthesized via a simple precipitation method. To control the shape and particle size of HAP nanocrystals, coordination ligands derived from 2-hydroxy-1-naphthaldehyde were first prepared, characterized by Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance ( 1 H-NMR) spectroscopies, and finally applied in the synthesis process of HAP. On the other hand, the HAP nanocrystals were also characterized by several techniques including powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). According to the FE-SEM and TEM micrographs, it was found that the morphology and crystallinity of the HAP powders depended on the coordination mode of the ligands. - Highlights: • HAP nanobundles and nanoparticles have been prepared by a precipitation method. • Morphologies of HAP nanocrystals were controlled by different coordination ligands. • The formation mechanism of hydroxyapatite nanocrystals was also considered

  15. Hydroxyapatite nanocrystals: Simple preparation, characterization and formation mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Mohandes, Fatemeh [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P. O. Box. 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of); Salavati-Niasari, Masoud, E-mail: salavati@kashanu.ac.ir [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P. O. Box. 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of); Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P. O. Box 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of); Fathi, Mohammadhossein [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 8415683111, Islamic Republic of Iran (Iran, Islamic Republic of); Dental Materials Research Center, Isfahan University of Medical Sciences, Isfahan, Islamic Republic of Iran (Iran, Islamic Republic of); Fereshteh, Zeinab [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 8415683111, Islamic Republic of Iran (Iran, Islamic Republic of)

    2014-12-01

    Crystalline hydroxyapatite (HAP) nanoparticles and nanorods have been successfully synthesized via a simple precipitation method. To control the shape and particle size of HAP nanocrystals, coordination ligands derived from 2-hydroxy-1-naphthaldehyde were first prepared, characterized by Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance ({sup 1}H-NMR) spectroscopies, and finally applied in the synthesis process of HAP. On the other hand, the HAP nanocrystals were also characterized by several techniques including powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). According to the FE-SEM and TEM micrographs, it was found that the morphology and crystallinity of the HAP powders depended on the coordination mode of the ligands. - Highlights: • HAP nanobundles and nanoparticles have been prepared by a precipitation method. • Morphologies of HAP nanocrystals were controlled by different coordination ligands. • The formation mechanism of hydroxyapatite nanocrystals was also considered.

  16. Transmission electron microscopy analysis of hydroxyapatite nanocrystals from cattle bones

    International Nuclear Information System (INIS)

    Patel, Sangeeta; Wei, Shanghai; Han, Jie; Gao, Wei

    2015-01-01

    In this present study, hydroxyapatite which was obtained from cattle bones has been heat treated at temperature 400 °C and 600 °C. The microstructure after the treatment has been studied in detail using Transmission electron microscopy (TEM) and X-ray diffraction techniques. The TEM results indicate that natural bone consists of collagen and hydroxyapatite nano-crystals which are needle shaped. The heat treatment influences the crystallinity and growth of these hydroxyapatite nano-crystals known as ‘crystal maturation’ or ‘crystal ageing’. - Highlights: • Hydroxyapatite is obtained from cattle bones. • Material has been characterised using XRD and TEM. • Crystal growth and orientation has been studied in detail.

  17. Transmission electron microscopy analysis of hydroxyapatite nanocrystals from cattle bones

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Sangeeta, E-mail: spt658@aucklanduni.ac.nz [Department of Chemical and Materials Engineering, The University of Auckland, 20 Symonds Street, Auckland 1010 (New Zealand); Wei, Shanghai [Department of Chemical and Materials Engineering, The University of Auckland, 20 Symonds Street, Auckland 1010 (New Zealand); Han, Jie [Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 North Mathews Avenue, Urbana, IL (United States); Gao, Wei [Department of Chemical and Materials Engineering, The University of Auckland, 20 Symonds Street, Auckland 1010 (New Zealand)

    2015-11-15

    In this present study, hydroxyapatite which was obtained from cattle bones has been heat treated at temperature 400 °C and 600 °C. The microstructure after the treatment has been studied in detail using Transmission electron microscopy (TEM) and X-ray diffraction techniques. The TEM results indicate that natural bone consists of collagen and hydroxyapatite nano-crystals which are needle shaped. The heat treatment influences the crystallinity and growth of these hydroxyapatite nano-crystals known as ‘crystal maturation’ or ‘crystal ageing’. - Highlights: • Hydroxyapatite is obtained from cattle bones. • Material has been characterised using XRD and TEM. • Crystal growth and orientation has been studied in detail.

  18. A Novel Nanocomposite Particle of Hydroxyapatite and Silk Fibroin: Biomimetic Synthesis and Its Biocompatibility

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    Lin Niu

    2010-01-01

    Full Text Available A novel bone-like biomaterial of hydroxyapatite (HAP and silk fibroin (SF composite was developed by biomimetic synthesis. The composite was precipitated from drops of Ca(OH2 suspension and H3PO4 solution with SF. With this method, the HAP nanocrystals were obtained by self-assembling on a SF surface whose c-axis was aligned with the long-axis direction of SF in microstructures; this shares the same misconstrues of collagen and HAP with that in the natural bone. The HAP/SF composite then demonstrated that it could promote osteoblast proliferation in vitro and new bone formation in vivo. The novel biomaterial is a promising material for bone replacement and regeneration.

  19. Obtaining hydroxyapatite coatings on titanium by the biomimetic method

    International Nuclear Information System (INIS)

    Paz, A.; Martin, Y.; Pazos, L. M.; Parodi, M. B.; Ybarra, G. O.; Gonzalez, J. E.

    2011-01-01

    In this work, a study about the deposition of hydroxyapatite on a titanium substrate employing the biomimetic method is presented. A solution with high content of calcium and phosphorus (SCS) was used. In addition, activation of titanium with hydrogen peroxide and hydrochloric acid and a subsequent heat treatment was performed. The characterization of materials used and the coating obtained was carried out by Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX). As a result of the activation processes a hydrated titanium oxide was formed. On the active surface, a coating of hydroxyapatite was obtained after a period of 24 h, which has a thickness of about 2-4 μm. (Author) 21 refs.

  20. The precursors effects on biomimetic hydroxyapatite ceramic powders.

    Science.gov (United States)

    Yoruç, Afife Binnaz Hazar; Aydınoğlu, Aysu

    2017-06-01

    In this study, effects of the starting material on chemical, physical, and biological properties of biomimetic hydroxyapatite ceramic powders (BHA) were investigated. Characterization and chemical analysis of BHA powders were performed by using XRD, FT-IR, and ICP-AES. Microstructural features such as size and morphology of the resulting BHA powders were characterized by using BET, nano particle sizer, pycnometer, and SEM. Additionally, biological properties of the BHA ceramic powders were also investigated by using water-soluble tetrazolium salts test (WST-1). According to the chemical analysis of BHA ceramic powders, chemical structures of ceramics which are prepared under different conditions and by using different starting materials show differences. Ceramic powders which are produced at 80°C are mainly composed of hydroxyapatite, dental hydroxyapatite (contain Na and Mg elements in addition to Ca), and calcium phosphate sulfide. However, these structures are altered at high temperatures such as 900°C depending on the features of starting materials and form various calcium phosphate ceramics and/or their mixtures such as Na-Mg-hydroxyapatite, hydroxyapatite, Mg-Whitlockit, and chloroapatite. In vitro cytotoxicity studies showed that amorphous ceramics produced at 80°C and ceramics containing chloroapatite structure as main or secondary phases were found to be extremely cytotoxic. Furthermore, cell culture studies showed that highly crystalline pure hydroxyapatite structures were extremely cytotoxic due to their high crystallinity values. Consequently, the current study indicates that the selection of starting materials which can be used in the production of calcium phosphate ceramics is very important. It is possible to produce calcium phosphate ceramics which have sufficient biocompatibility at physiological pH values and by using appropriate starting materials. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Conjugation of hydroxyapatite nanocrystals with human immunoglobulin G for nanomedical applications.

    Science.gov (United States)

    Iafisco, Michele; Varoni, Elena; Di Foggia, Michele; Pietronave, Stefano; Fini, Milena; Roveri, Norberto; Rimondini, Lia; Prat, Maria

    2012-02-01

    Inorganic nanosized drug carriers are a promising field in nanomedicine applied to cancer. Their conjugation with antibodies combines the properties of the nanoparticles themselves with the specific and selective recognition ability of the antibodies to antigens. Biomimetic carbonate-hydroxyapatite (HA) nanoparticles were synthesized and fully characterized; human IgGs, used as model antibodies, were coupled to these nanocrystals. The maximum loading amount, the interaction modelling, the preferential orientation and the secondary structure modifications were evaluated using theoretical models (Langmuir, Freundlich and Langmuir-Freundlich) spectroscopic (UV-Vis, Raman), calorimetric (TGA), and immunochemical techniques (ELISA, Western Blot). HA nanoparticles of about 30 nm adsorbed human IgGs, in a dose-dependent, saturable and stable manner with micromolar affinity and adsorption capability around 2.3 mg/m(2). Adsorption isotherm could be described by Langmuir-Freundlich model, and was due to both energetically homogeneous and heterogeneous binding sites on HA surface, mainly of electrostatic nature. Binding did not induce secondary structure modification of IgGs. A preferential IgG end-on orientation with the involvement of IgG Fc moiety in the adsorption seems most probable due to the steric hindrance of their Fab domains. Biomimetic HA nanocrystals are suitable substrates to produce nanoparticles which can be functionalized with antibodies for efficient targeted drug delivery to tumours. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Interfacial interactions between calcined hydroxyapatite nanocrystals and substrates.

    Science.gov (United States)

    Okada, Masahiro; Furukawa, Keiko; Serizawa, Takeshi; Yanagisawa, Yoshihiko; Tanaka, Hidekazu; Kawai, Tomoji; Furuzono, Tsutomu

    2009-06-02

    Interfacial interactions between calcined hydroxyapatite (HAp) nanocrystals and surface-modified substrates were investigated by measuring adsorption behavior and adhesion strength with a quartz crystal microbalance (QCM) and a contact-mode atomic force microscope (AFM), respectively. The goal was to develop better control of HAp-nanocrystal coatings on biomedical materials. HAp nanocrystals with rodlike or spherical morphology were prepared by a wet chemical process followed by calcination at 800 degrees C with an antisintering agent to prevent the formation of sintered polycrystals. The substrate surface was modified by chemical reaction with a low-molecular-weight compound, or graft polymerization with a functional monomer. QCM measurement showed that the rodlike HAp nanocrystals adsorbed preferentially onto anionic COOH-modified substrates compared to cationic NH2- or hydrophobic CH3-modified substrates. On the other hand, the spherical nanocrystals adsorbed onto NH2- and COOH-modified substrates, which indicates that the surface properties of the HAp nanocrystals determined their adsorption behavior. The adhesion strength, which was estimated from the force required to move the nanocrystal in contact-mode AFM, on a COOH-grafted substrate prepared by graft polymerization was almost 9 times larger than that on a COOH-modified substrate prepared by chemical reaction with a low-molecular-weight compound, indicating that the long-chain polymer grafted on the substrate mitigated the surface roughness mismatch between the nanocrystal and the substrate. The adhesion strength of the nanocrystal bonded covalently by the coupling reaction to a Si(OCH3)-grafted substrate prepared by graft polymerization was approximately 1.5 times larger than that when adsorbed on the COOH-grafted substrate.

  3. Hydroxyapatite coating on stainless steel by biomimetic method

    International Nuclear Information System (INIS)

    Dias, V.M.; Maia Filho, A.L.M.; Silva, G.; Sousa, E. de; Cardoso, K.R.

    2010-01-01

    Austenitic stainless steels are widely used in implants due to their high mechanical strength and corrosion, however, are not able to connect to bone tissue and were classified as bioinert. The calcium phosphate ceramics such as hydroxyapatite (HA) are bioactive materials and create strong chemical bonds with bone tissue, but its brittleness and low fracture toughness render its use in conditions of high mechanical stress. The coating of steel with the bioactive ceramics such as HA, combines the properties of interest of both materials, accelerating bone formation around the implant. In this study, austenitic stainless steel samples were coated with apatite using the biomimetic method. The effect of three different surface conditions of steel and the immersion time in the SBF solution on the coating was evaluated. The samples were characterized by SEM, EDS and X-ray diffraction. (author)

  4. Hydroxyapatite nanocrystals: simple preparation, characterization and formation mechanism.

    Science.gov (United States)

    Mohandes, Fatemeh; Salavati-Niasari, Masoud; Fathi, Mohammadhossein; Fereshteh, Zeinab

    2014-12-01

    Crystalline hydroxyapatite (HAP) nanoparticles and nanorods have been successfully synthesized via a simple precipitation method. To control the shape and particle size of HAP nanocrystals, coordination ligands derived from 2-hydroxy-1-naphthaldehyde were first prepared, characterized by Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance ((1)H-NMR) spectroscopies, and finally applied in the synthesis process of HAP. On the other hand, the HAP nanocrystals were also characterized by several techniques including powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). According to the FE-SEM and TEM micrographs, it was found that the morphology and crystallinity of the HAP powders depended on the coordination mode of the ligands. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Investigation on the effect of collagen and vitamins on biomimetic hydroxyapatite coating formation on titanium surfaces

    International Nuclear Information System (INIS)

    Ciobanu, Gabriela; Ciobanu, Octavian

    2013-01-01

    This study uses an in vitro experimental approach to investigate the roles of collagen and vitamins in regulating the deposition of hydroxyapatite layer on the pure titanium surface. Titanium implants were coated with a hydroxyapatite layer under biomimetic conditions by using a supersaturated calcification solution (SCS), modified by adding vitamins A and D 3 , and collagen. The hydroxyapatite deposits on titanium were investigated by means of scanning electron microscopy (SEM) coupled with X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy. The results obtained have shown that hydroxyapatite coatings were produced in vitro under vitamins and collagen influence. - Highlights: ► Hydroxyapatite was grown on Ti using a modified supersaturated calcification solution (M-SCS). ► Vitamins (A and D3) and collagen in M-SCS have a significant effect on apatite precipitation. ► M-SCS stimulates a biomimetic apatite deposition with 0.5–1 μm thickness in a short time. ► Hydroxyapatite crystallites have thin plate morphologies and size below 1 μm

  6. Investigation on the effect of collagen and vitamins on biomimetic hydroxyapatite coating formation on titanium surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Ciobanu, Gabriela, E-mail: gciobanu03@yahoo.co.uk [“Gheorghe Asachi” Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, Prof. dr. docent Dimitrie Mangeron Rd., no. 63, zip: 700050, Iasi (Romania); Ciobanu, Octavian [“Grigore T. Popa” University of Medicine and Pharmacy, Faculty of Medical Bioengineering, Universitatii Str., no. 16, zip: 700115, Iasi (Romania)

    2013-04-01

    This study uses an in vitro experimental approach to investigate the roles of collagen and vitamins in regulating the deposition of hydroxyapatite layer on the pure titanium surface. Titanium implants were coated with a hydroxyapatite layer under biomimetic conditions by using a supersaturated calcification solution (SCS), modified by adding vitamins A and D{sub 3}, and collagen. The hydroxyapatite deposits on titanium were investigated by means of scanning electron microscopy (SEM) coupled with X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy. The results obtained have shown that hydroxyapatite coatings were produced in vitro under vitamins and collagen influence. - Highlights: ► Hydroxyapatite was grown on Ti using a modified supersaturated calcification solution (M-SCS). ► Vitamins (A and D3) and collagen in M-SCS have a significant effect on apatite precipitation. ► M-SCS stimulates a biomimetic apatite deposition with 0.5–1 μm thickness in a short time. ► Hydroxyapatite crystallites have thin plate morphologies and size below 1 μm.

  7. Induction of bone formation by smart biphasic hydroxyapatite tricalcium phosphate biomimetic matrices in the non-human primate Papio ursinus

    CSIR Research Space (South Africa)

    Ripamonti, U

    2008-01-01

    Full Text Available Long-term studies in the non-human primate Chacma baboon Papio ursinus were set to investigate the induction of bone formation by biphasic hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) biomimetic matrices. HA/β-TCP biomimetic matrices in a pre...

  8. Investigation on the effect of collagen and vitamins on biomimetic hydroxyapatite coating formation on titanium surfaces.

    Science.gov (United States)

    Ciobanu, Gabriela; Ciobanu, Octavian

    2013-04-01

    This study uses an in vitro experimental approach to investigate the roles of collagen and vitamins in regulating the deposition of hydroxyapatite layer on the pure titanium surface. Titanium implants were coated with a hydroxyapatite layer under biomimetic conditions by using a supersaturated calcification solution (SCS), modified by adding vitamins A and D3, and collagen. The hydroxyapatite deposits on titanium were investigated by means of scanning electron microscopy (SEM) coupled with X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy. The results obtained have shown that hydroxyapatite coatings were produced in vitro under vitamins and collagen influence. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Protein Adsorption and Subsequent Fibroblasts Adhesion on Hydroxyapatite Nanocrystals

    International Nuclear Information System (INIS)

    Tagaya, Motohiro; Ikoma, Toshiyuki; Yoshioka, Tomohiko; Tanaka, Junzo; Takemura, Taro; Hanagata, Nobutaka

    2011-01-01

    Quartz crystal microbalance with dissipation (QCM-D) technique was employed for protein adsorption and subsequent fibroblast adhesion on hydroxyapatite (HAp) nanocrystals. The pre-adsorption of three proteins (albumin (BSA) or fibronectin (Fn) or collagen (Col)) and subsequent adsorption of fetal bovine serum (FBS), and the adhesion of fibroblasts on the surface were in situ monitored, and evaluated with the frequency shift (Δf) and dissipation energy shift (ΔD), and the viscoelastic change as ΔD-Δf plot. The Col adsorption showed larger Δf and ΔD values compared with BSA or Fn adsorption, and the subsequent FBS adsorption depended on the pre-adsorbed proteins. The ΔD-Δf plot of the cell adhesion also showed the different behaviour on the surfaces, indicating the process affected by cell-protein interactions. The confocal laser scanning microscope images of adherent cells showed the different morphology and pseudopod on the surfaces. The cells adhered on the surfaces modified with Fn and Col had the uniaxially expanded shape with fibrous pseudopods, while those modified with BSA had round shape. The different cell-protein interaction would cause the arrangement of extracellular matrix and cytoskeleton changes at the interfaces.

  10. Protein Adsorption and Subsequent Fibroblasts Adhesion on Hydroxyapatite Nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Tagaya, Motohiro; Ikoma, Toshiyuki; Yoshioka, Tomohiko; Tanaka, Junzo [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, Tokyo, Tokyo 152-8550 (Japan); Takemura, Taro; Hanagata, Nobutaka, E-mail: tagaya.m.aa@m.titech.ac.jp [Biomaterials Center, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan)

    2011-10-29

    Quartz crystal microbalance with dissipation (QCM-D) technique was employed for protein adsorption and subsequent fibroblast adhesion on hydroxyapatite (HAp) nanocrystals. The pre-adsorption of three proteins (albumin (BSA) or fibronectin (Fn) or collagen (Col)) and subsequent adsorption of fetal bovine serum (FBS), and the adhesion of fibroblasts on the surface were in situ monitored, and evaluated with the frequency shift ({Delta}f) and dissipation energy shift ({Delta}D), and the viscoelastic change as {Delta}D-{Delta}f plot. The Col adsorption showed larger {Delta}f and {Delta}D values compared with BSA or Fn adsorption, and the subsequent FBS adsorption depended on the pre-adsorbed proteins. The {Delta}D-{Delta}f plot of the cell adhesion also showed the different behaviour on the surfaces, indicating the process affected by cell-protein interactions. The confocal laser scanning microscope images of adherent cells showed the different morphology and pseudopod on the surfaces. The cells adhered on the surfaces modified with Fn and Col had the uniaxially expanded shape with fibrous pseudopods, while those modified with BSA had round shape. The different cell-protein interaction would cause the arrangement of extracellular matrix and cytoskeleton changes at the interfaces.

  11. Study of the toughening mechanisms in bone and biomimetic hydroxyapatite materials using Raman microprobe spectroscopy.

    Science.gov (United States)

    Pezzotti, Giuseppe; Sakakura, Seiji

    2003-05-01

    A Raman microprobe spectroscopy characterization of microscopic fracture mechanisms is presented for a natural hydroxyapatite material (cortical bovine femur) and two synthetic hydroxyapatite-based materials with biomimetic structures-a hydroxyapatite skeleton interpenetrated with a metallic (silver) or a polymeric (nylon-6) phase. In both the natural and synthetic materials, a conspicuous amount of toughening arose from a microscopic crack-bridging mechanism operated by elasto-plastic stretching of unbroken second-phase ligaments along the crack wake. This mechanism led to a rising R-curve behavior. An additional micromechanism, responsible for stress relaxation at the crack tip, was recognized in the natural bone material and was partly mimicked in the hydroxyapatite/silver composite. This crack-tip mechanism conspicuously enhanced the cortical bone material resistance to fracture initiation. A piezo-spectroscopic technique, based on a microprobe measurement of 980 cm(-1) Raman line of hydroxyapatite, enabled us to quantitatively assess in situ the microscopic stress fields developed during fracture both at the crack tip and along the crack wake. Using the Raman piezo-spectroscopy technique, toughening mechanisms were assessed quantitatively and rationally related to the macroscopic fracture characteristics of hydroxyapatite-based materials. Copyright 2003 Wiley Periodicals, Inc.

  12. Biomimetic synthesis of hierarchical crystalline hydroxyapatite fibers in large-scale

    Energy Technology Data Exchange (ETDEWEB)

    Xing, Chaogang; Ge, Suxiang; Huang, Baojun; Bo, Yingying [Institute of Surface Micro and Nano Materials, Xuchang University, Xuchang, Henan Province 461000 (China); Zhang, Di [State Key Lab of Metal Matrix Composites, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030 (China); Zheng, Zhi, E-mail: zhengzhi9999@yahoo.com.cn [Institute of Surface Micro and Nano Materials, Xuchang University, Xuchang, Henan Province 461000 (China)

    2012-06-15

    Highlights: ► Crystalline hierarchical hydroxyapatite (HAp) fibers are synthesized. ► We employ a biomimetic route by using cotton cloth as a natural bio-template. ► We study the effects of pH, ultrasonic cleaning time, and calcination temperature. ► We obtain an optimized reaction condition. ► This is a low cost method for production of hierarchical HAp fibers. -- Abstract: Crystalline hierarchical hydroxyapatite [Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}, HAp)] fibers were successfully synthesized via a biomimetic route by using cotton cloth as a natural bio-template. The effects of pH value, aging time, ultrasonic cleaning time, and calcination temperature on the purity and morphology of the resulting hydroxyapatite (HAp) were monitored by scanning election microscope (SEM), X-ray diffraction (XRD), and infrared spectrophotometer (IR) to obtain an optimized reaction condition, namely, pH 9, ultrasonic cleaning for 1 min, aging for 24 h, and calcination at 600 °C for 4 h. We found that the natural cellulose could not only control the morphology of HAp but also lower its phase transformation temperature. The impact of this method lies in its low cost and successful production of large-scale patterning of three-dimensional hierarchical HAp fibers.

  13. Biomimetic synthesis of hierarchical crystalline hydroxyapatite fibers in large-scale

    International Nuclear Information System (INIS)

    Xing, Chaogang; Ge, Suxiang; Huang, Baojun; Bo, Yingying; Zhang, Di; Zheng, Zhi

    2012-01-01

    Highlights: ► Crystalline hierarchical hydroxyapatite (HAp) fibers are synthesized. ► We employ a biomimetic route by using cotton cloth as a natural bio-template. ► We study the effects of pH, ultrasonic cleaning time, and calcination temperature. ► We obtain an optimized reaction condition. ► This is a low cost method for production of hierarchical HAp fibers. -- Abstract: Crystalline hierarchical hydroxyapatite [Ca 10 (PO 4 ) 6 (OH) 2 , HAp)] fibers were successfully synthesized via a biomimetic route by using cotton cloth as a natural bio-template. The effects of pH value, aging time, ultrasonic cleaning time, and calcination temperature on the purity and morphology of the resulting hydroxyapatite (HAp) were monitored by scanning election microscope (SEM), X-ray diffraction (XRD), and infrared spectrophotometer (IR) to obtain an optimized reaction condition, namely, pH 9, ultrasonic cleaning for 1 min, aging for 24 h, and calcination at 600 °C for 4 h. We found that the natural cellulose could not only control the morphology of HAp but also lower its phase transformation temperature. The impact of this method lies in its low cost and successful production of large-scale patterning of three-dimensional hierarchical HAp fibers.

  14. On the synthesis of tailored biomimetic hydroxyapatite nanoplates through a bioinspired approach in the presence of collagen or chitosan and L-arginine.

    Science.gov (United States)

    Tsetsekou, A; Brasinika, D; Vaou, V; Chatzitheodoridis, E

    2014-10-01

    Controlling the structure of hydroxyapatite nanocrystals is vital for acquiring a consistent product. In an effort to synthesize crystals mimicking the morphology of natural bone's apatite, a bioinspired process was developed based on the use of a natural biomacromolecule, collagen or chitosan, in conjunction with l-arginine to direct the formation of hydroxyapatite from H3PO4 and Ca(OH)2. Different cases were investigated by employing various concentrations of the precursors and two molar ratios of Ca/P 1/1 and 10/6. The reaction was carried out at basic pH conditions and at biomimetic temperature (40°C). The resulting aqueous suspensions were characterized in terms of their rheological behavior, whereas the derived powders were fully evaluated by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction analysis and Raman spectroscopy. The analysis showed that in all cases, the only phase detected was hydroxyapatite of a plate-like morphology very similar to that of natural apatite. The homogeneity of the morphology and the crystal size distribution depend on the precursors' final concentration with the mean size ranging from 5 nm up to 20 nm. The powder that demonstrated the best characteristics in terms of homogeneity was that produced in the presence of collagen for molar ratio of Ca/P 1/1. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Microwave irradiation enhances kinetics of the biomimetic process of hydroxyapatite nanocomposites

    International Nuclear Information System (INIS)

    Guha, Avijit; Nayar, Suprabha; Thatoi, H N

    2010-01-01

    In situ synthesized hydroxyapatite-poly(vinyl) alcohol nanocomposite was subjected to microwave irradiation, post synthesis. Interestingly, the aging time of 1 week required for the normal biomimetic process was reduced to 1 h post microwave irradiation, as characterized by x-ray powder diffraction and transmission electron microscopy. The surface topography shows the tendency of tubules to cross-link with the help of microwave energy. The microwave energy seems to provide a directional pull to the polymer chains which could have led to an enhancement of the kinetics of phase formation. (communication)

  16. Biomimetic properties of an injectable chitosan/nano-hydroxyapatite/collagen composite

    Energy Technology Data Exchange (ETDEWEB)

    Huang Zhi [Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Feng Qingling, E-mail: biomater@mail.tsinghua.edu.cn [Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Yu Bo; Li Songjian [Department of Orthopedics, Zhujiang Hospital of Southern Medical University, Guangzhou 510282 (China)

    2011-04-08

    To meet the challenges of designing an injectable scaffold and regenerating bone with complex three-dimensional (3D) structures, a biomimetic and injectable hydrogel scaffold based on nano-hydroxyapatite (HA), collagen (Col) and chitosan (Chi) is synthesized. The chitosan/nano-hydroxyapatite/collagen (Chi/HA/Col) solution rapidly forms a stable gel at body temperature. It shows some features of natural bone both in main composition and microstructure. The Chi/HA/Col system can be expected as a candidate for workable systemic minimally invasive scaffolds with surface properties similar to physiological bone based on scanning electron microscopic (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) results.

  17. Biomimetic properties of an injectable chitosan/nano-hydroxyapatite/collagen composite

    International Nuclear Information System (INIS)

    Huang Zhi; Feng Qingling; Yu Bo; Li Songjian

    2011-01-01

    To meet the challenges of designing an injectable scaffold and regenerating bone with complex three-dimensional (3D) structures, a biomimetic and injectable hydrogel scaffold based on nano-hydroxyapatite (HA), collagen (Col) and chitosan (Chi) is synthesized. The chitosan/nano-hydroxyapatite/collagen (Chi/HA/Col) solution rapidly forms a stable gel at body temperature. It shows some features of natural bone both in main composition and microstructure. The Chi/HA/Col system can be expected as a candidate for workable systemic minimally invasive scaffolds with surface properties similar to physiological bone based on scanning electron microscopic (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) results.

  18. Mechanical response and multilevel structure of biomimetic hydroxyapatite/polygalacturonic/chitosan nanocomposites

    International Nuclear Information System (INIS)

    Verma, Devendra; Katti, Kalpana S.; Katti, Dinesh R.; Mohanty, Bedabibhas

    2008-01-01

    Using an in situ mineralization process that is biomimetic we have synthesized new nanocomposites of chitosan/hydroxyapatite in 50-50 ratio(ChiHAP50), polygalacturonic acid/hydroxyapatite in 50-50 ratio (PgAHAP50) and Chitosan/hydroxyapatite/Polygalacturonic acid (ChiPgAHAP50). Polygalacturonic acid (PgA) is electrostatically complementary to chitosan, and thus is expected to provide stronger interfacial interactions and improve mechanical response. Atomic force imaging of fractured and polished surfaces suggests a multilevel organization in the hydroxyapatite/biopolymer nanocomposite. The AFM images of ChiPgAHAP50 nanocomposite display presence of chitosan rich and polygalacturonic rich domains. These chitosan rich and PgA rich domains are made of smaller globular shaped particles in which, hydroxyapatite nano-particles are embedded in the biopolymer matrix. The average size of the hydroxyapatite particles in PgAHAP50, ChiHAP50 and ChiPgAHAP50 were found to be 25, 42 and 34 nm respectively. The elastic moduli determined from nanoindentation of PgAHAP50, ChiHAP50 and ChiPgAHAP50 composites are 29.81, 17.56 and 23.62 GPa respectively. Hardness values of the three composites in the same order were found to be 1.56, 0.65 and 1.14 GPa respectively. Macro-mechanical tests showed significant enhancement in elastic moduli, strain to failure and compressive strength of ChiPgAHAP50 composites over ChiHAP50 and PgAHAP50

  19. On the synthesis of tailored biomimetic hydroxyapatite nanoplates through a bioinspired approach in the presence of collagen or chitosan and L-arginine

    Energy Technology Data Exchange (ETDEWEB)

    Tsetsekou, A., E-mail: athtse@metal.ntua.gr; Brasinika, D.; Vaou, V.; Chatzitheodoridis, E.

    2014-10-01

    Controlling the structure of hydroxyapatite nanocrystals is vital for acquiring a consistent product. In an effort to synthesize crystals mimicking the morphology of natural bone's apatite, a bioinspired process was developed based on the use of a natural biomacromolecule, collagen or chitosan, in conjunction with L-arginine to direct the formation of hydroxyapatite from H{sub 3}PO{sub 4} and Ca(OH){sub 2}. Different cases were investigated by employing various concentrations of the precursors and two molar ratios of Ca/P 1/1 and 10/6. The reaction was carried out at basic pH conditions and at biomimetic temperature (40 °C). The resulting aqueous suspensions were characterized in terms of their rheological behavior, whereas the derived powders were fully evaluated by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction analysis and Raman spectroscopy. The analysis showed that in all cases, the only phase detected was hydroxyapatite of a plate-like morphology very similar to that of natural apatite. The homogeneity of the morphology and the crystal size distribution depend on the precursors' final concentration with the mean size ranging from 5 nm up to 20 nm. The powder that demonstrated the best characteristics in terms of homogeneity was that produced in the presence of collagen for molar ratio of Ca/P 1/1. - Highlights: • Hydroxyapatite nanoplates similar to those of bone's apatite were developed. • A novel approach simulating the biomineralization environment was developed. • L-Arginine was combined with collagen or chitosan to direct HAp nucleation. • Depending on reaction conditions a very homogeneous nanostructure is attained.

  20. On the synthesis of tailored biomimetic hydroxyapatite nanoplates through a bioinspired approach in the presence of collagen or chitosan and L-arginine

    International Nuclear Information System (INIS)

    Tsetsekou, A.; Brasinika, D.; Vaou, V.; Chatzitheodoridis, E.

    2014-01-01

    Controlling the structure of hydroxyapatite nanocrystals is vital for acquiring a consistent product. In an effort to synthesize crystals mimicking the morphology of natural bone's apatite, a bioinspired process was developed based on the use of a natural biomacromolecule, collagen or chitosan, in conjunction with L-arginine to direct the formation of hydroxyapatite from H 3 PO 4 and Ca(OH) 2 . Different cases were investigated by employing various concentrations of the precursors and two molar ratios of Ca/P 1/1 and 10/6. The reaction was carried out at basic pH conditions and at biomimetic temperature (40 °C). The resulting aqueous suspensions were characterized in terms of their rheological behavior, whereas the derived powders were fully evaluated by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction analysis and Raman spectroscopy. The analysis showed that in all cases, the only phase detected was hydroxyapatite of a plate-like morphology very similar to that of natural apatite. The homogeneity of the morphology and the crystal size distribution depend on the precursors' final concentration with the mean size ranging from 5 nm up to 20 nm. The powder that demonstrated the best characteristics in terms of homogeneity was that produced in the presence of collagen for molar ratio of Ca/P 1/1. - Highlights: • Hydroxyapatite nanoplates similar to those of bone's apatite were developed. • A novel approach simulating the biomineralization environment was developed. • L-Arginine was combined with collagen or chitosan to direct HAp nucleation. • Depending on reaction conditions a very homogeneous nanostructure is attained

  1. Biomimetic fabrication of a three-level hierarchical calcium phosphate/collagen/hydroxyapatite scaffold for bone tissue engineering

    International Nuclear Information System (INIS)

    Zhou, Changchun; Ye, Xingjiang; Fan, Yujiang; Tan, Yanfei; Qing, Fangzu; Zhang, Xingdong; Ma, Liang

    2014-01-01

    A three-level hierarchical calcium phosphate/collagen/hydroxyapatite (CaP/Col/HAp) scaffold for bone tissue engineering was developed using biomimetic synthesis. Porous CaP ceramics were first prepared as substrate materials to mimic the porous bone structure. A second-level Col network was then composited into porous CaP ceramics by vacuum infusion. Finally, a third-level HAp layer was achieved by biomimetic mineralization. The three-level hierarchical biomimetic scaffold was characterized using scanning electron microscopy, energy-dispersive x-ray spectra, x-ray diffraction and Fourier transform infrared spectroscopy, and the mechanical properties of the scaffold were evaluated using dynamic mechanical analysis. The results show that this scaffold exhibits a similar structure and composition to natural bone tissues. Furthermore, this three-level hierarchical biomimetic scaffold showed enhanced mechanical strength compared with pure porous CaP scaffolds. The biocompatibility and osteoinductivity of the biomimetic scaffolds were evaluated using in vitro and in vivo tests. Cell culture results indicated the good biocompatibility of this biomimetic scaffold. Faster and increased bone formation was observed in these scaffolds following a six-month implantation in the dorsal muscles of rabbits, indicating that this biomimetic scaffold exhibits better osteoinductivity than common CaP scaffolds. (papers)

  2. Electrospun polyvinyl alcohol–collagen–hydroxyapatite nanofibers: a biomimetic extracellular matrix for osteoblastic cells

    International Nuclear Information System (INIS)

    Song Wei; Shi Tong; Ren Weiping; Markel, David C; Wang Sunxi; Mao Guangzhao

    2012-01-01

    The failure of prosthesis after total joint replacement is due to the lack of early implant osseointegration. In this study polyvinyl alcohol–collagen–hydroxyapatite (PVA-Col-HA) electrospun nanofibrous meshes were fabricated as a biomimetic bone-like extracellular matrix for the modification of orthopedic prosthetic surfaces. In order to reinforce the PVA nanofibers, HA nanorods and Type I collagen were incorporated into the nanofibers. We investigated the morphology, biodegradability, mechanical properties and biocompatibility of the prepared nanofibers. Our results showed these inorganic–organic blended nanofibers to be degradable in vitro. The encapsulated nano-HA and collagen interacted with the PVA content, reinforcing the hydrolytic resistance and mechanical properties of nanofibers that provided longer lasting stability. The encapsulated nano-HA and collagen also enhanced the adhesion and proliferation of murine bone cells (MC3T3) in vitro. We propose the PVA-Col-HA nanofibers might be promising modifying materials on implant surfaces for orthopedic applications. (paper)

  3. Calcium carbonate hybrid coating promotes the formation of biomimetic hydroxyapatite on titanium surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Marcos Antônio E.; Ruiz, Gilia C.M. [Departamento de Química-Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, SP (Brazil); Faria, Amanda N. [Departamento de Química-Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, SP (Brazil); Departamento de Bioquímica e Imunologia-Faculdade de Medicina de Ribeirão Preto Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Zancanela, Daniela C.; Pereira, Lourivaldo S.; Ciancaglini, Pietro [Departamento de Química-Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, SP (Brazil); Ramos, Ana P., E-mail: anapr@ffclrp.usp.br [Departamento de Química-Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, SP (Brazil)

    2016-05-01

    Graphical abstract: - Highlights: • CaCO{sub 3} continuous films were deposited on titanium discs using a biomimetic approach. • The coatings origin hydroxyapatite when immersed in simulated body fluid. • The wettability and the free energy of the surfaces were increased after the treatment. • The coated titanium discs are bioactive and non-toxic to osteoblasts. - Abstract: CaCO{sub 3} particles dispersed in liquid media have proven to be good inductors of hydroxyapatite (HAp) growth. However, the use of CaCO{sub 3} deposited as thin films for this propose is unknown. Here, we report the growth of CaCO{sub 3} continuous films on Langmuir–Blodgett (LB) modified titanium surfaces and its use as HAp growth inductor. The Ti surfaces were modified with two, four, and six layers of dihexadecylphosphate (DHP)-LB films containing Ca{sup 2+}, exposed to CO{sub 2} (g) for 12 h. The modified surfaces were immersed in simulated body fluid (SBF) at 37 °C for 36 h and submitted to bioactivity studies. This procedure originates bioactive coatings composed by non-stoichiometric HAp as evidenced by Fourier-Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS). The presence of the CaCO{sub 3} film as pre-coating diminished the time necessary to growth continuous and homogeneous HAp films using a biomimetic approach. The surface properties of the films regarding their roughness, composition, charge, wettability, and surface free energy (γ{sub s}) were accessed. The presence of HAp increased the wettability and γ{sub s} of the surfaces. The coatings are not toxic for osteoblasts as observed for cell viability assays obtained after 7 and 14 days of culture. Moreover, the CaCO{sub 3} thin films promote the recovery of the osteoblasts viability more than the Ti surfaces themselves.

  4. Calcium carbonate hybrid coating promotes the formation of biomimetic hydroxyapatite on titanium surfaces

    International Nuclear Information System (INIS)

    Cruz, Marcos Antônio E.; Ruiz, Gilia C.M.; Faria, Amanda N.; Zancanela, Daniela C.; Pereira, Lourivaldo S.; Ciancaglini, Pietro; Ramos, Ana P.

    2016-01-01

    Graphical abstract: - Highlights: • CaCO 3 continuous films were deposited on titanium discs using a biomimetic approach. • The coatings origin hydroxyapatite when immersed in simulated body fluid. • The wettability and the free energy of the surfaces were increased after the treatment. • The coated titanium discs are bioactive and non-toxic to osteoblasts. - Abstract: CaCO 3 particles dispersed in liquid media have proven to be good inductors of hydroxyapatite (HAp) growth. However, the use of CaCO 3 deposited as thin films for this propose is unknown. Here, we report the growth of CaCO 3 continuous films on Langmuir–Blodgett (LB) modified titanium surfaces and its use as HAp growth inductor. The Ti surfaces were modified with two, four, and six layers of dihexadecylphosphate (DHP)-LB films containing Ca 2+ , exposed to CO 2 (g) for 12 h. The modified surfaces were immersed in simulated body fluid (SBF) at 37 °C for 36 h and submitted to bioactivity studies. This procedure originates bioactive coatings composed by non-stoichiometric HAp as evidenced by Fourier-Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS). The presence of the CaCO 3 film as pre-coating diminished the time necessary to growth continuous and homogeneous HAp films using a biomimetic approach. The surface properties of the films regarding their roughness, composition, charge, wettability, and surface free energy (γ s ) were accessed. The presence of HAp increased the wettability and γ s of the surfaces. The coatings are not toxic for osteoblasts as observed for cell viability assays obtained after 7 and 14 days of culture. Moreover, the CaCO 3 thin films promote the recovery of the osteoblasts viability more than the Ti surfaces themselves.

  5. Influence of the modulated two-step synthesis of biogenic hydroxyapatite on biomimetic products' surface

    Science.gov (United States)

    Miculescu, Florin; Mocanu, Aura Cătălina; Stan, George E.; Miculescu, Marian; Maidaniuc, Andreea; Cîmpean, Anisoara; Mitran, Valentina; Voicu, Stefan Ioan; Machedon-Pisu, Teodor; Ciocan, Lucian Toma

    2018-04-01

    Processing calcium-rich natural resources, such as marble and mussel seashells, into biomimetic products could constitute an environmentally-friendly and economically sustainable alternative given their geographical widespread. Hitherto, their value for biomedicine was demonstrated only for seashells, with the technological exploitation approaches still facing challenges with respect to the identification of generic synthesis parameters capable to allow the reproducible and designed synthesis of calcium phosphate at an industrial-ready level. In this study was targeted the optimization of Rathje synthesis method for the fabrication of biogenic calcium phosphates, by conveniently adjusting the chemical composition of employed reagents. It was shown that post-synthesis heat-treatment of compacted powders is the key step for inducing structural transformations suitable to attain biomimetic products for reconstructive orthopedic applications. The sintered materials have been multi-parametricallyevaluated from morpho-compositional, structural, wettability, mechanical and cytocompatibility points of view and the results have been cross-examined and discussed. Convenient and efficient preparation routes to produce biogenic hydroxyapatite have been identified. The functional performances of the as-prepared biogenic ceramics endorse their use as a solid and inexpensive alternative source material for the fabrication of various bone regenerative products and implant coatings.

  6. Electrospun biomimetic scaffold of hydroxyapatite/chitosan supports enhanced osteogenic differentiation of mMSCs

    International Nuclear Information System (INIS)

    Peng Hongju; Feng Bei; Yuan Huihua; Zhang Yanzhong; Yin Zi; Liu Huanhuan; Chen Xiao; Ouyang Hongwei; Su Bo

    2012-01-01

    Engaging functional biomaterial scaffolds to regulate stem cell differentiation has drawn a great deal of attention in the tissue engineering and regenerative medicine community. In this study, biomimetic composite nanofibrous scaffolds of hydroxyapatite/chitosan (HAp/CTS) were prepared to investigate their capacity for inducing murine mesenchymal stem cells (mMSCs) to differentiate into the osteogenic lineage, in the absence and presence of an osteogenic supplementation (i.e., ascorbic acid, β-glycerol phosphate, and dexamethasone), respectively. Using electrospun chitosan (CTS) nanofibrous scaffolds as the control, cell morphology, growth, specific osteogenic genes expression, and quantified proteins secretion on the HAp/CTS scaffolds were sequentially examined and assessed. It appeared that the HAp/CTS scaffolds supported better attachment and proliferation of the mMSCs. Most noteworthy was that in the absence of the osteogenic supplementation, expression of osteogenic genes including collagen I (Col I), runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP), and osteocalcin (OCN) were significantly upregulated in mMSCs cultured on the HAp/CTS nanofibrous scaffolds. Also increased secretion of the osteogenesis protein markers of alkaline phosphatase and collagen confirmed that the HAp/CTS nanofibrous scaffold markedly promoted the osteogenic commitment in the mMSCs. Moreover, the presence of osteogenic supplementation proved an enhanced efficacy of mMSC osteogenesis on the HAp/CTS nanofibrous scaffolds. Collectively, this study demonstrated that the biomimetic nanofibrous HAp/CTS scaffolds could support and enhance the adhesion, proliferation, and particularly osteogenic differentiation of the mMSCs. It also substantiated the potential of using biomimetic nanofibrous scaffolds of HAp/CTS for functional bone repair and regeneration applications. (paper)

  7. Biomimetic design of a bacterial cellulose/hydroxyapatite nanocomposite for bone healing applications

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, Kristen A., E-mail: kazimmer@vt.edu [Department of Materials Science and Engineering, Virginia Tech, Blacksburg, VA 24060 (United States); School of Biomedical Engineering Sciences, Virginia Tech, Blacksburg, VA 24060 (United States); LeBlanc, Jill M.; Sheets, Kevin T.; Fox, Robert W. [Department of Materials Science and Engineering, Virginia Tech, Blacksburg, VA 24060 (United States); Gatenholm, Paul [Department of Materials Science and Engineering, Virginia Tech, Blacksburg, VA 24060 (United States); School of Biomedical Engineering Sciences, Virginia Tech, Blacksburg, VA 24060 (United States)

    2011-01-01

    This study describes the design and synthesis of bacterial cellulose/hydroxyapatite nanocomposites for bone healing applications using a biomimetic approach. Bacterial cellulose (BC) with various surface morphologies (pellicles and tubes) was negatively charged by the adsorption of carboxymethyl cellulose (CMC) to initiate nucleation of calcium-deficient hydroxyapatite (cdHAp). The cdHAp was grown in vitro via dynamic simulated body fluid (SBF) treatments over a one week period. Characterization of the mineralized samples was done with X-ray Photoelectron Spectroscopy (XPS) and Field Emission Scanning Electron Microscopy (FESEM) with Energy Dispersive Spectroscopy (EDS). The amount of cdHAp observed varied among different samples. XPS demonstrated that the atomic presence of calcium and phosphorus ranged from 0.44 at.% to 7.71 at.% Ca and 0.27 at.% to 11.18 at.% P. The Ca/P overall ratio ranged from 1.22 to 1.92. FESEM images showed that the cdHAp crystal size increased with increasing nanocellulose fibril density. To determine the viability of the scaffolds in vitro, the morphology and differentiation of osteoprogenitor cells was analyzed using fluorescence microscopy and alkaline phosphatase gene expression. The presence of cdHAp crystals on BC surfaces resulted in increased cell attachment.

  8. XPS and XANES studies of biomimetic composites based on B-type nano-hydroxyapatite

    Science.gov (United States)

    Goloshchapov, D. L.; Gushchin, M. S.; Kashkarov, V. M.; Seredin, P. V.; Ippolitov, Y. A.; Khmelevsky, N. O.; Aksenenko, A. Yu.

    2018-06-01

    The paper presents an investigation of the local atomic structure of nanocrystalline carbonate-substituted hydroxyapatite (CHAP) contained in biomimetic composites - analogues of intact human tooth tissues. Using the XPS technique, the presence of impurity Mg and F atoms and structurally bound carbon in CHAP, at the concentrations typical of apatite enamel and dentine was determined. The XANES method was used to study the changes occurring in P L2,3 spectra of biocomposites with CHAP, depending on the percentage of the amino acid matrix. The appearance of maxima in the spectra of XANES P L2,3 near 135.7 eV for the samples with the composition of amino acid complex/hydroxyapatite - 5/95, 25/75 and the splitting of a broad peak of 146.9 eV in the spectrum of a biocomposite with a composition of 40/60 indicates at the interaction of molecular complex of amino acids with atomic environment of phosphorus. This fact can be used in the fundamental medicine for synthesizing of new biomaterials in dentistry.

  9. Silica enhanced formation of hydroxyapatite nanocrystals in simulated body fluid (SBF) at 37 deg. C

    Energy Technology Data Exchange (ETDEWEB)

    Sadjadi, M.S., E-mail: m.s.sadjad@gmail.com [Department of Chemistry, Sciences and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Ebrahimi, H.R. [Department of Chemistry, Sciences and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Meskinfam, M. [Department of Chemistry, Tonekabon Branch, Islamic Azad University, Tonekabon (Iran, Islamic Republic of); Zare, K. [Department of Chemistry, University of Shahid Beheshti, Eveen Tehran (Iran, Islamic Republic of)

    2011-10-17

    Highlights: {yields} We report on fast formation of hexagonal nanocrystals of calcium hydroxyapatite (HA) in silica-containing simulated body fluid solution at 37 deg. C. {yields} Bioactivity and biodegradability of TCP precursor have been confirmed by the dissolution of TCP and formation of a bone like layer of new HA nanoparticles outside of the precursor after 24 h soaking in SBF solution. {yields} Successive nucleation and formation of tiny hexagonal HA nanoplates and nanorods have been confirmed by TEM results after 24 h soaking of TCP in silica-containing BSF solution. - Abstract: The chemical modification of implant (prosthesis) surfaces is being investigated worldwide for improving the fixation of orthopaedic and dental implants. The main goal in this surface modification approach is to achieve a faster bone growth and chemical bonding of the implant to the newly generated and/or remodeled bone. In this work, we report fast formation of hexagonal nanocrystals of calcium hydroxyapatite (HA) in simulated body fluid (SBF, inorganic components of human blood plasma) solutions at 37 deg. C, using calcium phosphate (TCP) and sodium silicate as precursors. Characterization and chemical analysis of the synthesized powders were performed by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results indicated enhanced nucleation and formation of bone like layer of HA nanocrystals at the surface of TCP nanoparticles and occurrence of HA nanocrystals during 24 h soaking of TCP in SBF solution containing silica ions. The average size of a nanoparticle, using Scherrer formula, was found to be 18.2 nm.

  10. Silica enhanced formation of hydroxyapatite nanocrystals in simulated body fluid (SBF) at 37 deg. C

    International Nuclear Information System (INIS)

    Sadjadi, M.S.; Ebrahimi, H.R.; Meskinfam, M.; Zare, K.

    2011-01-01

    Highlights: → We report on fast formation of hexagonal nanocrystals of calcium hydroxyapatite (HA) in silica-containing simulated body fluid solution at 37 deg. C. → Bioactivity and biodegradability of TCP precursor have been confirmed by the dissolution of TCP and formation of a bone like layer of new HA nanoparticles outside of the precursor after 24 h soaking in SBF solution. → Successive nucleation and formation of tiny hexagonal HA nanoplates and nanorods have been confirmed by TEM results after 24 h soaking of TCP in silica-containing BSF solution. - Abstract: The chemical modification of implant (prosthesis) surfaces is being investigated worldwide for improving the fixation of orthopaedic and dental implants. The main goal in this surface modification approach is to achieve a faster bone growth and chemical bonding of the implant to the newly generated and/or remodeled bone. In this work, we report fast formation of hexagonal nanocrystals of calcium hydroxyapatite (HA) in simulated body fluid (SBF, inorganic components of human blood plasma) solutions at 37 deg. C, using calcium phosphate (TCP) and sodium silicate as precursors. Characterization and chemical analysis of the synthesized powders were performed by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results indicated enhanced nucleation and formation of bone like layer of HA nanocrystals at the surface of TCP nanoparticles and occurrence of HA nanocrystals during 24 h soaking of TCP in SBF solution containing silica ions. The average size of a nanoparticle, using Scherrer formula, was found to be 18.2 nm.

  11. Low temperature synthesis and characterization of carbonated hydroxyapatite nanocrystals

    Science.gov (United States)

    Anwar, Aneela; Asghar, Muhammad Nadeem; Kanwal, Qudsia; Kazmi, Mohsin; Sadiqa, Ayesha

    2016-08-01

    Carbonate substituted hydroxyapatite (CHA) nanorods were synthesized via coprecipitation method from aqueous solution of calcium nitrate tetrahydrate and diammonium hydrogen phosphate (with urea as carbonate ion source) in the presence of ammonium hydroxide solution at 70 °C at the conditions of pH 11. The obtained powders were physically characterized using transmission electron microscopy (TEM), X-ray powder diffraction analysis (XRD), and FTIR and Raman spectroscopy. The particle size was evaluated by Dynamic light scattering (DLS). The chemical structural analysis of as prepared sample was performed using X-ray photoelectron spectroscopy (XPS). After ageing for 12 h, and heat treatment at 1000 °C for 1 h, the product was obtained as highly crystalline nanorods of CHA.

  12. Biomimetic three-dimensional nanocrystalline hydroxyapatite and magnetically synthesized single-walled carbon nanotube chitosan nanocomposite for bone regeneration

    Directory of Open Access Journals (Sweden)

    Im O

    2012-04-01

    Full Text Available Owen Im1, Jian Li2, Mian Wang2, Lijie Grace Zhang2,3, Michael Keidar2,31Department of Biomedical Engineering, Duke University, Durham, NC; 2Department of Mechanical and Aerospace Engineering, 3Institute for Biomedical Engineering and Institute for Nanotechnology, The George Washington University, Washington, DC, USABackground: Many shortcomings exist in the traditional methods of treating bone defects, such as donor tissue shortages for autografts and disease transmission for allografts. The objective of this study was to design a novel three-dimensional nanostructured bone substitute based on magnetically synthesized single-walled carbon nanotubes (SWCNT, biomimetic hydrothermally treated nanocrystalline hydroxyapatite, and a biocompatible hydrogel (chitosan. Both nanocrystalline hydroxyapatite and SWCNT have a biomimetic nanostructure, excellent osteoconductivity, and high potential to improve the load-bearing capacity of hydrogels.Methods: Specifically, three-dimensional porous chitosan scaffolds with different concentrations of nanocrystalline hydroxyapatite and SWCNT were created to support the growth of human osteoblasts (bone-forming cells using a lyophilization procedure. Two types of SWCNT were synthesized in an arc discharge with a magnetic field (B-SWCNT and without a magnetic field (N-SWCNT for improving bone regeneration.Results: Nanocomposites containing magnetically synthesized B-SWCNT had superior cytocompatibility properties when compared with nonmagnetically synthesized N-SWCNT. B-SWCNT have much smaller diameters and are twice as long as their nonmagnetically prepared counterparts, indicating that the dimensions of carbon nanotubes can have a substantial effect on osteoblast attachment.Conclusion: This study demonstrated that a chitosan nanocomposite with both B-SWCNT and 20% nanocrystalline hydroxyapatite could achieve a higher osteoblast density when compared with the other experimental groups, thus making this nanocomposite

  13. Biomimetic three-dimensional nanocrystalline hydroxyapatite and magnetically synthesized single-walled carbon nanotube chitosan nanocomposite for bone regeneration

    Science.gov (United States)

    Im, Owen; Li, Jian; Wang, Mian; Zhang, Lijie Grace; Keidar, Michael

    2012-01-01

    Background Many shortcomings exist in the traditional methods of treating bone defects, such as donor tissue shortages for autografts and disease transmission for allografts. The objective of this study was to design a novel three-dimensional nanostructured bone substitute based on magnetically synthesized single-walled carbon nanotubes (SWCNT), biomimetic hydrothermally treated nanocrystalline hydroxyapatite, and a biocompatible hydrogel (chitosan). Both nanocrystalline hydroxyapatite and SWCNT have a biomimetic nanostructure, excellent osteoconductivity, and high potential to improve the load-bearing capacity of hydrogels. Methods Specifically, three-dimensional porous chitosan scaffolds with different concentrations of nanocrystalline hydroxyapatite and SWCNT were created to support the growth of human osteoblasts (bone-forming cells) using a lyophilization procedure. Two types of SWCNT were synthesized in an arc discharge with a magnetic field (B-SWCNT) and without a magnetic field (N-SWCNT) for improving bone regeneration. Results Nanocomposites containing magnetically synthesized B-SWCNT had superior cytocompatibility properties when compared with nonmagnetically synthesized N-SWCNT. B-SWCNT have much smaller diameters and are twice as long as their nonmagnetically prepared counterparts, indicating that the dimensions of carbon nanotubes can have a substantial effect on osteoblast attachment. Conclusion This study demonstrated that a chitosan nanocomposite with both B-SWCNT and 20% nanocrystalline hydroxyapatite could achieve a higher osteoblast density when compared with the other experimental groups, thus making this nanocomposite promising for further exploration for bone regeneration. PMID:22619545

  14. Hydroxyapatite nanocrystals functionalized with alendronate as bioactive components for bone implant coatings to decrease osteoclastic activity

    Science.gov (United States)

    Bosco, Ruggero; Iafisco, Michele; Tampieri, Anna; Jansen, John A.; Leeuwenburgh, Sander C. G.; van den Beucken, Jeroen J. J. P.

    2015-02-01

    The integration of bone implants within native bone tissue depends on periprosthetic bone quality, which is severely decreased in osteoporotic patients. In this work, we have synthesized bone-like hydroxyapatite nanocrystals (nHA) using an acid-base neutralization reaction and analysed their physicochemical properties. Subsequently, we have functionalized the nHA with alendronate (nHAALE), a well-known bisphosphonate drug used for the treatment of osteoporosis. An in vitro osteoclastogenesis test was carried out to evaluate the effect of nHAALE on the formation of osteoclast-like cells from monocytic precursor cells (i.e. RAW264.7 cell line) showing that nHAALE significantly promoted apoptosis of osteoclast-like cells. Subsequently, nHA and nHAALE were deposited on titanium disks using electrospray deposition (ESD), for which characterisation of the deposited coatings confirmed the presence of alendronate in nHAALE coatings with nanoscale thickness of about 700 nm. These results indicate that alendronate linked to hydroxyapatite nanocrystals has therapeutic potential and nHAALE can be considered as an appealing coating constituent material for orthopaedic and oral implants for application in osteoporotic patients.

  15. Fabrication and characterization of novel biomimetic PLLA/cellulose/hydroxyapatite nanocomposite for bone repair applications

    Energy Technology Data Exchange (ETDEWEB)

    Eftekhari, Samin [Department of Chemical Engineering, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3 (Canada); El Sawi, Ihab; Bagheri, Zahra Shaghayegh [Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3 (Canada); Turcotte, Ginette [Department of Chemical Engineering, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3 (Canada); Bougherara, Habiba, E-mail: habiba.bougherara@ryerson.ca [Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3 (Canada)

    2014-06-01

    The purpose of this research is to develop and characterize a novel biomimetic nanocomposite that closely mimics the properties of real bone such as morphology, composition and mechanical characteristics. This novel porous nanocomposite is composed of cotton-sourced cellulose microcrystals, hydroxyapatite nanoparticles and poly L-lactide acid. A unique combination of commonly used fabrication procedures has been developed including pre-treatment of particles using a coupling agent. The effect of various weight ratios of the reinforcing agents was evaluated to assess their influence on the chemical, thermal, and mechanical properties of the nanocomposites. The prepared nanocomposites were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry and compression testing. Our results indicated the presence of molecular interactions between all components leading to an increase of the crystallinity of the polymer from 50% to 80%. Compression test results revealed that increasing the weight ratio of microcrystalline cellulose/poly L-lactide acid and hydroxyapatite/poly L-lactide acid from 0.1 to 0.5 enhanced the compressive yield stress from 0.127 to 2.2 MPa and The Young's modulus from 6.6 to 38 MPa, respectively. It was found that the fabricated nanocomposites are comparable with the trabecular bone from compositional, structural, and mechanical point of view. - Highlights: • Fabrication of PLLA/HA/cellulose composites that mimic the spongeous bone • Homogenous dispersion of the reinforcing agents in the PLLA matrix was attained. • More efficient interface between the PLLA and the reinforcing agents was achieved. • Preliminary in vitro biocompatibility test showed the nontoxicity of the composite. • The crystallinity, the compressive strength and modulus were investigated.

  16. Ribose mediated crosslinking of collagen-hydroxyapatite hybrid scaffolds for bone tissue regeneration using biomimetic strategies.

    Science.gov (United States)

    Krishnakumar, Gopal Shankar; Gostynska, Natalia; Campodoni, Elisabetta; Dapporto, Massimiliano; Montesi, Monica; Panseri, Silvia; Tampieri, Anna; Kon, Elizaveta; Marcacci, Maurilio; Sprio, Simone; Sandri, Monica

    2017-08-01

    This study explores for the first time the application of ribose as a highly biocompatible agent for the crosslinking of hybrid mineralized constructs, obtained by bio-inspired mineralization of self-assembling Type I collagen matrix with magnesium-doped-hydroxyapatite nanophase, towards a biomimetic mineralized 3D scaffolds (MgHA/Coll) with excellent compositional and structural mimicry of bone tissue. To this aim, two different crosslinking mechanisms in terms of pre-ribose glycation (before freeze drying) and post-ribose glycation (after freeze drying) were investigated. The obtained results explicate that with controlled freeze-drying, highly anisotropic porous structures with opportune macro-micro porosity are obtained. The physical-chemical features of the scaffolds characterized by XRD, FTIR, ICP and TGA demonstrated structural mimicry analogous to the native bone. The influence of ribose greatly assisted in decreasing solubility and increased enzymatic resistivity of the scaffolds. In addition, enhanced mechanical behaviour in response to compressive forces was achieved. Preliminary cell culture experiments reported good cytocompatibility with extensive cell adhesion, proliferation and colonization. Overall, scaffolds developed by pre-ribose glycation process are preferred, as the related crosslinking technique is more facile and robust to obtain functional scaffolds. As a proof of concept, we have demonstrated that ribose crosslinking is cost-effective, safe and functionally effective. This study also offers new insights and opportunities in developing promising scaffolds for bone tissue engineering. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. In Vivo Osteogenic Potential of Biomimetic Hydroxyapatite/Collagen Microspheres: Comparison with Injectable Cement Pastes

    Science.gov (United States)

    Manzanares, Maria-Cristina; Ginebra, Maria-Pau; Franch, Jordi

    2015-01-01

    The osteogenic capacity of biomimetic calcium deficient hydroxyapatite microspheres with and without collagen obtained by emulsification of a calcium phosphate cement paste has been evaluated in an in vivo model, and compared with an injectable calcium phosphate cement with the same composition. The materials were implanted into a 5 mm defect in the femur condyle of rabbits, and bone formation was assessed after 1 and 3 months. The histological analysis revealed that the cements presented cellular activity only in the margins of the material, whereas each one of the individual microspheres was covered with osteogenic cells. Consequently, bone ingrowth was enhanced by the microspheres, with a tenfold increase compared to the cement, which was associated to the higher accessibility for the cells provided by the macroporous network between the microspheres, and the larger surface area available for osteoconduction. No significant differences were found in terms of bone formation associated with the presence of collagen in the materials, although a more extensive erosion of the collagen-containing microspheres was observed. PMID:26132468

  18. Biomimetic synthesis of hybrid hydroxyapatite nanoparticles using nanogel template for controlled release of bovine serum albumin.

    Science.gov (United States)

    Qin, Jinli; Zhong, Zhenyu; Ma, Jun

    2016-05-01

    A biomimetic method was used to prepare hybrid hydroxyapatite (HAP) nanoparticles with chitosan/polyacrylic acid (CS-PAA) nanogel. The morphology, structure, crystallinity, thermal properties and biocompatibility of the obtained hybrid nanogel-HAP nanoparticles have been characterized. In addition, bovine serum albumin (BSA) was used as a model protein to study the loading and release behaviors of the hybrid nanogel-HAP nanoparticles. The results indicated that the obtained HAP nanoparticles were agglomerated and the nanogel could regulate the formation of HAP. When the nanogel concentration decreased, different HAP crystal shapes and agglomerate structures were obtained. The loading amount of BSA reached 67.6 mg/g for the hybrid nanoparticles when the mineral content was 90.4%, which decreased when the nanogel concentration increased. The release profile of BSA was sustained in neutral buffer. Meanwhile, an initial burst release was found at pH 4.5 due to the desorption of BSA from the surface, followed by a slow release. The hemolysis percentage of the hybrid nanoparticles was close to the negative control, and these particles were non-toxic to bone marrow stromal stem cells. The results suggest that these hybrid nanogel-HAP nanoparticles are promising candidate materials for biocompatible drug delivery systems. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. In Vivo Osteogenic Potential of Biomimetic Hydroxyapatite/Collagen Microspheres: Comparison with Injectable Cement Pastes.

    Directory of Open Access Journals (Sweden)

    Erika Cuzmar

    Full Text Available The osteogenic capacity of biomimetic calcium deficient hydroxyapatite microspheres with and without collagen obtained by emulsification of a calcium phosphate cement paste has been evaluated in an in vivo model, and compared with an injectable calcium phosphate cement with the same composition. The materials were implanted into a 5 mm defect in the femur condyle of rabbits, and bone formation was assessed after 1 and 3 months. The histological analysis revealed that the cements presented cellular activity only in the margins of the material, whereas each one of the individual microspheres was covered with osteogenic cells. Consequently, bone ingrowth was enhanced by the microspheres, with a tenfold increase compared to the cement, which was associated to the higher accessibility for the cells provided by the macroporous network between the microspheres, and the larger surface area available for osteoconduction. No significant differences were found in terms of bone formation associated with the presence of collagen in the materials, although a more extensive erosion of the collagen-containing microspheres was observed.

  20. Chondroitin sulfate template-mediated biomimetic synthesis of nano-flake hydroxyapatite

    Science.gov (United States)

    He, Dan; Xiao, Xiufeng; Liu, Fang; Liu, Rongfang

    2008-11-01

    By Ca(NO 3) 2·4H 2O and (NH 4) 3PO 4·3H 2O as reagents and chondroitin sulfate (ChS) as a template, nano-flake hydroxyapatite (HA) is synthesized using a biomimetic method according to the biomineralization theory. HA crystals obtained are characterized in crystalline phase, microstructure, chemical composition and morphology by X-ray diffraction (XRD), Fourier transform infrared spectroscope (FTIR), transmission electron microscopy (TEM) and elemental analysis respectively. UV-vis spectrum is adopted to investigate interactions between functional groups ChS and HA. The results show that HA crystal nucleation and growth take place in chemical interactions between HA crystals and ChS as a template. And elemental analysis indicates that obtained HA contains a small amount of ChS. Furthermore, ChS concentration significantly affects the morphology of HA crystals. Staple-fiber-like HA crystals can be obtained at a low concentration in ChS, and flake-like HA crystals synthesized at a high concentration (≥0.5 wt.%) of ChS as a template.

  1. Chondroitin sulfate template-mediated biomimetic synthesis of nano-flake hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    He Dan; Xiao Xiufeng; Liu Fang [College of Chemistry and Materials Science, Fujian Normal University, Fuzhou 350007 (China); Liu Rongfang [College of Chemistry and Materials Science, Fujian Normal University, Fuzhou 350007 (China)], E-mail: rfliu@vip.sina.com

    2008-11-15

    By Ca(NO{sub 3}){sub 2}.4H{sub 2}O and (NH{sub 4}){sub 3}PO{sub 4}.3H{sub 2}O as reagents and chondroitin sulfate (ChS) as a template, nano-flake hydroxyapatite (HA) is synthesized using a biomimetic method according to the biomineralization theory. HA crystals obtained are characterized in crystalline phase, microstructure, chemical composition and morphology by X-ray diffraction (XRD), Fourier transform infrared spectroscope (FTIR), transmission electron microscopy (TEM) and elemental analysis respectively. UV-vis spectrum is adopted to investigate interactions between functional groups ChS and HA. The results show that HA crystal nucleation and growth take place in chemical interactions between HA crystals and ChS as a template. And elemental analysis indicates that obtained HA contains a small amount of ChS. Furthermore, ChS concentration significantly affects the morphology of HA crystals. Staple-fiber-like HA crystals can be obtained at a low concentration in ChS, and flake-like HA crystals synthesized at a high concentration ({>=}0.5 wt.%) of ChS as a template.

  2. Preparation and characterization of hydroxyapatite/chondroitin sulfate composites by biomimetic synthesis

    International Nuclear Information System (INIS)

    Xiao Xiufeng; He Dan; Liu Fang; Liu Rongfang

    2008-01-01

    Based on the principles of biomineralization, flakelike hydroxyapatite/chondroitin sulfate composites were synthesized through biomimetic method using Ca(NO 3 ) 2 .4H 2 O and (NH 4 ) 3 PO 4 .3H 2 O as reagents and chondroitin sulfate as template. The crystalline phase, microstructure, chemical composition, morphology and thermal behavior of the composites obtained in the experiment were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscope (FTIR), transmission electron microscope (TEM), Thermogravimetry-Differential thermal analyzer (TG-DTA) and Elemental analyzer, respectively. The interaction between the functional groups of ChS and HA was investigated by electrical conductivity and UV-vis spectrum. The results demonstrate that the as-prepared powders with small amount of carbonate have the component similar to human bone. It can be concluded that the nucleation and growth of HA crystals occurred through the chemical interactions between the HA crystals and preorganized functional groups of the ChS template. Furthermore, the concentration of ChS significantly affects the morphology of the composites. Short fiberlike crystals could be obtained at a low concentration of ChS, but flakelike crystals could be synthesized using a high concentration (≥0.5 wt%) of ChS as template

  3. Preparation and characterization of hydroxyapatite/chondroitin sulfate composites by biomimetic synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Xiao Xiufeng; He Dan; Liu Fang [College of Chemistry and Materials Science, Fujian Normal University, Fujian, Fuzhou 350007 (China); Liu Rongfang [College of Chemistry and Materials Science, Fujian Normal University, Fujian, Fuzhou 350007 (China)], E-mail: rfliu@vip.sina.com

    2008-12-20

    Based on the principles of biomineralization, flakelike hydroxyapatite/chondroitin sulfate composites were synthesized through biomimetic method using Ca(NO{sub 3}){sub 2}.4H{sub 2}O and (NH{sub 4}){sub 3}PO{sub 4}.3H{sub 2}O as reagents and chondroitin sulfate as template. The crystalline phase, microstructure, chemical composition, morphology and thermal behavior of the composites obtained in the experiment were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscope (FTIR), transmission electron microscope (TEM), Thermogravimetry-Differential thermal analyzer (TG-DTA) and Elemental analyzer, respectively. The interaction between the functional groups of ChS and HA was investigated by electrical conductivity and UV-vis spectrum. The results demonstrate that the as-prepared powders with small amount of carbonate have the component similar to human bone. It can be concluded that the nucleation and growth of HA crystals occurred through the chemical interactions between the HA crystals and preorganized functional groups of the ChS template. Furthermore, the concentration of ChS significantly affects the morphology of the composites. Short fiberlike crystals could be obtained at a low concentration of ChS, but flakelike crystals could be synthesized using a high concentration ({>=}0.5 wt%) of ChS as template.

  4. Microwave-induced biomimetic approach for hydroxyapatite coatings of chitosan scaffolds.

    Science.gov (United States)

    Kaynak Bayrak, Gökçe; Demirtaş, T Tolga; Gümüşderelioğlu, Menemşe

    2017-02-10

    Simulated body fluid (SBF) can form calcium phosphates on osteoinductive materials, so it is widely used for coating of bone scaffolds to mimic natural extracellular matrix (ECM). However, difficulties of bulk coating in 3D scaffolds and the necessity of long process times are the common problems for coating with SBF. In the present study, a microwave-assisted process was developed for rapid and internal coating of chitosan scaffolds. The scaffolds were fabricated as superporous hydrogel (SPH) by combining microwave irradiation and gas foaming methods. Then, they were immersed into 10x  SBF-like solution and homogenous bone-like hydroxyapatite (HA) coating was achieved by microwave treatment at 600W without the need of any nucleating agent. Cell culture studies with MC3T3-E1 preosteoblasts showed that microwave-assisted biomimetic HA coating process could be evaluated as an efficient and rapid method to obtain composite scaffolds for bone tissue engineering. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Biomimetics

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    Biomimetics is the field of scientific endeavour, which attempts to design systems and syn- thesise materials through ... natural systems with a view to achieve analogous synthetic design and manufacture. On the ..... Industrial production.

  6. Obtaining hydroxyapatite coatings on titanium by the biomimetic method; Obtencion de recubrimientos de hidroxiapatita sobre titanio mediante el metodo biomimetico

    Energy Technology Data Exchange (ETDEWEB)

    Paz, A.; Martin, Y.; Pazos, L. M.; Parodi, M. B.; Ybarra, G. O.; Gonzalez, J. E.

    2011-07-01

    In this work, a study about the deposition of hydroxyapatite on a titanium substrate employing the biomimetic method is presented. A solution with high content of calcium and phosphorus (SCS) was used. In addition, activation of titanium with hydrogen peroxide and hydrochloric acid and a subsequent heat treatment was performed. The characterization of materials used and the coating obtained was carried out by Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX). As a result of the activation processes a hydrated titanium oxide was formed. On the active surface, a coating of hydroxyapatite was obtained after a period of 24 h, which has a thickness of about 2-4 {mu}m. (Author) 21 refs.

  7. Biomimetic nanocomposites of carboxymethyl cellulose-hydroxyapatite: novel three dimensional load bearing bone grafts.

    Science.gov (United States)

    Garai, Subhadra; Sinha, Arvind

    2014-03-01

    An innovative biomimetic synthesis of novel three dimensional micro/macro porous carboxymethyl cellulose (CMC)-hydroxyapatite (HA) nanocomposites having four systematically different compositions has been established for its possible application as a load bearing synthetic bone graft. Our process, being in situ, involves a simple and cost effective route akin to a matrix mediated biomineralization process. Developed synthesis route not only controls the size of HA particles in the range of 15-50 nm, embedded in CMC matrix, but also assists in the formation of a mechanically strong three dimensional nanocomposite structures due to physical cross linking of HA impregnated CMC matrix. The process does not involve any toxic cross linker and works at near ambient conditions. The nanocomposites are systematically structurally and mechanically characterized using various techniques like scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform IR (FTIR), solid state (13)C nuclear magnetic resonance ((13)C NMR), thermo-gravimetric analysis (TGA) and Universal mechanical test. It reveals that the ionic/polar or electrostatic interactions are the main driving force for formation of load bearing three dimensional nanocomposites via a process similar to matrix mediated biomineralization. Compressive strength and compressive modulus of nanocomposites, being in the range of 1.74-12 MPa and 157-330 MPa, respectively, meet the desired range of compressive strength for the synthetic grafts used in cancellous bone. An increase in the compressive strength with increase in the porosity has been an interesting observation in the present study. In vitro cytotoxicity of the synthesized nanocomposites has been evaluated using bone marrow mesenchymal stem cells (BMSC) isolated from Wistar rat. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Sectioning studies of biomimetic collagen-hydroxyapatite coatings on Ti-6Al-4V substrates using focused ion beam

    Science.gov (United States)

    Hu, Changmin; Yu, Le; Wei, Mei

    2018-06-01

    A biomimetic bone-like collagen-hydroxyapatite (Col-HA) composite coating was formed on a surface-treated Ti-6Al-4V alloy substrate via simultaneous collagen self-assembly and hydroxyapatite nucleation. The coating process has been carried out by immersing sand-blasted, acid-etched and UV irradiated Ti-6Al-4V alloy in type I collagen-containing modified simulated body fluid (m-SBF). The surface morphology and phase composition of the coating were characterized using various techniques. More importantly, dual-beam FIB/SEMs with either gallium ion source (GFIB) or xenon plasma ion source (PFIB) were used to investigate the cross-sectional features of the biomimetic Col-HA composite coating in great details. As a result, the cross-sectional images and thin transmission electron microscopy (TEM) specimens were successfully obtained from the composite coating with no obvious damages or milling ion implantations. Both the cross-sectional SEM and TEM results have confirmed that the Col-HA coating demonstrates a similar microstructure to that of pure HA coating with homogeneously distributed elements across the whole cross section. Both coatings consist of a uniform, crack-free gradient structure with a dense layer adjacent to the interface between the Ti-6Al-4V substrate and the coating facilitating a strong bonding, while a porous structure at the coating surface aiding cell attachment.

