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Sample records for thermosensitive composite hydrogel

  1. Synthesis and characterization of injectable, thermosensitive, and biocompatible acellular bone matrix/poly(ethylene glycol)-poly (ε-caprolactone)-poly(ethylene glycol) hydrogel composite.

    Science.gov (United States)

    Ni, Pei-Yan; Fan, Min; Qian, Zhi-Yong; Luo, Jing-Cong; Gong, Chang-Yang; Fu, Shao-Zhi; Shi, Shuai; Luo, Feng; Yang, Zhi-Ming

    2012-01-01

    In orthopedic tissue engineering, the extensively applied acellular bone matrix (ABM) can seldom be prefabricated just right to mold the cavity of the diverse defects, might induce severe inflammation on account of the migration of small granules and usually bring the patients great pain in the treatment. In this study, a new injectable thermosensitive ABM/PECE composite with good biocompatibility was designed and prepared by adding the ABM granules into the triblock copolymer poly(ethylene eglycol)-poly(ε-caprolactone)-poly(ethylene eglycol) (PEG-PCL-PEG, PECE). The PECE was synthesized by ring-opening copolymerization and characterized by ¹H NMR. The ABM was prepared by acellular treatment of natural bone and ground to fine granules. The obtained ABM/PECE composite showed the most important absorption bands of ABM and PECE copolymer in FT-IR spectroscopy and underwent sol-gel phage transition from solution to nonflowing hydrogel at 37°C. SEM results indicated that the ABM/PECE composite with different ABM contents all presented similar porous 3D structure. ABM/PECE composite presented mild cytotoxicity to rat MSCs in vitro and good biocompatibility in the BALB/c mice subcutis up to 4 weeks. In conclusion, all the results confirmed that the injectable thermosensitive ABM/PECE composite was a promising candidate for orthopedic tissue engineering in a minimally-invasive way. Copyright © 2011 Wiley Periodicals, Inc.

  2. Radiation synthesis and characterization of thermo-sensitive PNIPA/clay hydrogels

    International Nuclear Information System (INIS)

    Song Hongyan; He Suqin; Liu Wentao; Zhu Chengshen; Yang Mingcheng

    2007-01-01

    In this work, the thermo-sensitive hydrogels of PNIPA/Clay were synthesized by 60 Co-γ rays irradiation. The effects of organically modified clay and Na + clay, clay content, and dispersing condition on swelling behavior of PNIPA/clay hydrogels were investigated. The results showed that the equilibrium swelling ratio (SR) of the PNIPA/clay hydrogels is better than PNIPA, and the SR of PNIPA/organically modified clay hydrogels is the highest. With clay content increases, the SR of hydrogels became better. The deswelling behavior of hydrogel was improved, the deswelling ratio of the hydrogel with organically modified clay is highest, and ratio of losing water is 83%, while PNIPA is about 50%. The compressive properties of hydrogel composites were also examined. The results showed that the compressive properties of the PNIPA/clay hydrogels were improved distinctly than that of the conventional hydrogels without clay. And with increasing of clay content, the compressive properties of hydrogel composites improve rapidly. When the content of clay is 15%, the maximum compression force of the PNIPA/clay hydrogel is 5.28N, which is 14 times of PNIPA hydrogel and compression strength is 2.5 times. (authors)

  3. Dynamic culture of a thermosensitive collagen hydrogel as an extracellular matrix improves the construction of tissue-engineered peripheral nerve.

    Science.gov (United States)

    Huang, Lanfeng; Li, Rui; Liu, Wanguo; Dai, Jin; Du, Zhenwu; Wang, Xiaonan; Ma, Jianchao; Zhao, Jinsong

    2014-07-15

    Tissue engineering technologies offer new treatment strategies for the repair of peripheral nerve injury, but cell loss between seeding and adhesion to the scaffold remains inevitable. A thermosensitive collagen hydrogel was used as an extracellular matrix in this study and combined with bone marrow mesenchymal stem cells to construct tissue-engineered peripheral nerve composites in vitro. Dynamic culture was performed at an oscillating frequency of 0.5 Hz and 35° swing angle above and below the horizontal plane. The results demonstrated that bone marrow mesenchymal stem cells formed membrane-like structures around the poly-L-lactic acid scaffolds and exhibited regular alignment on the composite surface. Collagen was used to fill in the pores, and seeded cells adhered onto the poly-L-lactic acid fibers. The DNA content of the bone marrow mesenchymal stem cells was higher in the composites constructed with a thermosensitive collagen hydrogel compared with that in collagen I scaffold controls. The cellular DNA content was also higher in the thermosensitive collagen hydrogel composites constructed with the thermosensitive collagen hydrogel in dynamic culture than that in static culture. These results indicate that tissue-engineered composites formed with thermosensitive collagen hydrogel in dynamic culture can maintain larger numbers of seeded cells by avoiding cell loss during the initial adhesion stage. Moreover, seeded cells were distributed throughout the material.

  4. Enhanced mechanical properties of thermosensitive chitosan hydrogel by silk fibers for cartilage tissue engineering

    International Nuclear Information System (INIS)

    Mirahmadi, Fereshteh; Tafazzoli-Shadpour, Mohammad; Shokrgozar, Mohammad Ali; Bonakdar, Shahin

    2013-01-01

    Articular cartilage has limited repair capability following traumatic injuries and current methods of treatment remain inefficient. Reconstructing cartilage provides a new way for cartilage repair and natural polymers are often used as scaffold because of their biocompatibility and biofunctionality. In this study, we added degummed chopped silk fibers and electrospun silk fibers to the thermosensitive chitosan/glycerophosphate hydrogels to reinforce two hydrogel constructs which were used as scaffold for hyaline cartilage regeneration. The gelation temperature and gelation time of hydrogel were analyzed by the rheometer and vial tilting method. Mechanical characterization was measured by uniaxial compression, indentation and dynamic mechanical analysis assay. Chondrocytes were then harvested from the knee joint of the New Zealand white rabbits and cultured in constructs. The cell proliferation, viability, production of glycosaminoglycans and collagen type II were assessed. The results showed that mechanical properties of the hydrogel were significantly enhanced when a hybrid with two layers of electrospun silk fibers was made. The results of GAG and collagen type II in cell-seeded scaffolds indicate support of the chondrogenic phenotype for chondrocytes with a significant increase in degummed silk fiber–hydrogel composite for GAG content and in two-layer electrospun fiber–hydrogel composite for Col II. It was concluded that these two modified scaffolds could be employed for cartilage tissue engineering. - Highlights: • Chitosan hydrogel composites fabricated by two forms of silk fiber • Silk fibers provide structural support for the hydrogel matrix. • The mechanical properties of hydrogel significantly improved by associating with silk. • Production of GAG and collagen type II was demonstrated within the scaffolds

  5. Enhanced mechanical properties of thermosensitive chitosan hydrogel by silk fibers for cartilage tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Mirahmadi, Fereshteh [Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); National Cell Bank of Iran, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of); Tafazzoli-Shadpour, Mohammad, E-mail: Tafazoli@aut.ac.ir [Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Shokrgozar, Mohammad Ali, E-mail: mashokrgozar@pasteur.ac.ir [National Cell Bank of Iran, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of); Bonakdar, Shahin [National Cell Bank of Iran, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of)

    2013-12-01

    Articular cartilage has limited repair capability following traumatic injuries and current methods of treatment remain inefficient. Reconstructing cartilage provides a new way for cartilage repair and natural polymers are often used as scaffold because of their biocompatibility and biofunctionality. In this study, we added degummed chopped silk fibers and electrospun silk fibers to the thermosensitive chitosan/glycerophosphate hydrogels to reinforce two hydrogel constructs which were used as scaffold for hyaline cartilage regeneration. The gelation temperature and gelation time of hydrogel were analyzed by the rheometer and vial tilting method. Mechanical characterization was measured by uniaxial compression, indentation and dynamic mechanical analysis assay. Chondrocytes were then harvested from the knee joint of the New Zealand white rabbits and cultured in constructs. The cell proliferation, viability, production of glycosaminoglycans and collagen type II were assessed. The results showed that mechanical properties of the hydrogel were significantly enhanced when a hybrid with two layers of electrospun silk fibers was made. The results of GAG and collagen type II in cell-seeded scaffolds indicate support of the chondrogenic phenotype for chondrocytes with a significant increase in degummed silk fiber–hydrogel composite for GAG content and in two-layer electrospun fiber–hydrogel composite for Col II. It was concluded that these two modified scaffolds could be employed for cartilage tissue engineering. - Highlights: • Chitosan hydrogel composites fabricated by two forms of silk fiber • Silk fibers provide structural support for the hydrogel matrix. • The mechanical properties of hydrogel significantly improved by associating with silk. • Production of GAG and collagen type II was demonstrated within the scaffolds.

  6. Enhanced mechanical properties of thermosensitive chitosan hydrogel by silk fibers for cartilage tissue engineering.

    Science.gov (United States)

    Mirahmadi, Fereshteh; Tafazzoli-Shadpour, Mohammad; Shokrgozar, Mohammad Ali; Bonakdar, Shahin

    2013-12-01

    Articular cartilage has limited repair capability following traumatic injuries and current methods of treatment remain inefficient. Reconstructing cartilage provides a new way for cartilage repair and natural polymers are often used as scaffold because of their biocompatibility and biofunctionality. In this study, we added degummed chopped silk fibers and electrospun silk fibers to the thermosensitive chitosan/glycerophosphate hydrogels to reinforce two hydrogel constructs which were used as scaffold for hyaline cartilage regeneration. The gelation temperature and gelation time of hydrogel were analyzed by the rheometer and vial tilting method. Mechanical characterization was measured by uniaxial compression, indentation and dynamic mechanical analysis assay. Chondrocytes were then harvested from the knee joint of the New Zealand white rabbits and cultured in constructs. The cell proliferation, viability, production of glycosaminoglycans and collagen type II were assessed. The results showed that mechanical properties of the hydrogel were significantly enhanced when a hybrid with two layers of electrospun silk fibers was made. The results of GAG and collagen type II in cell-seeded scaffolds indicate support of the chondrogenic phenotype for chondrocytes with a significant increase in degummed silk fiber-hydrogel composite for GAG content and in two-layer electrospun fiber-hydrogel composite for Col II. It was concluded that these two modified scaffolds could be employed for cartilage tissue engineering. © 2013.

  7. Thermosensitive copolymeric hydrogels with the regulated temperature of a phase transition

    International Nuclear Information System (INIS)

    Samchenko, Yu.M.; Konovalova, V.V.; Korotich, E.I.; Poltoratskaya, T.P.; Pobegaj, A.A.; Burban, A.F.; Ul'berg, Z.R.; Samchenko, Yu.M.; Konovalova, V.V.; Korotich, E.I.; Poltoratskaya, T.P.; Pobegaj, A.A.; Burban, A.F.; Ul'berg, Z.R.

    2011-01-01

    The work is devoted to the methods of obtaining the thermosensitive copolymeric hydrogels based on the NIPAAm with acrylic acid and its derivatives such as acrylamide, acrylonitrile, and methylacrylate. The mechanisms of thermoinitiated phase transitions in hydrogel matrices and the regularities of the thermoinitiated release of model compounds and drugs (aniline, novocaine, and sodium diclofenac) from copolymeric hydrogel are investigated.

  8. Novel thermosensitive hydrogel for preventing formation of abdominal adhesions

    Directory of Open Access Journals (Sweden)

    Gao X

    2013-07-01

    Full Text Available Xiang Gao,1,2 Xiaohui Deng,3 Xiawei Wei,2 Huashan Shi,2 Fengtian Wang,2 Tinghong Ye,2 Bin Shao,2 Wen Nie,2 Yuli Li,2 Min Luo,2 Changyang Gong,2 Ning Huang1 1Department of Pathophysiology, College of Preclinical and Forensic Medical Sciences, Sichuan University, Chengdu, 2State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, 3Department of Human Anatomy, Xinxiang Medical University, Xinxiang, People’s Republic of China Abstract: Adhesions can form after almost any type of abdominal surgery. Postoperative adhesions can be prevented by improved surgical techniques, such as reducing surgical trauma, preventing ischemia, and avoiding exposure of the peritoneal cavity to foreign materials. Although improved surgical techniques can potentially reduce formation of adhesions, they cannot be eliminated completely. Therefore, finding more effective methods to prevent postoperative adhesions is imperative. Recently, we found that a novel thermosensitive hydrogel, ie, poly(ε-caprolactone-poly(ethylene glycol-poly(ε-caprolactone (PCEC had the potential to prevent postoperative adhesions. Using the ring-opening polymerization method, we prepared a PCEC copolymer which could be dissolved and assembled at 55°C into PCEC micelles with mean size of 25 nm. At body temperature, a solution containing PCEC micelles could convert into a hydrogel. The PCEC copolymer was biodegradable and had low toxicity in vitro and in vivo. We found that most animals in a hydrogel-treated group (n = 10 did not develop adhesions. In contrast, 10 untreated animals developed adhesions that could only be separated by sharp dissection (P < 0.001. The hydrogel could adhere to peritoneal wounds and degraded gradually over 7–9 days, transforming into a viscous fluid that was completely absorbed within 12 days. The injured parietal and visceral peritoneum remesothelialized over about seven and nine days

  9. Injectable hydrogel as stem cell scaffolds from the thermosensitive terpolymer of NIPAAm/AAc/HEMAPCL

    Directory of Open Access Journals (Sweden)

    Lian S

    2012-09-01

    Full Text Available Sheng Lian,1Yan Xiao,1 Qingqing Bian,1Yu Xia,2 Changfa Guo,2 Shenguo Wang,2 Meidong Lang11Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, People's Republic of China; 2Department of Cardiac Surgery, Zhongshan Hospital, Fudan University and Shanghai Institute of Cardiovascular Diseases, Shanghai, People's Republic of ChinaAbstract: A series of biodegradable thermosensitive copolymers was synthesized by free radical polymerization with N-isopropylacrylamide (NIPAAm, acrylic acid (AAc and macromer 2-hydroxylethyl methacrylate-poly(ε-caprolactone (HEMAPCL. The structure and composition of the obtained terpolymers were confirmed by proton nuclear magnetic resonance spectroscopy, while their molecular weight was measured using gel permeation chromatography. The copolymers were dissolved in phosphate-buffered saline (PBS solution (pH = 7.4 with different concentrations to prepare hydrogels. The lower critical solution temperature (LCST, cloud point, and rheological property of the hydrogels were determined by differential scanning calorimetry, ultraviolet-visible spectrometry, and rotational rheometry, respectively. It was found that LCST of the hydrogel increased significantly with the increasing NIPAAm content, and hydrogel with higher AAc/HEMAPCL ratio exhibited better storage modulus, water content, and injectability. The hydrogels were formed by maintaining the copolymer solution at 37°C. The degradation experiment on the formed hydrogels was conducted in PBS solution for 2 weeks and demonstrated a less than 20% weight loss. Scanning electron microscopy was also used to study the morphology of the hydrogel. The copolymer with NIPAAm/AAc/HEMAPCL ratio of 88:9.6:2.4 was bioconjugated with type I collagen for the purpose of biocompatibility enhancement. In-vitro cytotoxicity

  10. Structural and biological properties of thermosensitive chitosan-graphene hybrid hydrogels for sustained drug delivery applications.

    Science.gov (United States)

    Saeednia, Leyla; Yao, Li; Berndt, Marcus; Cluff, Kim; Asmatulu, Ramazan

    2017-09-01

    Chitosan has the ability to make injectable thermosensitive hydrogels which has been highly investigated for drug delivery applications. The addition of nanoparticles is one way to increase the mechanical strength of thermosensitive chitosan hydrogel and subsequently and control the burst release of drug. Graphene nanoparticles have shown unique mechanical, optical and electrical properties which can be exploited for biomedical applications, especially in drug delivery. This study, have focused on the mechanical properties of a thermosensitive and injectable hybrid chitosan hydrogel incorporated with graphene nanoparticles. Scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and X-ray diffraction (XRD) have been used for morphological and chemical characterization of graphene infused chitosan hydrogels. The cell viability and cytotoxicity of graphene-contained hydrogels were analyzed using the alamarBlue ® technique. In-vitro methotrexate (MTX) release was investigated from MTX-loaded hybrid hydrogels as well. As a last step, to evaluate their efficiency as a cancer treatment delivery system, an in vitro anti-tumor test was also carried out using MCF-7 breast cancer cell lines. Results confirmed that a thermosensitive chitosan-graphene hybrid hydrogel can be used as a potential breast cancer therapy system for controlled delivery of methotrexate. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2381-2390, 2017. © 2017 Wiley Periodicals, Inc.

  11. Enhanced gelation of chitosan/β-sodium glycerophosphate thermosensitive hydrogel with sodium bicarbonate and biocompatibility evaluated.

    Science.gov (United States)

    Deng, Aipeng; Kang, Xi; Zhang, Jing; Yang, Yang; Yang, Shulin

    2017-09-01

    The application of chitosan/β-sodium glycerophosphate (β-GP) thermosensitive hydrogel has been limited by the relatively slow gelation, weak mechanical resistance and poor cytocompatibility. In this study, sodium hydrogen carbonate (NaHCO 3 ) was applied with β-GP as gel agents to produce high-strength hydrogel. The hydrogels prepared with high NaHCO 3 concentration or more gel agents showed shorter gelation time, better thermostability, drastically enhanced resistance in compression. Meanwhile, the hydrogels presented obvious porous structures and excellent biocompatibility to HUVEC and NIH 3T3 cultured in vitro with higher NaHCO 3 concentration and moderate concentration of β-GP. Overall, appropriate concentration of β-GP combined with NaHCO 3 can be a good gel regent to improve properties of chitosan thermosensitive hydrogels. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Fabrication and evaluation of thermosensitive chitosan/collagen/α, β-glycerophosphate hydrogels for tissue regeneration.

    Science.gov (United States)

    Dang, Qifeng; Liu, Kai; Zhang, Zhenzhen; Liu, Chengsheng; Liu, Xi; Xin, Ying; Cheng, Xiaoyu; Xu, Tao; Cha, Dongsu; Fan, Bing

    2017-07-01

    Thermosensitive hydrogels whose physiological properties are similar to extracellular matrix have been extensively used for tissue regeneration. Polysaccharides and proteins, as biocompatible substrates similar to bio-macromolecules that could be recognized by human body, are two preferred polymers for fabrication of such hydrogels. A series of novel thermosensitive hydrogels (CS-ASC-HGs) containing chitosan (CS) and acid-soluble collagen (ASC) were thus prepared, in the presence of α, β-glycerophosphate, to mimic extracellular microenvironment for tissue regeneration. Rheological measurements demonstrated excellent thermosensitivity. FT-IR and SEM indicated CS-ASC-HGs possessed 3D porous architectures with fibrous ASC, and the molecular structure of ASC was well-maintained in hydrogels. Hemolysis, acute toxicity, and cytotoxicity tests suggested CS-ASC-HGs were of good biocompatibility. CS-ASC-HGs were able to support the survival and proliferation of L929 cells encapsulated in them. Moreover, CS-ASC-HGs had better pH stability and biocompatibility than pure CS hydrogel. These results suggested that CS-ASC-HGs could serve as promising scaffolds for tissue regeneration. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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.

  14. Thermo-sensitive injectable glycol chitosan-based hydrogel for treatment of degenerative disc disease.

    Science.gov (United States)

    Li, Zhengzheng; Shim, Hyeeun; Cho, Myeong Ok; Cho, Ik Sung; Lee, Jin Hyun; Kang, Sun-Woong; Kwon, Bosun; Huh, Kang Moo

    2018-03-15

    The use of injectable hydrogel formulations have been suggested as a promising strategy for the treatment of degenerative disc disease to both restore the biomechanical function and reduce low back pain. In this work, a new thermo-sensitive injectable hydrogels with tunable thermo-sensitivity and enhanced stability were developed with N-hexanoylation of glycol chitosan (GC) for treatment of degenerative disc disease, and their physico-chemical and biological properties were evaluated. The sol-gel transition temperature of the hydrogels was controlled in a range of 23-56 °С, depending on the degree of hexanoylation and the polymer concentration. In vitro and in vivo tests showed no cytotoxicity and no adverse effects in a rat model. The hydrogel filling of the defective IVD site in an ex vivo porcine model maintained its stability for longer than 28 days. These results suggest that the hydrogel can be used as an alternative material for treatment of disc herniation. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Two-component thermosensitive hydrogels : Phase separation affecting rheological behavior

    NARCIS (Netherlands)

    Abbadessa, Anna; Landín, Mariana; Oude Blenke, Erik; Hennink, Wim E.; Vermonden, Tina

    2017-01-01

    Extracellular matrices are mainly composed of a mixture of different biopolymers and therefore the use of two or more building blocks for the development of tissue-mimicking hydrogels is nowadays an attractive strategy in tissue-engineering. Multi-component hydrogel systems may undergo phase

  16. Highly Flexible, Multipixelated Thermosensitive Smart Windows Made of Tough Hydrogels.

    Science.gov (United States)

    La, Thanh-Giang; Li, Xinda; Kumar, Amit; Fu, Yiyang; Yang, Shu; Chung, Hyun-Joong

    2017-09-27

    In a cold night, a clear window that will become opaque while retaining the indoor heat is highly desirable for both privacy and energy efficiency. A thermally responsive material that controls both the transmittance of solar radiance (predominantly in the visible and near-infrared wavelengths) and blackbody radiation (mainly in the mid-infrared) can realize such windows with minimal energy consumption. Here, we report a smart coating made from polyampholyte hydrogel (PAH) that transforms from a transparency state to opacity to visible radiation and strengthens opacity to mid-infrared when lowering the temperature as a result of phase separation between the water-rich and polymer-rich phases. To match a typical temperature fluctuation during the day, we fine-tune the phase transition temperature between 25 and 55 °C by introducing a small amount of relatively hydrophobic monomers (0.1 to 0.5 wt % to PAH). To further demonstrate an actively controlled, highly flexible, and high-contrast smart window, we build in an array of electric heaters made of printed elastomeric composite. The multipixelated window offers rapid switching, ∼70 s per cycle, whereas the device can withstand high strain (up to 80%) during operations.

  17. Electrically conductive gold nanoparticle-chitosan thermosensitive hydrogels for cardiac tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Baei, Payam [Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran (Iran, Islamic Republic of); Cardiovascular Engineering Laboratory, Faculty of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran (Iran, Islamic Republic of); Jalili-Firoozinezhad, Sasan [Department of Biomedicine and Surgery, University Hospital Basel, University of Basel, Hebelstrasse 20, CH-4031 Basel (Switzerland); Department of Bioengineeringand IBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa (Portugal); Rajabi-Zeleti, Sareh [Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran (Iran, Islamic Republic of); Tafazzoli-Shadpour, Mohammad [Cardiovascular Engineering Laboratory, Faculty of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran (Iran, Islamic Republic of); Baharvand, Hossein, E-mail: Baharvand@royaninstitute.org [Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran (Iran, Islamic Republic of); Department of Developmental Biology, University of Science and Culture, ACECR, Tehran (Iran, Islamic Republic of); Aghdami, Nasser, E-mail: Nasser.Aghdami@royaninstitute.org [Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran (Iran, Islamic Republic of)

    2016-06-01

    Injectable hydrogels that resemble electromechanical properties of the myocardium are crucial for cardiac tissue engineering prospects. We have developed a facile approach that uses chitosan (CS) to generate a thermosensitive conductive hydrogel with a highly porous network of interconnected pores. Gold nanoparticles (GNPs) were evenly dispersed throughout the CS matrix in order to provide electrical cues. The gelation response and electrical conductivity of the hydrogel were controlled by different concentrations of GNPs. The CS-GNP hydrogels were seeded with mesenchymal stem cells (MSCs) and cultivated for up to 14 days in the absence of electrical stimulations. CS-GNP scaffolds supported viability, metabolism, migration and proliferation of MSCs along with the development of uniform cellular constructs. Immunohistochemistry for early and mature cardiac markers showed enhanced cardiomyogenic differentiation of MSCs within the CS-GNP compared to the CS matrix alone. The results of this study demonstrate that incorporation of nanoscale electro-conductive GNPs into CS hydrogels enhances the properties of myocardial constructs. These constructs could find utilization for regeneration of other electroactive tissues. - Highlights: • Thermosensitive electro-conductive hydrogels were prepared from CS and GNPs. • Gelation time and conductivity were tuned by varying concentration of GNPs. • CS-2GNP with gelation time of 25.7 min and conductivity of 0.13 S·m{sup −1} was selected for in vitro studies. • CS-2GNP supported active metabolism, migration and proliferation of MSCs. • Expression of cardiac markers increased about two-fold in CS-2GNP compared to CS.

