WorldWideScience

Sample records for 3-dimensional hydrogel system

  1. Hydrogel Based 3-Dimensional (3D System for Toxicity and High-Throughput (HTP Analysis for Cultured Murine Ovarian Follicles.

    Hong Zhou

    Full Text Available Various toxicants, drugs and their metabolites carry potential ovarian toxicity. Ovarian follicles, the functional unit of the ovary, are susceptible to this type of damage at all stages of their development. However, despite of the large scale of potential negative impacts, assays that study ovarian toxicity are limited. Exposure of cultured ovarian follicles to toxicants of interest served as an important tool for evaluation of toxic effects for decades. Mouse follicles cultured on the bottom of a culture dish continue to serve an important approach for mechanistic studies. In this paper, we demonstrated the usefulness of a hydrogel based 3-dimensional (3D mouse ovarian follicle culture as a tool to study ovarian toxicity in a different setup. The 3D in vitro culture, based on fibrin alginate interpenetrating network (FA-IPN, preserves the architecture of the ovarian follicle and physiological structure-function relationship. We applied the novel 3D high-throughput (HTP in vitro ovarian follicle culture system to study the ovotoxic effects of an anti-cancer drug, Doxorobucin (DXR. The fibrin component in the system is degraded by plasmin and appears as a clear circle around the encapsulated follicle. The degradation area of the follicle is strongly correlated with follicle survival and growth. To analyze fibrin degradation in a high throughput manner, we created a custom MATLAB® code that converts brightfield micrographs of follicles encapsulated in FA-IPN to binary images, followed by image analysis. We did not observe any significant difference between manually processed images to the automated MATLAB® method, thereby confirming that the automated program is suitable to measure fibrin degradation to evaluate follicle health. The cultured follicles were treated with DXR at concentrations ranging from 0.005 nM to 200 nM, corresponding to the therapeutic plasma levels of DXR in patients. Follicles treated with DXR demonstrated decreased

  2. Hydrogel based occlusion systems

    Stam, F.A.; Jackson, N.; Dubruel, P.; Adesanya, K.; Embrechts, A.; Mendes, E.; Neves, H.P.; Herijgers, P.; Verbrugghe, Y.; Shacham, Y; Engel, L.; Krylov, V.

    2013-01-01

    A hydrogel based occlusion system, a method for occluding vessels, appendages or aneurysms, and a method for hydrogel synthesis are disclosed. The hydrogel based occlusion system includes a hydrogel having a shrunken and a swollen state and a delivery tool configured to deliver the hydrogel to a target occlusion location. The hydrogel is configured to permanently occlude the target occlusion location in the swollen state. The hydrogel may be an electro-activated hydrogel (EAH) which could be ...

  3. Hydrogel based occlusion systems

    Stam, F.A.; Jackson, N.; Dubruel, P.; Adesanya, K.; Embrechts, A.; Mendes, E.; Neves, H.P.; Herijgers, P.; Verbrugghe, Y.; Shacham, Y.; Engel, L.; Krylov, V.

    2013-01-01

    A hydrogel based occlusion system, a method for occluding vessels, appendages or aneurysms, and a method for hydrogel synthesis are disclosed. The hydrogel based occlusion system includes a hydrogel having a shrunken and a swollen state and a delivery tool configured to deliver the hydrogel to a tar

  4. 3-Dimensional cell-laden nano-hydroxyapatite/protein hydrogels for bone regeneration applications

    Sadat-Shojai, Mehdi, E-mail: msadatshojai@gmail.com [Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of); Department of Biomaterials, Iran Polymer and Petrochemical Institute, Tehran (Iran, Islamic Republic of); Khorasani, Mohammad-Taghi [Department of Biomaterials, Iran Polymer and Petrochemical Institute, Tehran (Iran, Islamic Republic of); Jamshidi, Ahmad [Department of Novel Drug Delivery Systems, Iran Polymer and Petrochemical Institute, Tehran (Iran, Islamic Republic of)

    2015-04-01

    The ability to encapsulate cells in three-dimensional (3D) protein-based hydrogels is potentially of benefit for tissue engineering and regenerative medicine. However, as a result of their poor mechanical strength, protein-based hydrogels have traditionally been considered for soft tissue engineering only. Hence, in this study we tried to render these hydrogels suitable for hard tissue regeneration, simply by incorporation of bioactive nano-hydroxyapatite (HAp) into a photocrosslinkable gelatin hydrogel. Different cell types were also encapsulated in three dimensions in the resulting composites to prepare cell-laden constructs. According to the results, HAp significantly improves the stiffness of gelatin hydrogels, while it maintains their structural integrity and swelling ratio. It was also found that while the bare hydrogel (control) was completely inert in terms of bioactivity, a homogeneous 3D mineralization occurs throughout the nanocomposites after incubation in simulated body fluid. Moreover, encapsulated cells readily elongated, proliferated, and formed a 3D interconnected network with neighboring cells in the nanocomposite, showing the suitability of the nano-HAp/protein hydrogels for cellular growth in 3D. Therefore, the hydrogel nanocomposites developed in this study may be promising candidates for preparing cell-laden tissue-like structures with enhanced stiffness and increased osteoconductivity to induce bone formation in vivo. - Highlights: • We tried to render protein-based hydrogels suitable for hard tissue regeneration. • We developed a three-component system comprising hydrogel, nano-HAp, and cells. • Nano-HAp significantly improved the mechanical strength of hydrogel. • Encapsulated cells readily elongated and proliferated in 3D cell-laden nanocomposite. • 3D deposition of bone crystals occurred in the hydrogel nanocomposites.

  5. Classification of solvable 3-dimensional Lie triple systems

    Bouetou, Thomas Bouetou

    2003-01-01

    We give the classification of solvable and splitting Lie triple system and it turn that, up to isomorphism there exist 7 non isomorphic canonical Lie triple systems and 6 non isomorphic splitting canonical Lie triple systems and find the solvable Lie algebras associated.

  6. Auto-measuring System of 3- Dimensional Human Body

    李勇; 尚保平; 付小莉; 尚会超

    2001-01-01

    To realize the automation of fashion industry measuring,designing and manufacturing, the auto-measurement of 3D size of human body is of great importance. The auto measurement system of 3D human body based on Charge Coupled Devices (CCD) and infrared sensors is presented in this paper. The system can measure the bare size of human body that excludes the effect of clothing quickly and accurately.

  7. The 3-dimensional Einstein-Klein-Gordon system in characteristic numerical relativity

    Barreto, W.; Da Silva, A.; Gomez, R.; Lehner, L.; Rosales, L.; Winicour, J.

    2005-01-01

    We incorporate a massless scalar field into a 3-dimensional code for the characteristic evolution of the gravitational field. The extended 3-dimensional code for the Einstein--Klein--Gordon system is calibrated to be second order convergent. It provides an accurate calculation of the gravitational and scalar radiation at infinity. As an application, we simulate the fully nonlinear evolution of an asymmetric scalar pulse of ingoing radiation propagating toward an interior Schwarzschild black h...

  8. Bio-functionalized silk hydrogel microfluidic systems.

    Zhao, Siwei; Chen, Ying; Partlow, Benjamin P; Golding, Anne S; Tseng, Peter; Coburn, Jeannine; Applegate, Matthew B; Moreau, Jodie E; Omenetto, Fiorenzo G; Kaplan, David L

    2016-07-01

    Bio-functionalized microfluidic systems were developed based on a silk protein hydrogel elastomeric materials. A facile multilayer fabrication method using gelatin sacrificial molding and layer-by-layer assembly was implemented to construct interconnected, three dimensional (3D) microchannel networks in silk hydrogels at 100 μm minimum feature resolution. Mechanically activated valves were implemented to demonstrate pneumatic control of microflow. The silk hydrogel microfluidics exhibit controllable mechanical properties, long-term stability in various environmental conditions, tunable in vitro and in vivo degradability in addition to optical transparency, providing unique features for cell/tissue-related applications than conventional polydimethylsiloxane (PDMS) and existing hydrogel-based microfluidic options. As demonstrated in the work here, the all aqueous-based fabrication process at ambient conditions enabled the incorporation of active biological substances in the bulk phase of these new silk microfluidic systems during device fabrication, including enzymes and living cells, which are able to interact with the fluid flow in the microchannels. These silk hydrogel-based microfluidic systems offer new opportunities in engineering active diagnostic devices, tissues and organs that could be integrated in vivo, and for on-chip cell sensing systems. PMID:27077566

  9. Study of new chaotic flows on a family of 3-dimensional systems with quadratic nonlinearities

    Based on a wider systematic search on a family of 3-dimensional systems with quadratic nonlinearities, three new simple chaotic systems were found. One of them has the unusual feature of having a stable equilibrium point, and it is the simplest one of other chaotic flows with this property. The others have some interesting special properties

  10. DYNAMICAL CONSISTENCE IN 3-DIMENSIONAL TYPE-K COMPETITIVE LOTKA-VOLTERRA SYSTEM

    2012-01-01

    A 3-dimensional type-K competitive Lotka-Volterra system is considered in this paper. Two discretization schemes are applied to the system with an positive interior fixed point, and two corresponding discrete systems are obtained. By analyzing the local dynamics of the corresponding discrete system near the interior fixed point, it is showed that this system is not dynamically consistent with the continuous counterpart system.

  11. 3-dimensional orthodontics visualization system with dental study models and orthopantomograms

    Zhang, Hua; Ong, S. H.; Foong, K. W. C.; Dhar, T.

    2005-04-01

    The aim of this study is to develop a system that provides 3-dimensional visualization of orthodontic treatments. Dental plaster models and corresponding orthopantomogram (dental panoramic tomogram) are first digitized and fed into the system. A semi-auto segmentation technique is applied to the plaster models to detect the dental arches, tooth interstices and gum margins, which are used to extract individual crown models. 3-dimensional representation of roots, generated by deforming generic tooth models with orthopantomogram using radial basis functions, is attached to corresponding crowns to enable visualization of complete teeth. An optional algorithm to close the gaps between deformed roots and actual crowns by using multi-quadratic radial basis functions is also presented, which is capable of generating smooth mesh representation of complete 3-dimensional teeth. User interface is carefully designed to achieve a flexible system with as much user friendliness as possible. Manual calibration and correction is possible throughout the data processing steps to compensate occasional misbehaviors of automatic procedures. By allowing the users to move and re-arrange individual teeth (with their roots) on a full dentition, this orthodontic visualization system provides an easy and accurate way of simulation and planning of orthodontic treatment. Its capability of presenting 3-dimensional root information with only study models and orthopantomogram is especially useful for patients who do not undergo CT scanning, which is not a routine procedure in most orthodontic cases.

  12. Polymer hydrogels as optimized delivery systems

    Batista, Jorge G.S.; Varca, Gustavo H.C.; Ferraz, Caroline C.; Garrido, Gabriela P.; Diniz, Bruna M.; Carvalho, Vinicius S.; Lugao, Ademar B., E-mail: jorgegabriel@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    Hydrogels are formed by polymers capable of absorbing large quantities of water. They consist of one or more three-dimensionally structured polymer networks formed by macromolecular chains linked by covalent bonds-crosslinks - and physical interactions. The application of hydrogels, has been widely studied. Biodegradable synthetic or natural polymers such as chitosan, starch and poly-lactic-co-glycolic acid, have properties that allow the development of biodegradable systems for drug and nutraceutics delivery. This study aimed to develop polymeric hydrogels based on polyvinyl alcohol, polyacrylamide and polyvinylpyrrolidone using ionizing radiation in order to develop hydrogels for improved loading and release of compounds. Polymer solutions were solubilized in water and poured into thermoformed packages. After sealing, the material was subjected to γ-irradiation at 25kGy. The samples were assayed by means of mechanical properties, gel fraction and swelling degree. Nanostructure characterization was performed using Flory's equation to determine crosslinking density. The systems developed showed swelling degree and adequate mechanical resistance. The nanostructure evaluation showed different results for each system demonstrating the need of choosing the polymer based on the specific properties of each material. (author)

  13. Influence of hydrogels initial state on their ?lectrochemical and volume-gravimetric properties ?n intergel system polyacrylic acid hydrogel ?nd poly-4-vinylpyridine hydrogel

    Jumadilov, T.; Abilov, Zh.; Kondaurov, R.; Himersen, H.; Yeskalieva, G.; Akylbekova, M.; Akimov, A.

    2015-01-01

    Electrochemical properties of intergel system polyacrylic acid (gPAA) and poly-4-vinylpyridine hydrogels (gP4VP) and conformational properties of initial hydrogels were studied depending on hydrogels initial state. Maximum activation area is: for dry hydrogels ? gPAA:gP4VP ratios 5:1 and 1:5, for swollen ? ratios 5:1, 2:4 and 1:5. ?????????? ?????????????? ??????????? ???????????? ??????? ????????? ????????????? ??????? (????) ? ???? ????-4-????????????? (??4??) ?? ????????????? ???????...

  14. Development of a 3-dimensional seismic isolation floor for computer systems

    In this paper, we investigated the applicability of a seismic isolation floor as a method for protecting computer systems from strong earthquakes, such as computer systems in nuclear power plants. Assuming that the computer system is guaranteed for 250 cm/s2 of input acceleration in the horizontal and vertical directions as the seismic performance, the basic design specification of the seismic isolation floor is considered as follows. Against S1 level earthquakes, the maximum acceleration response of the seismic isolation floor in the horizontal and vertical directions is kept less than 250 cm/s2 to maintain continuous computer operation. Against S2 level earthquakes, the isolation floor allows large horizontal movement and large displacement of the isolation devices to reduce the acceleration response, although it is not guaranteed to be less than 250 cm/s2. By reducing the acceleration response, however, serious damage to the computer systems is reduced, so that they can be restarted after an earthquake. Usually, seismic isolation floor systems permit 2-dimensional (horizontal) isolation. However, in the case of just-under-seated earthquakes, which have large vertical components, the vertical acceleration response of this system is amplified by the lateral vibration of the frame of the isolation floor. Therefore, in this study a 3-dimensional seismic isolation floor, including vertical isolation, was developed. This paper describes 1) the experimental results of the response characteristics of the 3-dimensional seismic isolation floor built as a trial using a 3-dimensional shaking table, and 2) comparison of a 2-dimensional analytical model, for motion in one horizontal direction and the vertical direction, to experimental results. (J.P.N.)

  15. Development of a 3-Dimensional Dosimetry System for Leksell Gamma Knife-Perfexion

    Yoon, KyoungJun; Kwak, Jungwon; Lee, DoHeui; Cho, Byungchul; Lee, Sangwook; Ahn, SeungDo

    2015-01-01

    The purpose of our study is to develop a new, 3-dimensional dosimetry system to verify the accuracy of dose deliveries in Leksell Gamma Knife-Perfexion TM (LGKP) (Elekta, Norcross, GA, USA). The instrument consists of a moving head phantom, an embedded thin active layer and a CCD camera system and was designed to be mounted to LGKP. As an active material concentrically located in the hemispheric head phantom, we choose Gafchromic EBT3 films and Gd2O2S;Tb phosphor sheets for dosimetric measure...

  16. 3-dimensional computer model to simulate fluid flow and contaminant transport through a rock fracture system

    A 3-dimensional fracture generating scheme is presented which can be used to simulate water flow and contaminant (solute) transport through fracture system of a rock. It is presently limited to water saturated conditions, zero permeability for the rock matrix, and steady state water flow, but allows for transient solute transport. The scheme creates finite planar plates of uniform thickness which represent fractures in 3-dimensional space. A given fracture (plate) has the following descriptors: center location, orientation, shape, areal extent and aperture. Each parameter can be described by an appropriate probability distribution. Individual fractures are generated to form an assemblage of a certain fracture density. All fracture intersections and boundary/fracture intersections are determined and deadend fractures are eliminated. Flow through the fracture assemblage is considered laminar and described by Poiseuille's law. The principle of mass conservation at each intersection is used to develop the global matrix equation, which is solved subject to specified boundary conditions to yield the head and flow distribution at each intersection. Solute transport is considered to be advective between intersections with complete mixing at each intersection. Solutes added to the flow system can be explicitly followed and concentration vs. time relationships can be determined anywhere in the system. Some examples are included

  17. A 3-Dimensional Cockpit Display with Traffic and Terrain Information for the Small Aircraft Transportation System

    UijtdeHaag, Maarten; Thomas, Robert; Rankin, James R.

    2004-01-01

    The report discusses the architecture and the flight test results of a 3-Dimensional Cockpit Display of Traffic and terrain Information (3D-CDTI). The presented 3D-CDTI is a perspective display format that combines existing Synthetic Vision System (SVS) research and Automatic Dependent Surveillance-Broadcast (ADS-B) technology to improve the pilot's situational awareness. The goal of the 3D-CDTI is to contribute to the development of new display concepts for NASA's Small Aircraft Transportation System research program. Papers were presented at the PLANS 2002 meeting and the ION-GPS 2002 meeting. The contents of this report are derived from the results discussed in those papers.

  18. Micropatterned 3-Dimensional Hydrogel System to Study Human Endothelial-Mesenchymal Stem Cell Interactions

    Trkov, Sasa; Eng, George; Di Liddo, Rosa; Parnigotto, Pier Paolo; Vunjak-Novakovic, Gordana

    2010-01-01

    The creation of vascularized engineered tissues of clinically relevant size is a major challenge of tissue engineering. While it is known that endothelial and mural vascular cells are integral to the formation of stable blood vessels, the specific cell type and optimal conditions for engineered vascular networks are poorly understood. To this end, we investigated the vasculogenic potential of human mesenchymal stem cell (MSC) populations derived from three different sources: (i) bone marrow a...

  19. 3 - Dimensional Body Measurement Technology

    ZHOU Xu-dong; LI Yan-mei

    2002-01-01

    3 - dimensional body measurement technology, the basis of developing high technology in industry, accelerates digital development of aplparel industry. This paper briefly introduces the history of 3 - dimensional body measurement technology, and recounts the principle and primary structure of some types of 3 - dimensional automatic body measurement system. With this understanding, it discusses prospect of 3- dimensional CAD and virtual technology used in apparel industry.

  20. Development of a 3-Dimensional Dosimetry System for Leksell Gamma Knife-Perfexion

    Yoon, KyoungJun; Lee, DoHeui; Cho, ByungChul; Lee, SangWook; Ahn, SeungDo

    2015-01-01

    The purpose of our study is to develop a new, 3-dimensional dosimetry system to verify the accuracy of dose deliveries in Leksell Gamma Knife-Perfexion TM (LGKP) (Elekta, Norcross, GA, USA). The instrument consists of a moving head phantom, an embedded thin active layer and a CCD camera system and was designed to be mounted to LGKP. As an active material concentrically located in the hemispheric head phantom, we choose Gafchromic EBT3 films and Gd2O2S;Tb phosphor sheets for dosimetric measurements. Also, to compensate the lack of backscatter, we located a 1 cm thick PMMA plate downstream of the active layer. The PMMA plate was transparent for scintillation lights to reach the CCD with 1200x1200 pixels by a 5.2 um pitch. Using this system, three hundred images by a 0.2 mm slice gap were acquired under each of three collimator setups, i.e. 4 mm, 8 mm, and 16 mm, respectively. The 2D projected images taken by CCD camera were compared with the dose distributions measured by EBT3 films in the same conditions. All ...

  1. Bioresponsive systems based on polygalacturonate containing hydrogels.

    Schneider, Konstantin P; Rollett, Alexandra; Wehrschuetz-Sigl, Eva; Hasmann, Andrea; Zankel, Armin; Muehlebach, Andreas; Kaufmann, Franz; Guebitz, Georg M

    2011-04-01

    Polysaccharide acid (PSA) based devices (consisting of alginic acid and polygalacturonic acid) were investigated for the detection of contaminating microorganisms. PSA-CaCl(2) hydrogel systems were compared to systems involving covalent cross-linking of PSA with glycidylmethacrylate (PSA-GMA) which was confirmed with Fourier Transformed Infrared (FTIR) analysis. Incubation of PSA-CaCl(2) and PSA-GMA beads loaded with Alizarin as a model ingredient with trigger enzymes (polygalacturonases or pectate lyases) or bacteria lead to a smoothening of the surface and exposure of Alizarin according to Environmental Scanning Electron Microscopy (ESEM) analysis. Enzyme triggered release of Alizarin was demonstrated for a commercial enzyme preparation from Aspergillus niger and with purified polygalacturonase and pectate lyase from S. rolfsii and B. pumilus, respectively. In contrast to the PSA-CaCl(2) beads, cross-linking (PSA-GMA beads) restricted the release of Alizarin in absence of enzymes. There was a linear relation between release of Alizarin (5-348 μM) and enzyme activity in a range of 0-300 U ml(-1) dosed. In addition to enzymes, both PSA-CaCl(2) and PSA-GMA beads were incubated with Bacillus subtilis and Yersinia entercolitica as model contaminating microorganism. After 72 h, a release between 10 μM and 57 μM Alizarin was detected. For protection of the hydrogels, an enzymatically modified PET membrane was covalently attached onto the surface. This lead to a slower release and improve long term storage stability based on less than 1% release of dye after 21 days. Additionally, this allowed simple detection by visual inspection of the device due to a colour change of the white membrane to orange upon enzyme triggered release of the dye. PMID:22112943

  2. SBNCT plan: A 3-dimensional treatment planning system for boron neutron capture therapy

    The need for accurate and comprehensive 3-dimensional treatment planning for boron neutron capture therapy (BNCT) has been debated for the past several years. Although many argue against the need for elaborate and expensive treatment planning programs which mimic conventional radiotherapy planning systems, it is clear that in order to realize significant gains over conventional fractionated radiation therapy, patients must be treated to the edge of normal tissue tolerance. Just how close to this edge is dictated by the uncertainties in dosimetry. Hence the focus of BNCT planning is the determination of dose distribution throughout normal tissue volumes. Although precise geometric manipulation of the epithermal neutron beam is not achievable, the following variables play an important role in BNCT optimization: patient orientation, dose fractionation, number of fields, megawatt-minutes per fraction, use of surface bolus, and use of collimation. Other variables which are not as easily adjustable and would not, therefore, be part of treatment planning optimization, include external patient contour, internal patient heterogeneities, boron compound distributions, and RBE's. The boron neutron capture therapy planning system developed at SUNY Stony Brook (SBNCT-Plan) was designed as an interactive graphic tool to assist the radiation oncologist in generating the optimum plan for a neutron capture treatment

  3. A 60GHz-Band 3-Dimensional System-in-Package Transmitter Module with Integrated Antenna

    Suematsu, Noriharu; Yoshida, Satoshi; Tanifuji, Shoichi; Kameda, Suguru; Takagi, Tadashi; Tsubouchi, Kazuo

    A low cost, ultra small Radio Frequency (RF) transceiver module with integrated antenna is one of the key technologies for short range millimeter-wave wireless communication. This paper describes a 60GHz-band transmitter module with integrated dipole antenna. The module consists of three pieces of low-cost organic resin substrate. These substrates are vertically stacked by employing Cu ball bonding 3-dimensional (3-D) system-in-package (SiP) technology and the MMIC's are mounted on each organic substrates by using Au-stud bump bonding (SBB) technique. The planer dipole antenna is fabricated on the top of the stacked organic substrate to avoid the influence of the grounding metal on the base substrate. At 63GHz, maximum actual gain of 6.0dBi is obtained for fabricated planar dipole antenna. The measured radiation patterns are agreed with the electro-magnetic (EM) simulated result, therefore the other RF portion of the 3-D front-end module, such as flip chip mounted IC's on the top surface of the module, does not affect the antenna characteristics. The results show the feasibility of millimeter-wave low cost, ultra small antenna integrated module using stacked organic substrates.

  4. Development of a 3-dimensional dosimetry system for Leksell Gamma Knife Perfexion

    Yoon, KyoungJun; Kwak, JungWon; Lee, DoHeui; Cho, ByungChul; Lee, SangWook; Ahn, SeungDo

    2015-07-01

    The purpose of our study is to develop a new, 3-dimensional dosimetry system to verify the accuracy of dose deliveries in Leksell Gamma Knife Perfexion (LGKP) (Elekta, Norcross, GA, USA). The instrument consists of a moving head phantom, an embedded thin active layer and a CCD camera system and was designed to be mounted to LGKP. As an active material concentrically located in the hemispheric head phantom, we choose Gafchromic EBT3 films and Gd2O2S:Tb phosphor sheets for dosimetric measurements. Also, to compensate for the lack of backscatter, we located a 1-cm-thick poly methyl methacrylate (PMMA) plate downstream of the active layer. The PMMA plate was transparent to scintillation light to reach the CCD with 1200 × 1200 pixels and a 5.2 µm pitch. With this system, 300 images with a 0.2-mm slice gap were acquired under each of three collimator setups, i.e. 4-mm, 8-mm, and 16-mm, respectively. The 2D projected images taken by the CCD camera were compared with the dose distributions measured by the EBT3 films under the same conditions. All 2D distributions were normalized to the maximum values derived by fitting peaks for each collimator setup. The differences in the full widths at half maximum (FWHM) of 2D profiles between CCD images and film doses were measured to be less than 0.3-mm. The scanning task for all peak regions took less than three minutes with the new instrument. So it can be utilized as a QA tool for the Gamma knife radiosurgery system instead of film dosimetry, the use of which requires much more time and many more resources.

  5. SU-E-T-104: Development of 3 Dimensional Dosimetry System for Gamma Knife

    Yoon, K; Kwak, J; Cho, B; Lee, D; Ahn, S [Asan Medical Center, Seoul (Korea, Republic of)

    2014-06-01

    Purpose: The aim of this study was to develop a new 3 dimensional dosimetry system to verify the dosimetric accuracy of Leksell Gamma Knife-Perfexion™ (LGK) (Elekta, Norcross, GA). Methods: We designed and manufactured a lightweight dosimetry instrument to be equipped with the head frame to LGK. It consists of a head phantom, a scintillator, a CCD camera and a step motor. The 10×10 cm2 sheet of Gd2O3;Tb phosphor or Gafchromic EBT3 film was located at the center of the 16 cm diameter hemispherical PMMA, the head phantom. The additional backscatter compensating material of 1 cm thick PMMA plate was placed downstream of the phosphor sheet. The backscatter plate was transparent for scintillation lights to reach the CCD camera with 1200×1200 pixels by 5.2 um pitch. With This equipment, 300 images with 0.2 mm of slice gap were acquired under three collimator setups (4mm, 8mm and 16mm), respectively. The 2D projected doses from 3D distributions were compared with the exposured film dose. Results: As all doses normalized by the maximum dose value in 16 mm setup, the relative differences between the equipment dose and film dose were 0.2% for 4mm collimator and 0.5% for 8mm. The acquisition of 300 images by the equipment took less than 3 minutes. Conclusion: The new equipment was verified to be a good substitute to radiochromic film, with which required more time and resources. Especially, the new methods was considered to provide much convenient and faster solution in the 3D dose acquisition for LGK.

  6. One-pot synthesis of 3-dimensional reduced graphene oxide-based hydrogel as support for microbe immobilization and BOD biosensor preparation.

    Liu, Ling; Zhai, Junfeng; Zhu, Chengzhou; Gao, Ying; Wang, Yue; Han, Yanchao; Dong, Shaojun

    2015-01-15

    We report a hydrothermal method to prepare reduced graphene oxide (rGO)-based hydrogel (Gel(rGONR)), using neutral red (NR) to mediate the assembly of rGO sheets and tune the pore size of Gel(rGONR). A series of techniques including scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy and BET were employed to characterize the physico-chemical properties of Gel(rGONR). A large pore size of up to 20 µm and interconnected porous structure of Gel(rGONR) were obtained. Gel(rGONR) was used as a support for immobilizing microbe (denoted as Gel(rGONR-M)), which showed ~3.3 times more load mass of microbe than commonly used supports (i.e., activated carbon and carbon fiber felt) and 2.5 times higher biodegradation efficiency (BE) than carbon fiber felt. Further use of Gel(rGONR-M) as a biocatalyst for establishing a BOD biosensor exhibits a linear range of 2-64 mg O L(-1) and a detection limit 0.4 mg O L(-1) for glucose-glutamic acid (GGA). Moreover, our proposed BOD detection strategy shows a long-term viability over one year and stability up to 2 months with a relative standard deviation of 2.1%. Our results demonstrated the great potential of employing Gel(rGONR) as a microbe-immobilization support for biosensor development. PMID:25129511

  7. Study on 3-dimensional base isolation system applying to new type power plant reactor: part 2 (hydraulic 3-dimensional base-isolation system)

    Three dimensional (3D) seismic isolation devices have been developed to use for the base isolation system of the heavy building like a nuclear reactor building. The developed seismic isolation system is composed of rolling seal type air springs and the hydraulic type springs with rocking suppression system for vertical base isolation device. In horizontal direction, the same laminated rubber bearings are used as horizontal isolation device for these systems. The performances and the applicability have already been evaluated by the technical feasibility tests and performance tests for each system. In this study, it was evaluated that the performance of the 3D base isolation system with rolling seal type air springs combined with hydraulic rocking suppression devices. In this paper, the results of performance tests for hydraulic rocking suppression system will be reported. A 1/7 scaled model of the 3D base isolation devices were manufactured and some performance test were executed for each device. For the hydraulic rocking suppression system, forced dynamic loading test was carried out in order to measure the frictional and oil flow resistance force on each cylinder. And the vibration table tests were carried out with supported weight of 228 MN in order to evaluate and to confirm the horizontal and vertical isolation performance, rocking suppression performance, and the applicability of the this seismic isolation system as the combined system. 4 rolling seal type air springs and 4 hydraulic load-carrying cylinders with rocking suppression devices supported the weight. As a result, the proposed system was verified that it could be applied to the actual nuclear power plant building to be target. (authors)

  8. Application of hydrogel system for neutron attenuation

    Gupta, S C; Gupta, B P

    2000-01-01

    Hydrogel sheets based on poly(vinyl alcohol) (PVA) and poly(vinyl acetate) (PVAc) have been prepared by the technique of acetalization of PVA using formaldehyde and grafting of acrylic acid onto PVAc by gamma irradiation. PVA hydrogel (PVAB) sheets have been prepared in geometrically stable shapes by compression moulding process and characterised for their thermal properties, geometrical stability on water absorption, and neutron shielding efficiency. The effective protection from fast neutrons can be increased by a factor of 18% by swelling the PVAB sheets to 210% in water. The water intake and subsequent retention of water by the sheet can be tailored as per shielding requirements.

  9. Comparison of 3-dimensional dose reconstruction system between fluence-based system and dose measurement-guided system.

    Nakaguchi, Yuji; Ono, Takeshi; Onitsuka, Ryota; Maruyama, Masato; Shimohigashi, Yoshinobu; Kai, Yudai

    2016-01-01

    COMPASS system (IBA Dosimetry, Schwarzenbruck, Germany) and ArcCHECK with 3DVH software (Sun Nuclear Corp., Melbourne, FL) are commercial quasi-3-dimensional (3D) dosimetry arrays. Cross-validation to compare them under the same conditions, such as a treatment plan, allows for clear evaluation of such measurement devices. In this study, we evaluated the accuracy of reconstructed dose distributions from the COMPASS system and ArcCHECK with 3DVH software using Monte Carlo simulation (MC) for multi-leaf collimator (MLC) test patterns and clinical VMAT plans. In a phantom study, ArcCHECK 3DVH showed clear differences from COMPASS, measurement and MC due to the detector resolution and the dose reconstruction method. Especially, ArcCHECK 3DVH showed 7% difference from MC for the heterogeneous phantom. ArcCHECK 3DVH only corrects the 3D dose distribution of treatment planning system (TPS) using ArcCHECK measurement, and therefore the accuracy of ArcCHECK 3DVH depends on TPS. In contrast, COMPASS showed good agreement with MC for all cases. However, the COMPASS system requires many complicated installation procedures such as beam modeling, and appropriate commissioning is needed. In terms of clinical cases, there were no large differences for each QA device. The accuracy of the compass and ArcCHECK 3DVH systems for phantoms and clinical cases was compared. Both systems have advantages and disadvantages for clinical use, and consideration of the operating environment is important. The QA system selection is depending on the purpose and workflow in each hospital. PMID:27179708

  10. Smart hydrogels of thermoresponsive polymer systems

    Spěváček, Jiří

    Dalian : BIT Group Global Ltd., 2016. s. 613. [BIT´s Annual World Congress of Smart Materials /2./ - WCSM 2016. 04.03.2016-06.03.2016, Singapore] R&D Projects: GA ČR(CZ) GA13-23392S Institutional support: RVO:61389013 Keywords : thermoresponsive polymers * interpenetrating networks * hydrogels Subject RIV: CD - Macromolecular Chemistry

  11. STUDY ON ASPIRIN-MAA HYDROGEL MIP SYSTEM

    LIU Xiaohang; CHENG Guoxiang; LI Guohua

    2008-01-01

    The controUed release system of MIP-Asp hydrogel was prepared by using self-assembly molecular imprinted technique (MIP).1H NMR was used to detect the changes of active hydrogen atoms.Moreover, the effect of crosslinkin8 degree of hydrogel on the release of medicine was investigated and the temperature/pH sensitivity was also considered.The results demonstrated that: the MIPs-Asp was a procedure involving the participation of active hydrogen; the lower crosslinking degree corresponded to the higher medicine release ratio; high temperature is better for the release; weak acidity is better for the release of Asp.