  9. Biomimetic hierarchical growth and self-assembly of hydroxyapatite/titania nanocomposite coatings and their biomedical applications

    International Nuclear Information System (INIS)

    Nathanael, A. Joseph; Im, Young Min; Oh, Tae Hwan; Yuvakkumar, R.; Mangalaraj, D.

    2015-01-01

    Graphical abstract: - Highlights: • Novel ‘bowtie’ like biomimetic HA/TiO 2 nanocomposite coatings were prepared. • Simple sol–gel method was used to achieve this novel structure. • Details analysis confirms the formation of bowtie like structure in many ways. • Their functional analysis showed their enhanced activity for biomedical application. - Abstract: This article describes a systematic study of the biomimetic hierarchical growth of hydroxyapatite (HA)/titania (TiO 2 ) nanocomposite layered coatings applied by a simple sol–gel dip coating method. Highly stable HA and TiO 2 sols were prepared prior to inducing biomimetic hierarchical growth. Initially, the samples formed a small leaf like structure; however, increasing the dipping cycle resulted in formation of an elongated seed-like structure. Increasing the number of dipping cycles further resulted in a ‘bowtie’ or straw-bale like nanowire structure with a length of 500 nm and a width of 100 nm. Each nanowire like structure had a width of very few nanometers. The crystalline structures, micro/nano structures and surface properties of the coatings were characterized by X-ray diffraction, scanning electron microscopy and atomic force microscopy respectively. In vitro cellular assays revealed that the growth of the cells in the ‘bowtie’ like structure improved over other samples

  10. Biomimetic hierarchical growth and self-assembly of hydroxyapatite/titania nanocomposite coatings and their biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Nathanael, A. Joseph, E-mail: ajosephnc@yahoo.com [Department of Nano, Medical and Polymer Materials, Yeungnam University, Gyeongsan (Korea, Republic of); Im, Young Min [Department of Nano, Medical and Polymer Materials, Yeungnam University, Gyeongsan (Korea, Republic of); Oh, Tae Hwan, E-mail: taehwanoh@ynu.ac.kr [Department of Nano, Medical and Polymer Materials, Yeungnam University, Gyeongsan (Korea, Republic of); Yuvakkumar, R. [Department of Nanomaterials Engineering, Chungnam National University, Daejeon (Korea, Republic of); Mangalaraj, D. [Department of Nanoscience and Technology, Bharathiar University, Coimbatore (India)

    2015-03-30

    Graphical abstract: - Highlights: • Novel ‘bowtie’ like biomimetic HA/TiO{sub 2} nanocomposite coatings were prepared. • Simple sol–gel method was used to achieve this novel structure. • Details analysis confirms the formation of bowtie like structure in many ways. • Their functional analysis showed their enhanced activity for biomedical application. - Abstract: This article describes a systematic study of the biomimetic hierarchical growth of hydroxyapatite (HA)/titania (TiO{sub 2}) nanocomposite layered coatings applied by a simple sol–gel dip coating method. Highly stable HA and TiO{sub 2} sols were prepared prior to inducing biomimetic hierarchical growth. Initially, the samples formed a small leaf like structure; however, increasing the dipping cycle resulted in formation of an elongated seed-like structure. Increasing the number of dipping cycles further resulted in a ‘bowtie’ or straw-bale like nanowire structure with a length of 500 nm and a width of 100 nm. Each nanowire like structure had a width of very few nanometers. The crystalline structures, micro/nano structures and surface properties of the coatings were characterized by X-ray diffraction, scanning electron microscopy and atomic force microscopy respectively. In vitro cellular assays revealed that the growth of the cells in the ‘bowtie’ like structure improved over other samples.

  11. Biomimetics

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    Abstract. The well-organised multifunctional structures, systems and biogenic materials found in nature have attracted the interest of scientists working in many disciplines. The efforts have resulted in the development of a new and rapidly growing field of scientific effort called biomimetics. In this article we present a.

  12. Calcination of Rod-like Hydroxyapatite Nanocrystals with an Anti-sintering Agent Surrounding the Crystals

    International Nuclear Information System (INIS)

    Okada, M.; Furuzono, T.

    2007-01-01

    Sintering-free nanocrystals of calcined hydroxyapatite (HAp) having a rod-like morphology were fabricated by calcination at 800 deg. C for 1 h with an anti-sintering agent surrounding original HAp particles and the agent was subsequently removed after calcination. The original HAp particles having a rod-like morphology with a size ranging from 30 to 80 nm (short axis) and 300 to 500 nm (long axis) were prepared by wet chemical process, and poly(acrylic acid, calcium salt) (PAA-Ca) was used as the anti-sintering agent. In the case of calcination without additives, the mean size of HAp crystals dispersed in an ethanol medium increased by about 4 times and the specific surface area of the crystals exhibited a 25% decrease compared to those of the original HAp particles because of calcination-induced sintering among the crystals. On the other hand, the HAp crystals calcined with the anti-sintering agent, PAA-Ca, could be dispersed in an ethanol medium at the same size as the original particles, and they preserved the specific surface area after calcination. These results indicate that PAA-Ca and/or its thermally decomposed product, CaO, surrounded the HAp particles and protected them against calcination-induced sintering during calcination. The HAp crystals calcined with PAA-Ca showed high crystallinity, and no other calcium phosphate phases could be detected after washing with water

  13. Influence of fluorine substitution on the morphology and structure of hydroxyapatite nanocrystals prepared by hydrothermal method

    International Nuclear Information System (INIS)

    Joseph Nathanael, A.; Mangalaraj, D.; Hong, S.I.; Masuda, Y.; Rhee, Y.H.; Kim, H.W.

    2013-01-01

    Hydroxyapatite (HAp) nanocrystals with different levels of fluorine substitution (P/F = 0, 6, 4 and 2) on the OH sites were produced via hydrothermal method. The fluorine substitution was found to alter the morphology of crystals appreciably. The aspect ratio and the crystallinity of HAp crystals increased with increasing fluorine substitution. The presence of broad ring and hallow ring patterns in electron diffraction suggests the low-crystalline nature of HAp crystals. With increasing fluorine substitution, the diffraction patterns exhibited discrete rings and numerous diffraction spots, implying the increased crystallinity. Raman spectra from the HAp nanoparticles also support the less-crystalline nature of the pristine HAp and the enhanced crystallization by fluorine substitution. In HAp crystals processed with no fluorine substitution, surface energy and planar Ca 2+ density are less sensitive to the crystallographic orientation because of its low-crystalline nature, favoring equi-axed or slightly elongated particles. The addition of fluorine apparently increased the crystallinity, enhancing the orientation dependent growth and accordingly the aspect ratio. Osteoblast proliferation was observed to be enhanced by fluorine substitution in HAp. In vitro biological data support that the excellent osteoblastic cell viability and functional activity of the fluoridated apatite. -- Highlights: ► Fluorapatite nanorods were produced hydrothermally with different fluorine content. ► Fluorine substitution was found to alter the morphology of crystals appreciably. ► It enhances the crystallinity, orientation dependent growth and hence aspect ratio. ► In vitro cellular analysis shows excellent cell viability of the fluorapatite.

  14. Surface microstructure and cell biocompatibility of silicon-substituted hydroxyapatite coating on titanium substrate prepared by a biomimetic process

    International Nuclear Information System (INIS)

    Zhang Erlin; Zou Chunming; Yu Guoning

    2009-01-01

    Silicon-substituted hydroxyapatite (Si-HA) coatings with 0.14 to 1.14 at.% Si on pure titanium were prepared by a biomimetic process. The microstructure characterization and the cell compatibility of the Si-HA coatings were studied in comparison with that of hydroxyapatite (HA) coating prepared in the same way. The prepared Si-HA coatings and HA coating were only partially crystallized or in nano-scaled crystals. The introduction of Si element in HA significantly reduced P and Ca content, but densified the coating. The atom ratio of Ca to (P + Si) in the Si-HA coatings was in a range of 1.61-1.73, increasing slightly with an increase in the Si content. FTIR results displayed that Si entered HA in a form of SiO 4 unit by substituting for PO 4 unit. The cell attachment test showed that the HA and Si-HA coatings exhibited better cell response than the uncoated titanium, but no difference was observed in the cell response between the HA coating and the Si-HA coatings. Both the HA coating and the Si-HA coatings demonstrated a significantly higher cell growth rate than the uncoated pure titanium (p < 0.05) in all incubation periods while the Si-HA coating exhibited a significantly higher cell growth rate than the HA coating (p < 0.05). Si-HA with 0.42 at.% Si presented the best cell biocompatibility in all of the incubation periods. It was suggested that the synthesis mode of HA and Si-HA coatings in a simulated body environment in the biomimetic process contribute significantly to good cell biocompatibility

  15. Effect of osteogenesis imperfecta mutations in tropocollagen molecule on strength of biomimetic tropocollagen-hydroxyapatite nanocomposites

    Science.gov (United States)

    Dubey, Devendra K.; Tomar, Vikas

    2010-01-01

    Osteogenesis Imperfecta (OI) is a genetic disorder that affects cellular synthesis of Type-I collagen fibrils and causes extreme bone fragility. This study reports the effects of OI mutations in Tropocollagen (TC) molecules on strength of model Tropocollagen-Hydroxyapatite biomaterials with two different mineral [hydroxyapatite (HAP)] distributions using three dimensional atomistic simulations. Results show that the effect of TC mutations on the strength of TC-HAP biomaterials is insignificant. Instead, change in mineral distribution showed significant impact on the overall strength of TC-HAP biomaterials. Study suggests that TC mutations manifest themselves by changing the mineral distribution during hydroxyapatite growth and nucleation period.

  16. Evaluation of zinc-doped mesoporous hydroxyapatite microspheres for the construction of a novel biomimetic scaffold optimized for bone augmentation

    Directory of Open Access Journals (Sweden)

    Yu W

    2017-03-01

    Full Text Available Weilin Yu,1,* Tuan-Wei Sun,2,3,* Chao Qi,2,3 Zhenyu Ding,1 Huakun Zhao,1 Shichang Zhao,1 Zhongmin Shi,1 Ying-Jie Zhu,2,3 Daoyun Chen,1 Yaohua He1,4 1Department of Orthopedics, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, 2State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 3University of Chinese Academy of Sciences, Beijing, 4School of Biomedical Engineering, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China *These authors contributed equally to this work Abstract: Biomaterials with high osteogenic activity are desirable for sufficient healing of bone defects resulting from trauma, tumor, infection, and congenital abnormalities. Synthetic materials mimicking the structure and composition of human trabecular bone are of considerable potential in bone augmentation. In the present study, a zinc (Zn-doped mesoporous hydroxyapatite microspheres (Zn-MHMs/collagen scaffold (Zn-MHMs/Coll was developed through a lyophilization fabrication process and designed to mimic the trabecular bone. The Zn-MHMs were synthesized through a microwave-hydrothermal method by using creatine phosphate as an organic phosphorus source. Zn-MHMs that consist of hydroxyapatite nanosheets showed relatively uniform spherical morphology, mesoporous hollow structure, high specific surface area, and homogeneous Zn distribution. They were additionally investigated as a drug nanocarrier, which was efficient in drug delivery and presented a pH-responsive drug release behavior. Furthermore, they were incorporated into the collagen matrix to construct a biomimetic scaffold optimized for bone tissue regeneration. The Zn-MHMs/Coll scaffolds showed an interconnected pore structure in the range of 100–300 µm and a sustained release of Zn ions. More importantly, the Zn-MHMs/Coll scaffolds could enhance the osteogenic differentiation

  17. Influence of fluorine substitution on the morphology and structure of hydroxyapatite nanocrystals prepared by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Joseph Nathanael, A., E-mail: ajosephnc@yahoo.com [Department of Nanomaterials Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Thin Film and Nanomaterials Laboratory, Department of Physics, Bharathiar University, Coimbatore 641 046 (India); Mangalaraj, D., E-mail: dmraj800@yahoo.com [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641 046 (India); Hong, S.I., E-mail: sihong@cnu.ac.kr [Thin Film and Nanomaterials Laboratory, Department of Physics, Bharathiar University, Coimbatore 641 046 (India); Masuda, Y. [National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560 (Japan); Rhee, Y.H.; Kim, H.W. [Department of Microbiology, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2013-01-15

    Hydroxyapatite (HAp) nanocrystals with different levels of fluorine substitution (P/F = 0, 6, 4 and 2) on the OH sites were produced via hydrothermal method. The fluorine substitution was found to alter the morphology of crystals appreciably. The aspect ratio and the crystallinity of HAp crystals increased with increasing fluorine substitution. The presence of broad ring and hallow ring patterns in electron diffraction suggests the low-crystalline nature of HAp crystals. With increasing fluorine substitution, the diffraction patterns exhibited discrete rings and numerous diffraction spots, implying the increased crystallinity. Raman spectra from the HAp nanoparticles also support the less-crystalline nature of the pristine HAp and the enhanced crystallization by fluorine substitution. In HAp crystals processed with no fluorine substitution, surface energy and planar Ca{sup 2+} density are less sensitive to the crystallographic orientation because of its low-crystalline nature, favoring equi-axed or slightly elongated particles. The addition of fluorine apparently increased the crystallinity, enhancing the orientation dependent growth and accordingly the aspect ratio. Osteoblast proliferation was observed to be enhanced by fluorine substitution in HAp. In vitro biological data support that the excellent osteoblastic cell viability and functional activity of the fluoridated apatite. -- Highlights: Black-Right-Pointing-Pointer Fluorapatite nanorods were produced hydrothermally with different fluorine content. Black-Right-Pointing-Pointer Fluorine substitution was found to alter the morphology of crystals appreciably. Black-Right-Pointing-Pointer It enhances the crystallinity, orientation dependent growth and hence aspect ratio. Black-Right-Pointing-Pointer In vitro cellular analysis shows excellent cell viability of the fluorapatite.

  18. Direct Scaffolding of Biomimetic Hydroxyapatite-gelatin Nanocomposites using Aminosilane Cross-linker for Bone Regeneration

    OpenAIRE

    Chiu, Chi-Kai; Ferreira, Joao; Luo, Tzy-Jiun M.; Geng, Haixia; Lin, Feng-Chang; Ko, Ching-Chang

    2012-01-01

    Hydroxyapatite-gelatin modified siloxane (GEMOSIL) nanocomposite was developed by coating, kneading and hardening processes to provide formable scaffolding for alloplastic graft applications. The present study aims to characterize scaffolding formability and mechanical properties of GEMOSIL, and to test the in vitro and in vivo biocompatibility of GEMOSIL. Buffer Solution initiated formable paste followed by the sol-gel reaction led to a final hardened composite. Results showed the adequate c...

  19. Use of Raman microscopy and multivariate data analysis to observe the biomimetic growth of carbonated hydroxyapatite on bioactive glass.

    Science.gov (United States)

    Seah, Regina K H; Garland, Marc; Loo, Joachim S C; Widjaja, Effendi

    2009-02-15

    In the present contribution, the biomimetic growth of carbonated hydroxyapatite (HA) on bioactive glass were investigated by Raman microscopy. Bioactive glass samples were immersed in simulated body fluid (SBF) buffered solution at pH 7.40 up to 17 days at 37 degrees C. Raman microscopy mapping was performed on the bioglass samples immersed in SBF solution for different periods of time. The collected data was then analyzed using the band-target entropy minimization technique to extract the observable pure component Raman spectral information. In this study, the pure component Raman spectra of the precursor amorphous calcium phosphate, transient octacalcium phosphate, and matured HA were all recovered. In addition, pure component Raman spectra of calcite, silica glass, and some organic impurities were also recovered. The resolved pure component spectra were fit to the normalized measured Raman data to provide the spatial distribution of these species on the sample surfaces. The current results show that Raman microscopy and multivariate data analysis provide a sensitive and accurate tool to characterize the surface morphology, as well as to give more specific information on the chemical species present and the phase transformation of phosphate species during the formation of HA on bioactive glass.

  20. Biomimetic scaffolds based on hydroxyapatite nanorod/poly(D,L) lactic acid with their corresponding apatite-forming capability and biocompatibility for bone-tissue engineering.

    Science.gov (United States)

    Nga, Nguyen Kim; Hoai, Tran Thanh; Viet, Pham Hung

    2015-04-01

    This study presents a facile synthesis of biomimetic hydroxyapatite nanorod/poly(D,L) lactic acid (HAp/PDLLA) scaffolds with the use of solvent casting combined with a salt-leaching technique for bone-tissue engineering. Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy were used to observe the morphologies, pore structures of synthesized scaffolds, interactions between hydroxyapatite nanorods and poly(D,L) lactic acid, as well as the compositions of the scaffolds, respectively. Porosity of the scaffolds was determined using the liquid substitution method. Moreover, the apatite-forming capability of the scaffolds was evaluated through simulated body fluid (SBF) incubation tests, whereas the viability, attachment, and distribution of human osteoblast cells (MG 63 cell line) on the scaffolds were determined through alamarBlue assay and confocal laser microscopy after nuclear staining with 4',6-diamidino-2-phenylindole and actin filaments of a cytoskeleton with Oregon Green 488 phalloidin. Results showed that hydroxyapatite nanorod/poly(D,L) lactic acid scaffolds that mimic the structure of natural bone were successfully produced. These scaffolds possessed macropore networks with high porosity (80-84%) and mean pore sizes ranging 117-183 μm. These scaffolds demonstrated excellent apatite-forming capabilities. The rapid formation of bone-like apatites with flower-like morphology was observed after 7 days of incubation in SBFs. The scaffolds that had a high percentage (30 wt.%) of hydroxyapatite demonstrated better cell adhesion, proliferation, and distribution than those with low percentages of hydroxyapatite as the days of culture increased. This work presented an efficient route for developing biomimetic composite scaffolds, which have potential applications in bone-tissue engineering. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Evaluation in vitro and in vivo of biomimetic hydroxyapatite coated on titanium dental implants

    International Nuclear Information System (INIS)

    Rigo, E.C.S.; Boschi, A.O.; Yoshimoto, M.; Allegrini, S.; Konig, B.; Carbonari, M.J.

    2004-01-01

    Among several materials used as dental implants, metals present relatively high tensile strengths. Although metals are biotolerable, they do not adhere to bone tissues. On the other hand, bioactive ceramics are known to chemically bind to bone tissues, but they are not enough mechanically resistant to tension stresses. To overcome this drawback, biotolerable metals can be coated with bioactive ceramics. Various methods can be employed for coating ceramic layers on metal substrates, among them ion sputtering, plasma spray, sol-gel, electrodeposition and a biomimetic process [E.C.S. Rigo, L.C. Oliveira, L.A. Santos, A.O. Boschi, R.G. Carrodeguas. Implantes metalicos recobertos com hidroxiapatita. Revista de Engenharia Biomedica, vol. 15 (1999), numeros 1-2, 21-29. Rio de Janeiro]. The aim of this work was to study the effect of the substitution of G glass, employed in the conventional biomimetic method during the nucleation stage, by a solution of sodium silicate (SS) on the chemical and morphological characteristics, and the adhesion of biomimetic coatings deposited on Ti implants. The obtained coatings were analyzed by diffuse reflectance FTIR spectroscopy (DRIFT) and scanning electron microscopy (SEM). Titanium implants were immersed in synthetic body fluid (SBF) and SS. All implants were left inside an incubator at 37 deg. C for 7 days, followed by immersion in 1.5 SBF and taken back to the incubator for additional 6 days at 37 deg. C. The 1.5 SBF were refreshed every 2 days. At the end of the treatment, the implants were washed in distilled and deionized water and dried at room temperature. To check the osseointegration, titanium implants coated with biomimetic method were inserted in rabbit's tibia, remaining there for 8 weeks. During the healing period, polyfluorochrome sequential labeling was inoculated in the rabbits to determine the period of bone remodeling. Results from DRIFT and SEM showed that, for all processing variants employed, a HA coating was

  2. The Development of Biomimetic Spherical Hydroxyapatite/Polyamide 66 Biocomposites as Bone Repair Materials

    Directory of Open Access Journals (Sweden)

    Xuesong Zhang

    2014-01-01

    Full Text Available A novel biomedical material composed of spherical hydroxyapatite (s-HA and polyamide 66 (PA biocomposite (s-HA/PA was prepared, and its composition, mechanical properties, and cytocompatibility were characterized and evaluated. The results showed that HA distributed uniformly in the s-HA/PA matrix. Strong molecule interactions and chemical bonds were presented between the s-HA and PA in the composites confirmed by IR and XRD. The composite had excellent compressive strength in the range between 95 and 132 MPa, close to that of natural bone. In vitro experiments showed the s-HA/PA composite could improve cell growth, proliferation, and differentiation. Therefore, the developed s-HA/PA composites in this study might be used for tissue engineering and bone repair.

  3. Biomimetic composite microspheres of collagen/chitosan/nano-hydroxyapatite: In-situ synthesis and characterization.

    Science.gov (United States)

    Teng, Shu-Hua; Liang, Mian-Hui; Wang, Peng; Luo, Yong

    2016-01-01

    The collagen/chitosan/hydroxyapatite (COL/CS/HA) composite microspheres with a good spherical form and a high dispersity were successfully obtained using an in-situ synthesis method. The FT-IR and XRD results revealed that the inorganic phase in the microspheres was crystalline HA containing carbonate ions. The morphology of the composite microspheres was dependent on the HA content, and a more desirable morphology was achieved when 20 wt.% HA was contained. The composite microspheres exhibited a narrow particle distribution, most of which ranged from 5 to 10 μm. In addition, the needle-like HA nano-particles were uniformly distributed in the composite microspheres, and their crystallinity and crystal size decreased with the HA content. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. X-ray photoelectron spectroscopy study of the growth kinetics of biomimetically grown hydroxyapatite thin-film coatings

    International Nuclear Information System (INIS)

    McLeod, K.; Kumar, S.; Dutta, N.K.; Smart, R.St.C.; Voelcker, N.H.; Anderson, G.I.

    2010-01-01

    Hydroxyapatite (HA) thin-film coatings grown biomimetically using simulated body fluid (SBF) are desirable for a range of applications such as improved fixation of fine- and complex-shaped orthopedic and dental implants, tissue engineering scaffolds and localized and sustained drug delivery. There is a dearth of knowledge on two key aspects of SBF-grown HA coatings: (i) the growth kinetics over short deposition periods, hours rather than weeks; and (ii) possible difference between the coatings deposited with and without periodic SBF replenishment. A study centred on these aspects is reported. X-ray photoelectron spectroscopy (XPS) has been used to study the growth kinetics of SBF-grown HA coatings for deposition periods ranging from 0.5 h to 21 days. The coatings were deposited with and without periodic replenishment of SBF. The XPS studies revealed that: (i) a continuous, stable HA coating fully covered the titanium substrate after a growth period of 13 h without SBF replenishment; (ii) thicker HA coatings about 1 μm in thickness resulted after a growth period of 21 days, both with and without SBF replenishment; and (iii) the Ca/P ratio at the surface of the HA coating was significantly lower than that in its bulk. No significant difference between HA grown with and without periodic replenishment of SBF was found. The coatings were determined to be carbonated, a characteristic desirable for improved implant fixation. The atomic force and scanning electron microscopies results suggested that heterogeneous nucleation and growth are the primary deposition mode for these coatings. Primary osteoblast cell studies demonstrated the biocompatibility of these coatings, i.e., osteoblast colony coverage of approximately 80%, similar to the control substrate (tissue culture polystyrene).

  5. X-ray photoelectron spectroscopy study of the growth kinetics of biomimetically grown hydroxyapatite thin-film coatings

    Energy Technology Data Exchange (ETDEWEB)

    McLeod, K. [Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA 5095 (Australia); Kumar, S., E-mail: sunil.kumar@unisa.edu.au [Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA 5095 (Australia); Dutta, N.K. [Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA 5095 (Australia); Smart, R.St.C. [Applied Centre for Structural and Synchrotron Studies, University of South Australia, Mawson Lakes, SA 5095 (Australia); Voelcker, N.H. [School of Chemistry, Physics and Earth Sciences, Flinders University of South Australia, GPO Box 2100, Adelaide 5001 (Australia); Anderson, G.I. [School of Veterinary Science, University of Adelaide, Adelaide, SA 5005 (Australia)

    2010-09-15

    Hydroxyapatite (HA) thin-film coatings grown biomimetically using simulated body fluid (SBF) are desirable for a range of applications such as improved fixation of fine- and complex-shaped orthopedic and dental implants, tissue engineering scaffolds and localized and sustained drug delivery. There is a dearth of knowledge on two key aspects of SBF-grown HA coatings: (i) the growth kinetics over short deposition periods, hours rather than weeks; and (ii) possible difference between the coatings deposited with and without periodic SBF replenishment. A study centred on these aspects is reported. X-ray photoelectron spectroscopy (XPS) has been used to study the growth kinetics of SBF-grown HA coatings for deposition periods ranging from 0.5 h to 21 days. The coatings were deposited with and without periodic replenishment of SBF. The XPS studies revealed that: (i) a continuous, stable HA coating fully covered the titanium substrate after a growth period of 13 h without SBF replenishment; (ii) thicker HA coatings about 1 {mu}m in thickness resulted after a growth period of 21 days, both with and without SBF replenishment; and (iii) the Ca/P ratio at the surface of the HA coating was significantly lower than that in its bulk. No significant difference between HA grown with and without periodic replenishment of SBF was found. The coatings were determined to be carbonated, a characteristic desirable for improved implant fixation. The atomic force and scanning electron microscopies results suggested that heterogeneous nucleation and growth are the primary deposition mode for these coatings. Primary osteoblast cell studies demonstrated the biocompatibility of these coatings, i.e., osteoblast colony coverage of approximately 80%, similar to the control substrate (tissue culture polystyrene).

  6. Construction of a fluorescent nanostructured chitosan-hydroxyapatite scaffold by nanocrystallon induced biomimetic mineralization and its cell biocompatibility.

    Science.gov (United States)

    Wang, Guancong; Zheng, Lin; Zhao, Hongshi; Miao, Junying; Sun, Chunhui; Liu, Hong; Huang, Zhen; Yu, Xiaoqiang; Wang, Jiyang; Tao, Xutang

    2011-05-01

    Biomaterial surfaces and their nanostructures can significantly influence cell growth and viability. Thus, manipulating surface characteristics of scaffolds can be a potential strategy to control cell functions for stem cell tissue engineering. In this study, in order to construct a hydroxyapatite (HAp) coated genipin-chitosan conjugation scaffold (HGCCS) with a well-defined HAp nanostructured surface, we have developed a simple and controllable approach that allows construction of a two-level, three-dimensional (3D) networked structure to provide sufficient calcium source and achieve desired mechanical function and mass transport (permeability and diffusion) properties. Using a nontoxic cross-linker (genipin) and a nanocrystallon induced biomimetic mineralization method, we first assembled a layer of HAp network-like nanostructure on a 3D porous chitosan-based framework. X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) analysis confirm that the continuous network-like nanostructure on the channel surface of the HGCCS is composed of crystalline HAp. Compressive testing demonstrated that the strength of the HGCCS is apparently enhanced because of the strong cross-linking of genipin and the resulting reinforcement of the HAp nanonetwork. The fluorescence properties of genipin-chitosan conjugation for convenient monitoring of the 3D porous scaffold biodegradability and cell localization in the scaffold was specifically explored using confocal laser scanning microscopy (CLSM). Furthermore, through scanning electron microscope (SEM) observation and immunofluorescence measurements of F-actin, we found that the HAp network-like nanostructure on the surface of the HGCCS can influence the morphology and integrin-mediated cytoskeleton organization of rat bone marrow-derived mesenchymal stem cells (BMSCs). Based on cell proliferation assays, rat BMSCs tend to have higher viability on HGCCS in vitro. The results of this study suggest that

  7. Biomimetic magnesium–carbonate-apatite nanocrystals endowed with strontium ions as anti-osteoporotic trigger

    Energy Technology Data Exchange (ETDEWEB)

    Iafisco, Michele, E-mail: michele.iafisco@istec.cnr.it; Ruffini, Andrea; Adamiano, Alessio; Sprio, Simone; Tampieri, Anna

    2014-02-01

    The present work investigates the preparation of biomimetic nanocrystalline apatites co-substituted with Mg, CO{sub 3} and Sr to be used as starting materials for the development of nanostructured bio-devices for regeneration of osteoporotic bone. Biological-like amounts of Mg and CO{sub 3} ions were inserted in the apatite structure to mimic the composition of bone apatite, whereas the addition of increasing quantities of Sr ions, from 0 up to 12 wt.%, as anti-osteoporotic agent, was evaluated. The chemical–physical features, the morphology, the degradation rates, the ion release kinetics as well as the in vitro bioactivity of the as-prepared apatites were fully evaluated. The results indicated that the incorporation of 12 wt.% of Sr can be viewed as a threshold for the structural stability of Mg–CO{sub 3}-apatite. Indeed, incorporation of lower quantity of Sr did not induce considerable variations in the chemical structure of Mg–CO{sub 3}-apatite, while when the Sr doping extent reached 12 wt.%, a dramatically destabilizing effect was detected on the crystal structure thus yielding alteration of the symmetry and distortion of the PO{sub 4}. As a consequence, this apatite exhibited the fastest degradation kinetic and the highest amount of Sr ions released when tested in physiological conditions. In this respect, the surface crystallization of new calcium phosphate phase when immersed in physiological-like solution occurred by different mechanisms and extents due to the different structural chemistry of the variously doped apatites. Nevertheless, all the apatites synthesized in this work exhibited in vitro bioactivity demonstrating their potential use to develop biomedical devices with anti-osteoporotic functionality. - Highlights: • Biomimetic nanocrystalline apatites co-substituted with Mg, CO{sub 3} and Sr were prepared. • Biological-like amounts of Mg and CO{sub 3} were inserted to mimic the composition of bone apatite. • The addition of increasing

  8. Biomimetic magnesium–carbonate-apatite nanocrystals endowed with strontium ions as anti-osteoporotic trigger

    International Nuclear Information System (INIS)

    Iafisco, Michele; Ruffini, Andrea; Adamiano, Alessio; Sprio, Simone; Tampieri, Anna

    2014-01-01

    The present work investigates the preparation of biomimetic nanocrystalline apatites co-substituted with Mg, CO 3 and Sr to be used as starting materials for the development of nanostructured bio-devices for regeneration of osteoporotic bone. Biological-like amounts of Mg and CO 3 ions were inserted in the apatite structure to mimic the composition of bone apatite, whereas the addition of increasing quantities of Sr ions, from 0 up to 12 wt.%, as anti-osteoporotic agent, was evaluated. The chemical–physical features, the morphology, the degradation rates, the ion release kinetics as well as the in vitro bioactivity of the as-prepared apatites were fully evaluated. The results indicated that the incorporation of 12 wt.% of Sr can be viewed as a threshold for the structural stability of Mg–CO 3 -apatite. Indeed, incorporation of lower quantity of Sr did not induce considerable variations in the chemical structure of Mg–CO 3 -apatite, while when the Sr doping extent reached 12 wt.%, a dramatically destabilizing effect was detected on the crystal structure thus yielding alteration of the symmetry and distortion of the PO 4 . As a consequence, this apatite exhibited the fastest degradation kinetic and the highest amount of Sr ions released when tested in physiological conditions. In this respect, the surface crystallization of new calcium phosphate phase when immersed in physiological-like solution occurred by different mechanisms and extents due to the different structural chemistry of the variously doped apatites. Nevertheless, all the apatites synthesized in this work exhibited in vitro bioactivity demonstrating their potential use to develop biomedical devices with anti-osteoporotic functionality. - Highlights: • Biomimetic nanocrystalline apatites co-substituted with Mg, CO 3 and Sr were prepared. • Biological-like amounts of Mg and CO 3 were inserted to mimic the composition of bone apatite. • The addition of increasing quantities of Sr (from 0 to 12

  9. Coating of Bio-mimetic Minerals-Substituted Hydroxyapatite on Surgical Grade Stainless Steel 316L by Electrophoretic Deposition for Hard tissue Applications

    Science.gov (United States)

    Govindaraj, Dharman; Rajan, Mariappan

    2018-02-01

    Third-era bio-implant materials intend to empower particular live cell reactions at the atomic level, these materials represented with a resorbable and biocompatibility that bodies recuperate once they have been embedded. Necessitate to decrease expenses in public health services has required the utilization of surgical grade stainless steel (SS 316L) as the most inexpensive choice for orthodontic and orthopaedic implants. 316L SS is one of the broadly used implant biomaterials in orthodontic and orthopaedic surgeries. Yet, frequently those discharge for toxic metal ions is confirm from the implants and hence a second surgery is required will remove those implant material. One approach to managing the discharge of toxic metal ions is to coat the implant substance with bio-mimetic minerals in hydroxyapatite (HA). Bio-mimetic minerals such as magnesium (Mg), strontium (Sr), also zinc (Zn) were revealed with animate bone growth furthermore restrain bone resorption both in vitro and in vivo. The present work deals with the electrophoretic deposition (EPD) for multi minerals substituted hydroxyapatite (M-HA) on the surface treated 316L SS under distinctive temperatures (27°C, (room temperature), 60 and 80°C). The resultant coatings were characterized by FT-IR, XRD, SEM-EDX, adhesion strength and leach out analysis.

  10. A graded graphene oxide-hydroxyapatite/silk fibroin biomimetic scaffold for bone tissue engineering.

    Science.gov (United States)

    Wang, Qian; Chu, Yanyan; He, Jianxin; Shao, Weili; Zhou, Yuman; Qi, Kun; Wang, Lidan; Cui, Shizhong

    2017-11-01

    To better mimic natural bone, a graphene oxide-hydroxyapatite/silk fibroin (cGO-HA/SF) scaffold was fabricated by biomineralizing carboxylated GO sheets, blending with SF, and freeze-drying. The material has increasing porosity and decreasing density from outside to inside. Analysis of GO mineralization in simulated body fluid indicated that carboxylation and Chitosan may synergistically regulate HA growth along the c-axis of weakly crystalline, rod-like GO-HA particles. Compared with HA/SF gradient composites, a cGO-HA gradient scaffold with cGO:HA mass ratio 1:4 has 5-fold and 2.5-fold higher compressive strength and compressive modulus, respectively. Additionally, the cGO-HA/SF composite stimulated mouse mesenchymal stem cell adhesion and proliferation, alkaline phosphatase secretion, and mineral deposition more strongly than HA/SF and pure HA scaffolds. Hence, the material may prove to be an excellent and versatile scaffold for bone tissue engineering. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Biomimetic synthesis of hydroxyapatite/bacterial cellulose nanocomposites for biomedical applications

    International Nuclear Information System (INIS)

    Wan, Y.Z.; Huang, Y.; Yuan, C.D.; Raman, S.; Zhu, Y.; Jiang, H.J.; He, F.; Gao, C.

    2007-01-01

    Hydroxyapatite (HAp) and bacterial cellulose (BC) are both excellent materials for use in biomaterial areas. The former has outstanding osteoconductivity and bioactivity and the latter is a high-strength nano-fibrous and extensively used biomaterial. In this work, the HAp/BC nanocomposites with a 3-dimensional (3-D) network were synthesized via a biological route by soaking both phosphorylated and unphosphorylated BCs in 1.5 simulated body fluid (SBF). Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) were employed to characterize the HAp/BC nanocomposites. SEM observations demonstrated that HAp crystals were uniformly formed on the phosphorylated BC fibers after soaking in 1.5 SBF whereas little HAp was observed on individual unphosphorylated BC fibers. Our experimental results suggested that the unphosphorylated BC did not induce HAp growth and that phosphorylation effectively triggered HAp formation on BC. Mechanisms were proposed for the explanation of the experimental observations. XRD and FTIR results revealed that the HAp crystals formed on the phosphorylated BC fibers were carbonate-containing with nano-sized crystallites and crystallinities less than 1%. These structural features were close to those of biological apatites

  12. Biomimetic synthesis of hydroxyapatite/bacterial cellulose nanocomposites for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Y.Z. [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China)]. E-mail: yzwantju@yahoo.com; Huang, Y. [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Yuan, C.D. [School of Chemical Engineering, Tianjin University, Tianjin 300072 (China); Raman, S. [Department of Community Health and Epidemiology, Queen' s University, Kingston, Ontario, Canada K7L 3N6 (Canada); Zhu, Y. [School of Chemical Engineering, Tianjin University, Tianjin 300072 (China); Jiang, H.J. [Wendeng Hospital of Orthopaedics, Shandong 264400 (China); He, F. [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Gao, C. [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China)

    2007-05-16

    Hydroxyapatite (HAp) and bacterial cellulose (BC) are both excellent materials for use in biomaterial areas. The former has outstanding osteoconductivity and bioactivity and the latter is a high-strength nano-fibrous and extensively used biomaterial. In this work, the HAp/BC nanocomposites with a 3-dimensional (3-D) network were synthesized via a biological route by soaking both phosphorylated and unphosphorylated BCs in 1.5 simulated body fluid (SBF). Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) were employed to characterize the HAp/BC nanocomposites. SEM observations demonstrated that HAp crystals were uniformly formed on the phosphorylated BC fibers after soaking in 1.5 SBF whereas little HAp was observed on individual unphosphorylated BC fibers. Our experimental results suggested that the unphosphorylated BC did not induce HAp growth and that phosphorylation effectively triggered HAp formation on BC. Mechanisms were proposed for the explanation of the experimental observations. XRD and FTIR results revealed that the HAp crystals formed on the phosphorylated BC fibers were carbonate-containing with nano-sized crystallites and crystallinities less than 1%. These structural features were close to those of biological apatites.

  13. Preparation and Characterization of Biomimetic Hydroxyapatite-Resorbable Polymer Composites for Hard Tissue Repair

    Science.gov (United States)

    Hiebner, Kristopher Robert

    Autografts are the orthopedic "gold standard" for repairing bone voids. Autografts are osteoconductive and do not elicit an immune response, but they are in short supply and require a second surgery to harvest the bone graft. Allografts are currently the most common materials used for the repair of segmental defects in hard tissue. Unlike autografts, allografts can cause an undesirable immune response and the possibility of disease transmission is a major concern. As an alternative to the above approaches, recent research efforts have focused on the use of composite materials made from hydroxyapatite (HA) and bioresorbable polymers, such as poly-L-lactide (PLLA). Recent results have shown that the surface hydroxides on HA can initiate the ring opening polymerization (ROP) of L-lactide and other lactones creating a composite with superior interfacial strength. This thesis demonstrates that the surface of porous biologically derived HA substrates, such as coralline HA and trabecular bone, can be used to initiate the ROP of L-lactide and other lactones from the vapor phase. This process increases the strength of the porous scaffold through the deposition of a thin, uniform polymer coating, while maintaining the porous structure. The kinetics of the chemical vapor deposition polymerization (CVDP) are described using a quartz crystal microbalance (QCM). The reaction temperature and monomer vapor pressure are found to affect the rate of the polymerization. Also described in this thesis is the preparation of a porous polymer scaffold that mimics the structure of demineralized bone matrix (DBM). This demineralized bone matrix simulant (DBMS) is created using anorganic bovine bone as a template to initiate the polymerization of various lactones, followed by the removal of the HA scaffold. This material retained its shape and exhibits mechanical properties superior to DBM. Finally it is shown that HA can be used to initiate the ROP of a-caprolactam and the biocompatibility

  14. Controllable synthesis of hydroxyapatite nanocrystals via a dendrimer-assisted hydrothermal process

    International Nuclear Information System (INIS)

    Zhou Zhuohua; Zhou, Ping-Le; Yang Shiping; Yu Xibin; Yang Liangzhun

    2007-01-01

    The morphology and size of hydroxyapatite Ca 10 (PO 4 ) 6 (OH) 2 (denoted HAP) can be controlled under hydrothermal treatment assisted with different dendrimers, such as carboxylic terminated poly(amidoamine) (PAMAM) and polyhydroxy terminated PAMAM. The structure and morphology were characterized by X-ray diffraction (XRD), infrared spectroscopy (IR) and transmission electron microscopy (TEM). IR spectra were also used to investigate the complexation of Ca 2+ with PAMAM. The results revealed that the inner cores of the PAMAM dendrimers are hydrophilic and potentially open to calcium ions, since interior nitrogen moieties serve as complexation sites, especially in case of the polyhydroxy terminated PAMAM. And the reasonable mechanism of crystallization was proposed that it can be attributed to the localization of nucleation site: external or interior PAMAM. Additionally, the PAMAM dendrimer with carboxylic and polyhydroxy groups has an effective influence on the size and shape of hydroxyapatite (HAP) nanostructures. Different crystal morphology was accomplished by adsorption of different dendrimers onto specific faces of growing crystals, altering the relative growth rates of the different crystallographic faces and leading to different crystal habits

  15. Experimental evidence and structural modeling of nonstoichiometric (010) surfaces coexisting in hydroxyapatite nano-crystals.

    Science.gov (United States)

    Ospina, C A; Terra, J; Ramirez, A J; Farina, M; Ellis, D E; Rossi, A M

    2012-01-01

    High-resolution transmission electron microscopy (HRTEM) and ab initio quantum-mechanical calculations of electronic structure were combined to investigate the structure of the hydroxyapatite (HA) (010) surface, which plays an important role in HA interactions with biological media. HA was synthesized by in vitro precipitation at 37°C. HRTEM images revealed thin elongated rod nanoparticles with preferential growth along the [001] direction and terminations parallel to the (010) plane. The focal series reconstruction (FSR) technique was applied to develop an atomic-scale structural model of the high-resolution images. The HRTEM simulations identified the coexistence of two structurally distinct terminations for (010) surfaces: a rather flat Ca(II)-terminated surface and a zig-zag structure with open OH channels. Density functional theory (DFT) was applied in a periodic slab plane-wave pseudopotential approach to refine details of atomic coordination and bond lengths of Ca(I) and Ca(II) sites in hydrated HA (010) surfaces, starting from the HRTEM model. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Effect of plasma surface functionalization on preosteoblast cells spreading and adhesion on a biomimetic hydroxyapatite layer formed on a titanium surface

    International Nuclear Information System (INIS)

    Myung, Sung Woon; Ko, Yeong Mu; Kim, Byung Hoon

    2013-01-01

    This study examined the plasma surface modification of biomimetic hydroxyapatite (HAp) formed on a titanium (Ti) surface as well as its influence on the behavior of preosteoblast cells. Ti substrates pre-treated with a plasma-polymerized thin film rich in carboxyl groups were subjected to a biomimetic process in a simulated body fluid solution to synthesize the HAp. The HAp layer grown on Ti substrate was then coated with two types of plasma polymerized acrylic acid and allyl amine thin film. The different types of Ti substrates were characterized by attenuated total reflection Fourier transform infrared spectroscopy, energy dispersive spectroscopy and X-ray diffraction. HAp with a Ca/P ratio from 1.25 to 1.38 was obtained on the Ti substrate and hydrophilic carboxyl (-COOH) and amine (-NH 2 ) functional groups were introduced to its surface. Scanning electron microscopy was used to observe the surface of the HAp coatings and the morphology of MC3T3-E1 cells. These results showed that the -COOH-modified HAp surfaces promoted the cell spreading synergistically by changing the surface morphology and chemical state.-NH 2 modified HAp had the lowest cell spreading and proliferation compared to HAp and -COOH-modified HAp. These results correspond to fluorescein analysis, which showed many more cell spreading of COOH/HAp/Ti surface compared to HAp and NH 2 modified HAp. A MTT assay was used to evaluate cell proliferation. The results showed that the proliferation of MC3T3-E1 cells increased in the order of COOH/HAp/Ti > HAp/Ti > NH 2 /Ti > Ti, corresponding to the effect of cell spreading for 6 days. The change in morphology and the chemical surface properties of the biomaterial via plasma polymerization can affect the behavior of MC3T3-E1 cells.

  17. Effect of plasma surface functionalization on preosteoblast cells spreading and adhesion on a biomimetic hydroxyapatite layer formed on a titanium surface

    Energy Technology Data Exchange (ETDEWEB)

    Myung, Sung Woon; Ko, Yeong Mu; Kim, Byung Hoon, E-mail: kim5055@chosun.ac.kr

    2013-12-15

    This study examined the plasma surface modification of biomimetic hydroxyapatite (HAp) formed on a titanium (Ti) surface as well as its influence on the behavior of preosteoblast cells. Ti substrates pre-treated with a plasma-polymerized thin film rich in carboxyl groups were subjected to a biomimetic process in a simulated body fluid solution to synthesize the HAp. The HAp layer grown on Ti substrate was then coated with two types of plasma polymerized acrylic acid and allyl amine thin film. The different types of Ti substrates were characterized by attenuated total reflection Fourier transform infrared spectroscopy, energy dispersive spectroscopy and X-ray diffraction. HAp with a Ca/P ratio from 1.25 to 1.38 was obtained on the Ti substrate and hydrophilic carboxyl (-COOH) and amine (-NH{sub 2}) functional groups were introduced to its surface. Scanning electron microscopy was used to observe the surface of the HAp coatings and the morphology of MC3T3-E1 cells. These results showed that the -COOH-modified HAp surfaces promoted the cell spreading synergistically by changing the surface morphology and chemical state.-NH{sub 2} modified HAp had the lowest cell spreading and proliferation compared to HAp and -COOH-modified HAp. These results correspond to fluorescein analysis, which showed many more cell spreading of COOH/HAp/Ti surface compared to HAp and NH{sub 2} modified HAp. A MTT assay was used to evaluate cell proliferation. The results showed that the proliferation of MC3T3-E1 cells increased in the order of COOH/HAp/Ti > HAp/Ti > NH{sub 2}/Ti > Ti, corresponding to the effect of cell spreading for 6 days. The change in morphology and the chemical surface properties of the biomaterial via plasma polymerization can affect the behavior of MC3T3-E1 cells.

  18. Improving osteointegration and osteogenesis of three-dimensional porous Ti6Al4V scaffolds by polydopamine-assisted biomimetic hydroxyapatite coating.

    Science.gov (United States)

    Li, Yong; Yang, Wei; Li, Xiaokang; Zhang, Xing; Wang, Cairu; Meng, Xiangfei; Pei, Yifeng; Fan, Xiangli; Lan, Pingheng; Wang, Chunhui; Li, Xiaojie; Guo, Zheng

    2015-03-18

    Titanium alloys with various porous structures can be fabricated by advanced additive manufacturing techniques, which are attractive for use as scaffolds for bone defect repair. However, modification of the scaffold surfaces, particularly inner surfaces, is critical to improve the osteointegration of these scaffolds. In this study, a biomimetic approach was employed to construct polydopamine-assisted hydroxyapatite coating (HA/pDA) onto porous Ti6Al4V scaffolds fabricated by the electron beam melting method. The surface modification was characterized with the field emission scanning electron microscopy, energy dispersive spectroscopy, water contact angle measurement, and confocal laser scanning microscopy. Attachment and proliferation of MC3T3-E1 cells on the scaffold surface were significantly enhanced by the HA/pDA coating compared to the unmodified surfaces. Additionally, MC3T3-E1 cells grown on the HA/pDA-coated Ti6Al4V scaffolds displayed significantly higher expression of runt-related transcription factor-2, alkaline phosphatase, osteocalcin, osteopontin, and collagen type-1 compared with bare Ti6Al4V scaffolds after culture for 14 days. Moreover, microcomputed tomography analysis and Van-Gieson staining of histological sections showed that HA/pDA coating on surfaces of porous Ti6Al4V scaffolds enhanced osteointegration and significantly promoted bone regeneration after implantation in rabbit femoral condylar defects for 4 and 12 weeks. Therefore, this study provides an alternative to biofunctionalized porous Ti6Al4V scaffolds with improved osteointegration and osteogenesis functions for orthopedic applications.

  19. Poly(allyl methacrylate) functionalized hydroxyapatite nanocrystals via the combination of surface-initiated RAFT polymerization and thiol-ene protocol: a potential anticancer drug nanocarrier.

    Science.gov (United States)

    Bach, Long Giang; Islam, Md Rafiqul; Vo, Thanh-Sang; Kim, Se-Kwon; Lim, Kwon Taek

    2013-03-15

    Hydroxyapatite nanocrystals (HAP NCs) were encapsulated by poly(allyl methacrylate) (PolyAMA) employing controlled surface-initiated reversible addition-fragmentation chain transfer (SI-RAFT) polymerization of allyl methacrylate to afford HAP-PolyAMA nanohybrids. The subsequent thiol-ene coupling of nanohybrids with 2-mercaptosuccinic acid resulted HAP-Poly(AMA-COOH) possessing multicarboxyl group. The formation of the nanohybrids was confirmed by FT-IR and EDS analyses. The TGA and FE-SEM investigation were further suggested the grafting of PolyAMA onto HAP NCs. The utility of the HAP-PolyAMA nanohybrid as drug carrier was also explored. The pendant carboxyl groups on the external layers of nanohybrids were conjugated with anticancer drug cisplatin to afford HAP-Poly(AMA-COOH)/Pt complex. The formation of the complex was confirmed by FT-IR, XPS, and FE-SEM. In vitro evaluation of the synthesized complex as nanomedicine revealed its potential chemotherapeutic efficacy against cancer cell lines. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Role of magnesium on the biomimetic deposition of calcium phosphate

    Science.gov (United States)

    Sarma, Bimal K.; Sarma, Bikash

    2016-10-01

    Biomimetic depositions of calcium phosphate (CaP) are carried out using simulated body fluid (SBF), calcifying solution and newly developed magnesium containing calcifying solution. Calcium phosphate has a rich phase diagram and is well known for its excellent biocompatibility and bioactivity. The most common phase is hydroxyapatite (HAp), an integral component of human bone and tooth, widely used in orthopedic and dental applications. In addition, calcium phosphate nanoparticles show promise for the targeted drug delivery. The doping of calcium phosphate by magnesium, zinc, strontium etc. can change the protein uptake by CaP nanocrystals. This work describes the role of magnesium on the nucleation and growth of CaP on Ti and its oxide substrates. X-ray diffraction studies confirm formation of HAp nanocrystals which closely resemble the structure of bone apatite when grown using SBF and calcifying solution. It has been observed that magnesium plays crucial role in the nucleation and growth of calcium phosphate. A low magnesium level enhances the crystallinity of HAp while higher magnesium content leads to the formation of amorphous calcium phosphate (ACP) phase. Interestingly, the deposition of ACP phase is rapid when magnesium ion concentration in the solution is 40% of calcium plus magnesium ions concentration. Moreover, high magnesium content alters the morphology of CaP films.

  1. A double-blind randomized-controlled trial comparing the desensitizing efficacy of a new dentifrice containing carbonate/hydroxyapatite nanocrystals and a sodium fluoride/potassium nitrate dentifrice.

    Science.gov (United States)

    Orsini, Giovanna; Procaccini, Maurizio; Manzoli, Lamberto; Giuliodori, Francesca; Lorenzini, Alessandro; Putignano, Angelo

    2010-06-01

    Several dentifrices have shown to be effective in reducing dentine hypersensitivity (DH), but more effective products are needed. The aim of the study was to evaluate the desensitizing efficacy of a new dentifrice based on zinc-carbonate hydroxyapatite (CHA) nanocrystals. Using a double-blind, randomized design, the new dentifrice was compared with potassium nitrate/fluoride dentifrice (active control). The participant's DH was evaluated at baseline and after 4 and 8 weeks using airblast (primary outcome), tactile, cold water and subjective tests (secondary outcomes). The final sample consisted of 70 subjects with baseline DH; 36 received the new dentifrice and 34 the control one. Both dentifrices were largely effective; the percentage of score reduction from baseline to 8 weeks was greater than 28% for all tests (and greater than 55% for the cold water test) in both groups. As compared with controls, experimental subjects had a significantly greater improvement in the airblast test score (mean percentage of reduction of 46.0%versus 29.4% in controls) and the subjective test score (47.5%versus 28.1%, respectively), with both differences already being significant after 4 weeks. In contrast, there was no significant difference between groups for either the tactile or cold water tests at any time point and with any outcome. This study documented that the new dentifrice containing zinc-CHA nanocrystals significantly reduced dentinal hypersensitivity after 4 and 8 weeks, supporting its utility in clinical practice.

  2. Crystallization of modified hydroxyapatite on titanium implants

    International Nuclear Information System (INIS)

    Golovanova, O A; Izmailov, R R; Zaits, A V; Ghyngazov, S A

    2016-01-01

    Carbonated-hydroxyapatite (CHA) and Si-hydroxyapatite (Si-HA) precipitation have been synthesized from the model bioliquid solutions (synovial fluid and SBF). It is found that all the samples synthesized from the model solutions are single-phase and represent hydroxyapatite. The crystallization of the modified hydroxyapatite on alloys of different composition, roughness and subjected to different treatment techniques was investigated. Irradiation of the titanium substrates with the deposited biomimetic coating can facilitate further growth of the crystal and regeneration of the surface. (paper)

  3. Healing of Osteochondral Defects Implanted with Biomimetic Scaffolds of Poly(ε-Caprolactone)/Hydroxyapatite and Glycidyl-Methacrylate-Modified Hyaluronic Acid in a Minipig.

    Science.gov (United States)

    Hsieh, Yi-Ho; Shen, Bo-Yuan; Wang, Yao-Horng; Lin, Bojain; Lee, Hung-Maan; Hsieh, Ming-Fa

    2018-04-09

    Articular cartilage is a structure lack of vascular distribution. Once the cartilage is injured or diseased, it is unable to regenerate by itself. Surgical treatments do not effectively heal defects in articular cartilage. Tissue engineering is the most potential solution to this problem. In this study, methoxy poly(ethylene glycol)-block-poly(ε-caprolactone) (mPEG-PCL) and hydroxyapatite at a weight ratio of 2:1 were mixed via fused deposition modeling (FDM) layer by layer to form a solid scaffold. The scaffolds were further infiltrated with glycidyl methacrylate hyaluronic acid loading with 10 ng/mL of Transforming Growth Factor-β1 and photo cross-linked on top of the scaffolds. An in vivo test was performed on the knees of Lanyu miniature pigs for a period of 12 months. The healing process of the osteochondral defects was followed by computer tomography (CT). The defect was fully covered with regenerated tissues in the control pig, while different tissues were grown in the defect of knee of the experimental pig. In the gross anatomy of the cross section, the scaffold remained in the subchondral location, while surface cartilage was regenerated. The cross section of the knees of both the control and experimental pigs were subjected to hematoxylin and eosin staining. The cartilage of the knee in the experimental pig was partially matured, e.g., few chondrocyte cells were enclosed in the lacunae. In the knee of the control pig, the defect was fully grown with fibrocartilage. In another in vivo experiment in a rabbit and a pig, the composite of the TGF-β1-loaded hydrogel and scaffolds was found to regenerate hyaline cartilage. However, scaffolds that remain in the subchondral lesion potentially delay the healing process. Therefore, the structural design of the scaffold should be reconsidered to match the regeneration process of both cartilage and subchondral bone.

  4. Healing of Osteochondral Defects Implanted with Biomimetic Scaffolds of Poly(ε-Caprolactone/Hydroxyapatite and Glycidyl-Methacrylate-Modified Hyaluronic Acid in a Minipig

    Directory of Open Access Journals (Sweden)

    Yi-Ho Hsieh

    2018-04-01

    Full Text Available Articular cartilage is a structure lack of vascular distribution. Once the cartilage is injured or diseased, it is unable to regenerate by itself. Surgical treatments do not effectively heal defects in articular cartilage. Tissue engineering is the most potential solution to this problem. In this study, methoxy poly(ethylene glycol-block-poly(ε-caprolactone (mPEG-PCL and hydroxyapatite at a weight ratio of 2:1 were mixed via fused deposition modeling (FDM layer by layer to form a solid scaffold. The scaffolds were further infiltrated with glycidyl methacrylate hyaluronic acid loading with 10 ng/mL of Transforming Growth Factor-β1 and photo cross-linked on top of the scaffolds. An in vivo test was performed on the knees of Lanyu miniature pigs for a period of 12 months. The healing process of the osteochondral defects was followed by computer tomography (CT. The defect was fully covered with regenerated tissues in the control pig, while different tissues were grown in the defect of knee of the experimental pig. In the gross anatomy of the cross section, the scaffold remained in the subchondral location, while surface cartilage was regenerated. The cross section of the knees of both the control and experimental pigs were subjected to hematoxylin and eosin staining. The cartilage of the knee in the experimental pig was partially matured, e.g., few chondrocyte cells were enclosed in the lacunae. In the knee of the control pig, the defect was fully grown with fibrocartilage. In another in vivo experiment in a rabbit and a pig, the composite of the TGF-β1-loaded hydrogel and scaffolds was found to regenerate hyaline cartilage. However, scaffolds that remain in the subchondral lesion potentially delay the healing process. Therefore, the structural design of the scaffold should be reconsidered to match the regeneration process of both cartilage and subchondral bone.

  5. Biomimetic dentistry

    Directory of Open Access Journals (Sweden)

    Suchetana Goswami

    2018-01-01

    Full Text Available “Biomimetics” is the field of science that uses the natural system of synthesizing materials through biomimicry. This method can be widely used in dentistry for regeneration of dental structures and replacement of lost dental tissues. This is a review paper that states its scope, history, different fields of biomimetic dentistry, and its future conditions in India.

  6. Biomimetic dentistry

    OpenAIRE

    Suchetana Goswami

    2018-01-01

    “Biomimetics” is the field of science that uses the natural system of synthesizing materials through biomimicry. This method can be widely used in dentistry for regeneration of dental structures and replacement of lost dental tissues. This is a review paper that states its scope, history, different fields of biomimetic dentistry, and its future conditions in India.

  7. Incorporation of different antibiotics into carbonated hydroxyapatite coatings on titanium implants, release and antibiotic efficacy

    NARCIS (Netherlands)

    Stigter, M.; Bezemer, J.M.; de Groot, K.; Layrolle, P.

    2004-01-01

    Carbonated hydroxyapatite (CHA) coatings were applied onto titanium implants by using a biomimetic precipitation method. Different antibiotics were incorporated into the CHA coatings and their release and efficacy against bacteria growth were studied in vitro. The following antibiotics were used

  8. Biomimetic modelling.

    OpenAIRE

    Vincent, Julian F V

    2003-01-01

    Biomimetics is seen as a path from biology to engineering. The only path from engineering to biology in current use is the application of engineering concepts and models to biological systems. However, there is another pathway: the verification of biological mechanisms by manufacture, leading to an iterative process between biology and engineering in which the new understanding that the engineering implementation of a biological system can bring is fed back into biology, allowing a more compl...

  9. A comparative study of hydroxyapatite nanoparticles synthesized by different routes

    OpenAIRE

    Paz, Adrian; Guadarrama, Dainelys; López, Mónica; E. González, Jesús; Brizuela, Nayrim; Aragón, Javier

    2012-01-01

    In this study, bioactive hydroxyapatite nanoparticles were prepared by two different methods: wet chemical precipitation and biomimetic precipitation. The aim was to evaluate the morphology, particle-size, crystallinity and phases of the powders obtained by traditional wet chemical precipitation and the novel biomimetic precipitation using a supersaturated calcium solution. The nanoparticles were investigated by transmission electron microscopy, Fourier transform infrared spectroscopy and X-r...

  10. Ferroelectric Polarization in Nanocrystalline Hydroxyapatite Thin Films on Silicon

    Science.gov (United States)

    Lang, S. B.; Tofail, S. A. M.; Kholkin, A. L.; Wojtaś, M.; Gregor, M.; Gandhi, A. A.; Wang, Y.; Bauer, S.; Krause, M.; Plecenik, A.

    2013-01-01

    Hydroxyapatite nanocrystals in natural form are a major component of bone- a known piezoelectric material. Synthetic hydroxyapatite is widely used in bone grafts and prosthetic pyroelectric coatings as it binds strongly with natural bone. Nanocrystalline synthetic hydroxyapatite films have recently been found to exhibit strong piezoelectricity and pyroelectricity. While a spontaneous polarization in hydroxyapatite has been predicted since 2005, the reversibility of this polarization (i.e. ferroelectricity) requires experimental evidence. Here we use piezoresponse force microscopy to demonstrate that nanocrystalline hydroxyapatite indeed exhibits ferroelectricity: a reversal of polarization under an electrical field. This finding will strengthen investigations on the role of electrical polarization in biomineralization and bone-density related diseases. As hydroxyapatite is one of the most common biocompatible materials, our findings will also stimulate systematic exploration of lead and rare-metal free ferroelectric devices for potential applications in areas as diverse as in vivo and ex vivo energy harvesting, biosensing and electronics. PMID:23884324

  11. Hydroxyapatite Reinforced Coatings with Incorporated Detonationally Generated Nanodiamonds

    International Nuclear Information System (INIS)

    Pramatarova, L.; Pecheva, E.; Hikov, T.; Fingarova, D.; Dimitrova, R.; Spassov, T.; Krasteva, N.; Mitev, D.

    2010-01-01

    We studied the effect of the substrate chemistry on the morphology of hydroxyapatite-detonational nanodiamond composite coatings grown by a biomimetic approach (immersion in a supersaturated simulated body fluid). When detonational nanodiamond particles were added to the solution, the morphology of the grown for 2 h composite particles was porous but more compact then that of pure hydroxyapatite particles. The nanodiamond particles stimulated the hydroxyapatite growth with different morphology on the various substrates (Ti, Ti alloys, glasses, Si, opal). Biocompatibility assay with MG63 osteoblast cells revealed that the detonational nanodiamond water suspension with low and average concentration of the detonational nanodiamond powder is not toxic to living cells.

  12. Solid state NMR method development and studies of biological and biomimetic nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Yanyan [Iowa State Univ., Ames, IA (United States)

    2011-01-01

    This thesis describes application and development of advanced solid-state nuclear magnetic resonance techniques for complex materials, in particular organic-inorganic nanocomposites and thermoelectric tellurides. The apatite-collagen interface, essential for understanding the biomineralization process in bone and engineering the interface for controlled bio-mimetic synthesis and optimized mechanical properties, is buried within the nanocomposite of bone. We used multinuclear solid-state NMR to study the composition and structure of the interface. Citrate has been identified as the main organic molecule strongly bound to the apatite surface with a density of 1/(2 nm)2, covering 1/6 of the total surface area in bovine bone. Citrate provides more carboxylate groups, one of the key functional groups found to affect apatite nucleation and growth, than all the non-collagenous proteins all together in bone; thus we propose that citrate stabilizes apatite crystals at a very small thickness of ~3 nm (4 unit cells) to increase bone fracture tolerance. The hypothesis has been confirmed in vitro by adding citrate in the bio-mimetic synthesis of polymerhydroxyapatite nanocomposites. The results have shown that the size of hydroxyapatite nanocrystals decreases as increasing citrate concentration. With citrate concentrations comparable to that in body fluids, similar-sized nanocrystals as in bone have been produced. Besides the dimensions of the apatite crystals, the composition of bone also affects its biofunctional and macroscopic mechanical properties; therefore, our team also extended its effort to enhance the inorganic portion in our bio-mimetic synthesis from originally 15 wt% to current 50 wt% compared to 65 wt% in bovine bone, by using Lysine-Leucine hydroxyapatite nucleating diblock co-polypeptide, which forms a gel at very low concentration. In this thesis, various advanced solid state NMR techniques have been employed to characterize nanocomposites

  13. Size effect in X-ray and electron diffraction patterns from hydroxyapatite particles

    International Nuclear Information System (INIS)

    Suvorova, E.I.; Buffat, P.-A.

    2001-01-01

    High-resolution transmission electron microscopy (HRTEM), electron microdiffraction, and X-ray diffraction were used to study hydroxyapatite specimens with particle sizes from a few nanometers to several hundreds of nanometers. Diffuse scattering (without clear reflections in transmission diffraction patterns) or strongly broadened peaks in X-ray diffraction patterns are characteristic for agglomerated hydroxyapatite nanocrystals. However, HRTEM and microdiffraction showed that this cannot be considered as an indication of the amorphous state of the matter but rather as the demonstration of size effect and the morphological and structural features of hydroxyapatite nanocrystals

  14. A biomimetic approach toward artificial bone-like materials

    OpenAIRE

    Bertozzi, Carolyn R.

    2001-01-01

    Bone consists of microcrystalline hydroxyapatite and collagen, an elastic protein matrix that is decorated with mineral-nucleating phosphoproteins. Our rational design of artificial bone-like material uses natural bone as a guide. Hydrogel and self-assembling polymers that possess anionic groups suitably positioned for nucleating biominerals, and therefore mimic the natural function of the collagen-phosphoprotein matrix in bone, were designed to direct template-driven biomimetic mineralizatio...

  15. An efficient biomimetic coating methodology for a prosthetic alloy

    International Nuclear Information System (INIS)

    Adawy, Alaa; Abdel-Fattah, Wafa I.

    2013-01-01

    The combination of the load-bearing metallic implants with the bioactive materials in the design of synthetic implants is an important aspect in the biomaterials research. Biomimetic coating of bioinert alloys with calcium phosphate phases provides a good alternative to the prerequisite for the continual replacement of implants because of the failure of bone-implant integration. We attempted to accelerate the biomimetic coating process of stainless steel alloy (316L) with biomimetic apatite. In addition, we investigated the incorporation of functioning minerals such as strontianite and smithsonite into the deposited layer. In order to develop a highly mature apatite coating, our method requires soaking of the pre-treated alloy in highly concentrated synthetic body fluid for only few hours. Surface characterizations were performed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). Also, the deposited apatitic layers were analysed by powder diffraction X-ray analysis (XRD). 316L surface showed the growth of highly crystalline, low carbonated hydroxyapatite, after only 6 h of the whole soaking process. Highlights: ► The manuscript describes a fast and efficient biomimetic coating methodology. ► This methodology can be used for metallic implants. ► 316L was coated with crystalline hydroxyapatite. ► Addition of strontium and zinc lead to the deposition of brushite. ► Coating of all synthetic solutions is highly crystalline

  16. Biomimetic Flow Sensors

    NARCIS (Netherlands)

    Casas, J.; Liu, Chang; Krijnen, Gijsbertus J.M.

    2012-01-01

    Biomimetic flow sensors are biologically inspired devices that measure the speed and direction of fluids. This survey starts by describing the role and functioning of airflow-sensing hairs in arthropods and in fishes, carries on with the biomimetic MEMS implementations, both for air and water flow

  17. Aqueous synthesis and characterization of bovine hemoglobin-conjugated cadmium sulfide nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Guangrui [Institute of Environmental and Municipal Engineering, North China University of Water Conservancy and Electric Power, Zhengzhou 450011 (China); Qin, Dezhi, E-mail: dezhiqin@163.com [College of Chemistry and Chemical Engineering, Pingdingshan University, Pingdingshan 467000 (China); Du, Xian; Zhang, Li; Zhao, Ganqing; Zhang, Qiuxia; Wu, Jiulin [College of Chemistry and Chemical Engineering, Pingdingshan University, Pingdingshan 467000 (China)

    2014-08-01

    Highlights: • CdS nanocrystals were synthesized by biomimetic method in bovine hemoglobin (BHb) solution. • The study of the interaction between Cd{sup 2+}/CdS and BHb. • The optical properties of BHb-conjugated CdS nanocrystals. • The synthesis process of BHb-conjugated CdS nanocrystals is facile, effective and environment friendly. • The change of secondary structure of BHb after binding to CdS nanocrystals. - Abstract: Cadmium sulfide (CdS) nanocrystals with average diameter about 5.5 nm were synthesized in aqueous solution of bovine hemoglobin (BHb) via simple biomimetic method. Powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and selected area electron diffraction (SAED) characterizations were used to determine the structure and morphology of CdS nanocrystals. It was revealed that amount of BHb, chelating of Cd{sup 2+} to BHb and reaction temperature were key factors in controlling shape and dispersion of CdS nanocrystals. The binding sites of BHb to CdS nanocrystals and the change of secondary structure of protein have been identified by Fourier transform infrared (FT-IR) and circular dichroism (CD) spectroscopy. It was found that conjugating of BHb with Cd{sup 2+} and CdS could protect nanocrystals from agglomerating. Moreover, the thermostability of BHb enhanced after conjugating with CdS nanocrystals. The interaction mechanism of BHb with Cd{sup 2+}/CdS was also proposed. The quantum-confined effect of CdS nanocrystals was confirmed by ultraviolet–visible (UV–vis) spectrum. The nanocrystals exhibited a well-defined photoluminescence (PL) emission feature at about 510 nm with narrow full width at half maximum (FWHM)

  18. [Biomimetic mineralization of rod-like cellulose nano-whiskers and spectrum analysis].

    Science.gov (United States)

    Qu, Ping; Wang, Xuan; Cui, Xiao-xia; Zhang, Li-ping

    2012-05-01

    Cellulose nano-whiskers/nano-hydroxyapatite composite was prepared with biomimetic mineralization using rod-like cellulose nano-whiskers as template. The cellulose nano-whiskers and cellulose nano-whiskers/nano-hydroxyapatite composite were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope-energy dispersive analysis of X-rays (SEM-EDXA). Variation and distribution of carbon, oxygen, calcium, and phosphorus in the composites were studied. The morphologies and growth mechanism of nano-hydroxyapatite were analyzed. The results showed that nano-hydroxyapatite was formed on the surface of cellulose nano-whiskers; the carbon-oxygen ratio of cellulose nano-whiskers and cellulose nano-whiskers/nano-hydroxyapatite composite was 1.81 and 1.54, respectively; the calcium-phosphorus ratio of the composite was 1.70. The nucleation of nano-hydroxyapatite was around the hydroxyl groups of cellulose nano-whiskers. It is suggested that there is coordination between the hydroxyl groups of cellulose nano-whiskers and calcium ions of nano-hydroxyapatite. The nano-hydroxyapatite can distribute in the matrix of cellulose nano-whiskers. From the atomic force microscope (AFM) images, we can see that the diameter of the spherical nano-hydroxyapatite particles was about 20 nm.

  19. Waste utilization for the controlled synthesis of nanosized hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Nayar, Suprabha, E-mail: Suprabha.nayar@gmail.com [National Metallurgical Laboratory, Jamshedpur (India); Guha, Avijit [National Metallurgical Laboratory, Jamshedpur (India)

    2009-05-05

    This work uses biomolecules in waste and medicinally important materials for the synthesis of hydroxyapatite nanoparticles. Orange and potato peel, eggshell, papaya leaf and calendula flower extracts have varied biomolecules, which exert a significant, control on the in situ synthesis of nanosized hydroxyapatite particles. The biomimetic synthesis of inorganic particles using known matrices is already well established, however, there are only a few reports using compound extracts. The synthesized nanocomposite has been characterized using X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy studies. Role of varied biomolecules in controlled inorganic synthesis may have tremendous technological impact.

  20. Hydroxyapatite-silver nanoparticles coatings on porous polyurethane scaffold.

    Science.gov (United States)

    Ciobanu, Gabriela; Ilisei, Simona; Luca, Constantin

    2014-02-01

    The present paper is focused on a study regarding the possibility of obtaining hydroxyapatite-silver nanoparticle coatings on porous polyurethane scaffold. The method applied is based on a combined strategy involving hydroxyapatite biomimetic deposition on polyurethane surface using a Supersaturated Calcification Solution (SCS), combined with silver ions reduction and in-situ crystallization processes on hydroxyapatite-polyurethane surface by sample immersing in AgNO3 solution. The morphology, composition and phase structure of the prepared samples were characterized by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS) measurements. The data obtained show that a layer of hydroxyapatite was deposited on porous polyurethane support and the silver nanoparticles (average size 34.71 nm) were dispersed among and even on the hydroxyapatite crystals. Hydroxyapatite/polyurethane surface acts as a reducer and a stabilizing agent for silver ions. The surface plasmon resonance peak in UV-Vis absorption spectra showed an absorption maximum at 415 nm, indicating formation of silver nanoparticles. The hydroxyapatite-silver polyurethane scaffolds were tested against Staphylococcus aureus and Escherichia coli and the obtained data were indicative of good antibacterial properties of the materials. © 2013.

  1. Biomimetic thin film synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Graff, G.L.; Campbell, A.A.; Gordon, N.R.

    1995-05-01

    The purpose of this program is to develop a new process for forming thin film coatings and to demonstrate that the biomimetic thin film technology developed at PNL is useful for industrial applications. In the biomimetic process, mineral deposition from aqueous solution is controlled by organic functional groups attached to the underlying substrate surface. The coatings process is simple, benign, inexpensive, energy efficient, and particularly suited for temperature sensitive substrate materials (such as polymers). In addition, biomimetic thin films can be deposited uniformly on complex shaped and porous substrates providing a unique capability over more traditional line-of-sight methods.

  2. Hydroxyapatite-silver nanoparticles coatings on porous polyurethane scaffold

    International Nuclear Information System (INIS)

    Ciobanu, Gabriela; Ilisei, Simona; Luca, Constantin

    2014-01-01

    The present paper is focused on a study regarding the possibility of obtaining hydroxyapatite-silver nanoparticle coatings on porous polyurethane scaffold. The method applied is based on a combined strategy involving hydroxyapatite biomimetic deposition on polyurethane surface using a Supersaturated Calcification Solution (SCS), combined with silver ions reduction and in-situ crystallization processes on hydroxyapatite-polyurethane surface by sample immersing in AgNO 3 solution. The morphology, composition and phase structure of the prepared samples were characterized by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS) measurements. The data obtained show that a layer of hydroxyapatite was deposited on porous polyurethane support and the silver nanoparticles (average size 34.71 nm) were dispersed among and even on the hydroxyapatite crystals. Hydroxyapatite/polyurethane surface acts as a reducer and a stabilizing agent for silver ions. The surface plasmon resonance peak in UV-Vis absorption spectra showed an absorption maximum at 415 nm, indicating formation of silver nanoparticles. The hydroxyapatite-silver polyurethane scaffolds were tested against Staphylococcus aureus and Escherichia coli and the obtained data were indicative of good antibacterial properties of the materials. - Highlights: • The hydroxyapatite and silver nanoparticles were grown on the polyurethane scaffold • The hydroxyapatite/polyurethane acts as reducing agent, stabilizer and matrix for Ag • The samples were well characterized by SEM-EDX, XRD, XPS, UV-visible spectroscopy • The hydroxyapatite/silver polyurethane scaffold shows antibacterial property

  3. Biomimetic growth and substrate dependent mechanical properties of bone like apatite nucleated on Ti and magnetron sputtered TiO2 nanostructure

    Science.gov (United States)

    Sarma, Bimal K.; Das, Apurba; Barman, Pintu; Pal, Arup R.