  18. Electrically conductive gold nanoparticle-chitosan thermosensitive hydrogels for cardiac tissue engineering

    International Nuclear Information System (INIS)

    Baei, Payam; Jalili-Firoozinezhad, Sasan; Rajabi-Zeleti, Sareh; Tafazzoli-Shadpour, Mohammad; Baharvand, Hossein; Aghdami, Nasser

    2016-01-01

    Injectable hydrogels that resemble electromechanical properties of the myocardium are crucial for cardiac tissue engineering prospects. We have developed a facile approach that uses chitosan (CS) to generate a thermosensitive conductive hydrogel with a highly porous network of interconnected pores. Gold nanoparticles (GNPs) were evenly dispersed throughout the CS matrix in order to provide electrical cues. The gelation response and electrical conductivity of the hydrogel were controlled by different concentrations of GNPs. The CS-GNP hydrogels were seeded with mesenchymal stem cells (MSCs) and cultivated for up to 14 days in the absence of electrical stimulations. CS-GNP scaffolds supported viability, metabolism, migration and proliferation of MSCs along with the development of uniform cellular constructs. Immunohistochemistry for early and mature cardiac markers showed enhanced cardiomyogenic differentiation of MSCs within the CS-GNP compared to the CS matrix alone. The results of this study demonstrate that incorporation of nanoscale electro-conductive GNPs into CS hydrogels enhances the properties of myocardial constructs. These constructs could find utilization for regeneration of other electroactive tissues. - Highlights: • Thermosensitive electro-conductive hydrogels were prepared from CS and GNPs. • Gelation time and conductivity were tuned by varying concentration of GNPs. • CS-2GNP with gelation time of 25.7 min and conductivity of 0.13 S·m"−"1 was selected for in vitro studies. • CS-2GNP supported active metabolism, migration and proliferation of MSCs. • Expression of cardiac markers increased about two-fold in CS-2GNP compared to CS.

  19. The effect of hypoxia on thermosensitive poly(N-vinylcaprolactam) hydrogels with tunable mechanical integrity for cartilage tissue engineering.

    Science.gov (United States)

    Lynch, Brandon; Crawford, Kristopher; Baruti, Omari; Abdulahad, Asem; Webster, Martial; Puetzer, Jennifer; Ryu, Chang; Bonassar, Lawrence J; Mendenhall, Juana

    2017-10-01

    Cartilage repair presents a daunting challenge in tissue engineering applications due to the low oxygen conditions (hypoxia) affiliated in diseased states. Hence, the use of biomaterial scaffolds with unique variability is imperative to treat diseased or damaged cartilage. Thermosensitive hydrogels show promise as injectable materials that can be used as tissue scaffolds for cartilage tissue regeneration. However, uses in clinical applications are limited to due mechanical stability and therapeutic efficacy to treat diseased tissue. In this study, several composite hydrogels containing poly(N-vinylcaprolactam) (PVCL) and methacrylated hyaluronic acid (meHA) were prepared using free radical polymerization to produce PVCL-graft-HA (PVCL-g-HA) and characterized using Fourier transform infrared spectroscopy, nuclear magnetic resonance, and scanning electron microscopy. Lower critical solution temperatures and gelation temperatures were confirmed in the range of 33-34°C and 41-45°C, respectively. Using dynamic sheer rheology, the temperature dependence of elastic (G') and viscous (G″) modulus between 25°C and 45°C, revealed that PVCL-g-HA hydrogels at 5% (w/v) concentration exhibited the moduli of 7 Pa (G') to 4 Pa (G″). After 10 days at 1% oxygen, collagen production on PVCL-g-HA hydrogels was 153 ± 25 μg/mg (20%) and 106 ± 18 μg/mg showing a 10-fold increase compared to meHA controls. These studies show promise in PVCL-g-HA hydrogels for the treatment of diseased or damaged articular cartilage. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1863-1873, 2017. © 2016 Wiley Periodicals, Inc.

  20. Intra-articular Administration of Chitosan Thermosensitive In Situ Hydrogels Combined With Diclofenac Sodium-Loaded Alginate Microspheres.

    Science.gov (United States)

    Qi, Xiaole; Qin, Xiaoxue; Yang, Rong; Qin, Jiayi; Li, Wenyan; Luan, Kun; Wu, Zhenghong; Song, Li

    2016-01-01

    The aims of this study were to prepare fine intra-articular-administrated chitosan thermosensitive hydrogels combined with alginate microspheres and to investigate the possibility of those hydrogels as a drug delivery system for promoting the anti-inflammation effect. Diclofenac sodium containing alginate microspheres was prepared by a modified emulsification and/or gelation method and then dispersed into injectable thermosensitive hydrogels, consisting of chitosan and β-glycerophosphate. The final combined hydrogels were evaluated in terms of their morphology properties, rheological properties, in vitro drug release, and in vivo biocompatibility and pharmacodynamics behaviors. The optimized formulation exhibited sol-gel transition at 31.72 ± 0.42°C and quickly turned into gel within 5 min, with sustained drug release characteristics followed Ritger-Peppas equation, which could prolong the in vitro drug release to 5 days. In addition, the anti-inflammation efficacy of the combined hydrogels in rabbits with experimental rheumatoid arthritis was higher than that of drug solution and pure chitosan hydrogels. Those results demonstrated that these combined hydrogels could become a potential drug delivery system for improving the therapeutic effect of diclofenac sodium and suggested an important technology platform for intra-articular administration. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  1. A novel vehicle for local protein delivery to the inner ear: injectable and biodegradable thermosensitive hydrogel loaded with PLGA nanoparticles.

    Science.gov (United States)

    Dai, Juan; Long, Wei; Liang, Zhongping; Wen, Lu; Yang, Fan; Chen, Gang

    2018-01-01

    Delivery of biomacromolecular drugs into the inner ear is challenging, mainly because of their inherent instability as well as physiological and anatomical barriers. Therefore, protein-friendly, hydrogel-based delivery systems following local administration are being developed for inner ear therapy. Herein, biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) containing interferon α-2 b (IFN α-2 b) were loaded in chitosan/glycerophosphate (CS/GP)-based thermosensitive hydrogel for IFN delivery by intratympanic injection. The injectable hydrogel possessed a physiological pH and formed semi-solid gel at 37 °C, with good swelling and deswelling properties. The CS/GP hydrogel could slowly degrade as visualized by scanning electron microscopy (SEM). The presence of NPs in CS/GP gel largely influenced in vitro drug release. In the guinea pig cochlea, a 1.5- to 3-fold increase in the drug exposure time of NPs-CS/GP was found than those of the solution, NPs and IFN-loaded hydrogel. Most importantly, a prolonged residence time was attained without obvious histological changes in the inner ear. This biodegradable, injectable, and thermosensitive NPs-CS/GP system may allow longer delivery of protein drugs to the inner ear, thus may be a potential novel vehicle for inner ear therapy.

  2. Thermosensitive Behavior and Antibacterial Activity of Cotton Fabric Modified with a Chitosan-poly(N-isopropylacrylamide Interpenetrating Polymer Network Hydrogel

    Directory of Open Access Journals (Sweden)

    Boxiang Wang

    2016-03-01

    Full Text Available To increase the themosensitive behavior and antibacterial activity of cotton fabric, a series of poly (N-isopropylacrylamide/chitosan (PNIPAAm/Cs hydrogels was synthesized by interpenetrating polymer network (IPN technology using a redox initiator. The IPN PNIPAAm/Cs hydrogel was characterized by Fourier transform infrared spectroscopy (FT-IR, differential scanning calorimetry (DSC, and thermogravimetric analysis (TGA. The results indicated that the IPN PNIPAAm/Cs hydrogel has a lower critical solution temperature (LCST at 33 °C. The IPN hydrogel was then used to modify cotton fabric using glutaric dialdehyde (GA as a crosslinking agent following a double-dip-double-nip process. The results demonstrated that the modified cotton fabric showed obvious thermosensitive behavior and antibacterial activity. The contact angle of the modified cotton fabric has a sharp rise around 33 °C, and the modified cotton fabric showed an obvious thermosensitive behavior. The bacterial reduction of modified cotton fabric against Staphylococcus aureus (S. aureus and Escherichia coli (E. coli were more than 99%. This study presents a valuable route towards smart textiles and their applications in functional clothing.

  3. Evaluation of a novel biodegradable thermosensitive keto-hydrogel for improving postoperative pain in a rat model.

    Science.gov (United States)

    Wu, Meng-Huang; Shih, Ming-Hung; Hsu, Wei-Bin; Dubey, Navneet Kumar; Lee, Wen-Fu; Lin, Tsai-Yu; Hsieh, Meng-Yow; Chen, Chin-Fu; Peng, Kuo-Ti; Huang, Tsung-Jen; Shi, Chung-Sheng; Guo, Ren-Shyang; Cai, Chang-Jhih; Chung, Chiu-Yen; Wong, Chung-Hang

    2017-01-01

    This study evaluates the sustained analgesic effect of ketorolac-eluting thermosensitive biodegradable hydrogel in the plantar incisional pain model of the rat hind-paw. A ketorolac-embedded 2, 2'-Bis (2-oxazolin) (BOX) linking methoxy-poly(ethylene glycol) and poly(lactide-co-glycolide) (mPEG-PLGA) diblock copolymer (BOX copolymer) was synthesized as keto-hydrogel based on optimal sol-gel phase transition and in vitro drug release profile. The effect of keto-hydrogel on postoperative pain (POP) was assessed using the established plantar incisional pain model in hind-paw of rats and compared to that of ketorolac solution. Pain and sensory threshold, as well as pain scoring, were evaluated with behavioral tests by means of anesthesiometer and incapacitance apparatus, respectively. Pro-inflammatory cytokine levels (TNF-α, IL-6, VEGF, and IL-1β) around incisional wounds were measured by ELISA. Tissue histology was assessed using hematoxylin and eosin and Masson's trichrome staining. Ten mg/mL (25 wt%) keto-hydrogel showed a sol-gel transition at 26.4°C with a 10-day sustained drug release profile in vitro. Compared to ketorolac solution group, the concentration of ketorolac in tissue fluid was higher in the keto-hydrogel group during the first 18 h of application. Keto-hydrogel elevated pain and sensory threshold, increased weight-bearing capacity, and significantly reduced the levels of TNF-α, IL-6, and IL-1β while enhanced VEGF in tissue fluid. Histologic analysis reveals greater epithelialization and collagen deposition around wound treated with keto-hydrogel. In conclusion, our study suggests that keto-hydrogel is an ideal compound to treat POP with a secondary gain of improved incisional wound healing.

  4. Evaluation of a novel biodegradable thermosensitive keto-hydrogel for improving postoperative pain in a rat model.

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    Meng-Huang Wu

    Full Text Available This study evaluates the sustained analgesic effect of ketorolac-eluting thermosensitive biodegradable hydrogel in the plantar incisional pain model of the rat hind-paw. A ketorolac-embedded 2, 2'-Bis (2-oxazolin (BOX linking methoxy-poly(ethylene glycol and poly(lactide-co-glycolide (mPEG-PLGA diblock copolymer (BOX copolymer was synthesized as keto-hydrogel based on optimal sol-gel phase transition and in vitro drug release profile. The effect of keto-hydrogel on postoperative pain (POP was assessed using the established plantar incisional pain model in hind-paw of rats and compared to that of ketorolac solution. Pain and sensory threshold, as well as pain scoring, were evaluated with behavioral tests by means of anesthesiometer and incapacitance apparatus, respectively. Pro-inflammatory cytokine levels (TNF-α, IL-6, VEGF, and IL-1β around incisional wounds were measured by ELISA. Tissue histology was assessed using hematoxylin and eosin and Masson's trichrome staining. Ten mg/mL (25 wt% keto-hydrogel showed a sol-gel transition at 26.4°C with a 10-day sustained drug release profile in vitro. Compared to ketorolac solution group, the concentration of ketorolac in tissue fluid was higher in the keto-hydrogel group during the first 18 h of application. Keto-hydrogel elevated pain and sensory threshold, increased weight-bearing capacity, and significantly reduced the levels of TNF-α, IL-6, and IL-1β while enhanced VEGF in tissue fluid. Histologic analysis reveals greater epithelialization and collagen deposition around wound treated with keto-hydrogel. In conclusion, our study suggests that keto-hydrogel is an ideal compound to treat POP with a secondary gain of improved incisional wound healing.

  5. Extremely stretchable thermosensitive hydrogels by introducing slide-ring polyrotaxane cross-linkers and ionic groups into the polymer network

    Science.gov (United States)

    Bin Imran, Abu; Esaki, Kenta; Gotoh, Hiroaki; Seki, Takahiro; Ito, Kohzo; Sakai, Yasuhiro; Takeoka, Yukikazu

    2014-01-01

    Stimuli-sensitive hydrogels changing their volumes and shapes in response to various stimulations have potential applications in multiple fields. However, these hydrogels have not yet been commercialized due to some problems that need to be overcome. One of the most significant problems is that conventional stimuli-sensitive hydrogels are usually brittle. Here we prepare extremely stretchable thermosensitive hydrogels with good toughness by using polyrotaxane derivatives composed of α-cyclodextrin and polyethylene glycol as cross-linkers and introducing ionic groups into the polymer network. The ionic groups help the polyrotaxane cross-linkers to become well extended in the polymer network. The resulting hydrogels are surprisingly stretchable and tough because the cross-linked α-cyclodextrin molecules can move along the polyethylene glycol chains. In addition, the polyrotaxane cross-linkers can be used with a variety of vinyl monomers; the mechanical properties of the wide variety of polymer gels can be improved by using these cross-linkers. PMID:25296246

  6. Alginate-Collagen Fibril Composite Hydrogel

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    Mahmoud Baniasadi

    2015-02-01

    Full Text Available We report on the synthesis and the mechanical characterization of an alginate-collagen fibril composite hydrogel. Native type I collagen fibrils were used to synthesize the fibrous composite hydrogel. We characterized the mechanical properties of the fabricated fibrous hydrogel using tensile testing; rheometry and atomic force microscope (AFM-based nanoindentation experiments. The results show that addition of type I collagen fibrils improves the rheological and indentation properties of the hydrogel.

  7. Heparin-Poloxamer Thermosensitive Hydrogel Loaded with bFGF and NGF Enhances Peripheral Nerve Regeneration in Diabetic Rats.

    Science.gov (United States)

    Li, Rui; Li, Yiyang; Wu, Yanqing; Zhao, Yingzheng; Chen, Huanwen; Yuan, Yuan; Xu, Ke; Zhang, Hongyu; Lu, Yingfeng; Wang, Jian; Li, Xiaokun; Jia, Xiaofeng; Xiao, Jian

    2018-06-01

    Peripheral nerve injury (PNI) is a major burden to society with limited therapeutic options, and novel biomaterials have great potential for shifting the current paradigm of treatment. With a rising prevalence of chronic illnesses such as diabetes mellitus (DM), treatment of PNI is further complicated, and only few studies have proposed therapies suitable for peripheral nerve regeneration in DM. To provide a supportive environment to restore structure and/or function of nerves in DM, we developed a novel thermo-sensitive heparin-poloxamer (HP) hydrogel co-delivered with basic fibroblast growth factor (bFGF) and nerve growth factor (NGF) in diabetic rats with sciatic nerve crush injury. The delivery vehicle not only had a good affinity for large amounts of growth factors (GFs), but also controlled their release in a steady fashion, preventing degradation in vitro. In vivo, compared with HP hydrogel alone or direct GFs administration, GFs-HP hydrogel treatment is more effective at facilitating Schwann cell (SC) proliferation, leading to an increased expression of nerve associated structural proteins, enhanced axonal regeneration and remyelination, and improved recovery of motor function (all p nerve regeneration in patients with DM. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Co-micellized Pluronic mixture with thermo-sensitivity and residence stability as an injectable tissue adhesion barrier hydrogel.

    Science.gov (United States)

    Oh, Se Heang; Kang, Jun Goo; Lee, Jin Ho

    2018-01-01

    Although the tissue adhesion which leads to various complications frequently occurs after surgery, the development of an ideal tissue adhesion barrier is still a challenge. In this study, a thermo-sensitive hydrogel, which can fulfill the essential requirements of tissue adhesion barrier (that is, ease of handling for surgeon, flowing down prevention after application, stable residence on the injury during wound healing, and no use of toxic additives), was developed using biocompatible polyethylene glycol-polypropylene glycol copolymers (Pluronic F127/F68/P123 mixture). From the in vitro cell culture and in vivo animal study, it was observed that the Pluronic mixtures showed sol-gel transition at approximately body temperature (for easy injection or coating on the injury site and flowing down prevention after application) and prolonged residence stability in aqueous environment (> ∼7 days for stable protection of injury tissues/organs during wound healing), and thus was highly effective for the prevention of tissue adhesion without adverse tissue responses. Based on these results, the Pluronic F127/F68/P123 mixture itself (without any additives) can be a good candidate as an injectable or coatable tissue adhesion barrier hydrogel applicable to various injury tissues in terms of ease of use, effectiveness, and safety. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 172-182, 2018. © 2016 Wiley Periodicals, Inc.

  9. Thermosensitive hydrogel based on chitosan and its derivatives containing medicated nanoparticles for transcorneal administration of 5-fluorouracil

    Directory of Open Access Journals (Sweden)

    Fabiano A

    2017-01-01

    Full Text Available Angela Fabiano,1 Ranieri Bizzarri,2 Ylenia Zambito1 1Department of Pharmacy, University of Pisa, 2NEST, Istituto Nanoscienze CNR (CNR-NANO and Scuola Normale Superiore, Pisa, Italy Abstract: A thermosensitive ophthalmic hydrogel (TSOH – fluid at 4°C (instillation temperature, semisolid at 35°C (eye temperature, which coupled the dosing accuracy and administration ease of eyedrops with the increased ocular bioavailability of a hydrogel – was prepared by gelling a chitosan hydrochloride (ChHCl solution (27.8 mg/mL medicated with 1.25 mg/mL 5-fluorouracil (5-FU with β-glycerophosphate 0.8 mg/mL. Polymer mixtures, where Ch was partially (10%, 15%, or 20% replaced by quaternary ammonium–chitosan conjugates (QA-Ch or thiolated derivatives thereof, were also used to modulate 5-FU-release properties of TSOH. Also, Ch-based nanoparticles (NPs; size after lyophilization and redispersion 341.5±15.2 nm, polydispersity 0.315±0.45, ζ-potential 10.21 mV medicated with 1.25 mg/mL 5-FU prepared by ionotropic cross-linking of Ch with hyaluronan were introduced into TSOH. The 5-FU binding by TSOH polymers in the sol state was maximum with plain Ch (31.4% and tended to decrease with increasing QA presence in polymer mixture. 5-FU release from TSOH with or without NPs was diffusion-controlled and linear in √t. The different TSOH polymers were compared on a diffusivity basis by comparing the slopes of √t plots. These showed a general decrease with NP-containing TSOH, which was the most marked with the TSOH, where Ch was 20% replaced by the derivative QA-Ch50. This formulation and that not containing NP were instilled in rabbits and the 5-FU transcorneal penetration was measured by analyzing the aqueous humor. Both TSOH solutions increased the area under the curve (0–8 hours 3.5 times compared with the plain eyedrops, but maximum concentration for the NP-free TSOH was about 0.65 µg/mL, followed by a slow decline, while the NP-containing one showed a

  10. Synthesis and characterization of thermosensitive hydrogels and the investigation of modified release of ibuprofen

    Directory of Open Access Journals (Sweden)

    Ilić-Stojanović Snežana S.

    2013-01-01

    Full Text Available The method of the synthesis of poly(N-isopropylacrylamide-co-2-hydroxypropyl methacrylate hydrogels obtained by radical polymerization is described. Their characterization was carried out by the determination of the quantity of residual monomers and by investigating their structure using the FTIR. Three glass transitions were detected by DSC method. The porous surfaces of hydrogels with incorporated ibuprofen were shown in SEM micrographs. The swelling ratio of hydrogels decreased with the temperature increase and the swelling transport mechanism was changed from non-Fickian to Fickian. Ibuprofen was incorporated in hydrogel as a drug carrier and released quantity was monitored by HPLC method depending on the temperature. Hydrogel with the lower cross-linker content had the highest swelling degree (α = 34.72 at 10°C and released the largest amount of ibuprofen (64.21 mg/gxerogel at 40°C. [Projekat Ministarstva nauke Republike Srbije, br. TR-34012

  11. Strengthening injectable thermo-sensitive NIPAAm-g-chitosan hydrogels using chemical cross-linking of disulfide bonds as scaffolds for tissue engineering.

    Science.gov (United States)

    Wu, Shu-Wei; Liu, Xifeng; Miller, A Lee; Cheng, Yu-Shiuan; Yeh, Ming-Long; Lu, Lichun

    2018-07-15

    In the present study, we fabricated non-toxic, injectable, and thermo-sensitive NIPAAm-g-chitosan (NC) hydrogels with thiol modification for introduction of disulfide cross-linking strategy. Previously, NIPAAm and chitosan copolymer has been proven to have excellent biocompatibility, biodegradability and rapid phase transition after injection, suitable to serve as cell carriers or implanted scaffolds. However, weak mechanical properties significantly limit their potential for biomedical fields. In order to overcome this issue, we incorporated thiol side chains into chitosan by covalently conjugating N-acetyl-cysteine (NAC) with carbodiimide chemistry to strengthen mechanical properties. After oxidation of thiols into disulfide bonds, modified NC hydrogels did improve the compressive modulus over 9 folds (11.4 kPa). Oscillatory frequency sweep showed a positive correlation between storage modulus and cross-liking density as well. Additionally, there was no cytotoxicity observed to mesenchymal stem cells, fibroblasts and osteoblasts. We suggested that the thiol-modified thermo-sensitive polysaccharide hydrogels are promising to be a cell-laden biomaterial for tissue regeneration. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Bioprinted chitosan-gelatin thermosensitive hydrogels using an inexpensive 3D printer.