  12. γ-irradiated chitosan-polyvinyl pyrrolidone hydrogels as pH-sensitive protein delivery system

    The effects of pH of the buffer solution and the composition of the hydrogel system on the bovine serum albumin (BSA) adsorption capacity of chitosan (CS)-polyvinyl pyrrolidone (PVP) (CSPVP) hydrogels and release of BSA were investigated. Poly-electrolyte CSPVP hydrogels with different compositions were prepared by irradiating CS/PVP/water mixtures with γ-rays at ambient temperature. The adsorption capacity of hydrogels was found to increase from 0 to 350 mg BSA/g dry gel, by changing external stimuli and hydrogel composition. The adsorption of BSA within CSPVP hydrogels increased with increase in CS content in the hydrogels. When the irradiation doses of hydrogel increased, the adsorption of BSA decreased. The maximum adsorption of BSA was observed at pH 5. A significant amount of the adsorbed BSA (up to 95%) was eluted in the phosphate medium containing 0.1 M NaCl at pH 7.4

  13. An injectable hyaluronic acid-tyramine hydrogel system for protein delivery.

    Lee, Fan; Chung, Joo Eun; Kurisawa, Motoichi

    2009-03-19

    Previously, we reported the independent tuning of mechanical strength (crosslinking density) and gelation rate of an injectable hydrogel system composed of hyaluronic acid-tyramine (HA-Tyr) conjugates. The hydrogels were formed through the oxidative coupling of tyramines which was catalyzed by hydrogen peroxide (H(2)O(2)) and horseradish peroxidase (HRP). Herein, we studied the encapsulation and release of model proteins using the HA-Tyr hydrogel. It was shown that the rapid gelation achieved by an optimal concentration of HRP could effectively encapsulate the proteins within the hydrogel network and thus prevented the undesired leakage of proteins into the surrounding tissues after injection. Hydrogels with different mechanical strengths were formed by changing the concentration of H(2)O(2) while maintaining the rapid gelation rate. The mechanical strength of the hydrogel controlled the release rate of proteins: stiff hydrogels released proteins slower compared to weak hydrogels. In phosphate buffer saline, alpha-amylase (negatively charged) was released sustainably from the hydrogel. Conversely, the release of lysozyme (positively charged) discontinued after the fourth hour due to electrostatic interactions with HA. In the presence of hyaluronidase, lysozymes were released continuously and completely from the hydrogel due to degradation of the hydrogel network. The activities of the released proteins were mostly retained which suggested that the HA-Tyr hydrogel is a suitable injectable and biodegradable system for the delivery of therapeutic proteins. PMID:19121348

  14. The accuracy of reformatted images using a new virtual 3-dimensional dental implant system

    Choi, Jin Seok; Kim, Eun Kyung; Han, Won Jeong [Dankook University College of Medicine, Seoul (Korea, Republic of)

    2003-09-15

    To compare the measurements of the mandible and the detectability of the mandibular canal on reformatted images using a newly developed 3-dimensional implant simulation program with traditionally used CT multiplanar reconstruction program and true measurements. Ten dry dog mandibles were used in this study. Occlusal templates for CT examination were fabricated and marked with gutta percha at ten sites. Axial CT scans were taken and reconstructed using DentaScan (D group) and Vimplant program (V group), and each mandible was sectioned at the previously marked sites (R group). Maximum vertical height (H) and maximum width (W) of the mandible, the distances from buccal border of the mandibular canal to the most buccal aspect of the mandible (X), and the distance from the superior border of the mandibular canal to the alveolar crest (Y) were measured, and the mandibular measurements in each group were compared. Detectability of mandibular canal was evaluated using a 3-point scale in both V and D groups by three oral radiologists and compared. H in the V group was slightly greater than that in the D group, and W and X in the V group was slightly less than those in the D group. H in the V group was less than that in the R group, and W and X in the V group was larger than those in the R group. The detectability of the mandibular canal did not show statistically significant differences between V and D groups. The results of the experiment show that the newly developed, inexpensive Vimplant simulation program can be used as an alternative to the traditionally used, and more expensive CT multiplanar reconstruction program.

  15. The accuracy of reformatted images using a new virtual 3-dimensional dental implant system

    To compare the measurements of the mandible and the detectability of the mandibular canal on reformatted images using a newly developed 3-dimensional implant simulation program with traditionally used CT multiplanar reconstruction program and true measurements. Ten dry dog mandibles were used in this study. Occlusal templates for CT examination were fabricated and marked with gutta percha at ten sites. Axial CT scans were taken and reconstructed using DentaScan (D group) and Vimplant program (V group), and each mandible was sectioned at the previously marked sites (R group). Maximum vertical height (H) and maximum width (W) of the mandible, the distances from buccal border of the mandibular canal to the most buccal aspect of the mandible (X), and the distance from the superior border of the mandibular canal to the alveolar crest (Y) were measured, and the mandibular measurements in each group were compared. Detectability of mandibular canal was evaluated using a 3-point scale in both V and D groups by three oral radiologists and compared. H in the V group was slightly greater than that in the D group, and W and X in the V group was slightly less than those in the D group. H in the V group was less than that in the R group, and W and X in the V group was larger than those in the R group. The detectability of the mandibular canal did not show statistically significant differences between V and D groups. The results of the experiment show that the newly developed, inexpensive Vimplant simulation program can be used as an alternative to the traditionally used, and more expensive CT multiplanar reconstruction program.

  16. The existence of periodic orbits and invariant tori for some 3-dimensional quadratic systems.

    Jiang, Yanan; Han, Maoan; Xiao, Dongmei

    2014-01-01

    We use the normal form theory, averaging method, and integral manifold theorem to study the existence of limit cycles in Lotka-Volterra systems and the existence of invariant tori in quadratic systems in ℝ(3). PMID:24982980

  17. A 3 dimensional model of the potential impacts on an aquifer of two energy storage systems

    The USGS (United States Geological Survey) SUTRA 3D flow and heat transport code has been used to model the potential for and the impacts of two ground energy storage systems sited in a geology typical of that beneath London. One system is a deep borehole closed system, the other an open injection system. The modelling results show that the impact of the closed system on the environment is small but that energy inputs or outputs must be well balanced if excessive heating or cooling of the ground is to be avoided. The open system can inject heat more efficiently but can cause a larger environmental impact depending on the nature of the site's geology. Further work needs to be undertaken to better understand the magnitude of the heat fluxes in fractured porous media. (authors)

  18. [The Family System Test: a 3-dimensional method for analyzing social relation structures].

    Gehring, T M; Funk, U; Schneider, M

    1989-01-01

    The Family System Test (FAST) is a clinically-derived figure placement technique designed for a three-dimensional representation of cohesion and power in the family. The FAST measures individual and group perceptions in typical, ideal and conflict situations. The flexibility of family structures is assessed by comparing representations of these situations. Scoring procedures as well as validity and reliability of the FAST are described. The relevance of the FAST is discussed from a systemic, developmental and clinical perspective. PMID:2740283

  19. Sustained Delivery of Chondroitinase ABC from Hydrogel System

    Filippo Rossi

    2012-03-01

    Full Text Available In the injured spinal cord, chondroitin sulfate proteoglycans (CSPGs are the principal responsible of axon growth inhibition and they contribute to regenerative failure, promoting glial scar formation. Chondroitinase ABC (chABC is known for being able to digest proteoglycans, thus degrading glial scar and favoring axonal regrowth. However, its classic administration is invasive, infection-prone and clinically problematic. An agarose-carbomer (AC1 hydrogel, already used in SCI repair strategies, was here investigated as a delivery system capable of an effective chABC administration: the material ability to include chABC within its pores and the possibility to be injected into the target tissue were firstly proved. Subsequently, release kinetic and the maintenance of enzymatic activity were positively assessed: AC1 hydrogel was thus confirmed to be a feasible tool for chABC delivery and a promising device for spinal cord injury topic repair strategies.

  20. Numerical simulation of 3-dimensional Rayleigh-Benard system by particle method

    Watanabe, Tadashi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-05-01

    As one of representative non-equilibrium thermal fluid system, there is a fluid system maintained at lower and higher temperatures at upper and lower faces, respectively, and Rayleigh-Benard (RB) system. On temperature difference between both faces smaller than a critical value, flow into the system is not developed to realize a thermal conductive state, while on that larger than a critical value, macroscopic convection vortex forms to realize a conventional thermal conductive state. A transition process from thermal conduction to convection is well-known for RB unstability and also the convection state is done for RB convection. In this paper, a transition process from thermal conduction to convection was simulated systematically by changing temperature difference at both faces using DSMC method known for one of statistical methods, to investigate the critical Rayleigh number in response to temperature difference at beginning point of the convection, variations and correlative function at proximity of the critical Rayleigh number, pattern formation of the convection and so forth. (G.K.)

  1. A novel electroporation system for efficient molecular delivery into Chlamydomonas reinhardtii with a 3-dimensional microelectrode

    Kang, Seongsu; Kim, Kwon-Ho; Kim, Yeu-Chun

    2015-11-01

    Electroporation is one of the most widely used transfection methods because of its high efficiency and convenience among the various transfection methods. Previous micro-electroporation systems have some drawbacks such as limitations in height and design, time-consuming and an expensive fabrication process due to technical constraints. This study fabricates a three dimensional microelectrode using the 3D printing technique. The interdigitated microstructure consisting of poly lactic acid was injected by a 3D printer and coated with silver and aluminum with a series of dip-coatings. With the same strength of electric field (V cm-1), a higher efficiency for molecular delivery and a higher cellular viability are achieved with the microelectrode than with a standard cuvette. In addition, this study investigates chemicophysical changes such as Joule heating and dissolved metal during electroporation and showed the micro-electroporation system had less chemicophysical changes. It was concluded that the proposed micro-electroporation system will contribute to genetic engineering as a promising delivery tool, and this combination of 3D printing and electroporation has many potential applications for diverse designs or systems.

  2. A novel electroporation system for efficient molecular delivery into Chlamydomonas reinhardtii with a 3-dimensional microelectrode.

    Kang, Seongsu; Kim, Kwon-Ho; Kim, Yeu-Chun

    2015-01-01

    Electroporation is one of the most widely used transfection methods because of its high efficiency and convenience among the various transfection methods. Previous micro-electroporation systems have some drawbacks such as limitations in height and design, time-consuming and an expensive fabrication process due to technical constraints. This study fabricates a three dimensional microelectrode using the 3D printing technique. The interdigitated microstructure consisting of poly lactic acid was injected by a 3D printer and coated with silver and aluminum with a series of dip-coatings. With the same strength of electric field (V cm(-1)), a higher efficiency for molecular delivery and a higher cellular viability are achieved with the microelectrode than with a standard cuvette. In addition, this study investigates chemicophysical changes such as Joule heating and dissolved metal during electroporation and showed the micro-electroporation system had less chemicophysical changes. It was concluded that the proposed micro-electroporation system will contribute to genetic engineering as a promising delivery tool, and this combination of 3D printing and electroporation has many potential applications for diverse designs or systems. PMID:26522846

  3. A novel electroporation system for efficient molecular delivery into Chlamydomonas reinhardtii with a 3-dimensional microelectrode

    Seongsu Kang; Kwon-Ho Kim; Yeu-Chun Kim

    2015-01-01

    Electroporation is one of the most widely used transfection methods because of its high efficiency and convenience among the various transfection methods. Previous micro-electroporation systems have some drawbacks such as limitations in height and design, time-consuming and an expensive fabrication process due to technical constraints. This study fabricates a three dimensional microelectrode using the 3D printing technique. The interdigitated microstructure consisting of poly lactic acid was ...

  4. The μSCAPE System: 3-Dimensional Profiling of Microfluidic Architectural Features Using a Flatbed Scanner

    Xu, Kerui; Liu, Qian; Jackson, Kimberly R.; Landers, James P.

    2016-02-01

    We developed a microfluidic scanner-based profile exploration system, μSCAPE, capable of generating high resolution 3D profiles of microstructure architecture in a variety of transparent substrates. The profile is obtained by scanning the dye-filled microstructure followed by absorbance calculation and the reconstruction of the optical length at each point. The power of the method was demonstrated in (1) the inspection of the variation of the cross-section of laser-ablated PDMS channel; (2) the volume of PeT chamber; and (3) the population distribution of the volumes of the micro wells in HF-etched glass and laser-ablated PDMS. The reported methods features low equipment-cost, convenient operation and large field of view (FOV), and has revealed unreported quality parameters of the tested microstructures.

  5. The μSCAPE System: 3-Dimensional Profiling of Microfluidic Architectural Features Using a Flatbed Scanner.

    Xu, Kerui; Liu, Qian; Jackson, Kimberly R; Landers, James P

    2016-01-01

    We developed a microfluidic scanner-based profile exploration system, μSCAPE, capable of generating high resolution 3D profiles of microstructure architecture in a variety of transparent substrates. The profile is obtained by scanning the dye-filled microstructure followed by absorbance calculation and the reconstruction of the optical length at each point. The power of the method was demonstrated in (1) the inspection of the variation of the cross-section of laser-ablated PDMS channel; (2) the volume of PeT chamber; and (3) the population distribution of the volumes of the micro wells in HF-etched glass and laser-ablated PDMS. The reported methods features low equipment-cost, convenient operation and large field of view (FOV), and has revealed unreported quality parameters of the tested microstructures. PMID:26924294

  6. Error analysis of a direct current electromagnetic tracking system in digitizing 3-dimensional surface geometries.

    Milne, A D; Lee, J M

    1999-01-01

    The direct current electromagnetic tracking device has seen increasing use in biomechanics studies of joint kinematics and anatomical surface geometry. In these applications, a stylus is attached to a sensor to measure the spatial location of three-dimensional landmarks. Stylus calibration is performed by rotating the stylus about a fixed point in space and using regression analysis to determine the tip offset vector. Measurement errors can be induced via several pathways, including; intrinsic system errors in sensor position or angle and tip offset calibration errors. A detailed study was performed to determine the errors introduced in digitizing small surfaces with different stylus lengths (35, 55, and 65 mm) and approach angles (30 and 45 degrees) using a plastic calibration board and hemispherical models. Two-point discrimination errors increased to an average of 1.93 mm for a 254 mm step size. Rotation about a single point produced mean errors of 0.44 to 1.18 mm. Statistically significant differences in error were observed with increasing approach angles (p < 0.001). Errors of less than 6% were observed in determining the curvature of a 19 mm hemisphere. This study demonstrates that the "Flock of Birds" can be used as a digitizing tool with accuracy better than 0.76% over 254 mm step sizes. PMID:11143353

  7. Dynamic modeling of the hydrogel molecular filter in a metamaterial biosensing system for glucose concentration estimation.

    Teutsch, T; Mesch, M; Giessen, H; Tarin, C

    2014-01-01

    We present a novel concept for ophthalmic glucose sensing using a biosensing system that consists of plasmonic dipole metamaterial covered by a layer of functionalized hydrogel. The metamaterial together with the hydrogel can be integrated into a contact lens. This optical sensor changes its properties such as reflectivity upon the ambient glucose concentration, which allows in situ measurements in the eye. The functionalization of the sensor with hydrogel allows for a glucose-specific detection, providing both selectivity and sensitivity. As a result of the presented work we derive a dynamic model of the hydrogel that can be used for further simulation studies. PMID:25570394

  8. Thiol-ene crosslinking polyamidoamine dendrimer-hyaluronic acid hydrogel system for biomedical applications.

    Bi, Xiangdong; Liang, Aiye; Tan, Yu; Maturavongsadit, Panita; Higginbothem, Ashley; Gado, Togor; Gramling, Abigail; Bahn, Hanna; Wang, Qian

    2016-06-01

    A series of alkene functionalized polyamidoamine (PAMAM) dendrimers were synthesized to prepare in situ forming hydrogels with varied gelation time and mechanical properties through crosslinking with thiolated hyaluronic acid (HS-HA). By varying the alkenyl groups on the dendrimers, the gelation time displayed a large range from 8 seconds to 18 hours, and the modulus of the hydrogels ranged from 36 to 183 Pa under experimental conditions. Investigation by (1)H-NMR spectroscopy revealed that the gelation time and the stiffness of the hydrogels were governed by the degree of electron deficiency of alkenyl groups on the dendrimers. This research provided a systematic study on the relationship between chemical structures versus gelation time and mechanical properties of hydrogels, which could guide the way to synthesize in situ forming hydrogels with designated gelation time and stiffness for biomedical applications. Further, a RGD peptide was attached to the PAMAM dendrimers to enhance cell attachment and proliferation. Viability assays of Human Umbilical Vein Endothelial Cells (HUVEC) in the synthesized hydrogels demonstrated the biocompatibility of the hydrogels after 48 hours of culturing, and the RGD peptide improved the viability of HUVEC cells in hydrogels. We believe the PAMAM/HA hydrogel system is a tuneable and biocompatible system for diverse biomedical applications. PMID:26923639

  9. Evaluation of Temperature and Stress Distribution on 2 Different Post Systems Using 3-Dimensional Finite Element Analysis

    Değer, Yalçın; Adigüzel, Özkan; Özer, Senem Yiğit; Kaya, Sadullah; Polat, Zelal Seyfioğlu; Bozyel, Bejna

    2015-01-01

    Background The mouth is exposed to thermal irritation from hot and cold food and drinks. Thermal changes in the oral cavity produce expansions and contractions in tooth structures and restorative materials. The aim of this study was to investigate the effect of temperature and stress distribution on 2 different post systems using the 3-dimensional (3D) finite element method. Material/Methods The 3D finite element model shows a labio-lingual cross-sectional view of the endodontically treated upper right central incisor and supporting periodontal ligament with bone structures. Stainless steel and glass fiber post systems with different physical and thermal properties were modelled in the tooth restored with composite core and ceramic crown. We placed 100 N static vertical occlusal loading onto the center of the incisal surface of the tooth. Thermal loads of 0°C and 65°C were applied on the model for 5 s. Temperature and thermal stresses were determined on the labio-lingual section of the model at 6 different points. Results The distribution of stress, including thermal stress values, was calculated using 3D finite element analysis. The stainless steel post system produced more temperature and thermal stresses on the restorative materials, tooth structures, and posts than did the glass fiber reinforced composite posts. Conclusions Thermal changes generated stresses in the restorative materials, tooth, and supporting structures. PMID:26615495

  10. Sericin/Dextran Injectable Hydrogel as an Optically Trackable Drug Delivery System for Malignant Melanoma Treatment.

    Liu, Jia; Qi, Chao; Tao, Kaixiong; Zhang, Jinxiang; Zhang, Jian; Xu, Luming; Jiang, Xulin; Zhang, Yunti; Huang, Lei; Li, Qilin; Xie, Hongjian; Gao, Jinbo; Shuai, Xiaoming; Wang, Guobin; Wang, Zheng; Wang, Lin

    2016-03-01

    Severe side effects of cancer chemotherapy prompt developing better drug delivery systems. Injectable hydrogels are an effective site-target system. For most of injectable hydrogels, once delivered in vivo, some properties including drug release and degradation, which are critical to chemotherapeutic effects and safety, are challenging to monitor. Developing a drug delivery system for effective cancer therapy with in vivo real-time noninvasive trackability is highly desired. Although fluorescence dyes are used for imaging hydrogels, the cytotoxicity limits their applications. By using sericin, a natural photoluminescent protein from silk, we successfully synthesized a hydrazone cross-linked sericin/dextran injectable hydrogel. This hydrogel is biodegradable and biocompatible. It achieves efficient drug loading and controlled release of both macromolecular and small molecular drugs. Notably, sericin's photoluminescence from this hydrogel is directly and stably correlated with its degradation, enabling long-term in vivo imaging and real-time monitoring of the remaining drug. The hydrogel loaded with Doxorubicin significantly suppresses tumor growth. Together, the work demonstrates the efficacy of this drug delivery system, and the in vivo effectiveness of this sericin-based optical monitoring strategy, providing a potential approach for improving hydrogel design toward optimal efficiency and safety of chemotherapies, which may be widely applicable to other drug delivery systems. PMID:26900631

  11. STUDY OF OPTICAL PROPERTIES OF ACRYLIC HYDROGEL USED IN POLLUTANTS DISPLAY SYSTEMS

    ITIN ALEKSEY L.; LUKIN SERGEY B.; USPENSKAYA MAYA V.; SOLOVIEV VALERY S.

    2012-01-01

    Results of investigations of optical properties of acrylic hydrogel used as a sensitive element in optoelectronic systems of pollutants display are presented. Spectral features and functions of the hydrogel refractive index variation under exposure to different pollutants are measured at various concentrations of polyvalent metals at room temperature.

  12. Accuracy Evaluation of a 3-Dimensional Surface Imaging System for Guidance in Deep-Inspiration Breath-Hold Radiation Therapy

    Purpose: To investigate the applicability of 3-dimensional (3D) surface imaging for image guidance in deep-inspiration breath-hold radiation therapy (DIBH-RT) for patients with left-sided breast cancer. For this purpose, setup data based on captured 3D surfaces was compared with setup data based on cone beam computed tomography (CBCT). Methods and Materials: Twenty patients treated with DIBH-RT after breast-conserving surgery (BCS) were included. Before the start of treatment, each patient underwent a breath-hold CT scan for planning purposes. During treatment, dose delivery was preceded by setup verification using CBCT of the left breast. 3D surfaces were captured by a surface imaging system concurrently with the CBCT scan. Retrospectively, surface registrations were performed for CBCT to CT and for a captured 3D surface to CT. The resulting setup errors were compared with linear regression analysis. For the differences between setup errors, group mean, systematic error, random error, and 95% limits of agreement were calculated. Furthermore, receiver operating characteristic (ROC) analysis was performed. Results: Good correlation between setup errors was found: R2=0.70, 0.90, 0.82 in left-right, craniocaudal, and anterior-posterior directions, respectively. Systematic errors were ≤0.17 cm in all directions. Random errors were ≤0.15 cm. The limits of agreement were −0.34-0.48, −0.42-0.39, and −0.52-0.23 cm in left-right, craniocaudal, and anterior-posterior directions, respectively. ROC analysis showed that a threshold between 0.4 and 0.8 cm corresponds to promising true positive rates (0.78-0.95) and false positive rates (0.12-0.28). Conclusions: The results support the application of 3D surface imaging for image guidance in DIBH-RT after BCS.

  13. Research on the use of hydrogel for the three-dimensional cell culture in microfluidic system

    Tomecka, Ewelina; Jastrzebska, ElŻbieta; Chudy, Michał; Dybko, Artur

    2014-08-01

    This paper presents a possibility of use of hydrogel in microfluidic system, which can be a promising tool for threedimensional cell culture. In the research the commercially available self-assembling peptide hydrogel Puramatrix was used. Gelation of this hydrogel is initiated by the contact with culture medium. That's why it is critical that no salts or culture medium come in contact with this hydrogel until gelation is desired. The geometry of the designed microdevice enables hydrodynamic focusing of liquid hydrogel-cells mixture and then gelation of the mixture in the middle of the main microchannel due to the flow of the culture medium. As a sheath fluid sucrose solution was used. It provides also, in the first stage, isolation of culture medium (containing gelling salts) from liquid mixture of hydrogel and cells. When the flow of sucrose solution is turned off, the culture medium starts to be in contact to the hydrogel mixed with cell. As a result, simultaneously gelation of the hydrogel and encapsulation of cells in it are successfully achieved.

  14. Development of sustained antimicrobial-release systems using poly(2-hydroxyethyl methacrylate)/trimethylolpropane trimethacrylate hydrogels.

    Kitagawa, Haruaki; Takeda, Kahoru; Kitagawa, Ranna; Izutani, Naomi; Miki, Saeki; Hirose, Nanako; Hayashi, Mikako; Imazato, Satoshi

    2014-10-01

    Reconstructive materials with sustained antimicrobial effects could be useful for preventing infectious diseases in an environment containing indigenous bacteria or fungi such as the oral cavity. With the objective of applying a non-biodegradable hydrogel to resin-based materials as a reservoir for water-soluble antimicrobials, novel hydrogels consisting of 2-hydroxyethyl methacrylate (HEMA) and trimethylolpropane trimethacrylate (TMPT) were fabricated. Cetylpyridinium chloride (CPC) was loaded into five hydrogels comprising different ratios of HEMA/TMPT, and their ability to release as well as to be recharged with CPC was examined in vitro. A polyHEMA/TMPT hydrogel comprising 50% HEMA/50% TMPT could be effectively loaded and recharged with CPC by immersion into a CPC solution, demonstrating the longest release of CPC, above the concentration required to inhibit bacteria and fungi. The binding of CPC to the hydrogels was mainly through hydrophobic interaction. Loading of CPC into a hydrogel by mixing CPC powder with the HEMA/TMPT monomer before polymerization resulted in marked extension of the initial CPC-release period. The CPC-pre-mixed hydrogel was confirmed to exhibit antibacterial activity by agar diffusion tests. It is possible to achieve a sustained release system for antimicrobials by pre-mix loading and recharging CPC into a 50% HEMA/50% TMPT hydrogel. PMID:24952074

  15. A modified emulsion gelation technique to improve buoyancy of hydrogel tablets for floating drug delivery systems.

    Yom-Tov, Ortal; Seliktar, Dror; Bianco-Peled, Havazelet

    2015-10-01

    The use of buoyant or floating hydrogel tablets is of particular interest in the sustained release of drugs to the stomach. They have an ability to slow the release rates of drugs by prolonging their absorption window in the upper part of the gastrointestinal (GI) tract. In this study we synthesized bioactive hydrogels that have sustainable release rates for drugs in the stomach based on a hydrogel preparation technique that employs emulsifying surfactants. The emulsion gelation technique, which encapsulates oil droplets within the hydrogels during crosslinking, was used to decrease their specific gravity in aqueous environments, resulting in floating drug release depots. Properties such as swelling, buoyancy, density and drug release were manipulated by changing the polymer concentrations, surfactant percentages and the oil:polymer ratios. The relationship between these properties and the hydrogel's floating lag time was documented. The potential for this material to be used as a floating drug delivery system was demonstrated. PMID:26117764

  16. Design of a Drug-Delivery System Based On Polyacrylamide Hydrogels. Evaluation of Structural Properties

    Ferreira, L; Vidal, M. M.; Gil, M. H.

    2001-01-01

    It is well known that hydrogels can be suitable for biomedical, agricultural, and industrial applications. In particular, they have been widely used for the preparation of drug-delivery systems. The preparation and characterization of such a system should be useful for introducing students to these materials. This paper describes the preparation of polyacrylamide hydrogels having different crosslinking densities from the view of optimizing this system for acetylsalicylic acid (aspirin) releas...

  17. Hydrogel microspheres from biodegradable polymers as drug delivery systems

    A series of hydrogel microspheres were prepared from pectin, a hydrophilic biopolymer, and zein, a hydrophobic biopolymer, at varying weight ratios. The hydrogel formulation was conducted in the presence of calcium or other divalent metal ions at room temperature under mild conditions. Studies of ...

  18. Oxygen transmissibility of piggyback systems with conventional soft and silicone hydrogel contact lenses

    López-Alemany, António; González-Méijome, José Manuel; Almeida, José B.; Parafita, Manuel A.; Refojo, Miguel F.

    2006-01-01

    To investigate the apparent oxygen transmissibility of various piggyback systems using conventional and silicone hydrogel soft contact lenses of different water content and permeability, rigid poly(methyl methacrylate), and rigid gas-permeable lenses of medium, high, and ultrahigh oxygen permeability. The aim of the study was to establish which material (rigid or hydrogel) is more representative of the resulting oxygen performance of piggyback systems. METHODS: The apparent oxygen transmissib...

  19. Advanced biomaterials for repairing the nervous system: what can hydrogels do for the brain?

    Khaing, Zin Z.; Richelle C. Thomas; Geissler, Sydney A.; Schmidt, Christine E.

    2014-01-01

    Newly developed hydrogels are likely to play significant roles in future therapeutic strategies for the nervous system. In this review, unique features of the central nervous system (i.e., the brain and spinal cord) that are important to consider in developing engineered biomaterials for therapeutic applications are discussed. This review focuses on recent findings in hydrogels as biomaterials for use as (1) drug delivery devices, specifically focusing on how the material can change the deliv...

  20. Smart hydrogel-functionalized textile system with moisture management property for skin application

    In this study, a functional textile-based material for topical skin application was fabricated by coating a thermoresponsive hydrogel onto one side of absorbent nonwoven fabric. The thermoresponsive hydrogel was synthesized easily through coupling of poly (ethylene glycol) (PEG) and poly (ϵ-caprolactone) (PCL) with hexamethylene diisocyanate (HMDI) as a chemical linker. The chemical structure of the as-prepared triblock copolymer hydrogel was unraveled by FTIR and 1H NMR analysis. The hydrogel showed a temperature-triggered sol-gel transition behavior and high potential for use as drug controlled release. When the surrounding temperature was close to the skin temperature of around 34 °C, it became a moisture management system where the liquids including sweat, blood, and other body fluids can be transported unidirectionally from one fabric side with the hydrophobic hydrogel coating to the untreated opposite side. This thereby showed that the thermoresponsive hydrogel-coated textile materials had a function to keep topical skin area clean, breathable, and comfortable, thus suggesting a great potential and significance for long-term skin treatment application. The structure and surface morphology of the thermoresponsive hydrogel, in vitro drug release behavior, and the mechanism of unidirectional water transport were investigated in detail. Our success in preparation of the functional textile composites will pave the way for development of various polymer- or textile-based functional materials that are applicable in the real world. (paper)

  1. Smart hydrogel-functionalized textile system with moisture management property for skin application

    Wang, Xiaowen; Hu, Huawen; Yang, Zongyue; He, Liang; Kong, Yeeyee; Fei, Bin; Xin, John H.

    2014-12-01

    In this study, a functional textile-based material for topical skin application was fabricated by coating a thermoresponsive hydrogel onto one side of absorbent nonwoven fabric. The thermoresponsive hydrogel was synthesized easily through coupling of poly (ethylene glycol) (PEG) and poly (ɛ-caprolactone) (PCL) with hexamethylene diisocyanate (HMDI) as a chemical linker. The chemical structure of the as-prepared triblock copolymer hydrogel was unraveled by FTIR and 1H NMR analysis. The hydrogel showed a temperature-triggered sol-gel transition behavior and high potential for use as drug controlled release. When the surrounding temperature was close to the skin temperature of around 34 °C, it became a moisture management system where the liquids including sweat, blood, and other body fluids can be transported unidirectionally from one fabric side with the hydrophobic hydrogel coating to the untreated opposite side. This thereby showed that the thermoresponsive hydrogel-coated textile materials had a function to keep topical skin area clean, breathable, and comfortable, thus suggesting a great potential and significance for long-term skin treatment application. The structure and surface morphology of the thermoresponsive hydrogel, in vitro drug release behavior, and the mechanism of unidirectional water transport were investigated in detail. Our success in preparation of the functional textile composites will pave the way for development of various polymer- or textile-based functional materials that are applicable in the real world.

  2. Radiation syntheses of Pectin/acrylamide (PEC/PAM) and Pectin/Diethylaminoethylmethacrylate (PEC/DEAMA) hydrogels as drug delivery systems

    Different pH responsive copolymer hydrogels based on pectin were prepared by the effect of radiation. The physical and chemical properties of prepared hydrogels were studied by FTIR, and TGA. Also, the prepared hydrogels were evaluated for the possible use as drug delivery system for chlortetracycline HCL as model drug. The results revealed that the swelling ratios and the release behavior of hydrogels depend mainly on the pH of the medium and the hydrogel composition. (author)

  3. Kinetic Degradation and Controlled Drug Delivery System Studies for Sensitive Hydrogels Prepared by Gamma Irradiation

    Ternary mixtures of N-vinyle-2-pyrrolidone(NVP ), itaconic acid (IA) and gelatin (G) were gamma irradiated to prepared poly(NVP/IA/G) hydrogels. The equilibrium kinetic swelling, drug release behavior, Scan Electron Microscope (SEM) and the swelling-degradation kinetics were studied. Both the diffusion exponent and the diffusion coefficient increase with increasing content of (IA). Also, the swelling behavior of copolymer hydrogels in response to ph value of the external media was studied, it is noted that the highest swelling values at ph 4. The in vitro drug release behavior of these hydrogels was examined by quantification analysis with a UV/VIS spectrophotometers. Chlorpromazine hydrochloride was loaded into dried hydrogels to investigate the stimuli-sensitive property at the specific ph. The release studies show that the highest value of release was at ph 4 which can be used for drug delivery system

  4. Halloysite Nanotube Composited Thermo-responsive Hydrogel System for Controlled-release

    林茜; 巨晓洁; 谢锐; 江明月; 魏竭; 褚良银

    2013-01-01

    Halloysite nanotube-composited thermo-responsive hydrogel system has been successfully developed for controlled drug release by copolymerization of N-isopropylacrylamide (NIPAM) with silane-modified halloysite nanotubes (HNT) through thermally initiated free-radical polymerization. With methylene blue as a model drug, thermo-responsive drug release results demonstrate that the drug release from the nanotubes in the composited hy-drogel can be well controlled by manipulating the environmental temperature. When the hydrogel network is swol-len at temperature below the lower critical solution temperature (LCST), drug releases steadily from lumens of the embedded nanotubes, whereas the drug release stops when hydrogel shrinks at temperature above the LCST. The release of model drug from the HNT-composited hydrogel matches well with its thermo-responsive volume phase transition, and shows characteristics of well controlled release. The design strategy and release results of the pro-posed novel HNT-composited thermo-responsive hydrogel system provide valuable guidance for designing respon-sive nanocomposites for controlled-release of active agents.