    2016-04-01

    This report presents findings on biomimetic growth of hydroxyapatite (HAp) nanocrystals on Ti and sputtered TiO2 substrates. The possibility of TiO2 nanostructure as candidate materials for future biomedical applications has been explored through the comparison of microstructural and mechanical properties of bone like apatite grown on Ti and nano-TiO2 surfaces. Raman spectroscopy and x-ray diffraction studies reveal formation of carbonate apatite with apparent domain size in the nanoscale range. A better interaction at the nano-TiO2/nano-HAp interface due to higher interfacial area could promote the growth of bone like apatite. The crystal phases, crystallinity, and surface morphology of nano-TiO2 are considered as parameters to understand the nucleation and growth of apatite with different mechanical properties at the nanoscale. The methodology of x-ray line profile analysis encompasses deconvolution of merged peaks by preserving broadening due to nanosized HAp aggregates. The Young’s modulus of bone like apatite exhibits crystallographic directional dependence which suggests the presence of elastic anisotropy in bone like apatite. The lattice contraction in the c-direction is associated with the degree of carbonate substitution in the apatite lattice. The role of residual stress is critical for the lattice distortion of HAp deposited at physiological conditions of temperature and pH of human blood plasma. The ion concentration is crucial for the uniformity, crystallinity, and mechanical behaviour of the apatite.

  4. Biomimetic growth and substrate dependent mechanical properties of bone like apatite nucleated on Ti and magnetron sputtered TiO2 nanostructure

    International Nuclear Information System (INIS)

    Sarma, Bimal K; Das, Apurba; Barman, Pintu; Pal, Arup R

    2016-01-01

    This report presents findings on biomimetic growth of hydroxyapatite (HAp) nanocrystals on Ti and sputtered TiO 2 substrates. The possibility of TiO 2 nanostructure as candidate materials for future biomedical applications has been explored through the comparison of microstructural and mechanical properties of bone like apatite grown on Ti and nano-TiO 2 surfaces. Raman spectroscopy and x-ray diffraction studies reveal formation of carbonate apatite with apparent domain size in the nanoscale range. A better interaction at the nano-TiO 2 /nano-HAp interface due to higher interfacial area could promote the growth of bone like apatite. The crystal phases, crystallinity, and surface morphology of nano-TiO 2 are considered as parameters to understand the nucleation and growth of apatite with different mechanical properties at the nanoscale. The methodology of x-ray line profile analysis encompasses deconvolution of merged peaks by preserving broadening due to nanosized HAp aggregates. The Young’s modulus of bone like apatite exhibits crystallographic directional dependence which suggests the presence of elastic anisotropy in bone like apatite. The lattice contraction in the c-direction is associated with the degree of carbonate substitution in the apatite lattice. The role of residual stress is critical for the lattice distortion of HAp deposited at physiological conditions of temperature and pH of human blood plasma. The ion concentration is crucial for the uniformity, crystallinity, and mechanical behaviour of the apatite. (paper)

  5. Biomimetics: nature based innovation

    National Research Council Canada - National Science Library

    Bar-Cohen, Yoseph

    2012-01-01

    "Based on the concept that nature offers numerous sources of inspiration for inventions related to mechanisms, materials, processes, and algorithms, this book covers the topic of biomimetics and the inspired innovation...

  6. Nanocrystal quantum dots

    CERN Document Server

    Klimov, Victor I

    2010-01-01

    ""Soft"" Chemical Synthesis and Manipulation of Semiconductor Nanocrystals, J.A. Hollingsworth and V.I. Klimov Electronic Structure in Semiconductor Nanocrystals: Optical Experiment, D.J. NorrisFine Structure and Polarization Properties of Band-Edge Excitons in Semiconductor Nanocrystals, A.L. EfrosIntraband Spectroscopy and Dynamics of Colloidal Semiconductor Quantum Dots, P. Guyot-Sionnest, M. Shim, and C. WangMultiexciton Phenomena in Semiconductor Nanocrystals, V.I. KlimovOptical Dynamics in Single Semiconductor Quantum Do

  7. Biomimetic nanocrystalline apatite coatings synthesized by Matrix Assisted Pulsed Laser Evaporation for medical applications

    Energy Technology Data Exchange (ETDEWEB)

    Visan, A. [National Institute for Lasers, Plasma, and Radiation Physics, 409 Atomistilor Street, RO-77125, MG-36, Magurele-Ilfov (Romania); Grossin, D. [CIRIMAT – Carnot Institute, University of Toulouse, ENSIACET, 4 Allée Emile Monso, 31030 Toulouse Cedex 4 (France); Stefan, N.; Duta, L.; Miroiu, F.M. [National Institute for Lasers, Plasma, and Radiation Physics, 409 Atomistilor Street, RO-77125, MG-36, Magurele-Ilfov (Romania); Stan, G.E. [National Institute of Materials Physics, RO-077125, Magurele-Ilfov (Romania); Sopronyi, M.; Luculescu, C. [National Institute for Lasers, Plasma, and Radiation Physics, 409 Atomistilor Street, RO-77125, MG-36, Magurele-Ilfov (Romania); Freche, M.; Marsan, O.; Charvilat, C. [CIRIMAT – Carnot Institute, University of Toulouse, ENSIACET, 4 Allée Emile Monso, 31030 Toulouse Cedex 4 (France); Ciuca, S. [Politehnica University of Bucharest, Faculty of Materials Science and Engineering, Bucharest (Romania); Mihailescu, I.N., E-mail: ion.mihailescu@inflpr.ro [National Institute for Lasers, Plasma, and Radiation Physics, 409 Atomistilor Street, RO-77125, MG-36, Magurele-Ilfov (Romania)

    2014-02-15

    Highlights: • We report the deposition by MAPLE of biomimetic apatite coatings on Ti substrates. • This is the first report of MAPLE deposition of hydrated biomimetic apatite films. • Biomimetic apatite powder was synthesized by double decomposition process. • Non-apatitic environments, of high surface reactivity, are preserved post-deposition. • We got the MAPLE complete transfer as thin film of a hydrated, delicate material. -- Abstract: We report the deposition by Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique of biomimetic nanocrystalline apatite coatings on titanium substrates, with potential application in tissue engineering. The targets were prepared from metastable, nanometric, poorly crystalline apatite powders, analogous to mineral bone, synthesized through a biomimetic approach by double decomposition process. For the deposition of thin films, a KrF* excimer laser source was used (λ = 248 nm, τ{sub FWHM} ≤ 25 ns). The analyses revealed the existence, in synthesized powders, of labile non-apatitic mineral ions, associated with the formation of a hydrated layer at the surface of the nanocrystals. The thin film analyses showed that the structural and chemical nature of the nanocrystalline apatite was prevalently preserved. The perpetuation of the non-apatitic environments was also observed. The study indicated that MAPLE is a suitable technique for the congruent transfer of a delicate material, such as the biomimetic hydrated nanohydroxyapatite.

  8. Biomimetic nanocrystalline apatite coatings synthesized by Matrix Assisted Pulsed Laser Evaporation for medical applications

    International Nuclear Information System (INIS)

    Visan, A.; Grossin, D.; Stefan, N.; Duta, L.; Miroiu, F.M.; Stan, G.E.; Sopronyi, M.; Luculescu, C.; Freche, M.; Marsan, O.; Charvilat, C.; Ciuca, S.; Mihailescu, I.N.

    2014-01-01

    Highlights: • We report the deposition by MAPLE of biomimetic apatite coatings on Ti substrates. • This is the first report of MAPLE deposition of hydrated biomimetic apatite films. • Biomimetic apatite powder was synthesized by double decomposition process. • Non-apatitic environments, of high surface reactivity, are preserved post-deposition. • We got the MAPLE complete transfer as thin film of a hydrated, delicate material. -- Abstract: We report the deposition by Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique of biomimetic nanocrystalline apatite coatings on titanium substrates, with potential application in tissue engineering. The targets were prepared from metastable, nanometric, poorly crystalline apatite powders, analogous to mineral bone, synthesized through a biomimetic approach by double decomposition process. For the deposition of thin films, a KrF* excimer laser source was used (λ = 248 nm, τ FWHM ≤ 25 ns). The analyses revealed the existence, in synthesized powders, of labile non-apatitic mineral ions, associated with the formation of a hydrated layer at the surface of the nanocrystals. The thin film analyses showed that the structural and chemical nature of the nanocrystalline apatite was prevalently preserved. The perpetuation of the non-apatitic environments was also observed. The study indicated that MAPLE is a suitable technique for the congruent transfer of a delicate material, such as the biomimetic hydrated nanohydroxyapatite

  9. Different properties exhibited on the two typical crystal faces of hydroxyapatite in a simulated body environment

    International Nuclear Information System (INIS)

    Hagio, T; Iwai, K; Tanase, T; Akiyama, J; Asai, S

    2009-01-01

    Hydroxyapatite is a main mineral constituent of hard tissues and is extensively used as a biomaterial in the medical field. Hydroxyapatite exhibits anisotropic chemical properties on its two typical crystal faces, the a-face and c-face, due to its hexagonal crystal structure. In polycrystalline bodies, such anisotropy can be enhanced by controlling the crystal orientation. Hydroxyapatite nanocrystals that constitute long bones also form a crystal oriented structure. Therefore, clarification of the difference between the properties of a-face and c-face in hydroxyapatite using in vitro experiments is useful to understand the structure and function of actual hard tissues. Hydroxyapatite ceramics with controlled crystal orientation were prepared by a slip casting method under application of a magnetic field. The fabricated hydroxyapatite ceramics had surfaces consisting mainly of a-face, or otherwise c-face hydroxyapatite. These hydroxyapatite ceramics were immersed into simulated body fluids to investigate the difference in bioactivity. The precipitation behavior observed on the surface of each hydroxyapatite ceramic was different. The thickness of the precipitate was increased and formed earlier on the HAp c-face compared to that on the a-face.

  10. Different properties exhibited on the two typical crystal faces of hydroxyapatite in a simulated body environment

    Energy Technology Data Exchange (ETDEWEB)

    Hagio, T; Iwai, K [Department of Materials, Physics and Energy Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603 (Japan); Tanase, T [Toho Gas Corporation, 19-18 Sakurada-cho, Atsuta-ku, Nagoya, 456-8511 (Japan); Akiyama, J [Institute for Molecular Science, National Institute of Natural Sciences, 38 Nishigonaka, Myodaiji, Okazaki, 444-8585 (Japan); Asai, S [Innovation Plaza Tokai Japan Science and Technology Agency, 23-1 Ahara-cho, Minami-ku, Nagoya, 457-0063 (Japan)], E-mail: hagio.takeshi@h.mbox.nagoya-u.ac.jp

    2009-03-01

    Hydroxyapatite is a main mineral constituent of hard tissues and is extensively used as a biomaterial in the medical field. Hydroxyapatite exhibits anisotropic chemical properties on its two typical crystal faces, the a-face and c-face, due to its hexagonal crystal structure. In polycrystalline bodies, such anisotropy can be enhanced by controlling the crystal orientation. Hydroxyapatite nanocrystals that constitute long bones also form a crystal oriented structure. Therefore, clarification of the difference between the properties of a-face and c-face in hydroxyapatite using in vitro experiments is useful to understand the structure and function of actual hard tissues. Hydroxyapatite ceramics with controlled crystal orientation were prepared by a slip casting method under application of a magnetic field. The fabricated hydroxyapatite ceramics had surfaces consisting mainly of a-face, or otherwise c-face hydroxyapatite. These hydroxyapatite ceramics were immersed into simulated body fluids to investigate the difference in bioactivity. The precipitation behavior observed on the surface of each hydroxyapatite ceramic was different. The thickness of the precipitate was increased and formed earlier on the HAp c-face compared to that on the a-face.

  11. 3D Biomimetic Magnetic Structures for Static Magnetic Field Stimulation of Osteogenesis

    OpenAIRE

    Irina Alexandra Paun; Roxana Cristina Popescu; Bogdan Stefanita Calin; Cosmin Catalin Mustaciosu; Maria Dinescu; Catalin Romeo Luculescu

    2018-01-01

    We designed, fabricated and optimized 3D biomimetic magnetic structures that stimulate the osteogenesis in static magnetic fields. The structures were fabricated by direct laser writing via two-photon polymerization of IP-L780 photopolymer and were based on ellipsoidal, hexagonal units organized in a multilayered architecture. The magnetic activity of the structures was assured by coating with a thin layer of collagen-chitosan-hydroxyapatite-magnetic nanoparticles composite. In vitro experime...

  12. Biomimetic Materials for Pathogen Neutralization

    National Research Council Canada - National Science Library

    Ingber, Donald

    1997-01-01

    ...) and polymer chemistry fabrication technologies for the production of synthetic 'biomimetic' materials that exhibit the mechanical responsiveness and biochemical processing capabilities of living cells and tissues...

  13. Amelogenin and Enamel Biomimetics

    Science.gov (United States)

    Ruan, Qichao; Moradian-Oldak, Janet

    2015-01-01

    Mature tooth enamel is acellular and does not regenerate itself. Developing technologies that rebuild tooth enamel and preserve tooth structure is therefore of great interest. Considering the importance of amelogenin protein in dental enamel formation, its ability to control apatite mineralization in vitro, and its potential to be applied in fabrication of future bio-inspired dental material this review focuses on two major subjects: amelogenin and enamel biomimetics. We review the most recent findings on amelogenin secondary and tertiary structural properties with a focus on its interactions with different targets including other enamel proteins, apatite mineral, and phospholipids. Following a brief overview of enamel hierarchical structure and its mechanical properties we will present the state-of-the-art strategies in the biomimetic reconstruction of human enamel. PMID:26251723

  14. Biogenic Hydroxyapatite: A New Material for the Preservation and Restoration of the Built Environment.

    Science.gov (United States)

    Turner, Ronald J; Renshaw, Joanna C; Hamilton, Andrea

    2017-09-20

    Ordinary Portland cement (OPC) is by weight the world's most produced man-made material and is used in a variety of applications in environments ranging from buildings, to nuclear wasteforms, and within the human body. In this paper, we present for the first time the direct deposition of biogenic hydroxyapatite onto the surface of OPC in a synergistic process which uses the composition of the cement substrate. This hydroxyapatite is very similar to that found in nature, having a similar crystallite size, iron and carbonate substitution, and a semi-crystalline structure. Hydroxyapatites with such a structure are known to be mechanically stronger and more biocompatible than synthetic or biomimetic hydroxyapatites. The formation of this biogenic hydroxyapatite coating therefore has significance in a range of contexts. In medicine, hydroxyapatite coatings are linked to improved biocompatibility of ceramic implant materials. In the built environment, hydroxyapatite coatings have been proposed for the consolidation and protection of sculptural materials such as marble and limestone, with biogenic hydroxyapatites having reduced solubility compared to synthetic apatites. Hydroxyapatites have also been established as effective for the adsorption and remediation of environmental contaminants such as radionuclides and heavy metals. We identify that in addition to providing a biofilm scaffold for nucleation, the metabolic activity of Pseudomonas fluorescens increases the pH of the growth medium to a suitable level for hydroxyapatite formation. The generated ammonia reacts with phosphate in the growth medium, producing ammonium phosphates which are a precursor to the formation of hydroxyapatite under conditions of ambient temperature and pressure. Subsequently, this biogenic deposition process takes place in a simple reaction system under mild chemical conditions and is cheap and easy to apply to fragile biological or architectural surfaces.

  15. Biomimetic magnetic nanoparticles

    OpenAIRE

    Klem, Michael T.; Young, Mark; Douglas, Trevor

    2005-01-01

    Magnetic nanoparticles are of considerable interest because of their potential use in high-density memory devices, spintronics, and applications in diagnostic medicine. The conditions for synthesis of these materials are often complicated by their high reaction temperatures, costly reagents, and post-processing requirements. Practical applications of magnetic nanoparticles will require the development of alternate synthetic strategies that can overcome these impediments. Biomimetic approaches...

  16. A Biomimetic Haptic Sensor

    OpenAIRE

    Ben Mitchinson; Ian Gilhespy; Chris Melhuish; Mokhtar Nibouche; Tony J. Prescott; Anthony G. Pipe; Martin J. Pearson

    2008-01-01

    The design and implementation of the periphery of an artificial whisker sensory system is presented. It has been developed by adopting a biomimetic approach to model the structure and function of rodent facial vibrissae. The artificial vibrissae have been formed using composite materials and have the ability to be actively moved or whisked. The sensory structures at the root of real vibrissae has been modelled and implemented using micro strain gauges and Digital Signal Processors. The primar...

  17. Biomimetic hydrogel materials

    Science.gov (United States)

    Bertozzi, Carolyn; Mukkamala, Ravindranath; Chen, Qing; Hu, Hopin; Baude, Dominique

    2000-01-01

    Novel biomimetic hydrogel materials and methods for their preparation. Hydrogels containing acrylamide-functionalized carbohydrate, sulfoxide, sulfide or sulfone copolymerized with a hydrophilic or hydrophobic copolymerizing material selected from the group consisting of an acrylamide, methacrylamide, acrylate, methacrylate, vinyl and a derivative thereof present in concentration from about 1 to about 99 wt %. and methods for their preparation. The method of use of the new hydrogels for fabrication of soft contact lenses and biomedical implants.

  18. Comparison of hydroxyapatite and dental enamel for testing shear bond strengths.

    Science.gov (United States)

    Imthiaz, Nishat; Georgiou, George; Moles, David R; Jones, Steven P

    2008-05-01

    To investigate the feasibility of using artificial hydroxyapatite as a future biomimetic laboratory substitute for human enamel in orthodontic bond strength testing by comparing the shear bond strengths and nature of failure of brackets bonded to samples of hydroxyapatite and enamel. One hundred and fifty hydroxyapatite discs were prepared by compression at 20 tons and fired in a furnace at 1300 degrees C. One hundred and five enamel samples were prepared from the buccal and palatal/lingual surfaces of healthy premolars extracted for orthodontic purposes. Orthodontic brackets were bonded to each sample and these were subjected to shear bond strength testing using a custom-made jig mounted in an Instron Universal Testing Machine. The force value at bond failure was obtained, together with the nature of failure which was assessed using the Adhesive Remnant Index. The mean shear bond strength for the enamel samples was 16.62 MPa (95 per cent CI: 15.26, 17.98) and for the hydroxyapatite samples 20.83 MPa (95 per cent CI: 19.68, 21.98). The difference between the two samples was statistically significant (p enamel samples scored 2 or 3, while 49 per cent of the hydroxyapatite samples scored 0 or 1. Hydroxyapatite was an effective biomimetic substrate for bond strength testing with a mean shear bond strength value (20.83 MPa) at the upper end of the normal range attributed to enamel (15-20 MPa). Although the difference between the shear bond strengths for hydroxyapatite and enamel was statistically significant, hydroxyapatite could be used as an alternative to enamel for comparative laboratory studies until a closer alternative is found. This would eliminate the need for extracted teeth to be collected. However, it should be used with caution for quantitative studies where true bond strengths are to be investigated.

  19. Highly phosphorescent hollow fibers inner-coated with tungstate nanocrystals

    Science.gov (United States)

    Ng, Pui Fai; Bai, Gongxun; Si, Liping; Lee, Ka I.; Hao, Jianhua; Xin, John H.; Fei, Bin

    2017-12-01

    In order to develop luminescent microtubes from natural fibers, a facile biomimetic mineralization method was designed to introduce the CaWO4-based nanocrystals into kapok lumens. The structure, composition, and luminescence properties of resultant fibers were investigated with microscopes, x-ray diffraction, thermogravimetric analysis, and fluorescence spectrometry. The yield of tungstate crystals inside kapok was significantly promoted with a process at high temperature and pressure—the hydrothermal treatment. The tungstate crystals grown on the inner wall of kapok fibers showed the same crystal structure with those naked powders, but smaller in crystal size. The resultant fiber assemblies demonstrated reduced phosphorescence intensity in comparison to the naked tungstate powders. However, the fibers gave more stable luminescence than the naked powders in wet condition. This approach explored the possibility of decorating natural fibers with high load of nanocrystals, hinting potential applications in anti-counterfeit labels, security textiles, and even flexible and soft optical devices.

  20. Biomimetic materials for controlling bone cell responses.

    Science.gov (United States)

    Drevelle, Olivier; Faucheux, Nathalie

    2013-01-01

    Bone defects that cannot "heal spontaneously during life" will become an ever greater health problem as populations age. Harvesting autografts has several drawbacks, such as pain and morbidity at both donor and acceptor sites, the limited quantity of material available, and frequently its inappropriate shape. Researchers have therefore developed alternative strategies that involve biomaterials to fill bone defects. These biomaterials must be biocompatible and interact with the surrounding bone tissue to allow their colonization by bone cells and blood vessels. The latest generation biomaterials are not inert; they control cell responses like adhesion, proliferation and differentiation. These biomaterials are called biomimetic materials. This review focuses on the development of third generation materials. We first briefly describe the bone tissue with its cells and matrix, and then how bone cells interact with the extracellular matrix. The next section covers the materials currently used to repair bone defects. Finally, we describe the strategies employed to modify the surface of materials, such as coating with hydroxyapatite and grafting biomolecules.

  1. Biomimetic nanoparticles for inflammation targeting

    Directory of Open Access Journals (Sweden)

    Kai Jin

    2018-01-01

    Full Text Available There have been many recent exciting developments in biomimetic nanoparticles for biomedical applications. Inflammation, a protective response involving immune cells, blood vessels, and molecular mediators directed against harmful stimuli, is closely associated with many human diseases. As a result, biomimetic nanoparticles mimicking immune cells can help achieve molecular imaging and precise drug delivery to these inflammatory sites. This review is focused on inflammation-targeting biomimetic nanoparticles and will provide an in-depth look at the design of these nanoparticles to maximize their benefits for disease diagnosis and treatment.

  2. Biomimetics in Tribology

    Science.gov (United States)

    Gebeshuber, I. C.; Majlis, B. Y.; Stachelberger, H.

    Science currently goes through a major change. Biology is evolving as new Leitwissenschaft, with more and more causation and natural laws being uncovered. The term `technoscience' denotes the field where science and technology are inseparably interconnected, the trend goes from papers to patents, and the scientific `search for truth' is increasingly replaced by search for applications with a potential economic value. Biomimetics, i.e. knowledge transfer from biology to technology, is a field that has the potential to drive major technical advances. The biomimetic approach might change the research landscape and the engineering culture dramatically, by the blending of disciplines. It might substantially support successful mastering of current tribological challenges: friction, adhesion, lubrication and wear in devices and systems from the meter to the nanometer scale. A highly successful method in biomimectics, the biomimicry innovation method, is applied in this chapter to identify nature's best practices regarding two key issues in tribology: maintenance of the physical integrity of a system, and permanent as well as temporary attachment. The best practices identified comprise highly diverse organisms and processes and are presented in a number of tables with detailed references.

  3. Simultaneous control of nanocrystal size and nanocrystal ...

    Indian Academy of Sciences (India)

    applications such as a photo-sensor [11]. Thus, it is desirable to have, not only a control on the size of the nanocrystals, but also an independent tunability of the ... 1-thioglycerol) in 25 ml methanol under inert atmosphere. 10 ml of 0.2 M sodium sulfide solution is then added to the reaction mixture dropwise and the reaction.

  4. Fabrication, characterization, and in vitro study of zinc substituted hydroxyapatite/silk fibroin composite coatings on titanium for biomedical applications.

    Science.gov (United States)

    Zhong, Zhenyu; Ma, Jun

    2017-09-01

    Zinc substituted hydroxyapatite/silk fibroin composite coatings were deposited on titanium substrates at room temperature by electrophoretic deposition. Microscopic characterization of the synthesized composite nanoparticles revealed that the particle size ranged 50-200 nm, which increased a little after zinc substitution. The obtained coatings maintained the phase of hydroxyapatite and they could induce fast apatite formation in simulated body fluid, indicating high bone activity. The cell culturing results showed that the biomimetic hydroxyapatite coatings could regulate adhesion, spreading, and proliferation of osteoblastic cells. Furthermore, the biological behavior of the zinc substituted hydroxyapatite coatings was found to be better than the bare titanium without coatings and hydroxyapatite coatings without zinc, increasing MC3T1-E1 cell differentiation in alkaline phosphatase expression.

  5. A Biomimetic Haptic Sensor

    Directory of Open Access Journals (Sweden)

    Ben Mitchinson

    2008-11-01

    Full Text Available The design and implementation of the periphery of an artificial whisker sensory system is presented. It has been developed by adopting a biomimetic approach to model the structure and function of rodent facial vibrissae. The artificial vibrissae have been formed using composite materials and have the ability to be actively moved or whisked. The sensory structures at the root of real vibrissae has been modelled and implemented using micro strain gauges and Digital Signal Processors. The primary afferents and vibrissal trigeminal ganglion have been modelled using empirical data taken from electrophysiological measurements, and implemented in real-time using a Field Programmable Gate Array. Pipelining techniques were employed to maximise the utility of the FPGA hardware. The system is to be integrated into a more complete whisker sensory model, including neural structures within the central nervous system, which can be used to orient a mobile robot.

  6. A Biomimetic Haptic Sensor

    Directory of Open Access Journals (Sweden)

    Martin J. Pearson

    2005-12-01

    Full Text Available The design and implementation of the periphery of an artificial whisker sensory system is presented. It has been developed by adopting a biomimetic approach to model the structure and function of rodent facial vibrissae. The artificial vibrissae have been formed using composite materials and have the ability to be actively moved or whisked. The sensory structures at the root of real vibrissae has been modelled and implemented using micro strain gauges and Digital Signal Processors. The primary afferents and vibrissal trigeminal ganglion have been modelled using empirical data taken from electrophysiological measurements, and implemented in real-time using a Field Programmable Gate Array. Pipelining techniques were employed to maximise the utility of the FPGA hardware. The system is to be integrated into a more complete whisker sensory model, including neural structures within the central nervous system, which can be used to orient a mobile robot.

  7. Novel synthesis strategy for composite hydrogel of collagen/hydroxyapatite-microsphere originating from conversion of CaCO3 templates.

    Science.gov (United States)

    Wei, Qingrong; Lu, Jian; Wang, Qiaoying; Fan, Hongsong; Zhang, Xingdong

    2015-03-20

    Inspired by coralline-derived hydroxyapatite, we designed a methodological route to synthesize carbonated-hydroxyapatite microspheres from the conversion of CaCO3 spherulite templates within a collagen matrix under mild conditions and thus constructed the composite hydrogel of collagen/hydroxyapatite-microspheres. Fourier transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) were employed to confirm the successful generation of the carbonated hydroxyapatite phase originating from CaCO3, and the ratios of calcium to phosphate were tracked over time. Variations in the weight portion of the components in the hybrid gels before and after the phase transformation of the CaCO3 templates were identified via thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) shows these composite hydrogels have a unique multiscale microstructure consisting of a collagen nanofibril network and hydroxyapatite microspheres. The relationship between the hydroxyapatite nanocrystals and the collagen fibrils was revealed by transmission electron microscopy (TEM) in detail, and the selected area electron diffraction (SAED) pattern further confirmed the results of the XRD analyses which show the typical low crystallinity of the generated hydroxyapatite. This smart synthesis strategy achieved the simultaneous construction of microscale hydroxyapatite particles and collagen fibrillar hydrogel, and appears to provide a novel route to explore an advanced functional hydrogel materials with promising potentials for applications in bone tissue engineering and reconstruction medicine.

  8. Nanocrystals Technology for Pharmaceutical Science.

    Science.gov (United States)

    Cheng, Zhongyao; Lian, Yumei; Kamal, Zul; Ma, Xin; Chen, Jianjun; Zhou, Xinbo; Su, Jing; Qiu, Mingfeng

    2018-05-17

    Nanocrystals technology is a promising method for improving the dissolution rate and enhancing the bioavailability of poorly soluble drugs. In recent years, it has been developing rapidly and applied to drug research and engineering. Nanocrystal drugs can be formulated into various dosage forms. This review mainly focused on the nanocrystals technology and its application in pharmaceutical science. Firstly, different preparation methods of nanocrystal technology and the characterization of nanocrystal drugs are briefly described. Secondly, the application of nanocrystals technology in pharmaceutical science is mainly discussed followed by the introduction of sustained release formulations. Then, the scaling up process, marketed nanocrystal drug products and regulatory aspects about nanodrugs are summarized. Finally, the specific challenges and opportunities of nanocrystals technology for pharmaceutical science are summarized and discussed. This review will provide a comprehensive guide for scientists and engineers in the field of pharmaceutical science and biochemical engineering. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  9. Optimization of a biomimetic bone cement: role of DCPD.

    Science.gov (United States)

    Panzavolta, Silvia; Bracci, Barbara; Rubini, Katia; Bigi, Adriana

    2011-08-01

    We previously proposed a biomimetic α-tricalcium phosphate (α-TCP) bone cement where gelatin controls the transformation of α-TCP into calcium deficient hydroxyapatite (CDHA), leading to improved mechanical properties. In this study we investigated the setting and hardening processes of biomimetic cements containing increasing amounts of CaHPO(4)·2H2O (DCPD) (0, 2.5, 5, 10, 15 wt.%), with the aim to optimize composition. Both initial and final setting times increased significantly when DCPD content accounts for 10 wt.%, whereas cements containing 15 wt.% DCPD did not set at all. Differential scanning calorimetry (DSC), X-ray diffraction (XRD), thermogravimetry (TG) and scanning electron microscopy (SEM) investigations were performed on samples maintained in physiological solution for different times. DCPD dissolution starts soon after cement preparation, but the rate of transformation decreases on increasing DCPD initial content in the samples. The rate of α-TCP to CDHA conversion during hardening decreases on increasing DCPD initial content. Moreover, the presence of DCPD prevents gelatin release during hardening. The combined effects of gelatin and DCPD on the rate of CDHA formation and porosity lead to significantly improved mechanical properties, with the best composition displaying a compressive strength of 35 MPa and a Young modulus of 1600 MPa. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Nanocrystal Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Gur, Ilan [Univ. of California, Berkeley, CA (United States)

    2006-01-01

    This dissertation presents the results of a research agenda aimed at improving integration and stability in nanocrystal-based solar cells through advances in active materials and device architectures. The introduction of 3-dimensional nanocrystals illustrates the potential for improving transport and percolation in hybrid solar cells and enables novel fabrication methods for optimizing integration in these systems. Fabricating cells by sequential deposition allows for solution-based assembly of hybrid composites with controlled and well-characterized dispersion and electrode contact. Hyperbranched nanocrystals emerge as a nearly ideal building block for hybrid cells, allowing the controlled morphologies targeted by templated approaches to be achieved in an easily fabricated solution-cast device. In addition to offering practical benefits to device processing, these approaches offer fundamental insight into the operation of hybrid solar cells, shedding light on key phenomena such as the roles of electrode-contact and percolation behavior in these cells. Finally, all-inorganic nanocrystal solar cells are presented as a wholly new cell concept, illustrating that donor-acceptor charge transfer and directed carrier diffusion can be utilized in a system with no organic components, and that nanocrystals may act as building blocks for efficient, stable, and low-cost thin-film solar cells.

  11. In vitro electromagnetically stimulated SAOS-2 osteoblasts inside porous hydroxyapatite

    Science.gov (United States)

    Fassina, Lorenzo; Saino, Enrica; Sbarra, Maria Sonia; Visai, Livia; De Angelis, Maria Gabriella Cusella; Magenes, Giovanni; Benazzo, Francesco

    2009-01-01

    One of the key challenges in reconstructive bone surgery is to provide living constructs that possess the ability to integrate in the surrounding tissue. Bone graft substitutes, such as autografts, allografts, xenografts, and biomaterials have been widely used to heal critical-size long bone defects due to trauma, tumor resection, congenital deformity, and tissue degeneration. In particular, porous hydroxyapatite is widely used in reconstructive bone surgery owing to its biocompatibility. In addition, the in vitro modification of hydroxyapatite with osteogenic signals enhances the tissue regeneration in vivo, suggesting that the biomaterial modification could play an important role in tissue engineering. In this study we have followed a biomimetic strategy where electromagnetically stimulated SAOS-2 human osteoblasts proliferated and built their extracellular matrix inside a porous hydroxyapatite scaffold. The electromagnetic stimulus had the following parameters: intensity of the magnetic field equal to 2 mT, amplitude of the induced electric tension equal to 5 mV, frequency of 75 Hz, and pulse duration of 1.3 ms. In comparison with control conditions, the electromagnetic stimulus increased the cell proliferation and the surface coating with bone proteins (decorin, osteocalcin, osteopontin, type-I collagen, and type-III collagen). The physical stimulus aimed at obtaining a better modification of the biomaterial internal surface in terms of cell colonization and coating with bone matrix. PMID:19827111

  12. Synthesis of hydroxyapatite in the presence of biologically significant molecules

    International Nuclear Information System (INIS)

    Alvarez, R.; Evans, L.A.

    2000-01-01

    In bone mineralization non-collagenous phosphoproteins containing polycarboxylate sequences are thought to control crystal nucleation and to subsequently modify crystal growth. Invertebrate calcified tissues may also contain significant amounts of phosphoserine and/or acidic amino acid residues together with chitin (a polysaccharide). The present study investigated the effect of synthetic phosphorylated compounds as well as monomeric/polymeric carboxylic acid compounds on the formation of hydroxyapatite (HAp) under conditions of physiological pH, temperature and ionic strength. Poly-L-sodium aspartate was found to have the greatest inhibitory effect; only octacalcium phosphate (a known precursor of hydroxyapatite) could be detected in the presence of this polymer. Resultant minerals showed a variety of aggregation states. The biomimetically formed calcium phosphate minerals were identified and characterised by a variety of analytical thechniques, including laser Raman, Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy and x-ray diffraction analysis. In addition, a series of experiments were performed to induce the formation of HAp on biogenic substrates, such as chitin and its derivatives, chitosan, reconstituted chitin and phosphorylated chitin. Granular aggregates of hydroxyapatite could be induced to form directly on phosphorylated chitin surfaces, but not on other biogenically-derived substrates. Copyright (2000) The Australian Ceramic Society

  13. Biomimetic architectures by plasma processing fabrication and applications

    CERN Document Server

    Chattopadhyay, Surojit

    2014-01-01

    Photonic structures in the animal kingdom: valuable inspirations for bio-mimetic applications. Moth eye-type anti-reflecting nanostructures by an electron cyclotron resonance plasma. Plasma-processed biomimetic nano/microstructures. Wetting properties of natural and plasma processed biomimetic surfaces. Biomimetic superhydrophobic surface by plasma processing. Biomimetic interfaces of plasma modified titanium alloy.

  14. Hydroxyapatite synthesis using EDTA

    Science.gov (United States)

    Kang, Nak Heon; Kim, Soon Je; Song, Seung Han; Choi, Sang mun; Choi, Sik Young; Kim, Youn Jung

    2013-01-01

    Bone comprises structure of body and is consisted of inorganic substances. It exists in an organic structure in the body. Even though it is firm and has self healing mechanism, it can be damaged by trauma, cancer, or bone diseases. Allograft can be an alternative solution for autologous bone graft. Hydroxyapatite(Ca10(PO4)6(OH)2), an excellent candidate for allograft, can be applied to bone defect area. There are several methods to produce hydroxyapatite, however economical cost and time consuming make the production difficult. In this study we synthesized the hydroxyapatite with Ethyenediamine tetraacetic acid. Freeze Dried Bone Allograft(Hans Biomed) was used to be a control group. Synthesized hydroxyapatite was a rod shape, white powdery type substance with 2 ~ 5 μm length and 0.5 ~ 1 μm width. X-ray diffraction showed the highest sharp peak at 32° and high peaks at 25.8°, 39.8°, 46.8°, 49.5°, and 64.0° indicating a similar substance to the freeze Dried Bone Allograft. 3 days after the cell growth of synthesized hydroxyapatite showed 1.5 fold more than the Bone Allograft. Cellular and media alkaline phosphate activity increased similar to the bone alloagraft. In this study we came up with a new method to produce the hydroxyapatite. It is a convenient method that can be held in room temperature and low pressure. Also the the product can be manufactured in large quantity. It can be also transformed into scaffold structure which will perform a stronger configuration. The manufacturing method will help the bony defect patients and make future medical products. PMID:23714942

  15. Hydroxyapatite synthesis using EDTA.

    Science.gov (United States)

    Kang, Nak Heon; Kim, Soon Je; Song, Seung Han; Choi, Sang mun; Choi, Sik Young; Kim, Youn Jung

    2013-05-01

    Bone comprises structure of the body and consisted of inorganic substances. It exists in an organic structure in the body. Even though it is firm and has self-healing mechanism, it can be damaged by trauma, cancer, or bone diseases. Allograft can be an alternative solution for autologous bone graft. Hydroxyapatite (Ca10(PO4)6(OH)2), an excellent candidate for allograft, can be applied to bone defect area. There are several methods to produce hydroxyapatite; however, economical cost and being time consuming make the production difficult. In this study, we synthesized hydroxyapatite with EDTA. Freeze-dried bone allograft (Hans Biomed) was used as the control group. Synthesized hydroxyapatite was a rod-shaped, white powdery substance with 2- to 5-μm length and 0.5- to 1-μm width. X-ray diffraction showed the highest sharp peak at 32°C and high peaks at 25.8°C, 39.8°C, 46.8°C, 49.5°C, and 64.0°C, indicating a similar substance to the freeze-dried bone allograft. After 3 days, the cell growth of synthesized hydroxyapatite showed 1.5-fold more than did the bone allograft. Cellular and media alkaline phosphate activity increased similar to the bone allograft. In this study, we came up with a new method to produce the hydroxyapatite. It is a convenient method that can be held in room temperature and low pressure. Also, the product can be manufactured in large quantity. It can be also transformed into scaffold structure, which will perform a stronger configuration. The manufacturing method will help the bony defect patients and make future medical products.

  16. Monodisperse selenium-substituted hydroxyapatite: Controllable synthesis and biocompatibility

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Jianpeng [School of Civil Engineering, Xi' an University of Architecture and Technology, Shaanxi 710055 (China); Shaanxi Key Laboratory of Degradable Biomedical Materials, Shaanxi R& D Center of Biomaterials and Fermentation Engineering, School of Chemical and Engineering, Northwest University, Xi' an, 710069 (China); Zheng, Xiaoyan; Li, Hui; Fan, Daidi [Shaanxi Key Laboratory of Degradable Biomedical Materials, Shaanxi R& D Center of Biomaterials and Fermentation Engineering, School of Chemical and Engineering, Northwest University, Xi' an, 710069 (China); Song, Zhanping [School of Civil Engineering, Xi' an University of Architecture and Technology, Shaanxi 710055 (China); Ma, Haixia [Shaanxi Key Laboratory of Degradable Biomedical Materials, Shaanxi R& D Center of Biomaterials and Fermentation Engineering, School of Chemical and Engineering, Northwest University, Xi' an, 710069 (China); Hua, Xiufu, E-mail: hua_xiufu@163.com [Department of Scientific Research and Development, Tsinghua University, Beijing 100084 (China); Hui, Junfeng, E-mail: huijunfeng@126.com [Shaanxi Key Laboratory of Degradable Biomedical Materials, Shaanxi R& D Center of Biomaterials and Fermentation Engineering, School of Chemical and Engineering, Northwest University, Xi' an, 710069 (China)

    2017-04-01

    Hydroxyapatite (HA) is the major inorganic component of natural bone tissue. As an essential trace element, selenium involves in antioxidation and anticancer of human body. So far, ion-doped hydroxyapatites (HAs) are widely investigated owing to their great applications in field of biomaterial, biological labeling. In this paper, series of monodisperse HA doped with SeO{sub 3}{sup 2−} (SeHA) was successfully synthesized based on the liquid–solid–solution (LSS) strategy. The obtained samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and energy-dispersive spectrometer (EDS). The results indicated that the SeO{sub 3}{sup 2−} doping level of the Se/(P + Se) molar ratio of 0– 0.4 can be requisitely controlled, and the morphology of SeHA nanoparticles varied from nanorods to nanoneedles with increasing Se/(P + Se) molar ratio. Significantly, the as-synthesized SeHA nanocrystals exhibit a low cytotoxicity for osteoblastic cells, showing exciting potentials for application in artificial scaffold materials inhibiting of tumor growth in bone. - Highlights: • Series of SeO{sub 3}{sup 2−} doped HA nanorods or/and nanoneedles were successfully synthesized. • The morphology of the HA nanocrystals can be easily controlled by changing the Se/(P + Se) molar ratio. • The as-synthesized SeHA nanocrystals exhibit a low cytotoxicity for osteoblastic cells. • Showing exciting potentials for application in artificial scaffold materials inhibiting of tumor growth in bone.

  17. Monodisperse selenium-substituted hydroxyapatite: Controllable synthesis and biocompatibility

    International Nuclear Information System (INIS)

    Sun, Jianpeng; Zheng, Xiaoyan; Li, Hui; Fan, Daidi; Song, Zhanping; Ma, Haixia; Hua, Xiufu; Hui, Junfeng

    2017-01-01

    Hydroxyapatite (HA) is the major inorganic component of natural bone tissue. As an essential trace element, selenium involves in antioxidation and anticancer of human body. So far, ion-doped hydroxyapatites (HAs) are widely investigated owing to their great applications in field of biomaterial, biological labeling. In this paper, series of monodisperse HA doped with SeO 3 2− (SeHA) was successfully synthesized based on the liquid–solid–solution (LSS) strategy. The obtained samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and energy-dispersive spectrometer (EDS). The results indicated that the SeO 3 2− doping level of the Se/(P + Se) molar ratio of 0– 0.4 can be requisitely controlled, and the morphology of SeHA nanoparticles varied from nanorods to nanoneedles with increasing Se/(P + Se) molar ratio. Significantly, the as-synthesized SeHA nanocrystals exhibit a low cytotoxicity for osteoblastic cells, showing exciting potentials for application in artificial scaffold materials inhibiting of tumor growth in bone. - Highlights: • Series of SeO 3 2− doped HA nanorods or/and nanoneedles were successfully synthesized. • The morphology of the HA nanocrystals can be easily controlled by changing the Se/(P + Se) molar ratio. • The as-synthesized SeHA nanocrystals exhibit a low cytotoxicity for osteoblastic cells. • Showing exciting potentials for application in artificial scaffold materials inhibiting of tumor growth in bone

  18. Bio-mimetic Flow Control

    Science.gov (United States)

    Choi, Haecheon

    2009-11-01

    Bio-mimetic engineering or bio-mimetics is the application of biological methods and systems found in nature to the study and design of engineering systems and modern technology (from Wikipedia). The concept itself is old, but successful developments have been made recently, especially in the research field of flow control. The objective of flow control based on the bio-mimetic approach is to develop novel concepts for reducing drag, increasing lift and enhancing aerodynamic performance. For skin friction reduction, a few ideas have been suggested such as the riblet from shark, compliant surface from dolphin, microbubble injection and multiple front-body curvature from penguin, and V-shaped protrusion from sailfish. For form drag reduction, several new attempts have been also made recently. Examples include the V-shaped spanwise grooves from saguaro cactus, overall shape of box fish, longitudinal grooves on scallop shell, bill of swordfish, hooked comb on owl wing, trailing-edge protrusion on dragonfly wing, and fillet. For the enhancement of aerodynamic performance, focuses have been made on the birds, fish and insects: e.g., double layered feather of landing bird, leading-edge serration of humpback-whale flipper, pectoral fin of flying fish, long tail on swallowtail-butterfly wing, wing flapping motion of dragonfly, and alula in birds. Living animals adapt their bodies to better performance in multi purposes, but engineering requires single purpose in most cases. Therefore, bio-mimetic approaches often produce excellent results more than expected. However, they are sometimes based on people's wrong understanding of nature and produce unwanted results. Successes and failures from bio-mimetic approaches in flow control will be discussed in the presentation.

  19. Sorting fluorescent nanocrystals with DNA

    Energy Technology Data Exchange (ETDEWEB)

    Gerion, Daniele; Parak, Wolfgang J.; Williams, Shara C.; Zanchet, Daniela; Micheel, Christine M.; Alivisatos, A. Paul

    2001-12-10

    Semiconductor nanocrystals with narrow and tunable fluorescence are covalently linked to oligonucleotides. These biocompounds retain the properties of both nanocrystals and DNA. Therefore, different sequences of DNA can be coded with nanocrystals and still preserve their ability to hybridize to their complements. We report the case where four different sequences of DNA are linked to four nanocrystal samples having different colors of emission in the range of 530-640 nm. When the DNA-nanocrystal conjugates are mixed together, it is possible to sort each type of nanoparticle using hybridization on a defined micrometer -size surface containing the complementary oligonucleotide. Detection of sorting requires only a single excitation source and an epifluorescence microscope. The possibility of directing fluorescent nanocrystals towards specific biological targets and detecting them, combined with their superior photo-stability compared to organic dyes, opens the way to improved biolabeling experiments, such as gene mapping on a nanometer scale or multicolor microarray analysis.

  20. Precipitation of hydroxyapatite on electrospun polycaprolactone/aloe vera/silk fibroin nanofibrous scaffolds for bone tissue engineering.

    Science.gov (United States)

    Shanmugavel, Suganya; Reddy, Venugopal Jayarama; Ramakrishna, Seeram; Lakshmi, B S; Dev, Vr Giri

    2014-07-01

    Advances in electrospun nanofibres with bioactive materials have enhanced the scope of fabricating biomimetic scaffolds for tissue engineering. The present research focuses on fabrication of polycaprolactone/aloe vera/silk fibroin nanofibrous scaffolds by electrospinning followed by hydroxyapatite deposition by calcium-phosphate dipping method for bone tissue engineering. Morphology, composition, hydrophilicity and mechanical properties of polycaprolactone/aloe vera/silk fibroin-hydroxyapatite nanofibrous scaffolds along with controls polycaprolactone and polycaprolactone/aloe vera/silk fibroin nanofibrous scaffolds were examined by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, contact angle and tensile tests, respectively. Adipose-derived stem cells cultured on polycaprolactone/aloe vera/silk fibroin-hydroxyapatite nanofibrous scaffolds displayed highest cell proliferation, increased osteogenic markers expression (alkaline phosphatase and osteocalcin), osteogenic differentiation and increased mineralization in comparison with polycaprolactone control. The obtained results indicate that polycaprolactone/aloe vera/silk fibroin-hydroxyapatite nanofibrous scaffolds have appropriate physico-chemical and biological properties to be used as biomimetic scaffolds for bone tissue regeneration. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  1. Hydroxyapatite coatings for biomedical applications

    CERN Document Server

    Zhang, Sam

    2013-01-01

    Hydroxyapatite coatings are of great importance in the biological and biomedical coatings fields, especially in the current era of nanotechnology and bioapplications. With a bonelike structure that promotes osseointegration, hydroxyapatite coating can be applied to otherwise bioinactive implants to make their surface bioactive, thus achieving faster healing and recovery. In addition to applications in orthopedic and dental implants, this coating can also be used in drug delivery. Hydroxyapatite Coatings for Biomedical Applications explores developments in the processing and property characteri

  2. Synthesis of Ag{sub 2}S nanorods by biomimetic method in the lysozyme matrix

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Dezhi, E-mail: dezhiqin@163.com; Zhang, Li; He, Guoxu; Zhang, Qiuxia

    2013-09-01

    Graphical abstract: - Highlights: • Firstly, Ag{sub 2}S nanorods were synthesized by biomimetic method in the lysozyme solutions. • The study of the interaction between Ag{sup +} and the lysozyme. • Discussion of possible formation mechanism of Ag{sub 2}S nanorods. • The synthesis process of lyso-conjugated Ag{sub 2}S nanocrystals is facile, effective and environment friendly. - Abstract: Ag{sub 2}S nanorods were successfully synthesized by biomimetic route in the lysozyme solution at physiological temperature and atmospheric pressure. The transmission electron microscopy (TEM) images revealed that the prepared nanorods are uniform and monodisperse with homogeneous size about 50 nm in diameter and 150 nm in length. The optical property of Ag{sub 2}S nanocrystals was studied by the ultraviolet–visible (UV–vis) and photoluminescence (PL) spectroscopy, the results show that the products exhibit well-defined emission at 471 nm and 496 nm excited by 292 nm. The interaction of Ag{sup +}/Ag{sub 2}S with the lysozyme was investigated through Fourier transform infrared (FT-IR) spectroscopy, which shows that the cooperation effect of the lysozyme and Ag{sup +} could be responsible for the formation of as obtained Ag{sub 2}S nanorods.

  3. Ionic Colloidal Molding as a Biomimetic Scaffolding Strategy for Uniform Bone Tissue Regeneration.

    Science.gov (United States)

    Zhang, Jian; Jia, Jinpeng; Kim, Jimin P; Shen, Hong; Yang, Fei; Zhang, Qiang; Xu, Meng; Bi, Wenzhi; Wang, Xing; Yang, Jian; Wu, Decheng

    2017-05-01

    Inspired by the highly ordered nanostructure of bone, nanodopant composite biomaterials are gaining special attention for their ability to guide bone tissue regeneration through structural and biological cues. However, bone malformation in orthopedic surgery is a lingering issue, partly due to the high surface energy of traditional nanoparticles contributing to aggregation and inhomogeneity. Recently, carboxyl-functionalized synthetic polymers have been shown to mimic the carboxyl-rich surface motifs of non-collagenous proteins in stabilizing hydroxyapatite and directing intrafibrillar mineralization in-vitro. Based on this biomimetic approach, it is herein demonstrated that carboxyl functionalization of poly(lactic-co-glycolic acid) can achieve great material homogeneity in nanocomposites. This ionic colloidal molding method stabilizes hydroxyapatite precursors to confer even nanodopant packing, improving therapeutic outcomes in bone repair by remarkably improving mechanical properties of nanocomposites and optimizing controlled drug release, resulting in better cell in-growth and osteogenic differentiation. Lastly, better controlled biomaterial degradation significantly improved osteointegration, translating to highly regular bone formation with minimal fibrous tissue and increased bone density in rabbit radial defect models. Ionic colloidal molding is a simple yet effective approach of achieving materials homogeneity and modulating crystal nucleation, serving as an excellent biomimetic scaffolding strategy to rebuild natural bone integrity. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Biomimetic membranes and methods of making biomimetic membranes

    Science.gov (United States)

    Rempe, Susan; Brinker, Jeffrey C.; Rogers, David Michael; Jiang, Ying-Bing; Yang, Shaorong

    2016-11-08

    The present disclosure is directed to biomimetic membranes and methods of manufacturing such membranes that include structural features that mimic the structures of cellular membrane channels and produce membrane designs capable of high selectivity and high permeability or adsorptivity. The membrane structure, material and chemistry can be selected to perform liquid separations, gas separation and capture, ion transport and adsorption for a variety of applications.

  5. New Hybrid Route to Biomimetic Synthesis

    National Research Council Canada - National Science Library

    Morse, Daniel

    2003-01-01

    To develop economical low-temperature routes to biomimetic synthesis of high-performance composite materials, with control of composition and structure based on the molecular mechanisms controlling...

  6. Bioinspired Bouligand cellulose nanocrystal composites: a review of mechanical properties

    Science.gov (United States)

    Natarajan, Bharath; Gilman, Jeffrey W.

    2017-12-01

    The twisted plywood, or Bouligand, structure is the most commonly observed microstructural motif in natural materials that possess high mechanical strength and toughness, such as that found in bone and the mantis shrimp dactyl club. These materials are isotropically toughened by a low volume fraction of soft, energy-dissipating polymer and by the Bouligand structure itself, through shear wave filtering and crack twisting, deflection and arrest. Cellulose nanocrystals (CNCs) are excellent candidates for the bottom-up fabrication of these structures, as they naturally self-assemble into `chiral nematic' films when cast from solutions and possess outstanding mechanical properties. In this article, we present a review of the fabrication techniques and the corresponding mechanical properties of Bouligand biomimetic CNC nanocomposites, while drawing comparison to the performance standards set by tough natural composite materials. This article is part of a discussion meeting issue `New horizons for cellulose nanotechnology'.

  7. Large scale biomimetic membrane arrays

    DEFF Research Database (Denmark)

    Hansen, Jesper Søndergaard; Perry, Mark; Vogel, Jörg

    2009-01-01

    To establish planar biomimetic membranes across large scale partition aperture arrays, we created a disposable single-use horizontal chamber design that supports combined optical-electrical measurements. Functional lipid bilayers could easily and efficiently be established across CO2 laser micro......-structured 8 x 8 aperture partition arrays with average aperture diameters of 301 +/- 5 mu m. We addressed the electro-physical properties of the lipid bilayers established across the micro-structured scaffold arrays by controllable reconstitution of biotechnological and physiological relevant membrane...... peptides and proteins. Next, we tested the scalability of the biomimetic membrane design by establishing lipid bilayers in rectangular 24 x 24 and hexagonal 24 x 27 aperture arrays, respectively. The results presented show that the design is suitable for further developments of sensitive biosensor assays...

  8. Biological and Biomimetic Comb Polyelectrolytes

    Directory of Open Access Journals (Sweden)

    Aristeidis Papagiannopoulos

    2010-05-01

    Full Text Available Some new phenomena involved in the physical properties of comb polyelectrolyte solutions are reviewed. Special emphasis is given to synthetic biomimetic materials, and the structures formed by these molecules are compared with those of naturally occurring glycoprotein and proteoglycan solutions. Developments in the determination of the structure and dynamics (viscoelasticity of comb polymers in solution are also covered. Specifically the appearance of multi-globular structures, helical instabilities, liquid crystalline phases, and the self-assembly of the materials to produce hierarchical comb morphologies is examined. Comb polyelectrolytes are surface active and a short review is made of some recent experiments in this area that relate to their morphology when suspended in solution. We hope to emphasize the wide variety of phenomena demonstrated by the vast range of naturally occurring comb polyelectrolytes and the challenges presented to synthetic chemists designing biomimetic materials.

  9. Cadmium immobilization by hydroxyapatite

    Directory of Open Access Journals (Sweden)

    Smičiklas Ivana D.

    2003-01-01

    Full Text Available The contamination of air, soil and water by cadmium is a great environmental problem. If cadmium occurs in nature in ionic form, soluble in water, it easily enters into the food chain. Hydroxyapatite (HAP, Ca-o(POAe(OH2 is a sparingly soluble salt and an excellent matrix for the removal of heavy metals from solutions. Considerable research attention has been paid to the bond between Cc/2+ ions and synthetic hydroxyapatite of known composition. The sorption mechanism is complex. The dominant process is ion exchange, but surface adsorption, surface complexation and coprecipitation can also contribute to the overall mechanism. The sorption capacity depends on the characteristics of hydroxyapatite itself and on the experimental conditions. Under optimum conditions a maximum capacity of 0.8 mol Cd2+/mol HAP can be achieved. HAP is a potential sorbent for the remediation of contaminated water and soil, for industrial waste treatment, and it is also referenced as a material that can be used as a barrier around waste depositories.

  10. Patterning nanocrystals using DNA

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Shara Carol [Univ. of California, Berkeley, CA (United States)

    2003-01-01

    One of the goals of nanotechnology is to enable programmed self-assembly of patterns made of various materials with nanometer-sized control. This dissertation describes the results of experiments templating arrangements of gold and semiconductor nanocrystals using 2'-deoxyribonucleic acid (DNA). Previously, simple DNA-templated linear arrangements of two and three nanocrystals structures have been made.[1] Here, we have sought to assemble larger and more complex nanostructures. Gold-DNA conjugates with 50 to 100 bases self-assembled into planned arrangements using strands of DNA containing complementary base sequences. We used two methods to increase the complexity of the arrangements: using branched synthetic doublers within the DNA covalent backbone to create discrete nanocrystal groupings, and incorporating the nanocrystals into a previously developed DNA lattice structure [2][3] that self-assembles from tiles made of DNA double-crossover molecules to create ordered nanoparticle arrays. In the first project, the introduction of a covalently-branched synthetic doubler reagent into the backbone of DNA strands created a branched DNA ''trimer.'' This DNA trimer templated various structures that contained groupings of three and four gold nanoparticles, giving promising, but inconclusive transmission electron microscopy (TEM) results. Due to the presence of a variety of possible structures in the reaction mixtures, and due to the difficulty of isolating the desired structures, the TEM and gel electrophoresis results for larger structures having four particles, and for structures containing both 5 and 10 nm gold nanoparticles were inconclusive. Better results may come from using optical detection methods, or from improved sample preparation. In the second project, we worked toward making two-dimensional ordered arrays of nanocrystals. We replicated and improved upon previous results for making DNA lattices, increasing the size of the lattices

  11. Magnetic hydroxyapatite nanoworms for magnetic resonance diagnosis of acute hepatic injury

    Science.gov (United States)

    Xu, Yun-Jun; Dong, Liang; Lu, Yang; Zhang, Le-Cheng; An, Duo; Gao, Huai-Ling; Yang, Dong-Mei; Hu, Wen; Sui, Cong; Xu, Wei-Ping; Yu, Shu-Hong

    2016-01-01

    Inorganic non-metallic biomaterials, including the silicon frustule of a unicellular diatom, the carbonate shell of a mollusk and the calcium skeleton of the vertebrate, which are the main constituent part of an organism, serve as the supportive and protective components of soft tissue. Among them, hydroxyapatite, which primarily makes up the enamel and bone, is widely used in tissue engineering. Recently, the inorganic nonmetallic biomaterials, especially the applications of hydroxyapatites have attracted great attention. Herein, we report a novel synthesis method of magnetic functionalized hydroxyapatite nanocomposites. By simply tuning the ratios of reactants, a series of hydroxyapatite-Fe3O4 worm-shaped nanocomposites (HAP-ION nanoworms) are obtained. In addition, layer-by-layer surface modifications with chitosan (CH) and sodium alginate (SA) were employed to improve the solubility and biocompatibility, and low cytotoxicity and no hemolysis were observed. With the increase of iron oxide nanocrystals, the magnetic properties of the magnetic assembled nanoworms were enhanced, which resulted in better performance of magnetic resonance (MR) imaging. Owing to the intravenous injection of HAP-ION nanoworms, the contrast to noise ratio (CNR) of hepatic MR imaging in vivo was enhanced obviously, which should be beneficial for hepatic injury grading and further therapeutic treatment.Inorganic non-metallic biomaterials, including the silicon frustule of a unicellular diatom, the carbonate shell of a mollusk and the calcium skeleton of the vertebrate, which are the main constituent part of an organism, serve as the supportive and protective components of soft tissue. Among them, hydroxyapatite, which primarily makes up the enamel and bone, is widely used in tissue engineering. Recently, the inorganic nonmetallic biomaterials, especially the applications of hydroxyapatites have attracted great attention. Herein, we report a novel synthesis method of magnetic

  12. Photoemission studies of semiconductor nanocrystals

    International Nuclear Information System (INIS)

    Hamad, K.S.; Roth, R.; Alivisatos, A.P.

    1997-01-01

    Semiconductor nanocrystals have been the focus of much attention in the last ten years due predominantly to their size dependent optical properties. Namely, the band gap of nanocrystals exhibits a shift to higher energy with decreasing size due to quantum confinement effects. Research in this field has employed primarily optical techniques to study nanocrystals, and in this respect this system has been investigated extensively. In addition, one is able to synthesize monodisperse, crystalline particles of CdS, CdSe, Si, InP, InAs, as well as CdS/HgS/CdS and CdSe/CdS composites. However, optical spectroscopies have proven ambiguous in determining the degree to which electronic excitations are interior or surface admixtures or giving a complete picture of the density of states. Photoemission is a useful technique for understanding the electronic structure of nanocrystals and the effects of quantum confinement, chemical environments of the nanocrystals, and surface coverages. Of particular interest to the authors is the surface composition and structure of these particles, for they have found that much of the behavior of nanocrystals is governed by their surface. Previously, the authors had performed x-ray photoelectron spectroscopy (XPS) on CdSe nanocrystals. XPS has proven to be a powerful tool in that it allows one to determine the composition of the nanocrystal surface

  13. Method of synthesizing pyrite nanocrystals

    Science.gov (United States)

    Wadia, Cyrus; Wu, Yue

    2013-04-23

    A method of synthesizing pyrite nanocrystals is disclosed which in one embodiment includes forming a solution of iron (III) diethyl dithiophosphate and tetra-alkyl-ammonium halide in water. The solution is heated under pressure. Pyrite nanocrystal particles are then recovered from the solution.

  14. Nanocrystal/sol-gel nanocomposites

    Science.gov (United States)

    Petruska, Melissa A [Los Alamos, NM; Klimov, Victor L [Los Alamos, NM

    2007-06-05

    The present invention is directed to solid composites including colloidal nanocrystals within a sol-gel host or matrix and to processes of forming such solid composites. The present invention is further directed to alcohol soluble colloidal nanocrystals useful in formation of sol-gel based solid composites.

  15. Development and characterization of a novel porous small intestine submucosa-hydroxyapatite scaffold for bone regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Castilla Bolaños, Maria Alejandra, E-mail: ma.castilla964@uniandes.edu.co; Buttigieg, Josef; Briceño Triana, Juan Carlos

    2017-03-01

    The fabricated small intestine submucosa (SIS) – hydroxyapatite (HAp) sponges can act as biomimetic scaffolds to be utilized in tissue engineering and regeneration. Here we developed SIS-HAp sponges and investigated their mechanical, physical and chemical characteristics using scanning electron microscopy, Fourier transformed infrared spectroscopy, uniaxial compression, porosity, and swelling testing techniques. The results demonstrated mechanical properties superior to comparable bone substitutes fabricated with similar methods. SIS-HAp scaffolds possess an interconnected macroporosity, similar to that of trabecular bone, hence presenting a novel biomaterial that may serve as a superior bone substitute and tissue scaffold. - Highlights: • Small intestine submucosa (SIS) – hydroxyapatite (HAp) scaffolds were developed. • SIS-HAp scaffolds possess a trabecular bone-like structure. • FTIR indicated a molecular interaction between the organic groups of SIS and HAp. • SIS-HAp sponges presented a superior Young modulus to comparable bone substitutes.

  16. Development and characterization of a novel porous small intestine submucosa-hydroxyapatite scaffold for bone regeneration

    International Nuclear Information System (INIS)

    Castilla Bolaños, Maria Alejandra; Buttigieg, Josef; Briceño Triana, Juan Carlos

    2017-01-01

    The fabricated small intestine submucosa (SIS) – hydroxyapatite (HAp) sponges can act as biomimetic scaffolds to be utilized in tissue engineering and regeneration. Here we developed SIS-HAp sponges and investigated their mechanical, physical and chemical characteristics using scanning electron microscopy, Fourier transformed infrared spectroscopy, uniaxial compression, porosity, and swelling testing techniques. The results demonstrated mechanical properties superior to comparable bone substitutes fabricated with similar methods. SIS-HAp scaffolds possess an interconnected macroporosity, similar to that of trabecular bone, hence presenting a novel biomaterial that may serve as a superior bone substitute and tissue scaffold. - Highlights: • Small intestine submucosa (SIS) – hydroxyapatite (HAp) scaffolds were developed. • SIS-HAp scaffolds possess a trabecular bone-like structure. • FTIR indicated a molecular interaction between the organic groups of SIS and HAp. • SIS-HAp sponges presented a superior Young modulus to comparable bone substitutes.

  17. BIOMIMETIC STRATEGIES IN ORGANIC SYNTHESIS. TERPENES

    Directory of Open Access Journals (Sweden)

    V. Kulcitki

    2012-12-01

    Full Text Available The current paper represents an outline of the selected contributions to the biomimetic procedures and approaches for the synthesis of terpenes with complex structure and diverse functionalisation pattern. These include homologation strategies, cyclisations, rearrangements, as well as biomimetic remote functionalisations.

  18. Sensing in nature: using biomimetics for design of sensors

    DEFF Research Database (Denmark)

    Lenau, Torben Anker; Cheong, Hyunmin; Shu, Li

    2010-01-01

    The paper illustrates how biomimetics can be applied in sensor design. Biomimetics is an engineering discipline that uses nature as an inspiration source for generating ideas for how to solve engineering problems. Using biomimetics involves a search for relevant cases, a proper analysis...... of biomimetic studies of sense organs in animals....

  19. Biomimetics in drug delivery systems: A critical review.

    Science.gov (United States)

    Sheikhpour, Mojgan; Barani, Leila; Kasaeian, Alibakhsh

    2017-05-10

    Today, the advanced drug delivery systems have been focused on targeted drug delivery fields. The novel drug delivery is involved with the improvement of the capacity of drug loading in drug carriers, cellular uptake of drug carriers, and the sustained release of drugs within target cells. In this review, six groups of therapeutic drug carriers including biomimetic hydrogels, biomimetic micelles, biomimetic liposomes, biomimetic dendrimers, biomimetic polymeric carriers and biomimetic nanostructures, are studied. The subject takes advantage of the biomimetic methods of productions or the biomimetic techniques for the surface modifications, similar to what accrues in natural cells. Moreover, the effects of these biomimetic approaches for promoting the drug efficiency in targeted drug delivery are visible. The study demonstrates that the fabrication of biomimetic nanocomposite drug carriers could noticeably promote the efficiency of drugs in targeted drug delivery systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Hydroxyapatite coating on the titanium substrate modulated by a recombinant collagen-like protein

    International Nuclear Information System (INIS)

    Pan Mingli; Kong Xiangdong; Cai Yurong; Yao Juming

    2011-01-01

    Research highlights: → Hydroxyapatite was deposited on alkali-heat treated Ti substrate by immersing in 1.5 x SBF solution containing the recombinant collagen-like protein. → The recombinant collagen-like protein accelerated the preferential nucleation and growth of hydroxyapatite along c axis on the Ti substrate. → Hydroxyapatite-collagen composite on the Ti substrate promoted the attachment, subsequently proliferation and differentiation of MG-63 cells. - Abstract: Plenty of techniques have been developed to modify the surface character of titanium (Ti) and its alloys in order to realize their biological bond to natural bone. In this work, a biomimetic process was employed to form a hydroxyapatite (HAp) coating on the alkali-heat treated Ti substrate in 1.5 times simulated body fluid (1.5 x SBF) with the addition of a recombinant collagen-like protein. The coating was characterized using SEM-EDX, FESEM, and XRD. Results showed that the recombinant collagen-like protein could accelerate the preferential nucleation and directional growth along c axis of HAp on the pretreated Ti substrates. The investigation of in vitro cell cultivation showed that the existence of recombinant collagen-like protein in coating could improve the initial cell adhesion, proliferation and differentiation of MG-63 cells, which implied the materials possessed excellent biocompatibility and had a wide potential in biomedical application.

  1. Hydroxyapatite coating on the titanium substrate modulated by a recombinant collagen-like protein

    Energy Technology Data Exchange (ETDEWEB)

    Pan Mingli [Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textile, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Kong Xiangdong [College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Cai Yurong [Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textile, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Yao Juming, E-mail: yaoj@zstu.edu.cn [Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textile, Zhejiang Sci-Tech University, Hangzhou 310018 (China)

    2011-04-15

    Research highlights: {yields} Hydroxyapatite was deposited on alkali-heat treated Ti substrate by immersing in 1.5 x SBF solution containing the recombinant collagen-like protein. {yields} The recombinant collagen-like protein accelerated the preferential nucleation and growth of hydroxyapatite along c axis on the Ti substrate. {yields} Hydroxyapatite-collagen composite on the Ti substrate promoted the attachment, subsequently proliferation and differentiation of MG-63 cells. - Abstract: Plenty of techniques have been developed to modify the surface character of titanium (Ti) and its alloys in order to realize their biological bond to natural bone. In this work, a biomimetic process was employed to form a hydroxyapatite (HAp) coating on the alkali-heat treated Ti substrate in 1.5 times simulated body fluid (1.5 x SBF) with the addition of a recombinant collagen-like protein. The coating was characterized using SEM-EDX, FESEM, and XRD. Results showed that the recombinant collagen-like protein could accelerate the preferential nucleation and directional growth along c axis of HAp on the pretreated Ti substrates. The investigation of in vitro cell cultivation showed that the existence of recombinant collagen-like protein in coating could improve the initial cell adhesion, proliferation and differentiation of MG-63 cells, which implied the materials possessed excellent biocompatibility and had a wide potential in biomedical application.

  2. Carbonate hydroxyapatite and silicon-substituted carbonate hydroxyapatite

    DEFF Research Database (Denmark)

    Bang, L T; Long, B D; Othman, R

    2014-01-01

    The present study investigates the chemical composition, solubility, and physical and mechanical properties of carbonate hydroxyapatite (CO3Ap) and silicon-substituted carbonate hydroxyapatite (Si-CO3Ap) which have been prepared by a simple precipitation method. X-ray diffraction (XRD), Fourier......(3-)) site and also entered simultaneously into the hydroxyapatite structure. The Si-substituted CO3Ap reduced the powder crystallinity and promoted ion release which resulted in a better solubility compared to that of Si-free CO3Ap. The mean particle size of Si-CO3Ap was much finer than that of CO3Ap...

  3. Biomimetic calcium phosphate coating of additively manufactured porous CoCr implants

    Energy Technology Data Exchange (ETDEWEB)

    Lindahl, Carl [BIOMATCELL Vinn Excellence Center of Biomaterials and Cell Therapy, Gothenburg (Sweden); Department of Engineering Sciences, Ångstrom Laboratory, Uppsala University, Uppsala (Sweden); Xia, Wei, E-mail: wei.xia@angstrom.uu.se [BIOMATCELL Vinn Excellence Center of Biomaterials and Cell Therapy, Gothenburg (Sweden); Department of Engineering Sciences, Ångstrom Laboratory, Uppsala University, Uppsala (Sweden); Engqvist, Håkan [BIOMATCELL Vinn Excellence Center of Biomaterials and Cell Therapy, Gothenburg (Sweden); Department of Engineering Sciences, Ångstrom Laboratory, Uppsala University, Uppsala (Sweden); Snis, Anders [BIOMATCELL Vinn Excellence Center of Biomaterials and Cell Therapy, Gothenburg (Sweden); Arcam AB, Krokslätts Fabriker 27 A, SE-431 37 Mölndal (Sweden); Lausmaa, Jukka [BIOMATCELL Vinn Excellence Center of Biomaterials and Cell Therapy, Gothenburg (Sweden); Department of Chemistry, Materials and Surfaces, SP Technical Research Institute of Sweden, Borås (Sweden); Palmquist, Anders [BIOMATCELL Vinn Excellence Center of Biomaterials and Cell Therapy, Gothenburg (Sweden); Department of Biomaterials, Sahlgrenska Academy at the University of Gothenburg, Gothenburg (Sweden)

    2015-10-30

    Highlights: • A route for coating complex shaped electron beam melted implants is presented. • Biomimetic HA coatings were deposited on CoCr alloys using a solution method. • Deposited biomimetic coating was partially crystalline, slightly calcium deficient. • Coating morphology was plate-like with crystallites forming roundish flowers. • Present coating procedure could be useful for porous implants made by EBM. - Abstract: The aim of this work was to study the feasibility to use a biomimetic method to prepare biomimetic hydroxyapatite (HA) coatings on CoCr substrates with short soaking times and to characterize the properties of such coatings. A second objective was to investigate if the coatings could be applied to porous CoCr implants manufactured by electron beam melting (EBM). The coating was prepared by immersing the pretreated CoCr substrates and EBM implants into the phosphate-buffered solution with Ca{sup 2+} in sealed plastic bottles, kept at 60 °C for 3 days. The formed coating was partially crystalline, slightly calcium deficient and composed of plate-like crystallites forming roundish flowers in the size range of 300–500 nm. Cross-section imaging showed a thickness of 300–500 nm. In addition, dissolution tests in Tris–HCl up to 28 days showed that a substantial amount of the coating had dissolved, however, undergoing only minor morphological changes. A uniform coating was formed within the porous network of the additive manufactured implants having similar thickness and morphology as for the flat samples. In conclusion, the present coating procedure allows coatings to be formed on CoCr and could be used for complex shaped, porous implants made by additive manufacturing.

  4. Biomimetic calcium phosphate coating of additively manufactured porous CoCr implants

    International Nuclear Information System (INIS)

    Lindahl, Carl; Xia, Wei; Engqvist, Håkan; Snis, Anders; Lausmaa, Jukka; Palmquist, Anders

    2015-01-01

    Highlights: • A route for coating complex shaped electron beam melted implants is presented. • Biomimetic HA coatings were deposited on CoCr alloys using a solution method. • Deposited biomimetic coating was partially crystalline, slightly calcium deficient. • Coating morphology was plate-like with crystallites forming roundish flowers. • Present coating procedure could be useful for porous implants made by EBM. - Abstract: The aim of this work was to study the feasibility to use a biomimetic method to prepare biomimetic hydroxyapatite (HA) coatings on CoCr substrates with short soaking times and to characterize the properties of such coatings. A second objective was to investigate if the coatings could be applied to porous CoCr implants manufactured by electron beam melting (EBM). The coating was prepared by immersing the pretreated CoCr substrates and EBM implants into the phosphate-buffered solution with Ca"2"+ in sealed plastic bottles, kept at 60 °C for 3 days. The formed coating was partially crystalline, slightly calcium deficient and composed of plate-like crystallites forming roundish flowers in the size range of 300–500 nm. Cross-section imaging showed a thickness of 300–500 nm. In addition, dissolution tests in Tris–HCl up to 28 days showed that a substantial amount of the coating had dissolved, however, undergoing only minor morphological changes. A uniform coating was formed within the porous network of the additive manufactured implants having similar thickness and morphology as for the flat samples. In conclusion, the present coating procedure allows coatings to be formed on CoCr and could be used for complex shaped, porous implants made by additive manufacturing.

  5. Biomolecular Assembly of Gold Nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Micheel, Christine Marya [Univ. of California, Berkeley, CA (United States)

    2005-05-20

    Over the past ten years, methods have been developed to construct discrete nanostructures using nanocrystals and biomolecules. While these frequently consist of gold nanocrystals and DNA, semiconductor nanocrystals as well as antibodies and enzymes have also been used. One example of discrete nanostructures is dimers of gold nanocrystals linked together with complementary DNA. This type of nanostructure is also known as a nanocrystal molecule. Discrete nanostructures of this kind have a number of potential applications, from highly parallel self-assembly of electronics components and rapid read-out of DNA computations to biological imaging and a variety of bioassays. My research focused in three main areas. The first area, the refinement of electrophoresis as a purification and characterization method, included application of agarose gel electrophoresis to the purification of discrete gold nanocrystal/DNA conjugates and nanocrystal molecules, as well as development of a more detailed understanding of the hydrodynamic behavior of these materials in gels. The second area, the development of methods for quantitative analysis of transmission electron microscope data, used computer programs written to find pair correlations as well as higher order correlations. With these programs, it is possible to reliably locate and measure nanocrystal molecules in TEM images. The final area of research explored the use of DNA ligase in the formation of nanocrystal molecules. Synthesis of dimers of gold particles linked with a single strand of DNA possible through the use of DNA ligase opens the possibility for amplification of nanostructures in a manner similar to polymerase chain reaction. These three areas are discussed in the context of the work in the Alivisatos group, as well as the field as a whole.