    Science.gov (United States)

    Roehm, Kevin D; Madihally, Sundararajan V

    2017-11-30

    The primary bottleneck in bioprinting cell-laden structures with carefully controlled spatial relation is a lack of biocompatible inks and printing conditions. In this regard, we explored using thermogelling chitosan-gelatin (CG) hydrogel as a novel bioprinting ink; CG hydrogels are unique in that it undergoes a spontaneous phase change at physiological temperature, and does not need post-processing. In addition, we used a low cost (printer, and modified with a new extruder to print using disposable syringes and hypodermic needles. We investigated (i) the effect of concentration of CG on gelation characteristics, (ii) solution preparation steps (centrifugation, mixing, and degassing) on printability and fiber formation, (iii) the print bed temperature profiles via IR imaging and grid-based assessment using thermocouples, (iv) the effect of feed rate (10-480 cm min -1 ), flow rate (15-60 μl min -1 ) and needle height (70-280 μm) on fiber size and characteristics, and (v) the distribution of neuroblastoma cells in printed fibers, and the viability after five days in culture. We used agarose gel to create uniform print surfaces to maintain a constant gap with the needle tip. These results showed that degassing the solution, and precooling the solution was necessary for obtaining continuous fibers. Fiber size decreased from 760, to 243 μm as the feed rate increased from 10 to 100 cm min -1 . Bed temperature played the greatest role in fiber size, followed by feed rate. Increased needle height initially decreased fiber size but then increased showing an optimum. Cells were well distributed within the fibers and exhibited excellent viability and no contamination after 5 d. Overall we printed 3D, sterile, cell-laden structures with an inexpensive bioprinter and a novel ink, without post-processing. The bioprinter described here and the novel CG hydrogels have significant potential as an ink for bioprinitng various cell-laden structures.

  13. Thermosensitive Hydrogel Mask Significantly Improves Skin Moisture and Skin Tone; Bilateral Clinical Trial

    Directory of Open Access Journals (Sweden)

    Anna Quattrone

    2017-06-01

    Full Text Available Objective: A temperature-sensitive state-changing hydrogel mask was used in this study. Once it comes into contact with the skin and reaches the body temperature, it uniformly and quickly releases the active compounds, which possess moisturizing, anti-oxidant, anti-inflammatory and regenerative properties. Methods: An open label clinical trial was conducted to evaluate the effects of the test product on skin hydration, skin tone and skin ageing. Subjects applied the product to one side of their face and underwent Corneometer® and Chromameter measurements, Visual assessment of facial skin ageing and facial photography. All assessments and Self-Perception Questionnaires (SPQ were performed at baseline, after the first application of the test product and after four applications. Results: After a single treatment we observed an increase in skin moisturisation, an improvement of skin tone/luminosity and a reduction in signs of ageing, all statistically significant. After four applications a further improvement in all measured parameters was recorded. These results were confirmed by the subjects’ own perceptions, as reported in the SPQ both after one and four applications. Conclusion: The hydrogel mask tested in this study is very effective in improving skin hydration, skin radiance and luminosity, in encouraging an even skin tone and in reducing skin pigmentation.

  14. Therapeutic application of injectable thermosensitive hydrogel in preventing local breast cancer recurrence and improving incision wound healing in a mouse model

    Science.gov (United States)

    Lei, Na; Gong, Changyang; Qian, Zhiyong; Luo, Feng; Wang, Cheng; Wang, Helan; Wei, Yuquan

    2012-08-01

    Many drug delivery systems (DDSs) have been investigated for local targeting of malignant disease with the intention of increasing anti-tumor activity and minimizing systemic toxicity. An injectable thermosensitive hydrogel was applied to prevent locoregional recurrence of 4T1 breast cancer in a mouse model. The presented hydrogel, which is based on poly(ethyleneglycol)-poly(ε-caprolactone)-poly(ethylene glycol) (PEG-PCL-PEG, PECE), flows freely at normal temperature, forms a gel within seconds in situ at body temperature, and eventually releases the drug in a consistent and sustained fashion as it gradually biodegrades. Locoregional recurrence after primary tumor removal was significantly inhibited in mice treated with the paclitaxel (PTX)-loaded PECE hydrogel subcutaneously (9.1%) administered, compared with the blank hydrogel (80.0%), systemic (77.8%) and locally (75.0%) administered PTX, and the control group (100%) (P 0.05), in agreement with histopathological examinations. This novel DDSs represents a promising approach for local adjuvant therapy in malignant disease.

  15. Novel dual-reverse thermosensitive solid lipid nanoparticle-loaded hydrogel for rectal administration of flurbiprofen with improved bioavailability and reduced initial burst effect.

    Science.gov (United States)

    Din, Fakhar Ud; Mustapha, Omer; Kim, Dong Wuk; Rashid, Rehmana; Park, Jong Hyuck; Choi, Ju Yeon; Ku, Sae Kwang; Yong, Chul Soon; Kim, Jong Oh; Choi, Han-Gon

    2015-08-01

    The purpose of this study was to develop novel solid lipid nanoparticle (SLN)-loaded dual-reverse thermosensitive hydrogel (DRTH) for rectal administration of flurbiprofen with improved bioavailability and reduced initial burst effect. The flurbiprofen-loaded SLNs were prepared by hot homogenisation technique, after optimising the amounts of lipid mixture (tricaprin and triethanolamine in 8:2 weight ratio), drug and surfactant. The flurbiprofen-loaded thermosensitive SLN composed of drug, lipid mixture and surfactant at a weight ratio of 10/15/1.3 was a solid at room temperature, and changed to liquid form at physiological temperature due to its melting point of about 32°C. This SLN gave the mean particle size of about 190nm and entrapment efficiency of around 90%. The DRTHs were prepared by adding this flurbiprofen-loaded thermosensitive SLN in various poloxamer solutions. Their rheological characterisation, release and stability were investigated while a morphological and pharmacokinetic study was performed after its rectal administration to rats compared with the drug and hydrogel. Poloxamer 188 and SLN decreased the gelation temperature and gelation time, but increased the viscosity at 25°C, gel strength and mucoadhesive force of DRTHs. In particular, the DRTH composed of [SLN/P 407/P 188 (10%/15%/25%)] with the gelation temperature of about 35°C existed as liquid at room temperature, but gelled at 30-36°C, leading to opposite reversible property of SLN. Thus, it was easy to administer rectally, and it gelled rapidly inside the body. This DRTH gave a significantly increased dissolution rate of the drug as compared to the flurbiprofen, but significantly retarded as compared to the hydrogel, including the initial dissolution rate. Moreover, this DRTH gave significantly higher plasma concentration and 7.5-fold AUC values compared to the drug, and lower initial plasma concentration and Cmax value compared to the hydrogel due to reduced initial burst effect. No

  16. Development of hydrogels composites for potential use as biomaterials

    International Nuclear Information System (INIS)

    Silva, Gabriela T. da; Alves, Natali O.; Schulz, Gracelie A.S.; Fajardo, Andre R.

    2015-01-01

    Hydrogels, three-dimensional polymer networks that can absorb and retain impressive amounts of liquid, have shown a remarkable evolution in the past years. Since their first description, the hydrogels have replaced their inert characteristic by smart properties, which help enlarging the range of applicability of such soft materials in different fields. Hydrogels had been prepared from various polymers (including synthetic or natural or both), which allows obtaining materials with unique and desirable properties. This work deals with the preparation of hydrogels and hydrogel composites based on a synthetic/natural hybrid polymer network filled with bovine bone powder, which is composed mainly by hydroxyapatite (as inorganic phase) and collagen (as organic phase). The resulting materials were characterized by DRX, FTIR and TGA analyses. Additionally, water uptake capacity was estimated for both hydrogels and hydrogels composites samples by swelling assays. (author)

  17. Chitosan composite hydrogels reinforced with natural clay nanotubes.

    Science.gov (United States)

    Huang, Biao; Liu, Mingxian; Zhou, Changren

    2017-11-01

    Here, chitosan composites hydrogels were prepared by addition of halloysite nanotubes (HNTs) in the chitosan KOH/LiOH/urea solution. The raw chitosan and chitosan/HNTs composite hydrogels were obtained by heat treatment at 60°C for 8h and then regeneration in ethanol solution. The viscosity of the composite solution is increased with HNTs content. The Fourier transform infrared spectroscopy (FT-IR) shows that the hydrogen bonds interactions exist between the HNTs and the chitosan. X-ray diffraction (XRD) results show that the crystal structure of HNT is not changed in the composite hydrogels. The compressive property test and storage modulus determination show that the mechanical properties and anti-deformation ability of the composite hydrogel significantly increase owing to the reinforcing effect of HNTs. The composites hydrogel with 66.7% HNTs can undergo 7 times compression cycles without breaking with compressive strength of 0.71MPa at 70% deformation, while pure chitosan hydrogel is broken after bearing 5 compression cycles with compressive strength of 0.14MPa and a maximum deformation of 59%. A porous structure with pore size of 100-500μm is found in the composite hydrogels by scanning electron microscopy (SEM), and the pore size and the swelling ratio in NaCl solution decrease by the addition of HNTs and the immersing of ethanol. Chitosan/HNTs composite hydrogels show low cytotoxicity towards MC3T3-E1 cells. Also, the composite hydrogels show a maximum drug entrapment efficiency of 45.7% for doxorubicin (DOX) which is much higher than that of pure chitosan hydrogel (27.5%). All the results illustrate that the chitosan/HNTs composite hydrogels show promising applications as biomaterials. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Preparation and characterization of bioglass/polyvinyl alcohol composite hydrogel

    International Nuclear Information System (INIS)

    Xu Hong; Wang Yingjun; Zheng Yudong; Chen Xiaofeng; Ren Li; Wu Gang; Huang Xiaoshan

    2007-01-01

    In order to form firm active fixation with the adjacent bone, a new kind of bioactive composite hydrogel was prepared with polyvinyl alcohol (PVA) and bioglass (BG) through ultrasonic dispersion, heat-high-pressure and freeze/thawed technique. A digital speckle correlation method (DSCM) was utilized to characterize the mechanical properties of the series of BG/PVA composites. Results showed that at different load pressures, the composite hydrogel displayed different displacement and deformation in the V field. Results also showed that an increase of PVA percentage (15-30 wt%) or of bioglass percentage (2-10 wt%) in composite hydrogel could lead to an increase in the elastic compression modulus. Scanning electron microscope results indicated that bioglass was uniformly dispersed in the BG/PVA composite hydrogel. The BG/PVA composite hydrogel shows a promising prospect as a new bionic cartilage implantation material

  19. Evaluation of a novel thermosensitive heparin-poloxamer hydrogel for improving vascular anastomosis quality and safety in a rabbit model.

    Directory of Open Access Journals (Sweden)

    Ying-Zheng Zhao

    Full Text Available Despite progress in the design of advanced surgical techniques, stenosis recurs in a large percentage of vascular anastomosis. In this study, a novel heparin-poloxamer (HP hydrogel was designed and its effects for improving the quality and safety of vascular anastomosis were studied. HP copolymer was synthesized and its structure was confirmed by Fourier transform infrared spectroscopy (FTIR and nuclear magnetic resonance spectroscopy ((1H-NMR. Hydrogels containing HP were prepared and their important characteristics related to the application in vascular anastomosis including gelation temperature, rheological behaviour and micromorphology were measured. Vascular anastomosis were performed on the right common carotid arteries of rabbits, and the in vivo efficiency and safety of HP hydrogel to achieve vascular anastomosis was verified and compared with Poloxamer 407 hydrogel and the conventional hand-sewn method using Doppler ultrasound, CT angiograms, scanning electron microscopy (SEM and histological technique. Our results showed that HP copolymer displayed special gel-sol-gel phase transition behavior with increasing temperature from 5 to 60 °C. HP hydrogel prepared from 18 wt% HP solution had a porous sponge-like structure, with gelation temperature at approximately 38 °C and maximum elastic modulus at 10,000 Pa. In animal studies, imaging and histological examination of rabbit common jugular artery confirmed that HP hydrogel group had similar equivalent patency, flow and burst strength as Poloxamer 407 group. Moreover, HP hydrogel was superior to poloxamer 407 hydrogel and hand-sewn method for restoring the functions and epithelial structure of the broken vessel junctions after operation. By combining the advantages of heparin and poloxamer 407, HP hydrogel holds high promise for improving vascular anastomosis quality and safety.

  20. Osteoblastic differentiation of stem cells from human exfoliated deciduous teeth induced by thermosensitive hydrogels with strontium phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Su, Wen-Ta, E-mail: f10549@ntut.edu.tw [Department of Chemical Engineering and Biotechnology National Taipei University of Technology, Taipei, Taiwan (China); Chou, Wei-Ling [Department of Chemical Engineering and Biotechnology National Taipei University of Technology, Taipei, Taiwan (China); Chou, Chih-Ming [Department of Biochemistry, Taipei Medical University, Taipei, Taiwan (China)

    2015-07-01

    Stem cells from human exfoliated deciduous teeth (SHEDs) are a novel source of multi-potential stem cells for tissue engineering because of their potential to differentiate into multiple cell lineages. Strontium exhibits an important function in bone remodeling because it can simulate bone formation and decrease bone resorption. Hydrogels can mimic the natural cellular environment. The association of hydrogels with cell viability is determined using biological tests, including rheological experiments. In this study, osteogenic differentiation was investigated through SHED encapsulation in hydrogels containing strontium phosphate. Results of 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and proliferating cell nuclear antigen (PCNA) immunofluorescence staining indicated that the cells grew well and SHEDs proliferated in the hydrogels. Strontium-loaded chitosan-based hydrogels induced the biomineralization and high expression of alkaline phosphatase. Moreover, the expression levels of bone-related genes, including type-I collagen, Runx2, osteopontin (OP), and osteonectin (ON), were up-regulated during the osteogenic differentiation of SHEDs. This study demonstrated that strontium can be an effective inducer of osteogenesis for SHEDs. Elucidating the function of bioceramics (such as strontium) is useful in designing and developing strategies for bone tissue engineering. - Highlights: • SHEDs have been considered as alternative sources of adult stem cells in tissue engineering. • Strontium phosphate can enhance the osteogenic differentiation of SHEDs. • Hydrogels can mimic the natural cellular environment. • Bioceramics (such as strontium) is useful in designing and developing strategies for bone tissue engineering.

  1. Implementation of "Quality by Design (QbD)" Approach for the Development of 5-Fluorouracil Loaded Thermosensitive Hydrogel.

    Science.gov (United States)

    Dalwadi, Chintan; Patel, Gayatri

    2016-01-01

    The purpose of this study was to investigate Quality by Design (QbD) principle for the preparation of hydrogel products to prove both practicability and utility of executing QbD concept to hydrogel based controlled release systems. Product and process understanding will help in decreasing the variability of critical material and process parameters, which give quality product output and reduce the risk. This study includes the identification of the Quality Target Product Profiles (QTPPs) and Critical Quality Attributes (CQAs) from literature or preliminary studies. To identify and control the variability in process and material attributes, two tools of QbD was utilized, Quality Risk Management (QRM) and Experimental Design. Further, it helps to identify the effect of these attributes on CQAs. Potential risk factors were identified from fishbone diagram and screened by risk assessment and optimized by 3-level 2- factor experimental design with center points in triplicate, to analyze the precision of the target process. This optimized formulation was further characterized by gelling time, gelling temperature, rheological parameters, in-vitro biodegradation and in-vitro drug release. Design space was created using experimental design tool that gives the control space and working within this controlled space reduces all the failure modes below the risk level. In conclusion, QbD approach with QRM tool provides potent and effectual pyramid to enhance the quality into the hydrogel.

  2. A clinical trial designed to evaluate the safety and effectiveness of a thermosensitive hydrogel-type cultured epidermal allograft for deep second-degree burns.

    Science.gov (United States)

    Yim, Haejun; Yang, Hyeong-Tae; Cho, Yong-Suk; Kim, Dohern; Kim, Jong-Hyun; Chun, Wook; Hur, Jun

    2014-12-01

    This study is a phase 1 and 2 clinical trial for investigating the safety profile, effective treatment dose and effectiveness of the newly developed thermosensitive hydrogel-type cultured epidermal allograft. For phase 1, the keratinocytes were divided into 3 groups as follows, with 5 patients in each group: (1) low-dose group (6.7×10(6)/1.5mL), (2) medium-dose group (2×10(7)/1.5mL), and (3) high-dose group (6.0×10(7)/1.5mL). The second phase of the trial proceeded with 10 cases after choosing the most effective dose based on the analysis of the first phase. When comparing re-epithelialization time, medium- and high-dose group showed significantly shorter re-epithelialization time than low-dose group (p=0.003 and p=0.002). A total of 15 cases, 5 cases selected from phase 1 and 10 cases test in phase 2 with the medium dose, were compared with the re-epithelialization period. The re-epithelialization period was 9.6±4.0 days in the test site and 12.4±4.8 days in the control site. In the test site, re-epithelialization was 2.8±1.8 days faster than in the control site (pclinical trial. In conclusion, this new type of CEAllo accelerates wound healing time and shows the safety. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

  3. Intratumoral Delivery of Doxorubicin on Folate-Conjugated Graphene Oxide by In-Situ Forming Thermo-Sensitive Hydrogel for Breast Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Yi Teng Fong

    2017-11-01

    Full Text Available By taking advantage of the pH-sensitive drug release property of graphene oxide (GO after intracellular uptake, we prepared folic acid (FA-conjugated GO (GOFA for targeted delivery of the chemotherapeutic drug doxorubicin (DOX. GOFA-DOX was further encapsulated in an injectable in-situ forming thermo-sensitive hyaluronic acid-chitosan-g-poly(N-isopropylacrylamide (HACPN hydrogel for intratumoral delivery of DOX. As the degradation time of HACPN could be extended up to 3 weeks, intratumoral delivery of GOFA-DOX/HACPN could provide controlled and targeted delivery of DOX through slow degradation HACPN and subsequent cellular uptake of released GOFA-DOX by tumor cells through interactions of GOFA with folate receptors on the tumor cell’s surface. GOFA nano-carrier and HACPN hydrogel were first characterized for the physico-chemical properties. The drug loading experiments indicated the best preparation condition of GOFA-DOX was by reacting 0.1 mg GOFA with 2 mg DOX. GOFA-DOX showed pH-responsive drug release with ~5 times more DOX released at pH 5.5 than at pH 7.4 while only limited DOX was released from GOFA-DOX/HACPN at pH 7.4. Intracellular uptake of GOFA by endocytosis and release of DOX from GOFA-DOX in vitro could be confirmed from transmission electron microscopic and confocal laser scanning microscopic analysis with MCF-7 breast cancer cells. The targeting effect of FA was revealed when intracellular uptake of GOFA was blocked by excess FA. This resulted in enhanced in vitro cytotoxicity as revealed from the lower half maximal inhibitory concentration (IC50 value of GOFA-DOX (7.3 μg/mL compared with that of DOX (32.5 μg/mL and GO-DOX (10 μg/mL. The flow cytometry analysis indicated higher apoptosis rates for cells treated with GOFA-DOX (30% compared with DOX (8% and GO-DOX (11%. Animal studies were carried out with subcutaneously implanted MCF-7 cells in BALB/c nude mice and subject to intratumoral administration of drugs. The relative

  4. A composite hydrogels-based photonic crystal multi-sensor

    International Nuclear Information System (INIS)

    Chen, Cheng; Zhu, Zhigang; Zhu, Xiangrong; Yu, Wei; Liu, Mingju; Ge, Qiaoqiao; Shih, Wei-Heng

    2015-01-01

    A facile route to prepare stimuli-sensitive poly(vinyl alcohol)/poly(acrylic acid) (PVA/PAA) gelated crystalline colloidal array photonic crystal material was developed. PVA was physically gelated by utilizing an ethanol-assisted method, the resulting hydrogel/crystal composite film was then functionalized with PAA to form an interpenetrating hydrogel film. This sensor film is able to efficiently diffract the visible light and rapidly respond to various environmental stimuli such as solvent, pH and strain, and the accompanying structural color shift can be repeatedly changed and easily distinguished by naked eye. (paper)

  5. Hydrogel-Electrospun Fiber Mat Composite Coatings for Neural Prostheses

    Directory of Open Access Journals (Sweden)

    Ning eHan

    2011-03-01

    Full Text Available Achieving stable, long-term performance of implanted neural prosthetic devices has been challenging because of implantation related neuron loss and a foreign body response that results in encapsulating glial scar formation. To improve neuron-prosthesis integration and form chronic, stable interfaces, we investigated the potential of neurotrophin-eluting hydrogel-electrospun fiber mat (EFM composite coatings. In particular, poly(ethylene glycol-poly(ε-caprolactone (PEGPCL hydrogel- poly(ε-caprolactone (PCL EFM composites were applied as coatings for multielectrode arrays (MEAs. Coatings were stable and persisted on electrode surfaces for over 1 month under an agarose gel tissue phantom and over 9 months in a PBS immersion bath. To demonstrate drug release, a neurotrophin, nerve growth factor (NGF, was loaded in the PEGPCL hydrogel layer, and coating cytotoxicity and sustained NGF release were evaluated using a PC12 cell culture model. Quantitative MTT assays showed that these coatings had no significant toxicity toward PC12 cells, and neurite extension at day 7 and 14 confirmed sustained release of NGF at biologically significant concentrations for at least 2 weeks. Our results demonstrate that hydrogel-EFM composite materials can be applied to neural prostheses as a means to improve neuron-electrode proximity and enhance long-term device performance and function.

  6. Preparation and properties of GO-PVA composite hydrogel with oriented structure

    Science.gov (United States)

    Liu, Huanqing; Zhang, Gongzheng; Li, Huanjun

    2017-03-01

    We fabricated GO-PVA composite hydrogels with oriented structure by directional freezing and repeated freeze-thawing, which owned superior mechanical property and thermostability than PVA hydrogel. Due to physical interactions such as hydrogen bonding between surface of GO and PVA chains, GO-PVA composite hydrogel possessed higher crosslinking density and smaller pore size and can resist higher temperature and stronger force from outside than PVA hydrogel. These unique properties will endow GO-PVA hydrogel with greater potential application in biomedical materials.

  7. Effects of halloysite nanotubes on physical properties and cytocompatibility of alginate composite hydrogels

    International Nuclear Information System (INIS)

    Huang, Biao; Liu, Mingxian; Long, Zheru; Shen, Yan; Zhou, Changren

    2017-01-01

    Sodium alginate (SA)/halloysite nanotubes (HNTs) composite hydrogels were successfully prepared by solution blending and cross-linking with calcium ions. HNTs can improve the physical properties and cytocompatibility of composite hydrogels. The static and shear viscosity of SA/HNTs solution increase by the addition of HNTs. FTIR suggests the presence of hydrogen bond interactions between HNTs and SA. The crystal structure of HNTs is retained in the composites as showed by the X-ray diffraction result. A porous structure with pore size of 100–250 μm is found in the hydrogels, which can provide a space for cell growth and migration. The compressive mechanical properties of composite hydrogels significantly increase compared to the pure SA hydrogel. The SA/HNTs composite hydrogels with 80% HNTs loading exhibit the compressive stress at 80% strain of 2.99 MPa, while the stress at 80% strain of pure SA hydrogel is only 0.8 MPa. The dynamic storage modulus of composite hydrogels also markedly increases with HNTs concentration. The differential scanning calorimetry endothermic peak area and swelling ratios in NaCl solution of the composite hydrogels decrease by the addition of HNTs. Preosteoblast (MC3T3-E1) culture results reveal that the SA/HNTs composites especially at relatively low HNTs loading show a significant increase in cells adhesion and proliferation compared to the pure SA hydrogel. All the results demonstrate that the SA/HNTs composite hydrogels show a promising application in bone tissue engineering. - Highlights: • Alginate/HNTs composite hydrogels were fabricated using Ca 2+ cross-linking method. • The hydrogen bond interactions between HNTs and alginate are confirmed. • HNTs can significantly enhance the mechanical properties of alginate hydrogel. • HNTs can improve the cell attachment and proliferation of alginate.