  5. Stimuli-sensitive hydrogels: A novel ophthalmic drug delivery system

    Singh Vinod

    2010-01-01

    Full Text Available Background: Stimuli-sensitive hydrogels are three-dimensional, hydrophilic, polymeric networks capable of imbibing large amounts of water or biological fluids on stimulation, such as pH, temperature and ionic change. Aim: To develop hydrogels that are sensitive to stimuli, i.e. pH, in the cul-de-sac of the eye for providing a prolonged effect and increased bioavailability with reduction in frequency of administration. Materials and Methods: Hydrogels were formulated by using timolol maleate as the model drug, polyacrylic acid as the gelling agents, hydroxyl ethyl cellulose as the viscolizer and sodium chloride as the isotonic agent. Stirring of ingredients in pH 4 phosphate buffer at high speed was carried out. The dynamic dialysis technique was used for drug release studies. In vivo study for reduction in intraocular pressure was carried out by using albino rabbits. Statistical Analysis: Drug release studies data were used for statistical analysis in first-order plots, Higuchi plots and Peppas exponential plots. Student t-test was performed for in vivo study. Results: Viscosity of the hydrogel increases from 3.84 cps to 9.54 cps due to change in pH 4 to pH 7.4. The slope value of the Peppas equation was found to be 0.3081, 0.3743 and 0.2964. Up to 80% of drug was released in an 8 h drug release study. Sterile hydrogels with no ocular irritation were obtained. Conclusions: Hydrogels show increase in viscosity due to change in pH. Hydrogels were therapeutically effacious, stable, non-irritant and showed Fickian diffusion. In vivo results clearly show a prolonged reduction in intraocular pressure, which was helpful for reduction in the frequency of administration.

  6. Investigation on a hydrogel based passive thermal management system for lithium ion batteries

    An appropriate operating temperature range is critical for the overall performance and safety of lithium-ion batteries. Considering the excellent performance of water in heat dissipation in industrial applications, in this paper, a water based PAAS (sodium polyacrylate) hydrogel thermal management system has been proposed to handle the heat surge during the operation of a Li-ion battery pack. A thermal model with constant heat generation rate is employed to simulate the high current discharge process (i.e., 10 A) on a 4S1P battery pack, which shows a good consistence with the corresponding experimental results. Further experiments on 4S1P and 5S1P battery packs validate the effectiveness of the hydrogel thermal management system in lowering the temperature increase rate of battery packs at different discharge rates and minimizing the temperature difference inside battery packs during operation, thereby enhancing the stability and safety in continuous charge and discharge process and decreasing the capacity fading rate during life cycle tests. This novel hydrogel based cooling system also possesses the characteristics of high energy efficiency, easy manufacturing process, compactness, and low cost. - Highlights: • A hydrogel thermal management system (TMS) is proposed for Li-ion battery. • It is found that the heat from internal resistance predominates at high discharge rate. • Effectiveness of hydrogel in controlling cell temperature is proved. • Battery equipped with hydrogel TMS is safer at continuous high rate cycle test. • The capacity fading rate of battery pack decreases when hydrogel TMS is implemented

  7. Preparation and characterization of superporous hydrogels as gastroretentive drug delivery system for rosiglitazone maleate

    N Vishal Gupta

    2010-09-01

    Full Text Available "n  "nBackground and the purpose of the study: Many drugs which have narrow therapeutic window and are absorbed mainly in stomach have been developed as gastroretentive delivery system. Rosiglitazone maleate, an anti-diabetic, is highly unstable at basic pH and is extensively absorbed from the stomach. Hence there is a need to develop a gastroretentive system. In this study a superporous hydrogel was developed as a gastroretentive drug delivery system. "nMethods: Chitosan/poly(vinyl alcohol interpenetrating polymer network type superporous hydrogels were prepared using a gas foaming method employing glyoxal as the crosslinking agent for Rosiglitazone maleate. Sodium bicarbonate was applied as a foaming agent to introduce the porous structure. Swelling behaviors of superporous hydrogel in acidic solution were studied to investigate their applications for gastric retention device. The optimum preparation condition of superporous hydrogels was obtained from the gelation kinetics. FT-IR, scanning electron microscopy, porosity and swelling ratio studies were used to characterize these polymers. In vitro drug release studies were also carried out. "nResults: The introduction of a small amount of Poly(Vinyl Alcohol enhanced the mechanical strength but slightly reduced the swelling ratio. The prepared superporous hydrogels were highly sensitive to pH of swelling media, and showed reversible swelling and de-swelling behaviors maintaining their mechanical stability. The degradation kinetics in simulated gastric fluid showed that it had biodegradability. Swelling was dependent on the amount of chitosan and crosslinker. The drug release from superporous hydrogels was sustained for 6 hrs. Major Conclusion: The studies showed that chitosan-based superporous hydrogels could be used as a gastroretentive drug delivery system for rosiglitazone maleate in view of their swelling and prolonged drug release characteristics in acidic pH.

  8. Alginate based hydrogel as a potential biopolymeric carrier for drug delivery and cell delivery systems: present status and applications.

    Giri, Tapan Kumar; Thakur, Deepa; Alexander, Amit; Ajazuddin; Badwaik, Hemant; Tripathi, Dulal Krishna

    2012-11-01

    Alginate is a non-toxic, biocompatible and biodegradable natural polymer with a number of peculiar physicochemical properties for which it has wide applications in drug delivery and cell delivery systems. Hydrogel formation can be obtained by interactions of anionic alginates with multivalent inorganic cations by simple ionotropic gelation method. Hydrophilic polymeric network of three dimensional cross linked structures of hydrogels absorb substantial amount of water or biological fluids. Among the numerous biomaterials used for hydrogel formation alginate has been and will continue to be one of the most important biomaterial. Therefore, in view of the vast literature support, we focus in this review on alginate - based hydrogel as drug delivery and cell delivery carriers for biomedical applications. Various properties of alginates, their hydrogels and also various techniques used for preparing alginate hydrogels have been reviewed. PMID:22998675

  9. Hydrogels as scaffolds and delivery systems to enhance axonal regeneration after injuries

    Oscar A. Carballo-Molina

    2015-02-01

    Full Text Available Damage caused to neural tissue by disease or injury frequently produces a discontinuity in the nervous system. Such damage generates diverse alterations that are commonly permanent, due to the limited regeneration capacity of the adult nervous system, particularly the Central Nervous System (CNS. The cellular reaction to noxious stimulus leads to several events such as the formation of glial and fibrous scars, which inhibit axonal regeneration in both the CNS and the Peripheral Nervous System (PNS. Although in the PNS there is some degree of nerve regeneration, it is common that the growing axons reinnervate incorrect areas, causing mismatches. Providing a permissive substrate for axonal regeneration in combination with delivery systems for the release of molecules, which enhances axonal growth, could increase regeneration and the recovery of functions in the CNS or the PNS. Currently, there are no effective vehicles to supply growth factors or cells to the damaged/diseased nervous system. Hydrogels are polymers that are biodegradable, biocompatible and have the capacity to deliver a large range of molecules in situ. The inclusion of cultured neural cells into hydrogels forming three-dimensional structures allows the formation of synapses and neuronal survival. There is also evidence showing that hydrogels constitute an amenable substrate for axonal growth of endogenous or grafted cells, overcoming the presence of axonal regeneration inhibitory molecules, in both the central and peripheral nervous systems. Recent experiments suggest that hydrogels can carry and deliver several proteins relevant for improving neuronal survival and axonal growth. Although the use of hydrogels is appealing, its effectiveness is still a matter of discussion, and more results are needed to achieve consistent recovery using different parameters. This review also discusses areas of opportunity where hydrogels can be applied, in order to promote axonal regeneration of

  10. Efficacy of nonhormonal vaginal contraceptives from a hydrogel delivery system.

    Saxena, B B; Singh, M; Gospin, R M; Chu, C C; Ledger, W J

    2004-09-01

    This investigation describes the synthesis of a biodegradable hydrogel composed of a core surrounded by four concentric sheaths containing dextran, copolymers of polylactide and epsilon-caprolactone. The hydrogel was impregnated with iron (II) d-gluconate dihydrate, which causes complete spermiostasis due to lipid peroxidation, ascorbic acid to increase the viscosity of the cervical mucus and mixtures of polyamino and polycarboxylic acids to sustain vaginal pH close to 4.5. The combined effects of the agents in the daily eluates of the hydrogel were efficacious up to 16 days, within 30 s, as shown by sperm penetration tests. For in vivo studies, rabbits were chosen as the experimental model because they are easy to handle and the female is always in estrus. The anterior vagina of estrous female rabbits was instilled with the hydrogel, and then inseminated with the semen from a fertile male. Postinsemination flush from the female rabbits showed that all of the sperm were dead. These observations demonstrate the potential for the development of a biocompatible, nonhormonal, intravaginal contraceptive device. PMID:15325890

  11. Radiation synthesis of stimuli-responsive hydrogels and the application to intelligent drug delivery systems

    Radiation-prepared synthetic and natural polyelectrolyte and polyampholite hydrogels were applied to the intelligent drug delivery systems (DDS). The intelligent membranes and chips were prepared by nano-porous fabrication with Eximalaser and ion-beam irradiations and the coating of stimuli-responsive hydrogels. This coating was efficiently carried out by curing processing with conveyer system. Computer programming control of intelligent drug releases was studied for the design of DDS chips to carry out the multiple drug delivery in response to multiple environmental changes. (author)

  12. Polymer hydrogel functionalized with biodegradable nanoparticles as composite system for controlled drug delivery

    The possibility to direct pharmacological treatments targeting specific cell lines using polymer nanoparticles is one of the main novelties and perspectives in nanomedicine. However, sometimes, the ability to maintain NPs localized at the site of the injection that work as a drug reservoir can represent a good and complementary option. In this direction we built a composite material made of polymeric hydrogel functionalized with polymer NPs. ϵ-caprolactone and polyethylene glycol have been copolymerized in a two-step synthesis of PEGylated NPs, while hydrogel was synthesized through polycondensation between NPs, agarose and branched polyacrylic acid. NP functionalization was verified with Fourier transform infrared spectroscopy (FTIR), high resolution magic angle spinning-nuclear magnetic resonance (HRMAS-NMR) spectroscopy and release kinetics from a hydrogel matrix and compared with NPs only physically entrapped into a hydrogel matrix. The characteristics of the resulting composite hydrogel-NPs system were studied both in terms of rheological properties and in its ability to sustain the release of To-Pro3, used as a drug mimetic compound to represent a promising drug delivery device. (paper)

  13. A Study on the System and Method for Drawing 3-Dimensional Cable Object with the cable tracking Navigation

    3D cable tracking system with navigation makes it possible to easily search the objects which users want to retrieve and to measure the visual, spatial and structural distance by connecting the existing cable management system with 3D cable tracking system with navigation. With this consideration, we hope to create a more advanced cable management system in the future. I would like to describes the management system and method of the cable installed in the nuclear power plant, and how to build the database of the system. More specifically, it will be operated to the maintenance and management function, and the life management system of the cable, describing the creation method of three-dimensional cable object formed by the information of trace route through navigation and how to build the system database automatically

  14. A Study on the System and Method for Drawing 3-Dimensional Cable Object with the cable tracking Navigation

    Bhang, Keugjin; Jung, Sunchul [Central Research Institute, Daejeon (Korea, Republic of); Hong, Junhee [Chungnam Univ., Daejeon (Korea, Republic of)

    2013-05-15

    3D cable tracking system with navigation makes it possible to easily search the objects which users want to retrieve and to measure the visual, spatial and structural distance by connecting the existing cable management system with 3D cable tracking system with navigation. With this consideration, we hope to create a more advanced cable management system in the future. I would like to describes the management system and method of the cable installed in the nuclear power plant, and how to build the database of the system. More specifically, it will be operated to the maintenance and management function, and the life management system of the cable, describing the creation method of three-dimensional cable object formed by the information of trace route through navigation and how to build the system database automatically.

  15. Preparation of open porous polycaprolactone microspheres and their applications as effective cell carriers in hydrogel system

    Zhang, Qingchun [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering (China); Tan, Ke; Ye, Zhaoyang [State Key Laboratory of Bioreactor Engineering, School of Bioengineering, East China University of Science and Technology, Shanghai, 200237 China (China); Zhang, Yan, E-mail: zhang_yan@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering (China); Tan, Wensong [State Key Laboratory of Bioreactor Engineering, School of Bioengineering, East China University of Science and Technology, Shanghai, 200237 China (China); Lang, Meidong, E-mail: mdlang@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering (China)

    2012-12-01

    Common hydrogel, composed of synthetic polymers or natural polysaccharides could not support the adhesion of anchorage-dependent cells due to the lack of cell affinitive interface and high cell constraint. The use of porous polyester microspheres as cell-carriers and introduction of cell-loaded microspheres into the hydrogel system might overcome the problem. However, the preparation of the open porous microsphere especially using polycaprolactone (PCL) has been rarely reported. Here, the open porous PCL microspheres were fabricated via the combined emulsion/solvent evaporation and particle leaching method. The microspheres exhibited porous surface and inter-connective pore structure. Additionally, the pore structure could be easily controlled by adjusting the processing parameters. The surface pore size could be altered from 20 {mu}m to 80 {mu}m and the internal porosities were varied from 30% to 70%. The obtained microspheres were evaluated to delivery mesenchymal stem cells (MSCs) and showed the improved cell adhesion and growth when compared with the non-porous microspheres. Then, the MSCs loaded microspheres were introduced into agarose hydrogel. MSCs remained alive and sustained proliferation in microsphere/agarose composite in 5-day incubation while a decrement of MSCs viabilities was found in agarose hydrogel without microspheres. The results indicated that the microsphere/hydrogel composite had a great potential in cell therapy and injectable system for tissue regeneration. Highlights: Black-Right-Pointing-Pointer The open porous polycaprolactone microspheres were fabricated using paraffin as a porogen. Black-Right-Pointing-Pointer The microspheres exhibited porous surface and inter-connective pore structure. Black-Right-Pointing-Pointer The surface and internal pore size and porosity of microsphere could be controlled. Black-Right-Pointing-Pointer The porous microspheres exhibited an improved cell adhesion and proliferation. Black

  16. Preparation of open porous polycaprolactone microspheres and their applications as effective cell carriers in hydrogel system

    Common hydrogel, composed of synthetic polymers or natural polysaccharides could not support the adhesion of anchorage-dependent cells due to the lack of cell affinitive interface and high cell constraint. The use of porous polyester microspheres as cell-carriers and introduction of cell-loaded microspheres into the hydrogel system might overcome the problem. However, the preparation of the open porous microsphere especially using polycaprolactone (PCL) has been rarely reported. Here, the open porous PCL microspheres were fabricated via the combined emulsion/solvent evaporation and particle leaching method. The microspheres exhibited porous surface and inter-connective pore structure. Additionally, the pore structure could be easily controlled by adjusting the processing parameters. The surface pore size could be altered from 20 μm to 80 μm and the internal porosities were varied from 30% to 70%. The obtained microspheres were evaluated to delivery mesenchymal stem cells (MSCs) and showed the improved cell adhesion and growth when compared with the non-porous microspheres. Then, the MSCs loaded microspheres were introduced into agarose hydrogel. MSCs remained alive and sustained proliferation in microsphere/agarose composite in 5-day incubation while a decrement of MSCs viabilities was found in agarose hydrogel without microspheres. The results indicated that the microsphere/hydrogel composite had a great potential in cell therapy and injectable system for tissue regeneration. Highlights: ► The open porous polycaprolactone microspheres were fabricated using paraffin as a porogen. ► The microspheres exhibited porous surface and inter-connective pore structure. ► The surface and internal pore size and porosity of microsphere could be controlled. ► The porous microspheres exhibited an improved cell adhesion and proliferation. ► Mesenchymal stem cells survived and proliferated in microsphere/hydrogel composite.

  17. Hydrogel-laden paper scaffold system for origami-based tissue engineering.

    Kim, Su-Hwan; Lee, Hak Rae; Yu, Seung Jung; Han, Min-Eui; Lee, Doh Young; Kim, Soo Yeon; Ahn, Hee-Jin; Han, Mi-Jung; Lee, Tae-Ik; Kim, Taek-Soo; Kwon, Seong Keun; Im, Sung Gap; Hwang, Nathaniel S

    2015-12-15

    In this study, we present a method for assembling biofunctionalized paper into a multiform structured scaffold system for reliable tissue regeneration using an origami-based approach. The surface of a paper was conformally modified with a poly(styrene-co-maleic anhydride) layer via initiated chemical vapor deposition followed by the immobilization of poly-l-lysine (PLL) and deposition of Ca(2+). This procedure ensures the formation of alginate hydrogel on the paper due to Ca(2+) diffusion. Furthermore, strong adhesion of the alginate hydrogel on the paper onto the paper substrate was achieved due to an electrostatic interaction between the alginate and PLL. The developed scaffold system was versatile and allowed area-selective cell seeding. Also, the hydrogel-laden paper could be folded freely into 3D tissue-like structures using a simple origami-based method. The cylindrically constructed paper scaffold system with chondrocytes was applied into a three-ring defect trachea in rabbits. The transplanted engineered tissues replaced the native trachea without stenosis after 4 wks. As for the custom-built scaffold system, the hydrogel-laden paper system will provide a robust and facile method for the formation of tissues mimicking native tissue constructs. PMID:26621717

  18. Evolution of the 3-dimensional video system for facial motion analysis: ten years' experiences and recent developments.

    Tzou, Chieh-Han John; Pona, Igor; Placheta, Eva; Hold, Alina; Michaelidou, Maria; Artner, Nicole; Kropatsch, Walter; Gerber, Hans; Frey, Manfred

    2012-08-01

    Since the implementation of the computer-aided system for assessing facial palsy in 1999 by Frey et al (Plast Reconstr Surg. 1999;104:2032-2039), no similar system that can make an objective, three-dimensional, quantitative analysis of facial movements has been marketed. This system has been in routine use since its launch, and it has proven to be reliable, clinically applicable, and therapeutically accurate. With the cooperation of international partners, more than 200 patients were analyzed. Recent developments in computer vision--mostly in the area of generative face models, applying active--appearance models (and extensions), optical flow, and video-tracking-have been successfully incorporated to automate the prototype system. Further market-ready development and a business partner will be needed to enable the production of this system to enhance clinical methodology in diagnostic and prognostic accuracy as a personalized therapy concept, leading to better results and higher quality of life for patients with impaired facial function. PMID:21734549

  19. An introduction to the 3-dimensional virtual library sites-navigation system at Capital Normal University Library

    Shuo; WANG; Xiaoli; HU

    2011-01-01

    Capital Normal University Library(CNU Library)initiated the first practical application of a 3D virtual library sites-navigation system(an electronic kiosk version)among Chinese academic and research libraries in 2010.It was primarily based on the technologies of 3DsMax and Virtools.This paper concentrates on the discussion of the methods in creating the 3D model and in realizing the interaction among the data usage of the system.As a result,several important service functions of the system have been developed successfully so far for convenient public access.They include the functions of virtual-book searching,path navigation online,real-time message exchanges,and multi-media sharing,etc.

  20. Real-time 3-dimensional virtual reality navigation system with open MRI for breast-conserving surgery

    We report here the early experiences using a real-time three-dimensional (3D) virtual reality navigation system with open magnetic resonance imaging (MRI) for breast-conserving surgery (BCS). Two patients with a non-palpable MRI-detected breast tumor underwent BCS under the guidance of the navigation system. An initial MRI for the breast tumor using skin-affixed markers was performed immediately prior to excision. A percutaneous intramammary dye marker was applied to delineate an excision line, and the computer software '3D Slicer' generated a real-time 3D virtual reality model of the tumor and the puncture needle in the breast. Under guidance by the navigation system, marking procedures were performed without any difficulties. Fiducial registration errors were 3.00 mm for patient no.1, and 4.07 mm for patient no.2. The real-time 3D virtual reality navigation system with open MRI is feasible for safe and accurate excision of non-palpable MRI-detected breast tumors. (author)

  1. DOORS, 1-,2-,3-dimensional discrete-ordinates system for deep-penetration neutron and photon transport

    1 - Description of program or function: The DOORS3.2a discrete ordinates transport code system includes the most recent versions of CCC-0543/TORT-DORT, CCC-0254/ANISN-ORNL, CCC-0628/GBANISN and CCC-0351/FALSTF. It also includes the ISOPLOT code from the PSR-0155/DOGS package and various utility programs listed below which were previously included in the TORT-DORT package. In this release each module is a separate executable file. Several modules, as needed, can be run in a single job by using 'jdos' to call the 'drv' module which interprets the sequence specified in the input. TORT calculates the flux of fluence of particles due to particles incident upon the system from extraneous sources or generated internally as a result of interaction with the system in two-or three-dimensional geometric systems, and DORT is used in one- or two-dimensional geometric systems. The principle application is to the deep-penetration transport of neutrons and photons. Reactor eigenvalue problems can also be solved. Numerous printed edits of the results are available, and results can be transferred to output files for subsequent analysis. ANISN solves the one-dimensional Boltzmann transport equation for neutrons or gamma rays in slab, spherical, or cylindrical geometry. GBANISN is based on ANISN but was modified to allow randomizing of multi-bank fluxes within a group at all interfaces between dissimilar materials and a reduction in the number of outer iterations for problems involving neutron up-scatter into higher energy groups. GBANISN requires fewer outer iterations than ANISN by performing 'inner iterations' over energy groups within a 'band' and converging those groups before moving to the next band. These 'inner' iterations slightly resemble outer iterations in ANISN. Thus, a calculation with up-scatter and no fission can be solved with one traditional outer iteration. GBANISN, like ANISN, includes a technique for handling general anisotropic scattering, pointwise convergence

  2. Contrast enhanced micro-computed tomography resolves the 3-dimensional morphology of the cardiac conduction system in mammalian hearts.

    Robert S Stephenson

    Full Text Available The general anatomy of the cardiac conduction system (CCS has been known for 100 years, but its complex and irregular three-dimensional (3D geometry is not so well understood. This is largely because the conducting tissue is not distinct from the surrounding tissue by dissection. The best descriptions of its anatomy come from studies based on serial sectioning of samples taken from the appropriate areas of the heart. Low X-ray attenuation has formerly ruled out micro-computed tomography (micro-CT as a modality to resolve internal structures of soft tissue, but incorporation of iodine, which has a high molecular weight, into those tissues enhances the differential attenuation of X-rays and allows visualisation of fine detail in embryos and skeletal muscle. Here, with the use of a iodine based contrast agent (I(2KI, we present contrast enhanced micro-CT images of cardiac tissue from rat and rabbit in which the three major subdivisions of the CCS can be differentiated from the surrounding contractile myocardium and visualised in 3D. Structures identified include the sinoatrial node (SAN and the atrioventricular conduction axis: the penetrating bundle, His bundle, the bundle branches and the Purkinje network. Although the current findings are consistent with existing anatomical representations, the representations shown here offer superior resolution and are the first 3D representations of the CCS within a single intact mammalian heart.

  3. Preparation and characterization of superporous hydrogels as gastroretentive drug delivery system for rosiglitazone maleate

    N. Vishal Gupta; Shivakumar, H. G.

    2010-01-01

    Background and the purpose of the study Many drugs which have narrow therapeutic window and are absorbed mainly in stomach have been developed as gastroretentive delivery system. Rosiglitazone maleate, an anti-diabetic, is highly unstable at basic pH and is extensively absorbed from the stomach. Hence there is a need to develop a gastroretentive system. In this study a superporous hydrogel was developed as a gastroretentive drug delivery system. Methods Chitosan/poly(vinyl alcohol) interpenet...

  4. Preparation and characterization of superporous hydrogels as gastroretentive drug delivery system for rosiglitazone maleate

    N. Vishal Gupta; Shivakumar, H. G.

    2010-01-01

    "n  "nBackground and the purpose of the study: Many drugs which have narrow therapeutic window and are absorbed mainly in stomach have been developed as gastroretentive delivery system. Rosiglitazone maleate, an anti-diabetic, is highly unstable at basic pH and is extensively absorbed from the stomach. Hence there is a need to develop a gastroretentive system. In this study a superporous hydrogel was developed as a gastroretentive drug delivery system. "nMethods: Chito...

  5. A Hydrogel-Based Epirubicin Delivery System for Intravesical Chemotherapy

    Ching-Wen Liu

    2016-06-01

    Full Text Available This study aimed to examine the efficacy of epirubicin-loaded gelatin hydrogel (EPI-H in the treatment of superficial urothelium carcinoma. Hydrogel was prepared by Schiff base-crosslinking of gelatin with glutaraldehyde. EPI-H exhibited high entrapment efficiency (59.87% ± 0.51%. EPI-H also increased epirubicin accumulation in AY-27 cells when compared with the effect of aqueous solutions of epirubicin (EPI-AQ; respective epirubicin-positive cell counts were 69.0% ± 7.6% and 38.3% ± 5.8%. EPI-H also exhibited greater cytotoxicity against AY-27 cells than that of EPI-AQ; IC50 values were 13.1 ± 1.1 and 7.5 ± 0.3 μg/mL, respectively. Cystometrograms showed that EPI-H reduced peak micturition, threshold pressures, and micturition duration, and that it increased bladder compliance more so than EPI-AQ. EPI-H enhanced epirubicin penetration into basal cells of urothelium in vivo, whereas EPI-AQ did so only to the umbrella cells. EPI-H inhibited tumor growth upon intravesical instillation to tumor-bearing bladder of F344 rats, inducing higher levels of caspase-3 expression than that observed with EPI-AQ treatment; the number of caspase-3 positive cells in treated urothelium carcinoma was 13.9% ± 4.0% (EPI-AQ and 34.1% ± 1.0%, (EPI-H. EPI-H has value as an improved means to administer epirubicin in intravesical instillation treatments for bladder cancer.

  6. Advanced biomaterials for repairing the nervous system: what can hydrogels do for the brain?

    Zin Z. Khaing

    2014-09-01

    Full Text Available Newly developed hydrogels are likely to play significant roles in future therapeutic strategies for the nervous system. In this review, unique features of the central nervous system (i.e., the brain and spinal cord that are important to consider in developing engineered biomaterials for therapeutic applications are discussed. This review focuses on recent findings in hydrogels as biomaterials for use as (1 drug delivery devices, specifically focusing on how the material can change the delivery rate of small molecules, (2 scaffolds that can modify the post-injury environment, including preformed and injectable scaffolds, (3 cell delivery vehicles, discussing cellular response to natural and synthetic polymers as well as structured and amorphous materials, and (4 scaffolds for tissue regeneration, describing micro- and macro-architectural constructs that have been designed for neural applications. In addition, key features in each category that are likely to contribute to the translational success of these biomaterials are highlighted.

  7. Development of 3-D Hydrogel Culture Systems With On-Demand Cell Separation

    Hamilton, Sharon K.; Bloodworth, Nathaniel C.; Massad, Christopher S.; Hammoudi, Taymour M.; Suri, Shalu; Yang, Peter J.; Lu, Hang; Temenoff, Johnna S.

    2013-01-01

    Recently there has been an increased interest in the effects of paracrine signaling between groups of cells, particularly in the context of better understanding how stem cells contribute to tissue repair. Most current 3-D co-culture methods lack the ability to effectively separate 2 cell populations after the culture period, which is important for simultaneously analyzing the reciprocal effects of each cell type on the other. Here, we detail the development of a 3-D hydrogel co-culture system...

  8. Controlled drug delivery through a novel PEG hydrogel encapsulated silica aerogel system.

    Giray, Seda; Bal, Tuğba; Kartal, Ayse M; Kızılel, Seda; Erkey, Can

    2012-05-01

    A novel composite material consisting of a silica aerogel core coated by a poly(ethylene) glycol (PEG) hydrogel was developed. The potential of this novel composite as a drug delivery system was tested with ketoprofen as a model drug due to its solubility in supercritical carbon dioxide. The results indicated that both drug loading capacity and drug release profiles could be tuned by changing hydrophobicity of aerogels, and that drug loading capacity increased with decreased hydrophobicity, while slower release rates were achieved with increased hydrophobicity. Furthermore, higher concentration of PEG diacrylate in the prepolymer solution of the hydrogel coating delayed the release of the drug which can be attributed to the lower permeability at higher PEG diacrylate concentrations. The novel composite developed in this study can be easily implemented to achieve the controlled delivery of various drugs and/or proteins for specific applications. PMID:22374682

  9. A composite hydrogel system containing glucose-responsive nanocarriers for oral delivery of insulin.

    Li, Lei; Jiang, Guohua; Yu, Weijiang; Liu, Depeng; Chen, Hua; Liu, Yongkun; Huang, Qin; Tong, Zaizai; Yao, Juming; Kong, Xiangdong

    2016-12-01

    Development of an oral delivery strategy for insulin therapeutics has drawn much attention in recent years. In this study, a glucose-responsive nanocarriers for loading of insulin has been prepared firstly. The resultant nanocarriers exhibited relative low cytotoxicity against Caco-2 cells and excellent stability against protein solution. The insulin release behaviors were evaluated triggered by pH and glucose in vitro. In order to enhance the oral bioavailability of insulin, the insulin-loaded glucose-responsive nanocarriers were further encapsulated into a three-dimensional (3D) hyaluronic acid (HA) hydrogel environment for overcoming multiple barriers and providing multi-protection for insulin during the transport process. The hypoglycemic effect for oral delivery of insulin was studied in vivo. After oral administration to the diabetic rats, the released insulin from hydrogel systems containing insulin-loaded glucose-responsive nanocarriers exhibited an effective hypoglycemic effect for longer time compared with insulin-loaded nanocarriers. PMID:27612686

  10. Modified chitosan hydrogels as drug delivery and tissue engineering systems: present status and applications

    Tapan Kumar Giri

    2012-10-01

    Full Text Available Chitosan, a natural cationic polysaccharide, is prepared industrially by the hydrolysis of the aminoacetyl groups of chitin, a naturally available marine polymer. Chitosan is a non-toxic, biocompatible and biodegradable polymer and has attracted considerable interest in a wide range of biomedical and pharmaceutical applications including drug delivery, cosmetics, and tissue engineering. The primary hydroxyl and amine groups located on the backbone of chitosan are responsible for the reactivity of the polymer and also act as sites for chemical modification. However, chitosan has certain limitations for use in controlled drug delivery and tissue engineering. These limitations can be overcome by chemical modification. Thus, modified chitosan hydrogels have gained importance in current research on drug delivery and tissue engineering systems. This paper reviews the general properties of chitosan, various methods of modification, and applications of modified chitosan hydrogels.

  11. 3-dimensional polymer gel dosimetry

    Recently developed techniques in conformal radiotherapy demand special properties of radiation dosimeters. Polymer gel dosimeter evaluated by nuclear magnetic resonance (NMR) is promising tool which can be used for measuring rather complicated 3-dimensional dose distributions with required precision of ± 5 %. This system is based on radiation-induced polymerisation and cross-linking of acrylic monomers which are uniformly dispersed in aqueous gel. The formation of cross-linked polymers in the irradiated regions of the gel increases the NMR relaxation rates of neighbouring water protons. BANG-2 type polymer gel was prepared. The composition of gel dosimeter was as follows: 3 % N,N'-methylene-bisacrylamide, 3 % acrylic acid, 1 % sodium hydroxide, 5 % gelatine, and 88 % water, where all percentages are by weight. The dosimeters in glass vessels were homogeneously irradiated by 60Co gamma photons in a Gammacell 220 unit and by 4 MV, 6 MV and 18 MV X ray photons on Varian Clinac 600C and 2100 C linear accelerators by doses in the range of 0-50 Gy. Evaluation of dosimeters was performed on Siemens EXPERT 1 T and Siemens VISION 1,5 T scanners. Multi-echo CPMG sequence with 16 echoes was used for the evaluation of T2-relaxation times in irradiated gel dosimeters. The dependence of 1/T2 response of dosimeters was studied on following factors: absorbed dose, energy of applied radiation, temperature during NMR evaluation, time since irradiation to NMR evaluation and strength of the magnetic field. An exponential dependence of 1/T2 response on absorbed dose in the range of 0-50 Gy was observed, in the range 0-10 Gy the data could be fitted by a linear function. There was observed no dependence of 1/T2 response on: energy (for three different photon energies used in this study), strength of magnetic field of NMR scanner, time from irradiation of the dosimeters to NMR evaluation. Increase of gel dosimeter 1/T2 response with the decrease of the temperature during NMR evaluation

  12. Development of crosslinked methylcellulose hydrogels for soft tissue augmentation using an ammonium persulfate-ascorbic acid redox system.

    Gold, Gittel T; Varma, Devika M; Taub, Peter J; Nicoll, Steven B

    2015-12-10

    Hydrogels composed of methylcellulose are candidate materials for soft tissue reconstruction. Although photocrosslinked methylcellulose hydrogels have shown promise for such applications, gels crosslinked using reduction-oxidation (redox) initiators may be more clinically viable. In this study, methylcellulose modified with functional methacrylate groups was polymerized using an ammonium persulfate (APS)-ascorbic acid (AA) redox initiation system to produce injectable hydrogels with tunable properties. By varying macromer concentration from 2% to 4% (w/v), the equilibrium moduli of the hydrogels ranged from 1.47 ± 0.33 to 5.31 ± 0.71 kPa, on par with human adipose tissue. Gelation time was found to conform to the ISO standard for injectable materials. Cellulase treatment resulted in complete degradation of the hydrogels within 24h, providing a reversible corrective feature. Co-culture with human dermal fibroblasts confirmed the cytocompatibility of the gels based on DNA measurements and Live/Dead imaging. Taken together, this evidence indicates that APS-AA redox-polymerized methylcellulose hydrogels possess properties beneficial for use as soft tissue fillers. PMID:26428151

  13. REVIEW: CHITOSAN BASED HYDROGEL POLYMERIC BEADS – AS DRUG DELIVERY SYSTEM

    Manjusha Rani

    2010-11-01

    Full Text Available Chitosan obtained by alkaline deacetylation of chitin is a non-toxic, biocompatible, and biodegradable natural polymer. Chitosan-based hydrogel polymeric beads have been extensively studied as micro- or nano-particulate carriers in the pharmaceutical and medical fields, where they have shown promise for drug delivery as a result of their controlled and sustained release properties, as well as biocompatibility with tissue and cells. To introduce desired properties and enlarge the scope of the potential applications of chitosan, graft copolymerization with natural or synthetic polymers on it has been carried out, and also, various chitosan derivatives have been utilized to form beads. The desired kinetics, duration, and rate of drug release up to therapeutical level from polymeric beads are limited by specific conditions such as beads material and their composition, bead preparation method, amount of drug loading, drug solubility, and drug polymer interaction. The present review summarizes most of the available reports about compositional and structural effects of chitosan-based hydrogel polymeric beads on swelling, drug loading, and releasing properties. From the studies reviewed it is concluded that chitosan-based hydrogel polymeric beads are promising drug delivery systems.