  6. Methane hydroxylation: a biomimetic approach

    International Nuclear Information System (INIS)

    Shilov, Aleksandr E; Shteinman, Al'bert A

    2012-01-01

    The review addresses direct methane oxidation — an important fundamental problem, which has attracted much attention of researchers in recent years. Analysis of the available results on biomimetic and bio-inspired methane oxygenation has demonstrated that assimilating of the experience of Nature on oxidation of methane and other alkanes significantly enriches the arsenal of chemistry and can radically change the character of the entire chemical production, as well as enables the solution of many material, energetic and environmental problems. The bibliography includes 310 references.

  7. Synthesis and Doping of Silicon Nanocrystals for Versatile Nanocrystal Inks

    Science.gov (United States)

    Kramer, Nicolaas Johannes

    The impact of nanotechnology on our society is getting larger every year. Electronics are becoming smaller and more powerful, the "Internet of Things" is all around us, and data generation is increasing exponentially. None of this would have been possible without the developments in nanotechnology. Crystalline semiconductor nanoparticles (nanocrystals) are one of the latest developments in the field of nanotechnology. This thesis addresses three important challenges for the transition of silicon nanocrystals from the lab bench to the marketplace: A better understanding of the nanocrystal synthesis was obtained, the electronic properties of the nanocrystals were characterized and tuned, and novel silicon nanocrystal inks were formed and applied using simple coating technologies. Plasma synthesis of nanocrystals has numerous advantages over traditional solution-based synthesis methods. While the formation of nanoparticles in low pressure nonthermal plasmas is well known, the heating mechanism leading to their crystallization is poorly understood. A combination of comprehensive plasma characterization with a nanoparticle heating model presented here reveals the underlying plasma physics leading to crystallization. The model predicts that the nanoparticles reach temperatures as high as 900 K in the plasma as a result of heating reactions on the nanoparticle surface. These temperatures are well above the gas temperature and sufficient for complete nanoparticle crystallization. Moving the field of plasma nanoparticle synthesis to atmospheric pressures is important for lowering its cost and making the process attractive for industrial applications. The heating and charging model for silicon nanoparticles was adapted in Chapter 3 to study plasmas maintained over a wide range of pressures (10 -- 105 Pa). The model considers three collisionality regimes and determines the dominant contribution of each regime under various plasma conditions. Strong nanoparticle cooling at

  8. Biomimetic vibrissal sensing for robots.

    Science.gov (United States)

    Pearson, Martin J; Mitchinson, Ben; Sullivan, J Charles; Pipe, Anthony G; Prescott, Tony J

    2011-11-12

    Active vibrissal touch can be used to replace or to supplement sensory systems such as computer vision and, therefore, improve the sensory capacity of mobile robots. This paper describes how arrays of whisker-like touch sensors have been incorporated onto mobile robot platforms taking inspiration from biology for their morphology and control. There were two motivations for this work: first, to build a physical platform on which to model, and therefore test, recent neuroethological hypotheses about vibrissal touch; second, to exploit the control strategies and morphology observed in the biological analogue to maximize the quality and quantity of tactile sensory information derived from the artificial whisker array. We describe the design of a new whiskered robot, Shrewbot, endowed with a biomimetic array of individually controlled whiskers and a neuroethologically inspired whisking pattern generation mechanism. We then present results showing how the morphology of the whisker array shapes the sensory surface surrounding the robot's head, and demonstrate the impact of active touch control on the sensory information that can be acquired by the robot. We show that adopting bio-inspired, low latency motor control of the rhythmic motion of the whiskers in response to contact-induced stimuli usefully constrains the sensory range, while also maximizing the number of whisker contacts. The robot experiments also demonstrate that the sensory consequences of active touch control can be usefully investigated in biomimetic robots.

  9. Challenges in Commercializing Biomimetic Membranes.

    Science.gov (United States)

    Perry, Mark; Madsen, Steen Ulrik; Jørgensen, Tine; Braekevelt, Sylvie; Lauritzen, Karsten; Hélix-Nielsen, Claus

    2015-11-05

    The discovery of selective water channel proteins-aquaporins-has prompted growing interest in using these proteins, as the building blocks for designing new types of membranes. However, as with any other new and potentially disruptive technology, barriers for successful market entry exist. One category includes customer-related barriers, which can be influenced to some extent. Another category includes market-technical-related barriers, which can be very difficult to overcome by an organization/company aiming at successfully introducing their innovation on the market-in particular if both the organization and the technology are at early stages. Often, one faces barriers from both these categories at the same time, which makes it necessary to gain insight of the particular market when introducing a new innovative product. In this review we present the basic concepts and discuss some of these barriers and challenges associated with introducing biomimetic aquaporin membranes. These include technical issues in membrane production and product testing. Then we discuss possible business models for introducing new technologies in general, followed by a presentation of beach-head market segments relevant for biomimetic aquaporin membranes.

  10. Challenges in Commercializing Biomimetic Membranes

    Directory of Open Access Journals (Sweden)

    Mark Perry

    2015-11-01

    Full Text Available The discovery of selective water channel proteins—aquaporins—has prompted growing interest in using these proteins, as the building blocks for designing new types of membranes. However, as with any other new and potentially disruptive technology, barriers for successful market entry exist. One category includes customer-related barriers, which can be influenced to some extent. Another category includes market-technical-related barriers, which can be very difficult to overcome by an organization/company aiming at successfully introducing their innovation on the market—in particular if both the organization and the technology are at early stages. Often, one faces barriers from both these categories at the same time, which makes it necessary to gain insight of the particular market when introducing a new innovative product. In this review we present the basic concepts and discuss some of these barriers and challenges associated with introducing biomimetic aquaporin membranes. These include technical issues in membrane production and product testing. Then we discuss possible business models for introducing new technologies in general, followed by a presentation of beach-head market segments relevant for biomimetic aquaporin membranes.

  11. Preferential Alignment of Hydroxyapatite Crystallites in Nanocomposites with Chemically Disintegrated Silk Fibroin

    International Nuclear Information System (INIS)

    Nemoto, Rei; Wang Li; Ikoma, Toshiyuki; Tanaka, Junzo; Senna, Mamoru

    2004-01-01

    Hydroxyapatite (HAp) nanocrystals were prepared at room temperature by a coprecipitation method from Ca(OH) 2 and H 3 PO 4 , in the presence of chemically disintegrated silk fibroin (SF). Adsorbed amounts of cations on SF and crystallinity of HAp in the composite were increased by the chemical disintegration of SF higher order structure. Preferential alignment of c-axis of HAp crystallites along the longitudinal direction of ca. 150nm SF fibril was observed. These changes due to disintegration of SF were discussed in terms of the chemical interaction between HAp and SF. The resulted composite with preferential alignment of HAp nanocrystals is a good candidate as a starting material for bone substitutes

  12. Optimizing colloidal nanocrystals for applications

    International Nuclear Information System (INIS)

    Sytnyk, M.

    2015-01-01

    In the scientific literature colloidal nanocrystals are presented as promising materials for multiple applications, in areas covering optoelectronics, photovoltaics, spintronics, catalysis, and bio-medicine. On the marked are, however, only a very limited number of examples found, indeed implementing colloidal nanocrystals. Thus the scope of this thesis was to modify nanocrystals and to tune their properties to fulfill specific demands. While some modifications could be achieved by post synthetic treatments, one key problem of colloidal nanocrystals, hampering there widespread application is the toxicity of their constituents. To develop nanocrystals from non-toxic materials has been a major goal of this thesis as well. Roughly, the results in this thesis could be subdivided into three parts: (i) the development of ion exchange methods to tailor the properties of metallic and metal-oxide based nanocrystal heterostructures, (ii), the synthesis of semiconductor nanocrystals from non-toxic materials, and (iii) the characterization of the nanocrystals by measurements of their morphology, chemical composition, magnetic-, optical-, and electronic properties. In detail, the thesis is subdivided into an introductory chapter, 4 chapters reporting on scientific results, a chapter reporting the used methods, and the conclusions. The 4 chapters devoted to the scientific results correspond to manuscripts, which are either currently in preparation, or have been published in highly ranked scientific journals such as NanoLetters (chapter 2), ACS Nano (chapter 4), or JACS (chapter 5). Thus, these chapters provide also an extra introduction and conclusion section, as well as separate reference lists. Chapter 2 describes a cation exchange process which is used to tune and improve the magnetic properties of different iron-oxide based colloidal nanocrystal-heterostructures. The superparamagnetic blocking temperature, magnetic remanence, and coercivity is tuned by replacing Fe2+ by Co2

  13. MRI of orbital hydroxyapatite implants

    International Nuclear Information System (INIS)

    Flanders, A.E.; De Potter P.; Rao, V.M.; Tom, B.M.; Shields, C.L.; Shields, J.A.

    1996-01-01

    Our aim was to use MRI for the postsurgical assessment of a new form of integrated orbital implant composed of a porous calcium phosphate hydroxyapatite substrate. We studied ten patients 24-74 years of age who underwent enucleation and implantation of a hydroxyapatite ball; 5-13 months after surgery, each patient was examined by spin-echo MRI, with fat suppression and gadolinium enhancement. Fibrovascular ingrowth was demonstrated in all ten patients as areas of enhancement at the periphery of the hydroxyapatite sphere that extended to the center to a variable degree. The radiologist should aware of the MRI appearances of the coralline hydroxyapatite orbital implant since it is now widely used following enucleation. MRI is a useful means to determine successful incorporation of the substrate into the orbital tissues. The normal pattern of contrast enhancement should not be mistaken for recurrent tumor or infection. (orig.)

  14. Synthesis of nanocrystalline fluorinated hydroxyapatite

    Indian Academy of Sciences (India)

    Fluorinated hydroxyapatite; nanocrystalline; microwave synthesis; dissolution. ... HA by the presence of other ions such as carbonate, magnesium, fluoride, etc. ... Fourier transform infrared spectroscopy (FT–IR) and laser Raman spectroscopy.

  15. Targeted Delivery of Hyaluronan-Immobilized Magnetic Ceramic Nanocrystals.

    Science.gov (United States)

    Wu, Hsi-Chin; Wang, Tzu-Wei; Hsieh, Shun-Yu; Sun, Jui-Sheng; Kang, Pei-Leun

    2016-01-01

    Effective cancer therapy relies on delivering the therapeutic agent precisely to the target site to improve the treatment outcome and to minimize side effects. Although surgery, chemotherapy, and radiotherapy are the standard methods commonly used in clinics, hyperthermia has been developed as a new and promising strategy for cancer therapy. In this study, magnetic bioceramic hydroxyapatite (mHAP) nanocrystals have been developed as heat mediator for intracellular hyperthermia. Hyaluronic acid (HA) modified mHAP nanocrystals are synthesized by a wet chemical precipitation process to achieve active targeting. The results demonstrate that the HA targeting moiety conjugated by a poly(ethylene glycol) (PEG) spacer arm is successfully immobilized on the surface of mHAP. The HA-modified mHAP possesses relatively good biocompatibility, an adequate biodegradation rate and superparamagnetic properties. The HA-modified mHAP could be localized and internalized into HA receptor-overexpressed malignant cells (e.g., MDA-MB-231 cell) and used as the heat generating agent for intracellular hyperthermia. The results from this study indicate that biocompatible HA-modified mHAP shows promise as a novel heat mediator and a specific targeting nanoagent for intracellular hyperthermia cancer therapy.

  16. Biomimetics: determining engineering opportunities from nature

    Science.gov (United States)

    Fish, Frank E.

    2009-08-01

    The biomimetic approach seeks to incorporate designs based on biological organisms into engineered technologies. Biomimetics can be used to engineer machines that emulate the performance of organisms, particularly in instances where the organism's performance exceeds current mechanical technology or provides new directions to solve existing problems. For biologists, an adaptationist program has allowed for the identification of novel features of organisms based on engineering principles; whereas for engineers, identification of such novel features is necessary to exploit them for biomimetic development. Adaptations (leading edge tubercles to passively modify flow and high efficiency oscillatory propulsive systems) from marine animals demonstrate potential utility in the development of biomimetic products. Nature retains a store of untouched knowledge, which would be beneficial in advancing technology.

  17. Biomimetic membranes for sensor and separation applications

    CERN Document Server

    2012-01-01

    This book addresses the possibilities and challenges in mimicking biological membranes and creating membrane-based sensor and separation devices. It covers recent advances in developing biomimetic membranes for technological applications with a focus on the use of integral membrane protein mediated transport. It describes the fundamentals of biosensing as well as separation and shows how the two processes work together in biological systems. The book provides an overview of the current state of the art, points to areas that need further investigation and anticipates future directions in the field. Biomimetics is a truly cross-disciplinary approach and this is exemplified by the challenges in mimicking osmotic processes as they occur in nature using aquaporin protein water channels as central building blocks. In the development of a biomimetic sensor/separation technology, both channel and carrier proteins are important and examples of how these may be reconstituted and controlled in biomimetic membranes are ...

  18. Molecular motor assembly of a biomimetic system

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Active biological molecules and functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery, disease diagnosis and therapy, and new nanodevice construction.

  19. Biomimetic design method for innovation and sustainability

    CERN Document Server

    Helfman Cohen, Yael

    2017-01-01

    Presenting a novel biomimetic design method for transferring design solutions from nature to technology, this book focuses on structure-function patterns in nature and advanced modeling tools derived from TRIZ, the theory of inventive problem-solving. The book includes an extensive literature review on biomimicry as an engine of both innovation and sustainability, and discusses in detail the biomimetic design process, current biomimetic design methods and tools. The structural biomimetic design method for innovation and sustainability put forward in this text encompasses (1) the research method and rationale used to develop and validate this new design method; (2) the suggested design algorithm and tools including the Findstructure database, structure-function patterns and ideality patterns; and (3) analyses of four case studies describing how to use the proposed method. This book offers an essential resource for designers who wish to use nature as a source of inspiration and knowledge, innovators and sustain...

  20. Photoexcited iron porphyrin as biomimetic catalysts

    International Nuclear Information System (INIS)

    Bartocci, C.; Maldotti, A.; Varani, G.; Consiglio Nazionale delle Ricerche, Ferrara

    1996-01-01

    Photoexcited iron porphyrins can be of some interest in both fine and industrial chemistry in view of the preparation of new efficient biomimetic catalysts, working with high selectivity under mild temperature and pressure

  1. Cellulose nanocrystal submonolayers by spin coating

    NARCIS (Netherlands)

    Kontturi, E.J.; Johansson, L.S.; Kontturi, K.S.; Ahonen, P.; Thune, P.C.; Laine, J.

    2007-01-01

    Dilute concentrations of cellulose nanocrystal solutions were spin coated onto different substrates to investigate the effect of the substrate on the nanocrystal submonolayers. Three substrates were probed: silica, titania, and amorphous cellulose. According to atomic force microscopy (AFM) images,

  2. Biomimetic and Bioinspired Synthesis of Nanomaterials/Nanostructures.

    Science.gov (United States)

    Zan, Guangtao; Wu, Qingsheng

    2016-03-16

    In recent years, due to its unparalleled advantages, the biomimetic and bioinspired synthesis of nanomaterials/nanostructures has drawn increasing interest and attention. Generally, biomimetic synthesis can be conducted either by mimicking the functions of natural materials/structures or by mimicking the biological processes that organisms employ to produce substances or materials. Biomimetic synthesis is therefore divided here into "functional biomimetic synthesis" and "process biomimetic synthesis". Process biomimetic synthesis is the focus of this review. First, the above two terms are defined and their relationship is discussed. Next different levels of biological processes that can be used for process biomimetic synthesis are compiled. Then the current progress of process biomimetic synthesis is systematically summarized and reviewed from the following five perspectives: i) elementary biomimetic system via biomass templates, ii) high-level biomimetic system via soft/hard-combined films, iii) intelligent biomimetic systems via liquid membranes, iv) living-organism biomimetic systems, and v) macromolecular bioinspired systems. Moreover, for these five biomimetic systems, the synthesis procedures, basic principles, and relationships are discussed, and the challenges that are encountered and directions for further development are considered. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Challenges in commercializing biomimetic membranes

    DEFF Research Database (Denmark)

    Perry, Mark; Madsen, Steen Ulrik; Jørgensen, Tine Elkjær

    2015-01-01

    category includes customer-related barriers, which can be influenced to some extent. Another category includes market-technical-related barriers, which can be very difficult to overcome by an organization/company aiming at successfully introducing their innovation on the market—in particular if both...... the organization and the technology are at early stages. Often, one faces barriers from both these categories at the same time, which makes it necessary to gain insight of the particular market when introducing a new innovative product. In this review we present the basic concepts and discuss some...... of these barriers and challenges associated with introducing biomimetic aquaporin membranes. These include technical issues in membrane production and product testing. Then we discuss possible business models for introducing new technologies in general, followed by a presentation of beach-head market segments...

  4. Contact kinematics of biomimetic scales

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Ranajay; Ebrahimi, Hamid; Vaziri, Ashkan, E-mail: vaziri@coe.neu.edu [Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts 02115 (United States)

    2014-12-08

    Dermal scales, prevalent across biological groups, considerably boost survival by providing multifunctional advantages. Here, we investigate the nonlinear mechanical effects of biomimetic scale like attachments on the behavior of an elastic substrate brought about by the contact interaction of scales in pure bending using qualitative experiments, analytical models, and detailed finite element (FE) analysis. Our results reveal the existence of three distinct kinematic phases of operation spanning linear, nonlinear, and rigid behavior driven by kinematic interactions of scales. The response of the modified elastic beam strongly depends on the size and spatial overlap of rigid scales. The nonlinearity is perceptible even in relatively small strain regime and without invoking material level complexities of either the scales or the substrate.

  5. Formation of nano-hydroxyapatite crystal in situ in chitosan-pectin polyelectrolyte complex network

    International Nuclear Information System (INIS)

    Li Junjie; Zhu Dunwan; Yin Jianwei; Liu Yuxi; Yao Fanglian; Yao Kangde

    2010-01-01

    Hydroxyapatite (HA)/polysaccharide composites have been widely used in bone tissue engineering due to their chemical similarity to natural bone. Polymer matrix-mediated synthesis of nano-hydroxyapatite is one of the simplest models for biomimetic. In this article, the nano-hydroxyapatite/chitosan-pectin (nHCP) composites were prepared through in situ mineralization of hydroxyapatite in chitosan-pectin polyelectrolyte complex (PEC) network. The formation processes of nHCP were investigated by X-ray diffraction (XRD) analysis. The interactions between nHA crystal and chitosan-pectin PEC networks were studied using Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). The morphology and structure of nHA crystal were characterized by XRD and Transmission Electron Microscope (TEM). Results suggested that the interfacial interactions between nano-hydroxyapatite crystal and chitosan-pectin PEC network assist the site specific nucleation and growth of nHA nanoparticles. The nHA crystals grow along the c-axis. In this process, pH value is the main factor to control the nucleation and growth of nHA crystal in chitosan-pectin PEC networks, because both the interactions' strength between nHA crystal and chitosan-pectin and diffusion rate of inorganic ions depend on the pH value of the reaction system. Apart from the pH value, the chitosan/pectin ratio and [Ca 2+ ] also take important effects on the formation of nHA crystal. An effective way to control the size of nHA crystal is to adjust the content of pectin and [Ca 2+ ]. It is interesting that the Zeta potential of nHCP composites is about - 30 mV when the chitosan/pectin ratio ≤ 1:1, and the dispersion solution of nHCP composites has higher stability, which provides the possibility to prepare 3D porous scaffolds with nHCP for bone tissue engineering.

  6. Comparative facile methods for preparing graphene oxide-hydroxyapatite for bone tissue engineering.

    Science.gov (United States)

    Raucci, M G; Giugliano, D; Longo, A; Zeppetelli, S; Carotenuto, G; Ambrosio, L

    2017-08-01

    Motivated by the success of using graphene oxide (GO) as a nanofiller of composites, there is a drive to search for this new kind of carbon material as a bioactive component in ceramic materials. In the present study, biomineralized GO was prepared by two different approaches, represented by in situ sol-gel synthesis and biomimetic treatment. It was found that in the biocomposites obtained by the sol-gel approach, the spindle-like hydroxyapatite nanoparticles, with a diameter of ca. 5 ± 0.37 nm and a length of ca. 70 ± 2.5 nm, were presented randomly and strongly on the surface. The oxygen-containing functional groups, such as hydroxyl and carbonyl, present on the basal plane and edges of the GO sheets, play an important role in anchoring calcium ions, as demonstrated by FT-IR and TEM investigations. A different result was obtained for biocomposites after biomimetic treatment: an amorphous calcium phosphate on GO sheet was observed after 5 days of treatment. These different approaches resulted in a diverse effect on the proliferation and differentiation of osteogenic mesenchymal stem cells. In fact, in biocomposites prepared by the sol-gel approach the expression of an early marker of osteogenic differentiation, ALP, increases with the amount of GO in the first days of cell culture. Meanwhile, biomimetic materials sustain cell viability and proliferation, even if the expression of alkaline phosphatase activity in a basal medium is delayed. These findings may provide new prospects for utilizing GO-based hydroxyapatite biocomposites in bone repair, bone augmentation and coating of biomedical implants and broaden the application of GO sheets in biological areas. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  7. Nanocrystal thin film fabrication methods and apparatus

    Science.gov (United States)

    Kagan, Cherie R.; Kim, David K.; Choi, Ji-Hyuk; Lai, Yuming

    2018-01-09

    Nanocrystal thin film devices and methods for fabricating nanocrystal thin film devices are disclosed. The nanocrystal thin films are diffused with a dopant such as Indium, Potassium, Tin, etc. to reduce surface states. The thin film devices may be exposed to air during a portion of the fabrication. This enables fabrication of nanocrystal-based devices using a wider range of techniques such as photolithography and photolithographic patterning in an air environment.

  8. Biomimetic synthesis of modified calcium phosphate fine powders and their in vitro studies

    Energy Technology Data Exchange (ETDEWEB)

    Gergulova, R., E-mail: rumigg@yahoo.com; Tepavitcharova, S., E-mail: rumigg@yahoo.com; Rabadjieva, D., E-mail: rumigg@yahoo.com; Sezanova, K., E-mail: rumigg@yahoo.com; Ilieva, R., E-mail: rumigg@yahoo.com [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 11, 1113 Sofia (Bulgaria); Alexandrova, R.; Andonova-Lilova, B. [Institute of Experimental Morphology, Pathology and Anthropology with Museum, BAS, Acad. G. Bonchev Str., Bl. 25, Sofia (Bulgaria)

    2013-12-16

    Biomimetic approach and subsequent high-temperature treatment were used to synthesize ion modified calcium phosphate fine powders. Thus, using Simulated Body Fluid (SBF) as an ion modifier, a bi-phase mixture of ion modified β-tricalcium phosphate and hydroxyapatite (β-TCP + HA) was prepared. The use of SBF electrolyte solution enriched with Mg{sup 2+} or Zn{sup 2+} yielded monophase β-tricalcium phosphate additionally modified with Mg{sup 2+} or Zn{sup 2+} (Mg-β-TCP or Zn-β-TCP). The in vitro behavior of the prepared powders on cell viability and proliferation of murine BALB/c 3T3 fibroblasts and of human Lep 3 cells was studied by MTT test assays and Mosmann method after 72 h incubation. The relative cell viability was calculated.

  9. Biomimetic multidirectional scaffolds for zonal osteochondral tissue engineering via a lyophilization bonding approach.

    Science.gov (United States)

    Clearfield, Drew; Nguyen, Andrew; Wei, Mei

    2018-04-01

    The zonal organization of osteochondral tissue underlies its long term function. Despite this, tissue engineering strategies targeted for osteochondral repair commonly rely on the use of isotropic biomaterials for tissue reconstruction. There exists a need for a new class of highly biomimetic, anisotropic scaffolds that may allow for the engineering of new tissue with zonal properties. To address this need, we report the facile production of monolithic multidirectional collagen-based scaffolds that recapitulate the zonal structure and composition of osteochondral tissue. First, superficial and osseous zone-mimicking scaffolds were fabricated by unidirectional freeze casting collagen-hyaluronic acid and collagen-hydroxyapatite-containing suspensions, respectively. Following their production, a lyophilization bonding process was used to conjoin these scaffolds with a distinct collagen-hyaluronic acid suspension mimicking the composition of the transition zone. Resulting matrices contained a thin, highly aligned superficial zone that interfaced with a cellular transition zone and vertically oriented calcified cartilage and osseous zones. Confocal microscopy confirmed a zone-specific localization of hyaluronic acid, reflecting the depth-dependent increase of glycosaminoglycans in the native tissue. Poorly crystalline, carbonated hydroxyapatite was localized to the calcified cartilage and osseous zones and bordered the transition zone. Compressive testing of hydrated scaffold zones confirmed an increase of stiffness with scaffold depth, where compressive moduli of chondral and osseous zones fell within or near ranges conducive for chondrogenesis or osteogenesis of mesenchymal stem cells. With the combination of these biomimetic architectural and compositional cues, these multidirectional scaffolds hold great promise for the engineering of zonal osteochondral tissue. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 948-958, 2018. © 2017 Wiley Periodicals

  10. Enhancing Osteoconduction of PLLA-Based Nanocomposite Scaffolds for Bone Regeneration Using Different Biomimetic Signals to MSCs

    Directory of Open Access Journals (Sweden)

    Nicola Baldini

    2012-02-01

    Full Text Available In bone engineering, the adhesion, proliferation and differentiation of mesenchymal stromal cells rely on signaling from chemico-physical structure of the substrate, therefore prompting the design of mimetic “extracellular matrix”-like scaffolds. In this study, three-dimensional porous poly-L-lactic acid (PLLA-based scaffolds have been mixed with different components, including single walled carbon nanotubes (CNT, micro-hydroxyapatite particles (HA, and BMP2, and treated with plasma (PT, to obtain four different nanocomposites: PLLA + CNT, PLLA + CNTHA, PLLA + CNT + HA + BMP2 and PLLA + CNT + HA + PT. Adult bone marrow mesenchymal stromal cells (MSCs were derived from the femur of orthopaedic patients, seeded on the scaffolds and cultured under osteogenic induction up to differentiation and mineralization. The release of specific metabolites and temporal gene expression profiles of marrow-derived osteoprogenitors were analyzed at definite time points, relevant to in vitro culture as well as in vivo differentiation. As a result, the role of the different biomimetic components added to the PLLA matrix was deciphered, with BMP2-added scaffolds showing the highest biomimetic activity on cells differentiating to mature osteoblasts. The modification of a polymeric scaffold with reinforcing components which also work as biomimetic cues for cells can effectively direct osteoprogenitor cells differentiation, so as to shorten the time required for mineralization.

  11. Biomimetic Nanofibrillation in Two-Component Biopolymer Blends with Structural Analogs to Spider Silk

    Science.gov (United States)

    Xie, Lan; Xu, Huan; Li, Liang-Bin; Hsiao, Benjamin S.; Zhong, Gan-Ji; Li, Zhong-Ming

    2016-10-01

    Despite the enormous potential in bioinspired fabrication of high-strength structure by mimicking the spinning process of spider silk, currently accessible routes (e.g., microfluidic and electrospinning approaches) still have substantial function gaps in providing precision control over the nanofibrillar superstructure, crystalline morphology or molecular orientation. Here the concept of biomimetic nanofibrillation, by copying the spiders’ spinning principles, was conceived to build silk-mimicking hierarchies in two-phase biodegradable blends, strategically involving the stepwise integration of elongational shear and high-pressure shear. Phase separation confined on nanoscale, together with deformation of discrete phases and pre-alignment of polymer chains, was triggered in the elongational shear, conferring the readiness for direct nanofibrillation in the latter shearing stage. The orderly aligned nanofibrils, featuring an ultralow diameter of around 100 nm and the “rigid-soft” system crosslinked by nanocrystal domains like silk protein dopes, were secreted by fine nanochannels. The incorporation of multiscale silk-mimicking structures afforded exceptional combination of strength, ductility and toughness for the nanofibrillar polymer composites. The proposed spider spinning-mimicking strategy, offering the biomimetic function integration unattainable with current approaches, may prompt materials scientists to pursue biopolymer mimics of silk with high performance yet light weight.

  12. Biomimetic synthesis and morphological control of metal carbonates at the air/solution interface

    International Nuclear Information System (INIS)

    Lee, Shichoon; Cho, Kilwon; Son, Younggon

    2012-01-01

    Biomimetic approaches can provide a means of fabricating nanostructured materials under environmentally benign conditions. In this paper, we synthesized metal carbonate films, such as calcite, strontianite, malachite, and hydrozincite films, at the air-solution interface of solutions containing corresponding metal ions by using inflowing CO 2 from the atmosphere. The addition of acidic polymers, fulfilling the role of an acidic protein in biomineralization, provided CaCO 3 nanofibers, SrCO 3 nanofibers oriented in a specific direction, and copper carbonate and zinc carbonate hydroxide thin films. The metal carbonates prepared in this study were used as precursors for the formation of metal oxide nanocrystals via pyrolysis. This work showed that various metal carbonates and metal oxides with nanostructures can be prepared by using atmospheric CO 2 . - Highlights: ► Biomimetic synthesis of metal carbonate nanofilms at the air/solution interface. ► The reaction between metal ions and carbonate ions derived from CO 2 in the air. ► Calcium, strontium, copper and zinc carbonates were formed. ► The morphologies of the nanofilms were controlled by adding the acidic polymer. ► Nanostructured metal oxides were prepared by pyrolysis of the metal carbonates.

  13. Exquisite Enzyme-Fenton Biomimetic Catalysts for Hydroxyl Radical Production by Mimicking an Enzyme Cascade.

    Science.gov (United States)

    Zhang, Qi; Chen, Shuo; Wang, Hua; Yu, Hongtao

    2018-03-14

    Hydrogen peroxide (H 2 O 2 ) is a key reactant in the Fenton process. As a byproduct of enzymatic reaction, H 2 O 2 can be obtained via catalytical oxidation of glucose using glucose oxidase in the presence of O 2 . Another oxidation product (gluconic acid) can suitably adjust the microenvironmental pH contributing to the Fe 3+ /Fe 2+ cycle in the Fenton reaction. Enzymes are extremely efficient at catalyzing a variety of reactions with high catalytic activity, substrate specificity, and yields in living organisms. Inspired by the multiple functions of natural multienzyme systems, an exquisite nanozyme-modified α-FeOOH/porous carbon (PC) biomimetic catalyst constructed by in situ growth of glucose oxidase-mimicking Au nanoparticles and crystallization of adsorbed ferric ions within carboxyl into hierarchically PC is developed as an efficient enzyme-Fenton catalyst. The products (H 2 O 2 , ∼4.07 mmol·L -1 ) of the first enzymatic reaction are immediately used as substrates for the second Fenton-like reaction to generate the valuable • OH (∼96.84 μmol·L -1 ), thus mimicking an enzyme cascade pathway. α-FeOOH nanocrystals, attached by C-O-Fe bondings, are encapsulated into the mesoporous PC frameworks, facilitating the electron transfer between α-FeOOH and the PC support and greatly suppressing iron leaching. This study paves a new avenue for designing biomimetic enzyme-based Fenton catalysts mimicking a natural system for • OH production.

  14. Hydroxyapatite-diamondlike carbon nanocomposite films

    International Nuclear Information System (INIS)

    Narayan, Roger J.

    2005-01-01

    Hydroxyapatite is a bioactive ceramic that mimics the mineral composition of natural bone. Conventional plasma-sprayed hydroxyapatite coatings demonstrate poor adhesion and poor mechanical integrity. We have developed hydroxyapatite-diamondlike carbon bilayer film. The diamondlike carbon interlayer serves to prevent metal ion release and improve adhesion of the hydroxyapatite film. These films were characterized using X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, nanoindentation, and microscratch adhesion testing. Based on the results of this study, hydroxyapatite-diamondlike carbon bilayers demonstrate promise for use in several orthopedic implants

  15. Hydroxyapatite-diamondlike carbon nanocomposite films

    Energy Technology Data Exchange (ETDEWEB)

    Narayan, Roger J. [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245 (United States)]. E-mail: roger.narayan@mse.gatech.edu

    2005-05-15

    Hydroxyapatite is a bioactive ceramic that mimics the mineral composition of natural bone. Conventional plasma-sprayed hydroxyapatite coatings demonstrate poor adhesion and poor mechanical integrity. We have developed hydroxyapatite-diamondlike carbon bilayer film. The diamondlike carbon interlayer serves to prevent metal ion release and improve adhesion of the hydroxyapatite film. These films were characterized using X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, nanoindentation, and microscratch adhesion testing. Based on the results of this study, hydroxyapatite-diamondlike carbon bilayers demonstrate promise for use in several orthopedic implants.

  16. Dense and porous titanium substrates with a biomimetic calcium phosphate coating

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, A.A., E-mail: aantunesr@yahoo.com.br [Powder Technology Laboratory, Materials Processing and Characterization Division, National Institute of Technology, No. 82 Venezuela Avenue, Room 602, 20081-312 Rio de Janeiro, RJ (Brazil); Balestra, R.M. [Powder Technology Laboratory, Materials Processing and Characterization Division, National Institute of Technology, No. 82 Venezuela Avenue, Room 602, 20081-312 Rio de Janeiro, RJ (Brazil); Rocha, M.N. [Metallurgical and Materials Engineering Program, COPPE, Federal University of Rio de Janeiro, P.O. Box 68505, 21941-972 Rio de Janeiro, RJ (Brazil); Peripolli, S.B. [Materials Metrology Division, National Institute of Metrology, Normalization and Quality, No. 50 Nossa Senhora das Gracas Street, Building 3, 25250-020 Duque de Caxias, RJ (Brazil); Andrade, M.C. [Polytechnic Institute of Rio de Janeiro, Rio de Janeiro State University, s/n, Alberto Rangel Street, 28630-050 Nova Friburgo, RJ (Brazil); Pereira, L.C. [Metallurgical and Materials Engineering Program, COPPE, Federal University of Rio de Janeiro, P.O. Box 68505, 21941-972 Rio de Janeiro, RJ (Brazil); Oliveira, M.V. [Powder Technology Laboratory, Materials Processing and Characterization Division, National Institute of Technology, No. 82 Venezuela Avenue, Room 602, 20081-312 Rio de Janeiro, RJ (Brazil)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer A biomimetic coating method with simplified solution is proposed. Black-Right-Pointing-Pointer Titanium substrates are submitted to chemical and heat treatments. Black-Right-Pointing-Pointer Titanium substrates are coated with biocompatible calcium phosphate phases. Black-Right-Pointing-Pointer The simplified solution shows potential to be applied as a coating technique. - Abstract: The present work studied a biomimetic method using a simplified solution (SS) with calcium and phosphorus ions for coating titanium substrates, in order to improve their bioactivity. Commercially pure titanium dense sheet, microporous and macroporous titanium samples, both produced by powder metallurgy, were treated in NaOH solution followed by heat-treating and immersed in SS for 7, 14 or 21 days. The samples characterization was performed by quantitative metallographic analysis, confocal scanning optical microscopy, scanning electron microscopy, energy dispersive spectroscopy and low angle X-ray diffraction. The results showed coatings with calcium phosphate precipitation in all samples, with globular or plate-like morphology, typical of hydroxyapatite and octacalcium phosphate, respectively, indicating that the solution (SS) has potential for coating titanium substrates. In addition, the different surfaces of substrates had an effect on the formed calcium phosphate phase and thickness of coatings, depending on the substrate type and imersion time in the simplified solution.

  17. Fabrication of highly porous biodegradable biomimetic nanocomposite as advanced bone tissue scaffold

    Directory of Open Access Journals (Sweden)

    Abdalla Abdal-hay

    2017-02-01

    Full Text Available Development of bioinspired or biomimetic materials is currently a challenge in the field of tissue regeneration. In-situ 3D biomimetic microporous nanocomposite scaffold has been developed using a simple lyophilization post hydrothermal reaction for bone healing applications. The fabricated 3D porous scaffold possesses advantages of good bonelike apatite particles distribution, thermal properties and high porous interconnected network structure. High dispersion bonelike apatite nanoparticles (NPs rapidly nucleated and deposited from surrounding biological minerals within chitosan (CTS matrices using hydrothermal technique. After that, freeze-drying method was applied on the composite solution to form the desired porous 3D architecture. Interestingly, the porosity and pore size of composite scaffold were not significantly affected by the particles size and particles content within the CTS matrix. Our results demonstrated that the compression modulus of porous composite scaffold is twice higher than that of plain CTS scaffold, indicating a maximization of the chemical interaction between polymer matrix and apatite NPs. Cytocompatibility test for MC3T3-E1 pre-osteoblasts cell line using MTT-indirect assay test showed that the fabricated 3D microporous nanocomposite scaffold possesses higher cell proliferation and growth than that of pure CTS scaffold. Collectively, our results suggest that the newly developed highly porous apatite/CTS nanocomposite scaffold as an alternative of hydroxyapatite/CTS scaffold may serve as an excellent porous 3D platform for bone tissue regeneration.

  18. Synthesis of chitosan/hydroxyapatite membranes coated with hydroxycarbonate apatite for guided tissue regeneration purposes

    Energy Technology Data Exchange (ETDEWEB)

    Fraga, Alexandre Felix [Federal University of Sao Carlos, Department of Materials Engineering, DEMa, UFSCar, Sao Carlos, SP (Brazil); Almeida Filho, Edson de, E-mail: edsonafilho@yahoo.com.br [University Estadual Paulista, Department of Physical Chemistry - IQ, Araraquara, SP (Brazil); Silva Rigo, Eliana Cristina da [University of Sao Paulo, Department of Basic Science - FZEA-ZAB, Pirassununga, SP (Brazil); Ortega Boschi, Anselmo [Federal University of Sao Carlos, Department of Materials Engineering, DEMa, UFSCar, Sao Carlos, SP (Brazil)

    2011-02-15

    Chitosan, which is a non-toxic, biodegradable and biocompatible biopolymer, has been widely researched for several applications in the field of biomaterials. Calcium phosphate ceramics stand out among the so-called bioceramics for their absence of local or systemic toxicity, their non-response to foreign bodies or inflammations, and their apparent ability to bond to the host tissue. Hydroxyapatite (HA) is one of the most important bioceramics because it is the main component of the mineral phase of bone. The aim of this work was to produce chitosan membranes coated with hydroxyapatite using the modified biomimetic method. Membranes were synthesized from a solution containing 2% of chitosan in acetic acid (weight/volume) via the solvent evaporation method. Specimens were immersed in a sodium silicate solution and then in a 1.5 SBF (simulated body fluid) solution. The crystallinity of the HA formed over the membranes was correlated to the use of the nucleation agent (the sodium silicate solution itself). Coated membranes were characterized by means of scanning electron microscopy - SEM, X-ray diffraction - XRD, and Fourier transform infrared spectroscopy - FTIR. The results indicate a homogeneous coating covering the entire surface of the membrane and the production of a semi-crystalline hydroxyapatite layer similar to the mineral phase of human bone.

  19. Multi-Functions of Carbonated Calcium Deficient Hydroxyapatite (CDHA)

    Science.gov (United States)

    Zhou, Huan

    Natural bone is a complex composite mainly constituted of inorganic minerals and organic collagen molecules. Calcium phosphate (CaP) based materials have been proposed as the predominant bone substitute for bone tissue engineering applications due to their chemical similarity to bone mineral. Amorphous carbonated calcium deficient hydroxyapatite (CDHA) is an important compound among CaP materials because of the amorphous crystallite structure. The presence of extra ions in its lattice structure not only influences cell attachment and proliferation of osteoblasts, but also helps in bone metabolism. Biomimetic coating approach is the most widely used approach to produce CDHA coatings to implant. It is a process using simulated body fluid (SBF) to deposit bone-like CDHA coating to various material surfaces. The CDHA formation mechanism, SBF compositions and reacting conditions of biomimetic coating have already been sufficiently studied and compared in the past 20 years. It is an attempt in this thesis to explore new applications of SBF in biomedical research, focusing on different biomaterial applications: 1) based on the low temperature reaction condition of SBF, bisphosphonate incorporated CDHA coatings were deposited onto Ti6Al4V surface for the treatment of osteoporosis; 2) amorphous calcium phosphate nanospheres with extra elements in the lattice structure were prepared by a novel microwave assisted approach, providing a new potential of CaP materials production; 3) CDHA particles formed in SBF can be used as great fillers with biopolymers for preparing biocomposites for biomedical applications; 4) based on the high activity of CDHA amorphous structure and the stabilization ability of ethanol, yttrium and europium doped calcium phosphates were prepared using CDHA as a sacrificing template. In the end, future work based on these observations in the thesis is addressed, including areas of drug delivery, biocomposite fabrication and preparation of functionalized

  20. Bio-mimetic mineralization potential of collagen hydrolysate obtained from chromium tanned leather waste

    International Nuclear Information System (INIS)

    Banerjee, Pradipta; Madhu, S.; Chandra Babu, N.K.; Shanthi, C.

    2015-01-01

    Hydroxyapatite (HA) ceramics serve as an alternative to autogenous-free bone grafting by virtue of their excellent biocompatibility. However, chemically synthesized HA lacks the strong load-bearing capacity as required by bone. The bio-mimetic growth of HA crystals on collagen surface provides a feasible solution for synthesizing bone substitutes with the desired properties. This study deals with the utilization of the collagen hydrolysate recovered from leather waste as a substrate for promoting HA crystal growth. Bio-mimetic growth of HA was induced by subjecting the hydrolysate to various mineralization conditions. Parameters that would have a direct effect on crystal growth were varied to determine the optimal conditions necessary. Maximum mineralization was achieved with a combination of 10 mM of CaCl 2 , 5 mM of Na 2 HPO 4 , 100 mM of NaCl and 0.575% glutaraldehyde at a pH of 7.4. The metal–protein interactions leading to formation of HA were identified through Fourier-transform infrared (FTIR) spectroscopy and x-ray diffraction (XRD) studies. The crystal dimensions were determined to be in the nanoscale range by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The size and crystallinity of bio-mimetically grown HA indicate that hydrolysate from leather waste can be used as an ideal alternative substrate for bone growth. - Highlights: • Collagen hydrolysate, extracted from leather industry waste is subjected to biomineralization. • Optimal conditions required for HA growth are identified. • FTIR studies reveal higher Ca−COO − and low C−N stretch with higher HA formation. • AFM and SEM studies reveal nanometer ranged HA crystals

  1. Integrating biologically inspired nanomaterials and table-top stereolithography for 3D printed biomimetic osteochondral scaffolds

    Science.gov (United States)

    Castro, Nathan J.; O'Brien, Joseph; Zhang, Lijie Grace

    2015-08-01

    The osteochondral interface of an arthritic joint is notoriously difficult to regenerate due to its extremely poor regenerative capacity and complex stratified architecture. Native osteochondral tissue extracellular matrix is composed of numerous nanoscale organic and inorganic constituents. Although various tissue engineering strategies exist in addressing osteochondral defects, limitations persist with regards to tissue scaffolding which exhibit biomimetic cues at the nano to micro scale. In an effort to address this, the current work focused on 3D printing biomimetic nanocomposite scaffolds for improved osteochondral tissue regeneration. For this purpose, two biologically-inspired nanomaterials have been synthesized consisting of (1) osteoconductive nanocrystalline hydroxyapatite (nHA) (primary inorganic component of bone) and (2) core-shell poly(lactic-co-glycolic) acid (PLGA) nanospheres encapsulated with chondrogenic transforming growth-factor β1 (TGF-β1) for sustained delivery. Then, a novel table-top stereolithography 3D printer and the nano-ink (i.e., nHA + nanosphere + hydrogel) were employed to fabricate a porous and highly interconnected osteochondral scaffold with hierarchical nano-to-micro structure and spatiotemporal bioactive factor gradients. Our results showed that human bone marrow-derived mesenchymal stem cell adhesion, proliferation, and osteochondral differentiation were greatly improved in the biomimetic graded 3D printed osteochondral construct in vitro. The current work served to illustrate the efficacy of the nano-ink and current 3D printing technology for efficient fabrication of a novel nanocomposite hydrogel scaffold. In addition, tissue-specific growth factors illustrated a synergistic effect leading to increased cell adhesion and directed stem cell differentiation.

  2. Electrospinning of calcium carbonate fibers and their conversion to nanocrystalline hydroxyapatite

    International Nuclear Information System (INIS)

    Holopainen, Jani; Santala, Eero; Heikkilä, Mikko; Ritala, Mikko

    2014-01-01

    Calcium carbonate (CaCO 3 ) fibers were prepared by electrospinning followed by annealing. Solutions consisting of calcium nitrate tetrahydrate (Ca(NO 3 ) 2 ·4H 2 O) and polyvinylpyrrolidone (PVP) dissolved in ethanol or 2-methoxyethanol were used for the fiber preparation. By varying the precursor concentrations in the electrospinning solutions CaCO 3 fibers with average diameters from 140 to 290 nm were obtained. After calcination the fibers were identified as calcite by X-ray diffraction (XRD). The calcination process was studied in detail with high temperature X-ray diffraction (HTXRD) and thermogravimetric analysis (TGA). The initially weak fiber-to-substrate adhesion was improved by adding a strengthening CaCO 3 layer by spin or dip coating Ca(NO 3 ) 2 /PVP precursor solution on the CaCO 3 fibers followed by annealing of the gel formed inside the fiber layer. The CaCO 3 fibers were converted to nanocrystalline hydroxyapatite (HA) fibers by treatment in a dilute phosphate solution. The resulting hydroxyapatite had a plate-like crystal structure with resemblance to bone mineral. The calcium carbonate and hydroxyapatite fibers are interesting materials for bone scaffolds and bioactive coatings. - Highlights: • Calcium carbonate fibers were prepared by electrospinning. • The electrospun fibers crystallized to calcite upon calcination at 500 °C. • Spin and dip coating methods were used to improve the adhesion of the CaCO 3 fibers. • The CaCO 3 fibers were converted to hydroxyapatite by treatment in phosphate solution. • The hydroxyapatite fibers consisted of plate-like nanocrystals

  3. Electrospinning of calcium carbonate fibers and their conversion to nanocrystalline hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Holopainen, Jani, E-mail: jani.holopainen@helsinki.fi; Santala, Eero; Heikkilä, Mikko; Ritala, Mikko

    2014-12-01

    Calcium carbonate (CaCO{sub 3}) fibers were prepared by electrospinning followed by annealing. Solutions consisting of calcium nitrate tetrahydrate (Ca(NO{sub 3}){sub 2}·4H{sub 2}O) and polyvinylpyrrolidone (PVP) dissolved in ethanol or 2-methoxyethanol were used for the fiber preparation. By varying the precursor concentrations in the electrospinning solutions CaCO{sub 3} fibers with average diameters from 140 to 290 nm were obtained. After calcination the fibers were identified as calcite by X-ray diffraction (XRD). The calcination process was studied in detail with high temperature X-ray diffraction (HTXRD) and thermogravimetric analysis (TGA). The initially weak fiber-to-substrate adhesion was improved by adding a strengthening CaCO{sub 3} layer by spin or dip coating Ca(NO{sub 3}){sub 2}/PVP precursor solution on the CaCO{sub 3} fibers followed by annealing of the gel formed inside the fiber layer. The CaCO{sub 3} fibers were converted to nanocrystalline hydroxyapatite (HA) fibers by treatment in a dilute phosphate solution. The resulting hydroxyapatite had a plate-like crystal structure with resemblance to bone mineral. The calcium carbonate and hydroxyapatite fibers are interesting materials for bone scaffolds and bioactive coatings. - Highlights: • Calcium carbonate fibers were prepared by electrospinning. • The electrospun fibers crystallized to calcite upon calcination at 500 °C. • Spin and dip coating methods were used to improve the adhesion of the CaCO{sub 3} fibers. • The CaCO{sub 3} fibers were converted to hydroxyapatite by treatment in phosphate solution. • The hydroxyapatite fibers consisted of plate-like nanocrystals.

  4. Semiconductor Nanocrystals for Biological Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Aihua; Gu, Weiwei; Larabell, Carolyn; Alivisatos, A. Paul

    2005-06-28

    Conventional organic fluorophores suffer from poor photo stability, narrow absorption spectra and broad emission feature. Semiconductor nanocrystals, on the other hand, are highly photo-stable with broad absorption spectra and narrow size-tunable emission spectra. Recent advances in the synthesis of these materials have resulted in bright, sensitive, extremely photo-stable and biocompatible semiconductor fluorophores. Commercial availability facilitates their application in a variety of unprecedented biological experiments, including multiplexed cellular imaging, long-term in vitro and in vivo labeling, deep tissue structure mapping and single particle investigation of dynamic cellular processes. Semiconductor nanocrystals are one of the first examples of nanotechnology enabling a new class of biomedical applications.

  5. Biomimetic apatite-coated porous PVA scaffolds promote the growth of breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Mao; Mohanty, Pravansu; Ghosh, Gargi, E-mail: gargi@umich.edu

    2014-11-01

    Recapitulating the native environment of bone tissue is essential to develop in vitro models of breast cancer bone metastasis. The bone is a composite material consisting of organic matrix and inorganic mineral phase, primarily hydroxyapatite. In this study, we report the mineralization of porous poly vinyl alcohol (PVA) scaffolds upon incubation in modified Hanks' Balanced Salt Solution (HBSS) for 14 days. Scanning electron microscopy, energy dispersive X-ray analysis, and X-ray diffraction analysis revealed that the deposited minerals have composition similar to hydroxyapatite. The study demonstrated that the rate of nucleation and growth of minerals was faster on surfaces of less porous scaffolds. However, upon prolonged incubation, formation of mineral layer was observed on the surface of all the scaffolds. In addition, the study also demonstrated that 3D mineralization only occurred for scaffolds with highly interconnected porous networks. The mineralization of the scaffolds promoted the adsorption of serum proteins and consequently, the adhesion and proliferation of breast cancer cells. - Highlights: • Porous PVA scaffolds fabricated via mechanical agitation followed by freeze-drying. • Mineralization of the scaffold was carried out by utilizing biomimetic approach. • Mineralization resulted in increased protein adsorption on the scaffold. • Increased breast cancer cell growth was observed on mineralized scaffolds.

  6. Biomimetic apatite-coated porous PVA scaffolds promote the growth of breast cancer cells

    International Nuclear Information System (INIS)

    Ye, Mao; Mohanty, Pravansu; Ghosh, Gargi

    2014-01-01

    Recapitulating the native environment of bone tissue is essential to develop in vitro models of breast cancer bone metastasis. The bone is a composite material consisting of organic matrix and inorganic mineral phase, primarily hydroxyapatite. In this study, we report the mineralization of porous poly vinyl alcohol (PVA) scaffolds upon incubation in modified Hanks' Balanced Salt Solution (HBSS) for 14 days. Scanning electron microscopy, energy dispersive X-ray analysis, and X-ray diffraction analysis revealed that the deposited minerals have composition similar to hydroxyapatite. The study demonstrated that the rate of nucleation and growth of minerals was faster on surfaces of less porous scaffolds. However, upon prolonged incubation, formation of mineral layer was observed on the surface of all the scaffolds. In addition, the study also demonstrated that 3D mineralization only occurred for scaffolds with highly interconnected porous networks. The mineralization of the scaffolds promoted the adsorption of serum proteins and consequently, the adhesion and proliferation of breast cancer cells. - Highlights: • Porous PVA scaffolds fabricated via mechanical agitation followed by freeze-drying. • Mineralization of the scaffold was carried out by utilizing biomimetic approach. • Mineralization resulted in increased protein adsorption on the scaffold. • Increased breast cancer cell growth was observed on mineralized scaffolds

  7. Biomimetic heterogenous elastic tissue development.

    Science.gov (United States)

    Tsai, Kai Jen; Dixon, Simon; Hale, Luke Richard; Darbyshire, Arnold; Martin, Daniel; de Mel, Achala

    2017-01-01

    There is an unmet need for artificial tissue to address current limitations with donor organs and problems with donor site morbidity. Despite the success with sophisticated tissue engineering endeavours, which employ cells as building blocks, they are limited to dedicated labs suitable for cell culture, with associated high costs and long tissue maturation times before available for clinical use. Direct 3D printing presents rapid, bespoke, acellular solutions for skull and bone repair or replacement, and can potentially address the need for elastic tissue, which is a major constituent of smooth muscle, cartilage, ligaments and connective tissue that support organs. Thermoplastic polyurethanes are one of the most versatile elastomeric polymers. Their segmented block copolymeric nature, comprising of hard and soft segments allows for an almost limitless potential to control physical properties and mechanical behaviour. Here we show direct 3D printing of biocompatible thermoplastic polyurethanes with Fused Deposition Modelling, with a view to presenting cell independent in-situ tissue substitutes. This method can expeditiously and economically produce heterogenous, biomimetic elastic tissue substitutes with controlled porosity to potentially facilitate vascularisation. The flexibility of this application is shown here with tubular constructs as exemplars. We demonstrate how these 3D printed constructs can be post-processed to incorporate bioactive molecules. This efficacious strategy, when combined with the privileges of digital healthcare, can be used to produce bespoke elastic tissue substitutes in-situ, independent of extensive cell culture and may be developed as a point-of-care therapy approach.

  8. Biomimetic superwettable materials with structural colours.

    Science.gov (United States)

    Wang, Zelinlan; Guo, Zhiguang

    2017-12-05

    Structural colours and superwettability are of great interest due to their unique characteristics. However, the application of materials with either structural colours or superwettability is limited. Moreover, materials possessing both structural colours and superwettability are crucial for many practical applications. The combination of structural colours and superwettability can result in materials for use various applications, such as in sensors, detectors, bioassays, anti-counterfeiting, and liquid actuators, by controlling surfaces to repel or absorb liquids. Regarding superwettability and structural colours, surface texture and chemical composition are two factors for the construction of materials with superwettable structural colours. This review aims at offering a comprehensive elaboration of the mechanism, recent biomimetic research, and applications of biomimetic superwettable materials with structural colours. Furthermore, this review provides significant insight into the design, fabrication, and application of biomimetic superwettable materials with structural colours.

  9. Laser technology in biomimetics basics and applications

    CERN Document Server

    Belegratis, Maria

    2013-01-01

    Lasers are progressively more used as versatile tools for fabrication purposes. The wide range of available powers, wavelengths, operation modes, repetition rates etc. facilitate the processing of a large spectrum of materials at exceptional precision and quality. Hence, manifold methods were established in the past and novel methods are continuously under development. Biomimetics, the translation from nature-inspired principles to technical applications, is strongly multidisciplinary. This field offers intrinsically a wide scope of applications for laser based methods regarding structuring and modification of materials. This book is dedicated to laser fabrication methods in biomimetics. It introduces both, a laser technology as well as an application focused approach.  The book covers the most important laser lithographic methods and various biomimetics application scenarios ranging from coatings and biotechnology to construction, medical applications and photonics.

  10. Challenges in biomimetic design and innovation

    DEFF Research Database (Denmark)

    Lenau, Torben Anker; Barfoed, Michael; Shu, Li

    Biomimetic design copies desired principles found in nature and implement them into artificial applications. Applications could be products we use in our daily life but it can also be used to inspire material innovation. However there are significant challenges in performing biomimetic design. One....... This is a key issue in design and innovation work where problem identification and systematic search for suitable solution principle are major activities. One way to deal with this challenge is to use a biology search method. The use of such a method is illustrated with a case story describing the design...... including the terminology and knowledge organisation. It is often easy to recognise the splendour of a biological solution, but it can be much more difficult to understand the underlying mechanisms. Another challenge in biomimetic design is the search and identification of relevant solutions in nature...

  11. Rapid biomimetic mineralization of collagen fibrils and combining with human umbilical cord mesenchymal stem cells for bone defects healing

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Bihua; Luo, Xueshi; Li, Zhiwen [Department of Material Science and Engineering, Engineering Research Center of Artificial Organs and Materials, Jinan University, Guangzhou 510632 (China); Zhuang, Caiping [Department of Anesthesiology, Huizhou Central People' s Hospital, Huizhou 516001 (China); Li, Lihua, E-mail: tlihuali@jnu.edu.cn [Department of Material Science and Engineering, Engineering Research Center of Artificial Organs and Materials, Jinan University, Guangzhou 510632 (China); Lu, Lu; Ding, Shan; Tian, Jinhuan [Department of Material Science and Engineering, Engineering Research Center of Artificial Organs and Materials, Jinan University, Guangzhou 510632 (China); Zhou, Changren, E-mail: tcrz9@jnu.edu.cn [Department of Material Science and Engineering, Engineering Research Center of Artificial Organs and Materials, Jinan University, Guangzhou 510632 (China)

    2016-11-01

    Collagen biomineralization is regulated by complicated interactions between the collagen matrix and non-collagenous extracellular proteins. Here, the use of sodium tripolyphosphate to simulate the templating functional motif of the C-terminal fragment of non-collagenous proteins is reported, and a low molecular weight polyacrylic acid served as a sequestration agent to stabilize amorphous calcium phosphate into nanoprecursors. Self-assembled collagen fibrils served as a fixed template for achieving rapid biomimetic mineralization in vitro. Results demonstrated that, during the mineralization process, intrafibrillar and extrafibrillar hydroxyapatite mineral with collagen fibrils formed and did so via bottom-up nanoparticle assembly based on the non-classical crystallization approach in the presence of these dual biomimetic functional analogues. In vitro human umbilical cord mesenchymal stem cell (hUCMSC) culture found that the mineralized scaffolds have a better cytocompatibility in terms of cell viability, adhesion, proliferation, and differentiation into osteoblasts. A rabbit femoral condyle defect model was established to confirm the ability of the n-HA/collagen scaffolds to facilitate bone regeneration and repair. The images of gross anatomy, MRI, CT and histomorphology taken 6 and 12 weeks after surgery showed that the biomimetic mineralized collagen scaffolds with hUCMSCs can promote the healing speed of bone defects in vivo, and both of the scaffolds groups performing better than the bone defect control group. As new bone tissue formed, the scaffolds degraded and were gradually absorbed. All these results demonstrated that both of the scaffolds and cells have better histocompatibility. - Highlights: • A rapid and facile biomimetic mineralization approach is proposed. • Intrafibrillar and extrafibrillar mineralization of collagen fibrils was achieved. • HA/COL scaffolds promote hUCMSCs adhesion, proliferation, and differentiation. • Feasibility of h

  12. Rapid biomimetic mineralization of collagen fibrils and combining with human umbilical cord mesenchymal stem cells for bone defects healing

    International Nuclear Information System (INIS)

    Ye, Bihua; Luo, Xueshi; Li, Zhiwen; Zhuang, Caiping; Li, Lihua; Lu, Lu; Ding, Shan; Tian, Jinhuan; Zhou, Changren

    2016-01-01

    Collagen biomineralization is regulated by complicated interactions between the collagen matrix and non-collagenous extracellular proteins. Here, the use of sodium tripolyphosphate to simulate the templating functional motif of the C-terminal fragment of non-collagenous proteins is reported, and a low molecular weight polyacrylic acid served as a sequestration agent to stabilize amorphous calcium phosphate into nanoprecursors. Self-assembled collagen fibrils served as a fixed template for achieving rapid biomimetic mineralization in vitro. Results demonstrated that, during the mineralization process, intrafibrillar and extrafibrillar hydroxyapatite mineral with collagen fibrils formed and did so via bottom-up nanoparticle assembly based on the non-classical crystallization approach in the presence of these dual biomimetic functional analogues. In vitro human umbilical cord mesenchymal stem cell (hUCMSC) culture found that the mineralized scaffolds have a better cytocompatibility in terms of cell viability, adhesion, proliferation, and differentiation into osteoblasts. A rabbit femoral condyle defect model was established to confirm the ability of the n-HA/collagen scaffolds to facilitate bone regeneration and repair. The images of gross anatomy, MRI, CT and histomorphology taken 6 and 12 weeks after surgery showed that the biomimetic mineralized collagen scaffolds with hUCMSCs can promote the healing speed of bone defects in vivo, and both of the scaffolds groups performing better than the bone defect control group. As new bone tissue formed, the scaffolds degraded and were gradually absorbed. All these results demonstrated that both of the scaffolds and cells have better histocompatibility. - Highlights: • A rapid and facile biomimetic mineralization approach is proposed. • Intrafibrillar and extrafibrillar mineralization of collagen fibrils was achieved. • HA/COL scaffolds promote hUCMSCs adhesion, proliferation, and differentiation. • Feasibility of h

  13. Tissue bionics: examples in biomimetic tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Green, David W [Bone and Joint Research Group, Developmental Origins of Health and Disease, General Hospital, University of Southampton, SO16 6YD (United Kingdom)], E-mail: Hindoostuart@googlemail.com

    2008-09-01

    Many important lessons can be learnt from the study of biological form and the functional design of organisms as design criteria for the development of tissue engineering products. This merging of biomimetics and regenerative medicine is termed 'tissue bionics'. Clinically useful analogues can be generated by appropriating, modifying and mimicking structures from a diversity of natural biomatrices ranging from marine plankton shells to sea urchin spines. Methods in biomimetic materials chemistry can also be used to fabricate tissue engineering scaffolds with added functional utility that promise human tissues fit for the clinic.

  14. Tissue bionics: examples in biomimetic tissue engineering

    International Nuclear Information System (INIS)

    Green, David W

    2008-01-01

    Many important lessons can be learnt from the study of biological form and the functional design of organisms as design criteria for the development of tissue engineering products. This merging of biomimetics and regenerative medicine is termed 'tissue bionics'. Clinically useful analogues can be generated by appropriating, modifying and mimicking structures from a diversity of natural biomatrices ranging from marine plankton shells to sea urchin spines. Methods in biomimetic materials chemistry can also be used to fabricate tissue engineering scaffolds with added functional utility that promise human tissues fit for the clinic

  15. Biomimetic microsensors inspired by marine life

    CERN Document Server

    Kottapalli, Ajay Giri Prakash; Miao, Jianmin; Triantafyllou, Michael S

    2017-01-01

    This book narrates the development of various biomimetic microelectromechanical systems (MEMS) sensors, such as pressure, flow, acceleration, chemical, and tactile sensors, that are inspired by sensing phenomenon that exist in marine life. The research described in this book is multi-faceted and combines the expertise and understanding from diverse fields, including biomimetics, microfabrication, sensor engineering, MEMS design, nanotechnology, and material science. A series of chapters examine the design and fabrication of MEMS sensors that function on piezoresistive, piezoelectric, strain gauge, and chemical sensing principles. By translating nature-based engineering solutions to artificial manmade technology, we could find innovative solutions to critical problems.

  16. Do Biomimetic Students Think Outside the Box?

    DEFF Research Database (Denmark)

    Lenau, Torben Anker

    2017-01-01

    analysed. The empirical material comprises 111 students working on 28 different functional design problems. On average teams identify 9.0 relevant biological phenomena and manage to produce a physical proof-of-principle for the selected biological analogy. 39% of the analogies can be characterised as well...... phenomena? If they concentrate on animals and plants, which they beforehand have knowledge about, it could be expected that solutions will remind of what they would have found without using biomimetics. To investigate this question, the empirical results from a university course in biomimetics have been...

  17. Biomimetic membranes for sensor and separation applications

    DEFF Research Database (Denmark)

    Helix Nielsen, Claus

    2009-01-01

    preventing the passage of others, a property critical for the overall conservation of the cells internal pH and salt concentration. Both ion and water channels are highly efficient membrane pore proteins capable of transporting solutes at very high rates, up to 109 molecules per second. Carrier proteins...... and biomimetic support matrix. Also the stability of the incorporated protein must be addressed and the protein-biomimetic matrix must be encapsulated in order to protect it and make it sufficiently stable in a final application. Here I will review and discuss these challenges and how they are met in some...

  18. Evaporation-induced assembly of biomimetic polypeptides

    International Nuclear Information System (INIS)

    Keyes, Joseph; Junkin, Michael; Cappello, Joseph; Wu Xiaoyi; Wong, Pak Kin

    2008-01-01

    We report an evaporation assisted plasma lithography (EAPL) process for guided self-assembly of a biomimetic silk-elastinlike protein (SELP). We demonstrate the formation of SELP structures from millimeter to submicrometer range on plasma-treatment surface templates during an evaporation-induced self-assembly process. The self-assembly processes at different humidities and droplet volumes were investigated. The process occurs efficiently in a window of optimized operating conditions found to be at 70% relative humidity and 8 μl volume of SELP solution. The EAPL approach provides a useful technique for the realization of functional devices and systems using these biomimetic materials

  19. Doping effect in Si nanocrystals

    Science.gov (United States)

    Li, Dongke; Xu, Jun; Zhang, Pei; Jiang, Yicheng; Chen, Kunji

    2018-06-01

    Intentional doping in semiconductors is a fundamental issue since it can control the conduction type and ability as well as modify the optical and electronic properties. To realize effective doping is the basis for developing semiconductor devices. However, by reducing the size of a semiconductor, like Si, to the nanometer scale, the doping effects become complicated due to the coupling between the quantum confinement effect and the surfaces and/or interfaces effect. In particular, by introducing phosphorus or boron impurities as dopants into material containing Si nanocrystals with a dot size of less than 10 nm, it exhibits different behaviors and influences on the physical properties from its bulk counterpart. Understanding the doping effects in Si nanocrystals is currently a challenge in order to further improve the performance of the next generation of nano-electronic and photonic devices. In this review, we present an overview of the latest theoretical studies and experimental results on dopant distributions and their effects on the electronic and optical properties of Si nanocrystals. In particular, the advanced characterization techniques on dopant distribution, the carrier transport process as well as the linear and nonlinear optical properties of doped Si nanocrystals, are systematically summarized.

  20. "Nanocrystal bilayer for tandem catalysis"

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Yusuke; Tsung, Chia Kuang; Huang, Wenyu; Huo, Ziyang; E.Habas, Susan E; Soejima, Tetsuro; Aliaga, Cesar E; Samorjai, Gabor A; Yang, Peidong

    2011-01-24

    Supported catalysts are widely used in industry and can be optimized by tuning the composition and interface of the metal nanoparticles and oxide supports. Rational design of metal-metal oxide interfaces in nanostructured catalysts is critical to achieve better reaction activities and selectivities. We introduce here a new class of nanocrystal tandem catalysts that have multiple metal-metal oxide interfaces for the catalysis of sequential reactions. We utilized a nanocrystal bilayer structure formed by assembling platinum and cerium oxide nanocube monolayers of less than 10 nm on a silica substrate. The two distinct metal-metal oxide interfaces, CeO2-Pt and Pt-SiO2, can be used to catalyse two distinct sequential reactions. The CeO2-Pt interface catalysed methanol decomposition to produce CO and H2, which were subsequently used for ethylene hydroformylation catalysed by the nearby Pt-SiO2 interface. Consequently, propanal was produced selectively from methanol and ethylene on the nanocrystal bilayer tandem catalyst. This new concept of nanocrystal tandem catalysis represents a powerful approach towards designing high-performance, multifunctional nanostructured catalysts

  1. Modulation of enamel matrix proteins on the formation and nano-assembly of hydroxyapatite in vitro

    International Nuclear Information System (INIS)

    Li Hong; Huang Weiya; Zhang Yuanming; Xue Bo; Wen Xuejun

    2012-01-01

    Natural enamel has a hierarchically nanoassembled architecture that is regulated by enamel matrix proteins (EMPs) during the formation of enamel crystals. To understand the role of EMPs on enamel mineralization, calcium phosphate (CaP) growth experiments in both the presence and absence of native rat EMPs in a single diffusion system were conducted. The morphology and organization of formed CaP crystals were examined by X-Ray Diffraction (XRD), High-Resolution Transmission Microscopy (HRTEM) and Selected Area Electron Diffraction (SAED). In the system containing the EMPs, hydroxyapatite (HAP) with hierarchical lamellar nanostructure can be formed and the aligned HAP assembly tightly bundled by 3–4 rod-like nanocrystals like an enamel prism. However, in the absence of EMPs, only a sheet-like structure of octacalcium phosphate (OCP) phase was presented. EMPs promote HAP formation and inhibit the growth of OCP on the (010) plane. It is discussed that the organized Amelogenin/Amorphous Calcium Phosphate might be the precursor to the bundled HAP crystal prism. The study benefits the understanding of biomineralization of tooth enamel. - Highlights: ► An aligned hydroxyapatite crystal bundled by rod-like nanosize crystals was obtained. ► An organized Amel/ACP would be the precursor of the bundled hydroxyapatite crystal prism. ► EMPs inhibit the growth of octacalcium phosphate in a defined plane.

  2. Modulation of enamel matrix proteins on the formation and nano-assembly of hydroxyapatite in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Li Hong, E-mail: tlihong@jnu.edu.cn [Department of Materials Science and Engineering, Jinan University, Guangzhou, Guangdong 510630 (China); Department of Bioengineering, Clemson University, Charleston, SC 29425 (United States); Huang Weiya [Department of Chemistry, Jinan University, Guangzhou, Guangdong 510630 (China); Department of Materials Science and Engineering, Taizhou, Taizhou University, Zhejiang 317000 (China); Zhang Yuanming [Department of Chemistry, Jinan University, Guangzhou, Guangdong 510630 (China); Xue Bo [Department of Materials Science and Engineering, Jinan University, Guangzhou, Guangdong 510630 (China); Wen Xuejun [Department of Bioengineering, Clemson University, Charleston, SC 29425 (United States)

    2012-05-01

    Natural enamel has a hierarchically nanoassembled architecture that is regulated by enamel matrix proteins (EMPs) during the formation of enamel crystals. To understand the role of EMPs on enamel mineralization, calcium phosphate (CaP) growth experiments in both the presence and absence of native rat EMPs in a single diffusion system were conducted. The morphology and organization of formed CaP crystals were examined by X-Ray Diffraction (XRD), High-Resolution Transmission Microscopy (HRTEM) and Selected Area Electron Diffraction (SAED). In the system containing the EMPs, hydroxyapatite (HAP) with hierarchical lamellar nanostructure can be formed and the aligned HAP assembly tightly bundled by 3-4 rod-like nanocrystals like an enamel prism. However, in the absence of EMPs, only a sheet-like structure of octacalcium phosphate (OCP) phase was presented. EMPs promote HAP formation and inhibit the growth of OCP on the (010) plane. It is discussed that the organized Amelogenin/Amorphous Calcium Phosphate might be the precursor to the bundled HAP crystal prism. The study benefits the understanding of biomineralization of tooth enamel. - Highlights: Black-Right-Pointing-Pointer An aligned hydroxyapatite crystal bundled by rod-like nanosize crystals was obtained. Black-Right-Pointing-Pointer An organized Amel/ACP would be the precursor of the bundled hydroxyapatite crystal prism. Black-Right-Pointing-Pointer EMPs inhibit the growth of octacalcium phosphate in a defined plane.

  3. Phase transitions and doping in semiconductor nanocrystals

    Science.gov (United States)

    Sahu, Ayaskanta

    Colloidal semiconductor nanocrystals are a promising technological material because their size-dependent optical and electronic properties can be exploited for a diverse range of applications such as light-emitting diodes, bio-labels, transistors, and solar cells. For many of these applications, electrical current needs to be transported through the devices. However, while their solution processability makes these colloidal nanocrystals attractive candidates for device applications, the bulky surfactants that render these nanocrystals dispersible in common solvents block electrical current. Thus, in order to realize the full potential of colloidal semiconductor nanocrystals in the next-generation of solid-state devices, methods must be devised to make conductive films from these nanocrystals. One way to achieve this would be to add minute amounts of foreign impurity atoms (dopants) to increase their conductivity. Electronic doping in nanocrystals is still very much in its infancy with limited understanding of the underlying mechanisms that govern the doping process. This thesis introduces an innovative synthesis of doped nanocrystals and aims at expanding the fundamental understanding of charge transport in these doped nanocrystal films. The list of semiconductor nanocrystals that can be doped is large, and if one combines that with available dopants, an even larger set of materials with interesting properties and applications can be generated. In addition to doping, another promising route to increase conductivity in nanocrystal films is to use nanocrystals with high ionic conductivities. This thesis also examines this possibility by studying new phases of mixed ionic and electronic conductors at the nanoscale. Such a versatile approach may open new pathways for interesting fundamental research, and also lay the foundation for the creation of novel materials with important applications. In addition to their size-dependence, the intentional incorporation of

  4. Magnetic responsive hydroxyapatite composite scaffolds construction for bone defect reparation.

    Science.gov (United States)

    Zeng, Xiao Bo; Hu, Hao; Xie, Li Qin; Lan, Fang; Jiang, Wen; Wu, Yao; Gu, Zhong Wei

    2012-01-01

    In recent years, interest in magnetic biomimetic scaffolds for tissue engineering has increased considerably. A type of magnetic scaffold composed of magnetic nanoparticles (MNPs) and hydroxyapatite (HA) for bone repair has been developed by our research group. In this study, to investigate the influence of the MNP content (in the scaffolds) on the cell behaviors and the interactions between the magnetic scaffold and the exterior magnetic field, a series of MNP-HA magnetic scaffolds with different MNP contents (from 0.2% to 2%) were fabricated by immersing HA scaffold into MNP colloid. ROS 17/2.8 and MC3T3-E1 cells were cultured on the scaffolds in vitro, with and without an exterior magnetic field, respectively. The cell adhesion, proliferation and differentiation were evaluated via scanning electron microscopy; confocal laser scanning microscopy; and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), alkaline phosphatase, and bone gla protein activity tests. The results demonstrated the positive influence of the magnetic scaffolds on cell adhesion, proliferation, and differentiation. Further, a higher amount of MNPs on the magnetic scaffolds led to more significant stimulation. The magnetic scaffold can respond to the exterior magnetic field and engender some synergistic effect to intensify the stimulating effect of a magnetic field to the proliferation and differentiation of cells.

  5. Biomimetic synthesis and characterization of semiconducting hybrid

    Indian Academy of Sciences (India)

    Triple hybrid materials based on polyaniline-polyethylene glycol and cadmium sulphide have been prepared by the duffusion–limited biomimetic route and characterized by a number of spectroscopic, XRD, SEM, thermal and electrical measurements. These hybrid materials have been prepared by controlled precipitation of ...