  8. Effects of halloysite nanotubes on physical properties and cytocompatibility of alginate composite hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Biao; Liu, Mingxian, E-mail: liumx@jnu.edu.cn; Long, Zheru; Shen, Yan; Zhou, Changren, E-mail: tcrz9@jnu.edu.cn

    2017-01-01

    Sodium alginate (SA)/halloysite nanotubes (HNTs) composite hydrogels were successfully prepared by solution blending and cross-linking with calcium ions. HNTs can improve the physical properties and cytocompatibility of composite hydrogels. The static and shear viscosity of SA/HNTs solution increase by the addition of HNTs. FTIR suggests the presence of hydrogen bond interactions between HNTs and SA. The crystal structure of HNTs is retained in the composites as showed by the X-ray diffraction result. A porous structure with pore size of 100–250 μm is found in the hydrogels, which can provide a space for cell growth and migration. The compressive mechanical properties of composite hydrogels significantly increase compared to the pure SA hydrogel. The SA/HNTs composite hydrogels with 80% HNTs loading exhibit the compressive stress at 80% strain of 2.99 MPa, while the stress at 80% strain of pure SA hydrogel is only 0.8 MPa. The dynamic storage modulus of composite hydrogels also markedly increases with HNTs concentration. The differential scanning calorimetry endothermic peak area and swelling ratios in NaCl solution of the composite hydrogels decrease by the addition of HNTs. Preosteoblast (MC3T3-E1) culture results reveal that the SA/HNTs composites especially at relatively low HNTs loading show a significant increase in cells adhesion and proliferation compared to the pure SA hydrogel. All the results demonstrate that the SA/HNTs composite hydrogels show a promising application in bone tissue engineering. - Highlights: • Alginate/HNTs composite hydrogels were fabricated using Ca{sup 2+} cross-linking method. • The hydrogen bond interactions between HNTs and alginate are confirmed. • HNTs can significantly enhance the mechanical properties of alginate hydrogel. • HNTs can improve the cell attachment and proliferation of alginate.

  9. Characterization of alginate-brushite in-situ hydrogel composites

    Energy Technology Data Exchange (ETDEWEB)

    Dabiri, Seyed Mohammad Hossein [Department of Informatics, Bioengineering, Robotics, and System Engineering, University of Genoa, Genoa (Italy); Lagazzo, Alberto; Barberis, Fabrizio [Department of Civil, Chemical and Environmental Engineering, University of Genoa, Genoa (Italy); Farokhi, Mehdi [National Cell Bank of Iran, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of); Finochio, Elisabetta [Department of Civil, Chemical and Environmental Engineering, University of Genoa, Genoa (Italy); Pastorino, Laura [Department of Informatics, Bioengineering, Robotics, and System Engineering, University of Genoa, Genoa (Italy)

    2016-10-01

    In the present study alginate-brushite composite hydrogels were in-situ synthetized and characterized with respect to preparation parameters. Specifically, the influence of initial pH value and initial concentration of phosphate precursor on the in-situ fabrication of the composite hydrogel were taken into account. The composite hydrogels were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric (TGA, DTG) and differential thermal analysis (DTA). Finally, the cell viability tests were carried out (MTT) over the incubation time period of 3, 7, and 14 days. The results revealed that the formation and the crystalline stability of brushite were highly dependent on the initial pH value. It was shown that as the pH reached to the value of 6, characteristics peaks of brushite appeared in the FTIR spectra. Besides, the XRD and thermal analysis results were in a good accordance with those of FTIR. In addition, the SEM images demonstrated that the plate like brushite was formed inside the alginate matrix. Also, a considerable impact of pH variation on the biocompatibility of samples was noticed so that the majority of samples especially those prepared in the acidic conditions were toxic. - Highlights: • Alginate-brushite hydrogel composites were obtained through an in-situ process • The brushite crystals started forming at pH value of 6 • The increase in the initial concentration of phosphate precursor resulted in more crystalline structure • Samples prepared at pH value of 8 had the most stable crystalline structure • Brushite crystals promoted the biocompatibility of alginate.

  10. An Injectable Composite Gelatin Hydrogel with pH Response Properties

    Directory of Open Access Journals (Sweden)

    Baoguo Chen

    2017-01-01

    Full Text Available On account of minimally invasive procedure and of filling irregular defects of tissues, injectable hydrogels are increasingly attractive in biomedical fields. However, traditional hydrogel formed by simple physical interaction or in situ crosslinking had inevitably some drawbacks such as low mechanical strength and lack of multifunctional properties. Though many investigations had successfully modified traditional injectable hydrogel to obtain both mechanical and functional properties, an acetalated β-cyclodextrin (Ac-β-CD nanoparticle composite injectable hydrogel designed in the research was another effective and efficient choice to solve the drawbacks. First of all, gelatin derivative (G-AA and Ac-β-CD were synthesized to prepare hydrogel and nanoparticle, respectively. In order to ensure good compatibility between nanoparticle and macromonomer and provide crosslink points between nanoparticle and macromonomer, G-AA was simultaneously functionalized onto the surface of Ac-β-CD nanoparticle during the fabrication of Ac-β-CD nanoparticle using one-step method. Finally, injectable composite hydrogel was obtained by photoinitiated polymerization in situ. Hydrogel properties like gelation time and swelling ratio were investigated. The viscoelastic behavior of hydrogels confirmed that typical characteristics of crosslinked elastomer for all hydrogel and nanoparticle in hydrogel could improve the mechanical property of hydrogel. Moreover, the transparency with time had verified obvious acid-response properties of hydrogels.

  11. Cellularized cylindrical fiber/hydrogel composites for ligament tissue engineering.

    Science.gov (United States)

    Thayer, Patrick S; Dimling, Anna F; Plessl, Daniel S; Hahn, Mariah R; Guelcher, Scott A; Dahlgren, Linda A; Goldstein, Aaron S

    2014-01-13

    Electrospun meshes suffer from poor cell infiltration and limited thickness, which restrict their use to thin tissue applications. Herein, we demonstrate two complementary processes to overcome these limitations and achieve elastomeric composites that may be suitable for ligament repair. First, C3H10T1/2 mesenchymal stem cells were incorporated into electrospun meshes using a hybrid electrospinning/electrospraying process. Second, electrospun meshes were rolled and formed into composites with an interpenetrating polyethylene glycol (PEG) hydrogel network. Stiffer composites were formed from poly(lactic-co-glycolic acid) (PLGA) meshes, while softer and more elastic composites were formed from poly(ester-urethane urea) (PEUUR) meshes. As-spun PLGA and PEUUR rolled meshes had tensile moduli of 19.2 ± 1.9 and 0.86 ± 0.34 MPa, respectively, which changed to 11.6 ± 4.8 and 1.05 ± 0.39 MPa with the incorporation of a PEG hydrogel phase. In addition, cyclic tensile testing indicated that PEUUR-based composites deformed elastically to at least 10%. Finally, C3H10T1/2 cells incorporated into electrospun meshes survived the addition of the PEG phase and remained viable for up to 5 days. These results indicate that the fabricated cellularized composites are support cyclic mechanical conditioning, and have potential application in ligament repair.

  12. Synthesis and characterization of GO-hydrogels composites

    Science.gov (United States)

    Pereyra, J. Y.; Cuello, E. A.; Coneo Rodriguez, R.; Barbero, C. A.; Yslas, E. I.; Salavagione, H. J.; Acevedo, D. F.

    2017-10-01

    The preparation of poly(N-isopropylacrylamide) (PNIPAm) hydrogel nanocomposites containing graphene oxide (GO) and GO plus carbon nanotubes (CNT) in the polymer network is communicated. This one-pot preparation methods include the dispersion of GO (or GO plus CNT) in a solution of monomers and the subsequent polymerization. The texture of the nanocomposites was studied using scanning electron microscopy (SEM), where very compact surfaces are observed suggesting good dispersion of GO sheets and CNTs within the polymer matrix. The presence of GO inside the polymer network diminished the equilibrium swelling values and increased the elastic modulus up to 162 % with respect to the pure gel. Similar results were observed for the composite with CNT. Furthermore, the electrical resistivity of PNIPAm-GO diminishes as the applied compression force increases, being 50 % lower than hydrogel without GO. Moreover, the electrochemical properties of the hydrogels, evaluated by cyclic voltammetry, indicate highly reversible electrical charge/discharge response. In order to apply these materials for antibiotic delivery, the absorption of tetracycline (tet) is evaluated and the nanocomposites showed better absorption capability and improved antibiotic delivery. Preliminary results suggest that tet loaded PNIPAm-GO and PNIPAM-GO-CNT display antimicrobial activity against the Pseudomonas aeruginosa turning these materials as potential candidates for biomedical applications.

  13. Biomimetic Hydrogel Composites for Soil Stabilization and Contaminant Mitigation.

    Science.gov (United States)

    Zhao, Zhi; Hamdan, Nasser; Shen, Li; Nan, Hanqing; Almajed, Abdullah; Kavazanjian, Edward; He, Ximin

    2016-11-15

    We have developed a novel method to synthesize a hyper-branched biomimetic hydrogel network across a soil matrix to improve the mechanical strength of the loose soil and simultaneously mitigate potential contamination due to excessive ammonium. This method successfully yielded a hierarchical structure that possesses the water retention, ion absorption, and soil aggregation capabilities of plant root systems in a chemically controllable manner. Inspired by the robust organic-inorganic composites found in many living organisms, we have combined this hydrogel network with a calcite biomineralization process to stabilize soil. Our experiments demonstrate that poly(acrylic acid) (PAA) can work synergistically with enzyme-induced carbonate precipitation (EICP) to render a versatile, high-performance soil stabilization method. PAA-enhanced EICP provides multiple benefits including lengthening of water supply time, localization of cementation reactions, reduction of harmful byproduct ammonium, and achievement of ultrahigh soil strength. Soil crusts we have obtained can sustain up to 4.8 × 10 3 kPa pressure, a level comparable to cementitious materials. An ammonium removal rate of 96% has also been achieved. These results demonstrate the potential for hydrogel-assisted EICP to provide effective soil improvement and ammonium mitigation for wind erosion control and other applications.

  14. Biodegradable and thermosensitive monomethoxy poly(ethylene glycol)-poly(lactic acid) hydrogel as a barrier for prevention of post-operative abdominal adhesion.

    Science.gov (United States)

    Fu, Shao Zhi; Li, Zhi; Fan, Jun Ming; Meng, Xiao Hang; Shi, Kun; Qu, Ying; Yang, Ling Lin; Wu, Jing Bo; Fan, Juan; Luot, Feng; Qian, Zhi Yong

    2014-03-01

    Post-operative peritoneal adhesions are serious consequences of abdominal or pelvic surgery and cause severe bowel obstruction, chronic pelvic pain and infertility. In this study, a novel nano-hydrogel system based on a monomethoxy poly(ethylene glycol)-poly(lactic acid) (MPEG-PLA) di-block copolymer was studied for its ability to prevent abdominal adhesion in rats. The MPEG-PLA hydrogel at a concentration of 40% (w/v) was injected and was able to adhere to defect sites at body temperature. The ability of the hydrogel to inhibit adhesion of post-operative tissues was evaluated by utilizing a rat model of abdominal sidewall-cecum abrasion. It was possible to heal wounded tissue through regeneration of neo-peritoneal tissues ten days after surgery. Our data showed that this hydrogel system is equally as effective as current commercialized anti-adhesive products.

  15. Effects of halloysite nanotubes on physical properties and cytocompatibility of alginate composite hydrogels.

    Science.gov (United States)

    Huang, Biao; Liu, Mingxian; Long, Zheru; Shen, Yan; Zhou, Changren

    2017-01-01

    Sodium alginate (SA)/halloysite nanotubes (HNTs) composite hydrogels were successfully prepared by solution blending and cross-linking with calcium ions. HNTs can improve the physical properties and cytocompatibility of composite hydrogels. The static and shear viscosity of SA/HNTs solution increase by the addition of HNTs. FTIR suggests the presence of hydrogen bond interactions between HNTs and SA. The crystal structure of HNTs is retained in the composites as showed by the X-ray diffraction result. A porous structure with pore size of 100-250μm is found in the hydrogels, which can provide a space for cell growth and migration. The compressive mechanical properties of composite hydrogels significantly increase compared to the pure SA hydrogel. The SA/HNTs composite hydrogels with 80% HNTs loading exhibit the compressive stress at 80% strain of 2.99MPa, while the stress at 80% strain of pure SA hydrogel is only 0.8MPa. The dynamic storage modulus of composite hydrogels also markedly increases with HNTs concentration. The differential scanning calorimetry endothermic peak area and swelling ratios in NaCl solution of the composite hydrogels decrease by the addition of HNTs. Preosteoblast (MC3T3-E1) culture results reveal that the SA/HNTs composites especially at relatively low HNTs loading show a significant increase in cells adhesion and proliferation compared to the pure SA hydrogel. All the results demonstrate that the SA/HNTs composite hydrogels show a promising application in bone tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Composite hydrogels of bio-inspired protein polymers : mechanical and structural characterization

    NARCIS (Netherlands)

    Rombouts, W.H.

    2015-01-01

    In this thesis we presented various combinations of custom-designed protein polymers that formed composite hydrogels. In chapter 2, composite hydrogels were prepared by mixing silk-like block copolymers (CP2SE48CP2) with collagen-like block copolymers (T9CR4T9). We found that by

  17. Sequentially-crosslinked biomimetic bioactive glass/gelatin methacryloyl composites hydrogels for bone regeneration.

    Science.gov (United States)

    Zheng, Jiafu; Zhao, Fujian; Zhang, Wen; Mo, Yunfei; Zeng, Lei; Li, Xian; Chen, Xiaofeng

    2018-08-01

    In recent years, gelatin-based composites hydrogels have been intensively investigated because of their inherent bioactivity, biocompatibility and biodegradability. Herein, we fabricated photocrosslinkable biomimetic composites hydrogels from bioactive glass (BG) and gelatin methacryloyl (GelMA) by a sequential physical and chemical crosslinking (gelation + UV) approach. The results showed that the compressive modulus of composites hydrogels increased significantly through the sequential crosslinking approach. The addition of BG resulted in a significant increase in physiological stability and apatite-forming ability. In vitro data indicated that BG/GelMA composites hydrogels promoted cell attachment, proliferation and differentiation. Overall, the BG/GelMA composites hydrogels combined the advantages of good biocompatibility and bioactivity, and had potential applications in bone regeneration. Copyright © 2018. Published by Elsevier B.V.

  18. Preparation, optimization and property of PVA-HA/PAA composite hydrogel.

    Science.gov (United States)

    Chen, Kai; Liu, Jinlong; Yang, Xuehui; Zhang, Dekun

    2017-09-01

    PVA-HA/PAA composite hydrogel is prepared by freezing-thawing, PEG dehydration and annealing method. Orthogonal design method is used to choose the optimization combination. Results showed that HA and PVA have the maximum effect on water content. PVA and freezing-thawing cycles have the maximum effect on creep resistance and stress relaxation rate of hydrogel. Annealing temperature and freezing-thawing cycles have the maximum effect on compressive elastic modulus of hydrogel. Comparing with the water content and mechanical properties of 16 kinds of combination, PVA-HA/PAA composite hydrogel with freezing-thawing cycles of 3, annealing temperature of 120°C, PVA of 16%, HA of 2%, PAA of 4% has the optimization comprehensive properties. PVA-HA/PAA composite hydrogel has a porous network structure. There are some interactions between PVA, HA and PAA in hydrogel and the properties of hydrogel are strengthened. The annealing treatment improves the crystalline and crosslinking of hydrogel. Therefore, the annealing PVA-HA/PAA composite hydrogel has good thermostability, strength and mechanical properties. It also has good lubrication property and its friction coefficient is relative low. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. A study on synthesis and properties of Ag nanoparticles immobilized polyacrylamide hydrogel composites

    International Nuclear Information System (INIS)

    Saravanan, P.; Padmanabha Raju, M.; Alam, Sarfaraz

    2007-01-01

    Synthesis of Ag nanoparticles containing polyacrylamide (PAm) hydrogel composites was performed by free-radical cross-linking polymerization of acrylamide monomer in an aqueous medium containing Ag + ions. The Ag nanoparticle/PAm composites exhibit faint yellow colour and are found to stable under ambient conditions, without undergoing oxidation. TEM micrographs reveal the presence of nearly spherical and well-separated Ag nanoparticles with diameters in the range of 4-7 nm. UV-vis studies apparently show the characteristic surface plasmon band at ∼415 nm, for the existence of Ag nanoparticles within the hydrogel matrix. The effect of varying Ag + ion concentration within the PAm hydrogels on the amount of formation of Ag nanoparticles, as well as on the bulk properties of hydrogel nanocomposites such as equilibrium swelling, optical and electrical properties are studied. The Ag/PAm hydrogel nanocomposites have higher swelling ratio and lower electron transfer resistance than its corresponding conventional hydrogel

  20. A novel multi-responsive polyampholyte composite hydrogel with excellent mechanical strength and rapid shrinking rate.

    Science.gov (United States)

    Xu, Kun; Tan, Ying; Chen, Qiang; An, Huiyong; Li, Wenbo; Dong, Lisong; Wang, Pixin

    2010-05-15

    Series of hydrophilic core-shell microgels with cross-linked poly(N-isopropylacrylamide) (PNIPAAm) as core and poly(vinyl amine) (PVAm) as shell are synthesized via surfactant-free emulsion polymerization. Then, the microgels are treated with a small amount of potassium persulfate (KPS) to generate free radicals on the amine nitrogens of PVAm, which subsequently initiate the graft copolymerization of acrylic acid (AA), acryloyloxyethyl trimethyl ammonium chloride (DAC), and acrylamide (AAm) onto microgels to prepare multi-responsive composite hydrogels. The composite hydrogels consist of cross-linked ungrafted polyampholyte chains as the first network and microgels with grafted polyampholyte chains as graft point and second network and show surprising mechanical strength and rapid response rate. The investigation shows the compress strength of composite hydrogels is up to 17-30 MPa, which is 60-100 times higher than that of the hydrogel matrix. The composite hydrogel shows reversible switch of transmittance when traveling the lowest critical temperature (LCST) of microgels. When the composite hydrogel swollen in pH 2.86 solution at ambient condition is immersed into the pH 7.00 solution at 45 °C, a rapid dynamic shrinking can be observed. And the character time (τ) of shrinking dynamic of composite hydrogel is 251.9 min, which is less than that of hydrogel matrix (τ=2273.7 min). Copyright © 2010 Elsevier Inc. All rights reserved.

  1. Superabsorbent hydrogel composite based on copolymer cellulose/poly (vinyl alcohol)/CNT

    Energy Technology Data Exchange (ETDEWEB)

    Khoerunnisa, Fitri, E-mail: fitri.khoerunnisa@gmail.com; Hendrawan,; Sonjaya, Yaya; Putri, Oceu Dwi [Department of Chemistry, Indonesia University of Education, Setiabudi 229 Bandung, West Java, Indonesia 40154 (Indonesia)

    2016-04-19

    Superabsorbent hydrogels are cross-linked hydrophilic polymers that can absorb and retain a large volume of water, saline solution, or physiological fluids. A distinctive superabsorbent hydrogel composite based on cellulose/ poly (vinyl alcohol)/ carbon nanotubes was successfully synthesized via the graft bio-copolymerization in an aqueous medium with glutaraldehide as a crosslinking agent. The effect of carbon nanotubes (CNT) on water absorption capacity and mechanical properties of superabsorbent composite were particularly investigated. The Fourier transform infrared spectra showed the evidence of copolymerization of hydrogel precursors as well as the interaction of CNT filler with the hydrogel matrices, as indicated by the shifting of peak intensity and position of several functional groups (O-H, C-H sp{sup 3}, C=O, C-N, C-O). The modification of hydrogel surface morphology and porosity owing to CNT insertion was also confirmed by scanning electron microscopy images. The CNT insertion improved the mechanical strength of superabsorbent hydrogel composites. Moreover, insertion of CNT into hydrogel matrix remarkably increased the swelling capacity of superabsorbent composites up to 840%. This huge water absorption capacity of hydrogel composites offers promising applications in development of superabsorbent polymers.

  2. Superabsorbent hydrogel composite based on copolymer cellulose/poly (vinyl alcohol)/CNT

    International Nuclear Information System (INIS)

    Khoerunnisa, Fitri; Hendrawan,; Sonjaya, Yaya; Putri, Oceu Dwi

    2016-01-01

    Superabsorbent hydrogels are cross-linked hydrophilic polymers that can absorb and retain a large volume of water, saline solution, or physiological fluids. A distinctive superabsorbent hydrogel composite based on cellulose/ poly (vinyl alcohol)/ carbon nanotubes was successfully synthesized via the graft bio-copolymerization in an aqueous medium with glutaraldehide as a crosslinking agent. The effect of carbon nanotubes (CNT) on water absorption capacity and mechanical properties of superabsorbent composite were particularly investigated. The Fourier transform infrared spectra showed the evidence of copolymerization of hydrogel precursors as well as the interaction of CNT filler with the hydrogel matrices, as indicated by the shifting of peak intensity and position of several functional groups (O-H, C-H sp"3, C=O, C-N, C-O). The modification of hydrogel surface morphology and porosity owing to CNT insertion was also confirmed by scanning electron microscopy images. The CNT insertion improved the mechanical strength of superabsorbent hydrogel composites. Moreover, insertion of CNT into hydrogel matrix remarkably increased the swelling capacity of superabsorbent composites up to 840%. This huge water absorption capacity of hydrogel composites offers promising applications in development of superabsorbent polymers.

  3. Development of carboxymethyl cellulose-based hydrogel and nanosilver composite as antimicrobial agents for UTI pathogens.

    Science.gov (United States)

    Alshehri, Saad M; Aldalbahi, Ali; Al-Hajji, Abdullah Baker; Chaudhary, Anis Ahmad; Panhuis, Marc In Het; Alhokbany, Norah; Ahamad, Tansir

    2016-03-15

    Silver nanoparticles (AgNPs) containing hydrogel composite were first synthesized by preparing a new hydrogel from carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), and the cross-linker ethylene glycol diglycidyl ether (EGDE), followed by the incorporation of AgNPs by microwave radiation. The resulting neat hydrogels and AgNPs-hydrogel composites were characterized using spectral, thermal, microscopic analysis and X-ray diffraction (XRD) analyses. The SEM and TEM results demonstrated that the synthesized AgNPs were spherical with diameters ranging from 8 to 14nm. In addition, the XRD analysis confirmed the nanocrystalline phase of silver with face-centered cubic (FCC) crystal structure. Energy dispersive spectroscopy (EDS) analysis of the AgNPs confirmed the presence of an elemental silver signal, and no peaks of any other impurities were detected. Additionally, the antibacterial activities of the neat hydrogel and AgNPs-hydrogel composites were measured by Kirby-Bauer method against urinary tract infection (UTI) pathogens. The rheology measurement revealed that the values of storage modulus (G') were higher than that of loss modulus (G″). The AgNPs-hydrogel composites exhibited higher antibacterial activity against Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus vulgaris, Staphylococcus aureus and Proteus mirabilis compared to the corresponding neat hydrogel. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Super absorbent hydrogel composites as water retentive in soil

    International Nuclear Information System (INIS)

    Magalhaes, Antonio Savio G.; Almeida Neto, Manuel P.; Bezerra, Maslandia N.; Feitosa, Judith P.A.