  14. Hyaluronic acid based hydrogel system for soft tissue regeneration and drug delivery

    Jha, Amit Kumar

    We have developed hyaluronic acid (HA)-based, biomimetic hydrogel matrices that are hierarchically structured, mechanically robust and biologically active. Specifically, HA-based hydrogel particles (HGPs) with controlled sizes, defined porosity, and improved stability were synthesized using different inverse emulsion systems and crosslinking chemistries. The resultant particles either contained residual functional groups or were rendered reactive by subsequent chemical modifications. HA-based doubly crosslinked networks (DXNs) were synthesized via covalent crosslinking of HA HGPs with soluble HA macromers carrying mutually reactive functional groups. These hybrid matrices are hierarchical in nature, consisting of densely crosslinked HGPs integrated in a loosely connected secondary matrix. Their mechanical properties and degradation kinetics can be readily tuned by varying the particle size, functional group density, intra- and interparticle crosslinking. To improve the biological functions of HA HGPs, perlecan domain I (PlnDI), a basement membrane proteoglycan that has strong affinity for various heparin binding growth factors (HBGFs), was successfully conjugated to the particles through the core protein via a flexible poly(ethylene glycol) (PEG) linker. The immobilized PlnDI maintains its ability to bind bone morphogenetic proteins (BMP-2) and modulates its in vitro release. A similar, sustained release of BMP-2 was achieved by encapsulating BMP-2-loaded HGPs within a photocrosslinked HA matrix. When encapsulated in HA DXNs, primary bovine chondrocytes were able to maintain their phenotype, proliferate readily and produce abundant glycosaminoglycan. Finally, cell-adhesive HA DXNs were fabricated by encapsulating gelatin-decorated HA HGPs in a secondary HA matrix. Human MSCs were shown to adhere to the composite matrix through the focal adhesion sites clustered on particle surface. The cell-adhesive composite matrices supported hMSC proliferation and migration into

  15. EGF and curcumin co-encapsulated nanoparticle/hydrogel system as potent skin regeneration agent.

    Li, Xiaoling; Ye, Xianlong; Qi, Jianying; Fan, Rangrang; Gao, Xiang; Wu, Yunzhou; Zhou, Liangxue; Tong, Aiping; Guo, Gang

    2016-01-01

    Wound healing is a complex multifactorial process that relies on coordinated signaling molecules to succeed. Epidermal growth factor (EGF) is a mitogenic polypeptide that stimulates wound repair; however, precise control over its application is necessary to reduce the side effects and achieve desired therapeutic benefits. Moreover, the extensive oxidative stress during the wound healing process generally inhibits repair of the injured tissues. Topical applications of antioxidants like curcumin (Cur) could protect tissues from oxidative damage and significantly improve tissue remodeling. To achieve much accelerated wound healing effects, we designed a novel dual drug co-loaded in situ gel-forming nanoparticle/hydrogel system (EGF-Cur-NP/H) which acted not only as a supportive matrix for the regenerative tissue, but also as a sustained drug depot for EGF and Cur. In the established excisional full-thickness wound model, EGF-Cur-NP/H treatment significantly enhanced wound closure through increasing granulation tissue formation, collagen deposition, and angiogenesis, relative to normal saline, nanoparticle/hydrogel (NP/H), Cur-NP/H, and EGF-NP/H treated groups. In conclusion, this study provides a biocompatible in situ gel-forming system for efficient topical application of EGF and Cur in the landscape of tissue repair. PMID:27574428

  16. Modulation of Dental Pulp Stem Cell Odontogenesis in a Tunable PEG-Fibrinogen Hydrogel System.

    Lu, Qiqi; Pandya, Mirali; Rufaihah, Abdul Jalil; Rosa, Vinicius; Tong, Huei Jinn; Seliktar, Dror; Toh, Wei Seong

    2015-01-01

    Injectable hydrogels have the great potential for clinical translation of dental pulp regeneration. A recently developed PEG-fibrinogen (PF) hydrogel, which comprises a bioactive fibrinogen backbone conjugated to polyethylene glycol (PEG) side chains, can be cross-linked after injection by photopolymerization. The objective of this study was to investigate the use of this hydrogel, which allows tuning of its mechanical properties, as a scaffold for dental pulp tissue engineering. The cross-linking degree of PF hydrogels could be controlled by varying the amounts of PEG-diacrylate (PEG-DA) cross-linker. PF hydrogels are generally cytocompatible with the encapsulated dental pulp stem cells (DPSCs), yielding >85% cell viability in all hydrogels. It was found that the cell morphology of encapsulated DPSCs, odontogenic gene expression, and mineralization were strongly modulated by the hydrogel cross-linking degree and matrix stiffness. Notably, DPSCs cultured within the highest cross-linked hydrogel remained mostly rounded in aggregates and demonstrated the greatest enhancement in odontogenic gene expression. Consistently, the highest degree of mineralization was observed in the highest cross-linked hydrogel. Collectively, our results indicate that PF hydrogels can be used as a scaffold for DPSCs and offers the possibility of influencing DPSCs in ways that may be beneficial for applications in regenerative endodontics. PMID:26124841

  17. Modulation of Dental Pulp Stem Cell Odontogenesis in a Tunable PEG-Fibrinogen Hydrogel System

    Qiqi Lu

    2015-01-01

    Full Text Available Injectable hydrogels have the great potential for clinical translation of dental pulp regeneration. A recently developed PEG-fibrinogen (PF hydrogel, which comprises a bioactive fibrinogen backbone conjugated to polyethylene glycol (PEG side chains, can be cross-linked after injection by photopolymerization. The objective of this study was to investigate the use of this hydrogel, which allows tuning of its mechanical properties, as a scaffold for dental pulp tissue engineering. The cross-linking degree of PF hydrogels could be controlled by varying the amounts of PEG-diacrylate (PEG-DA cross-linker. PF hydrogels are generally cytocompatible with the encapsulated dental pulp stem cells (DPSCs, yielding >85% cell viability in all hydrogels. It was found that the cell morphology of encapsulated DPSCs, odontogenic gene expression, and mineralization were strongly modulated by the hydrogel cross-linking degree and matrix stiffness. Notably, DPSCs cultured within the highest cross-linked hydrogel remained mostly rounded in aggregates and demonstrated the greatest enhancement in odontogenic gene expression. Consistently, the highest degree of mineralization was observed in the highest cross-linked hydrogel. Collectively, our results indicate that PF hydrogels can be used as a scaffold for DPSCs and offers the possibility of influencing DPSCs in ways that may be beneficial for applications in regenerative endodontics.

  18. Modulation of Dental Pulp Stem Cell Odontogenesis in a Tunable PEG-Fibrinogen Hydrogel System

    Lu, Qiqi; Pandya, Mirali; Rufaihah, Abdul Jalil; Rosa, Vinicius; Tong, Huei Jinn; Seliktar, Dror; Toh, Wei Seong

    2015-01-01

    Injectable hydrogels have the great potential for clinical translation of dental pulp regeneration. A recently developed PEG-fibrinogen (PF) hydrogel, which comprises a bioactive fibrinogen backbone conjugated to polyethylene glycol (PEG) side chains, can be cross-linked after injection by photopolymerization. The objective of this study was to investigate the use of this hydrogel, which allows tuning of its mechanical properties, as a scaffold for dental pulp tissue engineering. The cross-linking degree of PF hydrogels could be controlled by varying the amounts of PEG-diacrylate (PEG-DA) cross-linker. PF hydrogels are generally cytocompatible with the encapsulated dental pulp stem cells (DPSCs), yielding >85% cell viability in all hydrogels. It was found that the cell morphology of encapsulated DPSCs, odontogenic gene expression, and mineralization were strongly modulated by the hydrogel cross-linking degree and matrix stiffness. Notably, DPSCs cultured within the highest cross-linked hydrogel remained mostly rounded in aggregates and demonstrated the greatest enhancement in odontogenic gene expression. Consistently, the highest degree of mineralization was observed in the highest cross-linked hydrogel. Collectively, our results indicate that PF hydrogels can be used as a scaffold for DPSCs and offers the possibility of influencing DPSCs in ways that may be beneficial for applications in regenerative endodontics. PMID:26124841

  19. Preparation and In Vitro Evaluation of a Stomach Specific Drug Delivery System based on Superporous Hydrogel Composite

    Chavda, H.V.; Patel, C. N.

    2011-01-01

    This study discusses efforts made to design drug-delivery system based on superporous hydrogel composite for sustained delivery of ranitidine hydrochloride. The characterization studies involve measurement of apparent density, porosity, swelling studies, mechanical strength studies, and scanning electron microscopy. Scanning electron microscopic images clearly showed the formation of interconnected pores, capillary channels, and the cross-linked sodium carboxymethylcellulose molecules around ...

  20. Oxidative stability of n-3 fatty acids encapsulated in filled hydrogel particles and of pork meat systems containing them.

    Salcedo-Sandoval, Lorena; Cofrades, Susana; Ruiz-Capillas, Claudia; Matalanis, Alison; McClements, D Julian; Decker, Eric A; Jiménez-Colmenero, Francisco

    2015-10-01

    The effect of storage time (2°C, 19 days) and heating (70°C, 30 min) on physical characteristics and oxidative stability of fish oil encapsulated in filled hydrogel particles was determined and compared with a conventional oil-in-water (O/W) emulsion with the same oil content (8.5%). Subsequently they were used to enrich meat systems with n-3 LCPUFAs, and their lipid oxidation was evaluated and compared with two other meat systems: one containing all animal fat and another with fish oil added directly. Filled hydrogel particles were more effective in lowering the oxidation rate than O/W emulsion, even when thermal treatment was applied. Oxidative stability over the storage time was best in the n-3 LCPUFA-enriched meat system containing filled hydrogel particles, in which TBARS levels were up to 62% lower than other systems containing fish oil. Hydrogel particles offer a promising means of controlling lipid oxidation in n-3 LCPUFA-enriched meat products. PMID:25872446

  1. Insulin Release Dynamics from Poly(diethylaminoethyl methacrylate) Hydrogel Systems.

    Marek, Steve R; Peppas, Nicholas A

    2013-10-01

    Novel glucose-sensitive systems for the release of insulin from poly(diethylaminoethyl methacrylate) (PDEAEM) micro-particles and nanoparticles decorated with glucose oxidase and catalase enzymes have been developed. The effect of polymer composition and loading conditions on the insulin loading efficiency and release was studied. The optimal conditions for loading insulin into PDEAEM microparticles were found to be at a loading pH of 5.6, particle to insulin mass ratio of 7:1, a concentration of 1.0 mg/mL insulin, and a collapsing pH of approximately 9.5. Microparticles exhibited a responsive (pH) or intelligent (glucose) release of insulin from a stimulus. Microparticles that had a nominal crosslinking ratio of 10% released a third of the insulin payload after a single stimulus, compared to nearly 70% for microparticles with a 3% crosslinking ratio. PDEAEM micro particles of 150 µm diameter showed promise as components of a system of automated, intelligent delivery method for insulin to type I diabetics. PMID:24634515

  2. Modulation of Dental Pulp Stem Cell Odontogenesis in a Tunable PEG-Fibrinogen Hydrogel System

    Qiqi Lu; Mirali Pandya; Abdul Jalil Rufaihah; Vinicius Rosa; Huei Jinn Tong; Dror Seliktar; Wei Seong Toh

    2015-01-01

    Injectable hydrogels have the great potential for clinical translation of dental pulp regeneration. A recently developed PEG-fibrinogen (PF) hydrogel, which comprises a bioactive fibrinogen backbone conjugated to polyethylene glycol (PEG) side chains, can be cross-linked after injection by photopolymerization. The objective of this study was to investigate the use of this hydrogel, which allows tuning of its mechanical properties, as a scaffold for dental pulp tissue engineering. The cross-li...

  3. Development and study of hydrogel-based microvalves for lab-on-a-chip systems

    Li, Ang

    2012-01-01

    Stimuli-responsive hydrogels such as poly(N-isopropylacrylamdie) (PNIPAAm) are excellent materials for microvalves due to their biocompatibility and high energy conversion efficiency. Hydrogel-based microvalves are simple to fabricate and operate compared to other actuation schemes. While many other hydrogel-based valves have been developed by other researchers, the valves presented here differ in the use of polymers as the basis for all microvalve components for increased flexibility. Thi...

  4. Emerging hydrogel designs for controlled protein delivery.

    Bae, Ki Hyun; Kurisawa, Motoichi

    2016-08-19

    Hydrogels have evolved into indispensable biomaterials in the fields of drug delivery and regenerative medicine. This minireview aims to highlight the recent advances in the hydrogel design for controlled release of bioactive proteins. The latest developments of enzyme-responsive and externally regulated drug delivery systems are summarized. The design strategies and applications of phase-separated hydrogel systems are also described. We expect that these emerging approaches will enable expanded use of hydrogels in biomedicine and healthcare. PMID:27374633

  5. Efficacy of amelogenin-chitosan hydrogel in biomimetic repair of human enamel in pH-cycling systems

    Ruan, Qichao; Liberman, David; Bapat, Rucha; Chandrababu, Karthik Balakrishna; Phark, Jin-Ho; Moradian-Oldak, Janet

    2016-01-01

    Amelogenin-chitosan (CS-AMEL) hydrogel has shown great potential for the prevention, restoration, and treatment of defective enamel. As a step prior to clinical trials, this study aimed to examine the efficacy of CS-AMEL hydrogel in biomimetic repair of human enamel with erosive or caries-like lesions in pH-cycling systems. Two models for enamel defects, erosion and early caries, were addressed in this study. Two pH-cycling systems were designed to simulate the daily cariogenic challenge as well as the nocturnal pH conditions in the oral cavity. After pH cycling and treatment with CS-AMEL hydrogel, a synthetic layer composed of oriented apatite crystals was formed on the eroded enamel surface. CS-AMEL repaired the artificial incipient caries by re-growing oriented crystals and reducing the depth of the lesions by up to 70% in the pH-cycling systems. The results clearly demonstrate that the CS-AMEL hydrogel is effective at the restoration of erosive and carious lesions under pH-cycling conditions. PMID:27331142

  6. Development of Bioadhesive Chitosan Superporous Hydrogel Composite Particles Based Intestinal Drug Delivery System

    Hitesh Chavda

    2013-01-01

    Full Text Available Bioadhesive superporous hydrogel composite (SPHC particles were developed for an intestinal delivery of metoprolol succinate and characterized for density, porosity, swelling, morphology, and bioadhesion studies. Chitosan and HPMC were used as bioadhesive and release retardant polymers, respectively. A 32 full factorial design was applied to optimize the concentration of chitosan and HPMC. The drug loaded bioadhesive SPHC particles were filled in capsule, and the capsule was coated with cellulose acetate phthalate and evaluated for drug content, in vitro drug release, and stability studies. To ascertain the drug release kinetics, the drug release profiles were fitted for mathematical models. The prepared system remains bioadhesive up to eight hours in intestine and showed Hixson-Crowell release with anomalous nonfickian type of drug transport. The application of SPHC polymer particles as a biomaterial carrier opens a new insight into bioadhesive drug delivery system and could be a future platform for other molecules for intestinal delivery.

  7. Three-dimensional hydrogel cell culture systems for modeling neural tissue

    Frampton, John

    Two-dimensional (2-D) neural cell culture systems have served as physiological models for understanding the cellular and molecular events that underlie responses to physical and chemical stimuli, control sensory and motor function, and lead to the development of neurological diseases. However, the development of three-dimensional (3-D) cell culture systems will be essential for the advancement of experimental research in a variety of fields including tissue engineering, chemical transport and delivery, cell growth, and cell-cell communication. In 3-D cell culture, cells are provided with an environment similar to tissue, in which they are surrounded on all sides by other cells, structural molecules and adhesion ligands. Cells grown in 3-D culture systems display morphologies and functions more similar to those observed in vivo, and can be cultured in such a way as to recapitulate the structural organization and biological properties of tissue. This thesis describes a hydrogel-based culture system, capable of supporting the growth and function of several neural cell types in 3-D. Alginate hydrogels were characterized in terms of their biomechanical and biochemical properties and were functionalized by covalent attachment of whole proteins and peptide epitopes. Methods were developed for rapid cross-linking of alginate hydrogels, thus permitting the incorporation of cells into 3-D scaffolds without adversely affecting cell viability or function. A variety of neural cell types were tested including astrocytes, microglia, and neurons. Cells remained viable and functional for longer than two weeks in culture and displayed process outgrowth in 3-D. Cell constructs were created that varied in cell density, type and organization, providing experimental flexibility for studying cell interactions and behavior. In one set of experiments, 3-D glial-endothelial cell co-cultures were used to model blood-brain barrier (BBB) structure and function. This co-culture system was

  8. Going beyond 2D: following membrane diffusion and topography in the IgE-Fc[epsilon]RI system using 3-dimensional tracking microscopy

    Wells, Nathan P [Los Alamos National Laboratory; Lessard, Guillaume A [Los Alamos National Laboratory; Phipps, Marry E [Los Alamos National Laboratory; Goodwin, Peter M [Los Alamos National Laboratory; Werner, James H [Los Alamos National Laboratory; Lidke, Diane S [UNM; Wilson, Bridget S [UNM

    2008-01-01

    The ability to follow and observe single molecules as they function in live cells would represent a major milestone for molecular-cellular biology. Here we present a tracking microscope that is able to track quantum dots in 3 dimensions and simultaneously record time-resolved emission statistics from a single dot. This innovative microscopy approach is based on four spatial filters and closed loop feedback to constantly keep a single quantum dot in the focal spot. Using this microscope, we demonstrate the ability to follow quantum dot-labeled IgE antibodies bound to Fc{epsilon}Rl membrane receptors in live RBL-2H3 cells. The results are consistent with prior studies of 2 dimensional membrane diffusion (Andrews et al., Nat. Cell Biol., 10, 955, 2008). In addition, the microscope captures motion in the axial (Z) direction, which permits tracking of diffusing receptors relative the 'hills and valley' of the dynamically changing membrane landscape. Our novel approach is uniquely capable of following single-molecule dynamics on live cells with 3 dimensional spatial resolution.

  9. Ultrahigh Resolution 3-Dimensional Imaging Project

    National Aeronautics and Space Administration — Southwest Sciences proposes to develop innovative instrumentation for the rapid, 3-dimensional imaging of biological tissues with cellular resolution. Our approach...

  10. Preparation of pH-sensitive poly(ethylene oxide) hydrogels grafted by γ-ray irradiation and their applications for drug delivery system

    Hydrogels are three-dimensional networks of hydrophilic polymers held together by crosslinks of covalent bonds or ionic bonds and secondary forces in the form of hydrogen bonds or hydrophobic interactions. Environmentally sensitive hydrogels have an enormous potential for various applications. Either pH-sensitive and/or temperature- sensitive hydrogels can be used for a site-specific controlled drug delivery. Especially, pH-sensitive hydrogels have been most frequently used to develop controlled release formulations for oral administration. All the pH-sensitive hydrogels contain pendent acidic, for example carboxylic and sulfonic acids, or basic, for example ammonium salts, groups that either accept or release protons in response to changes in environmental pH[3-5]. These ionic hydrogels are the swollen polymer networks which show sudden or gradual changes in their dynamic and equilibrium swelling behavior as a result of changing the external pH. In these gels, ionization occurs when the pH of the environment is above the pKa of the ionizable group . As the degree of ionization increases (pH increase in the system), the number of fixed charges increases, resulting in increased electrostatic repulsions between the chains. Irradiation, especially if combined with simultaneous sterilization of the product, is a very convenient tool for the synthesis of hydrogels. Radiation processing has many advantages over other conventional methods. For initiation processes, radiation differs from chemical initiation. In radiation processing, no catalysts or additives are needed to initiate the reaction. The advantages of the radiation methods are that they are relatively simple, and moreover, the degree of crosslinking, which strongly determines the extent of swelling in hydrogels, can be controlled easily by varying the absorbed dose. Therefore, these methods are found to be very useful in preparing hydrogels for medical applications, where even a small contamination is

  11. Teleportation of a 3-dimensional GHZ State

    Cao, Hai-Jing; Wang, Huai-Sheng; Li, Peng-Fei; Song, He-Shan

    2012-05-01

    The process of teleportation of a completely unknown 3-dimensional GHZ state is considered. Three maximally entangled 3-dimensional Bell states function as quantum channel in the scheme. This teleportation scheme can be directly generalized to teleport an unknown d-dimensional GHZ state.

  12. 3-dimensional Griess algebras and Miyamoto involutions

    lam, Ching Hung; Yamauchi, Hiroshi

    2016-01-01

    We consider a series of VOAs generated by 3-dimensional Griess algebras. We will show that these VOAs can be characterized by their 3-dimensional Griess algebras and their structures are uniquely determined. As an application, we will determine the groups generated by the Miyamoto involutions associated to Virasoro vectors of our VOAs.

  13. A drug delivery hydrogel system based on activin B for Parkinson's disease.

    Li, Juan; Darabi, Mohammadali; Gu, Jingjing; Shi, Junbin; Xue, Jinhua; Huang, Lu; Liu, Yutong; Zhang, Lei; Liu, N; Zhong, Wen; Zhang, Lin; Xing, Malcolm; Zhang, Lu

    2016-09-01

    Parkinson's disease (PD) is one of the most common neurodegenerative diseases. Activins are members of the superfamily of transforming growth factors and have many potential neuroprotective effects. Herein, at the first place, we verified activin B's neuroprotective role in a PD model, and revealed that activin B's fast release has limited function in the PD therapy. To this end, we developed a multi-functional crosslinker based thermosensitive injectable hydrogels to deliver activin B, and stereotactically injected the activin B-loaded hydrogel into the striatum of a mouse model of PD. The histological evaluation showed that activin B can be detected even 5 weeks post-surgery in PD mice implanted with activin B-loaded hydrogels, and activin B-loaded hydrogels can significantly increase the density of tyrosine hydroxylase positive (TH(+)) nerve fibers and reduce inflammatory responses. The behavioral evaluation demonstrated that activin B-loaded hydrogels significantly improved the performance of the mice in the PD model. Meanwhile, we found that hydrogels can slightly induce the activation of microglia cells and astrocytes, while cannot induce apoptosis in the striatum. Overall, our data demonstrated that the developed activin B-loaded hydrogels provide sustained release of activin B for over 5 weeks and contribute to substantial cellular protection and behavioral improvement, suggesting their potential as a therapeutic strategy for PD. PMID:27322960

  14. Delivery of interleukin-10 via injectable hydrogels improves renal outcomes and reduces systemic inflammation following ischemic acute kidney injury in mice.

    Soranno, Danielle E; Rodell, Christopher B; Altmann, Christopher; Duplantis, Jane; Andres-Hernando, Ana; Burdick, Jason A; Faubel, Sarah

    2016-08-01

    Injectable hydrogels can be used to deliver drugs in situ over a sustained period of time. We hypothesized that sustained delivery of interleukin-10 (IL-10) following acute kidney injury (AKI) would mitigate the local and systemic proinflammatory cascade induced by AKI and reduce subsequent fibrosis. Wild-type C57BL/6 mice underwent ischemia-reperfusion AKI with avertin anesthesia. Three days later, mice were treated with either hyaluronic acid injectable hydrogel with or without IL-10, or IL-10 suspended in saline, injected under the capsule of the left kidney, or hydrogel with IL-10 injected subcutaneously. Untreated AKI served as controls. Serial in vivo optical imaging tracked the location and degradation of the hydrogel over time. Kidney function was assessed serially. Animals were killed 28 days following AKI and the following were evaluated: serum IL-6, lung inflammation, urine neutrophil gelatinase-associated lipocalin, and renal histology for fibroblast activity, collagen type III deposition and fibrosis via Picrosirius Red staining and second harmonic imaging. Our model shows persistent systemic inflammation, and renal inflammation and fibrosis 28 days following AKI. The hydrogels are biocompatible and reduced serum IL-6 and renal collagen type III 28 days following AKI even when delivered without IL-10. Treatment with IL-10 reduced renal and systemic inflammation, regardless of whether the IL-10 was delivered in a sustained manner via the injectable hydrogel under the left kidney capsule, as a bolus injection via saline under the left kidney capsule, or via the injectable hydrogel subcutaneously. Injectable hydrogels are suitable for local drug delivery following renal injury, are biocompatible, and help mitigate local and systemic inflammation. PMID:26962109

  15. Swelling characteristics of hydroxyethylmethacrylate/ methacrylic acid pH -sensitive hydrogel as a drug delivery system

    M. Falamarzian- J. Varshosaz

    1996-01-01

    Hydroxyethyl methacrylate /methacrylic acid (HEMA/MAA) copolymer cross-linked with ethylenglycol dimethacrylate was prepared by a bulk.free radical polymerization method. The results indicate that this polymer is a pH -sensitive hydrogel which is collapsed in the acidic medium but completely swollen in the alkaline and neutral pH . it was determined that a proportion of 40% of MAA, the ionizing monomer of this hydrogel, was the best concentration among the different percentages used which sho...

  16. The synthesis of hydrogels with controlled distribution of polymer brushes in hydrogel network

    Sun, YuWei; Zhou, Chao; Zhang, AoKai; Xu, LiQun; Yao, Fang [School of Chemistry and Chemical Engineering, Southeast University, Jiangning District, Nanjing, Jiangsu Province, 211189 (China); Cen, Lian, E-mail: cenlian@hotmail.com [National Tissue Engineering Center of China, No.68, East Jiang Chuan Road, Shanghai, 200241 (China); School of Chemical Engineering, East China University of Science and Technology, No.130, Mei Long Road, Shanghai, 200237 (China); Fu, Guo-Dong, E-mail: fu7352@seu.edu.cn [School of Chemistry and Chemical Engineering, Southeast University, Jiangning District, Nanjing, Jiangsu Province, 211189 (China)

    2014-11-30

    Highlights: • Many biological tissues are 3-dimensionally asymmetric in structure and properties, it would be desirable if hydrogels could bear such structural similarity with specialized surface and bulk properties. Moreover, gradual but continuous variation in spatial structural and property is also a common phenomenon in biological tissues, such as interfaces between bone and tendon, or between bone and cartilage. Hence, the development of a method to introduce well-defined functional polymer brushes on PEG hydrogels, especially with precisely controlled spatial structure in 3-dimensions, would impart the hydrogels with special functionalities and wider applications. Poly(ethylene glycol) (PEG) hydrogels with 3-dimensionally controlled well-defined poly(N-isopropylacrylamide) (poly(NIPAAm)) brushes were prepared by combined copper(I)-catalyzed azide-alkyne cycloaddition (“Click Chemistry”) and atom transfer radical polymerization (ATRP). The resulting hydrogels were presented as representatives with their detailed synthesis routes and characterization. H{sub PEG}-S-poly(NIPAAm) is a hydrogel with poly(NIPAAm) brushes mainly grafted on surface, whereas H{sub PEG}-G-poly(NIPAAm) has a gradiently decreased poly(NIPAAm) brushes in their chain length from surface to inside. On the other hand, poly(NIPAAm) brushes in H{sub PEG}-U-poly(NIPAAm) are uniformly dispersed throughout the whole hydrogel network. Successful preparation of H{sub PEG}-S-poly(NIPAAm), H{sub PEG}-G-poly(NIPAAm) and H{sub PEG}-U-poly(NIPAAm) were ascertained by X-ray photoelectron spectroscopy (XPS) and water contact angle measurement. Hence, the flexibility and controllability of the synthetic strategy in varying the distribution of polymer brushes and hydrogel surface properties was demonstrated. Hydrogels with tunable and well-defined 3-dimensional poly(NIPAAm) polymer brushes could be tailor-designed to find potential applications in smart devices or skin dressing, such as for diabetics

  17. NIR and MR imaging supported hydrogel based delivery system for anti-TNF alpha probiotic therapy of IBD

    Janjic, Jelena M.; Berlec, Ales; Bagia, Christina; Liu, Lu S.; Jeric, Irenej; Gach, Michael; Janjic, Bratislav M.; Strukelj, Borut

    2016-03-01

    Current treatment of inflammatory bowel disease (IBD) is largely symptomatic and consists of anti-inflammatory agents, immune-suppressives or antibiotics, whereby local luminal action is preferred to minimize systemic side-effects. Recently, anti-TNFα therapy has shown considerable success and is now being routinely used. Here we present a novel approach of using perfluorocarbon (PFC) nanoemulsion containing hydrogels (nanoemulgels) as imaging supported delivery systems for anti-TNF alpha probiotic delivery in IBD. To further facilitate image-guided therapy a food-grade lactic acid bacterium Lactococcus lactis capable of TNFα-binding was engineered to incorporate infrared fluorescent protein (IRFP). This modified bacteria was then incorporated into novel PFC nanoemulgels. The nanoemulgels presented here are designed to deliver locally anti-TNFα probiotic in the lower colon and rectum and provide dual imaging signature of gel delivery (MRI) across the rectum and lower colon and bacteria release (NIR). NIR imaging data in vitro demonstrates high IRFP expressing and TNFα-binding bacteria loading in the hydrogel and complete release in 3 hours. Stability tests indicate that gels remain stable for at least 14 days showing no significant change in droplet size, zeta potential and pH. Flow cytometry analyses demonstrate the NIRF expressing bacteria L. lactis binds TNFα in vitro upon release from the gels. Magnetic resonance and near-infrared imaging in vitro demonstrates homogeneity of hydrogels and the imaging capacity of the overall formulation.

  18. 3-dimensional Oil Drift Simulations

    Wettre, C.; Reistad, M.; Hjøllo, B.Å.

    Simulation of oil drift has been an ongoing activity at the Norwegian Meteorological Institute since the 1970's. The Marine Forecasting Centre provides a 24-hour service for the Norwegian Pollution Control Authority and the oil companies operating in the Norwegian sector. The response time is 30 minutes. From 2002 the service is extended to simulation of oil drift from oil spills in deep water, using the DeepBlow model developed by SINTEF Applied Chemistry. The oil drift model can be applied both for instantaneous and continuous releases. The changes in the mass of oil and emulsion as a result of evaporation and emulsion are computed. For oil spill at deep water, hydrate formation and gas dissolution are taken into account. The properties of the oil depend on the oil type, and in the present version 64 different types of oil can be simulated. For accurate oil drift simulations it is important to have the best possible data on the atmospheric and oceanic conditions. The oil drift simulations at the Norwegian Meteorological Institute are always based on the most updated data from numerical models of the atmosphere and the ocean. The drift of the surface oil is computed from the vectorial sum of the surface current from the ocean model and the wave induced Stokes drift computed from wave energy spectra from the wave prediction model. In the new model the current distribution with depth is taken into account when calculating the drift of the dispersed oil droplets. Salinity and temperature profiles from the ocean model are needed in the DeepBlow model. The result of the oil drift simulations can be plotted on sea charts used for navigation, either as trajectory plots or particle plots showing the situation at a given time. The results can also be sent as data files to be included in the user's own GIS system.

  19. Controlled release of theophylline from poly(vinyl alcohol) hydrogels/porous silicon nanostructured systems

    Cervantes-Rincón, N.; Medellín-Rodríguez, F. J.; Escobar-Barrios, V. A.; Palestino, G.

    2013-03-01

    In this research, hybrid hydrogels of poly (vinyl alcohol)/ porous silicon (PSi)/theophylline were synthesized by the freezing and thawing method. We evaluated the influence of the synthesis parameters of the poly (vinyl alcohol) (PVA) hydrogels in relation to their ability to swell and drug released. The parameters studied (using an experimental design developed in Minitab 16) were the polymer concentration, the freezing temperature and the number of freezing/thawing (f/t) cycles. Nanostructured porous silicon particles (NsPSi) and theophylline were added within the polymer matrix to increase the drug charge and the polymer mechanical strength. The hybrid hydrogels were characterized by Infrared Spectroscopy Fourier Transform (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Differential Scanning Calorimetry (DSC), drug delivery kinetics were engineered according to the desired drug release schedule.

  20. Swelling characteristics of hydroxyethylmethacrylate/ methacrylic acid pH -sensitive hydrogel as a drug delivery system

    M. Falamarzian- J. Varshosaz

    1996-08-01

    Full Text Available Hydroxyethyl methacrylate /methacrylic acid (HEMA/MAA copolymer cross-linked with ethylenglycol dimethacrylate was prepared by a bulk.free radical polymerization method. The results indicate that this polymer is a pH -sensitive hydrogel which is collapsed in the acidic medium but completely swollen in the alkaline and neutral pH . it was determined that a proportion of 40% of MAA, the ionizing monomer of this hydrogel, was the best concentration among the different percentages used which showed a non-Fickian water transport mechanism. Increasing MAA content from 20 to 70% was accompanied with a change in water transport mechanism from Fickian to non-Fickian. However, increasing the percentage of MAA from 40 to 70 didn't improve the swelling capacity of this polymer. Pore size determination by a solute exclusion technique, showed the greatest distribution in the hydrogel with 40% MAA compared to other percentages of this monomer used. About 75% of the pores were less than 16.5 A in diameter in this polymer which is important specially in loading the hydrogel with macromoiecular drugs like proteines.