  6. Biomimetic micromechanical adaptive flow-sensor arrays

    NARCIS (Netherlands)

    Krijnen, Gijsbertus J.M.; Floris, J.; Dijkstra, Marcel; Lammerink, Theodorus S.J.; Wiegerink, Remco J.

    2007-01-01

    We report current developments in biomimetic flow-sensors based on flow sensitive mechano-sensors of crickets. Crickets have one form of acoustic sensing evolved in the form of mechanoreceptive sensory hairs. These filiform hairs are highly perceptive to low-frequency sound with energy sensitivities

  7. Energy-based and biomimetic robotics

    NARCIS (Netherlands)

    Folkertsma, Gerrit Adriaan

    2017-01-01

    All physical systems interact by exchanging power, or energy. This energy can be explicitly taken into account when designing robotic systems, in dynamic models of systems and controllers, leading to more insight in energy-related effects. In this thesis, a biomimetic cheetah robot is developed, by

  8. In situ synthesis carbonated hydroxyapatite layers on enamel slices with acidic amino acids by a novel two-step method

    International Nuclear Information System (INIS)

    Wu, Xiaoguang; Zhao, Xu; Li, Yi; Yang, Tao; Yan, Xiujuan; Wang, Ke

    2015-01-01

    In situ fabrication of carbonated hydroxyapatite (CHA) remineralization layer on an enamel slice was completed in a novel, biomimetic two-step method. First, a CaCO 3 layer was synthesized on the surface of demineralized enamel using an acidic amino acid (aspartic acid or glutamate acid) as a soft template. Second, at the same concentration of the acidic amino acid, rod-like carbonated hydroxyapatite was produced with the CaCO 3 layer as a sacrificial template and a reactant. The morphology, crystallinity and other physicochemical properties of the crystals were characterized using field emission scanning electron microscopy (FESEM), Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDAX), respectively. Acidic amino acid could promote the uniform deposition of hydroxyapatite with rod-like crystals via absorption of phosphate and carbonate ions from the reaction solution. Moreover, compared with hydroxyapatite crystals coated on the enamel when synthesized by a one-step method, the CaCO 3 coating that was synthesized in the first step acted as an active bridge layer and sacrificial template. It played a vital role in orienting the artificial coating layer through the template effect. The results show that the rod-like carbonated hydroxyapatite crystals grow into bundles, which are similar in size and appearance to prisms in human enamel, when using the two-step method with either aspartic acid or acidic glutamate (20.00 mmol/L). - Graphical abstract: FESEM images of enamel slices etched for 60 s and repaired by the two-step method with Glu concentration of 20.00 mmol/L. (A) The boundary (dotted line) of the repaired areas (b) and unrepaired areas (a). (Some selected areas of etched enamel slices were coated with a nail polish before the reaction, which was removed by acetone after the reaction); (B) high magnification image of Ga, (C) high magnification image of Gb. In situ fabrication of carbonated

  9. In situ synthesis carbonated hydroxyapatite layers on enamel slices with acidic amino acids by a novel two-step method

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Xiaoguang [Department of Pediatric Dentistry, The Hospital of Stomatology, Jilin University, Changchun 130021 (China); Zhao, Xu [College of Chemistry, Jilin University, Changchun 130021 (China); Li, Yi, E-mail: lyi99@jlu.edu.cn [Department of Pediatric Dentistry, The Hospital of Stomatology, Jilin University, Changchun 130021 (China); Yang, Tao [Department of Stomatology, Children' s Hospital of Changchun, 130051 (China); Yan, Xiujuan; Wang, Ke [Department of Pediatric Dentistry, The Hospital of Stomatology, Jilin University, Changchun 130021 (China)

    2015-09-01

    In situ fabrication of carbonated hydroxyapatite (CHA) remineralization layer on an enamel slice was completed in a novel, biomimetic two-step method. First, a CaCO{sub 3} layer was synthesized on the surface of demineralized enamel using an acidic amino acid (aspartic acid or glutamate acid) as a soft template. Second, at the same concentration of the acidic amino acid, rod-like carbonated hydroxyapatite was produced with the CaCO{sub 3} layer as a sacrificial template and a reactant. The morphology, crystallinity and other physicochemical properties of the crystals were characterized using field emission scanning electron microscopy (FESEM), Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDAX), respectively. Acidic amino acid could promote the uniform deposition of hydroxyapatite with rod-like crystals via absorption of phosphate and carbonate ions from the reaction solution. Moreover, compared with hydroxyapatite crystals coated on the enamel when synthesized by a one-step method, the CaCO{sub 3} coating that was synthesized in the first step acted as an active bridge layer and sacrificial template. It played a vital role in orienting the artificial coating layer through the template effect. The results show that the rod-like carbonated hydroxyapatite crystals grow into bundles, which are similar in size and appearance to prisms in human enamel, when using the two-step method with either aspartic acid or acidic glutamate (20.00 mmol/L). - Graphical abstract: FESEM images of enamel slices etched for 60 s and repaired by the two-step method with Glu concentration of 20.00 mmol/L. (A) The boundary (dotted line) of the repaired areas (b) and unrepaired areas (a). (Some selected areas of etched enamel slices were coated with a nail polish before the reaction, which was removed by acetone after the reaction); (B) high magnification image of Ga, (C) high magnification image of Gb. In situ fabrication of

  10. Cementless Hydroxyapatite Coated Hip Prostheses

    Science.gov (United States)

    Herrera, Antonio; Mateo, Jesús; Gil-Albarova, Jorge; Lobo-Escolar, Antonio; Ibarz, Elena; Gabarre, Sergio; Más, Yolanda

    2015-01-01

    More than twenty years ago, hydroxyapatite (HA), calcium phosphate ceramics, was introduced as a coating for cementless hip prostheses. The choice of this ceramic is due to its composition being similar to organic apatite bone crystals. This ceramic is biocompatible, bioactive, and osteoconductive. These qualities facilitate the primary stability and osseointegration of implants. Our surgical experience includes the implantation of more than 4,000 cementless hydroxyapatite coated hip prostheses since 1990. The models implanted are coated with HA in the acetabulum and in the metaphyseal area of the stem. The results corresponding to survival and stability of implants were very satisfactory in the long-term. From our experience, HA-coated hip implants are a reliable alternative which can achieve long term survival, provided that certain requirements are met: good design selection, sound choice of bearing surfaces based on patient life expectancy, meticulous surgical technique, and indications based on adequate bone quality. PMID:25802848

  11. Cementless Hydroxyapatite Coated Hip Prostheses

    Directory of Open Access Journals (Sweden)

    Antonio Herrera

    2015-01-01

    Full Text Available More than twenty years ago, hydroxyapatite (HA, calcium phosphate ceramics, was introduced as a coating for cementless hip prostheses. The choice of this ceramic is due to its composition being similar to organic apatite bone crystals. This ceramic is biocompatible, bioactive, and osteoconductive. These qualities facilitate the primary stability and osseointegration of implants. Our surgical experience includes the implantation of more than 4,000 cementless hydroxyapatite coated hip prostheses since 1990. The models implanted are coated with HA in the acetabulum and in the metaphyseal area of the stem. The results corresponding to survival and stability of implants were very satisfactory in the long-term. From our experience, HA-coated hip implants are a reliable alternative which can achieve long term survival, provided that certain requirements are met: good design selection, sound choice of bearing surfaces based on patient life expectancy, meticulous surgical technique, and indications based on adequate bone quality.

  12. Antimicrobial activity of different hydroxyapatites

    International Nuclear Information System (INIS)

    Feitosa, G.T.; Santos, M.V.B.; Barreto, H.M.; Osorio, L.R.; Osajima, J.A.; Silva Filho, E.C. da

    2014-01-01

    Among the applications of ceramics in the technological context, hydroxyapatite (HAp) stands out in the scientific community due to chemical biocompatibility and molecular similarity to the structures of bone and dental tissues. Such features are added to the antimicrobial properties that this brings. This work aimed at the synthesis of hydroxyapatite by two different routes, hydrothermal (HD HAp) and co-precipitation (CP HAp), as well as verification of the antimicrobial properties of these through direct contact of the powders synthesized tests with Staphylococcus aureus (SA10) and Escherichia coli (EC7) bacteria. The materials was characterized by XRD, Raman and TEM, and Antimicrobial tests showed inhibitory efficacy of 97% and 9.5% of CP HAp for SA10 and EC7, respectively. The HD HAp had inhibitory effect of 95% and 0% for EC7 and SA10, respectively. The inhibitory effect on SA10 is based on the hydrophilicity that the material possesses. (author)

  13. Emission properties of biomimetic composites for dentistry

    Directory of Open Access Journals (Sweden)

    P.V. Seredin

    Full Text Available Biocomposites based on carbonate-substituted hydroxyapatite synthesized from the biological source of calcium (Goloshchapov et al., 2013 and organic primer on the basis of amino acids found in the enamel tubules of teeth, namely, arginine, histidine, lysine and hyaluronic acid were obtained and studied in this work. Incorporation of organic primer into biocomposite formulation allowed us to obtain the emission characteristics (luminescence that were identical to those inherent to the native tissues of the human tooth (enamel and dentine. Keywords: Biocomposites, IR-spectroscopy, Optical and emission properties, Hydroxyapatite, Human tooth tissues

  14. In situ synthesis carbonated hydroxyapatite layers on enamel slices with acidic amino acids by a novel two-step method.

    Science.gov (United States)

    Wu, Xiaoguang; Zhao, Xu; Li, Yi; Yang, Tao; Yan, Xiujuan; Wang, Ke

    2015-09-01

    In situ fabrication of carbonated hydroxyapatite (CHA) remineralization layer on an enamel slice was completed in a novel, biomimetic two-step method. First, a CaCO3 layer was synthesized on the surface of demineralized enamel using an acidic amino acid (aspartic acid or glutamate acid) as a soft template. Second, at the same concentration of the acidic amino acid, rod-like carbonated hydroxyapatite was produced with the CaCO3 layer as a sacrificial template and a reactant. The morphology, crystallinity and other physicochemical properties of the crystals were characterized using field emission scanning electron microscopy (FESEM), Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDAX), respectively. Acidic amino acid could promote the uniform deposition of hydroxyapatite with rod-like crystals via absorption of phosphate and carbonate ions from the reaction solution. Moreover, compared with hydroxyapatite crystals coated on the enamel when synthesized by a one-step method, the CaCO3 coating that was synthesized in the first step acted as an active bridge layer and sacrificial template. It played a vital role in orienting the artificial coating layer through the template effect. The results show that the rod-like carbonated hydroxyapatite crystals grow into bundles, which are similar in size and appearance to prisms in human enamel, when using the two-step method with either aspartic acid or acidic glutamate (20.00 mmol/L). Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Fabrication of nanocrystalline hydroxyapatite doped degradable composite hollow fiber for guided and biomimetic bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Ning [Department of Bioengineering, Clemson University, Clemson, SC, 29634 (United States); Nichols, Heather L. [Department of Bioengineering, Clemson University, Clemson, SC, 29634 (United States); Tylor, Shila [Department of Bioengineering, Clemson University, Clemson, SC, 29634 (United States); Wen Xuejun [Department of Bioengineering, Clemson University, Clemson, SC, 29634 (United States)]. E-mail: xjwen@clemson.edu

    2007-04-15

    Natural bone tissue possesses a nanocomposite structure interwoven in a three-dimensional (3-D) matrix, which plays critical roles in conferring appropriate physical and biological properties to the bone tissue. Single type of material may not be sufficient to mimic the composition, structure and properties of native bone, therefore, composite materials consisting of both polymers, bioceramics, and other inorganic materials have to be designed. Among a variety of candidate materials, polymer-nanoparticle composites appear most promising for bone tissue engineering applications because of superior mechanical properties, improved durability, and surface bioactivity when compared with conventional polymers or composites. The long term objective of this project is to use highly aligned, bioactive, biodegradable scaffold mimicking natural histological structure of human long bone, and to engineer and regenerate human long bone both in vitro and in vivo. In this study, bioactive, degradable, and highly permeable composite hollow fiber membranes (HFMs) were fabricated using a wet phase phase-inversion approach. The structure of the hollow fiber membranes was examined using scanning electron microscopy (SEM); degradation behavior was examined using weigh loss assay, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC); and bioactivity was evaluated with the amount of calcium deposition from the culture media onto HFM surface. Doping PLGA HFMs with nanoHA results in a more bioactive and slower degrading HFM than pure PLGA HFMs.

  16. Biomimetic Deposition of Hydroxyapatite by Mixed Acid Treatment of Titanium Surfaces.

    Science.gov (United States)

    Zhao, J M; Park, W U; Hwang, K H; Lee, J K; Yoon, S Y

    2015-03-01

    A simple chemical method was established for inducing bioactivity of Ti metal. In the present study, two kinds of mixed acid solutions were used to treat Ti specimens to induce Ca-P formation. Following a strong mixed acid activation process, Ca-P coatings successfully formed on the Ti surfaces in the simulated body fluid. Strong mixed acid etching was used to increase the roughness of the metal surface, because the porous and rough surfaces allow better adhesion between Ca-P coatings and substrate. Nano-scale modification of titanium surfaces can alter cellular and tissue responses, which may benefit osseointegration and dental implant therapy. Some specimens were treated with a 5 M NaOH aqueous solution, and then heat treated at 600 °C in order to form an amorphous sodium titanate layer on their surface. This treated titanium metal is believed to form a dense and uniform bone-like apatite layer on its surface in a simulated body fluid (SBF). This study proved that mixed acid treatment is not only important for surface passivation but is also another bioactive treatment for titanium surfaces, an alternative to alkali treatment. In addition, mixed acid treatment uses a lower temperature and shorter time period than alkali treatment.

  17. Structure Map for Embedded Binary Alloy Nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, C.W.; Shin, S.J.; Liao, C.Y.; Guzman, J.; Stone, P.R.; Watanabe, M.; Ager III, J.W.; Haller, E.E.; Chrzan, D.C.

    2008-09-20

    The equilibrium structure of embedded nanocrystals formed from strongly segregating binary-alloys is considered within a simple thermodynamic model. The model identifies two dimensionlessinterface energies that dictate the structure, and allows prediction of the stable structure for anychoice of these parameters. The resulting structure map includes three distinct nanocrystal mor-phologies: core/shell, lobe/lobe, and completely separated spheres.

  18. Hollow nanocrystals and method of making

    Science.gov (United States)

    Alivisatos, A Paul [Oakland, CA; Yin, Yadong [Moreno Valley, CA; Erdonmez, Can Kerem [Berkeley, CA

    2011-07-05

    Described herein are hollow nanocrystals having various shapes that can be produced by a simple chemical process. The hollow nanocrystals described herein may have a shell as thin as 0.5 nm and outside diameters that can be controlled by the process of making.

  19. Synthesis, spectroscopy and simulation of doped nanocrystals

    NARCIS (Netherlands)

    Suyver, Jan Frederik

    2003-01-01

    This thesis deals with the properties of semiconductor nanocrystals (ZnS or ZnSe) in the size range (diameter) of 2 nm to 10 nm. The nanocrystals under investigation are doped with the transition metal ions manganese or copper. The goal is to study photoluminescence and electroluminescence from

  20. Electronic displays using optically pumped luminescent semiconductor nanocrystals

    Science.gov (United States)

    Weiss, Shimon [Pinole, CA; Schlamp, Michael C [Plainsboro, NJ; Alivisatos, A Paul [Oakland, CA

    2011-09-27

    A multicolor electronic display is based on an array of luminescent semiconductor nanocrystals. Nanocrystals which emit light of different colors are grouped into pixels. The nanocrystals are optically pumped to produce a multicolor display. Different sized nanocrystals are used to produce the different colors. A variety of pixel addressing systems can be used.

  1. In situ annealing of hydroxyapatite thin films

    International Nuclear Information System (INIS)

    Johnson, Shevon; Haluska, Michael; Narayan, Roger J.; Snyder, Robert L.

    2006-01-01

    Hydroxyapatite is a bioactive ceramic that mimics the mineral composition of natural bone. Unfortunately, problems with adhesion, poor mechanical integrity, and incomplete bone ingrowth limit the use of many conventional hydroxyapatite surfaces. In this work, we have developed a novel technique to produce crystalline hydroxyapatite thin films involving pulsed laser deposition and postdeposition annealing. Hydroxyapatite films were deposited on Ti-6Al-4V alloy and Si (100) using pulsed laser deposition, and annealed within a high temperature X-ray diffraction system. The transformation from amorphous to crystalline hydroxyapatite was observed at 340 deg. C. Mechanical and adhesive properties were examined using nanoindentation and scratch adhesion testing, respectively. Nanohardness and Young's modulus values of 3.48 and 91.24 GPa were realized in unannealed hydroxyapatite films. Unannealed and 350 deg. C annealed hydroxyapatite films exhibited excellent adhesion to Ti-6Al-4V alloy substrates. We anticipate that the adhesion and biological properties of crystalline hydroxyapatite thin films may be enhanced by further consideration of deposition and annealing parameters

  2. Characteristics of porous zirconia coated with hydroxyapatite

    Indian Academy of Sciences (India)

    However, porous hydroxyapatite bodies are mechanically weak and brittle, which makes shaping and implantation difficult. One way to solve this problem is to introduce a strong porous network onto which hydroxyapatite coating is applied. In this study, porous zirconia and alumina-added zirconia ceramics were prepared ...

  3. In situ biomimetic synthesis, characterization and in vitro investigation of bone-like nanohydroxyapatite in starch matrix

    Energy Technology Data Exchange (ETDEWEB)

    Sadjadi, M.S., E-mail: msadjad@gmail.com [Department of Chemistry, Science and Research Branch, Islamic Azad University, Poonak, Tehran (Iran, Islamic Republic of); Meskinfam, M. [Department of Chemistry, Science and Research Branch, Islamic Azad University, Poonak, Tehran (Iran, Islamic Republic of); Sadeghi, B. [Department of Chemistry, Tonekabon Branch, Islamic Azad university, Tonekabon (Iran, Islamic Republic of); Jazdarreh, H. [Department of Mechanical Engineering, Iran University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of); Zare, K. [Department of Chemistry, Faculty of Science, Shahid Beheshti University, Tehran (Iran, Islamic Republic of)

    2010-11-01

    In this work, we report the synthesis of bone-like hydroxyapatite (HAp) nanorods in wheat starch matrix via a biomimetic process. Characterization of the samples was performed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Scanning and transmission electron microscopy (SEM and TEM) were used to determine the size, shape and morphology of nano-HAp. The results indicate that, the shape and morphology of nHAp is influenced by the presence of starch as a template agent and rod-like nHAp similar to the inorganic component in the human body is obtained at room temperature. In vitro bioactivity of the synthesized HAp nanocomposites was finally verified by comparison of the HAp's structures and morphology before and after immersion in simulated body fluid (SBF) solution for 3, 7, and 14 days.

  4. In vitro deposition of hydroxyapatite on cortical bone collagen stimulated by deformation-induced piezoelectricity.

    Science.gov (United States)

    Noris-Suárez, Karem; Lira-Olivares, Joaquin; Ferreira, Ana Marina; Feijoo, José Luis; Suárez, Nery; Hernández, Maria C; Barrios, Esteban

    2007-03-01

    In the present work, we have studied the effect of the piezoelectricity of elastically deformed cortical bone collagen on surface using a biomimetic approach. The mineralization process induced as a consequence of the piezoelectricity effect was evaluated using scanning electron microscopy (SEM), thermally stimulated depolarization current (TSDC), and differential scanning calorimetry (DSC). SEM micrographs showed that mineralization occurred predominantly over the compressed side of bone collagen, due to the effect of piezoelectricity, when the sample was immersed in the simulated body fluid (SBF) in a cell-free system. The TSDC method was used to examine the complex collagen dielectric response. The dielectric spectra of deformed and undeformed collagen samples with different hydration levels were compared and correlated with the mineralization process followed by SEM. The dielectric measurements showed that the mineralization induced significant changes in the dielectric spectra of the deformed sample. DSC and TSDC results demonstrated a reduction of the collagen glass transition as the mineralization process advanced. The combined use of SEM, TSDC, and DSC showed that, even without osteoblasts present, the piezoelectric dipoles produced by deformed collagen can produce the precipitation of hydroxyapatite by electrochemical means, without a catalytic converter as occurs in classical biomimetic deposition.

  5. Synthesis spherical porous hydroxyapatite/graphene oxide composites by ultrasonic-assisted method for biomedical applications.

    Science.gov (United States)

    Duan, Peizhen; Shen, Juan; Zou, Guohong; Xia, Xu; Jin, Bo; Yu, Jiaxin

    2018-04-10

    Spherical porous hydroxyapatite (SHA)/graphene oxide (GO) composites with different GO (w/w) content of 16%, 40%, and 71% have been fabricated through a facile and controllable ultrasonic-assisted method at room temperature. The products were characterized by x-ray diffraction, field emission scanning electron microscopy, thermogravimetric analysis, mechanical testing and biomimetic mineralization. Results showed SHA were covered by GO, and SHA/GO composites had an irregular surface with different degrees of wrinkles. The elastic modulus and hardness of SHA/GO-3 composites were up to 12.45 ± 0.33 GPa and 686.67 ± 26.95 MPa, which indicated that the contents of GO had an effect on SHA/GO composites. And the mechanical properties of SHA/GO-2 composites were similar to SHA particles. The biomimetic mineralization in SBF solution showed the bone-like apatite layer on composites surface, which demonstrated that the SHA/GO materials had osseointegration property. Moreover, in vitro cytocompatibility of SHA/GO-2 composites and pure GO were evaluated by cell adhesion and proliferation tests using MC3T3-E1 cells, which demonstrated that the SHA/GO composites can act as a good template for the cells growth and adhesion. These results suggested that the SHA/GO composites will be a promising material for biomedical application.

  6. Factors influencing the deposition of hydroxyapatite coating onto hollow glass microspheres

    International Nuclear Information System (INIS)

    Jiao, Yan; Xiao, Gui-Yong; Xu, Wen-Hua; Zhu, Rui-Fu; Lu, Yu-Peng

    2013-01-01

    Hydroxyapatite (HA) and HA coated microcarriers for cell culture and delivery have attracted more attention recently, owing to the rapid progress in the field of tissue engineering. In this research, a dense and uniform HA coating with the thickness of about 2 μm was successfully deposited on hollow glass microspheres (HGM) by biomimetic process. The influences of SBF concentration, immersion time, solid/liquid ratio and activation of HGM on the deposition rate and coating characteristics were discussed. X-ray diffraction (XRD) and Fourier transform infrared spectrum (FTIR) analyses revealed that the deposited HA is poorly crystalline. The thickness of HA coating showed almost no increase after immersion in 1.5SBF for more than 15 days with the solid/liquid ratio of 1:150. At the same time, SBF concentration, solid/liquid ratio and activation treatment played vital roles in the formation of HA coating on HGM. This poorly crystallized HA coated HGM could have potential use as microcarrier for cell culture. Highlights: • HA coatings were deposited on hollow glass microspheres by biomimetic process. • The obtained HA coating was poorly crystalline and carbonated. • The influencing factors of deposition rate and coating characteristics were studied. • The thickness of HA coating showed almost no increase after immersion for 15 days

  7. Symmetry breaking during seeded growth of nanocrystals.

    Science.gov (United States)

    Xia, Xiaohu; Xia, Younan

    2012-11-14

    Currently, most of the reported noble-metal nanocrystals are limited to a high level of symmetry, as constrained by the inherent, face-centered cubic (fcc) lattice of these metals. In this paper, we report, for the first time, a facile and versatile approach (backed up by a clear mechanistic understanding) for breaking the symmetry of an fcc lattice and thus obtaining nanocrystals with highly unsymmetrical shapes. The key strategy is to induce and direct the growth of nanocrystal seeds into unsymmetrical modes by manipulating the reduction kinetics. With silver as an example, we demonstrated that the diversity of possible shapes taken by noble-metal nanocrystals could be greatly expanded by incorporating a series of new shapes drastically deviated from the fcc lattice. This work provides a new method to investigate shape-controlled synthesis of metal nanocrystal.

  8. Measuring the Valence of Nanocrystal Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Owen, Jonathan Scharle [Columbia Univ., New York, NY (United States)

    2016-11-30

    The goal of this project is to understand and control the interplay between nanocrystal stoichiometry, surface ligand binding and exchange, and the optoelectronic properties of semiconductor nanocrystals in solution and in thin solid films. We pursued three research directions with this goal in mind: 1) We characterized nanocrystal stoichiometry and its influence on the binding of L-type and X-type ligands, including the thermodynamics of binding and the kinetics of ligand exchange. 2) We developed a quantitative understanding of the relationship between surface ligand passivation and photoluminescence quantum yield. 3) We developed methods to replace the organic ligands on the nanocrystal with halide ligands and controllably deposit these nanocrystals into thin films, where electrical measurements were used to investigate the electrical transport and internanocrystal electronic coupling.

  9. Robust High Performance Aquaporin based Biomimetic Membranes

    DEFF Research Database (Denmark)

    Helix Nielsen, Claus; Zhao, Yichun; Qiu, C.

    2013-01-01

    on top of a support membrane. Control membranes, either without aquaporins or with the inactive AqpZ R189A mutant aquaporin served as controls. The separation performance of the membranes was evaluated by cross-flow forward osmosis (FO) and reverse osmosis (RO) tests. In RO the ABM achieved a water......Aquaporins are water channel proteins with high water permeability and solute rejection, which makes them promising for preparing high-performance biomimetic membranes. Despite the growing interest in aquaporin-based biomimetic membranes (ABMs), it is challenging to produce robust and defect...... permeability of ~ 4 L/(m2 h bar) with a NaCl rejection > 97% at an applied hydraulic pressure of 5 bar. The water permeability was ~40% higher compared to a commercial brackish water RO membrane (BW30) and an order of magnitude higher compared to a seawater RO membrane (SW30HR). In FO, the ABMs had > 90...

  10. Major Intrinsic Proteins in Biomimetic Membranes

    DEFF Research Database (Denmark)

    Helix Nielsen, Claus

    2010-01-01

    or as sensor devices based on e.g., the selective permeation of metalloids. In principle a MIP based membrane sensor/separation device requires the supporting biomimetic matrix to be virtually impermeable to anything but water or the solute in question. In practice, however, a biomimetic support matrix....../separation technology, a unique class of membrane transport proteins is especially interesting the major intrinsic proteins (MIPs). Generally, MIPs conduct water molecules and selected solutes in and out of the cell while preventing the passage of other solutes, a property critical for the conservation of the cells...... internal pH and salt concentration. Also known as water channels or aquaporins they are highly efficient membrane pore proteins some of which are capable of transporting water at very high rates up to 109 molecules per second. Some MIPs transport other small, uncharged solutes, such as glycerol and other...

  11. The state of the art in biomimetics.

    Science.gov (United States)

    Lepora, Nathan F; Verschure, Paul; Prescott, Tony J

    2013-03-01

    Biomimetics is a research field that is achieving particular prominence through an explosion of new discoveries in biology and engineering. The field concerns novel technologies developed through the transfer of function from biological systems. To analyze the impact of this field within engineering and related sciences, we compiled an extensive database of publications for study with network-based information analysis techniques. Criteria included publications by year and journal or conference, and subject areas judged by popular and common terms in titles. Our results reveal that this research area has expanded rapidly from less than 100 papers per year in the 1990s to several thousand papers per year in the first decade of this century. Moreover, this research is having impact across a variety of research themes, spanning robotics, computer science and bioengineering. In consequence, biomimetics is becoming a leading paradigm for the development of new technologies that will potentially lead to significant scientific, societal and economic impact in the near future.

  12. Green Tribology Biomimetics, Energy Conservation and Sustainability

    CERN Document Server

    Bhushan, Bharat

    2012-01-01

    Tribology is the study of friction, wear and lubrication. Recently, the concept of “green tribology” as “the science and technology of the tribological aspects of ecological balance and of environmental and biological impacts” was introduced. The field of green tribology includes tribological technology that mimics living nature (biomimetic surfaces) and thus is expected to be environmentally friendly, the control of friction and wear that is of importance for energy conservation and conversion, environmental aspects of lubrication and surface modification techniques, and tribological aspects of green applications such as wind-power turbines or solar panels. This book is the first comprehensive volume on green tribology. The chapters are prepared by leading experts in their fields and cover such topics as biomimetics, environmentally friendly lubrication, tribology of wind turbines and renewable sources of energy, and ecological impact of new technologies of surface treatment.

  13. Biologically inspired rosette nanotubes and nanocrystalline hydroxyapatite hydrogel nanocomposites as improved bone substitutes

    International Nuclear Information System (INIS)

    Zhang Lijie; Webster, Thomas J; Rodriguez, Jose; Raez, Jose; Myles, Andrew J; Fenniri, Hicham

    2009-01-01

    Today, bone diseases such as bone fractures, osteoporosis and bone cancer represent a common and significant public health problem. The design of biomimetic bone tissue engineering materials that could restore and improve damaged bone tissues provides exciting opportunities to solve the numerous problems associated with traditional orthopedic implants. Therefore, the objective of this in vitro study was to create a biomimetic orthopedic hydrogel nanocomposite based on the self-assembly properties of helical rosette nanotubes (HRNs), the osteoconductive properties of nanocrystalline hydroxyapatite (HA), and the biocompatible properties of hydrogels (specifically, poly(2-hydroxyethyl methacrylate), pHEMA). HRNs are self-assembled nanomaterials that are formed from synthetic DNA base analogs in water to mimic the helical nanostructure of collagen in bone. In this study, different geometries of nanocrystalline HA were controlled by either hydrothermal or sintering methods. 2 and 10 wt% nanocrystalline HA particles were well dispersed into HRN hydrogels using ultrasonication. The nanocrystalline HA and nanocrystalline HA/HRN hydrogels were characterized by x-ray diffraction, transmission electron microscopy, and scanning electron microscopy. Mechanical testing studies revealed that the well dispersed nanocrystalline HA in HRN hydrogels possessed improved mechanical properties compared to hydrogel controls. In addition, the results of this study provided the first evidence that the combination of either 2 or 10 wt% nanocrystalline HA and 0.01 mg ml -1 HRNs in hydrogels greatly increased osteoblast (bone-forming cell) adhesion up to 236% compared to hydrogel controls. Moreover, this study showed that HRNs stimulated HA nucleation and mineralization along their main axis in a way that is very reminiscent of the HA/collagen assembly pattern in natural bone. In summary, the presently observed excellent properties of the biomimetic nanocrystalline HA/HRN hydrogel composites

  14. Strontium hydroxyapatite/chitosan nanohybrid scaffolds with enhanced osteoinductivity for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Yong [The Education Ministry Key Lab of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai 200234 (China); Xu, Zhengliang [Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People' s Hospital, 600 Yishan Road, Shanghai 200233 (China); Ke, Qinfei [The Education Ministry Key Lab of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai 200234 (China); Yin, Wenjing; Chen, Yixuan [Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People' s Hospital, 600 Yishan Road, Shanghai 200233 (China); Zhang, Changqing, E-mail: zhangcq@sjtu.edu.cn [Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People' s Hospital, 600 Yishan Road, Shanghai 200233 (China); Guo, Yaping, E-mail: ypguo@shnu.edu.cn [The Education Ministry Key Lab of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai 200234 (China)

    2017-03-01

    For the clinical application of bone tissue engineering with the combination of biomaterials and mesenchymal stem cells (MSCs), bone scaffolds should possess excellent biocompatibility and osteoinductivity to accelerate the repair of bone defects. Herein, strontium hydroxyapatite [SrHAP, Ca{sub 10−x}Sr{sub x}(PO{sub 4}){sub 6}(OH){sub 2}]/chitosan (CS) nanohybrid scaffolds were fabricated by a freeze-drying method. The SrHAP nanocrystals with the different x values of 0, 1, 5 and 10 are abbreviated to HAP, Sr1HAP, Sr5HAP and Sr10HAP, respectively. With increasing x values from 0 to 10, the crystal cell volumes and axial lengths of SrHAP become gradually large because of the greater ion radius of Sr{sup 2+} than Ca{sup 2+}, while the crystal sizes of SrHAP decrease from 70.4 nm to 46.7 nm. The SrHAP/CS nanohybrid scaffolds exhibits three-dimensional (3D) interconnected macropores with pore sizes of 100–400 μm, and the SrHAP nanocrystals are uniformly dispersed within the scaffolds. In vitro cell experiments reveal that all the HAP/CS, Sr1HAP/CS, Sr5HAP/CS and Sr10HAP/CS nanohybrid scaffolds possess excellent cytocompatibility with the favorable adhesion, spreading and proliferation of human bone marrow mesenchymal stem cells (hBMSCs). The Sr5HAP nanocrystals in the scaffolds do not affect the adhesion, spreading of hBMSCs, but they contribute remarkably to cell proliferation and osteogenic differentiation. As compared with the HAP/CS nanohybrid scaffold, the released Sr{sup 2+} ions from the SrHAP/CS nanohybrid scaffolds enhance alkaline phosphatase (ALP) activity, extracellular matrix (ECM) mineralization and osteogenic-related COL-1 and ALP expression levels. Especially, the Sr5HAP/CS nanohybrid scaffolds exhibit the best osteoinductivity among four groups because of the synergetic effect between Ca{sup 2+} and Sr{sup 2+} ions. Hence, the Sr5HAP/CS nanohybrid scaffolds with excellent cytocompatibility and osteogenic property have promising application for

  15. Strontium hydroxyapatite/chitosan nanohybrid scaffolds with enhanced osteoinductivity for bone tissue engineering

    International Nuclear Information System (INIS)

    Lei, Yong; Xu, Zhengliang; Ke, Qinfei; Yin, Wenjing; Chen, Yixuan; Zhang, Changqing; Guo, Yaping

    2017-01-01

    For the clinical application of bone tissue engineering with the combination of biomaterials and mesenchymal stem cells (MSCs), bone scaffolds should possess excellent biocompatibility and osteoinductivity to accelerate the repair of bone defects. Herein, strontium hydroxyapatite [SrHAP, Ca 10−x Sr x (PO 4 ) 6 (OH) 2 ]/chitosan (CS) nanohybrid scaffolds were fabricated by a freeze-drying method. The SrHAP nanocrystals with the different x values of 0, 1, 5 and 10 are abbreviated to HAP, Sr1HAP, Sr5HAP and Sr10HAP, respectively. With increasing x values from 0 to 10, the crystal cell volumes and axial lengths of SrHAP become gradually large because of the greater ion radius of Sr 2+ than Ca 2+ , while the crystal sizes of SrHAP decrease from 70.4 nm to 46.7 nm. The SrHAP/CS nanohybrid scaffolds exhibits three-dimensional (3D) interconnected macropores with pore sizes of 100–400 μm, and the SrHAP nanocrystals are uniformly dispersed within the scaffolds. In vitro cell experiments reveal that all the HAP/CS, Sr1HAP/CS, Sr5HAP/CS and Sr10HAP/CS nanohybrid scaffolds possess excellent cytocompatibility with the favorable adhesion, spreading and proliferation of human bone marrow mesenchymal stem cells (hBMSCs). The Sr5HAP nanocrystals in the scaffolds do not affect the adhesion, spreading of hBMSCs, but they contribute remarkably to cell proliferation and osteogenic differentiation. As compared with the HAP/CS nanohybrid scaffold, the released Sr 2+ ions from the SrHAP/CS nanohybrid scaffolds enhance alkaline phosphatase (ALP) activity, extracellular matrix (ECM) mineralization and osteogenic-related COL-1 and ALP expression levels. Especially, the Sr5HAP/CS nanohybrid scaffolds exhibit the best osteoinductivity among four groups because of the synergetic effect between Ca 2+ and Sr 2+ ions. Hence, the Sr5HAP/CS nanohybrid scaffolds with excellent cytocompatibility and osteogenic property have promising application for bone tissue engineering. - Highlights: • We

  16. Biomimetic syntheses of phenols from polyketones.

    Science.gov (United States)

    Evans, G E; Garson, M J; Griffin, D A; Leeper, F J; Stauton, J

    1978-01-01

    As a result of speculation that many enzymes control polyketone cyclization in vivo by converting a key carbonyl group to a cis-enol ether derivative, we describe two novel biomimetic cyclizations. The first involves condensation of two C6 units derived from triacetic lactone to form an arylpyrone related to aloenin. In the second a naphthapyrone of the rubrofusarin type is formed by condensation of an orsellinic acid derivative with the ether of triacetic lactone.

  17. Biopolymers/poly(ε-caprolactone)/polyethylenimine functionalized nano-hydroxyapatite hybrid cryogel: Synthesis, characterization and application in gene delivery.

    Science.gov (United States)

    Simionescu, Bogdan C; Drobota, Mioara; Timpu, Daniel; Vasiliu, Tudor; Constantinescu, Cristina Ana; Rebleanu, Daniela; Calin, Manuela; David, Geta

    2017-12-01

    Nano-hydroxyapatite (nHAp), surface functionalized with linear polyethylenimine (LPEI), was used for the preparation of biocomposites in combination with biopolymers and poly(ε-caprolactone) (PCL), by cryogelation technique, to yield biomimetic scaffolds with controlled interconnected macroporosity, mechanical stability, and predictable degradation behavior. The structural characteristics, swelling and degradation behavior of hydroxyapatite and hydroxyapatite/β-tricalcium phosphate (β-TCP) filled matrices were investigated as compared to the corresponding naked polymer 3D system. It was found that the homogeneity and cohesivity of the composite are significantly dependent on the size and amount of the included inorganic particles, which are thus determining the structural parameters. Surface modification with LPEI and nanodimensions favored the nHAp integration in the organic matrix, with preferential location along protein fibers, while β-TCP microparticles induced an increased disorder in the hybrid system. The biocomposite including nHAp only was further investigated targeting biomedical uses, and proved to be non-cytotoxic and capable of acting as gene-activated matrix (GAM). It allowed sustained delivery over time (until 22days) of embedded PEI 25 -pDNA polyplexes at high levels of transgene expression, while insuring a decrease in cytotoxicity as compared to polyplexes alone. Experimental data recommend such biocomposite as an attractive material for regenerative medicine. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Biomimetic nanoparticles: preparation, characterization and biomedical applications

    Directory of Open Access Journals (Sweden)

    Ana Maria Carmona-Ribeiro

    2010-04-01

    Full Text Available Ana Maria Carmona-RibeiroBiocolloids Lab, Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, BrazilAbstract: Mimicking nature is a powerful approach for developing novel lipid-based devices for drug and vaccine delivery. In this review, biomimetic assemblies based on natural or synthetic lipids by themselves or associated to silica, latex or drug particles will be discussed. In water, self-assembly of lipid molecules into supramolecular structures is fairly well understood. However, their self-assembly on a solid surface or at an interface remains poorly understood. In certain cases, hydrophobic drug granules can be dispersed in aqueous solution via lipid adsorption surrounding the drug particles as nanocapsules. In other instances, hydrophobic drug molecules attach as monomers to borders of lipid bilayer fragments providing drug formulations that are effective in vivo at low drug-to-lipid-molar ratio. Cationic biomimetic particles offer suitable interfacial environment for adsorption, presentation and targeting of biomolecules in vivo. Thereby antigens can effectively be presented by tailored biomimetic particles for development of vaccines over a range of defined and controllable particle sizes. Biomolecular recognition between receptor and ligand can be reconstituted by means of receptor immobilization into supported lipidic bilayers allowing isolation and characterization of signal transduction steps.Keywords: cationic lipid, phospholipids, bilayer fragments, vesicles, silica, polymeric particles, antigens, novel cationic immunoadjuvants, drugs

  19. Minocycline-released hydroxyapatite-gelatin nanocomposite and its cytocompatibility in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Dou Xiaochen; Zhu Xiaopeng; Zhou Jian; Cai Huaqiong; Li Quanli [Key Laboratory of Oral Disease Research of Anhui Province, Stomatologic Hospital and Collage, Anhui Medical University, Hefei (China); Tang Jian, E-mail: ql-li@126.com [Department of Orthopedic Surgery, The First Hospital of Anhui Medical University, Hefei (China)

    2011-04-15

    The incorporation of antibacterial agents into biomaterials is extremely desirable for repairing bone defects. Minocycline, a semi-synthetic tetracycline antibiotic, is active against aerobic, anaerobic, Gram-positive and Gram-negative bacteria, and can enhance bone formation, decrease connective tissue breakdown and diminish bone resorption. In this study, a novel minocycline-releasing biomaterial was synthesized using a biomimetic method. A measured amount of an acidic hydroxyapatite and minocycline solution was respectively added to a gelatin solution and kept at 40 deg. C and pH 7-8 for 2 h. The mixture was aged overnight, lyophilized and a hydroxyapatite-gelatin-minocycline composite was obtained. The composite was co-cultured with rat bone marrow stromal cells (BMSCs) in vitro. Our results show that nanohydroxyapatite was distributed evenly in the fibrils of the gelatin. Minocycline was incorporated into the composite and could be released from the composite particles slowly over 2 weeks in vitro. The composite promoted BMSC adhesion, proliferation and differentiation in vitro. The approach described here may provide a basis for the preparation of an antibacterial biomaterial for bone regeneration.

  20. Minocycline-released hydroxyapatite-gelatin nanocomposite and its cytocompatibility in vitro

    International Nuclear Information System (INIS)

    Dou Xiaochen; Zhu Xiaopeng; Zhou Jian; Cai Huaqiong; Li Quanli; Tang Jian

    2011-01-01

    The incorporation of antibacterial agents into biomaterials is extremely desirable for repairing bone defects. Minocycline, a semi-synthetic tetracycline antibiotic, is active against aerobic, anaerobic, Gram-positive and Gram-negative bacteria, and can enhance bone formation, decrease connective tissue breakdown and diminish bone resorption. In this study, a novel minocycline-releasing biomaterial was synthesized using a biomimetic method. A measured amount of an acidic hydroxyapatite and minocycline solution was respectively added to a gelatin solution and kept at 40 deg. C and pH 7-8 for 2 h. The mixture was aged overnight, lyophilized and a hydroxyapatite-gelatin-minocycline composite was obtained. The composite was co-cultured with rat bone marrow stromal cells (BMSCs) in vitro. Our results show that nanohydroxyapatite was distributed evenly in the fibrils of the gelatin. Minocycline was incorporated into the composite and could be released from the composite particles slowly over 2 weeks in vitro. The composite promoted BMSC adhesion, proliferation and differentiation in vitro. The approach described here may provide a basis for the preparation of an antibacterial biomaterial for bone regeneration.

  1. Biomimetic Nanohydroxyapatite Synthesized With/Without Tris-Buffered Simulated Body Fluid: A Comparative Analysis.

    Science.gov (United States)

    Rana, Deepti; Wang, Xiumei; Webster, Thomas J; Ramalingam, Murugan

    2018-06-01

    Nano hydroxyapatite (nHAp) mimics the inorganic phase of hard tissue such as bone and teeth and, thus, has a wide range of clinical applications. The present study reports on the biomimetic synthesis of nHAp with and without Tris-buffered simulated body fluid (SBF) and investigated the role of buffering conditions on nHAp formation. The hypothesis of this study was that the nucleation and growth rate of nHAp may depend on buffering conditions during the precipitation process. The results of this study suggest that both of the above methods effectively synthesized carbonated "bone-like" nHAp. However, an increased incubation period of 8 hrs was necessary for nHAp synthesized using non Tris-buffered SBF as compared to Tris-buffered SBF which synthesized nHAp in just 3 hrs. Interestingly, there was no change in the chemical functionality for both samples. XRD and TGA analysis confirmed that Tris-buffered SBF facilitated more carbonate ion substitution than the non-Tris-buffered SBF approach. Therefore, this study concluded for the first time that the addition of Tris in SBF accelerates nHAp formation with more carbonate ion substitution. Nevertheless, carbonate ion substituted nHAp could also be synthesized using non Tris-buffered SBF, but would require longer incubation periods. This analysis highlights the importance of pH stability in the SBF for biomimetic nHAp synthesis which is useful for the synthesis of nHAp for a wide range of biomedical applications.

  2. Biomimetic composite coating on rapid prototyped scaffolds for bone tissue engineering.

    Science.gov (United States)

    Arafat, M Tarik; Lam, Christopher X F; Ekaputra, Andrew K; Wong, Siew Yee; Li, Xu; Gibson, Ian

    2011-02-01

    The objective of this present study was to improve the functional performance of rapid prototyped scaffolds for bone tissue engineering through biomimetic composite coating. Rapid prototyped poly(ε-caprolactone)/tri-calcium phosphate (PCL/TCP) scaffolds were fabricated using the screw extrusion system (SES). The fabricated PCL/TCP scaffolds were coated with a carbonated hydroxyapatite (CHA)-gelatin composite via biomimetic co-precipitation. The structure of the prepared CHA-gelatin composite coating was studied by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Compressive mechanical testing revealed that the coating process did not have any detrimental effect on the mechanical properties of the scaffolds. The cell-scaffold interaction was studied by culturing porcine bone marrow stromal cells (BMSCs) on the scaffolds and assessing the proliferation and bone-related gene and protein expression capabilities of the cells. Confocal laser microscopy and SEM images of the cell-scaffold constructs showed a uniformly distributed cell sheet and accumulation of extracellular matrix in the interior of CHA-gelatin composite-coated PCL/TCP scaffolds. The proliferation rate of BMSCs on CHA-gelatin composite-coated PCL/TCP scaffolds was about 2.3 and 1.7 times higher than that on PCL/TCP scaffolds and CHA-coated PCL/TCP scaffolds, respectively, by day 10. Furthermore, reverse transcription polymerase chain reaction and Western blot analysis revealed that CHA-gelatin composite-coated PCL/TCP scaffolds stimulate osteogenic differentiation of BMSCs the most, compared with PCL/TCP scaffolds and CHA-coated PCL/TCP scaffolds. These results demonstrate that CHA-gelatin composite-coated rapid prototyped PCL/TCP scaffolds are promising for bone tissue engineering. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  3. Biomimetics of human movement: functional or aesthetic?

    International Nuclear Information System (INIS)

    Harris, Christopher M

    2009-01-01

    How should robotic or prosthetic arms be programmed to move? Copying human smooth movements is popular in synthetic systems, but what does this really achieve? We cannot address these biomimetic issues without a deep understanding of why natural movements are so stereotyped. In this article, we distinguish between 'functional' and 'aesthetic' biomimetics. Functional biomimetics requires insight into the problem that nature has solved and recognition that a similar problem exists in the synthetic system. In aesthetic biomimetics, nature is copied for its own sake and no insight is needed. We examine the popular minimum jerk (MJ) model that has often been used to generate smooth human-like point-to-point movements in synthetic arms. The MJ model was originally justified as maximizing 'smoothness'; however, it is also the limiting optimal trajectory for a wide range of cost functions for brief movements, including the minimum variance (MV) model, where smoothness is a by-product of optimizing the speed-accuracy trade-off imposed by proportional noise (PN: signal-dependent noise with the standard deviation proportional to mean). PN is unlikely to be dominant in synthetic systems, and the control objectives of natural movements (speed and accuracy) would not be optimized in synthetic systems by human-like movements. Thus, employing MJ or MV controllers in robotic arms is just aesthetic biomimetics. For prosthetic arms, the goal is aesthetic by definition, but it is still crucial to recognize that MV trajectories and PN are deeply embedded in the human motor system. Thus, PN arises at the neural level, as a recruitment strategy of motor units and probably optimizes motor neuron noise. Human reaching is under continuous adaptive control. For prosthetic devices that do not have this natural architecture, natural plasticity would drive the system towards unnatural movements. We propose that a truly neuromorphic system with parallel force generators (muscle fibres) and noisy

  4. Formation of nano-hydroxyapatite crystal in situ in chitosan-pectin polyelectrolyte complex network

    Energy Technology Data Exchange (ETDEWEB)

    Li Junjie [Department of Polymer Science and Key Laboratory of Systems Bioengineering of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 (China); Research Institute of Polymeric Materials, Tianjin University, Tianjin, 300072 (China); Zhu Dunwan [Institute of Biomedical Engineering, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, 300072 (China); Yin Jianwei; Liu Yuxi [Department of Polymer Science and Key Laboratory of Systems Bioengineering of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 (China); Yao Fanglian, E-mail: yaofanglian@tju.edu.cn [Department of Polymer Science and Key Laboratory of Systems Bioengineering of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 (China); Yao Kangde [Research Institute of Polymeric Materials, Tianjin University, Tianjin, 300072 (China)

    2010-07-20

    Hydroxyapatite (HA)/polysaccharide composites have been widely used in bone tissue engineering due to their chemical similarity to natural bone. Polymer matrix-mediated synthesis of nano-hydroxyapatite is one of the simplest models for biomimetic. In this article, the nano-hydroxyapatite/chitosan-pectin (nHCP) composites were prepared through in situ mineralization of hydroxyapatite in chitosan-pectin polyelectrolyte complex (PEC) network. The formation processes of nHCP were investigated by X-ray diffraction (XRD) analysis. The interactions between nHA crystal and chitosan-pectin PEC networks were studied using Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). The morphology and structure of nHA crystal were characterized by XRD and Transmission Electron Microscope (TEM). Results suggested that the interfacial interactions between nano-hydroxyapatite crystal and chitosan-pectin PEC network assist the site specific nucleation and growth of nHA nanoparticles. The nHA crystals grow along the c-axis. In this process, pH value is the main factor to control the nucleation and growth of nHA crystal in chitosan-pectin PEC networks, because both the interactions' strength between nHA crystal and chitosan-pectin and diffusion rate of inorganic ions depend on the pH value of the reaction system. Apart from the pH value, the chitosan/pectin ratio and [Ca{sup 2+}] also take important effects on the formation of nHA crystal. An effective way to control the size of nHA crystal is to adjust the content of pectin and [Ca{sup 2+}]. It is interesting that the Zeta potential of nHCP composites is about - 30 mV when the chitosan/pectin ratio {<=} 1:1, and the dispersion solution of nHCP composites has higher stability, which provides the possibility to prepare 3D porous scaffolds with nHCP for bone tissue engineering.

  5. Bioactive polyurethane implants with hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Rozhnova, R.; Kebuladze, I.; Galatenko, N. [NAS Ukraine, Kiev (Ukraine). Dept. of Polymers of Medical Appointment

    2001-07-01

    Biologically active polyurethane compositions for plastic of bone defects that contain bioceramic - hydroxyapatite (HAP) and immunomodulator - levamisole (LEV) were designed. The influence of the biologically active fillers in structure polyurethane compositions on their physical and chemical properties in condition in vivo by method of Equilibrium Swelling, method of IR-spectroscopy, roentgen-structural analysis was studied. The introduce in structure of the biodegraded polymeric matrix of HAP is established to promote accumulation of the inorganic component of bone tissue in vivo which is being by basis of the bone formation in regenerating tissue. (orig.)

  6. Grafted SiC nanocrystals

    DEFF Research Database (Denmark)

    Saini, Isha; Sharma, Annu; Dhiman, Rajnish

    2017-01-01

    ), raman spectroscopy and X-ray diffraction (XRD) measurements. UV–Visible absorption spectroscopy was used to study optical properties such as optical energy gap (Eg), Urbach's energy (Eu), refractive index (n), real (ε1) and imaginary (ε2) parts of dielectric constant of PVA as well as PVA......Polyvinyl alcohol (PVA) grafted SiC (PVA-g-SiC)/PVA nanocomposite was synthesized by incorporating PVA grafted silicon carbide (SiC) nanocrystals inside PVA matrix. In-depth structural characterization of resulting nanocomposite was carried out using fourier transform infrared spectroscopy (FTIR...

  7. Biomimetics as a design methodology – possibilities and challenges

    DEFF Research Database (Denmark)

    Lenau, Torben Anker

    2009-01-01

    Biomimetics – or bionik as it is called in parts of Europe – offer a number of promising opportunities and challenges for the designer. The paper investigates how biomimetics as a design methodology is used in engineering design by looking at examples of biological searches and highlight...

  8. Biomimetics: The early years | Michael | Annals of Ibadan ...

    African Journals Online (AJOL)

    Biomimetics is a relatively new term and an evolving discipline with the potentials for transforming every aspect of medicine. Biomimetics or biomimicry is the imitation of the models, systems, and elements of nature for the purpose of solving complex biological puzzles. Insights into biological processes have already resulted ...

  9. Biomimetic mineral coatings in dental and orthopaedic implantology

    NARCIS (Netherlands)

    Liu, Y.; de Groot, K.; Hunziker, E.B.

    2009-01-01

    Biomimetic techniques are used to deposit coatings of calcium phosphate upon medical devices. The procedure is conducted under near-physiological, or "biomimetic", conditions of temperature and pH primarily to improve their biocompatibility and biodegradability of the materials. The inorganic layers

  10. Synthesis, characterization, and application of nano hydroxyapatite and nanocomposite of hydroxyapatite with granular activated carbon for the removal of Pb{sup 2+} from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Fernando, M. Shanika [Department of Chemistry, University of Colombo, Colombo 03 (Sri Lanka); Silva, Rohini M. de, E-mail: rohini@chem.cmb.ac.lk [Department of Chemistry, University of Colombo, Colombo 03 (Sri Lanka); Silva, K.M. Nalin de [Department of Chemistry, University of Colombo, Colombo 03 (Sri Lanka); Sri Lanka Institute of Nanotechnology, Nanotechnology and Science Park, Mahenwatta, Pitipana, Homagama (Sri Lanka)

    2015-10-01

    Highlights: • Synthesis of neat nano Hydroxyapatite using wet chemical precipitation methods. • This resulted rod like nanocrystals with a diameter around 50–80 nm. • Impregnation of of nano HAp onto the granular activated carbon (GAC) was achieved. • Materials were characterized using FT-IR, PXRD, and SEM. • Adsorption studies were conducted for Pb{sup 2+} ions. • The adsorption data were evaluated according to isotherm models. - Abstract: Synthesis of neat nano hydroxyapatite (HAp) was carried out using wet chemical precipitation methods at low temperature and this resulted rod like HAp nanocrystals with a diameter around 50–80 nm and length of about 250 nm. Impregnation of nano HAp onto the granular activated carbon (GAC) to prepare hydroxyapatite granular activated carbon nanocomposite (C-HAp) was carried out using in situ synthesis of nano HAp in the presence of GAC. The samples of neat nano HAp and C-HAp composite were characterized using Fourier-Transformed Infrared Spectroscopy (FT-IR), powder X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Detailed adsorption studies of neat nano HAp, C-HAp and neat GAC were conducted for Pb{sup 2+} ions at room temperature at different pH levels. The adsorption data for Pb{sup 2+} ions was evaluated according to both Langmuir and Freundlich adsorption isotherm models for both neat nano HAp and C-HAp separately at ambient temperature, 298 K. The equilibrium adsorption data were fitted well with Langmuir adsorption isotherm for neat nano HAp with an adsorption capacity in the range of 138–83 mg g{sup −1}. For C-HAp nanocomposite the adsorption data were well fitted with Freundlich model and the calculated adsorption capacity was in the range of 9–14 mg g{sup −1}. Leaching of Ca{sup 2+} ions by neat nano HAp and C-HAp were also analyzed as a function of pH. It was found that the leaching of Ca{sup 2+} was high in neat HAp than C-HAp. The leaching of Ca{sup 2+} by neat HAp and C

  11. Synthesis, characterization, and application of nano hydroxyapatite and nanocomposite of hydroxyapatite with granular activated carbon for the removal of Pb2+ from aqueous solutions

    International Nuclear Information System (INIS)

    Fernando, M. Shanika; Silva, Rohini M. de; Silva, K.M. Nalin de

    2015-01-01

    Highlights: • Synthesis of neat nano Hydroxyapatite using wet chemical precipitation methods. • This resulted rod like nanocrystals with a diameter around 50–80 nm. • Impregnation of of nano HAp onto the granular activated carbon (GAC) was achieved. • Materials were characterized using FT-IR, PXRD, and SEM. • Adsorption studies were conducted for Pb 2+ ions. • The adsorption data were evaluated according to isotherm models. - Abstract: Synthesis of neat nano hydroxyapatite (HAp) was carried out using wet chemical precipitation methods at low temperature and this resulted rod like HAp nanocrystals with a diameter around 50–80 nm and length of about 250 nm. Impregnation of nano HAp onto the granular activated carbon (GAC) to prepare hydroxyapatite granular activated carbon nanocomposite (C-HAp) was carried out using in situ synthesis of nano HAp in the presence of GAC. The samples of neat nano HAp and C-HAp composite were characterized using Fourier-Transformed Infrared Spectroscopy (FT-IR), powder X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Detailed adsorption studies of neat nano HAp, C-HAp and neat GAC were conducted for Pb 2+ ions at room temperature at different pH levels. The adsorption data for Pb 2+ ions was evaluated according to both Langmuir and Freundlich adsorption isotherm models for both neat nano HAp and C-HAp separately at ambient temperature, 298 K. The equilibrium adsorption data were fitted well with Langmuir adsorption isotherm for neat nano HAp with an adsorption capacity in the range of 138–83 mg g −1 . For C-HAp nanocomposite the adsorption data were well fitted with Freundlich model and the calculated adsorption capacity was in the range of 9–14 mg g −1 . Leaching of Ca 2+ ions by neat nano HAp and C-HAp were also analyzed as a function of pH. It was found that the leaching of Ca 2+ was high in neat HAp than C-HAp. The leaching of Ca 2+ by neat HAp and C-HAp during adsorption of Pb 2+ ions were also

  12. Ostrich eggshell as calcium source for the synthesis of hydroxyapatite and hydroxyapatite partially substituted with zinc

    International Nuclear Information System (INIS)

    Ferreira, J.R.M.; Louro, L.H.L.; Costa, A.M.; Silva, M.H. Prado da; Campos, J.B. de

    2016-01-01

    In the present study, hydroxyapatite and Zn-substituted hydroxyapatite powders were synthesized using ostrich eggshell as a calcium source. The samples were analyzed by scanning electron microscopy with field emission gun, and X-ray diffraction (XRD) to identify the present phases, and X-ray fluorescence spectroscopy for quantitative chemical analysis of the synthesized and heat treated powders. The Fourier transform infrared spectroscopy technique was used before and after heat treatments at 700, 900 and 1100 °C in order to identify the functional groups present, as an additional technique to the XRD analysis. The results presented in this study represent a promising method for synthesis of hydroxyapatite and hydroxyapatite partially substituted with zinc, since the results showed no undesirable phases or impurities in the produced powders. It was observed that Zn-substituted hydroxyapatite showed higher thermal stability, when compared to pure hydroxyapatite. (author)

  13. Ostrich eggshell as calcium source for the synthesis of hydroxyapatite and hydroxyapatite partially substituted with zinc

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, J.R.M.; Louro, L.H.L.; Costa, A.M.; Silva, M.H. Prado da [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil); Campos, J.B. de, E-mail: josericardo@r-crio.com, E-mail: louro@ime.eb.br, E-mail: andrea@r-crio.com, E-mail: brantjose@gmail.com, E-mail: marceloprado@ime.eb.br [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil)

    2016-10-15

    In the present study, hydroxyapatite and Zn-substituted hydroxyapatite powders were synthesized using ostrich eggshell as a calcium source. The samples were analyzed by scanning electron microscopy with field emission gun, and X-ray diffraction (XRD) to identify the present phases, and X-ray fluorescence spectroscopy for quantitative chemical analysis of the synthesized and heat treated powders. The Fourier transform infrared spectroscopy technique was used before and after heat treatments at 700, 900 and 1100 °C in order to identify the functional groups present, as an additional technique to the XRD analysis. The results presented in this study represent a promising method for synthesis of hydroxyapatite and hydroxyapatite partially substituted with zinc, since the results showed no undesirable phases or impurities in the produced powders. It was observed that Zn-substituted hydroxyapatite showed higher thermal stability, when compared to pure hydroxyapatite. (author)

  14. Ostrich eggshell as calcium source for the synthesis of hydroxyapatite and hydroxyapatite partially substituted with zinc

    Directory of Open Access Journals (Sweden)

    J. R. M. Ferreira

    Full Text Available Abstract In the present study, hydroxyapatite and Zn-substituted hydroxyapatite powders were synthesized using ostrich eggshell as a calcium source. The samples were analyzed by scanning electron microscopy with field emission gun, and X-ray diffraction (XRD to identify the present phases, and X-ray fluorescence spectroscopy for quantitative chemical analysis of the synthesized and heat treated powders. The Fourier transform infrared spectroscopy technique was used before and after heat treatments at 700, 900 and 1100 °C in order to identify the functional groups present, as an additional technique to the XRD analysis. The results presented in this study represent a promising method for synthesis of hydroxyapatite and hydroxyapatite partially substituted with zinc, since the results showed no undesirable phases or impurities in the produced powders. It was observed that Zn-substituted hydroxyapatite showed higher thermal stability, when compared to pure hydroxyapatite.

  15. Hydroxyapatite/MCM-41 and SBA-15 Nano-Composites: Preparation, Characterization and Applications

    Science.gov (United States)

    Anunziata, Oscar A.; Martínez, Maria L.; Beltramone, Andrea R.

    2009-01-01

    Composites of hydroxyapatite (HaP) and highly ordered large pore mesoporous silica molecular sieves such as, Al-SBA-15 and Al-MCM-41 (denoted as SBA-15 and MCM-41, respectively) were developed, characterized by XRD, BET, FTIR, HRTEM and NMR-MAS, and applied to fluoride retention from contaminated water. The proposed procedure by a new route to prepare the HaP/SBA-15 and HaP/MCM-41, composites generates materials with aluminum only in tetrahedral coordination, according to the 27Al NMR-MAS results. Free OH- groups of HaP nanocrystals, within the hosts, allowed high capacity fluoride retention. The activity of fluoride retention using HaP/MCM-41 or HaP/SBA-15 was 1-2 orders of magnitude greater, respectively, than with pure HaP.

  16. Development Considerations for Nanocrystal Drug Products.

    Science.gov (United States)

    Chen, Mei-Ling; John, Mathew; Lee, Sau L; Tyner, Katherine M

    2017-05-01

    Nanocrystal technology has emerged as a valuable tool for facilitating the delivery of poorly water-soluble active pharmaceutical ingredients (APIs) and enhancing API bioavailability. To date, the US Food and Drug Administration (FDA) has received over 80 applications for drug products containing nanocrystals. These products can be delivered by different routes of administration and are used in a variety of therapeutic areas. To aid in identifying key developmental considerations for these products, a retrospective analysis was performed on the submissions received by the FDA to date. Over 60% of the submissions were for the oral route of administration. Based on the Biopharmaceutics Classification System (BCS), most nanocrystal drugs submitted to the FDA are class II compounds that possess low aqueous solubility and high intestinal permeability. Impact of food on drug bioavailability was reduced for most nanocrystal formulations as compared with their micronized counterparts. For all routes of administration, dose proportionality was observed for some, but not all, nanocrystal products. Particular emphasis in the development of nanocrystal products was placed on the in-process tests and controls at critical manufacturing steps (such as milling process), mitigation and control of process-related impurities, and the stability of APIs or polymorphic form (s) during manufacturing and upon storage. This emphasis resulted in identifying challenges to the development of these products including accurate determination of particle size (distribution) of drug substance and/or nanocrystal colloidal dispersion, identification of polymorphic form (s), and establishment of drug substance/product specifications.

  17. Biomimetics: forecasting the future of science, engineering, and medicine

    Science.gov (United States)

    Hwang, Jangsun; Jeong, Yoon; Park, Jeong Min; Lee, Kwan Hong; Hong, Jong Wook; Choi, Jonghoon

    2015-01-01

    Biomimetics is the study of nature and natural phenomena to understand the principles of underlying mechanisms, to obtain ideas from nature, and to apply concepts that may benefit science, engineering, and medicine. Examples of biomimetic studies include fluid-drag reduction swimsuits inspired by the structure of shark’s skin, velcro fasteners modeled on burrs, shape of airplanes developed from the look of birds, and stable building structures copied from the backbone of turban shells. In this article, we focus on the current research topics in biomimetics and discuss the potential of biomimetics in science, engineering, and medicine. Our report proposes to become a blueprint for accomplishments that can stem from biomimetics in the next 5 years as well as providing insight into their unseen limitations. PMID:26388692

  18. Biomimetics: forecasting the future of science, engineering, and medicine.

    Science.gov (United States)

    Hwang, Jangsun; Jeong, Yoon; Park, Jeong Min; Lee, Kwan Hong; Hong, Jong Wook; Choi, Jonghoon

    2015-01-01

    Biomimetics is the study of nature and natural phenomena to understand the principles of underlying mechanisms, to obtain ideas from nature, and to apply concepts that may benefit science, engineering, and medicine. Examples of biomimetic studies include fluid-drag reduction swimsuits inspired by the structure of shark's skin, velcro fasteners modeled on burrs, shape of airplanes developed from the look of birds, and stable building structures copied from the backbone of turban shells. In this article, we focus on the current research topics in biomimetics and discuss the potential of biomimetics in science, engineering, and medicine. Our report proposes to become a blueprint for accomplishments that can stem from biomimetics in the next 5 years as well as providing insight into their unseen limitations.

  19. Biomimetic Materials and Fabrication Approaches for Bone Tissue Engineering.

    Science.gov (United States)

    Kim, Hwan D; Amirthalingam, Sivashanmugam; Kim, Seunghyun L; Lee, Seunghun S; Rangasamy, Jayakumar; Hwang, Nathaniel S

    2017-12-01

    Various strategies have been explored to overcome critically sized bone defects via bone tissue engineering approaches that incorporate biomimetic scaffolds. Biomimetic scaffolds may provide a novel platform for phenotypically stable tissue formation and stem cell differentiation. In recent years, osteoinductive and inorganic biomimetic scaffold materials have been optimized to offer an osteo-friendly microenvironment for the osteogenic commitment of stem cells. Furthermore, scaffold structures with a microarchitecture design similar to native bone tissue are necessary for successful bone tissue regeneration. For this reason, various methods for fabricating 3D porous structures have been developed. Innovative techniques, such as 3D printing methods, are currently being utilized for optimal host stem cell infiltration, vascularization, nutrient transfer, and stem cell differentiation. In this progress report, biomimetic materials and fabrication approaches that are currently being utilized for biomimetic scaffold design are reviewed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Substituted Hydroxyapatites with Antibacterial Properties

    Directory of Open Access Journals (Sweden)

    Joanna Kolmas

    2014-01-01

    Full Text Available Reconstructive surgery is presently struggling with the problem of infections located within implantation biomaterials. Of course, the best antibacterial protection is antibiotic therapy. However, oral antibiotic therapy is sometimes ineffective, while administering an antibiotic at the location of infection is often associated with an unfavourable ratio of dosage efficiency and toxic effect. Thus, the present study aims to find a new factor which may improve antibacterial activity while also presenting low toxicity to the human cells. Such factors are usually implemented along with the implant itself and may be an integral part of it. Many recent studies have focused on inorganic factors, such as metal nanoparticles, salts, and metal oxides. The advantages of inorganic factors include the ease with which they can be combined with ceramic and polymeric biomaterials. The following review focuses on hydroxyapatites substituted with ions with antibacterial properties. It considers materials that have already been applied in regenerative medicine (e.g., hydroxyapatites with silver ions and those that are only at the preliminary stage of research and which could potentially be used in implantology or dentistry. We present methods for the synthesis of modified apatites and the antibacterial mechanisms of various ions as well as their antibacterial efficiency.

  1. Substituted Hydroxyapatites with Antibacterial Properties

    Science.gov (United States)

    Kolmas, Joanna; Groszyk, Ewa; Kwiatkowska-Różycka, Dagmara

    2014-01-01

    Reconstructive surgery is presently struggling with the problem of infections located within implantation biomaterials. Of course, the best antibacterial protection is antibiotic therapy. However, oral antibiotic therapy is sometimes ineffective, while administering an antibiotic at the location of infection is often associated with an unfavourable ratio of dosage efficiency and toxic effect. Thus, the present study aims to find a new factor which may improve antibacterial activity while also presenting low toxicity to the human cells. Such factors are usually implemented along with the implant itself and may be an integral part of it. Many recent studies have focused on inorganic factors, such as metal nanoparticles, salts, and metal oxides. The advantages of inorganic factors include the ease with which they can be combined with ceramic and polymeric biomaterials. The following review focuses on hydroxyapatites substituted with ions with antibacterial properties. It considers materials that have already been applied in regenerative medicine (e.g., hydroxyapatites with silver ions) and those that are only at the preliminary stage of research and which could potentially be used in implantology or dentistry. We present methods for the synthesis of modified apatites and the antibacterial mechanisms of various ions as well as their antibacterial efficiency. PMID:24949423

  2. Enhanced osteoconductivity of sodium-substituted hydroxyapatite by system instability.

    Science.gov (United States)

    Sang Cho, Jung; Um, Seung-Hoon; Su Yoo, Dong; Chung, Yong-Chae; Hye Chung, Shin; Lee, Jeong-Cheol; Rhee, Sang-Hoon

    2014-07-01

    The effect of substituting sodium for calcium on enhanced osteoconductivity of hydroxyapatite was newly investigated. Sodium-substituted hydroxyapatite was synthesized by reacting calcium hydroxide and phosphoric acid with sodium nitrate followed by sintering. As a control, pure hydroxyapatite was prepared under identical conditions, but without the addition of sodium nitrate. Substitution of calcium with sodium in hydroxyapatite produced the structural vacancies for carbonate ion from phosphate site and hydrogen ion from hydroxide site of hydroxyapatite after sintering. The total system energy of sodium-substituted hydroxyapatite with structural defects calculated by ab initio methods based on quantum mechanics was much higher than that of hydroxyapatite, suggesting that the sodium-substituted hydroxyapatite was energetically less stable compared with hydroxyapatite. Indeed, sodium-substituted hydroxyapatite exhibited higher dissolution behavior of constituent elements of hydroxyapatite in simulated body fluid (SBF) and Tris-buffered deionized water compared with hydroxyapatite, which directly affected low-crystalline hydroxyl-carbonate apatite forming capacity by increasing the degree of apatite supersaturation in SBF. Actually, sodium-substituted hydroxyapatite exhibited markedly improved low-crystalline hydroxyl-carbonate apatite forming capacity in SBF and noticeably higher osteoconductivity 4 weeks after implantation in calvarial defects of New Zealand white rabbits compared with hydroxyapatite. In addition, there were no statistically significant differences between hydroxyapatite and sodium-substituted hydroxyapatite on cytotoxicity as determined by BCA assay. Taken together, these results indicate that sodium-substituted hydroxyapatite with structural defects has promising potential for use as a bone grafting material due to its enhanced osteoconductivity compared with hydroxyapatite. © 2013 Wiley Periodicals, Inc.

  3. Magnetic responsive hydroxyapatite composite scaffolds construction for bone defect reparation

    Directory of Open Access Journals (Sweden)

    Zeng XB

    2012-07-01

    Full Text Available Xiao Bo Zeng, Hao Hu, Li Qin Xie, Fang Lan, Wen Jiang, Yao Wu, Zhong Wei GuNational Engineering Research Center for Biomaterials, Sichuan University, Chengdu, Sichuan, People's Republic of ChinaIntroduction: In recent years, interest in magnetic biomimetic scaffolds for tissue engineering has increased considerably. A type of magnetic scaffold composed of magnetic nanoparticles (MNPs and hydroxyapatite (HA for bone repair has been developed by our research group.Aim and methods: In this study, to investigate the influence of the MNP content (in the scaffolds on the cell behaviors and the interactions between the magnetic scaffold and the exterior magnetic field, a series of MNP-HA magnetic scaffolds with different MNP contents (from 0.2% to 2% were fabricated by immersing HA scaffold into MNP colloid. ROS 17/2.8 and MC3T3-E1 cells were cultured on the scaffolds in vitro, with and without an exterior magnetic field, respectively. The cell adhesion, proliferation and differentiation were evaluated via scanning electron microscopy; confocal laser scanning microscopy; and 3-(4,5-Dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT, alkaline phosphatase, and bone gla protein activity tests.Results: The results demonstrated the positive influence of the magnetic scaffolds on cell adhesion, proliferation, and differentiation. Further, a higher amount of MNPs on the magnetic scaffolds led to more significant stimulation.Conclusion: The magnetic scaffold can respond to the exterior magnetic field and engender some synergistic effect to intensify the stimulating effect of a magnetic field to the proliferation and differentiation of cells.Keywords: magnetic therapy, magnetic nanoparticles, bone repair, magnetic responsive

  4. Charge transport in a CoPt3 nanocrystal microwire

    International Nuclear Information System (INIS)

    Beecher, P.; De Marzi, G.; Quinn, A.J.; Redmond, G.; Shevchenko, E.V.; Weller, H.

    2004-01-01

    The electrical characteristics of single CoPt 3 nanocrystal microwires formed by magnetic field-directed growth from colloidal solutions are presented. The wires comprise disordered assemblies of discrete nanocrystals, separated from each other by protective organic ligand shells. Electrical data indicate that the activated charge transport properties of the wires are determined by the nanocrystal charging energy, governed by the size and capacitance of the individual nanocrystals. Focused ion beam-assisted deposition of Pt metal at the wire-electrode junctions is employed to optimize the wire-electrode contacts, whilst maintaining the nanocrystal-dominated transport characteristics of these one-dimensional nanocrystal structures

  5. Composite material including nanocrystals and methods of making

    Science.gov (United States)

    Bawendi, Moungi G.; Sundar, Vikram C.

    2010-04-06

    Temperature-sensing compositions can include an inorganic material, such as a semiconductor nanocrystal. The nanocrystal can be a dependable and accurate indicator of temperature. The intensity of emission of the nanocrystal varies with temperature and can be highly sensitive to surface temperature. The nanocrystals can be processed with a binder to form a matrix, which can be varied by altering the chemical nature of the surface of the nanocrystal. A nanocrystal with a compatibilizing outer layer can be incorporated into a coating formulation and retain its temperature sensitive emissive properties.

  6. High Temperature AL-Nanocrystal Alloy Synthesis

    National Research Council Canada - National Science Library

    Perepezko, J

    2001-01-01

    Aluminum-rich metallic glasses containing transition metals and rare earth elements have been found to yield finely mixed microstructures of Al nanocrystals embedded in an amorphous matrix and exhibit...

  7. Semiconductor-nanocrystal/conjugated polymer thin films

    Science.gov (United States)

    Alivisatos, A. Paul; Dittmer, Janke J.; Huynh, Wendy U.; Milliron, Delia

    2014-06-17

    The invention described herein provides for thin films and methods of making comprising inorganic semiconductor-nanocrystals dispersed in semiconducting-polymers in high loading amounts. The invention also describes photovoltaic devices incorporating the thin films.

  8. Synthesis of nanocrystalline fluorinated hydroxyapatite by ...

    Indian Academy of Sciences (India)

    The biological hydroxyapatite in the human bone and tooth is of nanosize and ... The crystal size and morphology of the nanopowders were examined by X-ray powder diffraction .... tal growth along the c axis of HA crystalline structure. The.