    2011-01-01

    Super absorbent hydrogels (SAP) were synthesized at room temperature, by the use of potassium persulfate as initiator, N,N'-methylene bis acrylamide (MBA) as crosslinking agent, and N,N,N',N'- tetramethylethylenediamine. Gels at the same conditions were prepared with 10% of minerals (bentonite or dolomite). The materials of bentonite series were obtained from acrylamide followed by hydrolysis with NaOH. The gels of dolomite series were prepared from the two co-monomers (acrylamide and acrylate). All SAPs were characterized by elemental microanalysis, FTIR, x-ray diffraction, SEM, and by swelling measurements in water. An intercalated composite was obtained with bentonite hydrogel. After hydrolysis an exfoliated nanocomposite was formed. The dolomite mineral was dispersed in the polymeric matrix. The swelling degrees of the SAPs with mineral were higher than those gels without it. This degree was 1,000 times the dry gel weight. Taking into account the amount of water needed to the process, the gel with dolomite is the most promising as soil conditioner. (author)

  5. Development and evaluation of fast forming nano-composite hydrogel for ocular delivery of diclofenac.

    Science.gov (United States)

    Li, Xingyi; Zhang, Zhaoliang; Chen, Hao

    2013-05-01

    In this paper, a fast forming nano-composite hydrogel was developed for potential application in ocular drug delivery. The optical transmission (OT) as well as rheological properties of nano-composite hydrogel was characterized. The developed nano-composite hydrogel given a high diclofenac micelles loading and provided a sustained release manner of diclofenac within 6h. The developed nano-composite hydrogel formulation was administrated into the eye as flowable solution, quickly forming a hydrogel that is able to resist of the blinking and flushing of tear, yet resulting in the prolonged residence time of pre-corneal. In vivo eye irritation test suggested that the developed nano-composite hydrogel was none-eye irritation might be suitable for various ocular applications. In vivo pharmacokinetic study indicated that the developed nano-composite hydrogel could significantly increase the bioavailability of diclofenac and maintain the concentration of diclofenac in aqueous humor above MEC at least 24h after administration as compared with that of the commercial diclofenac sodium eye drops, which might be able to reduce the frequency of administration for patients. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Synthesis and characterization of chitosan-graft-poly(acrylic acid)/rice husk ash hydrogels composites

    International Nuclear Information System (INIS)

    Rodrigues, Francisco H.A.; Lopes, Gabriel V.; Pereira, Antonio G.B.; Fajardo, Andre R.; Muniz, Edvani C.

    2011-01-01

    According to environmental concerns, super absorbent hydrogel composites were synthesized based on rice husk ash (RHA), an industrial waste, and Chitosan-graft-poly(acrylic acid). The WAXS and FTIR data confirmed the syntheses of hydrogel composites. The effect of crystalline or amorphous RHA on water uptake was investigated. It was found that the RHA in crystalline form induces higher water capacity (W eq ) of composites hydrogels due to the fact that the intra-interactions among silanol groups on RHA make available new sites in the polymer matrix, which could interact to water. (author)

  7. Creating Stiff, Tough, and Functional Hydrogel Composites with Low-Melting-Point Alloys.

    Science.gov (United States)

    Takahashi, Riku; Sun, Tao Lin; Saruwatari, Yoshiyuki; Kurokawa, Takayuki; King, Daniel R; Gong, Jian Ping

    2018-04-01

    Reinforcing hydrogels with a rigid scaffold is a promising method to greatly expand the mechanical and physical properties of hydrogels. One of the challenges of creating hydrogel composites is the significant stress that occurs due to swelling mismatch between the water-swollen hydrogel matrix and the rigid skeleton in aqueous media. This stress can cause physical deformation (wrinkling, buckling, or fracture), preventing the fabrication of robust composites. Here, a simple yet versatile method is introduced to create "macroscale" hydrogel composites, by utilizing a rigid reinforcing phase that can relieve stress-induced deformation. A low-melting-point alloy that can transform from a load-bearing solid state to a free-deformable liquid state at relatively low temperature is used as a reinforcing skeleton, which enables the release of any swelling mismatch, regardless of the matrix swelling degree in liquid media. This design can generally provide hydrogels with hybridized functions, including excellent mechanical properties, shape memory, and thermal healing, which are often difficult or impossible to achieve with single-component hydrogel systems. Furthermore, this technique enables controlled electrochemical reactions and channel-structure templating in hydrogel matrices. This work may play an important role in the future design of soft robots, wearable electronics, and biocompatible functional materials. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Poloxamer 407/188 binary thermosensitive hydrogels as delivery systems for infiltrative local anesthesia: Physico-chemical characterization and pharmacological evaluation

    International Nuclear Information System (INIS)

    Akkari, Alessandra C.S.; Papini, Juliana Z. Boava; Garcia, Gabriella K.; Franco, Margareth K.K. Dias; Cavalcanti, Leide P.; Gasperini, Antonio; Alkschbirs, Melissa Inger; Yokaichyia, Fabiano; Paula, Eneida de; Tófoli, Giovana R.; Araujo, Daniele R. de

    2016-01-01

    In this study, we reported the development and the physico-chemical characterization of poloxamer 407 (PL407) and poloxamer 188 (PL188) binary systems as hydrogels for delivering ropivacaine (RVC), as drug model, and investigate their use in infiltrative local anesthesia for applications on the treatment of post-operative pain. We studied drug-micelle interaction and micellization process by light scattering and differential scanning calorimetry (DSC), the sol-gel transition and hydrogel supramolecular structure by small-angle-X-ray scattering (SAXS) and morphological evaluation by Scanning Electron Microscopy (SEM). In addition, we have presented the investigation of drug release mechanisms, in vitro/in vivo toxic and analgesic effects. Micellar dimensions evaluation showed the formation of PL407-PL188 mixed micelles and the drug incorporation, as well as the DSC studies showed increased enthalpy values for micelles formation after addition of PL 188 and RVC, indicating changes on self-assembly and the mixed micelles formation evoked by drug incorporation. SAXS studies revealed that the phase organization in hexagonal structure was not affected by RVC insertion into the hydrogels, maintaining their supramolecular structure. SEM analysis showed similar patterns after RVC addition. The RVC release followed the Higuchi model, modulated by the PL final concentration and the insertion of PL 188 into the system. Furthermore, the association PL407-PL188 induced lower in vitro cytotoxic effects, increased the duration of analgesia, in a single-dose model study, without evoking in vivo inflammation signs after local injection. - Highlights: • We present the development and relationships between physico-chemical and biopharmaceutical/pharmacological parameters for the PL407-PL188 binary hydrogel, as well as its use for infiltrative local anesthesia • The addition of PL188 and RVC evoked changes on enthalpy values, self-assembly and the mixed micelles formation • The

  9. Poloxamer 407/188 binary thermosensitive hydrogels as delivery systems for infiltrative local anesthesia: Physico-chemical characterization and pharmacological evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Akkari, Alessandra C.S. [Human and Natural Sciences Center, ABC Federal University, Santo André, SP (Brazil); Papini, Juliana Z. Boava [São Francisco University, Bragança Paulista, São Paulo (Brazil); Garcia, Gabriella K. [Human and Natural Sciences Center, ABC Federal University, Santo André, SP (Brazil); Franco, Margareth K.K. Dias [Nuclear and Energy Research Institute, São Paulo, SP (Brazil); Cavalcanti, Leide P. [School of Chemical Engineering, University of Campinas, SP (Brazil); Gasperini, Antonio; Alkschbirs, Melissa Inger [Brazilian Synchrotron Light Laboratory, Campinas, SP (Brazil); Yokaichyia, Fabiano [Department Quantum Phenomena in Novel Materials Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin (Germany); Paula, Eneida de [Department of Biochemistry, Institute of Biology, State University of Campinas, Campinas, SP (Brazil); Tófoli, Giovana R. [Faculty of Dentistry São Leopoldo Mandic, Campinas, São Paulo (Brazil); Araujo, Daniele R. de, E-mail: daniele.araujo@ufabc.edu.br [Human and Natural Sciences Center, ABC Federal University, Santo André, SP (Brazil)

    2016-11-01

    In this study, we reported the development and the physico-chemical characterization of poloxamer 407 (PL407) and poloxamer 188 (PL188) binary systems as hydrogels for delivering ropivacaine (RVC), as drug model, and investigate their use in infiltrative local anesthesia for applications on the treatment of post-operative pain. We studied drug-micelle interaction and micellization process by light scattering and differential scanning calorimetry (DSC), the sol-gel transition and hydrogel supramolecular structure by small-angle-X-ray scattering (SAXS) and morphological evaluation by Scanning Electron Microscopy (SEM). In addition, we have presented the investigation of drug release mechanisms, in vitro/in vivo toxic and analgesic effects. Micellar dimensions evaluation showed the formation of PL407-PL188 mixed micelles and the drug incorporation, as well as the DSC studies showed increased enthalpy values for micelles formation after addition of PL 188 and RVC, indicating changes on self-assembly and the mixed micelles formation evoked by drug incorporation. SAXS studies revealed that the phase organization in hexagonal structure was not affected by RVC insertion into the hydrogels, maintaining their supramolecular structure. SEM analysis showed similar patterns after RVC addition. The RVC release followed the Higuchi model, modulated by the PL final concentration and the insertion of PL 188 into the system. Furthermore, the association PL407-PL188 induced lower in vitro cytotoxic effects, increased the duration of analgesia, in a single-dose model study, without evoking in vivo inflammation signs after local injection. - Highlights: • We present the development and relationships between physico-chemical and biopharmaceutical/pharmacological parameters for the PL407-PL188 binary hydrogel, as well as its use for infiltrative local anesthesia • The addition of PL188 and RVC evoked changes on enthalpy values, self-assembly and the mixed micelles formation • The

  10. Tunable hydrogel composite with two-step processing in combination with innovative hardware upgrade for cell-based three-dimensional bioprinting.

    Science.gov (United States)

    Wüst, Silke; Godla, Marie E; Müller, Ralph; Hofmann, Sandra

    2014-02-01

    Three-dimensional (3-D) bioprinting is the layer-by-layer deposition of biological material with the aim of achieving stable 3-D constructs for application in tissue engineering. It is a powerful tool for the spatially directed placement of multiple materials and/or cells within the 3-D sample. Encapsulated cells are protected by the bioink during the printing process. Very few materials are available that fulfill requirements for bioprinting as well as provide adequate properties for cell encapsulation during and after the printing process. A hydrogel composite including alginate and gelatin precursors was tuned with different concentrations of hydroxyapatite (HA) and characterized in terms of rheology, swelling behavior and mechanical properties to assess the versatility of the system. Instantaneous as well as long-term structural integrity of the printed hydrogel was achieved with a two-step mechanism combining the thermosensitive properties of gelatin with chemical crosslinking of alginate. Novel syringe tip heaters were developed for improved temperature control of the bioink to avoid clogging. Human mesenchymal stem cells mixed into the hydrogel precursor survived the printing process and showed high cell viability of 85% living cells after 3 days of subsequent in vitro culture. HA enabled the visualization of the printed structures with micro-computed tomography. The inclusion of HA also favors the use of the bioink for bone tissue engineering applications. By adding factors other than HA, the composite could be used as a bioink for applications in drug delivery, microsphere deposition or soft tissue engineering. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  11. Magnetic nanohydroxyapatite/PVA composite hydrogels for promoted osteoblast adhesion and proliferation.

    Science.gov (United States)

    Hou, Ruixia; Zhang, Guohua; Du, Gaolai; Zhan, Danxia; Cong, Yang; Cheng, Yajun; Fu, Jun

    2013-03-01

    This paper reports on the systematic investigation of novel magnetic nano-hydroxyapatite/PVA composite hydrogels through cyclic freeze-thawing with controllable structure, mechanical properties, and cell adhesion and proliferation properties. The content of the magnetic nano-hydroxyapatite-coated γ-Fe(2)O(3) (m-nHAP) particles exhibited remarkable influence on the porous structures and compressive strength of the nanocomposite hydrogels. The average pore diameter of the nanocomposite hydrogels exhibited a minimum of 1.6 ± 0.3 μm whereas the compressive strength reached a maximum of about 29.6 ± 6.5 MPa with the m-nHAP content of around 10 wt% in the nanocomposite hydrogels. In order to elucidate the influence of the composite m-nHAP on the cell adhesion and proliferation on the composite hydrogels, the PVA, γ-Fe(2)O(3)/PVA, nHAP/PVA and m-nHAP/PVA hydrogels were seeded and cultured with osteoblasts. The results demonstrated that the osteoblasts preferentially adhered to and proliferated on the m-nHAP/PVA hydrogels, in comparison to the PVA and nHAP/PVA hydrogels, whereas the γ-Fe(2)O(3)/PVA hydrogels appeared most favorable to the osteoblasts. Moreover, with the increasing m-nHAP content in the composite hydrogels, the adhesion density and proliferation of the osteoblasts were significantly promoted, especially at the content of around 50 wt%. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Poloxamer 407/188 binary thermosensitive hydrogels as delivery systems for infiltrative local anesthesia: Physico-chemical characterization and pharmacological evaluation.

    Science.gov (United States)

    Akkari, Alessandra C S; Papini, Juliana Z Boava; Garcia, Gabriella K; Franco, Margareth K K Dias; Cavalcanti, Leide P; Gasperini, Antonio; Alkschbirs, Melissa Inger; Yokaichyia, Fabiano; de Paula, Eneida; Tófoli, Giovana R; de Araujo, Daniele R

    2016-11-01

    In this study, we reported the development and the physico-chemical characterization of poloxamer 407 (PL407) and poloxamer 188 (PL188) binary systems as hydrogels for delivering ropivacaine (RVC), as drug model, and investigate their use in infiltrative local anesthesia for applications on the treatment of post-operative pain. We studied drug-micelle interaction and micellization process by light scattering and differential scanning calorimetry (DSC), the sol-gel transition and hydrogel supramolecular structure by small-angle-X-ray scattering (SAXS) and morphological evaluation by Scanning Electron Microscopy (SEM). In addition, we have presented the investigation of drug release mechanisms, in vitro/in vivo toxic and analgesic effects. Micellar dimensions evaluation showed the formation of PL407-PL188 mixed micelles and the drug incorporation, as well as the DSC studies showed increased enthalpy values for micelles formation after addition of PL 188 and RVC, indicating changes on self-assembly and the mixed micelles formation evoked by drug incorporation. SAXS studies revealed that the phase organization in hexagonal structure was not affected by RVC insertion into the hydrogels, maintaining their supramolecular structure. SEM analysis showed similar patterns after RVC addition. The RVC release followed the Higuchi model, modulated by the PL final concentration and the insertion of PL 188 into the system. Furthermore, the association PL407-PL188 induced lower in vitro cytotoxic effects, increased the duration of analgesia, in a single-dose model study, without evoking in vivo inflammation signs after local injection. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Autonomic composite hydrogels by reactive printing: materials and oscillatory response.

    Science.gov (United States)

    Kramb, R C; Buskohl, P R; Slone, C; Smith, M L; Vaia, R A

    2014-03-07

    Autonomic materials are those that automatically respond to a change in environmental conditions, such as temperature or chemical composition. While such materials hold incredible potential for a wide range of uses, their implementation is limited by the small number of fully-developed material systems. To broaden the number of available systems, we have developed a post-functionalization technique where a reactive Ru catalyst ink is printed onto a non-responsive polymer substrate. Using a succinimide-amine coupling reaction, patterns are printed onto co-polymer or biomacromolecular films containing primary amine functionality, such as polyacrylamide (PAAm) or poly-N-isopropyl acrylamide (PNIPAAm) copolymerized with poly-N-(3-Aminopropyl)methacrylamide (PAPMAAm). When the films are placed in the Belousov-Zhabotinsky (BZ) solution medium, the reaction takes place only inside the printed nodes. In comparison to alternative BZ systems, where Ru-containing monomers are copolymerized with base monomers, reactive printing provides facile tuning of a range of hydrogel compositions, as well as enabling the formation of mechanically robust composite monoliths. The autonomic response of the printed nodes is similar for all matrices in the BZ solution concentrations examined, where the period of oscillation decreases in response to increasing sodium bromate or nitric acid concentration. A temperature increase reduces the period of oscillations and temperature gradients are shown to function as pace-makers, dictating the direction of the autonomic response (chemical waves).

  14. Hydrogel/bioactive glass composites for bone regeneration applications: Synthesis and characterisation

    International Nuclear Information System (INIS)

    Killion, John A.; Kehoe, Sharon; Geever, Luke M.; Devine, Declan M.; Sheehan, Eoin; Boyd, Daniel; Higginbotham, Clement L.

    2013-01-01

    Due to the deficiencies of current commercially available biological bone grafts, alternative bone graft substitutes have come to the forefront of tissue engineering in recent times. The main challenge for scientists in manufacturing bone graft substitutes is to obtain a scaffold that has sufficient mechanical strength and bioactive properties to promote formation of new tissue. The ability to synthesise hydrogel based composite scaffolds using photopolymerisation has been demonstrated in this study. The prepared hydrogel based composites were characterised using techniques including Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy-dispersive X-ray spectrometry (EDX), rheological studies and compression testing. In addition, gel fraction, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), porosity and swelling studies of the composites were carried out. It was found that these novel hydrogel bioglass composite formulations did not display the inherent brittleness that is typically associated with bioactive glass based bone graft materials and exhibited enhanced biomechanical properties compared to the polyethylene glycol hydrogel scaffolds along. Together, the combination of enhanced mechanical properties and the deposition of apatite on the surface of these hydrogel based composites make them an ideal candidate as bone graft substitutes in cancellous bone defects or low load bearing applications. Highlights: • Young's modulus increases with the addition of bioactive glasses. • Hydrogel based composites formed an apatite layer in simulated body fluid. • Storage modulus increases with addition of bioactive glasses. • Compressive strength is dependent on molecular weight and bioactive glass loading

  15. Fabrication and mechanical characterization of graphene oxide-reinforced poly (acrylic acid)/gelatin composite hydrogels

    Science.gov (United States)

    Faghihi, Shahab; Gheysour, Mahsa; Karimi, Alireza; Salarian, Reza

    2014-02-01

    Hydrogels have found many practical uses in drug release, wound dressing, and tissue engineering. However, their applications are restricted due to their weak mechanical properties. The role of graphene oxide nanosheets (GONS) as reinforcement agent in poly (acrylic acid) (PAA)/Gelatin (Gel) composite hydrogels is investigated. Composite hydrogels are synthesized by thermal initiated redox polymerization method. Samples are then prepared with 20 and 40 wt. % of PAA, an increasing amount of GONS (0.1, 0.2, and 0.3 wt. %), and a constant amount of Gel. Subsequently, cylindrical hydrogel samples are subjected to a series of compression tests in order to measure their elastic modulus, maximum stress and strain. The results exhibit that the addition of GONS increases the Young's modulus and maximum stress of hydrogels significantly as compared with control (0.0 wt. % GONS). The highest Young's modulus is observed for hydrogel with GO (0.2 wt. %)/PAA (20 wt. %), whereas the highest maximum stress is detected for GO (0.2 wt. %)/PAA (40 wt. %) specimen. The addition of higher amounts of GONS leads to a decrease in the maximum stress of the hydrogel GO (0.3 wt. %)/PAA (40 wt. %). No significant differences are detected for the maximum strain among the hydrogel samples, as the amount of GONS increased. These results suggest that the application of GONS could be used to improve mechanical properties of hydrogel materials. This study may provide an alternative for the fabrication of low-cost graphene/polymer composites with enhanced mechanical properties beneficial for tissue engineering applications.

  16. Hydrogel core flexible matrix composite (H-FMC) actuators: theory and preliminary modelling

    International Nuclear Information System (INIS)

    Dicker, M P M; Weaver, P M; Bond, I P; Rossiter, J M

    2014-01-01

    The underlying theory of a new actuator concept based on hydrogel core flexible matrix composites (H-FMC) is presented. The key principle that underlines the H-FMC actuator operation is that the three-dimensional swelling of a hydrogel is partially constrained in order to improve the amount of useful work done. The partial constraint is applied to the hydrogel by a flexible matrix composite (FMC) that minimizes the hydrogel's volume expansion while swelling. This constraint serves to maximize the fixed charge density and resulting osmotic pressure, the driving force behind actuation. In addition, for certain FMC fibre orientations the Poisson's ratio of the anisotropic FMC laminate converts previously unused hydrogel swelling in the radial and circumferential directions into useful axial strains. The potential benefit of the H-FMC concept to hydrogel actuator performance is shown through comparison of force–stroke curves and evaluation of improvements in useful actuation work. The model used to achieve this couples chemical and electrical components, represented with the Nernst–Plank and Poisson equations, as well as a linear elastic mechanical material model, encompassing limited geometric nonlinearities. It is found that improvements in useful actuation work in the order of 1500% over bare hydrogel performance are achieved by the H-FMC concept. A parametric study is also undertaken to determine the effect of various FMC design parameters on actuator free strain and blocking stress. A comparison to other actuator concepts is also included. (paper)

  17. Development of hydrogels composites for potential use as biomaterials; Desenvolvimento de hidrogeis compositos para potencial uso como biomateriais

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Gabriela T. da; Alves, Natali O.; Schulz, Gracelie A.S.; Fajardo, Andre R., E-mail: gabizinhaaa.teixeira@hotmail.com [Universidade Federal de Pelotas (LaCoPol/UFPel), Pelotas, RS (Brazil). Centro de Ciencias Quimicas, Farmaceuticas e de Alimentos. Lab. de Tecnologia e Desenvolvimento de Compositos e Materiais Polimericos

    2015-07-01

    Hydrogels, three-dimensional polymer networks that can absorb and retain impressive amounts of liquid, have shown a remarkable evolution in the past years. Since their first description, the hydrogels have replaced their inert characteristic by smart properties, which help enlarging the range of applicability of such soft materials in different fields. Hydrogels had been prepared from various polymers (including synthetic or natural or both), which allows obtaining materials with unique and desirable properties. This work deals with the preparation of hydrogels and hydrogel composites based on a synthetic/natural hybrid polymer network filled with bovine bone powder, which is composed mainly by hydroxyapatite (as inorganic phase) and collagen (as organic phase). The resulting materials were characterized by DRX, FTIR and TGA analyses. Additionally, water uptake capacity was estimated for both hydrogels and hydrogels composites samples by swelling assays. (author)

  18. Viscoelastic behaviour of hydrogel-based composites for tissue engineering under mechanical load.

    Science.gov (United States)

    Kocen, Rok; Gasik, Michael; Gantar, Ana; Novak, Saša

    2017-03-06

    Along with biocompatibility, bioinductivity and appropriate biodegradation, mechanical properties are also of crucial importance for tissue engineering scaffolds. Hydrogels, such as gellan gum (GG), are usually soft materials, which may benefit from the incorporation of inorganic particles, e.g. bioactive glass, not only due to the acquired bioactivity, but also due to improved mechanical properties. They exhibit complex viscoelastic properties, which can be evaluated in various ways. In this work, to reliably evaluate the effect of the bioactive glass (BAG) addition on viscoelastic properties of the composite hydrogel, we employed and compared the three most commonly used techniques, analyzing their advantages and limitations: monotonic uniaxial unconfined compression, small amplitude oscillatory shear (SAOS) rheology and dynamic mechanical analysis (DMA). Creep and small amplitude dynamic strain-controlled tests in DMA are suggested as the best ways for the characterization of mechanical properties of hydrogel composites, whereas the SAOS rheology is more useful for studying the hydrogel's processing kinetics, as it does not induce volumetric changes even at very high strains. Overall, the results confirmed a beneficial effect of BAG (nano)particles on the elastic modulus of the GG-BAG composite hydrogel. The Young's modulus of 6.6 ± 0.8 kPa for the GG hydrogel increased by two orders of magnitude after the addition of 2 wt.% BAG particles (500-800 kPa).