  1. Porous Hydrogels

    Přádný, Martin; Michálek, Jiří; Širc, Jakub

    New York: Nova Science Publishers, 2009 - (Acosta, J.; Camacho, A.), s. 57-74 ISBN 978-1-60741-401-8 R&D Projects: GA AV ČR 1QS400500558; GA MŠk 1M0538 Institutional research plan: CEZ:AV0Z40500505 Keywords : hydrogels * porous * tissue engineering Subject RIV: CD - Macromolecular Chemistry

  2. System Security Using 3-Dimensional Password

    B. B. Vikhe

    2015-11-01

    Full Text Available The purpose of this paper is increasing the safety house and avoiding the weakness of typical word. pc world surroundings authentication plays a vital role for word. User authentication is one amongst the foremost vital procedures needed to access secure and confidential information. Authentication of users is sometimes achieved through text-based passwords. Therefore researchers of recent days have gone for different strategies wherever in graphical image square measure used as a word. Image based mostly authentication permits user to form graphical word that has benefits over text-based passwords. Graphical passwords are designed to form passwords a lot of unforgettable and easier for folks to use. Persuasive Technology is employed to guide user’s alternative in click-based graphical passwords, exalting users to pick out a lot of random and therefore harder to guess click-points. during this paper, we've modified the method of clicking on the photographs and to form the word safer Advanced secret writing normal (AES technique is employed so authentication are often come safer and word will be generated, attested & protected simply. This Paper is enhance the safety, a user has got to decide a sequence for the photographs used throughout registration.

  3. Preparation and In vitro evaluation of a stomach specific drug delivery system based on superporous hydrogel composite

    H V Chavda

    2011-01-01

    Full Text Available This study discusses efforts made to design drug-delivery system based on superporous hydrogel composite for sustained delivery of ranitidine hydrochloride. The characterization studies involve measurement of apparent density, porosity, swelling studies, mechanical strength studies, and scanning electron microscopy. Scanning electron microscopic images clearly showed the formation of interconnected pores, capillary channels, and the cross-linked sodium carboxymethylcellulose molecules around the peripheries of pores. The prepared system floated and delivered the ranitidine hydrochloride for about 17 h. The release profile of ranitidine hydrochloride was studies by changing the retardant polymer in the system. To ascertain the drug release kinetics, the dissolution profiles were fitted to different mathematical models that include zero-order, first-order, Higuchi, Hixson-Crowell, Korsmeyer-Peppas, Weibull, and Hopfenberg models. The in vitro dissolution from system was explained by Korsmeyer-Peppas model. The diffusion exponent values in Korsmeyer-Peppas model range between 0.48±0.01 and 0.70±0.01, which appears to indicate an anomalous non-Fickian transport. It is concluded that the proposed mechanically stable floating drug-delivery system based on superporous hydrogel composite containing sodium carboxymethylcellulose as a composite material is promising for stomach specific delivery of ranitidine hydrochloride.

  4. Homological aperiodic tilings of 3-dimensional geometries

    Nowak, Piotr W

    2012-01-01

    We construct the first aperiodic tiles for two amenable 3-dimensional Lie groups: Sol and the Heisenberg group. Our construction relies on the use of higher-dimensional uniformly finite homology. In particular, we settle completely the existence of aperiodic tiles for all of the non-compact geometries of 3-manifolds appearing in the geometrization conjecture.

  5. Properties of 3-dimensional line location models

    Brimberg, Jack; Juel, Henrik; Schöbel, Anita

    2002-01-01

    We consider the problem of locating a line with respect to some existing facilities in 3-dimensional space, such that the sum of weighted distances between the line and the facilities is minimized. Measuring distance using the l\\_p norm is discussed, along with the special cases of Euclidean and...

  6. A study of chitosan hydrogel with embedded mesoporous silica nanoparticles loaded by ibuprofen as a dual stimuli-responsive drug release system for surface coating of titanium implants.

    Zhao, Pengkun; Liu, Hongyu; Deng, Hongbing; Xiao, Ling; Qin, Caiqin; Du, Yumin; Shi, Xiaowen

    2014-11-01

    In this study, the complex pH and electro responsive system made of chitosan hydrogel with embedded mesoporous silica nanoparticles (MSNs) was evaluated as a tunable drug release system. As a model drug, ibuprofen (IB) was used; its adsorption in MSNs was evidenced by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and thermogravimetric analysis (TG). In order to prepare the complex drug release system, the loaded particles IB-MSNs were dispersed in chitosan solution and then the complex IB-MSNs/chitosan film of 2mm thickness was deposited as a hydrogel on the titanium electrode. The codeposition of components was performed under a negative biasing of the titanium electrode at -0.75 mA/cm2 current density during 30 min. The IB release from the IB-MSNs/chitosan hydrogel film was studied as dependent on pH of the release media and electrical conditions applied to the titanium plate. When incubating the complex hydrogel film in buffers with different pH, the IB release followed a near zero-order profile, though its kinetics varied. Compared to the spontaneous IB release from the hydrogel in 0.9% NaCl solution (at 0 V), the application of negative biases to the coated titanium plate had profound effluences on the release behavior. The release was retarded when -1.0 V was applied, but a faster kinetics was observed at -5.0 V. These results imply that a rapid, mild and facile electrical process for covering titanium implants by complex IB-MSNs/chitosan hydrogel films can be used for controlled drug delivery applications. PMID:25456989

  7. 3-dimensional shaped aluminium foam sandwiches

    Baumeister, J. [Fraunhofer-Institut fuer Fertigungstechnik und Angewandte Materialforschung, Bremen (Germany); Baumgaertner, F. [Schunk Sintermetalltechnik, Giessen (Germany); Gers, H. [Honsel AG, Meschede (Germany); Seeliger, W. [Wilhelm Karmann GmbH, Osnabrueck (Germany)

    2000-07-01

    3-dimensional shaped sandwich panels with a very high stiffness can be produced in an elegant way by combining aluminium face sheets with an aluminium foam core. For this, a mixture of aluminium powder and a foaming agent is compressed to a semi-finished product of nearly vanishing porosity by extrusion, powder rolling or hot isostatic pressing. The resulting foamable semi-finished aluminium material is roll clad with sheets of conventional sheet or aluminium. As a result a precursor material is obtained consisting of two face sheets which are metallurgically bonded to the foamable core layer. This sandwich precursor material can be shaped into a 3-dimensional part by conventional techniques, e.g. by stamping or deep drawing. In a final step the foamable precursor material is heated up to the melting point of the core layer thus initiating its expansion into the desired 3-dimensional shaped sandwich structure. The porosity of the foamed core layer is in the range from 80-90% so that the integral density of the sandwich structure can be as low as 0,7 g/cm{sup 3}. The sandwich materials combine the low weight and high bending stiffness with the advantages of the face sheets, i.e. the high strength and weldability. The manufacturing process will be described in detail and the material properties will be shown. Current and future possible applications will be outlined as well as concrete parts produced up to date. (orig.)

  8. A Dendritic Thioester Hydrogel Based on Thiol-Thioester Exchange as a Dissolvable Sealant System for Wound Closure

    Ghobril, Cynthia; Charoen, Kristie; Rodriguez, Edward K.; Nazarian, Ara; Grinstaff, Mark W.

    2013-01-01

    A dissolvable dendritic thioester hydrogel based on thiol-thioester exchange for wound closure is reported. The hydrogel sealant adheres strongly to tissues, closes an ex vivo vein puncture, and withstands high pressures placed on a wound. The hydrogel sealant can be completely washed off upon exposure to thiolates based on thiol-thioester exchange and allow gradual wound re-exposure during definitive surgical care.

  9. Soy-Based Hydrogels for Biomedical Applications

    Soy based hydrogels were prepared by ring-opening polymerization of epoxidized soybean oil, flowing hydrolysis of formed polymer. The hydrogels were evaluated loading and release water-soluble anticancer drug doxorubin (Dox). The results suggested that this new system may offer great potential to ...

  10. A New Approach to 3-Dimensional Fields

    agashe, sadanand

    2016-01-01

    A new approach, using the operator "x d/dx + y d/dy + z d/dz", is introduced for studying 3-dimensional scalar and vector fields. The approach uses a property of the operator which is similar to that of the Laplacian operator, but the operator does not seem to have been used before. Also, the operator requires only once-differentiability of the fields. Using it, a number of new formulas are derived and new proofs given for many classical results such as the Helmholtz theorem, the Poisson form...

  11. 3-dimensional defect TQFTs and their tricategories

    Carqueville, Nils; Schaumann, Gregor

    2016-01-01

    We initiate a systematic study of 3-dimensional `defect' topological quantum field theories, that we introduce as symmetric monoidal functors on stratified and decorated bordisms. For every such functor we construct a tricategory with duals, which is the natural categorification of a pivotal bicategory. This captures the algebraic essence of defect TQFTs, and it gives precise meaning to the fusion of line and surface defects as well as their duality operations. As examples, we discuss how Reshetikhin-Turaev and Turaev-Viro theories embed into our framework, and how they can be extended to defect TQFTs.

  12. PRAGMATIC HYDROGELS

    Patil S.A.; Rane B.R.; Bakliwal S.R.; Pawar S.P.

    2011-01-01

    Man has always been plagued with many ailments and diseases. The field of pharmaceutical science has today become more invaluable in helping to keep us healthy and prevent disease. The availability of large molecular weight protein and peptide-based drugs due to the recent advances has given us a new ways to treat a number of diseases. I wish to present new and promising techniques for the production of drug and protein delivery formulations that have been developed that is Hydrogel. These ar...

  13. Orthogonal Enzymatic Reactions to Control Supramolecular Hydrogelations%Orthogonal Enzymatic Reactions to Control Supramolecular Hydrogelations

    陈国钦; 任春华; 王玲; 徐兵; 杨志谋

    2012-01-01

    Enzyme-responsive hydrogels have great potential in applications of controlled drug release, tissue engineering, etc. In this study, we reported on a supramolecular hydrogel that showed responses to two enzymes, phosphatase which was used to form the hydrogels and esterase which could trigger gelsol phase transitions. The gelation process and visco-elasticity property of the resulting gel, morphology of the nanostructures in hydrogel, and peptide conformation in the self-assembled nanostructure were characterized by theology, transmission electron microscope (TEM), and circular dichroism (CD), respectively. Potential application of the enzyme-responsive hydrogel in drug release was also demonstrated in this study. Though only one potential application of drug release was proved in this study, the responsive hydrogel system in this study might have potentials for the applications in fields of cell culture, controlled-drug release, etc.

  14. Synthesis and Characterization of Self-oscillating P(AA-co-AM)/PEG Semi-IPN Hydrogels Based on a pH Oscillator in Closed System

    Li-ping Wang; Jie Ren; Meng-qi Yao; Xiao-ci Yang; Wu Yang; Yan Li

    2014-01-01

    Various semi-interpenetrating polymer network (semi-IPN) hydrogels composed of pore-forming agent polyethylene glycol (PEG),acrylic acid (AA) and acrylamide (AM) were prepared by using free radical polymerization with a two-step method.The chemical structures of the synthesized hydrogels were characterized by FTIR spectroscopy and the morphologies were studied by scanning electron microscopy (SEM) method.The swelling properties,such as the pH-responsive behavior,salt sensitivity,oscillatory swelling/de-swelling behaviors in different solutions with various pH values and self-oscillating behaviors in bath pH oscillator were investigated in detail.The results revealed that the prepared hydrogels exhibited high pH sensitivity and excellent salt sensitivity when the pH values of the medium changes from 3.0 and 7.0 and well reversible properties by undergoing a number of swelling/de-swelling recycles.In particular,the hydrogels exhibited self-oscillation behavior in a closed system containing BrO3--SO32-Fe(CN)64-H+.This study may create a new possibility as biomaterial for new self-walking actuators and other devices.

  15. pH-Sensitive Hydrogel for Micro-Fluidic Valve

    Zhengzhi Yang

    2012-07-01

    Full Text Available The deformation behavior of a pH-sensitive hydrogel micro-fluidic valve system is investigated using inhomogeneous gel deformation theory, in which the fluid-structure interaction (FSI of the gel solid and fluid flow in the pipe is considered. We use a finite element method with a well adopted hydrogel constitutive equation, which is coded in commercial software, ABAQUS, to simulate the hydrogel valve swelling deformation, while FLUENT is adopted to model the fluid flow in the pipe of the hydrogel valve system. The study demonstrates that FSI significantly affects the gel swelling deformed shapes, fluid flow pressure and velocity patterns. FSI has to be considered in the study on fluid flow regulated by hydrogel microfluidic valve. The study provides a more accurate and adoptable model for future design of new pH-sensitive hydrogel valves, and also gives a useful guideline for further studies on hydrogel fluidic applications.

  16. Arct'Alg release from hydrogel membranes

    The hydrogel properties make them attractive for a variety of biomedical and pharmaceutical applications, primarily in drug delivery system. Synthetic hydrogels have been studied to develop new devices for drugs or cosmetic active agents release. Arct'AlgR is an extract derived from red algae biomass which has antioxidant, anti-inflammatory and tissue regeneration stimulant properties. This extract was incorporated to poly(N-vinyl pyrrolidone) (PVP) and poly(vinyl alcohol) (PVA) hydrogel membranes obtained by gamma rays crosslinking technique. The ionizing radiation presents the advantage to occur polymerization and sterilization simultaneously in the same process. The aim of this work was the in vitro release kinetic study of Arct'AlgR from hydrogel membranes during 24 hours to verify the possibility of use in cosmetic and dermatological treatments. Results showed that about 50% and 30% of incorporated Arct'AlgR was released from PVP and PVA hydrogel membrane devices respectively. (author)

  17. A dilogarithmic 3-dimensional Ising tetrahedron

    Broadhurst, D J

    1999-01-01

    In 3 dimensions, the Ising model is in the same universality class as unknown analytical nature. In contrast, all single-scale 4-dimensional tetrahedra were reduced, in hep-th/9803091, to special values of exponentially convergent polylogarithms. Combining dispersion relations with the integer-relation finder PSLQ, we find that $C^{Tet}/2^{5/2} = Cl_2(4\\alpha) - Cl_2(2\\alpha)$, with $Cl_2(\\theta):=\\sum_{n>0}\\sin(n\\theta)/n^2$ and 1,000-digit precision and readily yields 50,000 digits of $C^{Tet}$, after transformation to an exponentially convergent sum, akin to those studied in math.CA/9803067. It appears that this 3-dimensional result entails a polylogarithmic ladder beginning with the classical formula for $\\pi/\\sqrt2$, in the manner that 4-dimensional results build on that for $\\pi/\\sqrt3$.

  18. 3-dimensional bioprinting for tissue engineering applications.

    Gu, Bon Kang; Choi, Dong Jin; Park, Sang Jun; Kim, Min Sup; Kang, Chang Mo; Kim, Chun-Ho

    2016-01-01

    The 3-dimensional (3D) printing technologies, referred to as additive manufacturing (AM) or rapid prototyping (RP), have acquired reputation over the past few years for art, architectural modeling, lightweight machines, and tissue engineering applications. Among these applications, tissue engineering field using 3D printing has attracted the attention from many researchers. 3D bioprinting has an advantage in the manufacture of a scaffold for tissue engineering applications, because of rapid-fabrication, high-precision, and customized-production, etc. In this review, we will introduce the principles and the current state of the 3D bioprinting methods. Focusing on some of studies that are being current application for biomedical and tissue engineering fields using printed 3D scaffolds. PMID:27114828

  19. Biodegradable In Situ Gel-Forming Controlled Drug Delivery System Based on Thermosensitive Poly(ε-caprolactone)-Poly(ethylene glycol)-Poly(ε-caprolactone) Hydrogel

    Elham Khodaverdi; Ali Golmohammadian; Seyed Ahmad Mohajeri; Gholamhossein Zohuri; Farnaz Sadat Mirzazadeh Tekie; Farzin Hadizadeh

    2012-01-01

    Traditional drug delivery systems which are based on multiple dosing regimens usually pose many disadvantages such as poor compliance of patients and drug plasma level variation. To overcome the obstacles of traditional drug formulations, novel drug delivery system PCL-PEG-PCL hydrogels have been purposed in this study. Copolymers were synthesized by rapid microwave-assisted and conventional synthesis methods. Polymer characterizations were done using gel permeation chromatography and 1H-NMR....

  20. Performance Analysis of 3-Dimensional Turbo Codes

    Rosnes, Eirik

    2011-01-01

    In this work, we consider the minimum distance properties and convergence thresholds of 3-dimensional turbo codes (3D-TCs), recently introduced by Berrou et al.. Here, we consider binary 3D-TCs while the original work of Berrou et al. considered double-binary codes. In the first part of the paper, the minimum distance properties are analyzed from an ensemble perspective, both in the finite-length regime and in the asymptotic case of large block lengths. In particular, we analyze the asymptotic weight distribution of 3D-TCs and show numerically that their typical minimum distance dmin may, depending on the specific parameters, asymptotically grow linearly with the block length, i.e., the 3D-TC ensemble is asymptotically good for some parameters. In the second part of the paper, we derive some useful upper bounds on the dmin when using quadratic permutation polynomial (QPP) interleavers with a quadratic inverse. Furthermore, we give examples of interleaver lengths where an upper bound appears to be tight. The b...

  1. Cytocompatible Poly(ethylene glycol)-co-polycarbonate Hydrogels Crosslinked by Copper-free, Strain-promoted “Click” Chemistry

    Xu, Jianwen; Filion, Tera M.; Prifti, Fioleda; Song, Jie

    2011-01-01

    Strategies to encapsulate cells in cytocompatible 3-dimensional hydrogels with tunable mechanical properties and degradability without harmful gelling conditions are highly desired for regenerative medicine applications. Here we reported a method for preparing poly(ethylene glycol)-co-polycarbonate hydrogels through copper-free, strain-promoted azide-alkyne cycloaddition (SPAAC) “Click” chemistry. Hydrogels with varying mechanical properties were formed by “clicking” azido-functionalized poly...

  2. Skin Whitening and Anti-aging Effect of Fine Hydro-gel Cream Formulation with Botanical Oil Complex Using PIT Emulsifying System

    Hyun-Dae Cho1

    2014-01-01

    This study was to get unique formulation of multi-functional activity for preparing hydro-gel cream using PIT emulsifying system. In order to develop the good safety, adsorption and multi-functions, we made a new formulation using phase inversion temperature (PIT) containing 4 botanical oils such as camellia japonica seed oil, macadamia integrifolia seed oil, limnanthes alba (meadowfoam) seed oil, argania spinosa kernel oil, 0.04wt% of adenosine and 2wt% of niacinamide. The fi...

  3. In vitro and in vivo evaluation of a hydrogel-based prototype transdermal patch system of alfuzosin hydrochloride.

    Nair, Anroop B; Vaka, Siva Ram Kiran; Gupta, Sumit; Repka, Michael A; Murthy, S Narasimha

    2012-01-01

    The first-line therapy for moderate to severe benign prostatic hyperplasia is the oral therapy by alfuzosin hydrochloride. Unfortunately, the oral therapy of alfuzosin is associated with several route-specific systemic side-effects. The current study was aimed to develop a prototype transdermal patch system for alfuzosin using a hydrogel polymer and optimize the drug delivery through the skin for systemic therapy. The prospective of different chemical enhancers (polyethylene glycol (PEG 400), isopropyl myristate, propylene glycol, menthol and L-methionine; 5% w/v) and iontophoresis (0.3 mA/cm(2)) in the alfuzosin delivery across the full thickness rat skin was assessed in vitro. In vivo iontophoretic studies were carried out using selected patch system (PEG 400) for a period of 6 h in Sprague-Dawley rats. Passive permeation studies indicated that the incorporation of chemical agents have moderate effect (~4- to 7-fold) on the alfuzosin skin permeability and reduced the lag time. Combined approach of iontophoresis with chemical enhancers significantly augmented the drug transport (~ 43- to 72-fold). In vivo pharmacokinetic parameters revealed that the iontophoresis (transdermal patch with PEG 400) significantly enhanced the C(max) (~ 3-fold) and AUC(0-α) (~ 4-fold), when compared to control. The current study concludes that the application of iontophoresis (0.3 mA/cm(2)) using the newly developed agaorse-based prototype patch with PEG 400 could be utilized for the successful delivery of alfuzosin by transdermal route. PMID:20958130

  4. 3D modeling of human cancer: A PEG-fibrin hydrogel system to study the role of tumor microenvironment and recapitulate the in vivo effect of oncolytic adenovirus.

    Del Bufalo, Francesca; Manzo, Teresa; Hoyos, Valentina; Yagyu, Shigeki; Caruana, Ignazio; Jacot, Jeffrey; Benavides, Omar; Rosen, Daniel; Brenner, Malcolm K

    2016-04-01

    Interactions between malignant and stromal cells and the 3D spatial architecture of the tumor both substantially modify tumor behavior, including the responses to small molecule drugs and biological therapies. Conventional 2D culture systems cannot replicate this complexity. To overcome these limitations and more accurately model solid tumors, we developed a highly versatile 3D PEG-fibrin hydrogel model of human lung adenocarcinoma. Our model relevantly recapitulates the effect of oncolytic adenovirus; tumor responses in this setting nearly reproduce those observed in vivo. We have also validated the use of this model for complex, long-term, 3D cultures of cancer cells and their stroma (fibroblasts and endothelial cells). Both tumor proliferation and invasiveness were enhanced in the presence of stromal components. These results validate our 3D hydrogel model as a relevant platform to study cancer biology and tumor responses to biological treatments. PMID:26826297

  5. Cardiothoracic Applications of 3-dimensional Printing.

    Giannopoulos, Andreas A; Steigner, Michael L; George, Elizabeth; Barile, Maria; Hunsaker, Andetta R; Rybicki, Frank J; Mitsouras, Dimitris

    2016-09-01

    Medical 3-dimensional (3D) printing is emerging as a clinically relevant imaging tool in directing preoperative and intraoperative planning in many surgical specialties and will therefore likely lead to interdisciplinary collaboration between engineers, radiologists, and surgeons. Data from standard imaging modalities such as computed tomography, magnetic resonance imaging, echocardiography, and rotational angiography can be used to fabricate life-sized models of human anatomy and pathology, as well as patient-specific implants and surgical guides. Cardiovascular 3D-printed models can improve diagnosis and allow for advanced preoperative planning. The majority of applications reported involve congenital heart diseases and valvular and great vessels pathologies. Printed models are suitable for planning both surgical and minimally invasive procedures. Added value has been reported toward improving outcomes, minimizing perioperative risk, and developing new procedures such as transcatheter mitral valve replacements. Similarly, thoracic surgeons are using 3D printing to assess invasion of vital structures by tumors and to assist in diagnosis and treatment of upper and lower airway diseases. Anatomic models enable surgeons to assimilate information more quickly than image review, choose the optimal surgical approach, and achieve surgery in a shorter time. Patient-specific 3D-printed implants are beginning to appear and may have significant impact on cosmetic and life-saving procedures in the future. In summary, cardiothoracic 3D printing is rapidly evolving and may be a potential game-changer for surgeons. The imager who is equipped with the tools to apply this new imaging science to cardiothoracic care is thus ideally positioned to innovate in this new emerging imaging modality. PMID:27149367

  6. A novel gene delivery composite system based on biodegradable folate-poly (ester amine) polymer and thermosensitive hydrogel for sustained gene release

    Yang, Yi; Zhao, Hang; Jia, Yanpeng; Guo, Qingfa; Qu, Ying; Su, Jing; Lu, Xiaoling; Zhao, Yongxiang; Qian, Zhiyong

    2016-02-01

    Local anti-oncogene delivery providing high local concentration of gene, increasing antitumor effect and decreasing systemic side effects is currently attracting interest in cancer therapy. In this paper, a novel local sustained anti-oncogene delivery system, PECE thermoresponsive hydrogel containing folate-poly (ester amine) (FA-PEA) polymer/DNA (tumor suppressor) complexes, is demonstrated. First, a tumor-targeted biodegradable folate-poly (ester amine) (FA-PEA) polymer based on low-molecular-weight polyethyleneimine (PEI) was synthesized and characterized, and the application for targeted gene delivery was investigated. The polymer had slight cytotoxicity and high transfection efficiency in vitro compared with PEI 25k, which indicated that FA-PEA was a potential vector for targeted gene delivery. Meanwhile, we successfully prepared a thermoresponsive PECE hydrogel composite containing FA-PEA/DNA complexes which could contain the genes and slowly release the genes into cells. We concluded the folate-poly (ester amine) (FA-PEA) polymer would be useful for targeted gene delivery, and the novel gene delivery composite based on biodegradable folate-poly (ester amine) polymer and thermosensitive PECE hydrogel showed potential for sustained gene release.

  7. Hybrid hydrogels produced by ionizing radiation technique

    The interest in biocompatible hydrogels with particular properties has increased considerably in recent years due to their versatile applications in biomedicine, biotechnology, pharmacy, agriculture and controlled release of drugs. The use of hydrogels matrices for particular drug-release applications has been investigated with the synthesis of modified polymeric hydrogel of PVAl and 0.5, 1.0, 1.5% nano-clay. They were processed using gamma radiation from Cobalt-60 source at 25 kGy dose. The characterization of the hydrogels was conducted and toxicity was evaluated. The dried hydrogel was analyzed for thermogravimetry analysis (TGA), infrared spectroscopy (FTIR) and swelling in solutions of different pH. The membranes have no toxicity. The nano-clay influences directly the equilibrium swelling. - Highlights: ► Chemical interaction is observed when nanoclay is irradiated in PVAl hybrid hydrogels. ► Osmotic pressure within network promotes the rehydration capacity of the membranes. ► This effect is an important characteristic for hydrogels drug delivery systems.

  8. Digital microfluidic three-dimensional cell culture and chemical screening platform using alginate hydrogels.

    George, Subin M; Moon, Hyejin

    2015-03-01

    Electro wetting-on-dielectric (EWOD) digital microfluidics (DMF) can be used to develop improved chemical screening platforms using 3-dimensional (3D) cell culture. Alginate hydrogels are one common method by which a 3D cell culture environment is created. This paper presents a study of alginate gelation on EWOD DMF and investigates designs to obtain uniform alginate hydrogels that can be repeatedly addressed by any desired liquids. A design which allows for gels to be retained in place during liquid delivery and removal without using any physical barriers or hydrophilic patterning of substrates is presented. A proof of concept screening platform is demonstrated by examining the effects of different concentrations of a test chemical on 3D cells in alginate hydrogels. In addition, the temporal effects of the various chemical concentrations on different hydrogel posts are demonstrated, thereby establishing the benefits of an EWOD DMF 3D cell culture and chemical screening platform using alginate hydrogels. PMID:25945142

  9. Skin Whitening and Anti-aging Effect of Fine Hydro-gel Cream Formulation with Botanical Oil Complex Using PIT Emulsifying System

    Hyun-Dae Cho1

    2014-05-01

    Full Text Available This study was to get unique formulation of multi-functional activity for preparing hydro-gel cream using PIT emulsifying system. In order to develop the good safety, adsorption and multi-functions, we made a new formulation using phase inversion temperature (PIT containing 4 botanical oils such as camellia japonica seed oil, macadamia integrifolia seed oil, limnanthes alba (meadowfoam seed oil, argania spinosa kernel oil, 0.04wt% of adenosine and 2wt% of niacinamide. The fine botanical nutritive emulsion using PIT emulsifying method is easy absorbed into the stratum corneum because of fine droplet size. Appearance was high concentrated bluish liquid ulation was very safety to protect on the skin, major droplet was mean 105nm containing 20wt% of PIT botanical complex. And also, there are fine wrinkle improvement and whitening effect containing. Skin in-vivo evaluations carried out the efficacy and functions of hydro-gel cream such as moisturizing effect, TEWL, fine wrinkle improvement and whitening activity. This hydro-gel cream is to find an optimum way to enhance the strengthening effect on skin barrier functions of cosmetic formulations.

  10. Study of polymeric hydrogels with inorganic nanoparticles of clay

    Nanoscience has been applied in research of intelligent systems for drug delivery. The use of biodegradable synthetic polymers and in diagnostics and therapy has stimulated the application of nanotechnology in polymeric systems with new structures and new materials composing among these materials are hydrogels. Hydrogel with dispersed clay is a new class of materials that combine flexible and permeability of the hydrogels with the high efficiency of the clay to adsorb different substances. We evaluated the behaviour of swelling, gel fraction and thermal stability among the hydrogels obtained by poly (vinyl alcohol) (PVAl) with clay and poly (N-2-vinyl-pyrrolidone) (PVP) with clay. While, observed that the hydrogels showed swelling clay PVAl meaningful, the clay PVP hydrogels showed swelling more consistent after four hours of testing

  11. Elastic, Conductive, Polymeric Hydrogels and Sponges

    Yun Lu; Weina He; Tai Cao; Haitao Guo; Yongyi Zhang; Qingwen Li; Ziqiang Shao; Yulin Cui; Xuetong Zhang

    2014-01-01

    As a result of inherent rigidity of the conjugated macromolecular chains resulted from the delocalized π-electron system along the polymer backbone, it has been a huge challenge to make conducting polymer hydrogels elastic by far. Herein elastic and conductive polypyrrole hydrogels with only conducting polymer as the continuous phase have been simply synthesized in the indispensable conditions of 1) mixed solvent, 2) deficient oxidant, and 3) monthly secondary growth. The elastic mechanism an...

  12. 3-dimensional analysis of FELIX brick with hole

    Electromagnetic induction on FELIX brick with a hole has been analyzed with 3-Dimensional EDDYNET computer code. Incorporating loop currents on hexahedral meshes, the 3-Dimensional EDDYNET program solves eddy current problems by a network approach, and provides good accuracy even for coarse meshes. (author)

  13. Biomimetic hydrogel materials

    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.

  14. ADDITIVE-INDUCED ENHANCEMENT OF OPTICAL CLARITY OF POLYACRYLAMIDE HYDROGEL

    Jeffery Franklin; Zhi Yuan Wang

    2003-01-01

    The aqueous polymerization of acrylamide and crosslinking with N,N-methylenebisacrylamide afforded hydrogels displaying high levels of light scattering (poor optical clarity). Enhancement of the optical clarity within a polyacrylamide (PAm) hydrogel was accomplished through the implementation of"refractive index matching", Water-soluble additives were utilised to better match the refractive index inhomogeneities throughout a given hydrogel. This resulted in lower light scattering within the system and hence improved clarity. Amino acids, sugars, polymers, and other water-soluble additives such as glycerol were investigated by this methodology. Most additives investigated displayed potential for effectively reducing the light scattering within a PAm hydrogel as a function of increased additive concentration. On increasing the refractive index of the water medium, the overall refractive index of a PAm hydrogel was also observed to increase. This provided a quantitative means of determining the effectiveness of a given additive for improving the optical clarity within a hydrogel.

  15. PVA/atapulgite hydrogels

    PVA hydrogels can be used as wound-healing as a consequence of their biocompatibility, flexibility, etc. In order to improve mechanical resistance of wound-healing, polymeric hydrogels reinforced with clay have been studied. Among national clays, attapulgite stands out. Once it is a natural material, acid treatment can be required in order to remove impurities. In the present work, PVA hydrogels reinforced with attapulgite were produced and they were characterized by swelling behavior, XRD, DSC and traction test. Among all properties studied, hydrogels reinforced with activated attapulgite showed better mechanical resistance and Young module than the other samples. (author)

  16. Responsive Hydrogels for Label-Free Signal Transduction within Biosensors

    Kamila Gawel

    2010-04-01

    Full Text Available Hydrogels have found wide application in biosensors due to their versatile nature. This family of materials is applied in biosensing either to increase the loading capacity compared to two-dimensional surfaces, or to support biospecific hydrogel swelling occurring subsequent to specific recognition of an analyte. This review focuses on various principles underpinning the design of biospecific hydrogels acting through various molecular mechanisms in transducing the recognition event of label-free analytes. Towards this end, we describe several promising hydrogel systems that when combined with the appropriate readout platform and quantitative approach could lead to future real-life applications.

  17. Dual-functional transdermal drug delivery system with controllable drug loading based on thermosensitive poloxamer hydrogel for atopic dermatitis treatment

    Wang, Wenyi; Wat, Elaine; Hui, Patrick C. L.; Chan, Ben; Ng, Frency S. F.; Kan, Chi-Wai; Wang, Xiaowen; Hu, Huawen; Wong, Eric C. W.; Lau, Clara B. S.; Leung, Ping-Chung

    2016-04-01

    The treatment of atopic dermatitis (AD) has long been viewed as a problematic issue by the medical profession. Although a wide variety of complementary therapies have been introduced, they fail to combine the skin moisturizing and drug supply for AD patients. This study reports the development of a thermo-sensitive Poloxamer 407/Carboxymethyl cellulose sodium (P407/CMCs) composite hydrogel formulation with twin functions of moisture and drug supply for AD treatment. It was found that the presence of CMCs can appreciably improve the physical properties of P407 hydrogel, which makes it more suitable for tailored drug loading. The fabricated P407/CMCs composite hydrogel was also characterized in terms of surface morphology by field emission scanning electron microscopy (FE-SEM), rheological properties by a rheometer, release profile in vitro by dialysis method and cytotoxicity test. More importantly, the findings from transdermal drug delivery behavior revealed that P407/CMCs showed desirable percutaneous performance. Additionally, analysis of cytotoxicity test suggested that P407/CMCs composite hydrogel is a high-security therapy for clinical trials and thus exhibits a promising way to treat AD with skin moisturizing and medication.

  18. One-step synthesis of interpenetrating network hydrogels: Environment sensitivities and drug delivery properties

    Lu, Jingqiong; Li, Yinhui; Hu, Deng; Chen, Xiaoling; Liu, Yongmei; Wang, Liping; Ashraf, Muhammmad Aqeel; Zhao, Yansheng

    2015-01-01

    A novel interpenetrating network hydrogel for drug controlled release, composed of modified poly(aspartic acid) (KPAsp) and carboxymethyl chitosan (CMCTS), was prepared in aqueous system. The surface morphology and composition of hydrogels were characterized by SEM and FTIR. The swelling properties of KPAsp, KPAsp/CMCTS semi-IPN and KPAsp/CMCTS IPN hydrogels were investigated and the swelling dynamics of the hydrogels was analyzed based on the Fickian equation. The pH, temperature and salt se...