  9. Substituted hydroxyapatites for biomedical applications: A review

    Czech Academy of Sciences Publication Activity Database

    Šupová, Monika

    2015-01-01

    Roč. 41, č. 8 (2015), s. 9203-9231 ISSN 0272-8842 Institutional support: RVO:67985891 Keywords : bioapatite * calcium phosphate * hydroxyapatite * substitution Subject RIV: JJ - Other Materials Impact factor: 2.758, year: 2015

  10. Spectral analysis of allogeneic hydroxyapatite powders

    Science.gov (United States)

    Timchenko, P. E.; Timchenko, E. V.; Pisareva, E. V.; Vlasov, M. Yu; Red'kin, N. A.; Frolov, O. O.

    2017-01-01

    In this paper we discuss the application of Raman spectroscopy to the in vitro analysis of the hydroxyapatite powder samples produced from different types of animal bone tissue during demineralization process at various acid concentrations and exposure durations. The derivation of the Raman spectrum of hydroxyapatite is attempted by the analysis of the pure powders of its known constituents. Were experimentally found spectral features of hydroxyapatite, based on analysis of the line amplitude at wave numbers 950-965 cm-1 ((PO4)3- (ν1) vibration) and 1065-1075 cm-1 ((CO3)2-(ν1) B-type replacement). Control of physicochemical properties of hydroxyapatite was carried out by Raman spectroscopy. Research results are compared with an infrared Fourier spectroscopy.

  11. Spectral analysis of allogeneic hydroxyapatite powders

    International Nuclear Information System (INIS)

    Timchenko, P E; Timchenko, E V; Pisareva, E V; Vlasov, M Yu; Red’kin, N A; Frolov, O O

    2017-01-01

    In this paper we discuss the application of Raman spectroscopy to the in vitro analysis of the hydroxyapatite powder samples produced from different types of animal bone tissue during demineralization process at various acid concentrations and exposure durations. The derivation of the Raman spectrum of hydroxyapatite is attempted by the analysis of the pure powders of its known constituents. Were experimentally found spectral features of hydroxyapatite, based on analysis of the line amplitude at wave numbers 950-965 cm -1 ((PO 4 ) 3- (ν 1 ) vibration) and 1065-1075 cm -1 ((CO 3 ) 2- (ν 1 ) B-type replacement). Control of physicochemical properties of hydroxyapatite was carried out by Raman spectroscopy. Research results are compared with an infrared Fourier spectroscopy. (paper)

  12. Biomimetic magnetic nanocomposite for smart skins

    KAUST Repository

    Alfadhel, Ahmed; Kosel, Jü rgen

    2015-01-01

    We report a biomimetic tactile sensor consisting of magnetic nanocomposite artificial cilia and magnetic sensors. The nanocomposite is fashioned from polydimethylsiloxane and iron nanowires and exhibits a permanent magnetic behavior. This enables remote operation without an additional magnetic field to magnetize the nanowires, which simplifies device integration. Moreover, the highly elastic and easy patternable nanocomposite is corrosion resistant and thermally stable. The highly sensitive and power efficient tactile sensors can detect vertical and shear forces from interactions with objects. The sensors can operate in dry and wet environment with the ability to measure different properties such as the texture and the movement or stability of objects, with easily adjustable performance.

  13. Proteins and Peptides in Biomimetic Polymeric Membranes

    DEFF Research Database (Denmark)

    Perez, Alfredo Gonzalez

    2013-01-01

    This chapter discusses recent advances and the main advantages of block copolymers for functional membrane protein reconstitution in biomimetic polymeric membranes. A rational approach to the reconstitution of membrane proteins in a functional form can be addressed by a more holistic view by using...... other kind of nonbiological amphiphilic molecules. An interesting possibility could be the use of self-assembled proteins in a lipid-free membrane mimicking the capside of some viruses. The membrane proteins that have been more actively used in combination with block copolymer membranes are gramicidin...

  14. Biotechnologies and biomimetics for civil engineering

    CERN Document Server

    Labrincha, J; Diamanti, M; Yu, C-P; Lee, H

    2015-01-01

    Putting forward an innovative approach to solving current technological problems faced by human society, this book encompasses a holistic way of perceiving the potential of natural systems. Nature has developed several materials and processes which both maintain an optimal performance and are also totally biodegradable, properties which can be used in civil engineering. Delivering the latest research findings to building industry professionals and other practitioners, as well as containing information useful to the public, ‘Biotechnologies and Biomimetics for Civil Engineering’ serves as an important tool to tackle the challenges of a more sustainable construction industry and the future of buildings.

  15. Biomimetic magnetic nanocomposite for smart skins

    KAUST Repository

    Alfadhel, Ahmed

    2015-11-01

    We report a biomimetic tactile sensor consisting of magnetic nanocomposite artificial cilia and magnetic sensors. The nanocomposite is fashioned from polydimethylsiloxane and iron nanowires and exhibits a permanent magnetic behavior. This enables remote operation without an additional magnetic field to magnetize the nanowires, which simplifies device integration. Moreover, the highly elastic and easy patternable nanocomposite is corrosion resistant and thermally stable. The highly sensitive and power efficient tactile sensors can detect vertical and shear forces from interactions with objects. The sensors can operate in dry and wet environment with the ability to measure different properties such as the texture and the movement or stability of objects, with easily adjustable performance.

  16. Heterogeneous and self-organizing mineralization of bone matrix promoted by hydroxyapatite nanoparticles.

    Science.gov (United States)

    Campi, G; Cristofaro, F; Pani, G; Fratini, M; Pascucci, B; Corsetto, P A; Weinhausen, B; Cedola, A; Rizzo, A M; Visai, L; Rea, G

    2017-11-16

    The mineralization process is crucial to the load-bearing characteristics of the bone extracellular matrix. In this work, we have studied the spatiotemporal dynamics of mineral deposition by human bone marrow mesenchymal stem cells differentiating toward osteoblasts promoted by the presence of exogenous hydroxyapatite nanoparticles. At the molecular level, the added nanoparticles positively modulated the expression of bone-specific markers and enhanced calcified matrix deposition during osteogenic differentiation. The nucleation, growth and spatial arrangement of newly deposited hydroxyapatite nanocrystals have been evaluated using scanning micro X-ray diffraction and scanning micro X-ray fluorescence. As leading results, we have found the emergence of a complex scenario where the spatial organization and temporal evolution of the process exhibit heterogeneous and self-organizing dynamics. At the same time the possibility of controlling the differentiation kinetics, through the addition of synthetic nanoparticles, paves the way to empower the generation of more structured bone scaffolds in tissue engineering and to design new drugs in regenerative medicine.

  17. Photoluminescence of nanocrystals embedded in oxide matrices

    International Nuclear Information System (INIS)

    Estrada, C.; Gonzalez, J.A.; Kunold, A.; Reyes-Esqueda, J.A.; Pereyra, P.

    2006-12-01

    We used the theory of finite periodic systems to explain the photoluminescence spectra dependence on the average diameter of nanocrystals embedded in oxide matrices. Because of the broad matrix band gap, the photoluminescence response is basically determined by isolated nanocrystals and sequences of a few of them. With this model we were able to reproduce the shape and displacement of the experimentally observed photoluminescence spectra. (author)

  18. Separation of lanthanides through hydroxyapatite

    International Nuclear Information System (INIS)

    Garcia M, F.G.

    2006-01-01

    With the objective of obtaining from an independent way to each one of the lanthanides 151 Pm, 161 Tb, 166 Ho and 177 Lu free of carrier and with high specific activities starting from the indirect irradiation via, it intends in this work to determine the viability of separation of the couples Nd/Pm, Dy/Ho, Gd/Tb and Yb/Lu, by means of ion exchange column chromatography, using hydroxyapatite (HAp) and fluorite like absorbent material in complexing media. It is important to mention that have registered separation studies among lanthanides of the heavy group with those of the slight group, using the same mass and, in comparison with this work, quantities different from the father were used and of the son, also, that the separation studies were carried out among neighboring lanthanides. In this investigation, it was determined the effect that its have the complexing media: KSCN, sodium tartrate, sodium citrate, EDTA and aluminon, their pH and concentration, in the adsorption of the lanthanides in both minerals, in order to determine the chromatographic conditions for separation of the couples Nd/Pm, Dy/Ho, Gd/Tb and Yb/Lu. The work consists of five chapters, in the first one they are presented a theoretical introduction of the characteristics more important of the lanthanides, the hydroxyapatite and the fluorite; in the second, it is deepened in the ion exchange, as well as the two techniques (XRD and High Vacuum Electron Microscopy) to make the characterization of LnCI 3 (Ln = Nd, Gd, Dy or Yb) synthesized. The third chapter, it describes the methodology continued in our experimental work; in the room, its are presented the obtained results of the static and dynamic method to determine the viability of separation of neighboring lanthanides; and finally, the five chapter shows the conclusions. In this study, it is concludes that the separation among neighboring lanthanides cannot be carried out in the minerals and used media; because practically these lanthanides

  19. Ion exchange of strontium on synthetic hydroxyapatite

    International Nuclear Information System (INIS)

    Lazic, S.; Vukovic, Z.

    1991-01-01

    Adsorption of strontium ions on synthetic hydroxyapatite was examined using both batch and column methods. The apatite was prepared from aqueous solutions and characterized by standard analytical methods. The sample obtained had characteristics of well crystallized stoichiometric hydroxyapatite. The experimental data for sorption of strontium can be very well fitted with Langmuir's adsorption isotherm. It was found that sorption occurs by an ion exchange reaction between strontium ions in solution and calcium ions in apatite. (author) 14 refs.; 5 figs.; 1 tab

  20. Applying analytical ultracentrifugation to nanocrystal suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Jamison, Jennifer A; Krueger, Karl M; Mayo, J T; Yavuz, Cafer T; Redden, Jacina J; Colvin, Vicki L, E-mail: colvin@rice.ed [Department of Chemistry, Rice University, 6100 Main Street, MS-60, Houston, TX 77005 (United States)

    2009-09-02

    While applied frequently in physical biochemistry to the study of protein complexes, the quantitative use of analytical ultracentrifugation (AUC) for nanocrystal analysis is relatively rare. Its application in nanoscience is potentially very powerful as it provides a measure of nanocrystal density, size and structure directly in the solution phase. Towards that end, this paper examines the best practices for applying data collection and analysis methods for AUC, geared towards the study of biomolecules, to the unique problems of nanoparticle analysis. Using uniform nanocrystals of cadmium selenide, we compared several schemes for analyzing raw sedimentation data. Comparable values of the mean sedimentation coefficients (s-value) were found using several popular analytical approaches; however, the distribution in sample s-values is best captured using the van Holde-Weischt algorithm. Measured s-values could be reproducibly collected if sample temperature and concentration were controlled; under these circumstances, the variability for average sedimentation values was typically 5%. The full shape of the distribution in s-values, however, is not easily subjected to quantitative interpretation. Moreover, the selection of the appropriate sedimentation speed is crucial for AUC of nanocrystals as the density of inorganic nanocrystals is much larger than that of solvents. Quantitative analysis of sedimentation properties will allow for better agreement between experimental and theoretical models of nanocrystal solution behavior, as well as providing deeper insight into the hydrodynamic size and solution properties of nanomaterials.

  1. Facial skeletal augmentation using hydroxyapatite cement.

    Science.gov (United States)

    Shindo, M L; Costantino, P D; Friedman, C D; Chow, L C

    1993-02-01

    This study investigates the use of a new calcium phosphate cement, which sets to solid, microporous hydroxyapatite, for facial bone augmentation. In six dogs, the supraorbital ridges were augmented bilaterally with this hydroxyapatite cement. On one side, the hydroxyapatite cement was placed directly onto the bone within a subperiosteal pocket. On the opposite side, the cement was contained within a collagen membrane tubule and then inserted into a subperiosteal pocket. The use of collagen tubules facilitated easy, precise placement of the cement. All implants maintained their original augmented height throughout the duration of the study. They were well tolerated without extrusion or migration, and there was no significant sustained inflammatory response. Histologic studies, performed at 3, 6, and 9 months revealed that when the cement was placed directly onto bone, progressive replacement of the implant by bone (osseointegration of the hydroxyapatite with the underlying bone) without a loss of volume was observed. In contrast, when the cement-collagen tubule combination was inserted, primarily a fibrous union was noted. Despite such fibrous union, the hydroxyapatite-collagen implant solidly bonded to the underlying bone, and no implant resorption was observed. Hydroxyapatite cement can be used successfully for the experimental augmentation of the craniofacial skeleton and may be applicable for such uses in humans.

  2. Biomimetic High-Density Lipoproteins from a Gold Nanoparticle Template

    Science.gov (United States)

    Luthi, Andrea Jane

    For hundreds of years the field of chemistry has looked to nature for inspiration and insight to develop novel solutions for the treatment of human diseases. The ability of chemists to identify, mimic, and modifiy small molecules found in nature has led to the discovery and development of many important therapeutics. Chemistry on the nanoscale has made it possible to mimic natural, macromolecular structures that may also be useful for understanding and treating diseases. One example of such a structure is high-density lipoprotein (HDL). The goal of this work is to use a gold nanoparticle (Au NP) as a template to synthesize functional mimics of HDL and characterize their structure and function. Chapter 1 details the structure and function of natural HDL and how chemistry on the nanoscale provides new strategies for mimicking HDL. This Chapter also describes the first examples of using nanoparticles to mimic HDL. Chapter 2 reports the synthesis and characterization of biomimetic HDL using different sizes of Au NPs and different surface chemistries and how these variables can be used to tailor the properties of biomimetic HDL. From these studies the optimal strategy for synthesizing biomimetic HDL was determined. In Chapter 3, the optimization of the synthesis of biomimetic HDL is discussed as well as a full characterization of its structure. In addition, the work in this chapter shows that biomimetic HDL can be synthesized on a large scale without alterations to its structure or function. Chapter 4 focuses on understanding the pathways by which biomimetic HDL accepts cholesterol from macrophage cells. The results of these studies demonstrate that biomimetic HDL is able to accept cholesterol by both active and passive pathways of cholesterol efflux. In Chapter 5 the preliminary results of in vivo studies to characterize the pharmacokinetics and pharmacodynamics of biomimetic HDL are presented. These studies suggest that biomimetic HDL traffics through tissues prone to

  3. Using Biomimetic Polymers in Place of Noncollagenous Proteins to Achieve Functional Remineralization of Dentin Tissues

    Energy Technology Data Exchange (ETDEWEB)

    Chien, Yung-Ching [Molecular; Department; Tao, Jinhui [Molecular; Physical; Saeki, Kuniko [Department; Chin, Alexander F. [Department; Lau, Jolene L. [Molecular; Chen, Chun-Long [Molecular; Physical; Zuckermann, Ronald N. [Molecular; Marshall, Sally J. [Department; Marshall, Grayson W. [Department; De Yoreo, James J. [Molecular; Physical; Department

    2017-11-16

    In calcified tissues such as bones and teeth, mineralization is regulated by an extracellular matrix, which includes non-collagenous proteins (NCP). This natural process has been adapted or mimicked to restore tissues following physical damage or demineralization by using polyanionic acids in place of NCPs, but the remineralized tissues fail to fully recover their mechanical properties. Here we show that pre-treatment with certain amphiphilic peptoids, a class of peptide-like polymers consisting of N-substituted glycines that have defined monomer sequences, enhances ordering and mineralization of collagen and induces functional remineralization of dentin lesions in vitro. In the vicinity of dentin tubules, the newly formed apatite nano-crystals are co-aligned with the c-axis parallel to the tubular periphery and recovery of tissue ultrastructure is accompanied by development of high mechanical strength. The observed effects are highly sequence-dependent with alternating polar and non-polar groups leading to positive outcomes while diblock sequences have no effect. The observations suggest aromatic groups interact with the collagen while the hydrophilic side chains bind the mineralizing constituents and highlight the potential of synthetic sequence-defined biomimetic polymers to serve as NCP mimics in tissue remineralization.

  4. Bright trions in direct-bandgap silicon nanocrystals revealed bylow-temperature single-nanocrystal spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Kůsová, Kateřina; Pelant, Ivan; Valenta, J.

    2015-01-01

    Roč. 4, Oct (2015), e336 ISSN 2047-7538 R&D Projects: GA ČR(CZ) GBP108/12/G108; GA ČR GPP204/12/P235 Institutional support: RVO:68378271 Keywords : silicon nanocrystals * single-nanocrystal spectroscopy * luminescing trions Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 13.600, year: 2015

  5. Solution synthesis of germanium nanocrystals

    Science.gov (United States)

    Gerung, Henry [Albuquerque, NM; Boyle, Timothy J [Kensington, MD; Bunge, Scott D [Cuyahoga Falls, OH

    2009-09-22

    A method for providing a route for the synthesis of a Ge(0) nanometer-sized material from. A Ge(II) precursor is dissolved in a ligand heated to a temperature, generally between approximately 100.degree. C. and 400.degree. C., sufficient to thermally reduce the Ge(II) to Ge(0), where the ligand is a compound that can bond to the surface of the germanium nanomaterials to subsequently prevent agglomeration of the nanomaterials. The ligand encapsulates the surface of the Ge(0) material to prevent agglomeration. The resulting solution is cooled for handling, with the cooling characteristics useful in controlling the size and size distribution of the Ge(0) materials. The characteristics of the Ge(II) precursor determine whether the Ge(0) materials that result will be nanocrystals or nanowires.

  6. Polyimide Cellulose Nanocrystal Composite Aerogels

    Science.gov (United States)

    Nguyen, Baochau N.; Meador, Mary Ann; Rowan, Stuart; Cudjoe, Elvis; Sandberg, Anna

    2014-01-01

    Polyimide (PI) aerogels are highly porous solids having low density, high porosity and low thermal conductivity with good mechanical properties. They are ideal for various applications including use in antenna and insulation such as inflatable decelerators used in entry, decent and landing operations. Recently, attention has been focused on stimuli responsive materials such as cellulose nano crystals (CNCs). CNCs are environmentally friendly, bio-renewable, commonly found in plants and the dermis of sea tunicates, and potentially low cost. This study is to examine the effects of CNC on the polyimide aerogels. The CNC used in this project are extracted from mantle of a sea creature called tunicates. A series of polyimide cellulose nanocrystal composite aerogels has been fabricated having 0-13 wt of CNC. Results will be discussed.

  7. Biomimetic nanoparticles with polynucleotide and PEG mixed-monolayers enhance calcium phosphate mineralization

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcellos, Kayla B.; McHugh, Sean M.; Dapsis, Katherine J.; Petty, Alexander R.; Gerdon, Aren E., E-mail: gerdoar@emmanuel.edu [Emmanuel College (United States)

    2013-09-15

    Biomineralization of hydroxyapatite (Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}) is of significant importance in biomedical applications such as bone and dental repair, and biomimetic control of mineral formation may lead to more effective restorative procedures. Gold nanoparticles are functional scaffolds on which to assemble multi-component monolayers capable of mimicking protein activity in the templated synthesis of calcium phosphate. The goal of this research was to explore nanoparticle templates with mixed-monolayers of uncharged polar polyethylene glycol (PEG) molecules and highly charged polynucleotide and amino acid molecules in their ability to influence mineralization rates and mineral particle size and morphology. This research demonstrates through time-resolved optical density and dynamic light scattering measurements that the combination of tiopronin, PEG, and DNA presented on a nanoparticle surface decreases nanoparticle aggregation from 59 to 21 nm solvated radius, increases mineralization kinetics from 1.5 Multiplication-Sign 10{sup -3} to 3.1 Multiplication-Sign 10{sup -3} OD/min, and decreases mineral particle size from 685 to 442 nm average radius. FT-IR and TEM data demonstrate that mineralized material, while initially amorphous, transforms to a semi-crystalline material when guided by template interactions. This demonstrates that surface-tailored monolayer protected cluster scaffolds are successful and controllable mineralization templates with further potential for biomedical applications involving calcium phosphate and other biomaterials.

  8. Water-Soluble Cellulose Derivatives Are Sustainable Additives for Biomimetic Calcium Phosphate Mineralization

    Directory of Open Access Journals (Sweden)

    Andreas Taubert

    2016-10-01

    Full Text Available The effect of cellulose-based polyelectrolytes on biomimetic calcium phosphate mineralization is described. Three cellulose derivatives, a polyanion, a polycation, and a polyzwitterion were used as additives. Scanning electron microscopy, X-ray diffraction, IR and Raman spectroscopy show that, depending on the composition of the starting solution, hydroxyapatite or brushite precipitates form. Infrared and Raman spectroscopy also show that significant amounts of nitrate ions are incorporated in the precipitates. Energy dispersive X-ray spectroscopy shows that the Ca/P ratio varies throughout the samples and resembles that of other bioinspired calcium phosphate hybrid materials. Elemental analysis shows that the carbon (i.e., polymer contents reach 10% in some samples, clearly illustrating the formation of a true hybrid material. Overall, the data indicate that a higher polymer concentration in the reaction mixture favors the formation of polymer-enriched materials, while lower polymer concentrations or high precursor concentrations favor the formation of products that are closely related to the control samples precipitated in the absence of polymer. The results thus highlight the potential of (water-soluble cellulose derivatives for the synthesis and design of bioinspired and bio-based hybrid materials.

  9. Biomimetic nanoparticles with polynucleotide and PEG mixed-monolayers enhance calcium phosphate mineralization

    Science.gov (United States)

    Vasconcellos, Kayla B.; McHugh, Sean M.; Dapsis, Katherine J.; Petty, Alexander R.; Gerdon, Aren E.

    2013-09-01

    Biomineralization of hydroxyapatite (Ca10(PO4)6(OH)2) is of significant importance in biomedical applications such as bone and dental repair, and biomimetic control of mineral formation may lead to more effective restorative procedures. Gold nanoparticles are functional scaffolds on which to assemble multi-component monolayers capable of mimicking protein activity in the templated synthesis of calcium phosphate. The goal of this research was to explore nanoparticle templates with mixed-monolayers of uncharged polar polyethylene glycol (PEG) molecules and highly charged polynucleotide and amino acid molecules in their ability to influence mineralization rates and mineral particle size and morphology. This research demonstrates through time-resolved optical density and dynamic light scattering measurements that the combination of tiopronin, PEG, and DNA presented on a nanoparticle surface decreases nanoparticle aggregation from 59 to 21 nm solvated radius, increases mineralization kinetics from 1.5 × 10-3 to 3.1 × 10-3 OD/min, and decreases mineral particle size from 685 to 442 nm average radius. FT-IR and TEM data demonstrate that mineralized material, while initially amorphous, transforms to a semi-crystalline material when guided by template interactions. This demonstrates that surface-tailored monolayer protected cluster scaffolds are successful and controllable mineralization templates with further potential for biomedical applications involving calcium phosphate and other biomaterials.

  10. Proteoliposomes as matrix vesicles' biomimetics to study the initiation of skeletal mineralization

    Directory of Open Access Journals (Sweden)

    A.M.S. Simão

    2010-03-01

    Full Text Available During the process of endochondral bone formation, chondrocytes and osteoblasts mineralize their extracellular matrix by promoting the formation of hydroxyapatite (HA seed crystals in the sheltered interior of membrane-limited matrix vesicles (MVs. Ion transporters control the availability of phosphate and calcium needed for HA deposition. The lipidic microenvironment in which MV-associated enzymes and transporters function plays a crucial physiological role and must be taken into account when attempting to elucidate their interplay during the initiation of biomineralization. In this short mini-review, we discuss the potential use of proteoliposome systems as chondrocyte- and osteoblast-derived MVs biomimetics, as a means of reconstituting a phospholipid microenvironment in a manner that recapitulates the native functional MV microenvironment. Such a system can be used to elucidate the interplay of MV enzymes during catalysis of biomineralization substrates and in modulating in vitro calcification. As such, the enzymatic defects associated with disease-causing mutations in MV enzymes could be studied in an artificial vesicular environment that better mimics their in vivo biological milieu. These artificial systems could also be used for the screening of small molecule compounds able to modulate the activity of MV enzymes for potential therapeutic uses. Such a nanovesicular system could also prove useful for the repair/treatment of craniofacial and other skeletal defects and to facilitate the mineralization of titanium-based tooth implants.

  11. 3D Biomimetic Magnetic Structures for Static Magnetic Field Stimulation of Osteogenesis

    Directory of Open Access Journals (Sweden)

    Irina Alexandra Paun

    2018-02-01

    Full Text Available We designed, fabricated and optimized 3D biomimetic magnetic structures that stimulate the osteogenesis in static magnetic fields. The structures were fabricated by direct laser writing via two-photon polymerization of IP-L780 photopolymer and were based on ellipsoidal, hexagonal units organized in a multilayered architecture. The magnetic activity of the structures was assured by coating with a thin layer of collagen-chitosan-hydroxyapatite-magnetic nanoparticles composite. In vitro experiments using MG-63 osteoblast-like cells for 3D structures with gradients of pore size helped us to find an optimum pore size between 20–40 µm. Starting from optimized 3D structures, we evaluated both qualitatively and quantitatively the effects of static magnetic fields of up to 250 mT on cell proliferation and differentiation, by ALP (alkaline phosphatase production, Alizarin Red and osteocalcin secretion measurements. We demonstrated that the synergic effect of 3D structure optimization and static magnetic stimulation enhances the bone regeneration by a factor greater than 2 as compared with the same structure in the absence of a magnetic field.

  12. 3D Biomimetic Magnetic Structures for Static Magnetic Field Stimulation of Osteogenesis.

    Science.gov (United States)

    Paun, Irina Alexandra; Popescu, Roxana Cristina; Calin, Bogdan Stefanita; Mustaciosu, Cosmin Catalin; Dinescu, Maria; Luculescu, Catalin Romeo

    2018-02-07

    We designed, fabricated and optimized 3D biomimetic magnetic structures that stimulate the osteogenesis in static magnetic fields. The structures were fabricated by direct laser writing via two-photon polymerization of IP-L780 photopolymer and were based on ellipsoidal, hexagonal units organized in a multilayered architecture. The magnetic activity of the structures was assured by coating with a thin layer of collagen-chitosan-hydroxyapatite-magnetic nanoparticles composite. In vitro experiments using MG-63 osteoblast-like cells for 3D structures with gradients of pore size helped us to find an optimum pore size between 20-40 µm. Starting from optimized 3D structures, we evaluated both qualitatively and quantitatively the effects of static magnetic fields of up to 250 mT on cell proliferation and differentiation, by ALP (alkaline phosphatase) production, Alizarin Red and osteocalcin secretion measurements. We demonstrated that the synergic effect of 3D structure optimization and static magnetic stimulation enhances the bone regeneration by a factor greater than 2 as compared with the same structure in the absence of a magnetic field.

  13. Embedded SMA wire actuated biomimetic fin: a module for biomimetic underwater propulsion

    International Nuclear Information System (INIS)

    Wang Zhenlong; Hang Guanrong; Wang Yangwei; Li Jian; Du Wei

    2008-01-01

    An embedded shape memory alloy (SMA) wire actuated biomimetic fin is presented, and based on this module for biomimetic underwater propulsion, a micro robot fish (146 mm in length, 30 g in weight) and a robot squid (242 mm in length, 360 g in weight) were developed. Fish swim by undulating their body and/or fins. Squid and cuttlefish can also swim by undulating their fins. To simplify engineering modeling, the undulating swimming movement is assumed to be the integration of the movements of many flexible bending segments connected in parallel or in series. According to this idea, a biomimetic fin which can bend flexibly was developed. The musculature of a cuttlefish fin was investigated to aid the design of the biomimetic fin. SMA wires act as 'muscle fibers' to drive the biomimetic fin just like the transverse muscles of the cuttlefish fin. During the bending phase, elastic energy is stored in the elastic substrate and skin, and during the return phase, elastic energy is released to power the return movement. Theorem analysis of the bending angle was performed to estimate the bending performance of the biomimetic fin. Experiments were carried out on single-face fins with latex rubber skin and silicone skin (SF-L and SF-S) to compare the bending angle, return time, elastic energy storage and reliability. Silicone was found to be the better skin. A dual-face fin with silicone skin (DF-S) was tested in water to evaluate the actuating performance and to validate the reliability. Thermal analysis of the SMA temperature was performed to aid the control strategy. The micro robot fish and robot squid employ one and ten DF-S, respectively. Swimming experiments with different actuation frequencies were carried out. The speed and steering radius of the micro robot fish reached 112 mm s −1 and 136 mm, respectively, and the speed and rotary speed of the robot squid reached 40 mm s −1 and 22° s −1 , respectively

  14. 2009 Clusters, Nanocrystals & Nanostructures GRC

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lai-Sheng [Washington State Univ., Pullman, WA (United States)

    2009-07-19

    For over thirty years, this Gordon Conference has been the premiere meeting for the field of cluster science, which studies the phenomena that arise when matter becomes small. During its history, participants have witnessed the discovery and development of many novel materials, including C60, carbon nanotubes, semiconductor and metal nanocrystals, and nanowires. In addition to addressing fundamental scientific questions related to these materials, the meeting has always included a discussion of their potential applications. Consequently, this conference has played a critical role in the birth and growth of nanoscience and engineering. The goal of the 2009 Gordon Conference is to continue the forward-looking tradition of this meeting and discuss the most recent advances in the field of clusters, nanocrystals, and nanostructures. As in past meetings, this will include new topics that broaden the field. In particular, a special emphasis will be placed on nanomaterials related to the efficient use, generation, or conversion of energy. For example, we anticipate presentations related to batteries, catalysts, photovoltaics, and thermoelectrics. In addition, we expect to address the controversy surrounding carrier multiplication with a session in which recent results addressing this phenomenon will be discussed and debated. The atmosphere of the conference, which emphasizes the presentation of unpublished results and lengthy discussion periods, ensures that attendees will enjoy a valuable and stimulating experience. Because only a limited number of participants are allowed to attend this conference, and oversubscription is anticipated, we encourage all interested researchers from academia, industry, and government institutions to apply as early as possible. An invitation is not required. We also encourage all attendees to submit their latest results for presentation at the poster sessions. We anticipate that several posters will be selected for 'hot topic' oral

  15. Biomimetics applied to centering in micro-assembly

    DEFF Research Database (Denmark)

    Shu, L.H.; Lenau, Torben Anker; Hansen, Hans Nørgaard

    2003-01-01

    This paper describes the application of a biomimetic search method to develop ideas for centering objects in micro-assembly. Biomimetics involves the imitation of biological phenomena to solve problems. An obstacle to the use of biomimetics in engineering is knowledge of biological phenomena...... that is relevant to the problem at hand. The method described here starts with an engineering problem, and then systematically searches for analogous biological phenomena using functional keywords. This method is illustrated by finding and using analogies for the problem of positioning and centering objects during...

  16. The state of the art in biomimetics

    International Nuclear Information System (INIS)

    Lepora, Nathan F; Prescott, Tony J; Verschure, Paul

    2013-01-01

    Biomimetics is a research field that is achieving particular prominence through an explosion of new discoveries in biology and engineering. The field concerns novel technologies developed through the transfer of function from biological systems. To analyze the impact of this field within engineering and related sciences, we compiled an extensive database of publications for study with network-based information analysis techniques. Criteria included publications by year and journal or conference, and subject areas judged by popular and common terms in titles. Our results reveal that this research area has expanded rapidly from less than 100 papers per year in the 1990s to several thousand papers per year in the first decade of this century. Moreover, this research is having impact across a variety of research themes, spanning robotics, computer science and bioengineering. In consequence, biomimetics is becoming a leading paradigm for the development of new technologies that will potentially lead to significant scientific, societal and economic impact in the near future. (perspective)

  17. Biomimetic devices functionalized by membrane channel proteins

    Science.gov (United States)

    Schmidt, Jacob

    2004-03-01

    We are developing a new family of active materials which derive their functional properties from membrane proteins. These materials have two primary components: the proteins and the membranes themselves. I will discuss our recent work directed toward development of a generic platform for a "plug-and-play" philosophy of membrane protein engineering. By creating a stable biomimetic polymer membrane a single molecular monolayer thick, we will enable the exploitation of the function of any membrane protein, from pores and pumps to sensors and energy transducers. Our initial work has centered on the creation, study, and characterization of the biomimetic membranes. We are attempting to make large areas of membrane monolayers using Langmuir-Blodgett film formation as well as through arrays of microfabricated black lipid membrane-type septa. A number of techniques allow the insertion of protein into the membranes. As a benchmark, we have been employing a model system of voltage-gated pore proteins, which have electrically controllable porosities. I will report on the progress of this work, the characterization of the membranes, protein insertion processes, and the yield and functionality of the composite.

  18. Assembling a Lasing Hybrid Material With Supramolecular Polymers and Nanocrystals

    National Research Council Canada - National Science Library

    Li, Leiming

    2003-01-01

    .... In the system containing ZnO nanocrystals as the inorganic component, both phases are oriented in the hybrid material forming an ultraviolet lasing medium with a lower threshold relative to pure ZnO nanocrystals.

  19. Surface treatment of nanocrystal quantum dots after film deposition

    Science.gov (United States)

    Sykora, Milan; Koposov, Alexey; Fuke, Nobuhiro

    2015-02-03

    Provided are methods of surface treatment of nanocrystal quantum dots after film deposition so as to exchange the native ligands of the quantum dots for exchange ligands that result in improvement in charge extraction from the nanocrystals.

  20. Synthesis and Characterization of Colloidal Metal and Photovoltaic Semiconductor Nanocrystals

    KAUST Repository

    Abulikemu, Mutalifu

    2014-01-01

    -performing photovoltaic nanocrystals contain toxic elements, such as Pb, or scarce elements, such as In; thus, the production of solution-processable nanocrystals from earth-abundant materials using environmentally benign synthesis and processing methods has become a

  1. Near-infrared light emitting device using semiconductor nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Supran, Geoffrey J.S.; Song, Katherine W.; Hwang, Gyuweon; Correa, Raoul Emile; Shirasaki, Yasuhiro; Bawendi, Moungi G.; Bulovic, Vladimir; Scherer, Jennifer

    2018-04-03

    A near-infrared light emitting device can include semiconductor nanocrystals that emit at wavelengths beyond 1 .mu.m. The semiconductor nanocrystals can include a core and an overcoating on a surface of the core.

  2. Light Scattering Spectroscopies of Semiconductor Nanocrystals (Quantum Dots)

    International Nuclear Information System (INIS)

    Yu, Peter Y; Gardner, Grat; Nozaki, Shinji; Berbezier, Isabelle

    2006-01-01

    We review the study of nanocrystals or quantum dots using inelastic light scattering spectroscopies. In particular recent calculations of the phonon density of states and low frequency Raman spectra in Ge nanocrystals are presented for comparison with experimental results

  3. Synthesis and Characterization of Hydroxyapatite/Fullerenol Nanocomposites.

    Science.gov (United States)

    Djordjevic, Aleksandar; Ignjatovic, Nenad; Seke, Mariana; Jovic, Danica; Uskokovic, Dragan; Rakocevic, Zlatko

    2015-02-01

    Fullerenols are polyhydroxylated, water soluble derivatives of fullerene C60, with potential application in medicine as diagnostic agents, antioxidants or nano drug carriers. This paper describes synthesis and physical characterization of a new nanocomposite hydroxyapatite/fullerenol. Surface of the nanocomposite hydroxyapatite/fullerenol is inhomogeneous with the diameter of the particles in the range from 100 nm to 350 nm. The ζ potential of this nanocomposite is ten times lower when compared to hydroxyapatite. Surface phosphate groups of hydroxyapatite are prone to forming hydrogen bonds, when in close contact with hydroxyl groups, which could lead to formation of hydrogen bonds between hydroxyapatite and hydroxyl groups of fullerenol. The surface of hydroxyapatite particles (-2.5 mV) was modified by fullerenol particles, as confirmed by the obtained ζ potential value of the nanocomposite biomaterial hydroxyapatite/fullerenol (-25.0 mV). Keywords: Hydroxyapatite, Fullerenol, Nanocomposite, Surface Analysis.

  4. The Effect of Zirconia in Hydroxyapatite on Staphylococcus epidermidis Growth

    Directory of Open Access Journals (Sweden)

    Widowati Siswomihardjo

    2012-01-01

    . Conclusion. The addition of zirconia into hydroxyapatite affected the growth of S. epidermidis. Hydroxyapatite with 20% zirconia proved to be an effective concentration to inhibit the growth of S. epidermidis colony.

  5. Sustained release of simvastatin from hollow carbonated hydroxyapatite microspheres prepared by aspartic acid and sodium dodecyl sulfate.

    Science.gov (United States)

    Wang, Ke; Wang, Yinjing; Zhao, Xu; Li, Yi; Yang, Tao; Zhang, Xue; Wu, Xiaoguang

    2017-06-01

    Hollow carbonated hydroxyapatite (HCHAp) microspheres as simvastatin (SV) sustained-release vehicles were fabricated through a novel and simple one-step biomimetic strategy. Firstly, hollow CaCO 3 microspheres were precipitated through the reaction of CaCl 2 with Na 2 CO 3 in the presence of aspartic acid and sodium dodecyl sulfate. Then, the as-prepared hollow CaCO 3 microspheres were transformed into HCHAp microspheres with a controlled anion-exchange method. The HCHAp microspheres were 3-5μm with a shell thickness of 0.5-1μm and were constructed of short needle nanoparticles. The HCHAp microspheres were then loaded with SV, exhibiting excellent drug-loading capacity and sustained release properties. These results present a new material synthesis strategy for HCHAp microspheres and suggest that the as-prepared HCHAp microspheres are promising for applications in drug delivery. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Scaffolds for bone regeneration made of hydroxyapatite microspheres in a collagen matrix

    Energy Technology Data Exchange (ETDEWEB)

    Cholas, Rahmatullah, E-mail: rahmat.cholas@gmail.com; Kunjalukkal Padmanabhan, Sanosh, E-mail: sanosh2001@gmail.com; Gervaso, Francesca; Udayan, Gayatri; Monaco, Graziana; Sannino, Alessandro; Licciulli, Antonio

    2016-06-01

    Biomimetic scaffolds with a structural and chemical composition similar to native bone tissue may be promising for bone tissue regeneration. In the present work hydroxyapatite mesoporous microspheres (mHA) were incorporated into collagen scaffolds containing an ordered interconnected macroporosity. The mHA were obtained by spray drying of a nano hydroxyapatite slurry prepared by the precipitation technique. X-ray diffraction (XRD) analysis revealed that the microspheres were composed only of hydroxyapatite (HA) phase, and energy-dispersive x-ray spectroscopy (EDS) analysis revealed the Ca/P ratio to be 1.69 which is near the value for pure HA. The obtained microspheres had an average diameter of 6 μm, a specific surface area of 40 m{sup 2}/g as measured by Brunauer-Emmett-Teller (BET) analysis, and Barrett-Joyner-Halenda (BJH) analysis showed a mesoporous structure with an average pore diameter of 16 nm. Collagen/HA-microsphere (Col/mHA) composite scaffolds were prepared by freeze-drying followed by dehydrothermal crosslinking. SEM observations of Col/mHA scaffolds revealed HA microspheres embedded within a porous collagen matrix with a pore size ranging from a few microns up to 200 μm, which was also confirmed by histological staining of sections of paraffin embedded scaffolds. The compressive modulus of the composite scaffold at low and high strain values was 1.7 and 2.8 times, respectively, that of pure collagen scaffolds. Cell proliferation measured by the MTT assay showed more than a 3-fold increase in cell number within the scaffolds after 15 days of culture for both pure collagen scaffolds and Col/mHA composite scaffolds. Attractive properties of this composite scaffold include the potential to load the microspheres for drug delivery and the controllability of the pore structure at various length scales. - Highlights: • Mesoporous hydroxyapatite microsphere(mHA) synthesized by spray drying method • Porous collagen/mHA composite scaffold made by freeze

  7. Nanocrystal Bioassembly: Asymmetry, Proximity, and Enzymatic Manipulation

    Energy Technology Data Exchange (ETDEWEB)

    Claridge, Shelley A. [Univ. of California, Berkeley, CA (United States)

    2008-05-01

    Research at the interface between biomolecules and inorganic nanocrystals has resulted in a great number of new discoveries. In part this arises from the synergistic duality of the system: biomolecules may act as self-assembly agents for organizing inorganic nanocrystals into functional materials; alternatively, nanocrystals may act as microscopic or spectroscopic labels for elucidating the behavior of complex biomolecular systems. However, success in either of these functions relies heavily uponthe ability to control the conjugation and assembly processes.In the work presented here, we first design a branched DNA scaffold which allows hybridization of DNA-nanocrystal monoconjugates to form discrete assemblies. Importantly, the asymmetry of the branched scaffold allows the formation of asymmetric2assemblies of nanocrystals. In the context of a self-assembled device, this can be considered a step toward the ability to engineer functionally distinct inputs and outputs.Next we develop an anion-exchange high performance liquid chromatography purification method which allows large gold nanocrystals attached to single strands of very short DNA to be purified. When two such complementary conjugates are hybridized, the large nanocrystals are brought into close proximity, allowing their plasmon resonances to couple. Such plasmon-coupled constructs are of interest both as optical interconnects for nanoscale devices and as `plasmon ruler? biomolecular probes.We then present an enzymatic ligation strategy for creating multi-nanoparticle building blocks for self-assembly. In constructing a nanoscale device, such a strategy would allow pre-assembly and purification of components; these constructs can also act as multi-label probes of single-stranded DNA conformational dynamics. Finally we demonstrate a simple proof-of-concept of a nanoparticle analog of the polymerase chain reaction.

  8. Biomimetics materials, structures and processes : examples, ideas and case studies

    CERN Document Server

    Bruckner, Dietmar; Hellmich, Christian; Schmiedmayer, Heinz-Bodo; Stachelberger, Herbert; Gebeshuber, Ille

    2011-01-01

    The book presents an outline of current activities in the field of biomimetics and integrates a variety of applications comprising biophysics, surface sciences, architecture and medicine. Biomimetics as innovation method is characterised by interdisciplinary information transfer from the life sciences to technical application fields aiming at increased performance, functionality and energy efficiency. The contributions of the book relate to the research areas: - Materials and structures in nanotechnology and biomaterials - Biomimetic approaches to develop new forms, construction principles and design methods in architecture - Information and dynamics in automation, neuroinformatics and biomechanics Readers will be informed about the latest research approaches and results in biomimetics with examples ranging from bionic nano-membranes to function-targeted design of tribological surfaces and the translation of natural auditory coding strategies.

  9. Biomimetic Structural Materials: Inspiration from Design and Assembly.

    Science.gov (United States)

    Yaraghi, Nicholas A; Kisailus, David

    2018-04-20

    Nature assembles weak organic and inorganic constituents into sophisticated hierarchical structures, forming structural composites that demonstrate impressive combinations of strength and toughness. Two such composites are the nacre structure forming the inner layer of many mollusk shells, whose brick-and-mortar architecture has been the gold standard for biomimetic composites, and the cuticle forming the arthropod exoskeleton, whose helicoidal fiber-reinforced architecture has only recently attracted interest for structural biomimetics. In this review, we detail recent biomimetic efforts for the fabrication of strong and tough composite materials possessing the brick-and-mortar and helicoidal architectures. Techniques discussed for the fabrication of nacre- and cuticle-mimetic structures include freeze casting, layer-by-layer deposition, spray deposition, magnetically assisted slip casting, fiber-reinforced composite processing, additive manufacturing, and cholesteric self-assembly. Advantages and limitations to these processes are discussed, as well as the future outlook on the biomimetic landscape for structural composite materials.

  10. Biomimetic Structural Materials: Inspiration from Design and Assembly

    Science.gov (United States)

    Yaraghi, Nicholas A.; Kisailus, David

    2018-04-01

    Nature assembles weak organic and inorganic constituents into sophisticated hierarchical structures, forming structural composites that demonstrate impressive combinations of strength and toughness. Two such composites are the nacre structure forming the inner layer of many mollusk shells, whose brick-and-mortar architecture has been the gold standard for biomimetic composites, and the cuticle forming the arthropod exoskeleton, whose helicoidal fiber-reinforced architecture has only recently attracted interest for structural biomimetics. In this review, we detail recent biomimetic efforts for the fabrication of strong and tough composite materials possessing the brick-and-mortar and helicoidal architectures. Techniques discussed for the fabrication of nacre- and cuticle-mimetic structures include freeze casting, layer-by-layer deposition, spray deposition, magnetically assisted slip casting, fiber-reinforced composite processing, additive manufacturing, and cholesteric self-assembly. Advantages and limitations to these processes are discussed, as well as the future outlook on the biomimetic landscape for structural composite materials.

  11. Biomimetic Designs Inspired by Seashells-Seashells Helping ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 17; Issue 6. Biomimetic Designs Inspired by Seashells - Seashells Helping Engineers Design Better Ceramics. Kiran Akella. General Article Volume 17 Issue 6 June 2012 pp 573-591 ...

  12. A review paper on biomimetic calcium phosphate coatings

    NARCIS (Netherlands)

    Lin, X.; de Groot, K.; Wang, D.; Hu, Q.; Wismeijer, D.; Liu, Y.

    2015-01-01

    Biomimetic calcium phosphate coatings have been developed for bone regeneration and repair because of their biocompatibility, osteoconductivity, and easy preparation. They can be rendered osteoinductive by incorporating an osteogenic agent, such as bone morphogenetic protein 2 (BMP-2), into the

  13. Biomimetic Composite Scaffold for Breast Reconstruction Following Tumor Resection

    National Research Council Canada - National Science Library

    Patrick, Jr, Charles W

    2005-01-01

    ... of life and outcomes are markedly improved. We hypothesized that a novel composite material consisting of silk fibroin and chitosan will act as a biomimetic scaffold amenable to in vivo adipogenesis. The specific aims (SAs...

  14. Cellulose nanocrystal: electronically conducting polymer nanocomposites for supercapacitors

    OpenAIRE

    Liew, Soon Yee

    2012-01-01

    This thesis describes the use of cellulose nanocrystals for the fabrication of porous nanocomposites with electronic conducting polymers for electrochemical supercapacitor applications. The exceptional strength and negatively charged surface functionalities on cellulose nanocrystals are utilised in these nanocomposites. The negatively charged surface functionalities on cellulose nanocrystals allow their simultaneous incorporation into electropolymerised, positively charged conducting polymer ...

  15. Biofouling and Design of a Biomimetic Hull-Grooming Tool

    Science.gov (United States)

    2007-09-14

    have barred the use of organotin compounds such as tributyltin ( TBT ) and copper-based paints, which are currently used by the Navy and have become...copper into the water, killing the fouling organisms. There is new research in biomimetic polymers that deter fouling, but are non- toxic . These polymers...is new research in biomimetic polymers that deter fouling, but are non- toxic . These polymers are rigidly attached to the hull surface extending

  16. Small Molecule and Polymer Effects on Bio-mimetic Sensors

    OpenAIRE

    Garcia, Ignacio J.; Branan, Nicole; Wells, Todd A.

    2005-01-01

    Formation of biomimetic membranes for the purpose of producing a protein based infrared biosensor has proven to be a difficult obstacle. Several methods have been employed and reproducibility is becoming more frequent. The use of polystyrene as an adhesion layer between the biomimetic and diamond surfaces is the most reliable form of reproducibility yet encountered. Unique properties of acetylcholine esterase based biosensors include infrared absorption bands that are not present in either th...

  17. Characterisation of Suspension Precipitated Nanocrystalline Hydroxyapatite Powders

    International Nuclear Information System (INIS)

    Mallik, P K; Swain, P.K.; Patnaik, S.C

    2016-01-01

    Hydroxyapatite (HA) is a well-known biomaterial for coating on femoral implants, filling of dental cavity and scaffold for tissue replacement. Hydroxyapatite possess limited load bearing capacity due to their brittleness. In this paper, the synthesis of nanocrystalline hydroxyapatite powders was prepared by dissolving calcium oxide in phosphoric acid, followed by addition of ammonia liquor in a beaker. The prepared solution was stirred by using magnetic stirrer operated at temperature of 80°C for an hour. This leads to the formation of hydroxyapatite precipitate. The precipitate was dried in oven for overnight at 100°C. The dried agglomerated precipitate was calcined at 800°C in conventional furnace for an hour. The influence of calcium oxide concentration and pH on the resulting precipitates was studied using BET, XRD and SEM. As result, a well-defined sub-rounded morphology of powders size of ∼41 nm was obtained with a salt concentration of 0.02 M. Finally, it can be concluded that small changes in the reaction conditions led to large changes in final size, shape and degree of aggregation of the hydroxyapatite particles. (paper)

  18. Continuous microwave flow synthesis of mesoporous hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Akram, Muhammad; Alshemary, Ammar Z.; Goh, Yi-Fan; Wan Ibrahim, Wan Aini [Department of Chemistry, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Lintang, Hendrik O. [Centre for Sustainable Nanomaterials (CSNano), Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Hussain, Rafaqat, E-mail: rafaqat@kimia.fs.utm.my [Centre for Sustainable Nanomaterials (CSNano), Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia)

    2015-11-01

    We have successfully used continuous microwave flow synthesis (CMFS) technique for the template free synthesis of mesoporous hydroxyapatite. The continuous microwave flow reactor consisted of a modified 2.45 GHz household microwave, peristaltic pumps and a Teflon coil. This cost effective and efficient system was exploited to produce semi-crystalline phase pure nano-sized hydroxyapatite. Effect of microwave power, retention time and the concentration of reactants on the phase purity, degree of crystallinity and surface area of the final product was studied in detail. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to study the phase purity and composition of the product, while transmission electron microscopy (TEM) was used to study the effect of process parameters on the morphology of hydroxyapatite. The TEM analysis confirmed the formation of spherical particles at low microwave power; however the morphology of the particles changed to mesoporous needle and rod-like structure upon exposing the reaction mixture to higher microwave power and longer retention time inside the microwave. The in-vitro ion dissolution behavior of the as synthesized hydroxyapatite was studied by determining the amount of Ca{sup 2+} ion released in SBF solution. - Highlights: • Continuous microwave flow synthesis method was used to prepare hydroxyapatite. • Increase in microwave power enhanced the degree of crystallinity. • TEM images confirmed the presence of mesopores on the surface of HA.

  19. Continuous microwave flow synthesis of mesoporous hydroxyapatite

    International Nuclear Information System (INIS)

    Akram, Muhammad; Alshemary, Ammar Z.; Goh, Yi-Fan; Wan Ibrahim, Wan Aini; Lintang, Hendrik O.; Hussain, Rafaqat

    2015-01-01

    We have successfully used continuous microwave flow synthesis (CMFS) technique for the template free synthesis of mesoporous hydroxyapatite. The continuous microwave flow reactor consisted of a modified 2.45 GHz household microwave, peristaltic pumps and a Teflon coil. This cost effective and efficient system was exploited to produce semi-crystalline phase pure nano-sized hydroxyapatite. Effect of microwave power, retention time and the concentration of reactants on the phase purity, degree of crystallinity and surface area of the final product was studied in detail. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to study the phase purity and composition of the product, while transmission electron microscopy (TEM) was used to study the effect of process parameters on the morphology of hydroxyapatite. The TEM analysis confirmed the formation of spherical particles at low microwave power; however the morphology of the particles changed to mesoporous needle and rod-like structure upon exposing the reaction mixture to higher microwave power and longer retention time inside the microwave. The in-vitro ion dissolution behavior of the as synthesized hydroxyapatite was studied by determining the amount of Ca 2+ ion released in SBF solution. - Highlights: • Continuous microwave flow synthesis method was used to prepare hydroxyapatite. • Increase in microwave power enhanced the degree of crystallinity. • TEM images confirmed the presence of mesopores on the surface of HA

  20. Biomineralization-inspired synthesis of chitosan/hydroxyapatite biocomposites based on a novel bilayer rate-controlling model.

    Science.gov (United States)

    Hu, Jing-Xiao; Ran, Jia-Bing; Chen, Si; Shen, Xin-Yu; Tong, Hua

    2015-12-01

    In order to prepare sophisticated biomaterials using a biomimetic approach, a deeper understanding of biomineralization is needed. Of particular importance is the control and regulation of the mineralization process. In this study, a novel bilayer rate-controlling model was designed to investigate the factors potentially influencing mineralization. In the absence of a rate-controlling layer, nano-scale hydroxyapatite (HA) crystallites exhibited a spherical morphology, whereas, in the presence of a rate-controlling layer, HA crystallites were homogeneously dispersed and spindle-like in structure. The mineralization rate had a significant effect on controlling the morphology of crystals. Furthermore, in vitro tests demonstrated that the reaction layer containing spindle-like HA crystallites possessed superior biological properties. These results suggest that a slow mineralization rate is required for controlling the morphology of inorganic crystallites, and consumption by the rate-controlling layer ensured that the ammonia concentration remained low. This study demonstrates that a biomimetic approach can be used to prepare novel biomaterials containing HA crystallites that have different morphologies and biological properties. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Growth of hydroxyapatite on the cellular membrane of the bacterium Bacillus thuringiensis for the preparation of hybrid biomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Cervantes, Eric Reyes, E-mail: onomaeric@hotmail.com [Centro de Investigación en Ciencias Microbiológicas, Benemérita Universidad Autónoma de Puebla, Prolongación de la 24 Sur y Ave San Claudio, Ciudad Universitaria, Col San Manuel, C.P. 72570 Puebla, Pue (Mexico); Torres, Maykel González, E-mail: mikegcu@fata.unam.mx [Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, Campus Juriquilla, Boulevard Juriquilla 3001, Santiago de Querétaro, Querétaro C.P. 76230 (Mexico); Muñoz, Susana Vargas, E-mail: vmsu@unam.mx [Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, Campus Juriquilla, Boulevard Juriquilla 3001, Santiago de Querétaro, Querétaro C.P. 76230 (Mexico); Rosas, Efraín Rubio, E-mail: efrainrubio@yahoo.com [Centro de Investigación en Ciencias Microbiológicas, Benemérita Universidad Autónoma de Puebla, Prolongación de la 24 Sur y Ave San Claudio, Ciudad Universitaria, Col San Manuel, C.P. 72570 Puebla, Pue (Mexico); and others

    2016-01-01

    This study aimed to grow hydroxyapatite (HAp) crystals on the cellular wall of the Gram-positive bacterium Bacillus thuringiensis using a bio-mimetic method. Several strains were phenotypically and genotypically characterized using multilocus sequence typing (MLST) gene markers to differentiate the strains and confirm the identity of the isolated species to guarantee that the selected species was not harmful to human health or the environment. Three of the analyzed strains were selected because they exhibited the best nucleation and growth of HAp on the bacterial surface. This innovative method to grow HAp crystals on a cellular membrane helps to elucidate the mechanisms by which osseous tissue is formed in nature. The optimum concentration for the simulated physiological fluid (SPF) was 1.5 ×. The hybrid materials were characterized by optical microscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). - Highlights: • HAp crystals are grown on the cellular wall of a GP bacteria Bacillus thuringiensis. • The growing was carried out by using a bio-mimetic method. • Hybrid materials were characterized with morphological and spectroscopic techniques. • The reported method allows understanding the mechanisms to produce osseous tissue. • The membrane of Bacillus thuringiensis can grow more HAp than Bacillus halodurans.

  2. Biomimetic Membrane Arrays on Cast Hydrogel Supports

    DEFF Research Database (Denmark)

    Roerdink-Lander, Monique; Ibragimova, Sania; Rein Hansen, Christian

    2011-01-01

    , provides mechanical support but at the cost of small molecule transport through the membrane−support sandwich. To stabilize biomimetic membranes while allowing transport through a membrane−support sandwich, we have investigated the feasibility of using an ethylene tetrafluoroethylene (ETFE......)/hydrogel sandwich as the support. The sandwich is realized as a perforated surface-treated ETFE film onto which a hydrogel composite support structure is cast. We report a simple method to prepare arrays of lipid bilayer membranes with low intrinsic electrical conductance on the highly permeable, self......-supporting ETFE/hydrogel sandwiches. We demonstrate how the ETFE/hydrogel sandwich support promotes rapid self-thinning of lipid bilayers suitable for hosting membrane-spanning proteins....

  3. Biomimetic polymeric membranes for water treatment

    DEFF Research Database (Denmark)

    Habel, Joachim Erich Otto

    This project is about the interplay of the three major components of aquaporin based biomimetic polymeric membranes (ABPMs): Aquaporins (AQPs), amphiphilic block copolymers, serving as a vesicular matrix for the hydrophobic AQP exterior (proteopolymersomes) and a polymeric membrane as embedment....... The interplay of proteopolymersomes and polymeric mesh support (in this case polyethersulfone, PES) was examined via integration of proteopolymersomes in an active layer (AL) formed by interfacial polymerisation between a linker molecule in aqueous phase and another in organic phase on top of the PES....... The resulting thin-film composite (TFC) membrane was analyzed via cross-flow forward osmosis (FO), scanning electron microscopy (SEM), fourier-transformed infrared spectroscopy (FTIR), as well as in the non-supported form over FTIR and a specialized microfluidic visualization approach. Where no clear dierences...

  4. Electrochemical characterization of hydrogels for biomimetic applications

    DEFF Research Database (Denmark)

    Peláez, L.; Romero, V.; Escalera, S.

    2011-01-01

    ) or a photoinitiator (P) to encapsulate and stabilize biomimetic membranes for novel separation technologies or biosensor applications. In this paper, we have investigated the electrochemical properties of the hydrogels used for membrane encapsulation. Specifically, we studied the crosslinked hydrogels by using...... electrochemical impedance spectroscopy (EIS), and we demonstrated that chemically crosslinked hydrogels had lower values for the effective electrical resistance and higher values for the electrical capacitance compared with hydrogels with photoinitiated crosslinking. Transport numbers were obtained using......〉 and 〈Pw〉 values than PEG‐1000‐DMA‐P and PEG‐400‐DA‐P hydrogels. In conclusion, our results show that hydrogel electrochemical properties can be controlled by the choice of polymer and type of crosslinking used and that their water and salt permeability properties are congruent with the use of hydrogels...

  5. Biomimetics for architecture & design nature, analogies, technology

    CERN Document Server

    Pohl, Göran

    2015-01-01

    This book provides the readers with a timely guide to the application of biomimetic principles in architecture and engineering design. As a result of a combined effort by two internationally recognized authorities, the biologist Werner Nachtigall and the architect Göran Pohl, the book describes the principles which can be used to compare nature and technology, and at the same time it presents detailed explanations and examples showing how biology can be used as a source of inspiration and “translated” in building and architectural solutions (biomimicry). Even though nature cannot be directly copied, the living world can provide architects and engineers with a wealth of analogues and inspirations for their own creative designs. But how can analysis of natural entities give rise to advanced and sustainable design? By reporting on the latest bionic design methods and using extensive artwork, the book guides readers through the field of nature-inspired architecture, offering an extraordinary resource for pro...

  6. Biomimetic electrospun nanofibers for tissue regeneration

    International Nuclear Information System (INIS)

    Liao, Susan; Li Bojun; Ma Zuwei; Wei He; Chan Casey; Ramakrishna, Seeram

    2006-01-01

    Nanofibers exist widely in human tissue with different patterns. Electrospinning nanotechnology has recently gained a new impetus due to the introduction of the concept of biomimetic nanofibers for tissue regeneration. The advanced electrospinning technique is a promising method to fabricate a controllable continuous nanofiber scaffold similar to the natural extracellular matrix. Thus, the biomedical field has become a significant possible application field of electrospun fibers. Although electrospinning has developed rapidly over the past few years, electrospun nanofibers are still at a premature research stage. Further comprehensive and deep studies on electrospun nanofibers are essential for promoting their biomedical applications. Current electrospun fiber materials include natural polymers, synthetic polymers and inorganic substances. This review briefly describes several typically electrospun nanofiber materials or composites that have great potential for tissue regeneration, and describes their fabrication, advantages, drawbacks and future prospects. (topical review)

  7. Biomimetic artificial sphincter muscles: status and challenges

    Science.gov (United States)

    Leung, Vanessa; Fattorini, Elisa; Karapetkova, Maria; Osmani, Bekim; Töpper, Tino; Weiss, Florian; Müller, Bert

    2016-04-01

    Fecal incontinence is the involuntary loss of bowel content and affects more than 12% of the adult population, including 45% of retirement home residents. Severe fecal incontinence is often treated by implanting an artificial sphincter. Currently available implants, however, have long-term reoperation rates of 95% and definitive explantation rates of 40%. These statistics show that the implants fail to reproduce the capabilities of the natural sphincter and that the development of an adaptive, biologically inspired implant is required. Dielectric elastomer actuators (DEA) are being developed as artificial muscles for a biomimetic sphincter, due to their suitable response time, reaction forces, and energy consumption. However, at present the operation voltage of DEAs is too high for artificial muscles implanted in the human body. To reduce the operating voltage to tens of volts, we are using microfabrication to reduce the thickness of the elastomer layer to the nanometer level. Two microfabrication methods are being investigated: molecular beam deposition and electrospray deposition. This communication covers the current status and a perspective on the way forward, including the long-term prospects of constructing a smart sphincter from low-voltage sensors and actuators based on nanometer-thin dielectric elastomer films. As DEA can also provide sensory feedback, a biomimetic sphincter can be designed in accordance with the geometrical and mechanical parameters of its natural counterpart. The availability of such technology will enable fast pressure adaption comparable to the natural feedback mechanism, so that tissue atrophy and erosion can be avoided while maintaining continence du ring daily activities.

  8. Biomimetic oral mucin from polymer micelle networks

    Science.gov (United States)

    Authimoolam, Sundar Prasanth

    Mucin networks are formed by the complexation of bottlebrush-like mucin glycoprotein with other small molecule glycoproteins. These glycoproteins create nanoscale strands that then arrange into a nanoporous mesh. These networks play an important role in ensuring surface hydration, lubricity and barrier protection. In order to understand the functional behavior in mucin networks, it is important to decouple their chemical and physical effects responsible for generating the fundamental property-function relationship. To achieve this goal, we propose to develop a synthetic biomimetic mucin using a layer-by-layer (LBL) deposition approach. In this work, a hierarchical 3-dimensional structures resembling natural mucin networks was generated using affinity-based interactions on synthetic and biological surfaces. Unlike conventional polyelectrolyte-based LBL methods, pre-assembled biotin-functionalized filamentous (worm-like) micelles was utilized as the network building block, which from complementary additions of streptavidin generated synthetic networks of desired thickness. The biomimetic nature in those synthetic networks are studied by evaluating its structural and bio-functional properties. Structurally, synthetic networks formed a nanoporous mesh. The networks demonstrated excellent surface hydration property and were able capable of microbial capture. Those functional properties are akin to that of natural mucin networks. Further, the role of synthetic mucin as a drug delivery vehicle, capable of providing localized and tunable release was demonstrated. By incorporating antibacterial curcumin drug loading within synthetic networks, bacterial growth inhibition was also demonstrated. Thus, such bioactive interfaces can serve as a model for independently characterizing mucin network properties and through its role as a drug carrier vehicle it presents exciting future opportunities for localized drug delivery, in regenerative applications and as bio

  9. Hydrothermal synthesis of tungsten doped tin dioxide nanocrystals

    Science.gov (United States)

    Zhou, Cailong; Li, Yufeng; Chen, Yiwen; Lin, Jing

    2018-01-01

    Tungsten doped tin dioxide (WTO) nanocrystals were synthesized through a one-step hydrothermal method. The structure, composition and morphology of WTO nanocrystals were characterized by x-ray diffraction, x-ray photoelectron spectroscopy, energy dispersive x-ray spectroscopy, UV-vis diffuse reflectance spectra, zeta potential analysis and high-resolution transmission electron microscopy. Results show that the as-prepared WTO nanocrystals were rutile-type structure with the size near 13 nm. Compared with the undoped tin dioxide nanocrystals, the WTO nanocrystals possessed better dispersity in ethanol phase and formed transparent sol.

  10. Finite Element Simulation of Diametral Strength Test of Hydroxyapatite

    International Nuclear Information System (INIS)

    Ozturk, Fahrettin; Toros, Serkan; Evis, Zafer

    2011-01-01

    In this study, the diametral strength test of sintered hydroxyapatite was simulated by the finite element software, ABAQUS/Standard. Stress distributions on diametral test sample were determined. The effect of sintering temperature on stress distribution of hydroxyapatite was studied. It was concluded that high sintering temperatures did not reduce the stress on hydroxyapatite. It had a negative effect on stress distribution of hydroxyapatite after 1300 deg. C. In addition to the porosity, other factors (sintering temperature, presence of phases and the degree of crystallinity) affect the diametral strength of the hydroxyapatite.

  11. Biomimetic and Aggregation-Driven Crystallization Route for Room-Temperature Material Synthesis: Growth of β-Ga2O3 Nanoparticles Using Peptide Assemblies as Nanoreactors

    Science.gov (United States)

    Lee, Sang-Yup; Gao, Xueyun; Matsui, Hiroshi

    2008-01-01

    The room temperature synthesis of β-Ga2O3 nanocrystal was examined by coupling two biomimetic crystallization techniques, the enzymatic peptide nano-assembly templating and the aggregation-driven crystallization. The catalytic template of peptide assembly nucleated and mineralized primary β-Ga2O3 crystals, and then fused them to grow single-crystalline and monodisperse nanoparticles in the cavity of the peptide assembly at room temperature. In this work, the peptide assembly was exploited as a nano-reactor with an enzymatic functionality catalyzing the hydrolysis of gallium precursors. In addition, the characteristic ring-structure of peptide assembly is expected to provide an efficient dehydration pathway and the crystallization control over the surface tension, which are advantageous for the β-Ga2O3 crystal growth. This multifunctional peptide assembly could be applied for syntheses of a variety of nanomaterials that are kinetically difficult to grow at room temperature. PMID:17302413

  12. Crystallization and Growth of Colloidal Nanocrystals

    CERN Document Server

    Leite, Edson Roberto

    2012-01-01

    Since the size, shape, and microstructure of nanocrystalline materials strongly impact physical and chemical properties, the development of new synthetic routes to  nanocrystals with controlled composition and morphology is a key objective of the nanomaterials community. This objective is dependent on control of the nucleation and growth mechanisms that occur during the synthetic process, which in turn requires a fundamental understanding of both classical nucleation and growth and non-classical growth processes in nanostructured materials.  Recently, a novel growth process called Oriented Attachment (OA) was identified which appears to be a fundamental mechanism during the development of nanoscale  materials. OA is a special case of aggregation that provides an important route by which nanocrystals grow, defects are formed, and unique—often symmetry-defying—crystal morphologies can be produced. This growth mechanism involves reversible self-assembly of primary nanocrystals followed by reorientati...

  13. Shaping metal nanocrystals through epitaxial seeded growth

    Energy Technology Data Exchange (ETDEWEB)

    Habas, Susan E.; Lee, Hyunjoo; Radmilovic, Velimir; Somorjai,Gabor A.; Yang, Peidong

    2008-02-17

    Morphological control of nanocrystals has becomeincreasingly important, as many of their physical and chemical propertiesare highly shape-dependent. Nanocrystal shape control for both single andmultiple material systems, however, remains fairly empirical andchallenging. New methods need to be explored for the rational syntheticdesign of heterostructures with controlled morphology. Overgrowth of adifferent material on well-faceted seeds, for example, allows for the useof the defined seed morphology to control nucleation and growth of thesecondary structure. Here, we have used highly faceted cubic Pt seeds todirect the epitaxial overgrowth of a secondary metal. We demonstrate thisconcept with lattice matched Pd to produce conformal shape-controlledcore-shell particles, and then extend it to lattice mismatched Au to giveanisotropic growth. Seeding with faceted nanocrystals may havesignificant potential towards the development of shape-controlledheterostructures with defined interfaces.

  14. The structure and morphology of semiconductor nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Kadavanich, Andreas V. [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry

    1997-11-01

    Colloidal semiconductor nanocrystals were studied using High Resolution Transmission Electron Microscopy (HRTEM). Organically capped nanocrystals were found to have faceted shapes consistent with Wulff polyhedra after the effects of capping ligands on surface energies were taken into account. The basic shape thus derived for wurtzite (WZ) structure CdSe nanocrystals capped by tri-octyl phosphine oxide (TOPO) was a truncated hexagonal prism, elongated alone the <001> axis with (100) and (002) facets. This structure has C{sub 3v} point group symmetry. The main defect in this structure is a stacking fault (a single layer of zinc blende type stacking), which does not significantly affect the shape (does not alter the point group).

  15. Strained interface defects in silicon nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Benjamin G.; Stradins, Paul [National Center for Photovoltaics, National Renewable Energy Laboratory, Golden, CO (United States); Hiller, Daniel; Zacharias, Margit [IMTEK - Faculty of Engineering, Albert-Ludwigs-University Freiburg (Germany); Luo, Jun-Wei; Beard, Matthew C. [Chemical and Materials Science, National Renewable Energy Laboratory, Golden, CO (United States); Semonin, Octavi E. [Chemical and Materials Science, National Renewable Energy Laboratory, Golden, CO (United States); Department of Physics, University of Colorado, Boulder, CO (United States)

    2012-08-07

    The surface of silicon nanocrystals embedded in an oxide matrix can contain numerous interface defects. These defects strongly affect the nanocrystals' photoluminescence efficiency and optical absorption. Dangling-bond defects are nearly eliminated by H{sub 2} passivation, thus decreasing absorption below the quantum-confined bandgap and enhancing PL efficiency by an order of magnitude. However, there remain numerous other defects seen in absorption by photothermal deflection spectroscopy; these defects cause non-radiative recombination that limits the PL efficiency to <15%. Using atomistic pseudopotential simulations, we attribute these defects to two specific types of distorted bonds: Si-Si and bridging Si-O-Si bonds between two Si atoms at the nanocrystal surface. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Developing New Nanoprobes from Semiconductor Nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Aihua [Univ. of California, Berkeley, CA (United States)

    2006-01-01

    In recent years, semiconductor nanocrystal quantum dots havegarnered the spotlight as an important new class of biological labelingtool. Withoptical properties superior to conventional organicfluorophores from many aspects, such as high photostability andmultiplexing capability, quantum dots have been applied in a variety ofadvanced imaging applications. This dissertation research goes along withlarge amount of research efforts in this field, while focusing on thedesign and development of new nanoprobes from semiconductor nanocrystalsthat are aimed for useful imaging or sensing applications not possiblewith quantum dots alone. Specifically speaking, two strategies have beenapplied. In one, we have taken advantage of the increasing capability ofmanipulating the shape of semiconductor nanocrystals by developingsemiconductor quantum rods as fluorescent biological labels. In theother, we have assembled quantum dots and gold nanocrystals into discretenanostructures using DNA. The background information and synthesis,surface manipulation, property characterization and applications of thesenew nanoprobes in a few biological experiments are detailed in thedissertation.

  17. Characterization of hydroxyapatite substituted with silicon

    International Nuclear Information System (INIS)

    Silva, H.M. da; Soares, G.A.; Mateescu, M.; Anselme, K.; Palard, M.; Champion, E.

    2009-01-01

    Incorporation of silicon (Si) ions into hydroxyapatite structure (HA) influences on physical, chemical and physiological properties. Some studies reported the improved bioactivity Si substitution, and it also accelerates the biomineralization process. The main objective of this work is to characterize stoichiometric hydroxyapatite and hydroxyapatite substituted with 1.13% in weight of Si (SiHA) using a wet precipitation method followed by a heat treatment. SEM/EDS, AFM, DRX and FTIR analyses were used to characterize the samples. EDS and FTIR results confirmed the presence of Si. Silicon induces small changes on crystal structure of HA, not detected on X-ray diffraction patterns of sintered tablets of SiHA and HA. No secondary phases were observed, that indicates the Si had entered the HA lattice. (author)

  18. Bone-like hydroxyapatite precipitated from 10×SBF-like solution by microwave irradiation

    International Nuclear Information System (INIS)

    Tolga Demirtaş, T.; Kaynak, Gökçe; Gümüşderelioğlu, Menemşe

    2015-01-01

    Microwave-assisted methods have been frequently used in many processes owing to their numerous advantages such as performing fast, efficient and homogenous processes and reducing side reactions. In view of these benefits, in this study it was purposed to produce bone-like hydroxyapatite (HA) by inducing biomimetic process with microwave-irradiation. This is why, concentrated body fluid (SBF) i.e. 10×SBF-like solution was used and it was precipitated in different microwave powers i.e. 90 W, 360 W, 600 W, and 1200 W and in different exposure times. For comparison, precipitation process was also carried out at room temperature for 6 h and at 80 °C for 1 h. The obtained HA structures were characterized by appropriate instrumental techniques. As a result, microwave-induced precipitation at 600 W for 9 times 30 s was determined as the optimum condition for the production of HA which has similar properties to the cortical bone. At this condition, B-type HA with 9.22% (wt.) carbonate content, 1.61 Ca/P molar ratio and amorphous structure was obtained easily, rapidly and efficiently. So, this is the first time microwave technology has been used to precipitate HA from SBF solution. - Highlights: • Simple, rapid and efficient method was developed to produce bone-like HA. • Microwave radiation and biomimetic approach via 10×SBF-like solution were combined. • Microwave irradiation at 600 W for 9 × 30 s was determined as the optimum condition. • B-type HA (carbonate content: 9.22%; 1.61 Ca/P:1.61; amorph) was produced. • This method may be employed for the effective HA coating of 3D bone scaffolds

  19. Bone-like hydroxyapatite precipitated from 10×SBF-like solution by microwave irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Tolga Demirtaş, T.; Kaynak, Gökçe [Bioengineering Engineering Department, Hacettepe University, 06800 Beytepe, Ankara (Turkey); Gümüşderelioğlu, Menemşe, E-mail: menemse@hacettepe.edu.tr [Bioengineering Engineering Department, Hacettepe University, 06800 Beytepe, Ankara (Turkey); Chemical Engineering Department, Hacettepe University, 06800 Beytepe, Ankara (Turkey)

    2015-04-01

    Microwave-assisted methods have been frequently used in many processes owing to their numerous advantages such as performing fast, efficient and homogenous processes and reducing side reactions. In view of these benefits, in this study it was purposed to produce bone-like hydroxyapatite (HA) by inducing biomimetic process with microwave-irradiation. This is why, concentrated body fluid (SBF) i.e. 10×SBF-like solution was used and it was precipitated in different microwave powers i.e. 90 W, 360 W, 600 W, and 1200 W and in different exposure times. For comparison, precipitation process was also carried out at room temperature for 6 h and at 80 °C for 1 h. The obtained HA structures were characterized by appropriate instrumental techniques. As a result, microwave-induced precipitation at 600 W for 9 times 30 s was determined as the optimum condition for the production of HA which has similar properties to the cortical bone. At this condition, B-type HA with 9.22% (wt.) carbonate content, 1.61 Ca/P molar ratio and amorphous structure was obtained easily, rapidly and efficiently. So, this is the first time microwave technology has been used to precipitate HA from SBF solution. - Highlights: • Simple, rapid and efficient method was developed to produce bone-like HA. • Microwave radiation and biomimetic approach via 10×SBF-like solution were combined. • Microwave irradiation at 600 W for 9 × 30 s was determined as the optimum condition. • B-type HA (carbonate content: 9.22%; 1.61 Ca/P:1.61; amorph) was produced. • This method may be employed for the effective HA coating of 3D bone scaffolds.