  19. Applications of chitosan-based thermo-sensitive copolymers for harvesting living cell sheet

    International Nuclear Information System (INIS)

    Chen, J.-P.; Yang, T.-F.

    2008-01-01

    A thermo-sensitive chitosan-based copolymer hydrogel was used for harvesting living cell sheets. The hydrogel was tested for harvesting 3T3 cells after carrying out cell culture at 37 deg. C and incubating the confluent cells at 20 deg. C for spontaneous detachment of cell sheets from hydrogel surface without enzyme treatment. Results from cell viability assay and microscopy observations demonstrated that cells could attach to the hydrogel surface and maintain high viability and proliferation ability. Cell detachment efficiency from the hydrogel was about 80%. The detached cell sheet retained high viability and could proliferate again after transferred to a new culture surface

  20. Dual growth factor delivery from bilayered, biodegradable hydrogel composites for spatially-guided osteochondral tissue repair

    NARCIS (Netherlands)

    Lu, S.; Lam, J.; Trachtenberg, J.E.; Lee, E.J.; Seyednejad, H.; van den Beucken, J.J.; Tabata, Y.; Wong, M.E.; Jansen, J.A.; Mikos, A.G.; Kasper, F.K.

    2014-01-01

    The present work investigated the use of biodegradable hydrogel composite scaffolds, based on the macromer oligo(poly(ethylene glycol) fumarate) (OPF), to deliver growth factors for the repair of osteochondral tissue in a rabbit model. In particular, bilayered OPF composites were used to mimic the

  1. Preparation and characterization of a novel sodium alginate incorporated self-assembled Fmoc-FF composite hydrogel

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Xiao [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620 (China); Branford-White, Christopher [Institute for Health Research and Policy, London Metropolitan University, London N78 DB (United Kingdom); Tao, Lei [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); Li, Shubai [Changzhou Institute of Engineering Technology, Changzhou 213164 (China); Quan, Jing [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); Nie, Huali, E-mail: niehuali@dhu.edu.cn [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620 (China); Zhu, Limin, E-mail: lzhu@dhu.edu.cn [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China)

    2016-01-01

    Dipeptides and their derivatives have attracted tremendous attention owning to their excellent abilities of self-assemble assembling into various structures which have great potentials for applications in biology and/or nanotechnology. In the present study, we dedicate to fabricate a rigid and structure controllable Fmoc-FF/SA composite hydrogel. We found that the modified dipeptide, fluorenyl-9-methoxycarbonyl (Fmoc)-diphenylalanine (Phe-Phe) can self-assemble into rigid hydrogels with structures of nanowires, layered thin films or honeycombs as the change of sodium alginate (SA) concentration. Meanwhile, CD-spectroscopy demonstrated that SA appeared to control the process, but it did not change the arrangement of the Fmoc-FF peptide. Our results demonstrated that the formed hydrogel showed physical and chemical stability as well as possessing good biocompatibility. Rheological measurements showed that the addition of SA could improve the stability of the hydrogel. Cell viability assay revealed that the Fmoc-FF and Fmoc-FF/SA hydrogels are both beneficial for cell proliferation in-vitro. Our results indicated that the fabricated Fmoc-FF/SA composite hydrogels could be used in tissue engineering and drug delivery in the future. - Highlights: • A facile, time-saving approach to assemble Fomc-FF composite hydrogels was designed. • Hydrogel structures including nanowires, layered films and honeycombs can be controlled. • The role of SA in the Fmoc-FF/SA composite hydrogel was further clarified.

  2. Cadmium sulfide quantum dots/poly(acrylic acid-co-acrylic amide) composite hydrogel synthesized by gamma irradiation

    Science.gov (United States)

    Yang, Tao; Li, Qing; Wen, Wanxin; Hu, Liang; He, Weiwei; Liu, Hanzhou

    2018-04-01

    To improve the durability and stability of quantum dots (QDs) in the composite hydrogel, an irradiation induced reduction and polymerization-crosslinking method was reported herein where CdS QDs could be synthesized in situ and fastened to polymer chains due to the coordination forces between amino groups and CdS nanoparticles. The morphology and photoluminescence (PL) property of the composite hydrogel were studied. The result indicated that the CdS QDs with uniform size were dispersed evenly in the composite hydrogel, and the introduced CdS QDs had no obvious effect on the hydrogel structure. With the increases of reagent concentrations, PL intensity of the composite hydrogel was enhanced; however, the emission wavelength had no change.

  3. TECHNOLOGY OF FRESH HERBS STORAGE USING HYDROGEL AND ANTIOXIDANT COMPOSITION

    Directory of Open Access Journals (Sweden)

    Olesia PRISS

    2017-12-01

    Full Text Available There is a stable consumer demand for fresh culinary herbs. Also, the greenery contains a large number of valuable phytonutrients. Despite high efficiency and increasing annual production of fresh herbs, the problem of preserving their quality in the post-harvest period remains unresolved. Because of the high specific surface area of evaporation, in the green crops droop quickly, they lose their marketable quality, and, as a result, the level of profitability of greenery production in general is being reduced. It is necessary to use new effective approaches to leafy greens storage in order to reduce product losses during transportation and storage. For example, agrarian hydrogel can be used for storage of greenery. Hydrogel is an acrylic potassium polymer that is non-toxic and has a high environmental standard. The hydrogel granules can absorb up to 250 times more moisture than their weight. We propose the following procedure as the method of greenery preservation: the greens are packed in bundles and put in sticks in polyethylene bags with a fastener, pre-filled with hydrogel solutions. The storage temperature is maintained optimally for each species of fresh herbs, the relative humidity is 95 ± 3%. Usage of the proposed method allows obtaining environment-friendly products, preserving their high biological value and increasing the shelf life. The accumulation of peroxide products, which cause physiological disorders, is inhibited as the result of such storage. The use of hydrogel reduces the natural loss of mass by 10% as compared with the control. Duration of greenery storage increases by 30 days.

  4. Self-Supporting Nanoclay as Internal Scaffold Material for Direct Printing of Soft Hydrogel Composite Structures in Air.

    Science.gov (United States)

    Jin, Yifei; Liu, Chengcheng; Chai, Wenxuan; Compaan, Ashley; Huang, Yong

    2017-05-24

    Three dimensional (3D) bioprinting technology enables the freeform fabrication of complex constructs from various hydrogels and is receiving increasing attention in tissue engineering. The objective of this study is to develop a novel self-supporting direct hydrogel printing approach to extrude complex 3D hydrogel composite structures in air without the help of a support bath. Laponite, a member of the smectite mineral family, is investigated to serve as an internal scaffold material for the direct printing of hydrogel composite structures in air. In the proposed printing approach, due to its yield-stress property, Laponite nanoclay can be easily extruded through a nozzle as a liquid and self-supported after extrusion as a solid. Its unique crystal structure with positive and negative charges enables it to be mixed with many chemically and physically cross-linked hydrogels, which makes it an ideal internal scaffold material for the fabrication of various hydrogel structures. By mixing Laponite nanoclay with various hydrogel precursors, the hydrogel composites retain their self-supporting capacity and can be printed into 3D structures directly in air and retain their shapes before cross-linking. Then, the whole structures are solidified in situ by applying suitable cross-linking stimuli. The addition of Laponite nanoclay can effectively improve the mechanical and biological properties of hydrogel composites. Specifically, the addition of Laponite nanoclay results in a significant increase in the Young's modulus of each hydrogel-Laponite composite: 1.9-fold increase for the poly(ethylene glycol) diacrylate (PEGDA)-Laponite composite, 7.4-fold increase for the alginate-Laponite composite, and 3.3-fold increase for the gelatin-Laponite composite.

  5. Optical sensing properties of Au nanoparticle/hydrogel composite microbeads using droplet microfluidics

    Science.gov (United States)

    Li, Huilin; Men, Dandan; Sun, Yiqiang; Zhang, Tao; Hang, Lifeng; Liu, Dilong; Li, Cuncheng; Cai, Weiping; Li, Yue

    2017-10-01

    Uniform Au nanoparticle (NP)/poly (acrylamide-co-acrylic acid) [P(AAm-co-AA)] hydrogel microbeads were successfully prepared using droplet microfluidics technology. The microbeads exhibited a good stimuli-responsive behavior to pH value. Particularly in the pH value ranging from pH 2-pH 9, the composite microbead sizes gradually increased along with the increase of pH value. The homogeneous Au NPs, which were encapsulated in the P(AAm-co-AA) hydrogel microbeads, could transform the volume changes of hydrogel into optical signals by a tested single microbead with a microspectrometre system. The glucose was translated into gluconic acid by glucose oxidase. Thus, the Au NP/P(AAm-co-AA) hydrogel microbeads were used for detecting glucose based on pH effects on the composite microbeads. For this, the single Au NP/P(AAm-co-AA) hydrogel microbead could act as a good pH- or glucose-visualizing sensor.

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

    International Nuclear Information System (INIS)

    Yun, Jumi; Lee, Dae Hoon; Im, Ji Sun; Kim, Hyung-Il

    2012-01-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Jumi [Department of Fine Chemical Engineering and Applied Chemistry, BK21-E2M, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Lee, Dae Hoon [Environment Research Division, Korea Institute of Machinery and Materials, 171 Jang-dong, Yusong-gu, Daejeon 305-343 (Korea, Republic of); Im, Ji Sun [Department of Fine Chemical Engineering and Applied Chemistry, BK21-E2M, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Kim, Hyung-Il, E-mail: hikim@cnu.ac.kr [Department of Fine Chemical Engineering and Applied Chemistry, BK21-E2M, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2012-08-01

    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: Black-Right-Pointing-Pointer High performance of transdermal drug delivery system with an easy control of voltage. Black-Right-Pointing-Pointer Improved thermal response of hydrogel by graphite oxide incorporation. Black-Right-Pointing-Pointer Efficient micro heater fabricated by a joule heating method.

  8. Highly Elastic, Transparent, and Conductive 3D-Printed Ionic Composite Hydrogels

    KAUST Repository

    Odent, Jérémy

    2017-07-17

    Despite extensive progress to engineer hydrogels for a broad range of technologies, practical applications have remained elusive due to their (until recently) poor mechanical properties and lack of fabrication approaches, which constrain active structures to simple geometries. This study demonstrates a family of ionic composite hydrogels with excellent mechanical properties that can be rapidly 3D-printed at high resolution using commercial stereolithography technology. The new material design leverages the dynamic and reversible nature of ionic interactions present in the system with the reinforcement ability of nanoparticles. The composite hydrogels combine within a single platform tunable stiffness, toughness, extensibility, and resiliency behavior not reported previously in other engineered hydrogels. In addition to their excellent mechanical performance, the ionic composites exhibit fast gelling under near-UV exposure, remarkable conductivity, and fast osmotically driven actuation. The design of such ionic composites, which combine a range of tunable properties and can be readily 3D-printed into complex architectures, provides opportunities for a variety of practical applications such as artificial tissue, soft actuators, compliant conductors, and sensors for soft robotics.

  9. Influence of residual composition on the structure and properties of extracellular matrix derived hydrogels.

    Science.gov (United States)

    Claudio-Rizo, Jesús A; Rangel-Argote, Magdalena; Castellano, Laura E; Delgado, Jorge; Mata-Mata, José L; Mendoza-Novelo, Birzabith

    2017-10-01

    In this work, hydrolysates of extracellular matrix (hECM) were obtained from rat tail tendon (TR), bovine Achilles tendon (TAB), porcine small intestinal submucosa (SIS) and bovine pericardium (PB), and they were polymerized to generate ECM hydrogels. The composition of hECM was evaluated by quantifying the content of sulphated glycosaminoglycans (sGAG), fibronectin and laminin. The polymerization process, structure, physicochemical properties, in vitro degradation and biocompatibility were studied and related to their composition. The results indicated that the hECM derived from SIS and PB were significantly richer in sGAG, fibronectin and laminin, than those derived from TAB and TR. These differences in hECM composition influenced the polymerization and the structural characteristics of the fibrillar gel network. Consequently, the swelling, mechanics and degradation of the hydrogels showed a direct relationship with the remaining composition. Moreover, the cytocompatibility and the secretion of transforming growth factor beta-1 (TGF-β1) by macrophages were enhanced in hydrogels with the highest residual content of ECM biomolecules. The results of this work evidenced the role of the ECM molecules remaining after both decellularization and hydrolysis steps to produce tissue derived hydrogels with structure and properties tailored to enhance their performance in tissue engineering and regenerative medicine applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Hierarchically porous composites fabricated by hydrogel templating and viscous trapping techniques

    NARCIS (Netherlands)

    Thompson, Benjamin R.; Horozov, Tommy S.; Stoyanov, Simeon D.; Paunov, Vesselin N.

    2018-01-01

    Two methods for the preparation of hierarchically porous composites have been developed and explored. The first involved templating mixed slurries of hydrogel beads with two different average bead size distributions with gypsum slurry which allows for precise control over the porosity, pore size

  11. Biomimetics of the extracellular matrix: an integrated three-dimensional fiber-hydrogel composite for cartilage tissue engineering

    NARCIS (Netherlands)

    Coburn, J.; Gibson, M.; Bandalini, P.A.; Laird, C.; Mao, H.Q.; Moroni, Lorenzo; Seliktar, D.; Elisseeff, J.H.

    2011-01-01

    The native extracellular matrix (ECM) consists of an integrated fibrous protein network and proteoglycan-based ground (hydrogel) substance. We designed a novel electrospinning technique to engineer a three dimensional fiber-hydrogel composite that mimics the native ECM structure, is injectable, and

  12. Controlled Pesticide Release from Porous Composite Hydrogels Based on Lignin and Polyacrylic Acid

    Directory of Open Access Journals (Sweden)

    Yajie Sun

    2016-01-01

    Full Text Available For the controlled release of pesticides, a novel composite porous hydrogel (LBPAA was prepared based on lignin and polyacrylic acid for use as the support frame of a pore structure for water delivery. The LBPAA was analyzed to determine its water-swelling and slow release properties. The controlled release properties of LBPAA were evaluated through experiments in relation to the cumulative release of pesticides, with particular emphasis on environmental effects and release models. The porous LBPAA hydrogel showed improved properties compared to polyacrylic acid, and could therefore be considered an efficient material for application in controlled release systems in agriculture.

  13. Skin-Inspired Hydrogel-Elastomer Composite with Application in a Moisture Permeable Prosthetic Limb Liner

    Science.gov (United States)

    Ruiz, Esteban

    Recent advances in fields such as 3D printing, and biomaterials, have enabled the development of a moisture permeable prosthetic liner. This project demonstrates the feasibility of the invention by addressing the three primary areas of risk including the mechanical strength, the permeability, and the ability to manufacture. The key enabling technology which allows the liner to operate is the skin inspired hydrogel elastomer composite. The skin inspiration is reflected in the molecular arrangement of the double network of polymers which mimics collagen-elastin toughening in the natural epidermis. A custom formulation for a novel tough double network nanocomposite reinforced hydrogel was developed to improve manufacturability of the liner. The liner features this double network nanocomposite reinforced hydrogel as a permeable membrane which is reinforced on either side by perforated silicone layers manufactured by 3d printing assisted casting. Uniaxial compression tests were conducted on the individual hydrogels, as well as a representative sample of off the shelf prosthetic liners for comparison. Permeability testing was also done on the same set of materials and compared to literature values for traditional hydrogels. This work led to the manufacture of three generations of liner prototypes, with the second and third liner prototype being tested with human participants.

  14. Gentamicin-Loaded Thermosetting Hydrogel and Moldable Composite Scaffold: Formulation Study and Biologic Evaluation.

    Science.gov (United States)

    Dorati, Rossella; De Trizio, Antonella; Genta, Ida; Merelli, Alessia; Modena, Tiziana; Conti, Bice

    2017-06-01

    The aim was to design biodegradable drug delivery systems for gentamicin local delivery, meanwhile acting as scaffold for bone regeneration. Gentamicin-loaded thermosetting composite hydrogels were prepared combining chitosan with bovine bone substitutes (Orthoss® granules), beta-glycerophosphate as cross-linker, and lyophilized to obtain moldable composite scaffolds (moldable composite scaffold loaded with gentamicin [mCSG]). Diverse techniques for gentamicin loading into mCS were investigated by drug incorporation during hydrogel preparation or drug absorption on preformed mCS. Rheologic hydrogel characterization was performed. mCSGs were characterized for porosity, stability (water retention, water uptake), gentamicin release, cell seeding and proliferation, and antimicrobial effect on Escherichia coli ATCC 10356. Results show suitable gentamicin loadings were 4 mg in 1 mL thermosetting composite hydrogel starting solution, irreversible hydrogel thermosetting behavior, and cosolute effect of gentamicin on sol-gel transition. Positive results in terms of porosity (80%-86%), scaffold water uptake, and retention capability were obtained. Antibiotic in vitro release was completed in 4 h. Good cell seeding results were observed for mCSG1-5; mCSG3 and mCSG5 resulted the best as cell proliferation results. mCSG exerted bactericidal effect for 24 h, with superimposition of chitosan bacteriostatic effect in the first 4 h. The results lead to consider the drug delivery for reducing infection risk during bone open surgeries. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  15. Formulation of Thermosensitive Hydrogel Containing Cyclodextrin ...

    African Journals Online (AJOL)

    Materials. Chitosan (deacetylation degree, DDA = 80 %) was obtained from HiMedia Laboratories Pvt. ... Sterile formulations were ... Chilled β-GP aqueous solution (sterilized through ..... generally decreasing away from the center of the tumor.

  16. Selective enrichment and separation of phosphotyrosine peptides by thermosensitive molecularly imprinted polymers.

    Science.gov (United States)

    Yang, Xiaoqing; Xia, Yan

    2016-01-01

    Novel thermosensitive molecularly imprinted polymers were successfully prepared using the epitope imprinting approach in the presence of the mimic template phenylphosphonic acid, the functional monomer vinylphosphonic acid-Ti(4+) , the temperature-sensitive monomer N-isopropylacrylamide and the crosslinker N,N'-methylenebisacrylamide. The ratio of the template/thermosensitive monomers/crosslinker was optimized, and when the ratio was 2:2:1, the prepared thermosensitive molecularly imprinted polymers had the highest imprinting factor. The synthetic thermosensitive molecularly imprinted polymers were characterized by Fourier transform infrared spectroscopy to reveal the combination and elution processes of the template. Then, the adsorption capacity and thermosensitivity was measured. When the temperature was 28°C, the imprinting factor was the highest. The selectivity and adsorption capacity of the thermosensitive molecularly imprinted polymers for phosphotyrosine peptides from a mixture of three tailor-made peptides were measured by high-performance liquid chromatography. The results showed that the thermosensitive molecularly imprinted polymers have good selectivity for phosphotyrosine peptides. Finally, the imprinted hydrogels were applied to specifically adsorb phosphotyrosine peptides from a sample mixture containing phosphotyrosine and a tryptic digest of β-casein, which demonstrated high selectivity. After four rebinding cycles, 78.9% adsorption efficiency was still retained. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Composite hydrogel of chitosan-poly(hydroxybutyrate-co-valerate) with chondroitin sulfate nanoparticles for nucleus pulposus tissue engineering.

    Science.gov (United States)

    Nair, Manitha B; Baranwal, Gaurav; Vijayan, Prajuna; Keyan, Kripa S; Jayakumar, R

    2015-12-01

    Intervertebral disc degeneration, occurring mainly in nucleus pulposus (NP), is a leading cause of low back pain. In seeking to mitigate this condition, investigators in the field of NP tissue engineering have increasingly studied the use of hydrogels. However, these hydrogels should possess appropriate mechanical strength and swelling pressure, and concurrently support the proliferation of chondrocyte-like cells. The objective of this study was to develop and validate a composite hydrogel for NP tissue engineering, made of chitosan-poly(hydroxybutyrate-co-valerate) (CP) with chondroitin sulfate (CS) nanoparticles, without using a cross linker. The water uptake ability, as well as the viscoelastic properties of this composite hydrogel, was similar to native tissue, as reflected in the complex shear modulus and stress relaxation values. The hydrogel could withstand varying stress corresponding to daily activities like lying down (0.01 MPa), sitting (0.5 MPa) and standing (1.0 MPa) under dynamic conditions. The hydrogels were stable in PBS for 2 weeks and its stiffness, elastic and viscous modulus did not alter significantly during this period. Both CP and CP-CS hydrogels could assist the viability and adhesion of adipose derived rat mesenchymal stem cells (ADMSCs). The viability and chondrogenic differentiation of MSCs was significantly enhanced in presence of CS nanoparticles. Thus, CS nanoparticles-incorporated chitosan-PHBV hydrogels offer great potential for NP tissue engineering. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Magnetic Composite Thin Films of FexOy Nanoparticles and Photocrosslinked Dextran Hydrogels

    International Nuclear Information System (INIS)

    Brunsen, Annette; Utech, Stefanie; Maskos, Michael; Knoll, Wolfgang; Jonas, Ulrich

    2012-01-01

    Magnetic hydrogel composites are promising candidates for a broad field of applications from medicine to mechanical engineering. Here, surface-attached composite films of magnetic nanoparticles (MNP) and a polymeric hydrogel (HG) were prepared from magnetic iron oxide nanoparticles and a carboxymethylated dextran with photoreactive benzophenone substituents. A blend of the MNP and the dextran polymer was prepared by mixing in solution, and after spin-coating and drying the blend film was converted into a stable MNP–HG composite by photocrosslinking through irradiation with UV light. The bulk composite material shows strong mobility in a magnetic field, imparted by the MNPs. By utilizing a surface layer of a photoreactive adhesion promoter on the substrates, the MNP–HG films were covalently immobilized during photocrosslinking. The high stability of the composite was documented by rinsing experiments with UV–Vis spectroscopy, while surface plasmon resonance and optical waveguide mode spectroscopy was employed to investigate the swelling behavior in dependence of the nanoparticle concentration, the particle type, and salt concentration. - Highlights: ► blending of iron oxide nanoparticles with photocrosslinkable carboxymethyldextran. ► UV irradiation of blend yields surface-attached, magnetic hydrogel films. ► film characterization by surface plasmon resonance/optical waveguide spectroscopy. ► swelling decreases with increasing nanoparticle content. ► swelling decreases with increasing NaCl salt concentration in the aqueous medium.