  19. Chemically cross-linked silk fibroin hydrogel with enhanced elastic properties, biodegradability, and biocompatibility

    Park, Won Ho

    2016-01-01

    Min Hee Kim, Won Ho Park Department of Advanced Organic Materials and Textile Engineering System, Chungnam National University, Daejeon, Korea Abstract: In this study, the synthesis of silk fibroin (SF) hydrogel via chemical cross-linking reactions of SF due to gamma-ray (γ-ray) irradiation was investigated, as were the resultant hydrogel’s properties. Two different hydrogels were investigated: physically cross-linked SF hydrogel and chemically cross-linked SF hydrogel i...

  20. Mechanical Behavior of Tough Hydrogels for Structural Applications

    Illeperuma, Widusha Ruwangi Kaushalya

    Hydrogels are widely used in many commercial products including Jell-O, contact lenses, and superabsorbent diapers. In recent decades, hydrogels have been under intense development for biomedical applications, such as scaffolds in tissue engineering, carriers for drug delivery, and valves in microfluidic systems. But the scope is severely limited as conventional hydrogels are weak and brittle and are not very stretchable. This thesis investigates the approaches that enhance the mechanical properties of hydrogels and their structural applications. We discov¬ered a class of exceptionally stretchable and tough hydrogels made from poly-mers that form networks via ionic and covalent crosslinks. Although such a hydrogel contains ~90% water, it can be stretched beyond 20 times its initial length, and has a fracture energy of ~9000 J/m2. The combination of large stretchability, remarkable toughness, and recoverability of stiffness and toughness, along with easy synthesis makes this material much superior over existing hydrogels. Extreme stretchability and blunted crack tips of these hydrogels question the validity of traditional fracture testing methods. We re-examine a widely used pure shear test method to measure the fracture energy. With the experimental and simulation results, we conclude that the pure shear test method can be used to measure fracture energy of extremely stretchable materials. Even though polyacrylamide-alginate hydrogels have an extremely high toughness, it has a relatively low stiffness and strength. We improved the stiffness and strength by embedding fibers. Most hydrogels are brittle, allowing the fibers to cut through the hydrogel when the composite is loaded. But tough hydrogel composites do not fail by the fibers cutting the hydrogel; instead, it undergoes large deforming by fibers sliding through the matrix. Hydrogels were not considered as materials for structural applications. But with enhanced mechanical properties, they have opened up

  1. l-Arginine grafted alginate hydrogel beads: A novel pH-sensitive system for specific protein delivery

    Mohamed S. Mohy Eldin

    2015-05-01

    Full Text Available Novel pH-sensitive hydrogels based on l-arginine grafted alginate (Arg-g-Alg hydrogel beads were synthesized and utilized as a new carrier for protein delivery (BSA in specific pH media. l-arginine was grafted onto the polysaccharide backbone of virgin alginate via amine functions. Evidences of grafting of alginate were extracted from FT-IR and thermal analysis, while the morphological structure of Arg-g-Alg hydrogel beads was investigated by SEM photographs. Factors affecting on the grafting process e.g. l-arginine concentration, reaction time, reaction temperature, reaction pH, and crosslinking conditions, have been studied. Whereas, grafting efficiency of each factor was evaluated. Grafting of alginate has improved both thermal and morphological properties of Arg-g-Alg hydrogel beads. The swelling behavior of Arg-g-Alg beads was determined as a function of pH and compared with virgin calcium alginate beads. The cumulative in vitro release profiles of BSA loaded beads were studied at different pHs for simulating the physiological environments of the gastrointestinal tract. The amount of BSA released from neat alginate beads at pH 2 was almost 15% after 5 h, while the Arg-g-Alg beads at the same conditions were clearly higher than 45%, then it increased to 90% at pH 7.2. Accordingly, grafting of alginate has improved its release profile behavior particularly in acidic media. The preliminary results clearly suggested that the Arg-g-Alg hydrogel may be a potential candidate for polymeric carrier for oral delivery of protein or drugs.

  2. New in situ crosslinking chemistries for hydrogelation

    Roberts, Meredith Colleen

    Over the last half century, hydrogels have found immense value as biomaterials in a vast number of biomedical and pharmaceutical applications. One subset of hydrogels receiving increased attention is in situ forming gels. Gelling by either bioresponsive self-assembly or mixing of binary crosslinking systems, these technologies are useful in minimally invasive applications as well as drug delivery systems in which the sol-to-gel transition aids the formulation's performance. Thus far, the field of in situ crosslinking hydrogels has received limited attention in the development of new crosslinking chemistries. Moreover, not only does the chemical nature of the crosslinking moieties allow these systems to perform in situ, but they contribute dramatically to the mechanical properties of the hydrogel networks. For example, reversible crosslinks with finite lifetimes generate dynamic viscoelastic gels with time-dependent properties, whereas irreversible crosslinks form highly elastic networks. The aim of this dissertation is to explore two new covalent chemistries for their ability to crosslink hydrogels in situ under physiological conditions. First, reversible phenylboronate-salicylhydroxamate crosslinking was implemented in a binary, multivalent polymeric system. These gels formed rapidly and generated hydrogel networks with frequency-dependent dynamic rheological properties. Analysis of the composition-structure-property relationships of these hydrogels---specifically considering the effects of pH, degree of polymer functionality, charge of the polymer backbone and polymer concentration on dynamic theological properties---was performed. These gels demonstrate diverse mechanical properties, due to adjustments in the binding equilibrium of the pH-sensitive crosslinks, and thus have the potential to perform in a range of dynamic or bioresponsive applications. Second, irreversible catalyst-free "click" chemistry was employed in the hydrogelation of multivalent azide

  3. Hydrogels Constructed from Engineered Proteins.

    Li, Hongbin; Kong, Na; Laver, Bryce; Liu, Junqiu

    2016-02-24

    Due to their various potential biomedical applications, hydrogels based on engineered proteins have attracted considerable interest. Benefitting from significant progress in recombinant DNA technology and protein engineering/design techniques, the field of protein hydrogels has made amazing progress. The latest progress of hydrogels constructed from engineered recombinant proteins are presented, mainly focused on biorecognition-driven physical hydrogels as well as chemically crosslinked hydrogels. The various bio-recognition based physical crosslinking strategies are discussed, as well as chemical crosslinking chemistries used to engineer protein hydrogels, and protein hydrogels' various biomedical applications. The future perspectives of this fast evolving field of biomaterials are also discussed. PMID:26707834

  4. Experiments with hydrogel pearls

    Pavlin, Jerneja

    2015-01-01

    Hydrogels are very attractive materials since they can absorb large quantities of water. They also have very interesting optical properties which can be easily shown. The experiments with hydrogel pearls related to the absorption of water, density, optical properties and influence of pH are presented in the contribution.

  5. Force-compensated hydrogel-based pH sensor

    Deng, Kangfa; Gerlach, Gerald; Guenther, Margarita

    2015-04-01

    This paper presents the design, simulation, assembly and testing of a force-compensated hydrogel-based pH sensor. In the conventional deflection method, a piezoresistive pressure sensor is used as a chemical-mechanical-electronic transducer to measure the volume change of a pH-sensitive hydrogel. In this compensation method, the pH-sensitive hydrogel keeps its volume constant during the whole measuring process, independent of applied pH value. In order to maintain a balanced state, an additional thermal actuator is integrated into the close-loop sensor system with higher precision and faster dynamic response. Poly (N-isopropylacrylamide) (PNIPAAm) with 5 mol% monomer 3-acrylamido propionic acid (AAmPA) is used as the temperature-sensitive hydrogel, while poly (vinyl alcohol) with poly (acrylic acid) (PAA) serves as the pH-sensitive hydrogel. A thermal simulation is introduced to assess the temperature distribution of the whole microsystem, especially the temperature influence on both hydrogels. Following tests are detailed to verify the working functions of a sensor based on pH-sensitive hydrogel and an actuator based on temperature-sensitive hydrogel. A miniaturized prototype is assembled and investigated in deionized water: the response time amounts to about 25 min, just half of that one of a sensor based on the conventional deflection method. The results confirm the applicability of t he compensation method to the hydrogel-based sensors.

  6. Ultrasound stimulated release of mimosa medicine from cellulose hydrogel matrix.

    Jiang, Huixin; Tovar-Carrillo, Karla; Kobayashi, Takaomi

    2016-09-01

    Ultrasound (US) drug release system using cellulose based hydrogel films was developed as triggered to mimosa. Here, the mimosa, a fascinating drug to cure injured skin, was employed as the loading drug in cellulose hydrogel films prepared with phase inversion method. The mimosa hydrogels were fabricated from dimethylacetamide (DMAc)/LiCl solution in the presence of mimosa, when the solution was exposed to ethanol vapor. The US triggered release of the mimosa from the hydrogel matrix was carried out under following conditions of US powers (0-30W) and frequencies (23, 43 and 96kHz) for different mimosa hydrogel matrix from 0.5wt% to 2wt% cellulose solution. To release the drug by US trigger from the matrix, the better medicine release was observed in the matrix prepared from the 0.5wt% cellulose solution when the 43kHz US was exposed to the aqueous solution with the hydrogel matrix. The release efficiency increased with the increase of the US power from 5 to 30W at 43kHz. Viscoelasticity of the hydrogel matrix showed that the hydrogel became somewhat rigid after the US exposure. FT-IR analysis of the mimosa hydrogel matrixes showed that during the US exposure, hydrogen bonds in the structure of mimosa-water and mimosa-cellulose were broken. This suggested that the enhancement of the mimosa release was caused by the US exposure. PMID:27150786

  7. Rapid Synthesis of Superabsorbent Smart-Swelling Bacterial Cellulose/Acrylamide-Based Hydrogels for Drug Delivery

    Manisha Pandey

    2013-01-01

    Full Text Available This study evaluated the effect of solubilized and dispersed bacterial cellulose (BC on the physicochemical characteristics and drug release profile of hydrogels synthesized using biopolymers. Superabsorbent hydrogels were synthesized by graft polymerization of acrylamide on BC solubilized in an NaOH/urea solvent system and on dispersed BC by using N,N′-methylenebisacrylamide as a crosslinker under microwave irradiation. Fourier transform infrared spectroscopy analysis of the resulting hydrogels confirmed the grafting, and an X-ray diffraction pattern showed a decrease in the crystallinity of BC after the grafting process. The hydrogels exhibited pH and ionic responsive swelling behavior, with hydrogels prepared using solubilized BC (SH having higher swelling ratios. Furthermore, compared to the hydrogels synthesized using dispersed BC, the hydrogels synthesized using solubilized BC showed higher porosity, drug loading efficiency, and release. These results suggest the superiority of the hydrogels prepared using solubilized BC and that they should be explored further for oral drug delivery.

  8. Fiber-reinforced tough hydrogels

    Illeperuma, Widusha Ruwangi Kaushalya; Sun, Jeong-Yun; Suo, Zhigang; Vlassak, Joost J.

    2014-01-01

    Using strong fibers to reinforce a hydrogel is highly desirable but difficult. Such a composite would combine the attributes of a solid that provides strength and a liquid that transports matter. Most hydrogels, however, are brittle, allowing the fibers to cut through the hydrogel when the composite is loaded. Here we circumvent this problem by using a recently developed tough hydrogel. We fabricate a composite using an alginate-polyacrylamide hydrogel reinforced with a random network of stai...

  9. 5-FU-hydrogel inhibits colorectal peritoneal carcinomatosis and tumor growth in mice

    Colorectal peritoneal carcinomatosis (CRPC) is a common form of systemic metastasis of intra-abdominal cancers. Intraperitoneal chemotherapy is a preferable option for colorectal cancer. Here we reported that a new system, 5-FU-loaded hydrogel system, can improve the therapeutic effects of intraperitoneal chemotherapy. A biodegradable PEG-PCL-PEG (PECE) triblock copolymer was successfully synthesized. The biodegradable and temperature sensitive hydrogel was developed to load 5-FU. Methylene blue-loaded hydrogel were also developed for visible observation of the drug release. The effects and toxicity of the 5-FU-hydrogel system were evaluated in a murine CRPC model. The hydrogel system is an injectable flowing solution at ambient temperature and forms a non-flowing gel depot at physiological temperature. 5-FU-hydrogel was subsequently injected into abdominal cavity in mice with CT26 cancer cells peritoneal dissemination. The results showed that the hydrogel delivery system prolonged the release of methylene blue; the 5-FU-hydrogel significantly inhibited the peritoneal dissemination and growth of CT26 cells. Furthermore, intraperitoneal administration of the 5-FU-hydrogel was well tolerated and showed less hematologic toxicity. Our data indicate that the 5-FU-hydrogel system can be considered as a new strategy for peritoneal carcinomatosis, and the hydrogel may provide a potential delivery system to load different chemotherapeutic drugs for peritoneal carcinomatosis of cancers

  10. Reinforcement of hydrogels using three-dimensionally printed microfibres

    Visser, Jetze; Melchels, Ferry P. W.; Jeon, June E.; van Bussel, Erik M.; Kimpton, Laura S.; Byrne, Helen M.; Dhert, Wouter J. A.; Dalton, Paul D.; Hutmacher, Dietmar W.; Malda, J

    2015-01-01

    Despite intensive research, hydrogels currently available for tissue repair in the musculoskeletal system are unable to meet the mechanical, as well as the biological, requirements for successful outcomes. Here we reinforce soft hydrogels with highly organized, high-porosity microfibre networks that

  11. 3DIVS: 3-Dimensional Immersive Virtual Sculpting

    Kuester, F; Duchaineau, M A; Hamann, B; Joy, K I; Uva, A E

    2001-10-03

    Virtual Environments (VEs) have the potential to revolutionize traditional product design by enabling the transition from conventional CAD to fully digital product development. The presented prototype system targets closing the ''digital gap'' as introduced by the need for physical models such as clay models or mockups in the traditional product design and evaluation cycle. We describe a design environment that provides an intuitive human-machine interface for the creation and manipulation of three-dimensional (3D) models in a semi-immersive design space, focusing on ease of use and increased productivity for both designer and CAD engineers.

  12. The 3-Dimensional q-Deformed Harmonic Oscillator and Magic Numbers of Alkali Metal Clusters

    Bonatsos, Dennis; Raychev, P P; Roussev, R P; Terziev, P A; Bonatsos, Dennis

    1999-01-01

    Magic numbers predicted by a 3-dimensional q-deformed harmonic oscillator with Uq(3) > SOq(3) symmetry are compared to experimental data for alkali metal clusters, as well as to theoretical predictions of jellium models, Woods--Saxon and wine bottle potentials, and to the classification scheme using the 3n+l pseudo quantum number. The 3-dimensional q-deformed harmonic oscillator correctly predicts all experimentally observed magic numbers up to 1500 (which is the expected limit of validity for theories based on the filling of electronic shells), thus indicating that Uq(3), which is a nonlinear extension of the U(3) symmetry of the spherical (3-dimensional isotropic) harmonic oscillator, is a good candidate for being the symmetry of systems of alkali metal clusters.

  13. PWR core safety analysis with 3-dimensional methods

    Highlights: • An overview of AREVA’s safety analysis codes their coupling is provided. • The validation base and licensing applications of these codes are summarized. • Coupled codes and methods provide improved margins and non-conservative results. • Examples for REA and inadvertent opening of the pressurizer safety valve are given. - Abstract: The main focus of safety analysis is to demonstrate the required safety level of the reactor core. Because of the demanding requirements, the quality of the safety analysis strongly affects the confidence in the operational safety of a reactor. To ensure the highest quality, it is essential that the methodology consists of appropriate analysis tools, an extensive validation base, and last but not least highly educated engineers applying the methodology. The sophisticated 3-dimensional core models applied by AREVA ensure that all physical effects relevant for safety are treated and the results are reliable and conservative. Presently AREVA employs SCIENCE, CASMO/NEMO and CASCADE-3D for pressurized water reactors. These codes are currently being consolidated into the next generation 3D code system ARCADIA®. AREVA continuously extends the validation base, including measurement campaigns in test facilities and comparisons of the predictions of steady state and transient measured data gathered from plants during many years of operation. Thus, the core models provide reliable and comprehensive results for a wide range of applications. For the application of these powerful tools, AREVA is taking benefit of its interdisciplinary know-how and international teamwork. Experienced engineers of different technical backgrounds are working together to ensure an appropriate interpretation of the calculation results, uncertainty analysis, along with continuously maintaining and enhancing the quality of the analysis methodologies. In this paper, an overview of AREVA’s broad application experience as well as the broad validation

  14. Thermosensitive chitosan-based hydrogel as a topical ocular drug delivery system of latanoprost for glaucoma treatment.

    Cheng, Yung-Hsin; Tsai, Tung-Hu; Jhan, Yong-Yu; Chiu, Allen Wen-Hsiang; Tsai, Kun-Ling; Chien, Chian-Shiu; Chiou, Shih-Hwa; Liu, Catherine Jui-Lin

    2016-06-25

    Ocular hypertension is a major risk factor for the development and progression of glaucoma. Frequent and long-term application of latanoprost often causes undesirable local side effects, which are a major cause of therapeutic failure due to loss of persistence in using this glaucoma medical therapy. In the present study, we developed a thermosensitive chitosan-based hydrogel as a topical eye drop formulation for the sustained release of latanoprost to control ocular hypertension. The developed formulation without preservatives may improve compliance and possibly even efficacy. The results of this study support its biocompatibility and sustained-release profile both in vitro and in vivo. After topical application of latanoprost-loaded hydrogel, triamcinolone acetonide-induced elevated intraocular pressure was significantly decreased within 7 days and remained at a normal level for the following 21 days in rabbit eyes. This newly developed chitosan-based hydrogel may provide a non-invasive alternative to traditional anti-glaucoma eye drops for glaucoma treatment. PMID:27083831

  15. A facile construction strategy of stable lipid nanoparticles for drug delivery using a hydrogel-thickened microemulsion system

    Chen Huabing; Xiao Ling; Du Danrong; Mou Dongsheng; Xu Huibi; Yang Xiangliang, E-mail: yangxl@mail.hust.edu.cn [College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2010-01-08

    We report a novel facile method for preparing stable nanoparticles with inner spherical solid spheres and an outer hydrogel matrix using a hot O/W hydrogel-thickened microemulsion with spontaneous stability. The nanoparticles with average diameters of about 30.0 nm and 100.0 nm were constructed by cooling the hot hydrogel-thickened microemulsion at different temperatures, respectively. We explained the application of these nanoparticles by actualizing the cutaneous delivery of drug-loaded nanoparticles. The in vitro skin permeation studies showed that the nanoparticles could significantly reduce the penetration of model drugs through skin and resulted in their dermal uptakes in skin. The sol-gel process of TEOS was furthermore used in the template of HTM to regulate the particle size of nanoparticles. The coating of silica on the surface of nanoparticles could regulate the penetration of drug into skin from dermal delivery to transdermal delivery. This strategy provides a facile method to produce nanoparticles with long-term stability and ease of manufacture, which might have a promising application in drug delivery.

  16. 3 dimensional volume MR imaging of intratemporal facial nerve

    Seo, Jeong Jin; Kang, Heoung Keun; Kim, Hyun Ju; Kim, Jae Kyu; Jung, Hyun Ung; Moon, Woong Jae [Chonnam University Medical School, Kwangju (Korea, Republic of)

    1994-10-15

    To evaluate the usefulness of 3 dimensional volume MR imaging technique for demonstrating the facial nerves and to describe MR findings in facial palsy patients and evaluate the significance of facial nerve enhancement. We reviewed the MR images of facial nerves obtained with 3 dimensional volume imaging technique before and after intravenous administration of Gadopentetate dimeglumine in 13 cases who had facial paralysis and 33 cases who had no facial palsy. And we analyzed the detectability of ananatomical segments of intratemporal facial nerves and facial nerve enhancement. When the 3 dimensional volume MR images of 46 nerves were analyzed subjectively, the nerve courses of 43(93%) of 46 nerves were effectively demonstrated on 3 dimensional volume MR images. Internal acoustic canal portions and geniculate ganglion of facial nerve were well visualized on axial images and tympanic and mastoid segments were well depicted on oblique sagittal images. 10 of 13 patients(77%) were visibly enhanced along at least one segment of the facial nerve with swelling or thickening, and nerves of 8 of normal 33 cases(24%) were enhanced without thickening or swelling. MR findings of facial nerve parelysis is asymmetrical thickening of facial nerve with contrast enhancement. The 3 dimensional volume MR imaging technique should be a useful study for the evaluation of intratemporal facial nerve disease.

  17. Hydrogel Actuation by Electric Field Driven Effects

    Morales, Daniel Humphrey

    Hydrogels are networks of crosslinked, hydrophilic polymers capable of absorbing and releasing large amounts of water while maintaining their structural integrity. Polyelectrolyte hydrogels are a subset of hydrogels that contain ionizable moieties, which render the network sensitive to the pH and the ionic strength of the media and provide mobile counterions, which impart conductivity. These networks are part of a class of "smart" material systems that can sense and adjust their shape in response to the external environment. Hence, the ability to program and modulate hydrogel shape change has great potential for novel biomaterial and soft robotics applications. We utilized electric field driven effects to manipulate the interaction of ions within polyelectrolyte hydrogels in order to induce controlled deformation and patterning. Additionally, electric fields can be used to promote the interactions of separate gel networks, as modular components, and particle assemblies within gel networks to develop new types of soft composite systems. First, we present and analyze a walking gel actuator comprised of cationic and anionic gel legs attached by electric field-promoted polyion complexation. We characterize the electro-osmotic response of the hydrogels as a function of charge density and external salt concentration. The gel walkers achieve unidirectional motion on flat elastomer substrates and exemplify a simple way to move and manipulate soft matter devices in aqueous solutions. An 'ionoprinting' technique is presented with the capability to topographically structure and actuate hydrated gels in two and three dimensions by locally patterning ions induced by electric fields. The bound charges change the local mechanical properties of the gel to induce relief patterns and evoke localized stress, causing rapid folding in air. The ionically patterned hydrogels exhibit programmable temporal and spatial shape transitions which can be tuned by the duration and/or strength of

  18. Development of sago starch hydrogel for wound dressing

    Sago starch is utilized in Malaysia mainly for food production. The purpose of the research is to diversify the use of sago starch for medical application particularly in development of hydrogel burn wound dressing. The sago starch is blending with mixture of PVP and PVA to improve the degree of crosslink, mechanical properties, swelling ability and tackiness of the blend hydrogel (sago/PVA and sago PVP). Additives have been introduced into the system such as, polypropylene glycol or carboxymethyl cellulose to improved further the swelling ability and tackiness properties of the blend hydrogel as well as other properties. Effect of irradiation dose on the blend hydrogel has also been studied to optimize the effective dose for blend hydrogel and simultaneously for sterilization purpose. (author)

  19. Development of sago starch hydrogel for wound dressing

    Kamaruddin Hashim; Khairul Zaman HJ. Mohd Dahlan; Kamarudin Bahari [Malaysian Institute for Nuclear Technology Research (MINT), Bangi (Malaysia); Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2001-03-01

    Sago starch is utilized in Malaysia mainly for food production. The purpose of the research is to diversify the use of sago starch for medical application particularly in development of hydrogel burn wound dressing. The sago starch is blending with mixture of PVP and PVA to improve the degree of crosslink, mechanical properties, swelling ability and tackiness of the blend hydrogel (sago/PVA and sago PVP). Additives have been introduced into the system such as, polypropylene glycol or carboxymethyl cellulose to improved further the swelling ability and tackiness properties of the blend hydrogel as well as other properties. Effect of irradiation dose on the blend hydrogel has also been studied to optimize the effective dose for blend hydrogel and simultaneously for sterilization purpose. (author)

  20. Arct'Alg release from hydrogel membranes

    Amaral, Renata H.; Rogero, Sizue O.; Shihomatsu, Helena M.; Lugao, Ademar B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], e-mail: rhamaral@ipen.br, e-mail: sorogero@ipen.br

    2009-07-01

    The hydrogel properties make them attractive for a variety of biomedical and pharmaceutical applications, primarily in drug delivery system. Synthetic hydrogels have been studied to develop new devices for drugs or cosmetic active agents release. Arct'Alg{sup R} is an extract derived from red algae biomass which has antioxidant, anti-inflammatory and tissue regeneration stimulant properties. This extract was incorporated to poly(N-vinyl pyrrolidone) (PVP) and poly(vinyl alcohol) (PVA) hydrogel membranes obtained by gamma rays crosslinking technique. The ionizing radiation presents the advantage to occur polymerization and sterilization simultaneously in the same process. The aim of this work was the in vitro release kinetic study of Arct'Alg{sup R} from hydrogel membranes during 24 hours to verify the possibility of use in cosmetic and dermatological treatments. Results showed that about 50% and 30% of incorporated Arct'Alg{sup R} was released from PVP and PVA hydrogel membrane devices respectively. (author)

  1. Engineered Polymeric Hydrogels for 3D Tissue Models

    Sujin Park

    2016-01-01

    Full Text Available Polymeric biomaterials are widely used in a wide range of biomedical applications due to their unique properties, such as biocompatibility, multi-tunability and easy fabrication. Specifically, polymeric hydrogel materials are extensively utilized as therapeutic implants and therapeutic vehicles for tissue regeneration and drug delivery systems. Recently, hydrogels have been developed as artificial cellular microenvironments because of the structural and physiological similarity to native extracellular matrices. With recent advances in hydrogel materials, many researchers are creating three-dimensional tissue models using engineered hydrogels and various cell sources, which is a promising platform for tissue regeneration, drug discovery, alternatives to animal models and the study of basic cell biology. In this review, we discuss how polymeric hydrogels are used to create engineered tissue constructs. Specifically, we focus on emerging technologies to generate advanced tissue models that precisely recapitulate complex native tissues in vivo.

  2. Hybrid Supramolecular and Colloidal Hydrogels that Bridge Multiple Length Scales**

    Janeček, Emma-Rose; McKee, Jason R; Tan, Cindy S Y; Nykänen, Antti; Kettunen, Marjo; Laine, Janne; Ikkala, Olli; Scherman, Oren A

    2015-01-01

    Hybrid nanocomposites were constructed based on colloidal nanofibrillar hydrogels with interpenetrating supramolecular hydrogels, displaying enhanced rheological yield strain and a synergistic improvement in storage modulus. The supramolecular hydrogel consists of naphthyl-functionalized hydroxyethyl cellulose and a cationic polystyrene derivative decorated with methylviologen moieties, physically cross-linked with cucurbit[8]uril macrocyclic hosts. Fast exchange kinetics within the supramolecular system are enabled by reversible cross-linking through the binding of the naphthyl and viologen guests. The colloidal hydrogel consists of nanofibrillated cellulose that combines a mechanically strong nanofiber skeleton with a lateral fibrillar diameter of a few nanometers. The two networks interact through hydroxyethyl cellulose adsorption to the nanofibrillated cellulose surfaces. This work shows methods to bridge the length scales of molecular and colloidal hybrid hydrogels, resulting in synergy between reinforcement and dynamics. PMID:25772264

  3. Hydrogels contact lenses

    Michálek, Jiří; Hobzová, Radka; Přádný, Martin; Dušková, Miroslava

    New York : Springer, 2010 - (Ottenbrite, R.; Park, K.; Okano, T.), s. 303-315 ISBN 978-1-4419-5918-8 R&D Projects: GA AV ČR KAN200520804 Institutional research plan: CEZ:AV0Z40500505 Keywords : contact lenses * hydrogels * silicone-hydrogels Subject RIV: EI - Biotechnology ; Bionics http://www.springerlink.com/content/l32kx3303v110unn/

  4. New antifouling silica hydrogel.

    Beltrán-Osuna, Ángela A; Cao, Bin; Cheng, Gang; Jana, Sadhan C; Espe, Matthew P; Lama, Bimala

    2012-06-26

    In this work, a new antifouling silica hydrogel was developed for potential biomedical applications. A zwitterionic polymer, poly(carboxybetaine methacrylate) (pCBMA), was produced via atom-transfer radical polymerization and was appended to the hydrogel network in a two-step acid-base-catalyzed sol-gel process. The pCBMA silica aerogels were obtained by drying the hydrogels under supercritical conditions using CO(2). To understand the effect of pCBMA on the gel structure, pCBMA silica aerogels with different pCBMA contents were characterized using scanning electron microscopy (SEM), nuclear magnetic resonance (NMR) spectroscopy, and the surface area from Brauner-Emmet-Teller (BET) measurements. The antifouling property of pCBMA silica hydrogel to resist protein (fibrinogen) adsorption was measured using enzyme-linked immunosorbent assay (ELISA). SEM images revealed that the particle size and porosity of the silica network decreased at low pCBMA content and increased at above 33 wt % of the polymer. The presence of pCBMA increased the surface area of the material by 91% at a polymer content of 25 wt %. NMR results confirmed that pCBMA was incorporated completely into the silica structure at a polymer content below 20 wt %. A protein adsorption test revealed a reduction in fibrinogen adsorption by 83% at 25 wt % pCBMA content in the hydrogel compared to the fibrinogen adsorption in the unmodified silica hydrogel. PMID:22607091

  5. Synthesis and Characterization of Super absorbent Hydrogels Based on Natural Polymers Using Ionizing Radiations

    Radiation processing technology is a useful tool for modification of polymer material including grafting of monomer onto polymer. In this study, novel super absorbent hydrogels was prepared with biodegradable and eco-friendly properties by graft copolymerization of chitosan and different synthetic monomers (AAc, DEAEMA, HEMA, HPMA and HEA) using gamma irradiation to examine the potential use of these hydrogels in the controlled drug release systems. The different chitosan hydrogels were characterized using FTIR spectroscopy, scanning electron microscopy and thermal analysis techniques. The effects of the preparation conditions on the gelation process of the synthesized copolymer were investigated. The influence of variables such as feed concentration, irradiation dose, composition ratio, ph and temperature on the swelling of the prepared hydrogels was also examined. The water absorbency of these hydrogels in various ph and salt solutions was studied. The swelling kinetics of the prepared hydrogels and in vitro release dynamics of model drug (Chlortetracycline hydrochloride) from these hydrogels has been studied for the evaluation of swelling mechanism and drug release mechanism from the hydrogels. The adsorption and in vitro release profiles of Chlortetracycline HCl from the prepared gels were also estimated in different ph buffers. The amount of drug released from CS/ (AAc-DEAEMA) hydrogels was higher than that released from other modified CS/AAc hydrogels. This preliminary investigation of chitosan based hydrogels showed that they may be exploited to expand the utilization of these systems in drug delivery applications

  6. Catalysis of Supramolecular Hydrogelation.

    Trausel, Fanny; Versluis, Frank; Maity, Chandan; Poolman, Jos M; Lovrak, Matija; van Esch, Jan H; Eelkema, Rienk

    2016-07-19

    One often thinks of catalysts as chemical tools to accelerate a reaction or to have a reaction run under more benign conditions. As such, catalysis has a role to play in the chemical industry and in lab scale synthesis that is not to be underestimated. Still, the role of catalysis in living systems (cells, organisms) is much more extensive, ranging from the formation and breakdown of small molecules and biopolymers to controlling signal transduction cascades and feedback processes, motility, and mechanical action. Such phenomena are only recently starting to receive attention in synthetic materials and chemical systems. "Smart" soft materials could find many important applications ranging from personalized therapeutics to soft robotics to name but a few. Until recently, approaches to control the properties of such materials were largely dominated by thermodynamics, for instance, looking at phase behavior and interaction strength. However, kinetics plays a large role in determining the behavior of such soft materials, for instance, in the formation of kinetically trapped (metastable) states or the dynamics of component exchange. As catalysts can change the rate of a chemical reaction, catalysis could be used to control the formation, dynamics, and fate of supramolecular structures when the molecules making up these structures contain chemical bonds whose formation or exchange are susceptible to catalysis. In this Account, we describe our efforts to use synthetic catalysts to control the properties of supramolecular hydrogels. Building on the concept of synthesizing the assembling molecule in the self-assembly medium from nonassembling precursors, we will introduce the use of catalysis to change the kinetics of assembler formation and thereby the properties of the resulting material. In particular, we will focus on the synthesis of supramolecular hydrogels where the use of a catalyst provides access to gel materials with vastly different appearance and mechanical

  7. Template-synthesized opal hydrogels

    LI Jun; JI Lijun; RONG Jianhua; YANG Zhenzhong

    2003-01-01

    Opal hydrogels could be synthesized with polymer inverse opal template. A pH responsive opal N-iso- propylacrylamide/acrylic acid copolymerized hydrogel was prepared as an example. The ordered structure and response to pH were investigated. Through the sol-gel process of tetrabutyl titanate, opal titania was obtained with the opal hydrogel template.

  8. Differential Cross Section Kinematics for 3-dimensional Transport Codes

    Norbury, John W.; Dick, Frank

    2008-01-01

    In support of the development of 3-dimensional transport codes, this paper derives the relevant relativistic particle kinematic theory. Formulas are given for invariant, spectral and angular distributions in both the lab (spacecraft) and center of momentum frames, for collisions involving 2, 3 and n - body final states.

  9. Controlled teleportation of a 3-dimensional bipartite quantum state

    Cao, Hai-Jing; Chen, Zhong-Hua; Song, He-Shan

    2008-07-01

    A controlled teleportation scheme of an unknown 3-dimensional (3D) two-particle quantum state is proposed, where a 3D Bell state and 3D GHZ state function as the quantum channel. This teleportation scheme can be directly generalized to teleport an unknown d-dimensional bipartite quantum state.