  20. Detection of hydroxyapatite in calcified cardiovascular tissues.

    Science.gov (United States)

    Lee, Jae Sam; Morrisett, Joel D; Tung, Ching-Hsuan

    2012-10-01

    The objective of this study is to develop a method for selective detection of the calcific (hydroxyapatite) component in human aortic smooth muscle cells in vitro and in calcified cardiovascular tissues ex vivo. This method uses a novel optical molecular imaging contrast dye, Cy-HABP-19, to target calcified cells and tissues. A peptide that mimics the binding affinity of osteocalcin was used to label hydroxyapatite in vitro and ex vivo. Morphological changes in vascular smooth muscle cells were evaluated at an early stage of the mineralization process induced by extrinsic stimuli, osteogenic factors and a magnetic suspension cell culture. Hydroxyapatite components were detected in monolayers of these cells in the presence of osteogenic factors and a magnetic suspension environment. Atherosclerotic plaque contains multiple components including lipidic, fibrotic, thrombotic, and calcific materials. Using optical imaging and the Cy-HABP-19 molecular imaging probe, we demonstrated that hydroxyapatite components could be selectively distinguished from various calcium salts in human aortic smooth muscle cells in vitro and in calcified cardiovascular tissues, carotid endarterectomy samples and aortic valves, ex vivo. Hydroxyapatite deposits in cardiovascular tissues were selectively detected in the early stage of the calcification process using our Cy-HABP-19 probe. This new probe makes it possible to study the earliest events associated with vascular hydroxyapatite deposition at the cellular and molecular levels. This target-selective molecular imaging probe approach holds high potential for revealing early pathophysiological changes, leading to progression, regression, or stabilization of cardiovascular diseases. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  1. The Foreign Body Giant Cell Cannot Resorb Bone, But Dissolves Hydroxyapatite Like Osteoclasts.

    Directory of Open Access Journals (Sweden)

    Bas ten Harkel

    Full Text Available Foreign body multinucleated giant cells (FBGCs and osteoclasts share several characteristics, like a common myeloid precursor cell, multinuclearity, expression of tartrate-resistant acid phosphatase (TRAcP and dendritic cell-specific transmembrane protein (DC-STAMP. However, there is an important difference: osteoclasts form and reside in the vicinity of bone, while FBGCs form only under pathological conditions or at the surface of foreign materials, like medical implants. Despite similarities, an important distinction between these cell types is that osteoclasts can resorb bone, but it is unknown whether FBGCs are capable of such an activity. To investigate this, we differentiated FBGCs and osteoclasts in vitro from their common CD14+ monocyte precursor cells, using different sets of cytokines. Both cell types were cultured on bovine bone slices and analyzed for typical osteoclast features, such as bone resorption, presence of actin rings, formation of a ruffled border, and characteristic gene expression over time. Additionally, both cell types were cultured on a biomimetic hydroxyapatite coating to discriminate between bone resorption and mineral dissolution independent of organic matrix proteolysis. Both cell types differentiated into multinucleated cells on bone, but FBGCs were larger and had a higher number of nuclei compared to osteoclasts. FBGCs were not able to resorb bone, yet they were able to dissolve the mineral fraction of bone at the surface. Remarkably, FBGCs also expressed actin rings, podosome belts and sealing zones--cytoskeletal organization that is considered to be osteoclast-specific. However, they did not form a ruffled border. At the gene expression level, FBGCs and osteoclasts expressed similar levels of mRNAs that are associated with the dissolution of mineral (e.g., anion exchange protein 2 (AE2, carbonic anhydrase 2 (CAII, chloride channel 7 (CIC7, and vacuolar-type H+-ATPase (v-ATPase, in contrast the matrix degrading

  2. Plasmonic Properties of Silicon Nanocrystals Doped with Boron and Phosphorus.

    Science.gov (United States)

    Kramer, Nicolaas J; Schramke, Katelyn S; Kortshagen, Uwe R

    2015-08-12

    Degenerately doped silicon nanocrystals are appealing plasmonic materials due to silicon's low cost and low toxicity. While surface plasmonic resonances of boron-doped and phosphorus-doped silicon nanocrystals were recently observed, there currently is poor understanding of the effect of surface conditions on their plasmonic behavior. Here, we demonstrate that phosphorus-doped silicon nanocrystals exhibit a plasmon resonance immediately after their synthesis but may lose their plasmonic response with oxidation. In contrast, boron-doped nanocrystals initially do not exhibit plasmonic response but become plasmonically active through postsynthesis oxidation or annealing. We interpret these results in terms of substitutional doping being the dominant doping mechanism for phosphorus-doped silicon nanocrystals, with oxidation-induced defects trapping free electrons. The behavior of boron-doped silicon nanocrystals is more consistent with a strong contribution of surface doping. Importantly, boron-doped silicon nanocrystals exhibit air-stable plasmonic behavior over periods of more than a year.

  3. Luminescence in colloidal Mn2+-doped semiconductor nanocrystals

    International Nuclear Information System (INIS)

    Beaulac, Remi; Archer, Paul I.; Gamelin, Daniel R.

    2008-01-01

    Recent advances in nanocrystal doping chemistries have substantially broadened the variety of photophysical properties that can be observed in colloidal Mn 2+ -doped semiconductor nanocrystals. A brief overview is provided, focusing on Mn 2+ -doped II-VI semiconductor nanocrystals prepared by direct chemical synthesis and capped with coordinating surface ligands. These Mn 2+ -doped semiconductor nanocrystals are organized into three major groups according to the location of various Mn 2+ -related excited states relative to the energy gap of the host semiconductor nanocrystals. The positioning of these excited states gives rise to three distinct relaxation scenarios following photoexcitation. A brief outlook on future research directions is provided. - Graphical abstract: Mn 2+ -doped semiconductor nanocrystals are organized into three major groups according to the location of various Mn 2+ -related excited states relative to the energy gap of the host semiconductor nanocrystals. The positioning of these excited states gives rise to three distinct relaxation scenarios following photoexcitation

  4. Cloning nanocrystal morphology with soft templates

    Science.gov (United States)

    Thapa, Dev Kumar; Pandey, Anshu

    2016-08-01

    In most template directed preparative methods, while the template decides the nanostructure morphology, the structure of the template itself is a non-general outcome of its peculiar chemistry. Here we demonstrate a template mediated synthesis that overcomes this deficiency. This synthesis involves overgrowth of silica template onto a sacrificial nanocrystal. Such templates are used to copy the morphologies of gold nanorods. After template overgrowth, gold is removed and silver is regrown in the template cavity to produce a single crystal silver nanorod. This technique allows for duplicating existing nanocrystals, while also providing a quantifiable breakdown of the structure - shape interdependence.

  5. Nanostructure of plasma-sprayed hydroxyapatite coating

    International Nuclear Information System (INIS)

    Suvorova, E.I.; Klechkovskaya, V.V.; Bobrovsky, V.V.; Khamchukov, Yu.D.; Klubovich, V.V.

    2003-01-01

    Calcium phosphate coatings were studied by high-resolution transmission microscopy, microdiffraction, and X-ray energy-dispersive spectroscopy. Coatings were prepared by spraying hydroxyapatite targets onto copper, nickel, and chromium substrates and onto NaCl and BaF 2 single crystals in an argon plasma at a gas pressure of ∼1 Pa; the sputter power was about 200 W; and the RF-generator frequency was 13.56 MHz. Under the conditions used, thin layers of nanocrystalline hydroxyapatite were formed regardless of the nature of the substrate

  6. Scaffolds of polycaprolactone with hydroxyapatite fibers

    International Nuclear Information System (INIS)

    Cardoso, Guinea B.C.; Zavaglia, Cecilia A.C.; Arruda, Antonio Celso F.

    2009-01-01

    Scaffolds of poly (ε-caprolactone) has been studied in many researches in tissue engineering. The used of hydroxyapatite fibers, allowed increase its resistance mechanical, beside the character bioactive and osteoconductive. Improving, its role in tissue engineering. The aim in this study was developed polycaprolactone matrix with dispersed hydroxyapatite fibers. The characterizations were by scanning electron microscopy (SEM), X- Ray Diffractometer (XRD), X-Ray Fluorescence (XRF) and Energy dispersive X-Ray Detector (EDX). Was able reviewed its composition, morphology and possible contaminations. The results were scaffolds with porosity and distribution of the fibers in all its area. (author)

  7. An Investigation into the Effects of Interface Stress and Interfacial Arrangement on Temperature Dependent Thermal Properties of a Biological and a Biomimetic Material

    Energy Technology Data Exchange (ETDEWEB)

    Tomar, Vikas [Purdue Univ., West Lafayette, IN (United States)

    2015-01-12

    A significant effort in the biomimetic materials research is on developing materials that can mimic and function in the same way as biological tissues, on bio-inspired electronic circuits, on bio-inspired flight structures, on bio-mimetic materials processing, and on structural biomimetic materials, etc. Most structural biological and biomimetic material properties are affected by two primary factors: (1) interfacial interactions between an organic and an inorganic phase usually in the form of interactions between an inorganic mineral phase and organic protein network; and (2) structural arrangement of the constituents. Examples are exoskeleton structures such as spicule, nacre, and crustacean exoskeletons. A significant effort is being directed towards making synthetic biomimetic materials based on a manipulation of the above two primary factors. The proposed research is based on a hypothesis that in synthetic materials with biomimetic morphology thermal conductivity, k, (how fast heat is carried away) and thermal diffusivity, D, (how fast a material’s temperature rises: proportional to the ratio of k and heat capacity) can be engineered to be either significantly low or significantly high based on a combination of chosen interface orientation and interfacial arrangement in comparison to conventional material microstructures with the same phases and phase volume fractions. METHOD DEVELOPMENT 1. We have established a combined Raman spectroscopy and nanomechanical loading based experimental framework to perform environment (liquid vs. air vs. vacuum) dependent and temperature dependent (~1000 degree-C) in-situ thermal diffusivity measurements in biomaterials at nanoscale to micron scale along with the corresponding analytical theoretic calculations. (Zhang and Tomar, 2013) 2. We have also established a new classical molecular simulation based framework to measure thermal diffusivity in biomolecular interfaces. We are writing a publication currently (Qu and Tomar

  8. Biomimetic modification of synthetic hydrogels by incorporation of adhesive peptides and calcium phosphate nanoparticles: in vitro evaluation of cell behavior

    Directory of Open Access Journals (Sweden)

    M Bongio

    2011-12-01

    Full Text Available The ultimate goal of this work was to develop a biocompatible and biomimetic in situ crosslinkable hydrogel scaffold with an instructive capacity for bone regenerative treatment. To this end, synthetic hydrogels were functionalized with two key components of the extracellular matrix of native bone tissue, i.e. the three-amino acid peptide sequence RGD (which is the principal integrin-binding domain responsible for cell adhesion and survival of anchorage-dependent cells and calcium phosphate (CaP nanoparticles in the form of hydroxyapatite (which are similar to the inorganic phase of bone tissue. Rat bone marrow osteoblast-like cells (OBLCs were encapsulated in four different biomaterials (plain oligo(poly(ethylene glycol fumarate (OPF, RGD-modified OPF, OPF enriched with CaP nanoparticles and RGD-modified OPF enriched with CaP nanoparticles and cell survival, cell spreading, proliferation and mineralized matrix formation were determined via cell viability assay, histology and biochemical analysis for alkaline phosphatase activity and calcium. This study showed that RGD peptide sequences promoted cell spreading in OPF hydrogels and hence play a crucial role in cell survival during the early stage of culture, whereas CaP nanoparticles significantly enhanced cell-mediated hydrogel mineralization. Although cell spreading and proliferation activity were inhibited, the combined effect of RGD peptide sequences and CaP nanoparticles within OPF hydrogel systems elicited a better biological response than that of the individual components. Specifically, both a sustained cell viability and mineralized matrix production mediated by encapsulated OBLCs were observed within these novel biomimetic composite systems.

  9. Electric field-assisted formation of organically modified hydroxyapatite (ormoHAP) spheres in carboxymethylated gelatin gels.

    Science.gov (United States)

    Heinemann, C; Heinemann, S; Kruppke, B; Worch, H; Thomas, J; Wiesmann, H P; Hanke, T

    2016-10-15

    A biomimetic strategy was developed in order to prepare organically modified hydroxyapatite (ormoHAP) with spherical shape. The technical approach is based on electric field-assisted migration of calcium ions and phosphate ions into a hydrogel composed of carboxymethylated gelatin. The electric field as well as the carboxymethylation using glucuronic acid (GlcA) significantly accelerates the mineralization process, which makes the process feasible for lab scale production of ormoHAP spheres and probably beyond. A further process was developed for gentle separation of the ormoHAP spheres from the gelatin gel without compromising the morphology of the mineral. The term ormoHAP was chosen since morphological analyses using electron microscopy (SEM, TEM) and element analysis (EDX, FT-IR, XRD) confirmed that carboxymethylated gelatin molecules use to act as organic templates for the formation of nanocrystalline HAP. The hydroxyapatite (HAP) crystals self-organize to form hollow spheres with diameters ranging from 100 to 500nm. The combination of the biocompatible chemical composition and the unique structure of the nanocomposites is considered to be a useful basis for future applications in functionalized degradable biomaterials. A novel bioinspired mineralization process was developed based on electric field-assisted migration of calcium and phosphate ions into biochemically carboxymethylated gelatin acting as organic template. Advantages over conventional hydroxyapatite include particle size distribution and homogeneity as well as achievable mechanical properties of relevant composites. Moreover, specifically developed calcium ion or phosphate ion release during degradation can be useful to adjust the fate of bone cells in order to manipulate remodeling processes. The hollow structure of the spheres can be useful for embedding drugs in the core, encapsulated by the highly mineralized outer shell. In this way, controlled drug release could be achieved, which enables

  10. Prospects of Colloidal Copper Chalcogenide Nanocrystals

    NARCIS (Netherlands)

    van der Stam, W.; Berends, A.C.; de Mello-Donega, Celso

    2016-01-01

    Over the past few years, colloidal copper chalcogenide nanocrystals (NCs) have emerged as promising alternatives to conventional Cd and Pb chalcogenide NCs. Owing to their wide size, shape, and composition tunability, Cu chalcogenide NCs hold great promise for several applications, such as

  11. Hafnium carbide nanocrystal chains for field emitters

    International Nuclear Information System (INIS)

    Tian, Song; Li, Hejun; Zhang, Yulei; Ren, Jincui; Qiang, Xinfa; Zhang, Shouyang

    2014-01-01

    A hafnium carbide (HfC) nanostructure, i.e., HfC nanocrystal chain, was synthesized by a chemical vapor deposition (CVD) method. X-ray diffractometer, field-emission scanning electron microscope, transmission electron microscope, and energy-dispersive X-ray spectrometer were employed to characterize the product. The synthesized one-dimensional (1D) nanostructures with many faceted octahedral nanocrystals possess diameters of tens of nanometers to 500 nm and lengths of a few microns. The chain-like structures possess a single crystalline structure and preferential growth direction along the [1 0 0] crystal orientation. The growth of the chains occurred through the vapor–liquid–solid process along with a negative-feedback mechanism. The field emission (FE) properties of the HfC nanocrystal chains as the cold cathode emitters were examined. The HfC nanocrystal chains display good FE properties with a low turn-on field of about 3.9 V μm −1 and a high field enhancement factor of 2157, implying potential applications in vacuum microelectronics.

  12. Atomic force microscopy characterization of cellulose nanocrystals

    Science.gov (United States)

    Roya R. Lahiji; Xin Xu; Ronald Reifenberger; Arvind Raman; Alan Rudie; Robert J. Moon

    2010-01-01

    Cellulose nanocrystals (CNCs) are gaining interest as a “green” nanomaterial with superior mechanical and chemical properties for high-performance nanocomposite materials; however, there is a lack of accurate material property characterization of individual CNCs. Here, a detailed study of the topography, elastic and adhesive properties of individual wood-derived CNCs...

  13. Biocompatibility of bio based calcium carbonate nanocrystals ...

    African Journals Online (AJOL)

    Background: Currently, there has been extensive research interest for inorganic nanocrystals such as calcium phosphate, iron oxide, silicone, carbon nanotube and layered double hydroxide as a drug delivery system especially in cancer therapy. However, toxicological screening of such particles is paramount importance ...

  14. Solvothermal synthesis and characterization of CZTS nanocrystals

    Science.gov (United States)

    Dumasiya, Ajay; Shah, N. M.

    2017-05-01

    Cu2ZnSnS4 (CZTS) is a promising thin film absorber material for low cost solar cell applications. CZTS nanoparticle ink synthesized using solvothermal route is an attractive option to deposit absorber layer using screen printing or spin coating method in CZTS thin film solar cell. In this study we have synthesized CZTS nanocrystals using solvothermal method from aqueous solution of Copper nitrate [Cu(NO3)2], Zinc nitrate [Zn(NO3)2], tin chloride [SnCl4] and thiourea with varying concentration of Cu(NO3)2 (viz 0.82 mmol,1.4 mmol, 1.7 mmol) keeping concentrations of rest of solutions constant. As synthesized CZTS nanocrystals are characterized using Energy Dispersive Analysis of X-rays (EDAX) to verify stoichiometry of elements. Analysis of EDAX data suggests that CZTS nanocrystals having Copper nitrate [Cu (NO3)2] concentration of 1.4 m mole is near stoichiometric. X-ray diffraction analysis study of CZTS nanocrystals having Copper nitrate [Cu (NO3)2] concentration of 1.4 m mole reveals the preferred orientation of the grains in (112), (220) and (312) direction confirming Kesterite structure of CZTS.

  15. Thick-shell nanocrystal quantum dots

    Science.gov (United States)

    Hollingsworth, Jennifer A [Los Alamos, NM; Chen, Yongfen [Eugene, OR; Klimov, Victor I [Los Alamos, NM; Htoon, Han [Los Alamos, NM; Vela, Javier [Los Alamos, NM

    2011-05-03

    Colloidal nanocrystal quantum dots comprising an inner core having an average diameter of at least 1.5 nm and an outer shell, where said outer shell comprises multiple monolayers, wherein at least 30% of the quantum dots have an on-time fraction of 0.80 or greater under continuous excitation conditions for a period of time of at least 10 minutes.

  16. Biodegradation behaviors of cellulose nanocrystals -PVA nanocomposites

    Directory of Open Access Journals (Sweden)

    Mahdi Rohani

    2014-11-01

    Full Text Available In this research, biodegradation behaviors of cellulose nanocrystals-poly vinyl alcohol nanocomposites were investigated. Nanocomposite films with different filler loading levels (3, 6, 9 and 12% by wt were developed by solvent casting method. The effect of cellulose nanocrystals on the biodegradation behaviors of nanocomposite films was studied. Water absorption and water solubility tests were performed by immersing specimens into distilled water. The characteristic parameter of diffusion coefficient and maximum moisture content were determined from the obtained water absorption curves. The water absorption behavior of the nanocomposites was found to follow a Fickian behavior. The maximum water absorption and diffusion coefficients were decreased by increasing the cellulose nanocrystals contents, however the water solubility decrease. The biodegradability of the films was investigated by immersing specimens into cellulase enzymatic solution as well as by burial in soil. The results showed that adding cellulose nanocrystals increase the weight loss of specimens in enzymatic solution but decrease it in soil media. The limited biodegradability of specimens in soil media attributed to development of strong interactions with solid substrates that inhibit the accessibility of functional groups. Specimens with the low degree of hydrolysis underwent extensive biodegradation in both enzymatic and soil media, whilst specimens with the high degree of hydrolysis showed recalcitrance to biodegradation under those conditions.

  17. Mechanistic Study of Monodisperse Iron Oxide Nanocrystals ...

    African Journals Online (AJOL)

    To gain better insight into the formation of iron oxide nanocrystals from the solution phase thermal decomposition of iron (III) oleate complex, different reaction conditions including time, heating ramp, as well as concentrations of iron oleate precursor and oleic acid ligand were systematically varied and the resulting ...

  18. Silicon nanocrystal films for electronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Lechner, Robert W.

    2009-02-06

    Whether nanoparticles of silicon are really suited for such applications, whether layers fabricated from this exhibit semiconducting properties, whether they can be doped, and whether for instance via the doping the conductivity can be tuned, was studied in the present thesis. Starting material for this were on the one hand spherical silicon nanocrystals with a sharp size distribution and mean diameters in the range from 4-50 nm. Furthermore silicon particle were available, which are with 50-500 nm distinctly larger and exhibit a broad distribution of the mean size and a polycrystalline fine structure with strongly bifurcated external morphology. The small conductivities and tje low mobility values of the charge carriers in the layers of silicon nanocrystals suggest to apply suited thermal after-treatment procedures. So was found that the aluminium-induced layer exchange (ALILE) also can be transferred to the porous layers of nanocrystals. With the deuteron passivation a method was available to change the charge-carrier concentration in the polycrystalline layers. Additionally to ALILE laser crystallization as alternative after-treatment procedure of the nanocrystal layers was studied.

  19. Microstructures, hardness and bioactivity of hydroxyapatite coatings

    CSIR Research Space (South Africa)

    Tlotleng, Monnamme

    2014-10-01

    Full Text Available Hydroxyapatite (HAP) coatings on bioinert metals such as Ti–6Al–4V are necessary for biomedical applications. Together, HAP and Ti–6Al–4V are biocompatible and bioactive. The challenges of depositing HAP on Ti–6Al–4V with traditional thermal...

  20. Continuous microwave flow synthesis of mesoporous hydroxyapatite.

    Science.gov (United States)

    Akram, Muhammad; Alshemary, Ammar Z; Goh, Yi-Fan; Wan Ibrahim, Wan Aini; Lintang, Hendrik O; Hussain, Rafaqat

    2015-11-01

    We have successfully used continuous microwave flow synthesis (CMFS) technique for the template free synthesis of mesoporous hydroxyapatite. The continuous microwave flow reactor consisted of a modified 2.45GHz household microwave, peristaltic pumps and a Teflon coil. This cost effective and efficient system was exploited to produce semi-crystalline phase pure nano-sized hydroxyapatite. Effect of microwave power, retention time and the concentration of reactants on the phase purity, degree of crystallinity and surface area of the final product was studied in detail. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to study the phase purity and composition of the product, while transmission electron microscopy (TEM) was used to study the effect of process parameters on the morphology of hydroxyapatite. The TEM analysis confirmed the formation of spherical particles at low microwave power; however the morphology of the particles changed to mesoporous needle and rod-like structure upon exposing the reaction mixture to higher microwave power and longer retention time inside the microwave. The in-vitro ion dissolution behavior of the as synthesized hydroxyapatite was studied by determining the amount of Ca(2+) ion released in SBF solution. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Pulsed laser deposition of hydroxyapatite thin films

    Czech Academy of Sciences Publication Activity Database

    Koch, C.F.; Johnson, S.; Kumar, D.; Jelínek, Miroslav; Chrisey, D.B.; Doraiswamy, A.; Jin, C.; Narayan, R.J.; Mihailescu, I. N.

    2007-01-01

    Roč. 27, - (2007), s. 484-494 ISSN 0928-4931 Institutional research plan: CEZ:AV0Z10100522 Keywords : hydroxyapatite * pulsed laser deposition * bioactive ceramic s Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.486, year: 2007

  2. Microwave assisted synthesis of hydroxyapatite nano strips

    Energy Technology Data Exchange (ETDEWEB)

    Ruban Kumar, A.; Kalainathan, S.; Saral, A.M. [School of Advanced Sciences, VIT University, Vellore 632014, Tamil Nadu (India)

    2010-07-15

    Synthesis of hydroxyapatite (HAP) nano strips was carried out by chemical precipitation method followed by microwave irradiation. The microwave assisted reactions proceed at fast rates. It is found that the presence of the complex reagent EDTA plays an important role in the morphological changes of nanostructure hydroxyapatite. EDTA acts as a hexadentate unit by wrapping itself around the Ca{sup 2+} metal ion with, four oxygen and two nitrogen atoms and forms several five member chelate rings. The relative specific surface energies associated with the facets of the crystal determines the shape of the crystal. Scanning electron microscopy revealed the presence of hydroxyapatite nano strips with the range 50-100 nm in EDTA influenced HAP powders. Fourier transform-infrared spectroscopy (FT-IR) result combined with the X-ray diffraction (XRD) indicates the presence of amorphous hydroxyapatite (HAP) in the as-prepared material. X-ray patterns collected on the powder after heat-treatment at 1100 C for 2 h in air exhibits single phase of HAP. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Biomimetics: forecasting the future of science, engineering, and medicine

    Directory of Open Access Journals (Sweden)

    Hwang J

    2015-09-01

    Full Text Available Jangsun Hwang,1 Yoon Jeong,1,2 Jeong Min Park,3 Kwan Hong Lee,1,2,4 Jong Wook Hong,1,2 Jonghoon Choi1,2 1Department of Bionano Technology, Graduate School, Hanyang University, Seoul, 2Department of Bionano Engineering, Hanyang University ERICA, Ansan, Korea; 3Department of Biomedical Engineering, Boston University, 4OpenView Venture Partners, Boston, MA, USA Abstract: Biomimetics is the study of nature and natural phenomena to understand the principles of underlying mechanisms, to obtain ideas from nature, and to apply concepts that may benefit science, engineering, and medicine. Examples of biomimetic studies include fluid-drag reduction swimsuits inspired by the structure of shark’s skin, velcro fasteners modeled on burrs, shape of airplanes developed from the look of birds, and stable building structures copied from the backbone of turban shells. In this article, we focus on the current research topics in biomimetics and discuss the potential of biomimetics in science, engineering, and medicine. Our report proposes to become a blueprint for accomplishments that can stem from biomimetics in the next 5 years as well as providing insight into their unseen limitations. Keywords: biomimicry, tissue engineering, biomaterials, nature, nanotechnology, nanomedicine

  4. Biomimetic chemical sensors using bioengineered olfactory and taste cells.

    Science.gov (United States)

    Du, Liping; Zou, Ling; Zhao, Luhang; Wang, Ping; Wu, Chunsheng

    2014-01-01

    Biological olfactory and taste systems are natural chemical sensing systems with unique performances for the detection of environmental chemical signals. With the advances in olfactory and taste transduction mechanisms, biomimetic chemical sensors have achieved significant progress due to their promising prospects and potential applications. Biomimetic chemical sensors exploit the unique capability of biological functional components for chemical sensing, which are often sourced from sensing units of biological olfactory or taste systems at the tissue level, cellular level, or molecular level. Specifically, at the cellular level, there are mainly two categories of cells have been employed for the development of biomimetic chemical sensors, which are natural cells and bioengineered cells, respectively. Natural cells are directly isolated from biological olfactory and taste systems, which are convenient to achieve. However, natural cells often suffer from the undefined sensing properties and limited amount of identical cells. On the other hand, bioengineered cells have shown decisive advantages to be applied in the development of biomimetic chemical sensors due to the powerful biotechnology for the reconstruction of the cell sensing properties. Here, we briefly summarized the most recent advances of biomimetic chemical sensors using bioengineered olfactory and taste cells. The development challenges and future trends are discussed as well.

  5. Sustainability assessment of a lightweight biomimetic ceiling structure

    International Nuclear Information System (INIS)

    Antony, Florian; Speck, Thomas; Speck, Olga; Grießhammer, Rainer

    2014-01-01

    An intensive and continuous debate centres on the question of whether biomimetics has a specific potential to contribute to sustainability. In the context of a case study, the objective of this paper is to contribute to this debate by presenting the first systematic approach to assess the sustainability of a complex biomimetic product. The object of inquiry is a lecture hall's ribbed slab. Based on criteria suggested by the Association of German Engineers (VDI), it has been verified that the slab has been correctly defined as biomimetic. Moreover, a systematic comparative product sustainability assessment has been carefully carried out. For purposes of comparison, estimated static calculations have been performed for conceivable current state-of-the-art lightweight ceiling structures. Alternative options are a hollow article slab and a pre-stressed flat slab. Besides a detailed benefit analysis and a discussion of social effects, their costs have also been compared. A particularly detailed life cycle assessment on the respective environmental impacts has also been performed. Results show that the biomimetic ribbed slab built in the 1960s is able to keep up with the current state-of-the-art lightweight solutions in terms of sustainability. These promising results encourage a systematic search for a broad range of sustainable biomimetic solutions. (paper)

  6. Reverse Engineering Nature to Design Biomimetic Total Knee Implants.

    Science.gov (United States)

    Varadarajan, Kartik Mangudi; Zumbrunn, Thomas; Rubash, Harry E; Malchau, Henrik; Muratoglu, Orhun K; Li, Guoan

    2015-10-01

    While contemporary total knee arthroplasty (TKA) provides tremendous clinical benefits, the normal feel and function of the knee is not fully restored. To address this, a novel design process was developed to reverse engineer "biomimetic" articular surfaces that are compatible with normal soft-tissue envelope and kinematics of the knee. The biomimetic articular surface is created by moving the TKA femoral component along in vivo kinematics of normal knees and carving out the tibial articular surface from a rectangular tibial block. Here, we describe the biomimetic design process. In addition, we utilize geometric comparisons and kinematic simulations to show that; (1) tibial articular surfaces of conventional implants are fundamentally incompatible with normal knee motion, and (2) the anatomic geometry of the biomimetic surface contributes directly to restoration of normal knee kinematics. Such biomimetic implants may enable us to achieve the long sought after goal of a "normal" knee post-TKA surgery. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  7. Tubular inverse opal scaffolds for biomimetic vessels

    Science.gov (United States)

    Zhao, Ze; Wang, Jie; Lu, Jie; Yu, Yunru; Fu, Fanfan; Wang, Huan; Liu, Yuxiao; Zhao, Yuanjin; Gu, Zhongze

    2016-07-01

    There is a clinical need for tissue-engineered blood vessels that can be used to replace or bypass damaged arteries. The success of such grafts depends strongly on their ability to mimic native arteries; however, currently available artificial vessels are restricted by their complex processing, controversial integrity, or uncontrollable cell location and orientation. Here, we present new tubular scaffolds with specific surface microstructures for structural vessel mimicry. The tubular scaffolds are fabricated by rotationally expanding three-dimensional tubular inverse opals that are replicated from colloidal crystal templates in capillaries. Because of the ordered porous structure of the inverse opals, the expanded tubular scaffolds are imparted with circumferentially oriented elliptical pattern microstructures on their surfaces. It is demonstrated that these tailored tubular scaffolds can effectively make endothelial cells to form an integrated hollow tubular structure on their inner surface and induce smooth muscle cells to form a circumferential orientation on their outer surface. These features of our tubular scaffolds make them highly promising for the construction of biomimetic blood vessels.There is a clinical need for tissue-engineered blood vessels that can be used to replace or bypass damaged arteries. The success of such grafts depends strongly on their ability to mimic native arteries; however, currently available artificial vessels are restricted by their complex processing, controversial integrity, or uncontrollable cell location and orientation. Here, we present new tubular scaffolds with specific surface microstructures for structural vessel mimicry. The tubular scaffolds are fabricated by rotationally expanding three-dimensional tubular inverse opals that are replicated from colloidal crystal templates in capillaries. Because of the ordered porous structure of the inverse opals, the expanded tubular scaffolds are imparted with circumferentially

  8. Biomimetic electrochemistry from conducting polymers. A review

    International Nuclear Information System (INIS)

    Otero, T.F.; Martinez, J.G.; Arias-Pardilla, J.

    2012-01-01

    Highlights: ► Composition and properties of conducting polymers change during reactions. ► These properties are being exploited to develop biomimetic reactive and soft devices. ► The state of the art for artificial muscles sensing working conditions was reviewed. ► Smart membranes, drug delivery devices and nervous interfaces were also reviewed. - Abstract: Films of conducting polymers in the presence of electrolytes can be oxidized or reduced by the flow of anodic or cathodic currents. Ions and solvent are exchanged during a reaction for charge and osmotic pressure balance. A reactive conducting polymer contains ions and solvent. Such variation of composition during a reaction is reminiscent of the biological processes in cells. Along changes to the composition of the material during a reaction, there are also changes to other properties, including: volume (electrochemomechanical), colour (electrochromic), stored charge (electrical storage), porosity or permselectivity (electroporosity), stored chemicals, wettability and so on. Most of those properties mimic similar property changes in organs during their functioning. These properties are being exploited to develop biomimetic reactive and soft devices: artificial muscles and polymeric actuators; supercapacitors and all organic batteries; smart membranes; electron-ion transducers; nervous interfaces and artificial synapses, or drug delivery devices. In this review we focus on the state of the art for artificial muscles, smart membranes and electron-ion transducers. The reactive nature of those devices provide them with a unique advantage related to the present days technologies: any changes in the surrounding physical or chemical variable acting on the electrochemical reaction rate will be sensed by the device while working. Working under constant current (driving signal), the evolution of the device potential or the evolution of the consumed electrical energy (sensing signals) senses and quantifies the

  9. Chemical treatment and biomimetic coating evaluating in zirconia-alumina ceramics

    International Nuclear Information System (INIS)

    Aguiar, Amanda Abati

    2007-01-01

    Ceramic materials, as alumina and zirconia have been explored along the years as biomaterials application. The bio inert nature has been stimulating the development of new alternatives, as chemical treatments to improve the biological application of these ceramics. The biomimetic process of bio inert ceramics for coating apatite is based on soaking the implant in a simulated body fluid, SBF, with ion concentrations nearly equal to those of human blood plasma. The bioactivity of the material is related with the formation of a layer constituted of hydroxyapatite low crystalline, similar to the biological apatite. The biocompatibility associated to the structural properties of the alumina and zirconia has been stimulating the clinical use of these materials, mainly in areas of larger mechanical requests, places not recommended for bioactive hydroxyapatite, for instance. In this work samples of alumina, zirconia doped with Yttria (3% mol) and composites of alumina and zirconia doped with Yttria (3% mol) were prepared by co-precipitation method, calcinate, sintered, chemically treated with solutions of acid phosphoric and sodium hydroxide and them immersed in 1.0 M and 1.5 M SBF. The calcinate powders were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), gas adsorption (BET) and laser diffraction. The XRD results indicate that the samples are low crystalline. It was observed for BET that the samples present high specific surface area. The results of laser diffraction and SEM showed that the powders are agglomerates. The sintered samples were analyzed by XRD, SEM and X-ray fluorescence (XRF). The phases quantified by Rietveld method were: cubic, tetragonal and monoclinic of the zirconia, besides the phase alpha of the alumina. The chemical treatment with phosphoric acid didn't present a tendency of larger apatite formation in relation to the samples no chemically treated. The treatment with sodium hydroxide provoked accentuated transformation of

  10. Adsorption of nickel on synthetic hydroxyapatite from aqueous solutions

    International Nuclear Information System (INIS)

    Rosskopfova, O.; Galambos, M.; Pivarciova, L.; Rajec, P.; Caplovicova, M.

    2013-01-01

    The sorption of nickel on synthetic hydroxyapatite was investigated using a batch method and radiotracer technique. The hydroxyapatite samples used in experiments were a commercial hydroxyapatite and hydroxyapatite of high crystallinity with Ca/P ratio of 1.563 and 1.688, respectively, prepared by a wet precipitation process. The sorption of nickel on hydroxyapatite was pH independent ranging from 4.5 to 6.5 as a result of buffering properties of hydroxyapatite. The adsorption of nickel was rapid and the percentage of Ni sorption on both samples of hydroxyapatite was >98 % during the first 15-30 min of the contact time for initial Ni 2+ concentration of 1 x 10 -4 mol dm -3 . The experimental data for sorption of nickel have been interpreted in the term of Langmuir isotherm and the value of maximum sorption capacity of nickel on a commercial hydroxyapatite and hydroxyapatite prepared by wet precipitation process was calculated to be 0.184 and 0.247 mmol g -1 , respectively. The sorption of Ni 2+ ions was performed by ion-exchange with Ca 2+ cations on the crystal surface of hydroxyapatite under experimental conditions. The competition effect of Co 2+ and Fe 2+ towards Ni 2+ sorption was stronger than that of Ca 2+ ions. NH 4 + ions have no apparent effect on nickel sorption. (author)

  11. Valorization of Bone Waste of Saudi Arabia by Synthesizing Hydroxyapatite.

    Science.gov (United States)

    Amna, Touseef

    2018-05-09

    At present, hydroxyapatite is being frequently used for diverse biomedical applications as it possesses excellent biocompatibility, osteoconductivity, and non-immunogenic characteristics. The aim of the present work was to recycle bone waste for synthesis of hydroxyapatite nanoparticles to be used as bone extracellular matrix. For this reason, we for the first time utilized bio-waste of cow bones of Albaha city. The residual bones were utilized for the extraction of natural bone precursor hydroxyapatite. A facile scientific technique has been used to synthesize hydroxyapatite nanoparticles through calcinations of wasted cow bones without further supplementation of chemicals/compounds. The obtained hydroxyapatite powder was ascertained using physicochemical techniques such as XRD, SEM, FTIR, and EDX. These analyses clearly show that hydroxyapatite from native cow bone wastes is biologically and physicochemically comparable to standard hydroxyapatite, commonly used for biomedical functions. The cell viability and proliferation over the prepared hydroxyapatite was confirmed with CCk-8 colorimetric assay. The morphology of the cells growing over the nano-hydroxyapatite shows that natural hydroxyapatite promotes cellular attachment and proliferation. Hence, the as-prepared nano-hydroxyapatite can be considered as cost-effective source of bone precursor hydroxyapatite for bone tissue engineering. Taking into account the projected demand for reliable bone implants, the present research work suggested using environment friendly methods to convert waste of Albaha city into nano-hydroxyapatite scaffolds. Therefore, besides being an initial step towards accomplishment of projected demands of bone implants in Saudi Arabia, our study will also help in reducing the environmental burden by recycling of bone wastes of Albaha city.

  12. Synthesis of nanocrystals and nanocrystal self-assembly

    Science.gov (United States)

    Chen, Zhuoying

    Chapter 1. A general introduction is presented on nanomaterials and nanoscience. Nanoparticles are discussed with respect to their structure and properties. Ferroelectric materials and nanoparticles in particular are highlighted, especially in the case of the barium titanate, and their potential applications are discussed. Different nanocrystal synthetic techniques are discussed. Nanoparticle superlattices, the novel "meta-materials" built from self-assembly at the nanoscale, are introduced. The formation of nanoparticle superlattices and the importance and interest of synthesizing these nanostructures is discussed. Chapter 2. Advanced applications for high k dielectric and ferroelectric materials in the electronics industry continues to demand an understanding of the underlying physics in decreasing dimensions into the nanoscale. The first part of this chapter presents the synthesis, processing, and electrical characterization of nanostructured thin films (thickness ˜100 nm) of barium titanate BaTiO3 built from uniform nanoparticles (alcohols were used to study the effect of size and morphological control over the nanocrystals. Techniques including X-ray diffraction, transmission electron microscopy, selected area electron diffraction, and high-resolution electron microscopy are used to examine crystallinity and morphology. Chapter 3. By investigating the self-assembly of cadmium selenide-gold (CdSe-Au) nanoparticle mixtures by transmission electron microscopy after solvent evaporation, the effect of solvents in the formation process of CdSe-Au binary nanoparticle superlattices (BNSLs) was studied. 1-dodecanethiol was found to be critical in generating conditions necessary for superlattice formation, prior to the other factors that likely determine structure, highlighting the dual role of this organic polar molecule as both ligand and high boiling point/crystallization solvent. The influence of thiol was investigated under various concentrations (and also

  13. A Parallel Modular Biomimetic Cilia Sorting Platform

    Directory of Open Access Journals (Sweden)

    James G. H. Whiting

    2018-03-01

    Full Text Available The aquatic unicellular organism Paramecium caudatum uses cilia to swim around its environment and to graze on food particles and bacteria. Paramecia use waves of ciliary beating for locomotion, intake of food particles and sensing. There is some evidence that Paramecia pre-sort food particles by discarding larger particles, but intake the particles matching their mouth cavity. Most prior attempts to mimic cilia-based manipulation merely mimicked the overall action rather than the beating of cilia. The majority of massive-parallel actuators are controlled by a central computer; however, a distributed control would be far more true-to-life. We propose and test a distributed parallel cilia platform where each actuating unit is autonomous, yet exchanging information with its closest neighboring units. The units are arranged in a hexagonal array. Each unit is a tileable circuit board, with a microprocessor, color-based object sensor and servo-actuated biomimetic cilia actuator. Localized synchronous communication between cilia allowed for the emergence of coordinated action, moving different colored objects together. The coordinated beating action was capable of moving objects up to 4 cm/s at its highest beating frequency; however, objects were moved at a speed proportional to the beat frequency. Using the local communication, we were able to detect the shape of objects and rotating an object using edge detection was performed; however, lateral manipulation using shape information was unsuccessful.

  14. Scaling laws for a compliant biomimetic swimmer

    Science.gov (United States)

    Gibouin, Florence; Raufaste, Christophe; Bouret, Yann; Argentina, Mederic

    2017-11-01

    Motivated by the seminal work of Lord Lighthill in the sixties, we study the motion of inertial aquatic swimmers that propels with undulatory gaits. In 2014, Gazzola et al. have uncovered the law linking the swimming velocity to the kinematics of the swimmer and the fluid properties. At high Reynolds numbers, the velocity appears to be equal to 0.4 Af /(2 π) , where A and f are respectively the amplitude and the frequency of the oscillating fin. We have constructed a compliant biomimetic swimmer, whose muscles have been modeled through a torque distribution thanks to a servomotor. A soft polymeric material mimics the flesh and provides the flexibility. By immersing our robot into a water tunnel, we find and characterize the operating point for which the propulsive force balances the drag. We bring the first experimental proof of the former law and probe large amplitude undulations which exhibits nonlinear effects. All data collapse perfectly onto a single master curve. We investigate the role of the fin flexibility by varying its length and its thickness and we figured out the existence of an efficient swimming regime. We thank the support of CNRS and Université Côte d'Azur.

  15. Biomimetic soluble collagen purified from bones.

    Science.gov (United States)

    Ferreira, Ana Marina; Gentile, Piergiorgio; Sartori, Susanna; Pagliano, Cristina; Cabrele, Chiara; Chiono, Valeria; Ciardelli, Gianluca

    2012-11-01

    Type I collagen has been extensively exploited as a biomaterial for biomedical applications and drug delivery; however, small molecular alterations occurring during the isolation procedure and its interaction with residual bone extracellular matrix molecules or proteins might affect the overall material biocompatibility and performance. The aim of the current work is to study the potential alterations in collagen properties and organization associated with the absence of proteoglycans, which mimic pathological conditions associated with age-related diseases. A new approach for evaluating the effect of proteoglycans on the properties of isolated type I collagen from the bone matrix is described. Additional treatment with guanidine hydrochloride was introduced to remove residual proteoglycans from the collagen matrix. The properties of the isolated collagen with/without guanidine hydrochloride treatment were investigated and compared with a commercial rabbit collagen as control. We demonstrate that the absence of proteoglycans in the isolated type I collagen affects its thermal properties, the extraction into its native structure, and its ability to hydrate and self-assemble into fibers. The fine control and tuning of all these features, linked to the absence of non-collagenous proteins as proteoglycans, offer the possibility of designing new strategies and biomaterials with advanced biomimetic properties aimed at regenerating bone tissue in the case of fragility and/or defects. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Directed Fluid Transport with Biomimetic ``Silia'' Arrays

    Science.gov (United States)

    Shields, A. R.; Evans, B. A.; Carstens, B. L.; Falvo, M. R.; Washburn, S.; Superfine, R.

    2008-10-01

    We present results on the long-range, directed fluid transport produced by the collective beating of arrays of biomimetic ``silia.'' Silia are arrays of free-standing nanorods roughly the size of biological cilia, which we fabricate from a polymer-magnetic nanoparticle composite material. With external permanent magnets we actuate our silia such that their motion mimics the beating of biological cilia. Biological cilia have evolved to produce microscale fluid transport and are increasingly being recognized as critical components in a wide range of biological systems. However, despite much effort cilia generated fluid flows remain an area of active study. In the last decade, cilia-driven fluid flow in the embryonic node of vertebrates has been implicated as the initial left-right symmetry breaking event in these embryos. With silia we generate directional fluid transport by mimicking the tilted conical beating of these nodal cilia and seek to answer open questions about the nature of particle advection in such a system. By seeding fluorescent microparticles into the fluid we have noted the existence of two distinct flow regimes. The fluid flow is directional and coherent above the tips of the silia, while between the silia tips and floor particle motion is complicated and suggestive of chaotic advection.

  17. Biomimetic micromechanical adaptive flow-sensor arrays

    Science.gov (United States)

    Krijnen, Gijs; Floris, Arjan; Dijkstra, Marcel; Lammerink, Theo; Wiegerink, Remco

    2007-05-01

    We report current developments in biomimetic flow-sensors based on flow sensitive mechano-sensors of crickets. Crickets have one form of acoustic sensing evolved in the form of mechanoreceptive sensory hairs. These filiform hairs are highly perceptive to low-frequency sound with energy sensitivities close to thermal threshold. In this work we describe hair-sensors fabricated by a combination of sacrificial poly-silicon technology, to form silicon-nitride suspended membranes, and SU8 polymer processing for fabrication of hairs with diameters of about 50 μm and up to 1 mm length. The membranes have thin chromium electrodes on top forming variable capacitors with the substrate that allow for capacitive read-out. Previously these sensors have been shown to exhibit acoustic sensitivity. Like for the crickets, the MEMS hair-sensors are positioned on elongated structures, resembling the cercus of crickets. In this work we present optical measurements on acoustically and electrostatically excited hair-sensors. We present adaptive control of flow-sensitivity and resonance frequency by electrostatic spring stiffness softening. Experimental data and simple analytical models derived from transduction theory are shown to exhibit good correspondence, both confirming theory and the applicability of the presented approach towards adaptation.

  18. Hydrogen Tunneling in Enzymes and Biomimetic Models

    Energy Technology Data Exchange (ETDEWEB)

    Layfield, Joshua P.; Hammes-Schiffer, Sharon

    2014-04-09

    Hydrogen transfer reactions play an important role throughout chemistry and biology. In general, hydrogen transfer reactions encompass proton and hydride transfer, which are associated with the transfer of a positively or negatively charged species, respectively, and proton-coupled electron transfer (PCET), which corresponds to the net transfer of one electron and one proton in the simplest case. Such PCET reactions can occur by either a sequential mechanism, in which the proton or electron transfers first, or a concerted mechanism, in which the electron and proton transfer in a single kinetic step with no stable intermediate. Furthermore, concerted PCET reactions can be subdivided into hydrogen atom transfer (HAT), which corresponds to the transfer of an electron and proton between the same donor and acceptor (i.e., the transfer of a predominantly neutral species), and electron-proton transfer (EPT), which corresponds to the transfer of an electron and proton between different donors and acceptors, possibly even in different directions. In all of these types of hydrogen transfer reactions, hydrogen tunneling could potentially play a significant role. The biomimetic portion was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences.

  19. Hydrogen Tunneling in Enzymes and Biomimetic Models

    Energy Technology Data Exchange (ETDEWEB)

    Layfield, Joshua P.; Hammes-Schiffer, Sharon

    2013-12-20

    Hydrogen transfer reactions play an important role throughout chemistry and biology. In general, hydrogen transfer reactions encompass proton and hydride transfer, which are associated with the transfer of a positively or negatively charged species, respectively, and proton-coupled electron transfer (PCET), which corresponds to the net transfer of one electron and one proton in the simplest case. Such PCET reactions can occur by either a sequential mechanism, in which the proton or electron transfers first, or a concerted mechanism, in which the electron and proton transfer in a single kinetic step with no stable intermediate. Furthermore, concerted PCET reactions can be subdivided into hydrogen atom transfer (HAT), which corresponds to the transfer of an electron and proton between the same donor and acceptor (i.e., the transfer of a predominantly neutral species), and electron-proton transfer (EPT), which corresponds to the transfer of an electron and proton between different donors and acceptors, possibly even in different directions. In all of these types of hydrogen transfer reactions, hydrogen tunneling could potentially play a signficant role. The theoretical development portion of this Review was supported by the National Science Foundation under CHE-10-57875. The biological portion of this Review was funded by NIH Grant No. GM056207. The biomimetic portion was supported as part of the Center for Molecular Electro-catalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences.

  20. Desalination by biomimetic aquaporin membranes: Review of status and prospects

    DEFF Research Database (Denmark)

    Tang, C.Y.; Zhao, Y.; Wang, R.

    2013-01-01

    Based on their unique combination of offering high water permeability and high solute rejection aquaporin proteins have attracted considerable interest over the last years as functional building blocks of biomimetic membranes for water desalination and reuse. The purpose of this review is to prov......Based on their unique combination of offering high water permeability and high solute rejection aquaporin proteins have attracted considerable interest over the last years as functional building blocks of biomimetic membranes for water desalination and reuse. The purpose of this review...... is to provide an overview of the properties of aquaporins, their preparation and characterization. We discuss the challenges in exploiting the remarkable properties of aquaporin proteins for membrane separation processes and we present various attempts to construct aquaporin in membranes for desalination......; including an overview of our own recent developments in aquaporin-based membranes. Finally we outline future prospects of aquaporin based biomimetic membrane for desalination and water reuse....

  1. Hydroxyapatite from fish scale for potential use as bone scaffold or regenerative material

    Energy Technology Data Exchange (ETDEWEB)

    Pon-On, Weeraphat, E-mail: fsciwpp@ku.ac.th [Department of Physics, Faculty of Science, Kasetsart University, Bangkok (Thailand); Suntornsaratoon, Panan [Center of Calcium and Bone Research, Faculty of Science, Mahidol University, Bangkok (Thailand); Charoenphandhu, Narattaphol [Center of Calcium and Bone Research, Faculty of Science, Mahidol University, Bangkok (Thailand); Department of Physiology, Faculty of Science, Mahidol University, Bangkok (Thailand); Thongbunchoo, Jirawan [Center of Calcium and Bone Research, Faculty of Science, Mahidol University, Bangkok (Thailand); Krishnamra, Nateetip [Center of Calcium and Bone Research, Faculty of Science, Mahidol University, Bangkok (Thailand); Department of Physiology, Faculty of Science, Mahidol University, Bangkok (Thailand); Tang, I. Ming [Department of Materials Science, Faculty of Science, Kasetsart University, Bangkok 10900 (Thailand)

    2016-05-01

    The present paper studies the physico-chemical, bioactivity and biological properties of hydroxyapatite (HA) which is derived from fish scale (FS) (FSHA) and compares them with those of synthesized HA (sHA) obtained by co-precipitation from chemical solution as a standard. The analysis shows that the FSHA is composed of flat-plate nanocrystal with a narrow width size of about 15–20 nm and having a range of 100 nm in length and that the calcium phosphate ratio (Ca/P) is 2.01 (Ca-rich CaP). Whereas, synthesized HA consists of sub-micron HA particle having a Ca/P ratio of 1.65. Bioactivity test shows that the FSHA forms more new apatite than does the sHA after being incubated in simulated body fluid (SBF) for 7 days. Moreover, the biocompatibility study shows a higher osteoblast like cell adhesion on the FSHA surface than on the sHA substrate after 3 days of culturing. Our results also show the shape of the osteoblast cells on the FSHA changes from being a rounded shape to being a flattened shape reflecting its spreading behavior on this surface. MTT assay and ALP analysis show significant increases in the proliferation and activity of osteoblasts over the FSHA scaffold after 5 days of culturing as compared to those covering the sHA substrates. These results confirm that the bio-materials derived from fish scale (FSHA) are biologically better than the chemically synthesized HA and have the potential for use as a bone scaffold or as regenerative materials. - Highlights: • Preparation of hydroxyapatite (HA) which is derived from fish scale (FS) (FSHA) and their bioactivities • The FSHA is composed of flat-plate nanocrystal with a narrow size of 15–20 nm. • Bioactivity test shows that the FSHA forms more new apatite than does the sHA after being incubated SBF. • In vitro cell availability tests show a higher cell adhesion on the FSHA surface.

  2. Biomimetically-mineralized composite coatings on titanium functionalized with gelatin methacrylate hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Guoxin, E-mail: tanguoxin@126.com [School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006 (China); Zhou, Lei [School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006 (China); Ning, Chengyun, E-mail: imcyning@scut.edu.cn [College of Materials Science and Technology, South China University of Technology, Guangzhou, 510641 (China); Tan, Ying [School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006 (China); Ni, Guoxin [Department of Orthopedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515 (China); Liao, Jingwen; Yu, Peng; Chen, Xiaofeng [College of Materials Science and Technology, South China University of Technology, Guangzhou, 510641 (China)

    2013-08-15

    Immobilizing organic–inorganic hybrid composites onto the implant surface is a promising strategy to improve host acceptance of the implant. The objective of this present study was to obtain a unique macroporous titanium-surface with the organic–mineral composite coatings consisting of gelatin methacrylate hydrogel (GelMA) and hydroxyapatite (HA). A 3-(trimethoxysilyl) propyl methacrylate (TMSPMA) layer was first coated onto the titanium surface, and surface was then covalently functionalized with GelMA using a photochemical method. Mineralization of the GelMA coating on the titanium surface was subsequently carried out by a biomimetic method. After 3-day mineralization, a large number of mineral phases comprising spherical amorphous nanoparticles were found randomly deposited inside GelMA matrix. The resulting mineralized hydrogel composites exhibited a unique rough surface of macroporous structure. The structure of the prepared GelMA/HA composite coating was studied by field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectra (EDS), attenuated total refraction Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Water contact angle measurement revealed the hydrophilicity properties of composite coatings. GelMA/HA on titanium after the TMSPMA treatment is very stable when tested in vitro with a PBS solution at 37 °C, due to the role of TMSPMA as a molecular bridge. It was expected that the macroporous GelMA/HA composite coatings might potentially promote and accelerate titanium (Ti)-based implants osseointegration for bone repair and regeneration.

  3. [Biomimetic nanohydroxyapatite/gelatin composite material preparation and in vitro study].

    Science.gov (United States)

    Li, Siriguleng; Hu, Xiaowen

    2014-09-01

    To prepare nHA/gelatin porous scaffold and to evaluate its physical and chemical properties and biocompatibility. We used nano-powders of HA and gelatin to prepare 3D porous composite scaffold by freeze-drying technique, and used scanning electron microscope, fourier transform infrared spectroscopy and universal testing machine to characterize the composite material. Osteoblasts were primarily cultured, and the third-passage osteoblasts were co-cultured with the composite material. The cell adhesion and morphology were examined under scanning electron microscope. The cell viability analysis was performed by MTT assay, and the alkaline phosphatase activity was measured with alkaline phosphatase kit. Scanning electron microscope showed that the scaffold possessed a 3-dimensional interconnected homogenous porous structure with pore sizes ranging from 150 to 400 μm. Fourier transform infrared spectroscopy showed that the composite material had a strong chemical bond between the inorganic phase and organic phase. The scaffold presented the compressive strength of (3.28 ± 0.51) MPa and porosities of (80.6 ± 4.1)%. Composite materials showed features of had good biocompatibility. Mouse osteoblasts were well adhered and spread on the materials. The grade of the cell toxicity ranged from I to II. On the 5th and 7th day the proliferative rate of osteoblasts on scaffolds in the composite materials was significantly higher than that in the control group. The activity of alkaline phosphatase was obviously higher than that in the control group on Day 1 and 3. Nano-hydroxyapatite and gelatin in certain proportions and under certain conditions can be prepared into a composite biomimetic porous scaffolds with high porosity and three-dimensional structure using freeze-drying method. The scaffold shows good biocompatibility with mouse osteoblasts and may be a novel scaffolds for bone tissue engineering.

  4. Structure and transformation of tactoids in cellulose nanocrystal suspensions

    Science.gov (United States)

    Wang, Pei-Xi; Hamad, Wadood Y.; MacLachlan, Mark J.

    2016-05-01

    Cellulose nanocrystals obtained from natural sources are of great interest for many applications. In water, cellulose nanocrystals form a liquid crystalline phase whose hierarchical structure is retained in solid films after drying. Although tactoids, one of the most primitive components of liquid crystals, are thought to have a significant role in the evolution of this phase, they have evaded structural study of their internal organization. Here we report the capture of cellulose nanocrystal tactoids in a polymer matrix. This method allows us to visualize, for the first time, the arrangement of cellulose nanocrystals within individual tactoids by electron microscopy. Furthermore, we can follow the structural evolution of the liquid crystalline phase from tactoids to iridescent-layered films. Our insights into the early nucleation events of cellulose nanocrystals give important information about the growth of cholesteric liquid crystalline phases, especially for cellulose nanocrystals, and are crucial for preparing photonics-quality films.

  5. Synthesis of hydroxyapatite nanoparticles onto modified polypropylene surface to be used in bone tissue engineering

    International Nuclear Information System (INIS)

    Cellet, Thelma Sley P.; Pereira, Guilherme M.; Fragal, Elizangela H.; Rubira, Adley F.; Companhoni, Mychelle V.P.; Nakamura, Celso V.; Ueda-Nakamura, Tania

    2015-01-01

    Chemical modification of polypropylene (PP) films can be explored to prepare innovative materials, for instance materials which can be used in tissue engineering application. The maleimide synthesis onto PP films was made for later polymerizes glycidyl methacrylate (GMA) and to grow up hydroxyapatite nanoparticles (n-HA) by biomimetization method (BM) in metastable simulated body fluid (SBF) for 7, 14 and 21 days. The modification steps were proved by infrared spectroscopy (FTIR) and the n-HA synthesis evidenced by X-ray diffractometry (XRD), scanning electronic microscopy (SEM) and energy dispersive spectroscopy (EDS). PP films exposed to SBF for 14 and 21 days showed n-HA on all over the films surface. The interaction of pre-osteoblasts with the films after 48 hours was evaluated by SEM. The results demonstrate that cells on the surface of n-HA films showed spreading, and number of filopodia similar to the control, wherein the films with greater amount of n-HA appear to have higher filopodia connections between the cells and appear to have its surface covered with higher cell density. (author)

  6. Assembly of Layered Monetite-Chitosan Nanocomposite and Its Transition to Organized Hydroxyapatite.

    Science.gov (United States)

    Ruan, Qichao; Liberman, David; Zhang, Yuzheng; Ren, Dongni; Zhang, Yunpeng; Nutt, Steven; Moradian-Oldak, Janet

    2016-06-13

    Bioinspired synthesis of hierarchically structured calcium phosphate (CaP) material is a highly promising strategy for developing improved bone substitute materials. However, synthesis of CaP materials with outstanding mechanical properties still remains an ongoing challenge. Inspired by the formation of lamellar structure in nacre, we designed an organic matrix composed of chitosan and cis-butenediolic acid (maleic acid, MAc) that could assemble into a layered complex and further guide the mineralization of monetite crystals, resulting in the formation of organized and parallel arrays of monetite platelets with a brick-and-mortar structure. Using the layered monetite-chitosan composite as a precursor, we were able to synthesize hydroxyapatite (HAp) with multiscale hierarchically ordered structure via a topotactic phase transformation process. On the nanoscale, needlelike HAp crystallites assembled into organized bundles that aligned to form highly oriented plates on the microscale. On the large-scale level, these plates with different crystal orientations were stacked together to form a layered structure. The organized structures and composite feature yielded CaP materials with improved mechanical properties close to those of bone. Our study introduces a biomimetic approach that may be practical for the design of advanced, mechanically robust materials for biomedical applications.

  7. Biologically inspired growth of hydroxyapatite crystals on bio-organics-defined scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Chunrong, E-mail: milkhoney3@163.com [Department of Materials Science and Engineering, Fujian University of Technology, Fuzhou 350108 (China); Li, Yuli; Nan, Kaihui [Eye Hospital, Wenzhou Medical College, Wenzhou 325027 (China)

    2013-03-15

    Graphical abstract: Petal-like crystals were observed to form on the surface of the BG/COL/ChS scaffolds. Highlights: ► Porous scaffolds were prepared using bioglass, collagen and chondroitin sulfate. ► Highly oriented HA crystals were grown on scaffolds using simulated body fluids ► The microstructure and orientation of HA were explained by molecular configuration. - Abstract: Several bio-organics-defined composite scaffolds were prepared using 58s-bioglass (BG), collagen (Col) and chondroitin sulfate (ChS). These scaffolds possess highly porous structure. X-ray diffraction of these scaffolds strongly indicated that hydroxyapatite (HA) crystals formed on their surfaces in simulated body fluids within 3 d, and similar formation process of crystals could be obtained on BG/Col and BG/Col/ChS scaffolds. The morphology and structure of the crystals were further examined by scanning electron microscopy. The results obtained indicate that an apatite with petal-like structure similar to that found on BG/Col scaffolds can be produced on BG/Col/ChS scaffolds through biomimetic synthesis, while that on BG/ChS scaffolds took place differently. The differences could be explained by self-assembly processes and the different macromolecular configurations of the Col and ChS fibrils which self-assemble spontaneously into their fibers. On the other hand, the bio-organics-defined composites have good cell biocompability. The results may be applicable to develop tailored biomaterials for peculiar bone substitute.

  8. Biologically inspired growth of hydroxyapatite crystals on bio-organics-defined scaffolds

    International Nuclear Information System (INIS)

    Yang, Chunrong; Li, Yuli; Nan, Kaihui

    2013-01-01

    Graphical abstract: Petal-like crystals were observed to form on the surface of the BG/COL/ChS scaffolds. Highlights: ► Porous scaffolds were prepared using bioglass, collagen and chondroitin sulfate. ► Highly oriented HA crystals were grown on scaffolds using simulated body fluids ► The microstructure and orientation of HA were explained by molecular configuration. - Abstract: Several bio-organics-defined composite scaffolds were prepared using 58s-bioglass (BG), collagen (Col) and chondroitin sulfate (ChS). These scaffolds possess highly porous structure. X-ray diffraction of these scaffolds strongly indicated that hydroxyapatite (HA) crystals formed on their surfaces in simulated body fluids within 3 d, and similar formation process of crystals could be obtained on BG/Col and BG/Col/ChS scaffolds. The morphology and structure of the crystals were further examined by scanning electron microscopy. The results obtained indicate that an apatite with petal-like structure similar to that found on BG/Col scaffolds can be produced on BG/Col/ChS scaffolds through biomimetic synthesis, while that on BG/ChS scaffolds took place differently. The differences could be explained by self-assembly processes and the different macromolecular configurations of the Col and ChS fibrils which self-assemble spontaneously into their fibers. On the other hand, the bio-organics-defined composites have good cell biocompability. The results may be applicable to develop tailored biomaterials for peculiar bone substitute

  9. Bioactive hydroxyapatite/graphene composite coating and its corrosion stability in simulated body fluid

    Energy Technology Data Exchange (ETDEWEB)

    Janković, Ana; Eraković, Sanja [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11 000 Belgrade (Serbia); Mitrić, Miodrag [Vinča Institute of Nuclear Sciences, University of Belgrade, Mike Petrovića Alasa 12-14, 11 000 Belgrade (Serbia); Matić, Ivana Z.; Juranić, Zorica D. [Institute of Oncology and Radiology of Serbia, Pasterova 14, 11 000 Belgrade (Serbia); Tsui, Gary C.P.; Tang, Chak-yin [Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China); Mišković-Stanković, Vesna [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11 000 Belgrade (Serbia); Rhee, Kyong Yop, E-mail: rheeky@khu.ac.kr [Department of Mechanical Engineering, Kyung Hee University, Yongin 449-701 (Korea, Republic of); Park, Soo Jin [Chemistry, College of Natural Sciences, Inha University, Incheon 402-751 (Korea, Republic of)

    2015-03-05

    Highlights: • Bioactive HAP/Gr coating on Ti was successfully obtained by EPD. • Increased fracture toughness of the HAP/Gr coating compared to pure HAP coating. • HAP/Gr coating exhibited superior biomimetic mineralization vs. pure HAP coating. • Gr improved the mechanical properties and thermal stability of HAP/Gr coating. • HAP/Gr coating was classified as non-cytotoxic against the targeted PBMC. - Abstract: The hydroxyapatite/graphene (HAP/Gr) composite was electrodeposited on Ti using the electrophoretic deposition process to obtain uniform bioactive coating with improved mechanical strength and favorable corrosion stability in simulated body fluid (SBF). Incorporation of Gr was verified by Raman spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray photoelectron analysis. The HAP/Gr composite coating exhibited reduced surface cracks, nearly double the hardness, and elastic modulus increased by almost 50% compared to pure HAP coating, as estimated by a nanoindentation test. The bioactive HAP/Gr composite coating provided a newly formed apatite layer in SBF with enhanced corrosion stability, as evidenced by electrochemical impedance spectroscopy. The thermal stability of the HAP/Gr coating was improved in comparison to the pure HAP coating, and the Ca/P ratio was closer to the stoichiometric value. No antibacterial activity against Staphylococcus aureus or Escherichia coli could be verified. The HAP/Gr composite coating was classified as non-cytotoxic when tested against healthy peripheral blood mononuclear cells (PBMC)

  10. Bioactive hydroxyapatite/graphene composite coating and its corrosion stability in simulated body fluid

    International Nuclear Information System (INIS)

    Janković, Ana; Eraković, Sanja; Mitrić, Miodrag; Matić, Ivana Z.; Juranić, Zorica D.; Tsui, Gary C.P.; Tang, Chak-yin; Mišković-Stanković, Vesna; Rhee, Kyong Yop; Park, Soo Jin

    2015-01-01

    Highlights: • Bioactive HAP/Gr coating on Ti was successfully obtained by EPD. • Increased fracture toughness of the HAP/Gr coating compared to pure HAP coating. • HAP/Gr coating exhibited superior biomimetic mineralization vs. pure HAP coating. • Gr improved the mechanical properties and thermal stability of HAP/Gr coating. • HAP/Gr coating was classified as non-cytotoxic against the targeted PBMC. - Abstract: The hydroxyapatite/graphene (HAP/Gr) composite was electrodeposited on Ti using the electrophoretic deposition process to obtain uniform bioactive coating with improved mechanical strength and favorable corrosion stability in simulated body fluid (SBF). Incorporation of Gr was verified by Raman spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray photoelectron analysis. The HAP/Gr composite coating exhibited reduced surface cracks, nearly double the hardness, and elastic modulus increased by almost 50% compared to pure HAP coating, as estimated by a nanoindentation test. The bioactive HAP/Gr composite coating provided a newly formed apatite layer in SBF with enhanced corrosion stability, as evidenced by electrochemical impedance spectroscopy. The thermal stability of the HAP/Gr coating was improved in comparison to the pure HAP coating, and the Ca/P ratio was closer to the stoichiometric value. No antibacterial activity against Staphylococcus aureus or Escherichia coli could be verified. The HAP/Gr composite coating was classified as non-cytotoxic when tested against healthy peripheral blood mononuclear cells (PBMC)

  11. Hydroxyapatite/polylactide biphasic combination scaffold loaded with dexamethasone for bone regeneration.

    Science.gov (United States)

    Son, Jun-Sik; Kim, Su-Gwan; Oh, Ji-Su; Appleford, Mark; Oh, Sunho; Ong, Joo L; Lee, Kyu-Bok

    2011-12-15

    This study presents a novel design of a ceramic/polymer biphasic combination scaffold that mimics natural bone structures and is used as a bone graft substitute. To mimic the natural bone structures, the outside cortical-like shells were composed of porous hydroxyapatite (HA) with a hollow interior using a polymeric template-coating technique; the inner trabecular-like core consisted of porous poly(D,L-lactic acid) (PLA) that was loaded with dexamethasone (DEX) and was directly produced using a particle leaching/gas forming technique to create the inner diameter of the HA scaffold. It was observed that the HA and PLA parts of the fabricated HA/PLA biphasic scaffold contained open and interconnected pore structures, and the boundary between both parts was tightly connected without any gaps. It was found that the structure of the combination scaffold was analogous to that of natural bone based on micro-computed tomography analysis. Additionally, the dense, uniform apatite layer was formed on the surface of the HA/PLA biphasic scaffold through a biomimetic process, and DEX was successfully released from the PLA of the biphasic scaffold over a 1-month period. This release caused human embryonic palatal mesenchyme cells to proliferate, differentiate, produce ECM, and form tissue in vitro. Therefore, it was concluded that this functionally graded scaffold is similar to natural bone and represents a potential bone-substitute material. Copyright © 2011 Wiley Periodicals, Inc.

  12. Biomimetic self-assembly of a functional asymmetrical electronic device.

    Science.gov (United States)

    Boncheva, Mila; Gracias, David H; Jacobs, Heiko O; Whitesides, George M

    2002-04-16

    This paper introduces a biomimetic strategy for the fabrication of asymmetrical, three-dimensional electronic devices modeled on the folding of a chain of polypeptide structural motifs into a globular protein. Millimeter-size polyhedra-patterned with logic devices, wires, and solder dots-were connected in a linear string by using flexible wire. On self-assembly, the string folded spontaneously into two domains: one functioned as a ring oscillator, and the other one as a shift register. This example demonstrates that biomimetic principles of design and self-organization can be applied to generate multifunctional electronic systems of complex, three-dimensional architecture.

  13. Biomimetic actuators using electroactive polymers (EAP) as artificial muscles

    Science.gov (United States)

    Bar-Cohen, Yoseph

    2006-01-01

    Evolution has resolved many of nature's challenges leading to lasting solutions with maximal performance and effective use of resources. Nature's inventions have always inspired human achievements leading to effective materials, structures, tools, mechanisms, processes, algorithms, methods, systems and many other benefits. The field of mimicking nature is known as Biomimetics and one of its topics includes electroactive polymers that gain the moniker artificial muscles. Integrating EAP with embedded sensors, self-repair and many other capabilities that are used in composite materials can add greatly to the capability of smart biomimetic systems. Such development would enable fascinating possibilities potentially turning science fiction ideas into engineering reality.

  14. Organization of silicon nanocrystals by localized electrochemical etching

    International Nuclear Information System (INIS)

    Ayari-Kanoun, Asma; Drouin, Dominique; Beauvais, Jacques; Lysenko, Vladimir; Nychyporuk, Tetyana; Souifi, Abdelkader

    2009-01-01

    An approach to form a monolayer of organized silicon nanocrystals on a monocrystalline Si wafer is reported. Ordered arrays of nanoholes in a silicon nitride layer were obtained by combining electron beam lithography and plasma etching. Then, a short electrochemical etching current pulse led to formation of a single Si nanocrystal per each nanohole. As a result, high quality silicon nanocrystal arrays were formed with well controlled and reproducible morphologies. In future, this approach can be used to fabricate single electron devices.

  15. Microscopic theory of cation exchange in CdSe nanocrystals.

    Science.gov (United States)

    Ott, Florian D; Spiegel, Leo L; Norris, David J; Erwin, Steven C

    2014-10-10

    Although poorly understood, cation-exchange reactions are increasingly used to dope or transform colloidal semiconductor nanocrystals (quantum dots). We use density-functional theory and kinetic Monte Carlo simulations to develop a microscopic theory that explains structural, optical, and electronic changes observed experimentally in Ag-cation-exchanged CdSe nanocrystals. We find that Coulomb interactions, both between ionized impurities and with the polarized nanocrystal surface, play a key role in cation exchange. Our theory also resolves several experimental puzzles related to photoluminescence and electrical behavior in CdSe nanocrystals doped with Ag.

  16. Study of sorption processes of strontium on the synthetic hydroxyapatite

    International Nuclear Information System (INIS)

    Rosskopfova, O.; Galambos, M.; Rajec, P.

    2011-01-01

    The sorption of strontium on synthetic hydroxyapatite was investigated using batch method and radiotracer technique. The hydroxyapatite samples were prepared by a wet precipitation process followed by calcination of calcium phosphate that precipitated from aqueous solution. Also, commercial hydroxyapatites were used. The sorption of strontium on hydroxyapatite depended on the method of preparation and it was pH independent ranging from 4 to 9 as a result of buffering properties of hydroxyapatite. The distribution coefficient K d was significantly decreased with increasing concentration of Sr 2+ and Ca 2+ ions in solution with concentration above 1 x 10 -3 mol dm -3 . The percentage strontium sorption for commercial and by wet method prepared hydroxyapatite was in the range of 83-96%, while calcined hydroxyapatite was ranging from 10 to 30%. The experimental data for sorption of strontium have been interpreted in the term of Langmuir isotherm. The sorption of Sr 2+ ions was performed by ion-exchange with Ca 2+ cations on the crystal surface of hydroxyapatite. Although calcined hydroxyapatite is successfully used as biomaterial for hard tissues repair, it is not used for the treatment of liquid wastes. (author)

  17. Mechanical properties and biocompatibility of the sputtered Ti doped hydroxyapatite.

    Science.gov (United States)

    Vladescu, A; Padmanabhan, S C; Ak Azem, F; Braic, M; Titorencu, I; Birlik, I; Morris, M A; Braic, V

    2016-10-01

    The hydroxyapatite enriched with Ti were prepared as possible candidates for biomedical applications especially for implantable devices that are in direct contact to the bone. The hydroxyapatites with different Ti content were prepared by RF magnetron sputtering on Ti-6Al-4V alloy using pure hydroxyapatite and TiO2 targets. The content of Ti was modified by changing the RF power fed on TiO2 target. The XPS and FTIR analyses revealed the presence of hydroxyapatite structure. The hardness and elastic modulus of the hydroxyapatite were increased by Ti addition. After 5 days of culture, the cell viability of the Ti-6Al-4V was enhanced by depositing with undoped or doped hydroxyapatite. The Ti additions led to an increase in cell viability of hydroxyapatite, after 5 days of culture. The electron microscopy showed the presence of more cells on the surface of Ti-enriched hydroxyapatite than those observed on the surface of the uncoated alloys or undoped hydroxyapatite. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Development of hydroxyapatite/polyvinyl alcohol bionanocomposite for prosthesis implants

    Science.gov (United States)

    Karthik, V.; Pabi, S. K.; Chowdhury, S. K. Roy

    2018-02-01

    Hydroxyapatite (Ca10(PO4)6(OH)2) has similar structural and chemical properties of natural bone mineral and hence widely used as a bone replacement substitute. Natural bone consists of hydroxyapatite and collagen. For mimicking the natural, in the present work, a sintered porous hydroxyapatite component has been vacuum impregnated with Polyvinyl alcohol (PVA), which has better properties like biocompatibility, biodegradability and water- solubility. Hydroxyapatite powders have been made into nanosize to reduce the melting point and hence the sintering temperature. In the present investigation high energy ball mill is used to produce nano-hydroxyapatite powders in bulk quantity by optimizing the milling parameters using stainless steel grinding media. Pellets of 10 mm diameter have been produced from nano- hydroxyapatite powders under different uniaxial compaction pressures. The pellets have been sintered to form porous compacts. The vacuum impregnation of sintered pallets with PVA solution of different strength has been done to find the optimum impregnation condition. Microhardness, compressive strength, wear loss and haemocompatibility of hydroxyapatite ceramics have been studied before and after impregnation of PVA. The nano- hydroxyapatite/PVA composites have superior mechanical properties and reduced wear loss than the non-impregnated porous nano-hydroxyapatite ceramics.