  19. Exploration of alginate hydrogel/nano zinc oxide composite bandages for infected wounds

    Directory of Open Access Journals (Sweden)

    Mohandas A

    2015-10-01

    Full Text Available Annapoorna Mohandas,* Sudheesh Kumar PT,* Biswas Raja, Vinoth-Kumar Lakshmanan, Rangasamy Jayakumar Amrita Centre for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham University, Kochi, India *These authors contributed equally to this work Abstract: Alginate hydrogel/zinc oxide nanoparticles (nZnO composite bandage was developed by freeze-dry method from the mixture of nZnO and alginate hydrogel. The developed composite bandage was porous with porosity at a range of 60%–70%. The swelling ratios of the bandages decreased with increasing concentrations of nZnO. The composite bandages with nZnO incorporation showed controlled degradation profile and faster blood clotting ability when compared to the KALTOSTAT® and control bandages without nZnO. The prepared composite bandages exhibited excellent antimicrobial activity against Escherichia coli, Staphylococcus aureus, Candida albicans, and methicillin resistant S. aureus (MRSA. Cytocompatibility evaluation of the prepared composite bandages done on human dermal fibroblast cells by Alamar assay and infiltration studies proved that the bandages have a non-toxic nature at lower concentrations of nZnO whereas slight reduction in viability was seen with increasing nZnO concentrations. The qualitative analysis of ex-vivo re-epithelialization on porcine skin revealed keratinocyte infiltration toward wound area for nZnO alginate bandages. Keywords: alginate, hydrogel, ZnO nanoparticle, hemostatic, antimicrobial activity, wound healing

  20. A novel reducing graphene/polyaniline/cuprous oxide composite hydrogel with unexpected photocatalytic activity for the degradation of Congo red

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Jie; Xie, Anjian; Li, Shikuo; Huang, Fangzhi; Cao, Juan; Shen, Yuhua, E-mail: yhshen@ahu.edu.cn

    2016-01-01

    Graphical abstract: Excellent photocatalytic activity of the RGO/PANI/Cu{sub 2}O composite hydrogel for CR degradation under UV–vis light irradiation. - Highlights: • The RGO/PANI/Cu{sub 2}O composite hydrogel was first synthesized via a facile method. • Photocatalytic performance was studied under UV–vis light. • The ternary composite hydrogel shows unexpected photocatalytic activity. • A possible photocatalysis mechanism was illustrated. - Abstract: In this work, a novel reducing graphene/polyaniline/cuprous oxide (RGO/PANI/Cu{sub 2}O) composite hydrogel with a 3D porous network has been successfully prepared via a one-pot method in the presence of cubic Cu{sub 2}O nanoparticles. The as-synthesized ternary composites hydrogel shows unexpected photocatalytic activity such that Congo red (CR) degradation efficiency can reaches 97.91% in 20 min under UV–vis light irradiation, which is much higher than that of either the single component (Cu{sub 2}O nanoparticles), or two component systems (RGO/Cu{sub 2}O composite hydrogel and PANI/Cu{sub 2}O nanocomposites). Furthermore, the ternary composite hydrogel exhibits high stability and do not show any significant loss after five recycles. Such outstanding photocatalytic activity of the RGO/PANI/Cu{sub 2}O composite hydrogel was ascribed to the high absorption ability of the product for CR and the synergic effect among RGO, PANI and Cu{sub 2}O in photocatalytic process. The product of this work would provide a new sight for the construction of UV–vis light responsive photocatalyst with high performance.

  1. A novel reducing graphene/polyaniline/cuprous oxide composite hydrogel with unexpected photocatalytic activity for the degradation of Congo red

    International Nuclear Information System (INIS)

    Miao, Jie; Xie, Anjian; Li, Shikuo; Huang, Fangzhi; Cao, Juan; Shen, Yuhua

    2016-01-01

    Graphical abstract: Excellent photocatalytic activity of the RGO/PANI/Cu_2O composite hydrogel for CR degradation under UV–vis light irradiation. - Highlights: • The RGO/PANI/Cu_2O composite hydrogel was first synthesized via a facile method. • Photocatalytic performance was studied under UV–vis light. • The ternary composite hydrogel shows unexpected photocatalytic activity. • A possible photocatalysis mechanism was illustrated. - Abstract: In this work, a novel reducing graphene/polyaniline/cuprous oxide (RGO/PANI/Cu_2O) composite hydrogel with a 3D porous network has been successfully prepared via a one-pot method in the presence of cubic Cu_2O nanoparticles. The as-synthesized ternary composites hydrogel shows unexpected photocatalytic activity such that Congo red (CR) degradation efficiency can reaches 97.91% in 20 min under UV–vis light irradiation, which is much higher than that of either the single component (Cu_2O nanoparticles), or two component systems (RGO/Cu_2O composite hydrogel and PANI/Cu_2O nanocomposites). Furthermore, the ternary composite hydrogel exhibits high stability and do not show any significant loss after five recycles. Such outstanding photocatalytic activity of the RGO/PANI/Cu_2O composite hydrogel was ascribed to the high absorption ability of the product for CR and the synergic effect among RGO, PANI and Cu_2O in photocatalytic process. The product of this work would provide a new sight for the construction of UV–vis light responsive photocatalyst with high performance.

  2. Development of a P((MAA-co-NVP)-g-EG) Hydrogel Platform for Oral Protein Delivery: Effects of Hydrogel Composition on Environmental Response and Protein Partitioning.

    Science.gov (United States)

    Steichen, Stephanie; O'Connor, Colleen; Peppas, Nicholas A

    2017-01-01

    Hydrogels based upon terpolymers of methacrylic acid, N-vinyl pyrrolidone, and poly(ethylene glycol) are developed and characterized for their ability to respond to changes in environmental pH and to partition protein therapeutics of varying molecular weights and isoelectric points. P((MAA-co-NVP)-g-EG) hydrogels are synthesized with PEG-based cross-linking agents of varying length and incorporation densities. The composition is confirmed using FT-IR spectroscopy and shows peak shifts indicating hydrogen bonding. Scanning electron microscopy reveals microparticles with an irregular, planar morphology. The pH-responsive behavior of the hydrogels is confirmed under equilibrium and dynamic conditions, with the hydrogel collapsed at acidic pH and swollen at neutral pH. The ability of the hydrogels to partition model protein therapeutics at varying pH and ionic strength is evaluated using three model proteins: insulin, porcine growth hormone, and ovalbumin. Finally, the microparticles are evaluated for adverse interactions with two model intestinal cell lines and show minimal cytotoxicity at concentrations below 5 mg mL -1 . © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Composite Superabsorbent Hydrogel of Acrylic Copolymer and Eggshell: Effect of Biofiller Addition

    OpenAIRE

    Queirós, Marcos Vinícius A.; Bezerra, Maslândia N.; Feitosa, Judith P. A.

    2017-01-01

    Eggshell (ES) is an abundant waste material which is mainly composed of calcium carbonate. A superabsorbent hydrogel composite based on poly(acrylamide-co-potassium acrylate) as matrix containing 17 wt.% of chicken ES powder as a filler was synthesized and compared with the gel without filler. The characterization was carried out by Fourier transform infrared (FTIR), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX), thermogravimetric analysis (TGA), X-ray diffr...

  4. Construction of chitin/PVA composite hydrogels with jellyfish gel-like structure and their biocompatibility.

    Science.gov (United States)

    He, Meng; Wang, Zhenggang; Cao, Yan; Zhao, Yanteng; Duan, Bo; Chen, Yun; Xu, Min; Zhang, Lina

    2014-09-08

    High strength chitin/poly(vinyl alcohol) (PVA) composite hydrogels (RCP) were constructed by adding PVA into chitin dissolved in a NaOH/urea aqueous solution, and then by cross-linking with epichlorohydrin (ECH) and freezing-thawing process. The RCP hydrogels were characterized by field emission scanning electron microscopy, FTIR, differential scanning calorimetry, solid-state (13)C NMR, wide-angle X-ray diffraction, and compressive test. The results revealed that the repeated freezing/thawing cycles induced the bicrosslinked networks consisted of chitin and PVA crystals in the composite gels. Interestingly, a jellyfish gel-like structure occurred in the RCP75 gel with 25 wt % PVA content in which the amorphous and crystalline PVA were immobilized tightly in the chitin matrix through hydrogen bonding interaction. The freezing/thawing cycles played an important role in the formation of the layered porous PVA networks and the tight combining of PVA with the pore wall of chitin. The mechanical properties of RCP75 were much higher than the other RCP gels, and the compressive strength was 20× higher than that of pure chitin gels, as a result of broadly dispersing stress caused by the orderly multilayered networks. Furthermore, the cell culture tests indicated that the chitin/PVA composite hydrogels exhibited excellent biocompatibility and safety, showing potential applications in the field of tissue engineering.

  5. Biological oxygen demand in soils and hydrogel compositions for plant protection of the rhizosphere

    Science.gov (United States)

    Valentinovich Smagin, Andrey

    2018-02-01

    Potential biological activity of mineral and organogenic samples from light-textured sod-podzolic soils as well as of hydrogel compositions for protecting the root layer from pathogenic microflora and unfavorable edaphic factors were studied in laboratory conditions by oxygen consumption under the optimal hydrothermic conditions with portable gas analyzers. We have conducted ecological standardization of biological activity and organic matter destruction estimated by biological oxygen demand (BOD) in the widespread sandy soils. The primary outcome was the scale of gradations of biological oxygen uptake in soils with a range of quantities of potential biological activity from “very low” (140 g·m-3·hour-1), obtained on the basis of statistical processing of data array 1308 measurements. Acrylic polymer hydrogels had BOD = 0.2-2 g·m-3·hour-1, which corresponded to the periods of their half-lives from 0.2±0.1 to 6.8± 4.5 years, or relatively low resistance to biodestruction. In contrast to the pure gels, hydrogel compositions for rhizosphere based on ionic and colloidal silver showed low biological activity (BOD=0.01-0.2 g·m-3· hour-1) and, accordingly, significant resistance to biodegradation with half-lives from 5 to 70 years and above.

  6. Composite hydrogel based on surface modified mesoporous silica and poly[(2-acryloyloxy)ethyl trimethylammonium chloride

    International Nuclear Information System (INIS)

    Torres, Cecilia C.; Urbano, Bruno F.; Campos, Cristian H.; Rivas, Bernabé L.; Reyes, Patricio

    2015-01-01

    This work focused on the synthesis, characterization and water absorbency of a composite hydrogel based on poly[(2-acryloyloxy)ethyl trimethylammonium chloride] and mesoporous silica, MCM-41. The MCM-41 was synthesized and later surface functionalized with triethoxyvinylsilane (VTES) and 3-trimethoxysilylpropylmethacrylate (TMSPM) by a post-grafting procedure. The composite hydrogels were obtained by in-situ polymerization using a mixture of monomer, crosslinker and initiator in the presence of functionalized MCM-41. Diverse characterization techniques were used at the different stages of synthesis, namely, FT-IR, TEM, SEM, DRX, 29 Si and 13 C solid state NMR, and N 2 adsorption isotherms at 77 K. Finally, the water uptake performance of the composites was tested as a function of time, mesoporous silica loading and coupling agent used at the functionalization. The composites using non-functionalized MCM-41 reached the highest water uptake, whereas those composite with MCM-41 TMSPM exhibited the lowest sorption. - Highlights: • Hydrophilic crosslinked polymer-mesoporous silica was obtained. • Mesoporous silica MCM-41 was synthesized and functionalized with organosilane. • Functionalization of MCM-41 affects the water uptake of composite. • Mesoporous silica is covalently bound to the polymer acting as crosslinked point

  7. Composite hydrogel based on surface modified mesoporous silica and poly[(2-acryloyloxy)ethyl trimethylammonium chloride

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Cecilia C. [Department of Organic Chemistry, Faculty of Chemical Science, University of Concepción (Chile); Urbano, Bruno F., E-mail: burbano@udec.cl [Department of Polymer Chemistry, Faculty of Chemical Science, University of Concepción (Chile); Campos, Cristian H. [Department of Organic Chemistry, Faculty of Chemical Science, University of Concepción (Chile); Rivas, Bernabé L. [Department of Polymer Chemistry, Faculty of Chemical Science, University of Concepción (Chile); Reyes, Patricio [Department of Physical Chemistry, Faculty of Chemical Science, University of Concepción (Chile)

    2015-02-15

    This work focused on the synthesis, characterization and water absorbency of a composite hydrogel based on poly[(2-acryloyloxy)ethyl trimethylammonium chloride] and mesoporous silica, MCM-41. The MCM-41 was synthesized and later surface functionalized with triethoxyvinylsilane (VTES) and 3-trimethoxysilylpropylmethacrylate (TMSPM) by a post-grafting procedure. The composite hydrogels were obtained by in-situ polymerization using a mixture of monomer, crosslinker and initiator in the presence of functionalized MCM-41. Diverse characterization techniques were used at the different stages of synthesis, namely, FT-IR, TEM, SEM, DRX, {sup 29}Si and {sup 13}C solid state NMR, and N{sub 2} adsorption isotherms at 77 K. Finally, the water uptake performance of the composites was tested as a function of time, mesoporous silica loading and coupling agent used at the functionalization. The composites using non-functionalized MCM-41 reached the highest water uptake, whereas those composite with MCM-41 TMSPM exhibited the lowest sorption. - Highlights: • Hydrophilic crosslinked polymer-mesoporous silica was obtained. • Mesoporous silica MCM-41 was synthesized and functionalized with organosilane. • Functionalization of MCM-41 affects the water uptake of composite. • Mesoporous silica is covalently bound to the polymer acting as crosslinked point.

  8. Acceleration of gelation and promotion of mineralization of chitosan hydrogels by alkaline phosphatase

    NARCIS (Netherlands)

    Douglas, T.E.L.; Skwarczynska, A.; Modrzejewska, Z.; Balcaen, L.; Schaubroeck, D.; Lycke, S.; Vanhaecke, F.; Vandenabeele, P.; Dubruel, P.; Jansen, J.A.; Leeuwenburgh, S.C.G.

    2013-01-01

    Thermosensitive chitosan hydrogels containing sodium beta-glycerophosphate (beta-GP), whose gelation is induced by increasing temperature to body temperature, were functionalized by incorporation of alkaline phosphatase (ALP), an enzyme involved in mineralization of bone. ALP incorporation led to

  9. Evaluating a simple blending approach to prepare magnetic and stimuli-responsive composite hydrogel particles for application in biomedical field

    Directory of Open Access Journals (Sweden)

    H. Ahmad

    2016-08-01

    Full Text Available The inclusion of super paramagnetic iron oxide (Fe3O4 nanoparticles in stimuli-responsive hydrogel is expected to enhance the application potential for cellular therapy in cell labeling, separation and purification, protein immobilization, contrasting enhancement in magnetic resonance imaging (MRI, localized therapeutic hyperthermia, biosensors etc. in biomedical field. In this investigation two different magnetic and stimuli-responsive composite hydrogel particles with variable surface property were prepared by simply blending Fe3O4/SiO2 nanocomposite particles with stimuli-responsive hydrogel particles. Of the hydrogel particles prepared by free-radical precipitation polymerization poly(styrene-N-isopropylacrylamide-methyl methacrylate-polyethylene glycol methacrylate or P(S-NIPAM-MMA-PEGMA was temperature-sensitive and poly(S-NIPAM-methacrylic acid-PEGMA or P(S-NIPAM-MAA-PEGMA was both temperature- and pH-responsive. The morphological structure, size distributions and volume phase transitions of magnetic and stimuli-responsive composite hydrogel particles were analyzed. Temperature-responsive absorptions of biomolecules were observed on both magnetic and stimuli-responsive Fe3O4/SiO2/P(S-NIPAM-MMA-PEGMA and Fe3O4/SiO2/P(S-NIPAM-MAA-PEGMA composite hydrogel particles and separation of particles from the dispersion media could be achieved by applying magnetic field without time consuming centrifugation or decantation method.

  10. Electromechanical response of silk fibroin hydrogel and conductive polycarbazole/silk fibroin hydrogel composites as actuator material.

    Science.gov (United States)

    Srisawasdi, Thanida; Petcharoen, Karat; Sirivat, Anuvat; Jamieson, Alexander M

    2015-11-01

    Pure silk fibroin (SF) hydrogel and polycarbazole/silk fibroin (SF/PCZ) hydrogels were fabricated by solvent casting technique to evaluate electromechanical responses, dielectric properties, and cantilever deflection properties as functions of electric field strength, SF concentration, glutaraldehyde concentration, and PCZ concentration in the blends. Electromechanical properties were characterized in oscillatory shear mode at electric field strengths ranging from 0 to 600V/mm and at a temperature of 27°C. For both the pristine SF and SF/PCZ hydrogels, the storage modulus response (ΔG') and the storage modulus sensitivity (ΔG'/G'0) increased dramatically with increasing electric field strength. The pristine hydrogel possessed the highest storage modulus sensitivity value of 5.87, a relatively high value when compared with other previously studied electroactive polymers. With the addition of conductive PCZ in SF hydrogel, the storage modulus sensitivity and the relative dielectric constant decreased; the conductive polymer thus provided the softening effect under electric field. In the deflection response, the dielectrophoresis force and deflection distance increased monotonically with electric field strength, where the pure SF hydrogel showed the highest deflection distance and dielectrophoresis force. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Synthesis of a biocopolymer carrageenan-g-poly(AAm-co-IA/ montmorilonite superabsorbent hydrogel composite

    Directory of Open Access Journals (Sweden)

    M. Sadeghi

    2012-06-01

    Full Text Available A novel superabsorbent hydrogel composite based on kappa-carrageenan (κC has been prepared via graft copolymerization of acrylamide (AAm and itaconic acid (IA monomers in the presence of montmorolonite clay powder, methylenebisacrylamide (MBA as the crosslinking agent and ammonium persulfate (APS as initiator. Evidence of grafting and montmorolonite interaction was obtained by comparison of FTIR and TGA spectra of the initial substrates and the superabsorbent composite. A new absorption band at 1722 cm-1 in the composite spectrum confirmed montmorolonite-organic polymer linkages. Moreover, the morphology of the samples was examined by scanning electron microscopy (SEM. The swelling of the superabsorbing hydrogels was also examined in solutions with pH values ranging between 1.0 and 13.0. Finally, the swelling behavior of these composite polymers was investigated in various salt solutions. Results indicated that the swelling capacity decreased with an increase in the ionic strength of the swelling medium. This behavior can be attributed to the charge screening effect of monovalent cations, as well as ionic crosslinking for multivalent cations.

  12. NOVEL SUPERABSORBENT HYDROGEL COMPOSITE BASED ON POLY(ACRYLAMIDE-CO-ACRYLATE/NONTRONITE: CHARACTERIZATION AND SWELLING PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Renan C. F. Leitão

    2015-03-01

    Full Text Available A novel superabsorbent hydrogel (SH composite based on a poly(acrylamide-co-acrylate matrix filled with nontronite (NONT, a Fe(III-rich member of the smectite group of clay minerals, is described in this manuscript. A variety of techniques, including FTIR, XRD, TGA, and SEM/EDX, were utilized to characterize this original composite. Experimental data confirmed the SH composite formation and suggested NONT was completely dispersed in the polymeric matrix. Additionally, NONT improved the water uptake capacity of the final material, which exhibited fast absorption, low sensitivity to the presence of salt, high water retention and a pH sensitive properties. These preliminary data showed that the original SH composite prepared here possesses highly attractive properties for applications in areas such as the agriculture field, particularly as a soil conditioner.

  13. Novel composite sorbent AAm/MA hydrogels containing starch and ...

    Indian Academy of Sciences (India)

    A novel polymer/clay composite sorbent based on acrylamide/maleic acid, starch and clay such as kaolin was synthesized with free radical solution polymerization by using ammonium persulfate/,,','-tetramethylethylenediamine as redox initiating pair in the presence of poly(ethylene glycol)diacrylate as a crosslinker.

  14. Belousov Zhabotinsky Autonomic Hydrogel Composites: Regulating Waves via Asymmetry (Postprint)

    Science.gov (United States)

    2016-09-23

    Zhabotinsky (BZ)‐gelatin composites by synchronicity. Adv. Funct. Mater. 23, 2835–2842 (2013). 6. R. Yoshida, T. Takahashi, T. Yamaguchi , H. Ichijo, Self...2014). 12. R. Yoshida, M. Tanaka, S. Onodera, T. Yamaguchi , E. Kokufuta, In-phase synchronization of chemical and mechanical oscillations in self

  15. Strong composite films with layered structures prepared by casting silk fibroin-graphene oxide hydrogels

    Science.gov (United States)

    Huang, Liang; Li, Chun; Yuan, Wenjing; Shi, Gaoquan

    2013-04-01

    Composite films of graphene oxide (GO) sheets and silk fibroin (SF) with layered structures have been prepared by facile solution casting of SF-GO hydrogels. The as-prepared composite film containing 15% (by weight, wt%) of SF shows a high tensile strength of 221 +/- 16 MPa and a failure strain of 1.8 +/- 0.4%, which partially surpass those of natural nacre. Particularly, this composite film also has a high modulus of 17.2 +/- 1.9 GPa. The high mechanical properties of this composite film can be attributed to its high content of GO (85 wt%), compact layered structure and the strong hydrogen bonding interaction between SF chains and GO sheets.Composite films of graphene oxide (GO) sheets and silk fibroin (SF) with layered structures have been prepared by facile solution casting of SF-GO hydrogels. The as-prepared composite film containing 15% (by weight, wt%) of SF shows a high tensile strength of 221 +/- 16 MPa and a failure strain of 1.8 +/- 0.4%, which partially surpass those of natural nacre. Particularly, this composite film also has a high modulus of 17.2 +/- 1.9 GPa. The high mechanical properties of this composite film can be attributed to its high content of GO (85 wt%), compact layered structure and the strong hydrogen bonding interaction between SF chains and GO sheets. Electronic supplementary information (ESI) available: XPS spectrum of the SF-GO hybrid film, SEM images of lyophilized GO dispersion and the failure surface of GO film. See DOI: 10.1039/c3nr00196b

  16. Self-assembled high-strength hydroxyapatite/graphene oxide/chitosan composite hydrogel for bone tissue engineering.

    Science.gov (United States)

    Yu, Peng; Bao, Rui-Ying; Shi, Xiao-Jun; Yang, Wei; Yang, Ming-Bo

    2017-01-02

    Graphene hydrogel has shown greatly potentials in bone tissue engineering recently, but it is relatively weak in the practical use. Here we report a facile method to synthesize high strength composite graphene hydrogel. Graphene oxide (GO), hydroxyapatite (HA) nanoparticles (NPs) and chitosan (CS) self-assemble into a 3-dimensional hydrogel with the assistance of crosslinking agent genipin (GNP) for CS and reducing agent sodium ascorbate (NaVC) for GO simultaneously. The dense and oriented microstructure of the resulted composite gel endows it with high mechanical strength, high fixing capacity of HA and high porosity. These properties together with the good biocompatibility make the ternary composite gel a promising material for bone tissue engineering. Such a simultaneous crosslinking and reduction strategy can also be applied to produce a variety of 3D graphene-polymer based nanocomposites for biomaterials, energy storage materials and adsorbent materials. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Surface-enhanced Raman scattering on molecular self-assembly in nanoparticle-hydrogel composite.

    Science.gov (United States)

    Miljanić, Snezana; Frkanec, Leo; Biljan, Tomislav; Meić, Zlatko; Zinić, Mladen

    2006-10-24

    Surface-enhanced Raman scattering has been applied to study weak intermolecular interactions between small organic gelling molecules involved in the silver nanoparticle-hydrogel composite formation. Assembly and disassembly of the gelator molecules in close vicinity to embedded silver nanoparticles were followed by changes in Raman intensity of the amide II and carboxyl vibrational bands, whereas the strength of the bands related to benzene modes remained constant. This implied that the gelator molecules were strongly attached to the silver particles through the benzene units, while participating in gel structure organization by intermolecular hydrogen bonding between oxalyl amide and carboxyl groups.