  10. Controlled teleportation of a 3-dimensional bipartite quantum state

    Cao Haijing; Chen Zhonghua [Physics Department, Shanghai University of Electric Power, Shanghai 201300 (China); Song Heshan [Physics Department, Dalian University of Technology, Dalian 116024 (China)], E-mail: 2007000084@shiep.edu.cn

    2008-07-15

    A controlled teleportation scheme of an unknown 3-dimensional (3D) two-particle quantum state is proposed, where a 3D Bell state and 3D GHZ state function as the quantum channel. This teleportation scheme can be directly generalized to teleport an unknown d-dimensional bipartite quantum state.

  11. 2 and 3-dimensional Hamiltonians with Shape Invariance Symmetry

    Jafarizadeh, M. A.; Panahi-Talemi, H.; Faizi, E.

    2000-01-01

    Via a special dimensional reduction, that is, Fourier transforming over one of the coordinates of Casimir operator of su(2) Lie algebra and 4-oscillator Hamiltonian, we have obtained 2 and 3 dimensional Hamiltonian with shape invariance symmetry. Using this symmetry we have obtained their eigenspectrum. In the mean time we show equivalence of shape invariance symmetry and Lie algebraic symmetry of these Hamiltonians.

  12. Ionically cross-linked alginate hydrogels as tissue engineering scaffolds

    Kuo, Catherine Kyleen

    Generation of living tissues through tissue engineering can be achieved via incorporation of cells into synthetic scaffolds designed to facilitate new tissue formation. Necessary characteristics of a scaffold include biocompatibility, high porosity with controllable pore size and interconnectivity, moldability, chemical and mechanical stability, and structural homogeneity. Hydrogels often possess many of the necessary characteristics and thus are favorable candidates for scaffolding. Alginate hydrogels are commonly made by ionically crosslinking with calcium ions from CaCl2 or CaSO4. These hydrogels are favored for their mild gel formation, however the gelation rate is rapid and uncontrollable (fast-gelation), resulting in varying crosslinking density throughout the gel. In this work, structurally homogeneous calcium alginate hydrogels were formed via a slow-gelation system that utilizes uniform mixing of CaCO3 with sodium alginate solution, and the addition of slowly hydrolyzing D-gluconic acid lactone to slowly release calcium ions for crosslinking. Homogeneity and mechanical properties of these hydrogels were shown to be superior to those of fast-gelled hydrogels. Gelation rate was controlled through the incorporation of CaSO4, and by varying total calcium content, polymer concentration and gelation temperature. Control over mechanical properties and diffusivity was demonstrated in the homogeneous hydrogels by adjusting compositional variables. Consistent control over solute diffusivity through gel discs reflected the structural homogeneity of the gels. To overcome the instability of ionically crosslinked gels in tissue culture medium, a method was developed to control the hydrogel dimensions by adjusting the ionic concentration of the medium. Stability of the hydrogels in this controlled environment was characterized through swelling experiments and mechanical testing. To provide for scaffold degradation and thereby promote tissue growth, alginate lyase was

  13. New double-walled PH-sensitive hydrogel systems containing nanoparticle drug for colon-specific drug delivery

    Double-walled (DW) with a Core of mixture of nano or microparticles of carboxymethyl cellulose sodium (CMC) salt and model drug olsalazine [3, 3-azobis (6-hydroxy benzoic acid)] (OSZ) as an azo derivatives of 5-aminosalicylic acid (5-ASA) and an external coat of cross-linked copolymers of (acrylamido methyl) cellulose acetate butyrate (AMCAB) and methacrylic acid (MAA) with various amounts of 1, 6-hexandiol diacrylate (HDD) are considered cross-linking agents (CA). The core with nano composite was prepared by freeze drying method and then used as nuclei for subsequent shell copolymerization. The structure of core was characterized with scanning electron microscopy. The double-walled hydrogels were characterized by differential scanning colorimetry and FT-IR. Studies of drug release were carried out in enzyme-free , simulated gastric and intestinal fluids (SGF and SIF, respectively). The drug-release profiles indicated that the amount of drug released depended ed on the shell layer composition. The releasing was modulated by the amount of cross-linking in shell layer. Bused on the great difference in hydrolysis rates at pH 1 and 7.4, these pH-sensitive hydrogels appear to be good candidates, for colon-specific drug delivery

  14. A three-phase in-vitro system for studying Pseudomonas aeruginosa adhesion and biofilm formation upon hydrogel contact lenses

    Kohlmann Thomas

    2010-11-01

    Full Text Available Abstract Background Pseudomonas aeruginosa is commonly associated with contact lens (CL -related eye infections, for which bacterial adhesion and biofilm formation upon hydrogel CLs is a specific risk factor. Whilst P. aeruginosa has been widely used as a model organism for initial biofilm formation on CLs, in-vitro models that closely reproduce in-vivo conditions have rarely been presented. Results In the current investigation, a novel in-vitro biofilm model for studying the adherence of P. aeruginosa to hydrogel CLs was established. Nutritional and interfacial conditions similar to those in the eye of a CL wearer were created through the involvement of a solid:liquid and a solid:air interface, shear forces and a complex artificial tear fluid. Bioburdens varied depending on the CL material and biofilm maturation occurred after 72 h incubation. Whilst a range of biofilm morphologies were visualised including dispersed and adherent bacterial cells, aggregates and colonies embedded in extracellular polymer substances (EPS, EPS fibres, mushroom-like formations, and crystalline structures, a compact and heterogeneous biofilm morphology predominated on all CL materials. Conclusions In order to better understand the process of biofilm formation on CLs and to test the efficacy of CL care solutions, representative in-vitro biofilm models are required. Here, we present a three-phase biofilm model that simulates the environment in the eye of a CL wearer and thus generates biofilms which resemble those commonly observed in-situ.

  15. Rheological Characterization of Bioinspired Mineralization in Hydrogels

    Regitsky, Abigail; Holten-Andersen, Niels

    With increasing amounts of CO2 in the atmosphere linked to potentially catastrophic climate change, it is critical that we find methods to permanently sequester and store CO2. Inspired by the natural biomineralization of calcium carbonate (CaCO3), one future goal of this project is to understand the mechanisms of CaCO3 mineralization in order to ultimately optimize a bioinspired hydrogel system, which produces high value industrial powders that consume CO2 as a feedstock. Along the way, we are developing a rheological technique to study mineral nucleation and growth events by measuring the modulations in mechanical properties of a hydrogel system during mineralization. Our initial system consists of a gelatin hydrogel matrix, which is preloaded with calcium ions, and an aqueous solution of carbonate ions, which are allowed to diffuse through the gel to initiate the mineralization process. In order to monitor how the growth of minerals affects the mechanical properties of the gel network, we measure the storage (G') and loss (G'') moduli of the system in situ. Future work will focus on modifying the properties of the minerals formed by changing the polymer used in the hydrogel network and adding other organic molecules into the system.

  16. Clinical advantage and limitation of the 3-dimensional magnetic resonance imaging of the brain

    The authors discuss practical techniques of 3-dimensional magnetic resonance images. Raw data for 3-dimensional MRI were acquired using a 3D turbo-FLASH sequence. The data were processed in the following three ways; 1) volume rendering of all the raw data, 2) segmentation of the brain from other tissue using other software and the volume rendering of all the raw data, and 3) reconstruction of 2-dimensional image of the arbitrary orientation (oblique-oblique and curvature) using multi-planar reconstruction (MPR). In addition to these basic techniques, a surgical window technique, maximum intensity projection (MIP), and skin marking using fatty acid gel in capsules can provide the following unique images; 1) surface images of the skin, skull and brain, 2) images of the arteries and the main cortical vein superimposed on the brain-surface images, and 3) surgical images simulating craniotomy. The drawbacks of 3-dimensional MRI at present are twofold; 1)it requires mini-computers, which is not always available at every clinical site, and 2) the time necessary for data processing and image reconstruction depends on the performance of the computer, but in any case the segmentation of the brain from other soft tissue is a time-consuming job, one which generally takes several hours. However, it is expected that these present limitations of 3-dimentional MRI are only temporary because fast and high cost-performance computers for this specific purpose (image processing) have recently become available. The authors stress that the most important factor which drives the development of a high cost-performance system for 3-dimensional MRI is the demand from clinicians, who realize the advantages of 3-dimensional MRI. (author)

  17. Sequential release of salidroside and paeonol from a nanosphere-hydrogel system inhibits ultraviolet B-induced melanogenesis in guinea pig skin

    Peng LH

    2014-04-01

    Full Text Available Li-Hua Peng,1 Shen-Yao Xu,1 Ying-Hui Shan,1 Wei Wei,1 Shuai Liu,1 Chen-Zhen Zhang,1 Jia-He Wu,1 Wen-Quan Liang,1 Jian-Qing Gao1,2 1Institute of Pharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 2Novel Transdermal Research Center of Jiangsu Province, Changzhou, People's Republic of China Abstract: Melanin is the one of most important pigments for skin color in mammals. Excessive biosynthesis of melanin induces various pigment disorders. Much effort has been made to develop regulators to minimize skin pigmentation abnormalities. However, only a few of them are used, primarily because of safety concerns and low efficiency. In this study, we aimed to construct a novel nanosphere-gel for sequential delivery of salidroside and paeonol, to investigate the synergistic effects of these drugs in anti-melanogenesis, and to decrease their potential for toxicity in high dosage. Nanospheres were prepared and characterized for their particle size, polydispersity index, zeta potential, and morphological properties. The optimized nanospheres were incorporated in carbomer hydrogel with both paeonol and salidroside entrapped to form a dual drug-releasing nanosphere-gel. With this nanosphere-gel, rapid release of salidroside from the hydrogel followed by sustained release of paeonol from the nanosphere was achieved. Using a classical model of the melanogenesis response to ultraviolet exposure, it was shown that the anti-melanogenesis effects of the dual drug-releasing system, in which the doses of the individual drugs were decreased by half, was obviously enhanced when compared with the effects of the single drug preparations. Mechanistically, the burst release of salidroside from the hydrogel may enable prompt suppression of melanocyte proliferation on exposure to ultraviolet B radiation, while the paeonol released in a sustained manner can provide continuous inhibition of tyrosinase activity in melanocytes. Combined delivery of

  18. Radio-synthesized polyacrylamide hydrogels for proteins release

    The use of hydrogels for biomedical purposes has been extensively investigated. Pharmaceutical proteins correspond to highly active substances which may be applied for distinct purposes. This work concerns the development of radio-synthesized hydrogel for protein release, using papain and bovine serum albumin as model proteins. The polymer was solubilized (1% w/v) in water and lyophilized. The proteins were incorporated into the lyophilized polymer and the hydrogels were produced by simultaneous crosslinking and sterilization using γ-radiation under frozen conditions. The produced systems were characterized in terms of swelling degree, gel fraction, crosslinking density and evaluated according to protein release, bioactivity and cytotoxicity. The hydrogels developed presented different properties as a function of polymer concentration and the optimized results were found for the samples containing 4–5% (w/v) polyacrylamide. Protein release was controlled by the electrostatic affinity of acrylic moieties and proteins. This selection was based on the release of the proteins during the experiment period (up to 50 h), maintenance of enzyme activity and the nanostructure developed. The system was suitable for protein loading and release and according to the cytotoxic assay it was also adequate for biomedical purposes, however this method was not able to generate a matrix with controlled pore sizes. Highlights: • Method for synthesis of polyacrylamide (copolymer) hydrogels using γ-irradiation. • Polyacrylamide hydrogels suitable for protein loading and release. • Controlled release of proteins and bioactivity maintenance. • Noncytotoxic profile observed for these protein containing hydrogels

  19. pH-Sensitive Hydrogel for Micro-Fluidic Valve

    Zhengzhi Yang; Haiyan Miao; Zhiwei Ding; Somsak Swaddiwudhipong; Yan Zhang; Zishun Liu

    2012-01-01

    The deformation behavior of a pH-sensitive hydrogel micro-fluidic valve system is investigated using inhomogeneous gel deformation theory, in which the fluid-structure interaction (FSI) of the gel solid and fluid flow in the pipe is considered. We use a finite element method with a well adopted hydrogel constitutive equation, which is coded in commercial software, ABAQUS, to simulate the hydrogel valve swelling deformation, while FLUENT is adopted to model the fluid flow in the pipe of the hy...

  20. The application of 3-dimensional CAT scan reconstruction for maxillofacial deformities

    It has been found very useful to recognize craniofacial deformities 3-dimensionally, and to observe 3-D Cat scan reconstructions that have been performed by others. Thus, starting in 1985, we have developed a 3-D CT system that combines conventional X-ray CAT scan hardware to a 3-Dimensional display software. In this paper we report on our 3-CT system, its basic algorithm, and its basic processes, i.e., the threshold process, the perspective process, the shading process and the display. The mixture shading which we have developed makes 3-D displays clearer and more natural. Also, we have applied our 3-D display to 39 cases of maxillofacial diformities. (author)

  1. 基于Kinect的移动机器人大视角3维V-SLAM%A Large Viewing Angle 3-Dimensional V-SLAM Algorithm with a Kinect-based Mobile Robot System

    辛菁; 苟蛟龙; 马晓敏; 黄凯; 刘丁; 张友民

    2014-01-01

    To solve the performance degradation problem of the mobile robot 3D V-SLAM (visual simultaneous local-ization and mapping) in the presence of large viewing angle, an affine invariant features matching algorithm AORB (affine oriented FAST and rotated BRIEF) is proposed, and a mobile robot large viewing angle 3D V-SLAM system using Kinect camera is further developed. Firstly, AORB algorithm is adopted to implement the fast and efficient matching between ad-jacent frames captured by the Kinect RGB camera in the presence of large changes of viewing angle, and the corresponding relationship between adjacent frames is created. Secondly, 2D image points are converted into 3D color cloud data through using the calibrated intrinsic and extrinsic parameters of Kinect, and pixel depth values after alignment correction. Thirdly, the relative pose between adjacent frames is computed by using the least-squares algorithm after removing outliers using RANSAC (RANdom Sample Consensus). Finally, the 3D model is obtained by optimizing the resulting pose using g2o (gen-eral graph optimization). Mobile robot large viewing angle 3D V-SLAM is realized ultimately. Both the off-line (based on well-known and available benchmark data sets) and the online (with a developed mobile robot system) experimental testing show that the proposed matching algorithm and the developed 3D V-SLAM system can accurately update the local model, successfully reconstruct the environment model, and effectively estimate the motion trajectory of the mobile robot in the presence of large viewing angle.%针对大视角情况下,移动机器人3维视觉同步定位与地图构建(visual simultaneous localization and mapping,V-SLAM)性能下降的问题,提出了一种仿射不变特征匹配算法AORB(affine oriented FAST and rotated BRIEF)并在此基础上构建了基于Kinect的移动机器人大视角3D V-SLAM系统.首先对Kinect相机采集到的彩色RGB数据采用AORB算法实现具有大

  2. The influence of biological motifs and dynamic mechanical stimulation in hydrogel scaffold systems on the phenotype of chondrocytes.

    Appelman, Taly P; Mizrahi, Joseph; Elisseeff, Jennifer H; Seliktar, Dror

    2011-02-01

    Primary bovine chondrocytes and PEG-based hydrogels were used to investigate the effects of scaffold composition and architecture on the cellular response to large dynamic compressive strain stimulation. Proteins and proteoglycans were conjugated to functionalized poly(ethylene glycol) (PEG) and immobilized in PEG hydrogels to create bio-synthetic scaffolds. Second passage articular chondrocytes were encapsulated into four different scaffold compositions: PEG-Proteoglycan (PP), PEG-Fibrinogen (PF), PEG-Albumin (PA), and PEG only and subjected to 15% dynamic compressive strain at 1-Hz frequency. Cellular response was evaluated in terms of cell number, glycosaminoglycans (GAGs), collagen type II and collagen type I accumulation in the constructs following 24h and 28 days of stimulated and static culture. Stimulation of the constructs resulted in an increase in the cell number in all scaffolds, with no statistical difference measured among them. Dynamic stimulation of PP, PF, PA and PEG constructs resulted in a respective increase in the GAGs by 33%, 53.4%, 240.5%, and 284.5%, compared to their static controls. The permissive PEG and PA scaffolds showed a significantly larger relative increase in the GAGs in comparison to the other scaffolds tested. Collagen type II content in the PF, PA and PEG constructs increased by 78%, 1266% and 896% respectively, compared to their static controls. Permissive constructs showed a significantly larger relative increase and final absolute values of GAGs and type II collagen, compared to the PF constructs. Immunostaining for collagen type I, an indicator for chondrocyte de-differentiation, indicated that stimulation inhibited its production. Correlation maps between scaffold properties highlighted the major differences between permissive and instructive scaffolds. These results support the hypothesis that both compressive strain and scaffold bioactivity have an important effect on the chondrocyte metabolic response to mechanical

  3. Nanoparticle diffusometry in hydrogels

    Kort, de, YAW Yvonne

    2016-01-01

    In order to understand food product functionality such as elastic and flow behavior and mass transport properties, one first has to understand the multi-length-scale structure of the material. The aim of this work is to explore novel methodologies to study and characterize multi-length-scale structures of food hydrogels under static and dynamic conditions. The focus lies on hydrogels comprising polysaccharides, because they show a rich variation in elastic and flow behavior. The largest part of ...

  4. 3-Dimensional reconstruction of fluorescent structures in tardigrades

    Franz BRÜMMER

    2007-09-01

    Full Text Available Tardigrades are microscopic animals, thus brightfield microscopy is a well established method for tardigrade observation. Modern techniques in functional genetics like fluorescence in situ hybridisation or fluorescently labelled expression markers demand high resolution fluorescence microscopy. Nevertheless tardigrades are still considered to be difficult objects for fluorescence techniques as they are covered by an opaque and diffracting cuticle. We show a modern technique of structured light illumination that enables us to acquire thin optical sections and consequently to reconstruct 3-dimensional structures in tardigrades with a high spatial resolution in all 3 dimensions. This technique is evaluated on taxonomically valuable internal as well as external structures of eutardigrades: the bucco-pharyngeal apparatus and the claws. The 3-dimensional reconstructions allow the measurement of distances in all 3 dimensions.

  5. An inflammation-targeting hydrogel for local drug delivery in inflammatory bowel disease

    Zhang, Sufeng; Ermann, Joerg; Succi, Marc D.; Zhou, Allen; Hamilton, Matthew J.; Cao, Bonnie; Korzenik, Joshua R.; Glickman, Jonathan N.; Vemula, Praveen K.; Glimcher, Laurie H.; Traverso, Giovanni; Langer, Robert; Karp, Jeffrey M.

    2015-01-01

    There is a clinical need for new, more effective treatments for chronic and debilitating inflammatory bowel disease (IBD), including Crohn’s disease and ulcerative colitis. Targeting drugs selectively to the inflamed intestine may improve therapeutic outcomes and minimize systemic toxicity. We report the development of an inflammation-targeting hydrogel (IT-hydrogel) that acts as a drug delivery system to the inflamed colon. Hydrogel microfibers were generated from ascorbyl palmitate, an amph...

  6. Decay vertex reconstruction and 3-dimensional lifetime determination at BESⅢ

    XU Min; HE Kang-Lin; ZHANG Zi-Ping; WANG Yi-Fang; BIAN Jian-Ming; CAO Guo-Fu; CAO Xue-Xiang; CHEN Shen-Jian; DENG Zi-Yan; FU Cheng-Dong; GAO Yuan-Ning; HAN Lei; NAN Shao-Qing; HE Miao; HU Ji-Feng; HU Xiao-Wei; HUANG Bin; HUANG Xing-Tao; JIA Lu-Kui; JI Xiao-Sin; LI Hai-Bo; LI Wei-Dong; LIANG Yu-Wie; LIU Chun-Xiu; LIU Huai-Min; LIU Ying; LIU Yong; LUO Tao; L(U) Qi-Wen; MA Qiu-Mei; MA Xiang; MAO Ya-Jun; MAO Ze-Pu; MO Xiao-Hu; NING Fei-Peng; PING Rong-Gang; QIU Jin-Fa; SONG Wen-Bo; SUN Sheng-Sen; SUN Xiao-Dong; SUN Yong-Zhao; TIAN Hao-Lai; WANG Ji-Ke; WANG Liang-Liang; WEN Shuo-Pin; WU Ling-Hui; WU Zhi; XIE Yu-Guang; YAN Jie; YAN Liang; YAO Jian; YUAN Chang-Zheng; YUAN Ye; ZHANG Chang-Chun; ZHANG Jian-Yong; ZHANG Lei; ZHANG Xue-Yao; ZHANG Yao; ZHENG Yang-Heng; ZHU Yong-Sheng; ZOU Jia-Heng

    2009-01-01

    This paper focuses mainly on the vertex reconstruction of resonance particles with a relatively long lifetime such as KSO, A, as well as on lifetime measurements using a 3-dimensional fit. The kinematic constraints between the production and decay vertices and the decay vertex fitting algorithm based on the least squares method are both presented. Reconstruction efficiencies including experimental resolutions are discussed. The results and systematic errors are calculated based on a Monte Carlo simulation.

  7. Catalytic carbon deposition on 3-dimensional carbon fibre supports

    Thornton, Matthew James

    2005-01-01

    Catalytic carbon deposition reactions, using methane, ethane or synthetic natural gas (1.8 vol. % propane, 6.7 vol. % ethane and balance methane) as the carbon-containing gas feedstock with or without the addition of hydrogen, have been investigated over nickel, cobalt and iron catalysts supported on 3-dimensional carbon fibre supports, using both a horizontal tube furnace and an isothermal, isobaric induction furnace. The transition metal catalysts were prepared by impregnating 3-dimens...

  8. Anti-de Sitter 3-dimensional Gravity with Torsion

    Blagojevic, M; Vasilic, M.

    2004-01-01

    Using the canonical formalism, we study the asymptotic symmetries of the topological 3-dimensional gravity with torsion. In the anti-de Sitter sector, the symmetries are realized by two independent Virasoro algebras with classical central charges. In the simple case of the teleparallel vacuum geometry, the central charges are equal to each other and have the same value as in general relativity, while in the general Riemann-Cartan geometry, they become different.

  9. Temporal, 3-dimensional, cellular anatomy of corneal wound tissue.

    Jester, J V; Petroll, W M; Barry, P. A.; Cavanagh, H D

    1995-01-01

    We have evaluated temporally the 3-dimensional cellular anatomy of corneal wound tissue in the rabbit eye using in vivo tandem scanning confocal microscopy. In vivo microscopic studies showed that corneal fibroblast migrated into the wound as an interconnected cellular meshwork with long, thin, randomly oriented cell processes. Interconnection of fibroblasts was further confirmed by localisation of monoclonal antibodies to connexin 43 which demonstrated prominent staining of putative gap junc...

  10. Invasive 3-Dimensional Organotypic Neoplasia from Multiple Normal Human Epithelia

    Ridky, Todd W.; Chow, Jennifer M.; Wong, David J.; Khavari, Paul A

    2010-01-01

    Refined cancer models are required to assess the burgeoning number of potential targets for cancer therapeutics within a rapid and clinically relevant context. Here we utilize tumor-associated genetic pathways to transform primary human epithelial cells from epidermis, oropharynx, esophagus, and cervix into genetically defined tumors within a human 3-dimensional (3-D) tissue environment incorporating cell-populated stroma and intact basement membrane. These engineered organotypic tissues reca...

  11. GLOBAL STABILITY IN TIME-DELAYED 3-DIMENSIONAL RICHARDS MODEL

    2010-01-01

    We obtain the global attractivity and global asymptotical stability of positive equilibria to a 3-dimensional Richards model with delays. Our results do not depend on the size-asymmetry parameter which measures the degree of the curvature of size-growth among individuals over the entire growth curve, and the shape parameter which affects the shape of model curve. Lastly, we gave a numerical simulation to verify the feasibility of our main results.

  12. Circuit-Switched Gossiping in the 3-Dimensional Torus Networks

    Delmas, Olivier; Pérennes, Stéphane

    1996-01-01

    In this paper we describe, in the case of short messages, an efficient gossiping algorithm for 3-dimensional torus networks (wrap-around or toroidal meshes) that uses synchronous circuit-switched routing. The algorithm is based on a recursive decomposition of a torus. The algorithm requires an optimal number of rounds and a quasi-optimal number of intermediate switch settings to gossip in an $7^i \\times 7^i \\times 7^i$ torus.

  13. The 3-Dimensional Core Model DYN3D

    Mittag, Siegfried; Rohde, Ulrich; Grundmann, Ulrich

    2010-01-01

    Analyzing the safety margins in transients and accidents of nuclear reactors 3-dimensional models of the core were used to avoid conservative assumptions needed for point kinetics or 1-dimensional models. Therefore the 3D code DYN3D has been developed for the analysis of reactivity initiated accidents (RIA) in thermal nuclear reactors. The power distributions are calculated with the help of nodal expansion methods (NEM) for hexagonal and Cartesian geometry. The fuel rod model and the thermohy...

  14. LWR core safety analysis with Areva's 3-dimensional methods

    The quality of the safety analysis strongly affects the confidence in the operational safety of a reactor. To ensure the highest quality, it is essential that the methodology consists of appropriate analysis tools and an extensive validation base. Sophisticated 3-dimensional core models ensure that all physical effects relevant for safety are treated and the results are reliable and conservative. The validation base includes measurement campaigns in test facilities and comparisons of the predictions of steady state and transient measured data gathered from plants during many years of operation. Thus, the core models achieve reliable and comprehensive results for a wide range of applications. As an example an overview of the application experience as well as the validation base of AREVA's 3-dimensional codes is given. The importance and necessity of the comprehensive 3-dimensional methodology is illustrated with examples of a BWR and PWR safety analysis. For BWR transient application the analysis of regional power oscillations is considered and regarding the PWR safety analysis an example referring to fast enthalpy rise and the maximum fuel temperature caused by a rod ejection accident is shown. (orig.)

  15. Controlled release of simvastatin from in situ forming hydrogel triggers bone formation in MC3T3-E1 cells.

    Park, Yoon Shin; David, Allan E; Park, Kyung Min; Lin, Chia-Ying; Than, Khoi D; Lee, Kyuri; Park, Jun Beom; Jo, Inho; Park, Ki Dong; Yang, Victor C

    2013-04-01

    Simvastatin (SIM), a drug commonly administered for the treatment of hypercholesterolemia, has been recently reported to induce bone regeneration/formation. In this study, we investigated the properties of hydrogel composed of gelatin-poly(ethylene glycol)-tyramine (GPT) as an efficient SIM delivery vehicle that can trigger osteogenic differentiation. Sustained delivery of SIM was achieved through its encapsulation in an injectable, biodegradable GPT-hydrogel. Cross-linking of the gelatin-based GPT-hydrogel was induced by the reaction of horse radish peroxidase and H(2)O(2). GPT-hydrogels of three different matrix stiffness, 1,800 (GPT-hydrogel1), 5,800 (GPT-hydrogel2), and 8,400 Pa (GPT-hydrogel3) were used. The gelation/degradation time and SIM release profiles of hydrogels loaded with two different concentrations of SIM, 1 and 3 mg/ml, were also evaluated. Maximum swelling times of GPT-hydrogel1, GPT-hydrogel2, and GPT-hydrogel3 were observed to be 6, 12, and 20 days, respectively. All GPT-hydrogels showed complete degradation within 55 days. The in vitro SIM release profiles, investigated in PBS buffer (pH 7.4) at 37°C, exhibited typical biphasic release patterns with the initial burst being more rapid with GPT-hydrogel1 compared with GPT-hydrogel3. Substantial increase in matrix metalloproteinase-13, osteocalcin expression levels, and mineralization were seen in osteogenic differentiation system using MC3T3-E1 cells cultured with GPT-hydrogels loaded with SIM in a dose-dependent manner. This study demonstrated that controlled release of SIM from a biodegradable, injectable GPT-hydrogel had a promising role for long-term treatment of chronic degenerative diseases such as disc degenerative disease. PMID:23250670

  16. Thermo-responsive hydrogels for intravitreal injection and biomolecule release

    Drapala, Pawel

    In this dissertation, we develop an injectable polymer system to enable localized and prolonged release of therapeutic biomolecules for improved treatment of Age-Related Macular Degeneration (AMD). Thermo-responsive hydrogels derived from N-isopropylacrylamide (NIPAAm) and cross-linked with poly(ethylene glycol) (PEG) poly(L-Lactic acid) (PLLA) copolymer were synthesized via free-radical polymerization. These materials were investigated for (a) phase change behavior, (b) in-vitro degradation, (c) capacity for controlled drug delivery, and (d) biocompatibility. The volume-phase transition temperature (VPTT) of the PNIPAAm- co-PEG-b-PLLA hydrogels was adjusted using hydrophilic and hydrophobic moieties so that it is ca. 33°C. These hydrogels did not initially show evidence of degradation at 37°C due to physical cross-links of collapsed PNIPAAm. Only after addition of glutathione chain transfer agents (CTA)s to the precursor did the collapsed hydrogels become fully soluble at 37°C. CTAs significantly affected the release kinetics of biomolecules; addition of 1.0 mg/mL glutathione to 3 mM cross-linker accelerated hydrogel degradation, resulting in 100% release in less than 2 days. This work also explored the effect of PEGylation in order to tether biomolecules to the polymer matrix. It was demonstrated that non-site-specific PEGylation can postpone the burst release of solutes (up to 10 days in hydrogels with 0.5 mg/mL glutathione). Cell viability assays showed that at least two 20-minute buffer extraction steps were needed to remove cytotoxic elements from the hydrogels. Clinically-used therapeutic biomolecules LucentisRTM and AvastinRTM were demonstrated to be both stable and bioactive after release form PNIPAAm-co-PEG-b-PLLA hydrogels. The thermo-responsive hydrogels presented here offer a promising platform for the localized delivery of proteins such as recombinant antibodies.

  17. Injectable osteogenic and angiogenic nanocomposite hydrogels for irregular bone defects.

    Vishnu Priya, M; Sivshanmugam, A; Boccaccini, A R; Goudouri, O M; Sun, Wook; Hwang, Nathaniel; Deepthi, S; Nair, Shantikumar V; Jayakumar, R

    2016-01-01

    Injectable hydrogels with their 3D structure and good moldability serve as excellent scaffolding material for regenerating irregular non load-bearing bone defects. Most of the bone defects do not heal completely due to the lack of vasculature required for the transport of nutrients and oxygen to the regenerating tissues. To enhance vasculature, we developed an injectable hydrogel system made of chitin and poly (butylene succinate) (PBSu) loaded with 250  ±  20 nm sized fibrin nanoparticles (FNPs) and magnesium-doped bioglass (MBG). FNPs were expected to enhance vascularisation and MBG was expected to help induce early osteogenesis. Composite hydrogels were analysed using Fourier transform infra-red spectroscopy, scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy, and rheology. Hydrogels with MBG showed a slightly rougher morphology upon SEM analysis. Composites containing 5% MBG and 2% FNPs showed good rheological properties, injectability, temperature stability, biomineralization and protein adsorption. Human umbilical vein endothelial cells (HUVECs) and rabbit-adipose derived mesenchymal stem cells (rASCs) were used for cyto-compatibility studies. Composite gels with 2% FNPs and 2% MBG (composite 1) were considered to be non-toxic to both the cells and were taken for further in vitro studies. Aortic ring assay was carried out to study the angiogenic potential of the hydrogels. The aorta placed with composite hydrogels showed enhanced sprouting of blood vessels. rASCs too showed good spreading on the composite hydrogels. Hydrogels containing MBG showed early initiation of differentiation and higher expression of alkaline phosphatase and osteocalcin confirming the osteoinductive property of MBG. These studies indicate that this composite hydrogel can be used for regenerating irregular bone defects. PMID:27305426

  18. Designing Cell-Compatible Hydrogels for Biomedical Applications

    Seliktar, Dror

    2012-06-01

    Hydrogels are polymeric materials distinguished by high water content and diverse physical properties. They can be engineered to resemble the extracellular environment of the body’s tissues in ways that enable their use in medical implants, biosensors, and drug-delivery devices. Cell-compatible hydrogels are designed by using a strategy of coordinated control over physical properties and bioactivity to influence specific interactions with cellular systems, including spatial and temporal patterns of biochemical and biomechanical cues known to modulate cell behavior. Important new discoveries in stem cell research, cancer biology, and cellular morphogenesis have been realized with model hydrogel systems premised on these designs. Basic and clinical applications for hydrogels in cell therapy, tissue engineering, and biomedical research continue to drive design improvements using performance-based materials engineering paradigms.

  19. Biomimetic macroporous hydrogels

    Sedlačík, Tomáš; Proks, Vladimír; Šlouf, Miroslav; Studenovská, Hana; Dušková, Miroslava; Rypáček, František

    Prague : Institute of Macromolecular Chemistry AS CR, 2015. s. 69. ISBN 978-80-85009-82-8. [Functional Polymers at Bio -Material Interfaces - 79th Prague Meeting on Macromolecules. 28.06.2015-02.07.2015, Prague] Institutional support: RVO:61389013 Keywords : click chemistry * hydrogels Subject RIV: CD - Macromolecular Chemistry

  20. 25th Anniversary Article: Rational Design and Applications of Hydrogels in Regenerative Medicine

    Annabi, Nasim; Tamayol, Ali; Uquillas, Jorge Alfredo; Akbari, Mohsen; Bertassoni, Luiz E.; Cha, Chaenyung; Camci-Unal, Gulden; Dokmeci, Mehmet R.; Peppas, Nicholas A.; Khademhosseini, Ali

    2013-01-01

    Hydrogels are hydrophilic polymer-based materials with high water content and physical characteristics that resemble the native extracellular matrix. Because of their remarkable properties, hydrogel systems are used for a wide range of biomedical applications, such as three-dimensional (3D) matrices for tissue engineering, drug-delivery vehicles, composite biomaterials, and as injectable fillers in minimally invasive surgeries. In addition, the rational design of hydrogels with controlled phy...