  19. Biomimetic processing of oriented crystalline ceramic layers

    Energy Technology Data Exchange (ETDEWEB)

    Cesarano, J.; Shelnutt, J.A.

    1997-10-01

    The aim of this project was to develop the capabilities for Sandia to fabricate self assembled Langmuir-Blodgett (LB) films of various materials and to exploit their two-dimensional crystalline structure to promote the growth of oriented thin films of inorganic materials at room temperature. This includes the design and synthesis of Langmuir-active (amphiphilic) organic molecules with end groups offering high nucleation potential for various ceramics. A longer range goal is that of understanding the underlying principles, making it feasible to use the techniques presented in this report to fabricate unique oriented films of various materials for electronic, sensor, and membrane applications. Therefore, whenever possible, work completed in this report was completed with the intention of addressing the fundamental phenomena underlying the growth of crystalline, inorganic films on template layers of highly organized organic molecules. This problem was inspired by biological processes, which often produce exquisitely engineered structures via templated growth on polymeric layers. Seashells, for example, exhibit great toughness owing to their fine brick-and-mortar structure that results from templated growth of calcium carbonate on top of layers of ordered organic proteins. A key goal in this work, therefore, is to demonstrate a positive correlation between the order and orientation of the template layer and that of the crystalline ceramic material grown upon it. The work completed was comprised of several parallel efforts that encompassed the entire spectrum of biomimetic growth from solution. Studies were completed on seashells and the mechanisms of growth for calcium carbonate. Studies were completed on the characterization of LB films and the capability developed for the in-house fabrication of these films. Standard films of fatty acids were studied as well as novel polypeptides and porphyrins that were synthesized.

  20. Biomimetic catalysts responsive to specific chemical signals

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yan [Iowa State Univ., Ames, IA (United States)

    2015-03-04

    Part 1. Design of Biomimetic Catalysts Based on Amphiphilic Systems The overall objective of our research is to create biomimetic catalysts from amphiphilic molecules. More specifically, we aim to create supramolecular systems that can be used to control the microenvironment around a catalytic center in a biomimetic fashion and apply the learning to construct supramolecular catalysts with novel functions found in enzymatic catalysts. We have prepared synthetic molecules (i.e., foldamers) that could fold into helical structures with nanometer-sized internal hydrophilic cavities. Cavities of this size are typically observed only in the tertiary and quaternary structures of proteins but were formed in our foldamer prepared in just a few steps from the monomer. Similar to many proteins, our foldamers displayed cooperativity in the folding/unfolding equilibrium and followed a two-state conformational transition. In addition, their conformational change could be triggered by solvent polarity, pH, or presence of metal ions and certain organic molecules. We studied their environmentally dependent conformational changes in solutions, surfactant micelles, and lipid bilayer membranes. Unlike conventional rigid supramolecular host, a foldamer undergoes conformational change during guest binding. Our study in the molecular recognition of an oligocholate host yielded some extremely exciting results. Cooperativity between host conformation and host–guest interactions was found to “magnify” weak binding interactions. In other words, since binding affinity is determined by the overall change of free energy during the binding, guest-induced conformational change of the host, whether near or far from the binding site, affects the binding. This study has strong implications in catalysis because enzymes have been hypothesized to harvest similar intramolecular forces to strengthen their binding with the transition state of an enzyme-catalyzed reaction. The supramolecular and

  1. Cellulose nanocrystal properties and their applications

    Directory of Open Access Journals (Sweden)

    mahdi jonoobi

    2015-05-01

    Full Text Available The main purpose of this work is to provide an overview of recent research in the area of cellulose nonmaterials production from different sources. Due to their abundance, their renewability, high strength and stiffness, being eco-friendly, and low weight; numerous studies have been reported on the isolation of cellulose nanomaterials from different cellulosic sources and their use in high performance applications. This work covers an introduction into the nano cellulose definition as well as used methods for isolation of nanomaterials (nanocrystals from various sources. The rod-like cellulose nanocrystals (CNC can be isolated from sources like wood, plant fibers, agriculture and industrial bio residues, tunicates, and bacterial cellulose using acid hydrolysis process. Following this, the paper focused on characterization methods, materials properties and structure. The current review is a comprehensive literature regarding the nano cellulose isolation and demonstrates the potential of cellulose nanomaterials to be used in a wide range of high-tech applications.

  2. Tunable plasmonic lattices of silver nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Andrea; Sinsermsuksakul, Prasert; Yang, Peidong

    2008-02-18

    Silver nanocrystals are ideal building blocks for plasmonicmaterials that exhibit a wide range of unique and potentially usefuloptical phenomena. Individual nanocrystals display distinct opticalscattering spectra and can be assembled into hierarchical structures thatcouple strongly to external electromagnetic fields. This coupling, whichis mediated by surface plasmons, depends on their shape and arrangement.Here we demonstrate the bottom-up assembly of polyhedral silvernanocrystals into macroscopic two-dimensional superlattices using theLangmuir-Blodgett technique. Our ability to control interparticlespacing, density, and packing symmetry allows for tunability of theoptical response over the entire visible range. This assembly strategyoffers a new, practical approach to making novel plasmonic materials forapplication in spectroscopic sensors, sub-wavelength optics, andintegrated devices that utilize field enhancement effects.

  3. Hydroxyapatite Fibers: A Review of Synthesis Methods

    Science.gov (United States)

    Qi, Mei-Li; He, Kun; Huang, Zhen-Nan; Shahbazian-Yassar, Reza; Xiao, Gui-Yong; Lu, Yu-Peng; Shokuhfar, Tolou

    2017-08-01

    Hydroxyapatite (HA) exhibits excellent biocompatibility, bioactivity, osteoconductivity, non-toxicity and so on, making it a perfect candidate for biomedical applications. However, HA is not qualified to be used in load-bearing sites due to its poor flexural strength and fracture toughness. Design, synthesis and application of fibrous HA is a promising strategy to overcome the inherent brittleness. This review provides a brief description of HA and hydroxyapatite fiber (HAF), then introduces different synthesis methods of HAF and highlights the inherent merits and drawbacks involved in each method. Finally, the future perspectives in this active research area are given. The purpose of this review is to acquaint the reader with this promising new field of biomaterials research and with emphasis on recent techniques to obtain continuous, uniform and long HAF.

  4. Strontium hydroxyapatite/chitosan nanohybrid scaffolds with enhanced osteoinductivity for bone tissue engineering.

    Science.gov (United States)

    Lei, Yong; Xu, Zhengliang; Ke, Qinfei; Yin, Wenjing; Chen, Yixuan; Zhang, Changqing; Guo, Yaping

    2017-03-01

    For the clinical application of bone tissue engineering with the combination of biomaterials and mesenchymal stem cells (MSCs), bone scaffolds should possess excellent biocompatibility and osteoinductivity to accelerate the repair of bone defects. Herein, strontium hydroxyapatite [SrHAP, Ca 10-x Sr x (PO 4 ) 6 (OH) 2 ]/chitosan (CS) nanohybrid scaffolds were fabricated by a freeze-drying method. The SrHAP nanocrystals with the different x values of 0, 1, 5 and 10 are abbreviated to HAP, Sr1HAP, Sr5HAP and Sr10HAP, respectively. With increasing x values from 0 to 10, the crystal cell volumes and axial lengths of SrHAP become gradually large because of the greater ion radius of Sr 2+ than Ca 2+ , while the crystal sizes of SrHAP decrease from 70.4nm to 46.7nm. The SrHAP/CS nanohybrid scaffolds exhibits three-dimensional (3D) interconnected macropores with pore sizes of 100-400μm, and the SrHAP nanocrystals are uniformly dispersed within the scaffolds. In vitro cell experiments reveal that all the HAP/CS, Sr1HAP/CS, Sr5HAP/CS and Sr10HAP/CS nanohybrid scaffolds possess excellent cytocompatibility with the favorable adhesion, spreading and proliferation of human bone marrow mesenchymal stem cells (hBMSCs). The Sr5HAP nanocrystals in the scaffolds do not affect the adhesion, spreading of hBMSCs, but they contribute remarkably to cell proliferation and osteogenic differentiation. As compared with the HAP/CS nanohybrid scaffold, the released Sr 2+ ions from the SrHAP/CS nanohybrid scaffolds enhance alkaline phosphatase (ALP) activity, extracellular matrix (ECM) mineralization and osteogenic-related COL-1 and ALP expression levels. Especially, the Sr5HAP/CS nanohybrid scaffolds exhibit the best osteoinductivity among four groups because of the synergetic effect between Ca 2+ and Sr 2+ ions. Hence, the Sr5HAP/CS nanohybrid scaffolds with excellent cytocompatibility and osteogenic property have promising application for bone tissue engineering. Copyright © 2016. Published

  5. FIBROUS SILICA-HYDROXYAPATITE COMPOSITE BY ELECTROSPINNING

    OpenAIRE

    Jesús Alberto Garibay-Alvarado; León Francisco Espinosa-Cristóbal; Simón Yobanny Reyes-López

    2017-01-01

    New nanocomposite membrane was fabricated by electrospinning. The nanocomposite combines a glass and hydroxyapatite (HA). This research proposed the incorporation of glass to counteract the brittleness of HA in a composite formed by coaxial fibers which will be used for bone replacement. Calcium phosphate ceramics are used widely for dental and orthopedic reasons, because they can join tightly through chemical bonds and promote bone regeneration. Precursors HA and SiO2 were synthetized throug...

  6. Bio-Mimetic Sensors Based on Molecularly Imprinted Membranes

    Science.gov (United States)

    Algieri, Catia; Drioli, Enrico; Guzzo, Laura; Donato, Laura

    2014-01-01

    An important challenge for scientific research is the production of artificial systems able to mimic the recognition mechanisms occurring at the molecular level in living systems. A valid contribution in this direction resulted from the development of molecular imprinting. By means of this technology, selective molecular recognition sites are introduced in a polymer, thus conferring it bio-mimetic properties. The potential applications of these systems include affinity separations, medical diagnostics, drug delivery, catalysis, etc. Recently, bio-sensing systems using molecularly imprinted membranes, a special form of imprinted polymers, have received the attention of scientists in various fields. In these systems imprinted membranes are used as bio-mimetic recognition elements which are integrated with a transducer component. The direct and rapid determination of an interaction between the recognition element and the target analyte (template) was an encouraging factor for the development of such systems as alternatives to traditional bio-assay methods. Due to their high stability, sensitivity and specificity, bio-mimetic sensors-based membranes are used for environmental, food, and clinical uses. This review deals with the development of molecularly imprinted polymers and their different preparation methods. Referring to the last decades, the application of these membranes as bio-mimetic sensor devices will be also reported. PMID:25196110

  7. Biomimetics and the case of the remarkable ragworms

    Science.gov (United States)

    Hesselberg, Thomas

    2007-08-01

    Biomimetics is a rapidly growing field both as an academic and as an applied discipline. This paper gives a short introduction to the current status of the discipline before it describes three approaches to biomimetics: the mechanism-driven, which is based on the study of a specific mechanism; the focused organism-driven, which is based on the study of one function in a model organism; and the integrative organism-driven approach, where multiple functions of a model organism provide inspiration. The first two are established approaches and include many modern studies and the famous biomimetic discoveries of Velcro and the Lotus-Effect, whereas the last approach is not yet well recognized. The advantages of the integrative organism-driven approach are discussed using the ragworms as a case study. A morphological and locomotory study of these marine polychaetes reveals their biomimetic potential, which includes using their ability to move in slippery substrates as inspiration for novel endoscopes, using their compound setae as models for passive friction structures and using their three gaits, slow crawling, fast crawling, and swimming as well as their rapid burrowing technique to provide inspiration for the design of displacement pumps and multifunctional robots.

  8. Phospholipid-sepiolite biomimetic interfaces for the immobilization of enzymes.

    Science.gov (United States)

    Wicklein, Bernd; Darder, Margarita; Aranda, Pilar; Ruiz-Hitzky, Eduardo

    2011-11-01

    Biomimetic interfaces based on phosphatidylcholine (PC) assembled to the natural silicate sepiolite were prepared for the stable immobilization of the urease and cholesterol oxidase enzymes. This is an important issue in practical advanced applications such as biocatalysis or biosensing. The supported lipid bilayer (BL-PC), prepared from PC adsorption, was used for immobilization of enzymes and the resulting biomimetic systems were compared to several other supported layers including a lipid monolayer (ML-PC), a mixed phosphatidylcholine/octyl-galactoside layer (PC-OGal), a cetyltrimethylammonium monolayer (CTA), and also to the bare sepiolite surface. Interfacial characteristics of these layers were investigated with a focus on layer packing density, hydrophilicity/hydrophobicity, and surface charge, which are being considered as key points for enzyme immobilization and stabilization of their biological activity. Cytoplasmic urease and membrane-bound cholesterol oxidase, which served as model enzymes, were immobilized on the different PC-based hybrid materials to probe their biomimetic character. Enzymatic activity was assessed by cyclic voltammetry and UV-vis spectrophotometry. The resulting enzyme/bio-organoclay hybrids were applied as active phase of a voltammetric urea biosensor and cholesterol bioreactor, respectively. Urease supported on sepiolite/BL-PC proved to maintain its enzymatic activity over several months while immobilized cholesterol oxidase demonstrated high reusability as biocatalyst. The results emphasize the good preservation of bioactivity due to the accommodation of the enzymatic system within the biomimetic lipid interface on sepiolite.

  9. Bio-Mimetic Sensors Based on Molecularly Imprinted Membranes

    Directory of Open Access Journals (Sweden)

    Catia Algieri

    2014-07-01

    Full Text Available An important challenge for scientific research is the production of artificial systems able to mimic the recognition mechanisms occurring at the molecular level in living systems. A valid contribution in this direction resulted from the development of molecular imprinting. By means of this technology, selective molecular recognition sites are introduced in a polymer, thus conferring it bio-mimetic properties. The potential applications of these systems include affinity separations, medical diagnostics, drug delivery, catalysis, etc. Recently, bio-sensing systems using molecularly imprinted membranes, a special form of imprinted polymers, have received the attention of scientists in various fields. In these systems imprinted membranes are used as bio-mimetic recognition elements which are integrated with a transducer component. The direct and rapid determination of an interaction between the recognition element and the target analyte (template was an encouraging factor for the development of such systems as alternatives to traditional bio-assay methods. Due to their high stability, sensitivity and specificity, bio-mimetic sensors-based membranes are used for environmental, food, and clinical uses. This review deals with the development of molecularly imprinted polymers and their different preparation methods. Referring to the last decades, the application of these membranes as bio-mimetic sensor devices will be also reported.

  10. Diffraction from relief gratings on a biomimetic elastomer cast

    International Nuclear Information System (INIS)

    Guerrero, Raphael A.; Aranas, Erika B.

    2010-01-01

    Biomimetic optical elements combine the optimized designs of nature with the versatility of materials engineering. We employ a beetle carapace as the template for fabricating relief gratings on an elastomer substrate. Biological surface features are successfully replicated by a direct casting procedure. Far-field diffraction effects are discussed in terms of the Fraunhofer approximation in Fourier space.

  11. Developing the ultimate biomimetic flow-sensor array

    NARCIS (Netherlands)

    Bruinink, C.M.; Jaganatharaja, R.K.; de Boer, Meint J.; Berenschot, Johan W.; Kolster, M.L.; Lammerink, Theodorus S.J.; Wiegerink, Remco J.; Krijnen, Gijsbertus J.M.

    2009-01-01

    This contribution reports on the major developments and achievements in our group on fabricating highly sensitive biomimetic flow-sensor arrays. The mechanoreceptive sensory hairs of crickets are taken as a model system for their ability to perceive flow signals at thermal noise levels and,

  12. Biomimetic calcium phosphate coatings: : Physicochemistry and biological activity

    NARCIS (Netherlands)

    Barrère, F.

    2002-01-01

    Plasma-sprayed hydroxylapatite coatings on metallic prosthesis significantly increased the success rate of hip arthroplasty, namely from about 90% after 10 years for cemented hip stems to 98% for HA coated ones. Nowadays, the biomimetic approach has received increased interest because of the

  13. Biomimetic synthesis of hybrid nanocomposite scaffolds by freeze

    Indian Academy of Sciences (India)

    The aim of this study is to biomimetically synthesize hydroxyapatite–hydrophilic polymer scaffolds for biomedical applications. This organic–inorganic hybrid has been structurally characterized and reveals a good microstructural control as seen by the SEM analysis and the nanosize of the particulates is confirmed by AFM ...

  14. A biomimetic accelerometer inspired by the cricket's clavate hair

    NARCIS (Netherlands)

    Droogendijk, H.; de Boer, Meint J.; Sanders, Remco G.P.; Krijnen, Gijsbertus J.M.

    2014-01-01

    Crickets use so-called clavate hairs to sense (gravitational) acceleration to obtain information on their orientation. Inspired by this clavate hair system, a one-axis biomimetic accelerometer has been developed and fabricated using surface micromachining and SU-8 lithography. An analytical model

  15. Extracting hot carriers from photoexcited semiconductor nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiaoyang

    2014-12-10

    This research program addresses a fundamental question related to the use of nanomaterials in solar energy -- namely, whether semiconductor nanocrystals (NCs) can help surpass the efficiency limits, the so-called “Shockley-Queisser” limit, in conventional solar cells. In these cells, absorption of photons with energies above the semiconductor bandgap generates “hot” charge carriers that quickly “cool” to the band edges before they can be utilized to do work; this sets the solar cell efficiency at a limit of ~31%. If instead, all of the energy of the hot carriers could be captured, solar-to-electric power conversion efficiencies could be increased, theoretically, to as high as 66%. A potential route to capture this energy is to utilize semiconductor nanocrystals. In these materials, the quasi-continuous conduction and valence bands of the bulk semiconductor become discretized due to confinement of the charge carriers. Consequently, the energy spacing between the electronic levels can be much larger than the highest phonon frequency of the lattice, creating a “phonon bottleneck” wherein hot-carrier relaxation is possible via slower multiphonon emission. For example, hot-electron lifetimes as long as ~1 ns have been observed in NCs grown by molecular beam epitaxy. In colloidal NCs, long lifetimes have been demonstrated through careful design of the nanocrystal interfaces. Due to their ability to slow electronic relaxation, semiconductor NCs can in principle enable extraction of hot carriers before they cool to the band edges, leading to more efficient solar cells.

  16. Structural phase transitions in niobium oxide nanocrystals

    Science.gov (United States)

    Yuvakkumar, R.; Hong, Sun Ig

    2015-09-01

    Niobium oxide nanocrystals were successfully synthesized employing the green synthesis method. Phase formation, microstructure and compositional properties of 1, 4 and 7 days incubation treated samples after calcinations at 450 °C were examined using X-ray diffraction, Raman, photoluminescence (PL), infrared, X-ray photoelectron spectra and transmission electron microscopic characterizations. It was observed that phase formation of Nb2O5 nanocrystals was dependent upon the incubation period required to form stable metal oxides. The characteristic results clearly revealed that with increasing incubation and aging, the transformation of cubic, orthorhombic and monoclinic phases were observed. The uniform heating at room temperature (32 °C) and the ligation of niobium atoms due to higher phenolic constituents of utilized rambutan during aging processing plays a vital role in structural phase transitions in niobium oxide nanocrystals. The defects over a period of incubation and the intensities of the PL spectra changing over a period of aging were related to the amount of the defects induced by the phase transition.

  17. Spontaneous emission enhancement of colloidal perovskite nanocrystals

    Science.gov (United States)

    Yang, Zhili; Waks, Edo

    Halide perovskite semiconductors have emerged as prominent photovoltaic materials since their high conversion efficiency and promising light emitting materials in optoelectronics. In particular, easy-to-fabricated colloidal perovskite nanocrystals based on CsPbX3 quantum dots has been intensively investigated recently. Their luminescent wavelength could be tuned precisely by their chemical composition and size of growth. This opens new applications including light-emitting diodes, optical amplifiers and lasing since their promising performance as emitters. However, this potentially high-efficient emitter and gain material has not been fully investigated and realized in integrated photonic structures. Here we demonstrate Purcell enhancement effect of CsPbBr3 perovskite nanocrystals by coupling to an optimized photonic crystal nanobeam cavity as a first crucial step towards realization of integrated on-chip coherent light source with low energy consumption. We show clearly highly-enhanced photoluminescent spectrum and an averaged Purcell enhancement factor of 2.9 is achieved when they are coupled to nanobeam photonic crystal cavities compared to the ones on unpatterned surface in our lifetime measurement. Our success in enhancement of emission from CsPbX3 perovskite nanocrystals paves the way towards the realization of efficient light sources for integrated optoelectronic devices with low energy consumption.

  18. The coprecipitation of strontium with hydroxyapatite

    International Nuclear Information System (INIS)

    Fujino, Osamu

    1975-01-01

    The distribution behavior of the strontium ion between hydroxyapatite and the parent solution was investigated. The hydroxyapatite was formed by the extremely slow addition of diammonium hydrogenphosphate to solutions of calcium and strontium nitrate buffered with ethylenediamine at 80 0 C. The precipitate yielded a typical X-ray diffraction pattern of hydroxyapatite and had a composition in which the Ca/P molar ratio was 1.67 at pH 6.80. The strontium ion was coprecipitated in the apatite, obeying the Doerner and Hoskins logarithnmic distribution law. The distribution coefficient was scarcely affected by the strontium concentration on the pH value in the parent solution, and had a value of 0.26+-0.02 at 80 0 C. On the other hand, the apparent distribution coefficient was a little affected by such organic anions as acetate, citrate, lactate, glycinate, and glutamate ions. The lattice constants of the precipitates prepared in the research were measured in order to confirm the formation of the solid solutions. (auth.)

  19. Fabrication and electronic transport studies of single nanocrystal systems

    Energy Technology Data Exchange (ETDEWEB)

    Klein, David Louis [Univ. of California, Berkeley, CA (United States). Dept. of Physics

    1997-05-01

    Semiconductor and metallic nanocrystals exhibit interesting electronic transport behavior as a result of electrostatic and quantum mechanical confinement effects. These effects can be studied to learn about the nature of electronic states in these systems. This thesis describes several techniques for the electronic study of nanocrystals. The primary focus is the development of novel methods to attach leads to prefabricated nanocrystals. This is because, while nanocrystals can be readily synthesized from a variety of materials with excellent size control, means to make electrical contact to these nanocrystals are limited. The first approach that will be described uses scanning probe microscopy to first image and then electrically probe surfaces. It is found that electronic investigations of nanocrystals by this technique are complicated by tip-sample interactions and environmental factors such as salvation and capillary forces. Next, an atomic force microscope technique for the catalytic patterning of the surface of a self assembled monolayer is described. In principle, this nano-fabrication technique can be used to create electronic devices which are based upon complex arrangements of nanocrystals. Finally, the fabrication and electrical characterization of a nanocrystal-based single electron transistor is presented. This device is fabricated using a hybrid scheme which combines electron beam lithography and wet chemistry to bind single nanocrystals in tunneling contact between closely spaced metallic leads. In these devices, both Au and CdSe nanocrystals show Coulomb blockade effects with characteristic energies of several tens of meV. Additional structure is seen the transport behavior of CdSe nanocrystals as a result of its electronic structure.

  20. Acceleration of biomimetic mineralization to apply in bone regeneration

    International Nuclear Information System (INIS)

    Jayasuriya, A Champa; Shah, Chiragkumar; Ebraheim, Nabil A; Jayatissa, Ahalapitiya H

    2008-01-01

    The delivery of growth factors and therapeutic drugs into bone defects is a major clinical challenge. Biomimetically prepared bone-like mineral (BLM) containing a carbonated apatite layer can be used to deliver growth factors and drugs in a controlled manner. In the conventional biomimetic process, BLM can be deposited on the biodegradable polymer surfaces by soaking them in simulated body fluid (SBF) for 16 days or more. The aim of this study was to accelerate the biomimetic process of depositing BML in the polymer surfaces. We accelerated the deposition of mineral on 3D poly(lactic-co-glycolic acid) (PLGA) porous scaffolds to 36-48 h by modifying the biomimetic process parameters and applying surface treatments to PLGA scaffolds. The BLM was coated on scaffolds after surface treatments followed by incubation at 37 0 C in 15 ml of 5x SBF. We characterized the BLM created using the accelerated biomineralization process with wide angle x-ray diffraction (XRD), Fourier transform infrared (FTIR) microscopy, and scanning electron microscopy (SEM). The FTIR and XRD analyses of mineralized scaffolds show similarities between biomimetically prepared BLM, and bone bioapatite and carbonated apatite. We also found that the BLM layer on the surface of scaffolds was stable even after 21 days immersed in Tris buffered saline and cell culture media. This study suggests that BLM was stable for at least 3 weeks in both media, and therefore, BLM has a potential for use as a carrier for biological molecules for localized release applications as well as bone tissue engineering applications

  1. Extraordinary Interfacial Stitching between Single All-Inorganic Perovskite Nanocrystals

    NARCIS (Netherlands)

    Gomez, Leyre; Lin, Junhao; De Weerd, Chris; Poirier, Lucas; Boehme, Simon C.; Von Hauff, Elizabeth; Fujiwara, Yasufumi; Suenaga, Kazutomo; Gregorkiewicz, Tom

    2018-01-01

    All-inorganic cesium lead halide perovskite nanocrystals are extensively studied because of their outstanding optoelectronic properties. Being of a cubic shape and typically featuring a narrow size distribution, CsPbX3 (X = Cl, Br, and I) nanocrystals are the ideal starting material for the

  2. Synthesis and preservation of graphene-supported uranium dioxide nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Hanyu [Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556 (United States); Wang, Haitao [Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556 (United States); Department of Civil, Environmental, and Construction Engineering, Texas Tech University, 911 Boston Ave., Lubbock, TX 79409 (United States); Burns, Peter C. [Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556 (United States); Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); McNamara, Bruce K.; Buck, Edgar C. [Nuclear Chemistry & Engineering Group, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA 99352 (United States); Na, Chongzheng, E-mail: chongzheng.na@gmail.com [Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556 (United States); Department of Civil, Environmental, and Construction Engineering, Texas Tech University, 911 Boston Ave., Lubbock, TX 79409 (United States)

    2016-07-15

    Graphene-supported uranium dioxide (UO{sub 2}) nanocrystals are potentially important fuel materials. Here, we investigate the possibility of synthesizing graphene-supported UO{sub 2} nanocrystals in polar ethylene glycol compounds by the polyol reduction of uranyl acetylacetone under boiling reflux, thereby enabling the use of an inexpensive graphene precursor graphene oxide into a one-pot process. We show that triethylene glycol is the most suitable solvent with an appropriate reduction potential for producing nanometer-sized UO{sub 2} crystals compared to monoethylene glycol, diethylene glycol, and polyethylene glycol. Graphene-supported UO{sub 2} nanocrystals synthesized with triethylene glycol show evidence of heteroepitaxy, which can be beneficial for facilitating heat transfer in nuclear fuel particles. Furthermore, we show that graphene-supported UO{sub 2} nanocrystals synthesized by polyol reduction can be readily stored in alcohols, impeding oxidation from the prevalent oxygen in air. Together, these methods provide a facile approach for preparing and storing graphene-supported UO{sub 2} nanocrystals for further investigation and development under ambient conditions. - Highlights: • UO{sub 2} nanocrystals are synthesized using polyol reduction method. • Triethylene glycol is the best reducing agent for nano-sized UO{sub 2} crystals. • UO{sub 2} nanocrystals grow on graphene through heteroepitaxy. • Graphene-supported UO{sub 2} nanocrystals can be stored in alcohols to prevent oxidation.

  3. Characterization of Ge-nanocrystal films with photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Bostedt, C.; Buuren, T. van; Willey, T.M.; Nelson, A.J.; Franco, N.; Moeller, T.; Terminello, L.J.

    2003-01-01

    The Ge 3d core-levels of germanium nanocrystal films have been investigated by means of photoelectron spectroscopy. The experiments indicate bulk-like coordinated atoms in the nanocrystals and suggest structured disorder on the nanoparticle surface. The results underline the importance of the surface on the overall electronic structure of this class of nanostructured materials

  4. Group IV nanocrystals with ion-exchangeable surface ligands and methods of making the same

    Science.gov (United States)

    Wheeler, Lance M.; Nichols, Asa W.; Chernomordik, Boris D.; Anderson, Nicholas C.; Beard, Matthew C.; Neale, Nathan R.

    2018-01-09

    Methods are described that include reacting a starting nanocrystal that includes a starting nanocrystal core and a covalently bound surface species to create an ion-exchangeable (IE) nanocrystal that includes a surface charge and a first ion-exchangeable (IE) surface ligand ionically bound to the surface charge, where the starting nanocrystal core includes a group IV element.

  5. Fabrication and animal experiment of nanocomposites of hydroxyapatite collagen and polysaccharides

    Energy Technology Data Exchange (ETDEWEB)

    Ikoma, T.; Tanaka, J. [National Inst. for Research in Inorganic Materials and Technology Agency, Tsukuba, Ibaraki (Japan); CREST, Japan Science and Technology, Kawaguchi (Japan); Muneta, T. [Tokyo Medical and Dental Univ. (Japan). Dept. of Orhtopedic Surgery

    2001-07-01

    Four species of nanocomposites organized by hydroxyapatite (HAp), hyaluronic acid (HyA), chondroitin sulfate (ChS) and type II collagen (Col), i.e. HAp/HyA, HAp/ChS, HAp/HyA/Col and HAp/ChS/Col composites, were synthesized by coprecipitation methods. The composites could retain lots of water: 40%, 32%, 42% and 58% for the HAp/HyA, HAp/ChS, HAp/HyA/Col and HAp/ChS/Col composites, respectively. Transmission electron microscopy observations revealed that the HAp/HyA and HAp/ChS composites consisted of island-like aggregations whose sizes were 300 nm in length and 30 nm in width, and 150 nm in length and 30 nm in width, respectively. In the aggregations, there were many HAp nanocrystals of 20 nm in length, and their c-axes were aligned along the respective polymer molecules through a self-organization process. Animal tests showed that chondrocyte-like cells penetrated into the HAp/ChS/Col composites 4 weeks after implantation. It was shown that the HAp/ChS/Col composite has a potential for cartilage regeneration and the HAp/HyA/Col composite for bone regeneration. (orig.)

  6. Towards a Scalable, Biomimetic, Antibacterial Coating

    Science.gov (United States)

    Dickson, Mary Nora

    Corneal afflictions are the second leading cause of blindness worldwide. When a corneal transplant is unavailable or contraindicated, an artificial cornea device is the only chance to save sight. Bacterial or fungal biofilm build up on artificial cornea devices can lead to serious complications including the need for systemic antibiotic treatment and even explantation. As a result, much emphasis has been placed on anti-adhesion chemical coatings and antibiotic leeching coatings. These methods are not long-lasting, and microorganisms can eventually circumvent these measures. Thus, I have developed a surface topographical antimicrobial coating. Various surface structures including rough surfaces, superhydrophobic surfaces, and the natural surfaces of insects' wings and sharks' skin are promising anti-biofilm candidates, however none meet the criteria necessary for implementation on the surface of an artificial cornea device. In this thesis I: 1) developed scalable fabrication protocols for a library of biomimetic nanostructure polymer surfaces 2) assessed the potential these for poly(methyl methacrylate) nanopillars to kill or prevent formation of biofilm by E. coli bacteria and species of Pseudomonas and Staphylococcus bacteria and improved upon a proposed mechanism for the rupture of Gram-negative bacterial cell walls 3) developed a scalable, commercially viable method for producing antibacterial nanopillars on a curved, PMMA artificial cornea device and 4) developed scalable fabrication protocols for implantation of antibacterial nanopatterned surfaces on the surfaces of thermoplastic polyurethane materials, commonly used in catheter tubings. This project constitutes a first step towards fabrication of the first entirely PMMA artificial cornea device. The major finding of this work is that by precisely controlling the topography of a polymer surface at the nano-scale, we can kill adherent bacteria and prevent biofilm formation of certain pathogenic bacteria

  7. Fine structure study on low concentration zinc substituted hydroxyapatite nanoparticles

    International Nuclear Information System (INIS)

    Hu, Wei; Ma, Jun; Wang, Jianglin; Zhang, Shengmin

    2012-01-01

    The fine structure of zinc substituted hydroxyapatite was studied using experimental analysis and first-principles calculations. The synthetic hydroxyapatite nanoparticles containing low Zn concentration show rod-like morphology. The crystallite sizes and unit-cell volumes tended to decrease with the increased Zn concentration according to X-ray diffraction patterns. The Zn K-edge X-ray absorption spectra and fitting results suggest that the hydroxyapatite doped with 0.1 mole% zinc is different in the zinc coordination environments compared with that containing more zinc. The density function theory calculations were performed on zinc substituted hydroxyapatite. Two mechanisms included replacing calcium by zinc and inserting zinc along the hydroxyl column and were investigated, and the related substitution energies were calculated separately. It is found that the substitution energies are negative and lowest for inserting zinc between the two oxygen atoms along the hydroxyl column (c-axis). Combined with the spectral analysis, it is suggested that the inserting mechanism is favored for low concentration zinc substituted hydroxyapatite. Highlights: ► We investigate the fine structure of hydroxyapatite with low content of Zn. ► XANES spectra are similar but a little different at low zinc content. ► Zinc ions influence hydroxyapatite crystal formation and lattice parameters. ► Formation energies are calculated according to plane-wave density function theory. ► Low content of zinc prefers to locate at hydroxyl column in hydroxyapatite lattice.

  8. Electrophoretic deposition of composite hydroxyapatite-chitosan coatings

    International Nuclear Information System (INIS)

    Pang Xin; Zhitomirsky, Igor

    2007-01-01

    Cathodic electrophoretic deposition has been utilized for the fabrication of composite hydroxyapatite-chitosan coatings on 316L stainless steel substrates. The addition of chitosan to the hydroxyapatite suspensions promoted the electrophoretic deposition of the hydroxyapatite nanoparticles and resulted in the formation of composite coatings. The obtained coatings were investigated by X-ray diffraction, thermogravimetric and differential thermal analysis, scanning and transmission electron microscopy, potentiodynamic polarization measurements, and electrochemical impedance spectroscopy. It was shown that the deposit composition can be changed by a variation of the chitosan or hydroxyapatite concentration in the solutions. Experimental conditions were developed for the fabrication of hydroxyapatite-chitosan nanocomposites containing 40.9-89.8 wt.% hydroxyapatite. The method enabled the formation of adherent and uniform coatings of thicknesses up to 60 μm. X-ray studies revealed that the preferred orientation of the hydroxyapatite nanoparticles in the chitosan matrix increases with decreasing hydroxyapatite content in the composite coatings. The obtained coatings provided the corrosion protection for the 316L stainless steel substrates

  9. Hydroxyapatite does not improve the outcome of a bipolar hemiarthroplasty.

    NARCIS (Netherlands)

    Meijerink, H.J.; Gardeniers, J.W.M.; Buma, P.; Lemmens, J.A.M.; Schreurs, B.W.

    2004-01-01

    In a one-surgeon study the clinical and radiographic results of 30 cementless bipolar hip prostheses in 24 patients younger than 55 years were evaluated. Eleven noncoated prostheses (Noncoated Group) and 19 hydroxyapatite-coated prostheses (Hydroxyapatite Group) were compared after a mean followup

  10. Development of hydroxyapatite bone cement for controlled drug ...

    Indian Academy of Sciences (India)

    The purpose of this work was to study the preparation and characterization of drug–hydroxyapatite cement. The hydroxyapatite (HA) cement has been synthesized by using tricalcium phosphate, calcium carbonate and dicalcium phosphate anhydrous with sodium hydrogen phosphate as liquid phase. The effect of added ...

  11. In-situ deposition of hydroxyapatite on graphene nanosheets

    OpenAIRE

    Neelgund, Gururaj M.; Oki, Aderemi; Luo, Zhiping

    2013-01-01

    Graphene nanosheets were effectively functionalized by in-situ deposition of hydroxyaptite through a facile chemical precipitation method. Prior to grafting of hydroxyapatite, chemically modified graphene nanosheets were obtained by the reduction of graphene oxide in presence of ethylenediamine. The resulting hydroxyapatite functionalized graphene nanosheets were characterized by attenuated total reflection IR spectroscopy, X-ray diffraction, field emission scanning electron microscopy, trans...

  12. Synthesis and Characterization of Hydroxyapatite Powder by Wet Precipitation Method

    Science.gov (United States)

    Cahyaningrum, S. E.; Herdyastuty, N.; Devina, B.; Supangat, D.

    2018-01-01

    Hydroxyapatite is main inorganic component of the bone with formula Ca10(PO4)6(OH)2. Hydroxyapatite can be used as substituted bone biomaterial because biocompatible, non toxic, and osteoconductive. In this study, hydroxyapatite is synthesized using wet precipitation method from egg shell. The product was sintered at different temperatures of 800°C to 1000°C to improve its crystallinity. The hydroxyapatite was characterized by X-ray analysis, Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) to reveal its phase content, morphology and types of bond present within it. The analytical results showed hydroxyapatite had range in crystallinity from 85.527 to 98.753%. The analytical functional groups showed that presence of functional groups such as OH, (PO4)3 2-, and CO3 2- that indicated as hydroxyapatite. The result of characterization SEM indicated that hydroxyapatite without sintering and HAp sintering at 800 °C were irregular shape without pore. The best hydroxyapatite with temperature sintering at 900 °C showed oval shaped with pores without agglomerated.

  13. In Situ Generation of Cellulose Nanocrystals in Polycaprolactone Nanofibers: Effects on Crystallinity, Mechanical Strength, Biocompatibility, and Biomimetic Mineralization.

    Science.gov (United States)

    Joshi, Mahesh Kumar; Tiwari, Arjun Prasad; Pant, Hem Raj; Shrestha, Bishnu Kumar; Kim, Han Joo; Park, Chan Hee; Kim, Cheol Sang

    2015-09-09

    Post-electrospinning treatment is a facile process to improve the properties of electrospun nanofibers for various applications. This technique is commonly used when direct electrospinning is not a suitable option to fabricate a nonwoven membrane of the desired polymer in a preferred morphology. In this study, a representative natural-synthetic hybrid of cellulose acetate (CA) and polycaprolactone (PCL) in different ratios was fabricated using an electrospinning process, and CA in the hybrid fiber was transformed into cellulose (CL) by post-electrospinning treatment via alkaline saponification. Scanning electron microscopy was employed to study the effects of polymer composition and subsequent saponification on the morphology of the nanofibers. Increasing the PCL content in the PCL/CA blend solution caused a gradual decrease in viscosity, resulting in smoother and more uniform fibers. The saponification of fibers lead to pronounced changes in the physicochemical properties. The crystallinity of the PCL in the composite fiber was varied according to the composition of the component polymers. The water contact angle was considerably decreased (from 124° to less than 20°), and the mechanical properties were greatly enhanced (Young's Modulus was improved by ≈20-30 fold, tensile strength by 3-4 fold, and tensile stress by ≈2-4 fold) compared to those of PCL and PCL/CA membranes. Regeneration of cellulose chains in the nanofibers increased the number of hydroxyl groups, which increased the hydrogen bonding, thereby improving the mechanical properties and wettability of the composite nanofibers. The improved wettability and presence of surface functional groups enhanced the ability to nucleate bioactive calcium phosphate crystals throughout the matrix when exposed to a simulated body fluid solution. Experimental results of cell viability assay, confocal microscopy, and scanning electron microscopy imaging showed that the fabricated nanofibrous membranes have excellent ability for MC3T3-E1 cell proliferation and growth. Given the versatility and widespread use of cellulose-synthetic hybrid systems in the construction of tissue-engineered scaffolds, this work provides a novel strategy to fabricate the biopolymer-based materials for applications in tissue engineering and regenerative medicine.

  14. Microstructural and surface modifications and hydroxyapatite coating of Ti-6Al-4V triply periodic minimal surface lattices fabricated by selective laser melting.

    Science.gov (United States)

    Yan, Chunze; Hao, Liang; Hussein, Ahmed; Wei, Qingsong; Shi, Yusheng

    2017-06-01

    Ti-6Al-4V Gyroid triply periodic minimal surface (TPMS) lattices were manufactured by selective laser melting (SLM). The as-built Ti-6Al-4V lattices exhibit an out-of-equilibrium microstructure with very fine α' martensitic laths. When subjected to the heat treatment of 1050°C for 4h followed by furnace cooling, the lattices show a homogenous and equilibrium lamellar α+β microstructure with less dislocation and crystallographic defects compared with the as-built α' martensite. The as-built lattices present very rough strut surfaces bonded with plenty of partially melted metal particles. The sand blasting nearly removed all the bonded metal particles, but created many tiny cracks. The HCl etching eliminated these tiny cracks, and subsequent NaOH etching resulted in many small and shallow micro-pits and develops a sodium titanate hydrogel layer on the surfaces of the lattices. When soaked in simulated body fluid (SBF), the Ti-6Al-4V TPMS lattices were covered with a compact and homogeneous biomimetic hydroxyapatite (HA) layer. This work proposes a new method for making Ti-6Al-4V TPMS lattices with a homogenous and equilibrium microstructure and biomimetic HA coating, which show both tough and bioactive characteristics and can be promising materials usable as bone substitutes. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Photoluminescence from Si nanocrystals in silica: The effect of hydrogen

    International Nuclear Information System (INIS)

    Cheylan, S.; Elliman, R.G.

    2001-01-01

    The effect of H passivation on the PL emission of Si nanocrystals produced in silica by ion-implantion and annealing is shown to depend on the implant fluence. At low fluences, where the nanocrystals are small, passivation causes an enhancement of the emission intensity that is uniform over the full spectral range and therefore appears to be independent of nanocrystal size. For higher fluences, where the average size and size distribution of the nanocrystals are larger, the enhancement occurs preferentially at longer wavelengths, giving rise to a red-shift in the emission spectra. Both the enhancement and the red-shift increase monotonically with increasing fluence. These data are shown to be consistent with a model in which the probability to contain a non-radiative defect increases with nanocrystal size

  16. Isolating and moving single atoms using silicon nanocrystals

    Science.gov (United States)

    Carroll, Malcolm S.

    2010-09-07

    A method is disclosed for isolating single atoms of an atomic species of interest by locating the atoms within silicon nanocrystals. This can be done by implanting, on the average, a single atom of the atomic species of interest into each nanocrystal, and then measuring an electrical charge distribution on the nanocrystals with scanning capacitance microscopy (SCM) or electrostatic force microscopy (EFM) to identify and select those nanocrystals having exactly one atom of the atomic species of interest therein. The nanocrystals with the single atom of the atomic species of interest therein can be sorted and moved using an atomic force microscope (AFM) tip. The method is useful for forming nanoscale electronic and optical devices including quantum computers and single-photon light sources.

  17. Facile synthesis of water-soluble curcumin nanocrystals

    Directory of Open Access Journals (Sweden)

    Marković Zoran M.

    2015-01-01

    Full Text Available In this paper, facile synthesis of water soluble curcumin nanocrystals is reported. Solvent exchange method was applied to synthesize curcumin nanocrystals. Different techniques were used to characterize the structural and photophysical properties of curcumin nanocrystals. We found that nanocurcumin prepared by this method had good chemical and physical stability, could be stored in the powder form at room temperature, and was freely dispersible in water. It was established that the size of curcumin nanocrystals was varied in the range of 20-500 nm. Fourier transform infrared spectroscopy and UV-Vis analyses showed the presence of tetrahydrofuran inside the curcumin nanocrystals. Also, it was found that nanocurcumin emitted photoluminescencewith yellow-green colour. [Projekat Ministarstva nauke Republike Srbije, br. 172003

  18. Plasmonic light-sensitive skins of nanocrystal monolayers

    Science.gov (United States)

    Akhavan, Shahab; Gungor, Kivanc; Mutlugun, Evren; Demir, Hilmi Volkan

    2013-04-01

    We report plasmonically coupled light-sensitive skins of nanocrystal monolayers that exhibit sensitivity enhancement and spectral range extension with plasmonic nanostructures embedded in their photosensitive nanocrystal platforms. The deposited plasmonic silver nanoparticles of the device increase the optical absorption of a CdTe nanocrystal monolayer incorporated in the device. Controlled separation of these metallic nanoparticles in the vicinity of semiconductor nanocrystals enables optimization of the photovoltage buildup in the proposed nanostructure platform. The enhancement factor was found to depend on the excitation wavelength. We observed broadband sensitivity improvement (across 400-650 nm), with a 2.6-fold enhancement factor around the localized plasmon resonance peak. The simulation results were found to agree well with the experimental data. Such plasmonically enhanced nanocrystal skins hold great promise for large-area UV/visible sensing applications.

  19. Gallium-containing hydroxyapatite for potential use in orthopedics

    International Nuclear Information System (INIS)

    Melnikov, P.; Teixeira, A.R.; Malzac, A.; Coelho, M. de B.

    2009-01-01

    A novel material that may be recommended for grafts and implants stimulating bone growth has been obtained by introducing gallium ions (up to 11.0 mass%) into crystalline lattice of hydroxyapatite. The doping was carried out using gallium nitrate and sodium gallate solutions. In both cases, lattice parameters of gallium-doped hydroxyapatite are identical to those of pure synthetic hydroxyapatite. Gallium does not replace calcium as a result of heterovalent substitution and consequently produces no distortions in the framework of hydroxyapatite matrix. It remains strongly fixed in the form of solid solution of intercalation. According to scanning electron microscopy images gallium insertion does not cause any morphological alterations in hydroxyapatite structure and the product developed meets physico-chemical criteria for biomaterial to be employed in orthopedic practice and local handling of traumatic injuries. Its future usage opens the opportunity to enhance osteosynthesis and calcium retention in loco.

  20. Study on carbonated hydroxyapatite as a thermoluminescence dosimeter

    International Nuclear Information System (INIS)

    Shafaei, M.; Sardari, D.; Ziaie, F.; Larijani, M.M.

    2015-01-01

    In this study, carbonated hydroxyapatite nanoparticles were used for thermoluminescence dosimetry. The nano-structure carbonated hydroxyapatite synthesized via hydrolysis of CaHPO 4 and CaCO 3 . The obtained nano powders were characterized by XRD technique and FTIR spectroscopy system. The carbonated hydroxyapatite samples were irradiated at different doses using 60 Co gamma rays, and were subjected to thermoluminescence measurement system, consequently. The TL glow curve exhibited two distinguishable peaks centered at around of 165 C and 310 C. The TL response of carbonated hydroxyapatite samples as a function of absorbed dose was linear in the range of 25-1000 Gy. Other dosimetric features of the carbonated hydroxyapatite nanoparticles including fading and reproducibility were also investigated.

  1. Synthesis of nanocrystalline hydroxyapatite by using precipitation method

    International Nuclear Information System (INIS)

    Mobasherpour, I.; Heshajin, M. Soulati; Kazemzadeh, A.; Zakeri, M.

    2007-01-01

    In this investigation, hydroxyapatite powder has been synthesized from the calcium nitrate hydrated and di-ammonium hydrogen phosphate solution by precipitation method and heat treatment of hydroxyapatite powders. In order to study the structural evolution, the Fourier transform infrared spectroscopy (FTIR), the X-ray diffraction (XRD) and simultaneous thermal analysis (STA) were used. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to estimate the particle size of the powder and observe the morphology and agglomeration state of the powder. Results show that hydroxyapatite nanocrystalline can successfully be produced by precipitation technique from raw materials. Hydroxyapatite grain gradually increased in size when temperature increased from 100 to 1200 o C, and the hydroxyapatite hexagonal-dipyramidal phase was not transformed to the other calcium phosphates phases up to 1200 o C

  2. Z-Contrast STEM Imaging and EELS of CdSe Nanocrystals: Towards the Analysis of Individual Nanocrystal Surfaces

    International Nuclear Information System (INIS)

    Erwin, M.; Kadavanich, A.V.; Kippeny, T.; Pennycook, S.J.; Rosenthal, S.J.

    1999-01-01

    We have applied Atomic Number Contract Scanning Transmission Electron Microscopy (Z-Contrast STEM) and STEM/EELS (Electron Energy Loss Spectroscopy) towards the study of colloidal CdSe semiconductor nanocrystals embedded in MEH-PPV polymer films. Unlike the case of conventional phase-contrast High Resolution TEM, Z-Contrast images are direct projections of the atomic structure. Hence they can be interpreted without the need for sophisticated image simulation and the image intensity is a direct measure of the thickness of a nanocrystal. Our thickness measurements are in agreement with the predicted faceted shape of these nanocrystals. Our unique 1.3A resolution STEM has successfully resolve3d the sublattice structure of these CdSe nanocrystals. In [010] projection (the polar axis in the image plane) we can distinguish Se atom columns from Cd columns. Consequently we can study the effects of lattice polarity on the nanocrystal morphology. Furthermore, since the STEM technique does not rely on diffraction, it is superbly suited to the study of non-periodic detail, such as the surface structure of the nanocrystals. EELS measurements on individual nanocrystals indicate a significant amount (equivalet to 0.5-1 surface monolayers) of oxygen on the nanocrystals, despite processing in an inert atmosphere. Spatially resolved measurements at 7A resolution suggest a surface oxide layer. However, the uncertainty in the measurement precludes definitive assignment at this time. The source of the oxygen is under investigation as well

  3. Biomimetic nanoclay scaffolds for bone tissue engineering

    Science.gov (United States)

    Ambre, Avinash Harishchandra

    Tissue engineering offers a significant potential alternative to conventional methods for rectifying tissue defects by evoking natural regeneration process via interactions between cells and 3D porous scaffolds. Imparting adequate mechanical properties to biodegradable scaffolds for bone tissue engineering is an important challenge and extends from molecular to macroscale. This work focuses on the use of sodium montmorillonite (Na-MMT) to design polymer composite scaffolds having enhanced mechanical properties along with multiple interdependent properties. Materials design beginning at the molecular level was used in which Na-MMT clay was modified with three different unnatural amino acids and further characterized using Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD). Based on improved bicompatibility with human osteoblasts (bone cells) and intermediate increase in d-spacing of MMT clay (shown by XRD), 5-aminovaleric acid modified clay was further used to prepare biopolymer (chitosan-polygalacturonic acid complex) scaffolds. Osteoblast proliferation in biopolymer scaffolds containing 5-aminovaleric acid modified clay was similar to biopolymer scaffolds containing hydroxyapatite (HAP). A novel process based on biomineralization in bone was designed to prepare 5-aminovaleric acid modified clay capable of imparting multiple properties to the scaffolds. Bone-like apatite was mineralized in modified clay and a novel nanoclay-HAP hybrid (in situ HAPclay) was obtained. FTIR spectroscopy indicated a molecular level organic-inorganic association between the intercalated 5-aminovaleric acid and mineralized HAP. Osteoblasts formed clusters on biopolymer composite films prepared with different weight percent compositions of in situ HAPclay. Human MSCs formed mineralized nodules on composite films and mineralized extracellular matrix (ECM) in composite scaffolds without the use of osteogenic supplements. Polycaprolactone (PCL), a synthetic polymer, was

  4. Effects of hydroxyapatite nanostructure on channel surface of porcine acellular dermal matrix scaffold on cell viability and osteogenic differentiation of human periodontal ligament stem cells

    Directory of Open Access Journals (Sweden)

    Ge S

    2013-05-01

    Full Text Available Shaohua Ge,1 Ning Zhao,1 Lu Wang,1 Hong Liu,2 Pishan Yang11Shandong Provincial Key Laboratory of Oral Biomedicine, Department of Periodontology, Shandong University; 2State Key Laboratory of Crystal Materials, Center of Bio and Micro/Nano Functional Materials, Shandong University, Jinan, People's Republic of ChinaAbstract: A new nanostructured hydroxyapatite-coated porcine acellular dermal matrix (HAp-PADM was fabricated by a biomimetic mineralization method. Human periodontal ligament stem cells were seeded on HAp-PADM and the effects of this scaffold on cell shape, cytoskeleton organization, cell viability, and osteogenic differentiation were examined. Periodontal ligament stem cells cultured on HAp-PADM exhibited different cell shape when compared with those on pure PADM. Moreover, HAp-PADM promoted cell viability and alkaline phosphatase activity significantly. Based on quantitative real-time polymerase chain reaction, the expression of bone-related markers runt-related transcription factor 2 (Runx2, osteopontin (OPN, and osteocalcin (OCN upregulated in the HAp-PADM scaffold. The enhancement of osteogenic differentiation of periodontal ligament stem cells on the HAp-PADM scaffold was proposed based on the research results. The results of this study highlight the micro-nano, two-level, three-dimensional HAp-PADM composite as a promising scaffold for periodontal tissue engineering.Keywords: hydroxyapatite, scaffold, nanostructure, proliferation, differentiation, tissue engineering

  5. Synthesis and Characterization of Colloidal Metal and Photovoltaic Semiconductor Nanocrystals

    KAUST Repository

    Abulikemu, Mutalifu

    2014-11-05

    Metal and semiconducting nanocrystals have received a great deal of attention from fundamental scientists and application-oriented researchers due to their physical and chemical properties, which differ from those of bulk materials. Nanocrystals are essential building blocks in the development of nanostructured devices for energy conversion. Colloidal metals and metal chalcogenides have been developed for use as nanocrystal inks to produce efficient solar cells with lower costs. All high-performing photovoltaic nanocrystals contain toxic elements, such as Pb, or scarce elements, such as In; thus, the production of solution-processable nanocrystals from earth-abundant materials using environmentally benign synthesis and processing methods has become a major challenge for the inorganic semiconductor-based solar field. This dissertation, divided into two parts, addresses several aspects of these emerging challenges. The first portion of the thesis describes the synthesis and characterization of nanocrystals of antimony sulfide, which is composed of non-scarce and non-toxic elements, and examines their performance in photovoltaic devices. The effect of various synthetic parameters on the final morphology is explored. The structural, optical and morphological properties of the nanocrystals were investigated, and Sb2S3 nanocrystal-based solid-state semiconductor-sensitized solar cells were fabricated using different deposition processes. We achieved promising power conversion efficiencies of 1.48%. The second part of the thesis demonstrates a novel method for the in situ synthesis and patterning of nanocrystals via reactive inkjet printing. The use of low-cost manufacturing approaches for the synthesis of nanocrystals is critical for many applications, including photonics and electronics. In this work, a simple, low-cost method for the synthesis of nanocrystals with minimum size variation and waste using reactive inkjet printing is introduced. As a proof of concept, the

  6. Formation of noble metal nanocrystals in the presence of biomolecules

    Science.gov (United States)

    Burt, Justin Lockheart

    One of the most promising, yet least studied routes for producing biocompatible nanostructures involves synthesis in the presence of biomolecules. I hypothesized that globular proteins could provide a suitable framework to regulate the formation of noble metal nanocrystals. As proof of concept, I designed two novel synthesis protocols utilizing bovine serum albumin (BSA) protein to regulate the formation of gold nanocrystals. In the first case, the standard protocol for polyol reduction was modified by replacing ethylene glycol with glycerin, replacing synthetic polymers with BSA as protecting agent, and decreasing the reaction temperature. In the second case, the Brust-Schiffrin two-phase reduction was modified by replacing alkylthiols with BSA as protecting agent, which facilitated a strictly aqueous phase synthesis. Due to superior product yield and rapid reduction at room temperature, the aqueous protocol became the foundation for subsequent studies. I extended this approach to produce well-dispersed ˜2nm silver, gold, and platinum nanocrystals. Having demonstrated the feasibility of BSA-functionalized nanocrystals, some potential uses were explored. BSA-functionalized silver nanocrystals were employed in a broader study on the interaction of silver nanocrystals with HIV. BSA-functionalized gold nanocrystals were utilized for in vivo dosage of a contrast enhancing agent to bacteria. BSA-functionalized platinum nanocrystals were studied as hydrogenation catalysts. Since many intriguing uses for protein-functionalized nanocrystals involve incorporation into biosystems, I sought to enhance biocompatibility by using ascorbic acid as reducing agent. Initial experiments revealed elongated and branched nanocrystals. Such structures were not observed in previous synthesis protocols with BSA, so I hypothesized ascorbic acid was driving their formation. To test my assertion, I reduced ionic gold in an aqueous solution of ascorbic acid, thereby discovering a new method

  7. Cytotoxicity of nano-hydroxyapatite on human-derived oral epithelium cell line: an in vitro study

    OpenAIRE

    Farid Abassi; Mandana Sattari; Noushin Jalayer Naderi; Marzie Sorooshzadeh

    2016-01-01

    Background: Hydroxyapatite nanoparticles have a more surface contact and solubility than conventional hydroxyapatite. Hydroxynanoparticles enhances the biological and mechanical properties of new regenerated tissues. The hydroxyapatite nanoparticles have received attention as a new and effective osseous graft for using as scaffolds in bone regeneration. The reports on hydroxyapatite nanoparticles biocompatibility are controversial. It has been shown that hydroxyapatite nanoparticles induces i...

  8. Semiconductor nanocrystals for novel optical applications

    Science.gov (United States)

    Moon, Jong-Sik

    Inspired by the promise of enhanced spectral response, photorefractive polymeric composites photosensitized with semiconductor nanocrystals have emerged as an important class of materials. Here, we report on the photosensitization of photorefractive polymeric composites at visible wavelengths through the inclusion of narrow band-gap semiconductor nanocrystals composed of PbS. Through this approach, internal diffraction efficiencies in excess of 82%, two-beam-coupling gain coefficients in excess of 211 cm-1, and response times 34 ms have been observed, representing some of the best figures-of-merit reported on this class of materials. In addition to providing efficient photosensitization, however, extensive studies of these hybrid composites have indicated that the inclusion of nanocrystals also provides an enhancement in the charge-carrier mobility and subsequent reduction in the photorefractive response time. Through this approach with PbS as charge-carrier, unprecedented response times of 399 micros were observed, opening the door for video and other high-speed applications. It is further demonstrated that this improvement in response time occurs with little sacrifice in photorefractive efficiency and with internal diffraction efficiencies of 72% and two- beam-coupling gain coefficients of 500 cm-1 being measured. A thorough analysis of the experimental data is presented, supporting the hypothesized mechanism of the enhanced charge mobility without the accompaniment of superfluous traps. Finally, water soluble InP/ZnS and CdSe/ZnS quantum dots interacted with CPP and Herceptin to apply them as a bio-maker. Both of quantum dots showed the excellent potential for use in biomedical imaging and drug delivery applications. It is anticipated that these approaches can play a significant role in the eventual commercialization of these classes of materials.

  9. Silicon Nanocrystal Synthesis in Microplasma Reactor

    Science.gov (United States)

    Nozaki, Tomohiro; Sasaki, Kenji; Ogino, Tomohisa; Asahi, Daisuke; Okazaki, Ken

    Nanocrystalline silicon particles with grains smaller than 5 nm are widely recognized as a key material in optoelectronic devices, lithium battery electrodes, and bio-medical labels. Another important characteristic is that silicon is an environmentally safe material that is used in numerous silicon technologies. To date, several synthesis methods such as sputtering, laser ablation, and plasma-enhanced chemical vapor deposition (PECVD) based on low-pressure silane chemistry (SiH4) have been developed for precise control of size and density distributions of silicon nanocrystals. In this study, we explore the possibility of microplasma technologies for efficient production of mono-dispersed nanocrystalline silicon particles on a micrometer-scale, continuous-flow plasma reactor operated at atmospheric pressure. Mixtures of argon, hydrogen, and silicon tetrachloride were activated using a very-high-frequency (144 MHz) power source in a capillary glass tube with volume of less than 1 μl. Fundamental plasma parameters of the microplasma were characterized using optical emission spectroscopy, which respectively indicated electron density of 1015 cm-3, argon excitation temperature of 5000 K, and rotational temperature of 1500 K. Such high-density non-thermal reactive plasma can decompose silicon tetrachloride into atomic silicon to produce supersaturated silicon vapor, followed by gas-phase nucleation via three-body collision: particle synthesis in high-density plasma media is beneficial for promoting nucleation processes. In addition, further growth of silicon nuclei can be terminated in a short-residence-time reactor. Micro-Raman scattering spectra showed that as-deposited particles are mostly amorphous silicon with a small fraction of silicon nanocrystals. Transmission electron micrography confirmed individual 3-15 nm silicon nanocrystals. Although particles were not mono-dispersed, they were well separated and not coagulated.

  10. Synthesis of Silicon Nanocrystals in Microplasma Reactor

    Science.gov (United States)

    Nozaki, Tomohiro; Sasaki, Kenji; Ogino, Tomohisa; Asahi, Daisuke; Okazaki, Ken

    Nanocrystalline silicon particles with a grain size of at least less than 10 nm are widely recognized as one of the key materials in optoelectronic devices, electrodes of lithium battery, bio-medical labels. There is also important character that silicon is safe material to the environment and easily gets involved in existing silicon technologies. To date, several synthesis methods such as sputtering, laser ablation, and plasma enhanced chemical vapor deposition (PECVD) based on low-pressure silane chemistry (SiH4) have been developed for precise control of size and density distributions of silicon nanocrystals. We explore the possibility of microplasma technologies for the efficient production of mono-dispersed nanocrystalline silicon particles in a micrometer-scale, continuous-flow plasma reactor operated at atmospheric pressure. Mixtures of argon, hydrogen, and silicon tetrachloride were activated using very high frequency (VHF = 144 MHz) power source in a capillary glass tube with a volume of less than 1 μ-liter. Fundamental plasma parameters of VHF capacitively coupled microplasma were characterized by optical emission spectroscopy, showing electron density of approximately 1015 cm-3 and rotational temperature of 1500 K, respectively. Such high-density non-thermal reactive plasma has a capability of decomposing silicon tetrachloride into atomic silicon to produce supersaturated atomic silicon vapor, followed by gas phase nucleation via three-body collision. The particle synthesis in high-density plasma media is beneficial for promoting nucleation process. In addition, further growth of silicon nuclei was able to be favorably terminated in a short-residence time reactor. Micro Raman scattering spectrum showed that as-deposited particles were mostly amorphous silicon with small fraction of silicon nanocrystals. Transmission electron micrograph confirmed individual silicon nanocrystals of 3-15 nm size. Although those particles were not mono-dispersed, they were

  11. Iron inhibits hydroxyapatite crystal growth in vitro.

    Science.gov (United States)

    Guggenbuhl, Pascal; Filmon, Robert; Mabilleau, Guillaume; Baslé, Michel F; Chappard, Daniel

    2008-07-01

    Hemochromatosis is a known cause of osteoporosis in which the pathophysiology of bone loss is largely unknown and the role of iron remains questionable. We have investigated the effects of iron on the growth of hydroxyapatite crystals in vitro on carboxymethylated poly(2-hydroxyethyl methacrylate) pellets. This noncellular and enzyme-independent model mimics the calcification of woven bone (composed of calcospherites made of hydroxyapatite crystals). Polymer pellets were incubated with body fluid containing iron at increasing concentrations (20, 40, 60 micromol/L). Hydroxyapatite growth was studied by chemical analysis, scanning electron microscopy, and Raman microscopy. When incubated in body fluid containing iron, significant differences were observed with control pellets. Iron was detected at a concentration of 5.41- to 7.16-fold that of controls. In pellets incubated with iron, there was a approximately 3- to 4-fold decrease of Ca and P and a approximately 1.3- to 1.4-fold increase in the Ca/P ratio. There was no significant difference among the iron groups of pellets, but a trend to a decrease of Ca with the increase of iron concentration was noted. Calcospherite diameters were significantly lower on pellets incubated with iron. Raman microspectroscopy showed a decrease in crystallinity (measured by the full width of the half height of the 960 Deltacm(-1) band) with a significant increase in carbonate substitution (measured by the intensity ratio of 1071 to 960 Deltacm(-1) band). Energy dispersive x-ray analysis identified iron in the calcospherites. In vitro, iron is capable to inhibit bone crystal growth with significant changes in crystallinity and carbonate substitution.

  12. Solvothermal crystallization of nanocrystals of metal oxides

    International Nuclear Information System (INIS)

    Furukawa, S; Amino, H; Iwamoto, S; Inoue, M

    2008-01-01

    Solvothermal crystallization of the hydroxide gels obtained by hydrolysis of alkoxides (Zr, Ta, Nb, ln, Sn, Ti and Al) was examined. Nanocrystals having high surface areas (S BET > 170 m 2 g -1 ) were obtained except for the product derived from indium isopropoxide. The effect of water in organic solvent upon the crystallinity of the product was investigated. The increase in the activity of water by using high concentration of alkoxide or intentional addition of water to the solvothermal medium led to crystal growth of the products. In contrast, decrease in activity of water by adding ethylene glycol before solvothermal treatment caused a decrease in crystallinity of the product

  13. Flame synthesis of zinc oxide nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Merchan-Merchan, Wilson, E-mail: wmerchan-merchan@ou.edu [School of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019 (United States); Farahani, Moien Farmahini [School of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019 (United States)

    2013-02-01

    Highlights: Black-Right-Pointing-Pointer We report a single-step flame method for the synthesis of Zn oxide nanocrystals. Black-Right-Pointing-Pointer Diverse flame positions lead to a variation of Zn oxide nanocrystal growth. Black-Right-Pointing-Pointer The synthesized crystals have polyhedral, pipet- and needle-like shape. Black-Right-Pointing-Pointer High length-to-diameter aspect-ratio crystals appear in a higher temperature flame. Black-Right-Pointing-Pointer The crystal growth mechanism corresponds to vapor-to-solid conversion. - Abstract: Distinctive zinc oxide (ZnO) nanocrystals were synthesized on the surface of Zn probes using a counter-flow flame medium formed by methane/acetylene and oxygen-enriched air streams. The source material, a zinc wire with a purity of {approx}99.99% and diameter of 1 mm, was introduced through a sleeve into the oxygen rich region of the flame. The position of the probe/sleeve was varied within the flame medium resulting in growth variation of ZnO nanocrystals on the surface of the probe. The shape and structural parameters of the grown crystals strongly depend on the flame position. Structural variations of the synthesized crystals include single-crystalline ZnO nanorods and microprisms (ZMPs) (the ZMPs have less than a few micrometers in length and several hundred nanometers in cross section) with a large number of facets and complex axial symmetry with a nanorod protruding from their tips. The protruding rods are less than 100 nm in diameter and lengths are less than 1 {mu}m. The protruding nanorods can be elongated several times by increasing the residence time of the probe/sleeve inside the oxygen-rich flame or by varying the flame position. At different flame heights, nanorods having higher length-to-diameter aspect-ratio can be synthesized. A lattice spacing of {approx}0.26 nm was measured for the synthesized nanorods, which can be closely correlated with the (0 0 2) interplanar spacing of hexagonal ZnO (Wurtzite) cells

  14. Structure and Magnetic Properties of Lanthanide Nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Dickerson, James Henry [Vanderbilt Univ., Nashville, TN (United States)

    2014-06-01

    We have had considerable success on this project, particularly in the understanding of the relationship between nanostructure and magnetic properties in lanthanide nanocrystals. We also have successfully facilitated the doctoral degrees of Dr. Suseela Somarajan, in the Department of Physics and Astronomy, and Dr. Melissa Harrison, in the Materials Science Program. The following passages summarize the various accomplishments that were featured in 9 publications that were generated based on support from this grant. We thank the Department of Energy for their generous support of our research efforts in this area of materials science, magnetism, and electron microscopy.

  15. Solvothermal crystallization of nanocrystals of metal oxides

    Science.gov (United States)

    Furukawa, S.; Amino, H.; Iwamoto, S.; Inoue, M.

    2008-07-01

    Solvothermal crystallization of the hydroxide gels obtained by hydrolysis of alkoxides (Zr, Ta, Nb, ln, Sn, Ti and Al) was examined. Nanocrystals having high surface areas (SBET > 170 m2 g-1) were obtained except for the product derived from indium isopropoxide. The effect of water in organic solvent upon the crystallinity of the product was investigated. The increase in the activity of water by using high concentration of alkoxide or intentional addition of water to the solvothermal medium led to crystal growth of the products. In contrast, decrease in activity of water by adding ethylene glycol before solvothermal treatment caused a decrease in crystallinity of the product.

  16. Synthesis of hydroxyapatite from biogenic wastes

    Directory of Open Access Journals (Sweden)

    Teerawat Laonapakul

    2015-09-01

    Full Text Available Hydroxyapatite (HAp is a major component of human bone, teeth and hard tissue. It is one of only a few bioactive materials. Since HAp is the most widely used ceramic biomaterial, various techniques have been developed to synthesize HAp. In recent years, the use of natural biogenic structures and materials for medical proposes has been motivated by limitations in producing synthetic materials. This article mainly focuses on the use of biogenic wastes to prepare HAp. These include bio-wastes, marine corals, eggshells, seashells and bio-membranes. In the present review, useful information about HAp preparation methodologies has been summarized for further research and development.

  17. Fabricating hydroxyapatite nanorods using a biomacromolecule template

    International Nuclear Information System (INIS)

    Zhu Aiping; Lu Yan; Si Yunfeng; Dai Sheng

    2011-01-01

    Rod-like hydroxyapatite (HAp) nanoparticles with various aspect ratios are synthesized by means of low-temperature hydrothermal method in the presence of a N-[(2-hydroxy-3-trimethylammonium) propyl]chitosan chloride (HTCC) template. The synthesized HAps were examined by X-ray diffraction (XRD), Fourier transform infrared spectrophotometer (FTIR) and transmission electron microscopy (TEM) techniques. The results reveal that HAps are rod-like monocrystals, where the size and morphology can be tailored by varying synthesis conditions, such as pH, hydrothermal synthesis temperature and the ratio of PO 4 3- to the quaternary ammonium in HTCC. The mechanism of HTCC template on HAp nanorod preparation is analyzed.

  18. Frabicating hydroxyapatite nanorods using a biomacromolecule template

    Science.gov (United States)

    Zhu, Aiping; Lu, Yan; Si, Yunfeng; Dai, Sheng

    2011-02-01

    Rod-like hydroxyapatite (HAp) nanoparticles with various aspect ratios are synthesized by means of low-temperature hydrothermal method in the presence of a N-[(2-hydroxy-3-trimethylammonium) propyl]chitosan chloride (HTCC) template. The synthesized HAps were examined by X-ray diffraction (XRD), Fourier transform infrared spectrophotometer (FTIR) and transmission electron microscopy (TEM) techniques. The results reveal that HAps are rod-like monocrystals, where the size and morphology can be tailored by varying synthesis conditions, such as pH, hydrothermal synthesis temperature and the ratio of PO43- to the quaternary ammonium in HTCC. The mechanism of HTCC template on HAp nanorod preparation is analyzed.

  19. Composite biocompatible hydroxyapatite-silk fibroin coatings for medical implants obtained by Matrix Assisted Pulsed Laser Evaporation

    International Nuclear Information System (INIS)

    Miroiu, F.M.; Socol, G.; Visan, A.; Stefan, N.; Craciun, D.; Craciun, V.; Dorcioman, G.; Mihailescu, I.N.; Sima, L.E.; Petrescu, S.M.; Andronie, A.; Stamatin, I.; Moga, S.; Ducu, C.

    2010-01-01

    The aim of this study was to obtain biomimetic inorganic-organic thin films as coatings for metallic medical implants. These contain hydroxyapatite, the inorganic component of the bony tissues, and a natural biopolymer - silk fibroin - added in view to induce the surface functionalization. Hydroxyapatite (HA), silk fibroin (FIB) and composite HA-FIB films were obtained by Matrix Assisted Pulsed Laser Evaporation (MAPLE) in order to compare their physical and biological performances as coatings on metallic prostheses. We used an excimer laser source (KrF*, λ = 248 nm, τ = 25 ns) operated at 10 Hz repetition rate. Coatings were deposited on quartz, Si and Ti substrates and then subjected to physical (FTIR, XRD, AFM, SEM) analyses, correlated with the results of the cytocompatibility in vitro tests. The hybrid films were synthesized from frozen targets of aqueous suspensions with 3:2 or 3:4 weight ratio of HA:FIB. An appropriate stoichiometric and functional transfer was obtained for 0.4-0.5 J/cm 2 laser fluence. FTIR spectra of FIB and HA-FIB films exhibited distinctive absorption maxima, in specific positions of FIB random coil form: 1540 cm -1 amide II, 1654 cm -1 amide I, 1243 cm -1 amide III, while the peak from 1027 cm -1 appeared only for HA and composite films. Osteosarcoma SaOs2 cells cultured 72 h on FIB and HA-FIB films showed increased viability, good spreading and normal cell morphology. The well-elongated, flattened cells are a sign of an appropriate interaction with the MAPLE FIB and composite HA-FIB coatings.

  20. Composite biocompatible hydroxyapatite-silk fibroin coatings for medical implants obtained by Matrix Assisted Pulsed Laser Evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Miroiu, F.M., E-mail: marimona.miroiu@inflpr.ro [National Institute for Lasers, Plasma, and Radiation Physics, 409 Atomistilor Street, RO-77125, MG-36, Magurele-Ilfov (Romania); Socol, G.; Visan, A.; Stefan, N.; Craciun, D.; Craciun, V.; Dorcioman, G.; Mihailescu, I.N. [National Institute for Lasers, Plasma, and Radiation Physics, 409 Atomistilor Street, RO-77125, MG-36, Magurele-Ilfov (Romania); Sima, L.E.; Petrescu, S.M. [Institute of Biochemistry, Romanian Academy, 296 Splaiul Independentei, 060031 Bucharest (Romania); Andronie, A.; Stamatin, I. [3Nano-SAE Alternative Energy Sources-University of Bucharest, Faculty of Physics, 409 Atomistilor Street, RO-77125, Magurele-Ilfov (Romania); Moga, S.; Ducu, C. [University of Pitesti, Targul din Vale Str, no. 1, 110040 Pitesti (Romania)

    2010-05-25

    The aim of this study was to obtain biomimetic inorganic-organic thin films as coatings for metallic medical implants. These contain hydroxyapatite, the inorganic component of the bony tissues, and a natural biopoly