  1. Astrocytes alignment and reactivity on collagen hydrogels patterned with ECM proteins

    Hsiao, Tony W.; Tresco, Patrick A.; Hlady, Vladimir

    2014-01-01

    To modulate the surface properties of collagen and subsequent cell-surface interactions, a method was developed to transfer protein patterns from glass coverslips to collagen type I hydrogel surfaces. Two proteins and one proteoglycan found in central nervous system extracellular matrix as well as fibrinogen were patterned in stripes onto collagen hydrogel and astrocytes were cultured on these surfaces. The addition of the stripe protein patterns to hydrogels created astrocyte layers in which...

  2. Biomedical applications of hydrogels: a review of patents and commercial products

    Caló, Enrica; Khutoryanskiy, Vitaliy V.

    2015-01-01

    Hydrogels have become very popular due to their unique properties such as high water content, softness, flexibility and biocompatibility. Natural and synthetic hydrophilic polymers can be physically or chemically cross-linked in order to produce hydrogels. Their resemblance to living tissue opens up many opportunities for applications in biomedical areas. Currently, hydrogels are used for manufacturing contact lenses, hygiene products, tissue engineering scaffolds, drug delivery systems and w...

  3. Multi-functions of hydrogel with bilayer-based lamellar structure

    Haque, Md. Anamul; Gong, Jian Ping

    2013-01-01

    A novel hybrid hydrogel has been developed by combining bilayer-based lamellar structure of a self-assembled polymer surfactant and polymer network of conventional hydrogel system. A wide range of lamellar structure from micro-domain up to macro-domain (cm-scale) has been successfully generated in the hydrogel. Flat, infinitely large, and perfectly aligned lamellar macro-domain was formed by applying mechanical shear to the gel forming precursor solution containing monomer, cross-linker, and ...

  4. Formulation and Evaluation of Topical Hydrogel Patch Containing Amide Type Local Anaesthetic Agent

    Jayrajsinh Sarvaiya; Chintan Tank; Kosanam Divakar; Jay Upadhyay; G.K.Kapse

    2012-01-01

    Hydrogel based drug delivery systems provides significant effect in designing sustained release topical dosage forms. Topical patch containing drug in hydrogel type polymer matrix provides not only targeted drug flux through the skin but also provides cooling effect on application site. Topical hydrogel patch containing lidocaine was prepared by using sodium poly acrylate as bioadhesive polymer. Effect of brij 30 and transcutol was also evaluated on topical flux of lidocaine base from hydroge...

  5. Local delivery of rhenium-188 colloid into hepatic tumor sites in rats using thermo-sensitive chitosan hydrogel: effects of gelling time of chitosan as delivery system

    A previously developed internal radiation therapy mode adopting a thermo-sensitive, chitosan-based hydrogel intended for local delivery of 188Re-Tin colloid drug was extended to test for its applicability to the treatment of hepatoma in rats. The effects of two formulations of hydrogel with different gel times and two methods of delivering the hydrogel containing 188Re-Tin colloid into tumors on the accumulated dose and duration of radioactivity within tumor were first studied by in vitro release, planar scintigraphy, and bio-distribution evaluations. Results from this initial study suggest that a treatment mode using the intratumoral delivery method and a 4 min gel time hydrogel to deliver the 188Re-Tin colloid into the tumor is more effective for treating hepatoma in rats. The treatment mode was then further verified through efficacy evaluations based on hepatic tumor growth in hepatoma-bearing rats. In conclusion, the application of chitosan/β-glycero-phosphate (C/GP) hydrogel for the local delivery of 188Re-Tin colloid to treat hepatoma in rats is feasible. The effective and efficient treatment mode consists of the intratumoral injection of 188Re-Tin colloid premixed with 4 min gel time C/GP hydrogel. (author)

  6. Sustained-release hydrogels of topotecan for retinoblastoma.

    Taich, Paula; Moretton, Marcela A; Del Sole, María Jose; Winter, Ursula; Bernabeu, Ezequiel; Croxatto, Juan O; Oppezzo, Javier; Williams, Gustavo; Chantada, Guillermo L; Chiappetta, Diego A; Schaiquevich, Paula

    2016-10-01

    Treatment of retinoblastoma, the most common primary ocular malignancy in children, has greatly improved over the last decade. Still, new devices for chemotherapy are needed to achieve better tumor control. The aim of this project was to develop an ocular drug delivery system for topotecan (TPT) loaded in biocompatible hydrogels of poly(ε-caprolactone)-poly(ethyleneglycol)-poly(ε-caprolactone) block copolymers (PCL-PEG-PCL) for sustained TPT release in the vitreous humor. Hydrogels were prepared from TPT and synthesized PCL-PEG-PCL copolymers. Rheological properties and in vitro and in vivo TPT release were studied. Hydrogel cytotoxicity was evaluated in retinoblastoma cells as a surrogate for efficacy and TPT vitreous pharmacokinetics and systemic as well as ocular toxicity were evaluated in rabbits. The pseudoplastic behavior of the hydrogels makes them suitable for intraocular administration. In vitro release profiles showed a sustained release of TPT from PCL-PEG-PCL up to 7days and drug loading did not affect the release pattern. Blank hydrogels did not affect retinoblastoma cell viability but 0.4% (w/w) TPT-loaded hydrogel was highly cytotoxic for at least 7days. After intravitreal injection, TPT vitreous concentrations were sustained above the pharmacologically active concentration. One month after injection, animals with blank or TPT-loaded hydrogels showed no systemic toxicity or retinal impairment on fundus examination, electroretinographic, and histopathological assessments. These novel TPT-hydrogels can deliver sustained concentrations of active drug into the vitreous with excellent biocompatibility in vivo and pronounced cytotoxic activity in retinoblastoma cells and may become an additional strategy for intraocular retinoblastoma treatment. PMID:27429296

  7. A practical guide to hydrogels for cell culture.

    Caliari, Steven R; Burdick, Jason A

    2016-04-28

    There is growing appreciation of the role that the extracellular environment plays in regulating cell behavior. Mechanical, structural, and compositional cues, either alone or in concert, can drastically alter cell function. Biomaterials, and particularly hydrogels, have been developed and implemented to present defined subsets of these cues for investigating countless cellular processes as a means of understanding morphogenesis, aging, and disease. Although most scientists concede that standard cell culture materials (tissue culture plastic and glass) do a poor job of recapitulating native cellular milieus, there is currently a knowledge barrier for many researchers in regard to the application of hydrogels for cell culture. Here, we introduce hydrogels to those who may be unfamiliar with procedures to culture and study cells with these systems, with a particular focus on commercially available hydrogels. PMID:27123816

  8. BIOCOMPATIBILITY EVALUATION OF XANTHAN/CHONDROITIN SULFATE HYDROGELS

    Ana-Maria Oprea

    2012-03-01

    Full Text Available The in vitro and in vivo biocompatibility of xanthan/chondroitin sulfate hydrogels (X/CS in differentmixing ratios was investigated. The in vitro biocompatibility evaluation was performed by a chemiluminescent assayusing microorganisms such as Saccharomyces pombe. The cellular growth of S. pombe in presence of thexanthan/chondroitin sulfate hydrogels containing up to 20 % chondroitin sulfate was examinated comparatively withxanthan hydrogel.The in vivo evaluation was performed by toxicity test and subcutaneously implantation in rats. It has been establisheda lethal dose (LD50 bigger than 3200 mg/kg for all studied hydrogels, therefore they are nontoxic materials.The in vivo 30 days testing performed by subcutaneous implantation showed that the X/CS matrices were easilyabsorbed without side-effects, demonstrating their biocompatibility and effectiveness as potential drug delivery systems.

  9. Hamiltonian Analysis of 3-Dimensional Connection Dynamics in Bondi-like Coordinates

    Huang, Chao-Guang

    2016-01-01

    The Hamiltonian analysis for a 3-dimensional $SO(1,1)\\times T_+$-connection dynamics is conducted in a Bondi-like coordinate system.A null coframe with 5 independent variables and 9 connection coefficients are treated as basic configuration variables.All constraints and their consistency conditions, as well as the equations of motion,for the system are presented.There is no physical degree of freedom in the system as expected.The Ba\\~nados-Teitelboim-Zanelli spacetime as an example is used to check the analysis.

  10. Formulation and Evaluation of Topical Hydrogel Patch Containing Amide Type Local Anaesthetic Agent

    Jayrajsinh Sarvaiya

    2012-09-01

    Full Text Available Hydrogel based drug delivery systems provides significant effect in designing sustained release topical dosage forms. Topical patch containing drug in hydrogel type polymer matrix provides not only targeted drug flux through the skin but also provides cooling effect on application site. Topical hydrogel patch containing lidocaine was prepared by using sodium poly acrylate as bioadhesive polymer. Effect of brij 30 and transcutol was also evaluated on topical flux of lidocaine base from hydrogel patch. Transcutol (10% w/w provides sufficient drug release in contrast to brij 30(4%w/w in prepared hydrogel patches. Maintenance of uniformity of weight is one of the critical task in preparation of hydrogel patch as polymers used are highly water absorbent. Excess amount of penetration enhancers leads to alter adhesive property of bioadhesive patch so formulation was optimized with Sodium polyacrylate (7%w/w as the desired concentration for necessary bioadhesiveness and zinc oxide as cross linking agent.

  11. Mussel-mimetic protein-based adhesive hydrogel.

    Kim, Bum Jin; Oh, Dongyeop X; Kim, Sangsik; Seo, Jeong Hyun; Hwang, Dong Soo; Masic, Admir; Han, Dong Keun; Cha, Hyung Joon

    2014-05-12

    Hydrogel systems based on cross-linked polymeric materials which could provide both adhesion and cohesion in wet environment have been considered as a promising formulation of tissue adhesives. Inspired by marine mussel adhesion, many researchers have tried to exploit the 3,4-dihydroxyphenylalanine (DOPA) molecule as a cross-linking mediator of synthetic polymer-based hydrogels which is known to be able to achieve cohesive hardening as well as adhesive bonding with diverse surfaces. Beside DOPA residue, composition of other amino acid residues and structure of mussel adhesive proteins (MAPs) have also been considered important elements for mussel adhesion. Herein, we represent a novel protein-based hydrogel system using DOPA-containing recombinant MAP. Gelation can be achieved using both oxdiation-induced DOPA quinone-mediated covalent and Fe(3+)-mediated coordinative noncovalent cross-linking. Fe(3+)-mediated hydrogels show deformable and self-healing viscoelastic behavior in rheological analysis, which is also well-reflected in bulk adhesion strength measurement. Quinone-mediated hydrogel has higher cohesive strength and can provide sufficient gelation time for easier handling. Collectively, our newly developed MAP hydrogel can potentially be used as tissue adhesive and sealant for future applications. PMID:24650082

  12. Direct 3D Printing of Shear-Thinning Hydrogels into Self-Healing Hydrogels.

    Highley, Christopher B; Rodell, Christopher B; Burdick, Jason A

    2015-09-01

    Supramolecular hydrogels are used in the 3D printing of high-resolution, multi-material structures. The non-covalent bonds allow the extrusion of the inks into support gels to directly write structures continuously in 3D space. This material system supports the patterning of multiple inks, cells, and void spaces. PMID:26177925

  13. Injectable in situ forming xylitol-PEG-based hydrogels for cell encapsulation and delivery.

    Selvam, Shivaram; Pithapuram, Madhav V; Victor, Sunita P; Muthu, Jayabalan

    2015-02-01

    Injectable in situ crosslinking hydrogels offer unique advantages over conventional prefabricated hydrogel methodologies. Herein, we synthesize poly(xylitol-co-maleate-co-PEG) (pXMP) macromers and evaluate their performance as injectable cell carriers for tissue engineering applications. The designed pXMP elastomers were non-toxic and water-soluble with viscosity values permissible for subcutaneous injectable systems. pXMP-based hydrogels prepared via free radical polymerization with acrylic acid as crosslinker possessed high crosslink density and exhibited a broad range of compressive moduli that could match the natural mechanical environment of various native tissues. The hydrogels displayed controlled degradability and exhibited gradual increase in matrix porosity upon degradation. The hydrophobic hydrogel surfaces preferentially adsorbed albumin and promoted cell adhesion and growth in vitro. Actin staining on cells cultured on thin hydrogel films revealed subconfluent cell monolayers composed of strong, adherent cells. Furthermore, fabricated 3D pXMP cell-hydrogel constructs promoted cell survival and proliferation in vitro. Cumulatively, our results demonstrate that injectable xylitol-PEG-based hydrogels possess excellent physical characteristics and exhibit exceptional cytocompatibility in vitro. Consequently, they show great promise as injectable hydrogel systems for in situ tissue repair and regeneration. PMID:25543981

  14. Research on the printability of hydrogels in 3D bioprinting

    He, Yong; Yang, FeiFei; Zhao, HaiMing; Gao, Qing; Xia, Bing; Fu, JianZhong

    2016-01-01

    As the biocompatible materials, hydrogels have been widely used in three- dimensional (3D) bioprinting/organ printing to load cell for tissue engineering. It is important to precisely control hydrogels deposition during printing the mimic organ structures. However, the printability of hydrogels about printing parameters is seldom addressed. In this paper, we systemically investigated the printability of hydrogels from printing lines (one dimensional, 1D structures) to printing lattices/films (two dimensional, 2D structures) and printing 3D structures with a special attention to the accurate printing. After a series of experiments, we discovered the relationships between the important factors such as air pressure, feedrate, or even printing distance and the printing quality of the expected structures. Dumbbell shape was observed in the lattice structures printing due to the hydrogel diffuses at the intersection. Collapses and fusion of adjacent layer would result in the error accumulation at Z direction which was an important fact that could cause printing failure. Finally, we successfully demonstrated a 3D printing hydrogel scaffold through harmonize with all the parameters. The cell viability after printing was compared with the casting and the results showed that our bioprinting method almost had no extra damage to the cells. PMID:27436509

  15. Research on the printability of hydrogels in 3D bioprinting

    He, Yong; Yang, Feifei; Zhao, Haiming; Gao, Qing; Xia, Bing; Fu, Jianzhong

    2016-07-01

    As the biocompatible materials, hydrogels have been widely used in three- dimensional (3D) bioprinting/organ printing to load cell for tissue engineering. It is important to precisely control hydrogels deposition during printing the mimic organ structures. However, the printability of hydrogels about printing parameters is seldom addressed. In this paper, we systemically investigated the printability of hydrogels from printing lines (one dimensional, 1D structures) to printing lattices/films (two dimensional, 2D structures) and printing 3D structures with a special attention to the accurate printing. After a series of experiments, we discovered the relationships between the important factors such as air pressure, feedrate, or even printing distance and the printing quality of the expected structures. Dumbbell shape was observed in the lattice structures printing due to the hydrogel diffuses at the intersection. Collapses and fusion of adjacent layer would result in the error accumulation at Z direction which was an important fact that could cause printing failure. Finally, we successfully demonstrated a 3D printing hydrogel scaffold through harmonize with all the parameters. The cell viability after printing was compared with the casting and the results showed that our bioprinting method almost had no extra damage to the cells.

  16. Research on the printability of hydrogels in 3D bioprinting.

    He, Yong; Yang, FeiFei; Zhao, HaiMing; Gao, Qing; Xia, Bing; Fu, JianZhong

    2016-01-01

    As the biocompatible materials, hydrogels have been widely used in three- dimensional (3D) bioprinting/organ printing to load cell for tissue engineering. It is important to precisely control hydrogels deposition during printing the mimic organ structures. However, the printability of hydrogels about printing parameters is seldom addressed. In this paper, we systemically investigated the printability of hydrogels from printing lines (one dimensional, 1D structures) to printing lattices/films (two dimensional, 2D structures) and printing 3D structures with a special attention to the accurate printing. After a series of experiments, we discovered the relationships between the important factors such as air pressure, feedrate, or even printing distance and the printing quality of the expected structures. Dumbbell shape was observed in the lattice structures printing due to the hydrogel diffuses at the intersection. Collapses and fusion of adjacent layer would result in the error accumulation at Z direction which was an important fact that could cause printing failure. Finally, we successfully demonstrated a 3D printing hydrogel scaffold through harmonize with all the parameters. The cell viability after printing was compared with the casting and the results showed that our bioprinting method almost had no extra damage to the cells. PMID:27436509

  17. Interfacial thiol-ene photoclick reactions for forming multilayer hydrogels.

    Shih, Han; Fraser, Andrew K; Lin, Chien-Chi

    2013-03-13

    Interfacial visible light-mediated thiol-ene photoclick reactions were developed for preparing step-growth hydrogels with multilayer structures. The effect of a noncleavage type photoinitiator eosin-Y on visible-light-mediated thiol-ene photopolymerization was first characterized using in situ photorheometry, gel fraction, and equilibrium swelling ratio. Next, spectrophotometric properties of eosin-Y in the presence of various relevant macromer species were evaluated using ultraviolet-visible light (UV-vis) spectrometry. It was determined that eosin-Y was able to reinitiate the thiol-ene photoclick reaction, even after light exposure. Because of its small molecular weight, most eosin-Y molecules readily leached out from the hydrogels. The diffusion of residual eosin-Y from preformed hydrogels was exploited for fabricating multilayer step-growth hydrogels. Interfacial hydrogel coating was formed via the same visible-light-mediated gelation mechanism without adding fresh initiator. The thickness of the thiol-ene gel coating could be easily controlled by adjusting visible light exposure time, eosin-Y concentration initially loaded in the core gel, or macromer concentration in the coating solution. The major benefits of this interfacial thiol-ene coating system include its simplicity and cytocompatibility. The formation of thiol-ene hydrogels and coatings neither requires nor generates any cytotoxic components. This new gelation chemistry may have great utilities in controlled release of multiple sensitive growth factors and encapsulation of multiple cell types for tissue regeneration. PMID:23384151

  18. Thermal-Responsive Behavior of a Cell Compatible Chitosan/Pectin Hydrogel.

    Birch, Nathan P; Barney, Lauren E; Pandres, Elena; Peyton, Shelly R; Schiffman, Jessica D

    2015-06-01

    Biopolymer hydrogels are important materials for wound healing and cell culture applications. While current synthetic polymer hydrogels have excellent biocompatibility and are nontoxic, they typically function as a passive matrix that does not supply any additional bioactivity. Chitosan (CS) and pectin (Pec) are natural polymers with active properties that are desirable for wound healing. Unfortunately, the synthesis of CS/Pec materials have previously been limited by harsh acidic synthesis conditions, which further restricted their use in biomedical applications. In this study, a zero-acid hydrogel has been synthesized from a mixture of chitosan and pectin at biologically compatible conditions. For the first time, we demonstrated that salt could be used to suppress long-range electrostatic interactions to generate a thermoreversible biopolymer hydrogel that has temperature-sensitive gelation. Both the hydrogel and the solution phases are highly elastic, with a power law index of close to -1. When dried hydrogels were placed into phosphate buffered saline solution, they rapidly rehydrated and swelled to incorporate 2.7× their weight. As a proof of concept, we removed the salt from our CS/Pec hydrogels, thus, creating thick and easy to cast polyelectrolyte complex hydrogels, which proved to be compatible with human marrow-derived stem cells. We suggest that our development of an acid-free CS/Pec hydrogel system that has excellent exudate uptake, holds potential for wound healing bandages. PMID:25932898

  19. Chemically cross-linked silk fibroin hydrogel with enhanced elastic properties, biodegradability, and biocompatibility

    Kim MH

    2016-06-01

    Full Text Available Min Hee Kim, Won Ho Park Department of Advanced Organic Materials and Textile Engineering System, Chungnam National University, Daejeon, Korea Abstract: In this study, the synthesis of silk fibroin (SF hydrogel via chemical cross-linking reactions of SF due to gamma-ray (γ-ray irradiation was investigated, as were the resultant hydrogel’s properties. Two different hydrogels were investigated: physically cross-linked SF hydrogel and chemically cross-linked SF hydrogel irradiated at different doses of γ-rays. The effects of the irradiation dose and SF concentration on the hydrogelation of SF were examined. The chemically cross-linked SF hydrogel was compared with the physically cross-linked one with regard to secondary structure and gel strength. Furthermore, the swelling behavior, crystallinity, and biodegradation of the SF hydrogels were characterized. To assay cell proliferation, the cell viability of human mesenchymal stem cells on the lyophilized SF hydrogel scaffolds was evaluated, and no significant cytotoxicity against human mesenchymal stem cells was observed. Keywords: silk fibroin, hydrogels, biodegradation rate, gamma irradiation, cross-linking

  20. Double network bacterial cellulose hydrogel to build a biology-device interface

    Shi, Zhijun; Li, Ying; Chen, Xiuli; Han, Hongwei; Yang, Guang

    2013-12-01

    Establishing a biology-device interface might enable the interaction between microelectronics and biotechnology. In this study, electroactive hydrogels have been produced using bacterial cellulose (BC) and conducting polymer (CP) deposited on the BC hydrogel surface to cover the BC fibers. The structures of these composites thus have double networks, one of which is a layer of electroactive hydrogels combined with BC and CP. The electroconductivity provides the composites with capabilities for voltage and current response, and the BC hydrogel layer provides good biocompatibility, biodegradability, bioadhesion and mass transport properties. Such a system might allow selective biological functions such as molecular recognition and specific catalysis and also for probing the detailed genetic and molecular mechanisms of life. A BC-CP composite hydrogel could then lead to a biology-device interface. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) are used here to study the composite hydrogels' electroactive property. BC-PAni and BC-PPy respond to voltage changes. This provides a mechanism to amplify electrochemical signals for analysis or detection. BC hydrogels were found to be able to support the growth, spreading and migration of human normal skin fibroblasts without causing any cytotoxic effect on the cells in the cell culture. These double network BC-CP hydrogels are biphasic Janus hydrogels which integrate electroactivity with biocompatibility, and might provide a biology-device interface to produce implantable devices for personalized and regenerative medicine.

  1. Scientific visualization of 3-dimensional optimized stellarator configurations

    The design techniques and physics analysis of modern stellarator configurations for magnetic fusion research rely heavily on high performance computing and simulation. Stellarators, which are fundamentally 3-dimensional in nature, offer significantly more design flexibility than more symmetric devices such as the tokamak. By varying the outer boundary shape of the plasma, a variety of physics features, such as transport, stability, and heating efficiency can be optimized. Scientific visualization techniques are an important adjunct to this effort as they provide a necessary ergonomic link between the numerical results and the intuition of the human researcher. The authors have developed a variety of visualization techniques for stellarators which both facilitate the design optimization process and allow the physics simulations to be more readily understood

  2. Incorporating interactive 3-dimensional graphics in astronomy research papers

    Barnes, David G

    2007-01-01

    Most research data collections created or used by astronomers are intrinsically multi-dimensional. In contrast, all visual representations of data presented within research papers are exclusively 2-dimensional. We present a resolution of this dichotomy that uses a novel technique for embedding 3-dimensional (3-d) visualisations of astronomy data sets in electronic-format research papers. Our technique uses the latest Adobe Portable Document Format extensions together with a new version of the S2PLOT programming library. The 3-d models can be easily rotated and explored by the reader and, in some cases, modified. We demonstrate example applications of this technique including: 3-d figures exhibiting subtle structure in redshift catalogues, colour-magnitude diagrams and halo merger trees; 3-d isosurface and volume renderings of cosmological simulations; and 3-d models of instructional diagrams and instrument designs.

  3. Protalign: a 3-dimensional protein alignment assessment tool.

    Meads, D; Hansen, M D; Pang, A

    1999-01-01

    Protein fold recognition (sometimes called threading) is the prediction of a protein's 3-dimensional shape based on its similarity to a protein of known structure. Fold predictions are low resolution; that is, no effort is made to rotate the protein's component amino acid side chains into their correct spatial orientations. The goal is simply to recognize the protein family member that most closely resembles the target sequence of unknown structure and to create a sensible alignment of the target to the known structure (i.e., a structure-sequence alignment). To facilitate this type of structure prediction, we have designed a low resolution molecular graphics tool. ProtAlign introduces the ability to interact with and edit alignments directly in the 3-dimensional structure as well as in the usual 2-dimensional layout. It also contains several functions and features to help the user assess areas within the alignment. ProtAlign implements an open pipe architecture to allow other programs to access its molecular graphics capabilities. In addition, it is capable of "driving" other programs. Because amino acid side chain orientation is not relevant in fold recognition, we represent amino acid residues as abstract shapes or glyphs much like Lego (tm) blocks and we borrow techniques from comparative flow visualization using streamlines to provide clean depictions of the entire protein model. By creating a low resolution representation of protein structure, we are able to at least double the amount of information on the screen. At the same time, we create a view that is not as busy as the corresponding representations using traditional high resolution visualization methods which show detailed atomic structure. This eliminates distracting and possibly misleading visual clutter resulting from the mapping of protein alignment information onto a high resolution display of the known structure. This molecular graphics program is implemented in Open GL to facilitate porting to

  4. MESO-STRUCTURED POLYMERIC HYDROGELS

    Zhen-zhong Yang; Jian-hua Rong; Dan Li

    2003-01-01

    Meso-structured (opal and inverse opal) polymeric hydrogels of varied morphology and composition were prepared by using two methods: post-modification of the template-synthesized structured polymers and templatepolymerization of functional monomers. A polyacrylic acid based inverse opal hydrogel was chosen to demonstrate its fast pH response by changing color, which is important in designing tunable photonic crystals. Template effects of the hydrogels on controlling structure of the template-synthesized inorganic materials were discussed. The catalytic effect of acid groups inthe templates was emphasized for a preferential formation of TiO2 in the region containing acid groups, which allowed duplicating inorganic colloidal crystals from colloidal crystal hydrogels (or macroporous products from macroporous hydrogels) via one step duplication.

  5. MESO—STRUCTURED POLYMERIC HYDROGELS

    Zhen-zhongYang; Jian-huaRong; DanLi

    2003-01-01

    Meso-structured(opal and inverse opal) polymeric hydrogels of varied morphology and composition were prepared by using two methods:post-modification of the template-synthesized structured polymers and templatepolymerization of functional monomers.A polyacrylic acid based inverse opal hydrogel was chosen to demonstrate its fast pH response by changing color,which is important in designing tunable photonic crystals.Template effects of the hydrogels on controlling structure of the template-synthesized inorganic materials were discussed.The catalytic effect of acid groups in the templates was emphasized for a preferential formation of TiO2 in the region containing acid groups,which allowed duplicating inorganic colloidal crystals from colloidal crystal hydrogels (or macroporous products from macroporous hydrogels) via one step duplication.

  6. An Injectable Enzymatically Crosslinked Carboxymethylated Pullulan/Chondroitin Sulfate Hydrogel for Cartilage Tissue Engineering

    Chen, Feng; Yu, Songrui; Liu, Bing; Ni, Yunzhou; Yu, Chunyang; Su, Yue; Zhu, Xinyuan; Yu, Xiaowei; Zhou, Yongfeng; Yan, Deyue

    2016-01-01

    In this study, an enzymatically cross-linked injectable and biodegradable hydrogel system comprising carboxymethyl pullulan-tyramine (CMP-TA) and chondroitin sulfate-tyramine (CS-TA) conjugates was successfully developed under physiological conditions in the presence of both horseradish peroxidase (HRP) and hydrogen peroxide (H2O2) for cartilage tissue engineering (CTTE). The HRP crosslinking method makes this injectable system feasible, minimally invasive and easily translatable for regenerative medicine applications. The physicochemical properties of the mechanically stable hydrogel system can be modulated by varying the weight ratio and concentration of polymer as well as the concentrations of crosslinking reagents. Additionally, the cellular behaviour of porcine auricular chondrocytes encapsulated into CMP-TA/CS-TA hydrogels demonstrates that the hydrogel system has a good cyto-compatibility. Specifically, compared to the CMP-TA hydrogel, these CMP-TA/CS-TA composite hydrogels have enhanced cell proliferation and increased cartilaginous ECM deposition, which significantly facilitate chondrogenesis. Furthermore, histological analysis indicates that the hydrogel system exhibits acceptable tissue compatibility by using a mouse subcutaneous implantation model. Overall, the novel injectable pullulan/chondroitin sulfate composite hydrogels presented here are expected to be useful biomaterial scaffold for regenerating cartilage tissue.

  7. Improvement in transdermal drug delivery performance by graphite oxide/temperature-responsive hydrogel composites with micro heater

    Transdermal drug delivery system (TDDS) was prepared with temperature-responsive hydrogel. The graphite was oxidized and incorporated into hydrogel matrix to improve the thermal response of hydrogel. The micro heater was fabricated to control the temperature precisely by adopting a joule heating method. The drug in hydrogel was delivered through a hairless mouse skin by controlling temperature. The efficiency of drug delivery was improved obviously by incorporation of graphite oxide due to the excellent thermal conductivity and the increased interfacial affinity between graphite oxide and hydrogel matrix. The fabricated micro heater was effective in controlling the temperature over lower critical solution temperature of hydrogel precisely with a small voltage less than 1 V. The cell viability test on graphite oxide composite hydrogel showed enough safety for using as a transdermal drug delivery patch. The performance of TDDS could be improved noticeably based on temperature-responsive hydrogel, thermally conductive graphite oxide, and efficient micro heater. - Graphical abstract: The high-performance transdermal drug delivery system could be prepared by combining temperature-responsive hydrogel, thermally conductive graphite oxide with improved interfacial affinity, and efficient micro heater fabricated by a joule heating method. Highlights: ► High performance of transdermal drug delivery system with an easy control of voltage. ► Improved thermal response of hydrogel by graphite oxide incorporation. ► Efficient micro heater fabricated by a joule heating method.

  8. Development of water packing mitigation scheme for MARS 3- dimensional thermal-hydraulic module

    Water packing mitigation scheme was developed to enhance the numerical stability and calculational efficiency of MARS 3-dimensional thermal-hydraulic module. The water packing phenomena is unphysical pressure spike which occurs in a two-phase system thermal-hydraulic code using Eulerian finite difference method. Great velocities developed from large pressure spike slow down the calculation efficiency due to the stability limit. Also, large pressure spike and subsequent low pressure can make errors in thermodynamic state table search. The developed water packing mitigation scheme was implemented in MARS3D module. It is shown from the results of some benchmark problema that numerical stability and calculational efficiency were improved

  9. Controlled Delivery of Vancomycin via Charged Hydrogels.

    Carl T Gustafson

    Full Text Available Surgical site infection (SSI remains a significant risk for any clean orthopedic surgical procedure. Complications resulting from an SSI often require a second surgery and lengthen patient recovery time. The efficacy of antimicrobial agents delivered to combat SSI is diminished by systemic toxicity, bacterial resistance, and patient compliance to dosing schedules. We submit that development of localized, controlled release formulations for antimicrobial compounds would improve the effectiveness of prophylactic surgical wound antibiotic treatment while decreasing systemic side effects. Our research group developed and characterized oligo(poly(ethylene glycolfumarate/sodium methacrylate (OPF/SMA charged copolymers as biocompatible hydrogel matrices. Here, we report the engineering of this copolymer for use as an antibiotic delivery vehicle in surgical applications. We demonstrate that these hydrogels can be efficiently loaded with vancomycin (over 500 μg drug per mg hydrogel and this loading mechanism is both time- and charge-dependent. Vancomycin release kinetics are shown to be dependent on copolymer negative charge. In the first 6 hours, we achieved as low as 33.7% release. In the first 24 hours, under 80% of total loaded drug was released. Further, vancomycin release from this system can be extended past four days. Finally, we show that the antimicrobial activity of released vancomycin is equivalent to stock vancomycin in inhibiting the growth of colonies of a clinically derived strain of methicillin-resistant Staphylococcus aureus. In summary, our work demonstrates that OPF/SMA hydrogels are appropriate candidates to deliver local antibiotic therapy for prophylaxis of surgical site infection.

  10. Agarose and methylcellulose hydrogel blends for nerve regeneration applications

    Martin, Benton C.; Minner, Eric J.; Wiseman, Sherri L.; Klank, Rebecca L.; Gilbert, Ryan J.

    2008-06-01

    Trauma sustained to the central nervous system is a debilitating problem for thousands of people worldwide. Neuronal regeneration within the central nervous system is hindered by several factors, making a multi-faceted approach necessary. Two factors contributing to injury are the irregular geometry of injured sites and the absence of tissue to hold potential nerve guides and drug therapies. Biocompatible hydrogels, injectable at room temperature, that rapidly solidify at physiological temperatures (37 °C) are beneficial materials that could hold nerve guidance channels in place and be loaded with therapeutic agents to aid wound healing. Our studies have shown that thermoreversible methylcellulose can be combined with agarose to create hydrogel blends that accommodate these properties. Three separate novel hydrogel blends were created by mixing methylcellulose with one of the three different agaroses. Gelation time tests show that the blends solidify at a faster rate than base methylcellulose at 37 °C. Rheological data showed that the elastic modulus of the hydrogel blends rapidly increases at 37 °C. Culturing experiments reveal that the morphology of dissociated dorsal root ganglion neurons was not altered when the hydrogels were placed onto the cells. The different blends were further assessed using dissolution tests, pore size evaluations using scanning electron microscopy and measuring the force required for injection. This research demonstrates that blends of agarose and methylcellulose solidify much more quickly than plain methylcellulose, while solidifying at physiological temperatures where agarose cannot. These hydrogel blends, which solidify at physiological temperatures naturally, do not require ultraviolet light or synthetic chemical cross linkers to facilitate solidification. Thus, these hydrogel blends have potential use in delivering therapeutics and holding scaffolding in place within the nervous system.