  18. Biomimetically-mineralized composite coatings on titanium functionalized with gelatin methacrylate hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Guoxin, E-mail: tanguoxin@126.com [School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006 (China); Zhou, Lei [School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006 (China); Ning, Chengyun, E-mail: imcyning@scut.edu.cn [College of Materials Science and Technology, South China University of Technology, Guangzhou, 510641 (China); Tan, Ying [School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006 (China); Ni, Guoxin [Department of Orthopedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515 (China); Liao, Jingwen; Yu, Peng; Chen, Xiaofeng [College of Materials Science and Technology, South China University of Technology, Guangzhou, 510641 (China)

    2013-08-15

    Immobilizing organic–inorganic hybrid composites onto the implant surface is a promising strategy to improve host acceptance of the implant. The objective of this present study was to obtain a unique macroporous titanium-surface with the organic–mineral composite coatings consisting of gelatin methacrylate hydrogel (GelMA) and hydroxyapatite (HA). A 3-(trimethoxysilyl) propyl methacrylate (TMSPMA) layer was first coated onto the titanium surface, and surface was then covalently functionalized with GelMA using a photochemical method. Mineralization of the GelMA coating on the titanium surface was subsequently carried out by a biomimetic method. After 3-day mineralization, a large number of mineral phases comprising spherical amorphous nanoparticles were found randomly deposited inside GelMA matrix. The resulting mineralized hydrogel composites exhibited a unique rough surface of macroporous structure. The structure of the prepared GelMA/HA composite coating was studied by field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectra (EDS), attenuated total refraction Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Water contact angle measurement revealed the hydrophilicity properties of composite coatings. GelMA/HA on titanium after the TMSPMA treatment is very stable when tested in vitro with a PBS solution at 37 °C, due to the role of TMSPMA as a molecular bridge. It was expected that the macroporous GelMA/HA composite coatings might potentially promote and accelerate titanium (Ti)-based implants osseointegration for bone repair and regeneration.

  19. N-isopropylacrylamide-based fine-dispersed thermosensitive ferrogels obtained via in-situ technique.

    Science.gov (United States)

    Korotych, O; Samchenko, Yu; Boldeskul, I; Ulberg, Z; Zholobak, N; Sukhodub, L

    2013-03-01

    Thermosensitive hydrogels with magnetic properties (ferrogels) are very promising for medical application, first of all, for the design of targeted delivery systems with controlled release of drugs and for magnetic hyperthermia and chemotherapy treatment of cancer. These magnetic hydrogels could be obtained using diverse techniques: ex- and in-situ syntheses. The present work is devoted to the study of magnetite (Fe(3)O(4)) formation inside the nanoreactors of (co)polymeric hydrogels. Polymeric templates (hydrogel films and fine-dispersed hydrogels) used for obtaining ferrogels were based on acrylic monomers: thermosensitive N-isopropylacrylamide, and hydrophilic acrylamide. Covalent cross-linking was accomplished using bifunctional monomer N,N'-methylenebisacrylamide. Influence of hydrophilic-lipophilic balance of polymeric templates and concentration of iron cations on the magnetite formation were investigated along with the development of ferrogel preparation technique. Cytotoxicity, physical and chemical properties of obtained magnetic hydrogels have been studied in this work. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Accelerated in vitro release testing of implantable PLGA microsphere/PVA hydrogel composite coatings.

    Science.gov (United States)

    Shen, Jie; Burgess, Diane J

    2012-01-17

    Dexamethasone loaded poly(lactic-co-glycolic acid) (PLGA) microsphere/PVA hydrogel composites have been investigated as an outer drug-eluting coating for implantable devices such as glucose sensors to counter negative tissue responses to implants. The objective of this study was to develop a discriminatory, accelerated in vitro release testing method for this drug-eluting coating using United States Pharmacopeia (USP) apparatus 4. Polymer degradation and drug release kinetics were investigated under "real-time" and accelerated conditions (i.e. extreme pH, hydro-alcoholic solutions and elevated temperatures). Compared to "real-time" conditions, the initial burst and lag phases were similar using hydro-alcoholic solutions and extreme pH conditions, while the secondary apparent zero-order release phase was slightly accelerated. Elevated temperatures resulted in a significant acceleration of dexamethasone release. The accelerated release data were able to predict "real-time" release when applying the Arrhenius equation. Microsphere batches with faster and slower release profiles were investigated under "real-time" and elevated temperature (60°C) conditions to determine the discriminatory ability of the method. The results demonstrated both the feasibility and the discriminatory ability of this USP apparatus 4 method for in vitro release testing of drug loaded PLGA microsphere/PVA hydrogel composites. This method may be appropriate for similar drug/device combination products and drug delivery systems. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Symbiosis of zeolite-like metal-organic frameworks (rho-ZMOF) and hydrogels: Composites for controlled drug release

    KAUST Repository

    Ananthoji, Ramakanth

    2011-01-01

    The design and synthesis of new finely tunable porous materials has spurred interest in developing novel uses in a variety of systems. Zeolites, inorganic materials with high thermal and mechanical stability, in particular, have been widely examined for use in applications such as catalysis, ion exchange and separation. A relatively new class of inorganic-organic hybrid materials known as metal-organic frameworks (MOFs) have recently surfaced, and many have exhibited their efficiency in potential applications such as ion exchange and drug delivery. A more recent development is the design and synthesis of a subclass of MOFs based on zeolite topologies (i.e. ZMOFs), which often exhibit traits of both zeolites and MOFs. Bio-compatible hydrogels already play an important role in drug delivery systems, but are often limited by stability issues. Thus, the addition of ZMOFs to hydrogel formulations is expected to enhance the hydrogel mechanical properties, and the ZMOF-hydrogel composites should present improved, symbiotic drug storage and release for delivery applications. Herein we present the novel composites of a hydrogel with a zeolite-like metal-organic framework, rho-ZMOF, using 2-hydroxyethyl methacrylate (HEMA), 2,3-dihydroxypropyl methacrylate (DHPMA), N-vinyl-2-pyrolidinone (VP) and ethylene glycol dimethacrylate (EGDMA), and the corresponding drug release. An ultraviolet (UV) polymerization method is employed to synthesize the hydrogels, VP 0, VP 15, VP 30, VP 45 and the ZMOF-VP 30 composite, by varying the VP content (mol%). The rho-ZMOF, VP 30, and ZMOF-VP 30 composite are all tested for the controlled release of procainamide (protonated, PH), an anti-arrhythmic drug, in phosphate buffer solution (PBS) using UV spectroscopy. © 2011 The Royal Society of Chemistry.

  2. Implantable bladder volume sensor based on resistor ladder network composed of conductive hydrogel composite.

    Science.gov (United States)

    Mi Kyung Kim; Hyojung Kim; Jung, Yeon Su; Adem, Kenana M A; Bawazir, Sarah S; Stefanini, Cesare; Lee, Hyunjoo J

    2017-07-01

    An accurate bladder volume monitoring system is a critical component in diagnosis and treatment of urological disorders. Here, we report an implantable bladder volume sensor with a multi-level resistor ladder which estimates the bladder volume through discrete resistance values. Discretization allows the sensor output to be resilient to the long-term drift, hysteresis, and degradation of the sensor materials. Our sensor is composed of biocompatible polypyrrole/agarose hydrogel composite. Because Young's modulus of this composite is comparable to that of the bladder wall, the effect of mechanical loading of the sensor on the bladder movement is minimized which allows more accurate volume monitoring. We also demonstrate the patterning and molding capability of this material by fabrication various structures. Lastly, we successfully demonstrate the functionality of the multi-level resistor ladder sensor as a bladder volume sensor by attaching the sensor on the pig's bladder and observing the impedance change of the sensor.

  3. Structural characterization and anti-cancerous potential of gallium bioactive glass/hydrogel composites.

    Science.gov (United States)

    Keenan, T J; Placek, L M; Coughlan, A; Bowers, G M; Hall, M M; Wren, A W

    2016-11-20

    A bioactive glass series (0.42SiO2-0.10Na2O-0.08CaO-(0.40-X)ZnO-(X)Ga2O3) was incorporated into carboxymethyl cellulose (CMC)/dextran (Dex) hydrogels in three different amounts (0.05, 0.10, and 0.25m(2)), and the resulting composites were characterized using transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and (13)C Cross Polarization Magic Angle Spinning Nuclear Magnetic Resonance (CP MAS-NMR). Composite extracts were also evaluated in vitro against MG-63 osteosarcoma cells. TEM confirmed glass distribution throughout the composites, although some particle agglomeration was observed. DSC revealed that glass composition and content did have small effects on both Tg and Tm. MAS-NMR revealed that both CMC and Dex were successfully functionalized, that cross-linking occurred, and that glass addition did slightly alter bonding environments. Cell viability analysis suggested that extracts of the glass and composites with the largest Ga-content significantly decreased MG-63 osteosarcoma viability after 30days. This study successfully characterized this composite series, and demonstrated their potential for anti-cancerous applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Electro-mechanical properties of hydrogel composites with micro- and nano-cellulose fillers

    International Nuclear Information System (INIS)

    Shahid U N, Mohamed; Deshpande, Abhijit P; Rao, C Lakshmana

    2015-01-01

    Stimuli responsive cross-linked hydrogels are of great interest for applications in diverse fields such as sensors and biomaterials. In this study, we investigate polymer composites filled with cellulose fillers. The celluloses used in making the composites were a microcrystalline cellulose of commercial grade and cellulose nano-whiskers obtained through acid hydrolysis of microcrystalline cellulose. The filler concentration was varied and corresponding physical, mechanical and electro-mechanical characterization was carried out. The electro-mechanical properties were determined using a quasi-static method. The fillers not only enhance the mechanical properties of the composite by providing better reinforcement but also provide a quantitative electric potential in the composite. The measurements reveal that the polymer composites prepared from two different cellulose fillers possess a quantitative electric potential which can be utilized in biomedical applications. It is argued that the mechanism behind the quantitative electric potential in the composites is due to streaming potentials arising due to electrical double layer formation. (paper)

  5. In vitro-ex vivo correlations between a cell-laden hydrogel and mucosal tissue for screening composite delivery systems.

    Science.gov (United States)

    Blakney, Anna K; Little, Adam B; Jiang, Yonghou; Woodrow, Kim A

    2016-11-01

    Composite delivery systems where drugs are electrospun in different layers and vary the drug stacking-order are posited to affect bioavailability. We evaluated how the formulation characteristics of both burst- and sustained-release electrospun fibers containing three physicochemically diverse drugs: dapivirine (DPV), maraviroc (MVC) and tenofovir (TFV) affect in vitro and ex vivo release. We developed a poly(hydroxyethyl methacrylate) (pHEMA) hydrogel release platform for the rapid, inexpensive in vitro evaluation of burst- and sustained-release topical or dermal drug delivery systems with varying microarchitecture. We investigated properties of the hydrogel that could recapitulate ex vivo release into nonhuman primate vaginal tissue. Using a dimethyl sulfoxide extraction protocol and high-performance liquid chromatography analysis, we achieved >93% recovery from the hydrogels and >88% recovery from tissue explants for all three drugs. We found that DPV loading, but not stacking order (layers of fiber containing a single drug) or microarchitecture (layers with isolated drug compared to all drugs in the same layer) impacted the burst release in vitro and ex vivo. Our burst-release formulations showed a correlation for DPV accumulation between the hydrogel and tissue (R 2 =   0.80), but the correlation was not significant for MVC or TFV. For the sustained-release formulations, the PLGA/PCL content did not affect TFV release in vitro or ex vivo. Incorporation of cells into the hydrogel matrix improved the correlation between hydrogel and tissue explant release for TFV. We expect that this hydrogel-tissue mimic may be a promising preclinical model to evaluate topical or transdermal drug delivery systems with complex microarchitectures.

  6. Cost-Effective Double-Layer Hydrogel Composites for Wound Dressing Applications

    Directory of Open Access Journals (Sweden)

    Javad Tavakoli

    2018-03-01

    Full Text Available Although poly vinyl alcohol-poly acrylic acid (PVA-PAA composites have been widely used for biomedical applications, their incorporation into double-layer assembled thin films has been limited because the interfacial binding materials negatively influence the water uptake capacity of PVA. To minimize the effect of interfacial binding, a simple method for the fabrication of a double-layered PVA-PAA hydrogel was introduced, and its biomedical properties were evaluated in this study. Our results revealed that the addition of PAA layers on the surface of PVA significantly increased the swelling properties. Compared to PVA, the equilibrium swelling ratio of the PVA-PAA hydrogel increased (p = 0.035 and its water vapour permeability significantly decreased (p = 0.04. Statistical analysis revealed that an increase in pH value from 7 to 10 as well as the addition of PAA at pH = 7 significantly increased the adhesion force (p < 0.04. The mechanical properties—including ultimate tensile strength, modulus, and elongation at break—remained approximately untouched compared to PVA. A significant increase in biocompatibility was found after day 7 (p = 0.016. A higher release rate for tetracycline was found at pH = 8 compared to neutral pH.

  7. Influence of clay particles on microfluidic-based preparation of hydrogel composite microsphere

    Science.gov (United States)

    Hong, Joung Sook

    2016-05-01

    For the successful fabrication of a hydrogel composite microsphere, this study aimed to investigate the influence of clay particles on microsphere formation in a microfluidic device which has flow focusing and a 4.5:1 contraction channel. A poly alginic acid solution (2.0 wt.%) with clay particles was used as the dispersed phase to generate drops in an oil medium, which then merged with drops of a CaCl2 solution for gelation. Drop generations were observed with different flow rates and particles types. When the flow rate increased, drop generation was enhanced and drop size decreased by the build-up of more favorable hydrodynamic flow conditions to detach the droplets. The addition of a small amount of particles insignificantly changed the drop generation behavior even though it reduced interfacial tension and increased the viscosity of the solution. Instead, clays particles significantly affected hydro-gelation depending on the hydrophobicity of particles, which produced further heterogeneity in the shape and size of microsphere.

  8. Characterization of elasticity and hydration of composite hydrogel based on collagen-iota carrageenan as a corneal tissue engineering

    Science.gov (United States)

    Rinawati, M.; Triastuti, J.; Pursetyo, K. T.

    2018-04-01

    The cornea is a refractive element of the eye that serves to continue the stimulation of light into the eye it has a clear, transparent, elastic and relatively thick tissue. Factors caused corneal blindness, are dystrophy, keratoconus, corneal scaring. Hydrogels can be made from polysaccharide derivatives that have gelation properties such as iota carrageenan. Therefore, it is a need to develop composite hydrogel based collagen-iota carragenan as an engineeried corneal tissue with high elasticity and hydration properties. Collagen hydrogel has a maximum water content an has equlibrium up to 40 %, less than the human cornea, 81 % and under normal hydration conditions, the human cornea can transmit 87 % of visible light. In addition, the refractive index on the surface of the cornea with air is 1.375-1.380. Based on this study, it is necessary to conduct research on the development and composition of hydrogel composite collagen-iota carrageen hydrogen based on. The best result was K5 (5:5) treatment, which has the equilibrium water content of 87.07 % and viscosity of 10.7346 Pa.s.

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

    Directory of Open Access Journals (Sweden)

    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.

  10. Synthesis and characterization of nanosilver-silicone hydrogel composites for inhibition of bacteria growth.

    Science.gov (United States)

    Helaly, F M; El-Sawy, S M; Hashem, A I; Khattab, A A; Mourad, R M

    2017-02-01

    Nanosilver-silicone hydrogel (NAgSiH) composites for contact lenses were synthesized to asses the antimicrobial effects. Silicone hydrogel (SiH) films were synthesized followed by impregnation in silver nitrate solutions (10, 20, 30, 40, 60, 80ppm) and in-situ chemical reduction of silver ions using sodium borohydride (NaBH 4 ). The silver nano particles (AgNPS) were identified by UV-vis absorption spectroscopy, Energy-dispersive X-ray spectroscopy (EDX) mapping and EDX spectrum. Physico-mechanical and chemical properties of NAgSIH films were studied. The antimicrobial effect of the hydrogels against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus was evaluated. The numbers of viable bacterial cells on NAgSiH surface or in solution compared to control SiH were examined. The NAgSiH films were successfully synthesized. FTIR results indicated that AgNPS had no effect on the bulk structure of the prepared SiH films. From TGA analysis, NAgSiH(R80) and SiH(R0) films had the same maximum decomposition temperature (404°C). UV-vis absorption spectroscopy and EDX mapping and spectrum emphasized that AgNPS were in spherical shape. The maximum absorption wavelength of NAgSiH films were around 400nm. The light transmittance decreased as the concentration of AgNPS increased, but still greater than 90% at wavelength around 555nm. The Young's modulus increased gradually from 1.06MPa of SiH(R0) to highest value 1.38MPa of NAgSiH(R80). AgNPS incorporated into SiH films reduced the bacterial cell growth and prevented colonization. Groups NAgSiH(R60,R80) demonstrated an excellent reduction in bacterial viability in solution and on the SiH surface. NAgSiH composites were successfully synthesized and possessed an excellent antimicrobial effects. Copyright © 2016 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2015-03-20

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

  12. Magnetic Composite Thin Films of Fe{sub x}O{sub y} Nanoparticles and Photocrosslinked Dextran Hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Brunsen, Annette, E-mail: brunsen@mpip-mainz.mpg.de [Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz (Germany); Department of Chemistry, Technical University Darmstadt, Petersenstr. 22, 64287 Darmstadt (Germany); Utech, Stefanie, E-mail: utech@uni-mainz.de [Johannes Gutenberg University Mainz, Institute of Physical Chemistry, Jakob-Welder-Weg 11, 55099 Mainz (Germany); Institut fuer Mikrotechnik Mainz GmbH (IMM), Carl-Zeiss-Str. 18-20, 55129 Mainz, German (Germany); Maskos, Michael, E-mail: maskos@uni-mainz.de [Institut fuer Mikrotechnik Mainz GmbH (IMM), Carl-Zeiss-Str. 18-20, 55129 Mainz, German (Germany); Knoll, Wolfgang, E-mail: Wolfgang.Knoll@ait.ac.at [Austrian Institute of Technology, Tech Gate Vienna, Donau-City-Str. 1, 1220 Wien (Austria); Jonas, Ulrich, E-mail: jonas@mpip-mainz.mpg.de [Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz (Germany) and Macromolecular Chemistry, Department Chemistry - Biology, University of Siegen, Adolf-Reichwein-Str. 2, 57076 Siegen (Germany) and Foundation for Research and Technology - Hellas - FORTH, Institute of Electronic Structure and Laser (IESL), Bio-Organic Materials Chemistry Laboratory - BOMCLab, Nikolaou Plastira 100, Vassilika Vouton, 71110 Heraklion, Crete (Greece)

    2012-04-15

    Magnetic hydrogel composites are promising candidates for a broad field of applications from medicine to mechanical engineering. Here, surface-attached composite films of magnetic nanoparticles (MNP) and a polymeric hydrogel (HG) were prepared from magnetic iron oxide nanoparticles and a carboxymethylated dextran with photoreactive benzophenone substituents. A blend of the MNP and the dextran polymer was prepared by mixing in solution, and after spin-coating and drying the blend film was converted into a stable MNP-HG composite by photocrosslinking through irradiation with UV light. The bulk composite material shows strong mobility in a magnetic field, imparted by the MNPs. By utilizing a surface layer of a photoreactive adhesion promoter on the substrates, the MNP-HG films were covalently immobilized during photocrosslinking. The high stability of the composite was documented by rinsing experiments with UV-Vis spectroscopy, while surface plasmon resonance and optical waveguide mode spectroscopy was employed to investigate the swelling behavior in dependence of the nanoparticle concentration, the particle type, and salt concentration. - Highlights: Black-Right-Pointing-Pointer blending of iron oxide nanoparticles with photocrosslinkable carboxymethyldextran. Black-Right-Pointing-Pointer UV irradiation of blend yields surface-attached, magnetic hydrogel films. Black-Right-Pointing-Pointer film characterization by surface plasmon resonance/optical waveguide spectroscopy. Black-Right-Pointing-Pointer swelling decreases with increasing nanoparticle content. Black-Right-Pointing-Pointer swelling decreases with increasing NaCl salt concentration in the aqueous medium.

  13. Physically crosslinked composite hydrogels of PVA with natural macromolecules: structure, mechanical properties, and endothelial cell compatibility.

    Science.gov (United States)

    Liu, Y; Vrana, N E; Cahill, P A; McGuinness, G B

    2009-08-01

    Polyvinyl alcohol (PVA) hydrogels have been considered potentially suitable for applications as engineered blood vessels because of their structure and mechanical properties. However, PVA's hydrophilicity hinders its capacity to act as a substrate for cell attachment. As a remedy, PVA was blended with chitosan, gelatin, or starch, and hydrogels were formed by subjecting the solutions to freeze-thaw cycles followed by coagulation bath immersion. The structure-property relationships for these hydrogels were examined by measurement of their swelling, rehydration, degradation, and mechanical properties. For the case of pure PVA hydrogels, the equilibrium swelling ratio was used to predict the effect of freeze thaw cycles and coagulation bath on average molecular weights between crosslinks and on mesh size. For all hydrogels, trends for the reswelling ratio, which is indicative of the crosslinked polymer fraction, were consistent with relative tensile properties. The coagulation bath treatment increased the degradation resistance of the hydrogels significantly. The suitability of each hydrogel for cell attachment and proliferation was examined by protein adsorption and bovine vascular endothelial cell culture experiments. Protein adsorption and cell proliferation was highest on the PVA/gelatin hydrogels. This study demonstrates that the potential of PVA hydrogels for artificial blood vessel applications can be improved by the addition of natural polymers, and that freeze-thawing and coagulation bath treatment can be utilized for fine adjustment of the physical characteristics.

  14. [Securing the use of thermosensitive drugs].

    Science.gov (United States)

    Castel, Camille; Saint-Lorant, Guillaume

    2015-10-01

    The safety of patient care entails complying with the temperature requirements for thermosensitive drugs. Field studies carried out at the CHU de Caen University Hospital have demonstrated that patients and caregivers do not understand the critical aspect of thermosensitive drugs. This observation has led to the development of tools designed to secure the cold chain for thermosensitive drugs and to increase awareness among healthcare professionals. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  15. Three-dimensional design and fabrication of reduced graphene oxide/polyaniline composite hydrogel electrodes for high performance electrochemical supercapacitors.

    Science.gov (United States)

    Ates, Murat; El-Kady, Maher; Kaner, Richard B

    2018-04-27

    Graphene/polyaniline composite hydrogels (GH/PANI) were chemically synthesized by in situ polymerization of aniline monomer. Graphene hydrogels were obtained by a hydrothermal method and used in supercapacitors. The graphene/polyaniline composite hydrogel exhibits better electrochemical performance than the pure individual components as determined by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopic measurements. A remarkable specific capacitance (C sp ) of 323.9 F g -1 was measured using CV at a scan rate of 2 mV s -1 at 25 °C. GCD measurements (311.3 F g -1 ) and electrochemical impedance analysis also support these results. The numbers were obtained at extremely high loading masses: 7.14 mg cm -2 for GH and GH/PANI synthesized at 0 °C, and 8.93 mg cm -2 for GH/PANI synthesized at 25 °C. The corresponding areal capacitances are 1.14, 1.75 and 2.78 F cm -2 for GH, and GH/PANI composite hydrogels synthesized at 0 °C and 25 °C, respectively. These values in F cm -2 are 3.80, 5.83 and 9.27 times higher than commercially available activated carbon supercapacitors (∼0.3 F cm -2 for a two electrode system). Moreover, the GH/PANI composite synthesized at 25 °C exhibits excellent stability with 99% initial capacitance retention after 1000 charge/discharge cycles. GH/PANI composites synthesized at 0 °C and 25 °C therefore hold promise for use in supercapacitor device applications.

  16. Three-dimensional design and fabrication of reduced graphene oxide/polyaniline composite hydrogel electrodes for high performance electrochemical supercapacitors

    Science.gov (United States)

    Ates, Murat; El-Kady, Maher; Kaner, Richard B.

    2018-04-01

    Graphene/polyaniline composite hydrogels (GH/PANI) were chemically synthesized by in situ polymerization of aniline monomer. Graphene hydrogels were obtained by a hydrothermal method and used in supercapacitors. The graphene/polyaniline composite hydrogel exhibits better electrochemical performance than the pure individual components as determined by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopic measurements. A remarkable specific capacitance (C sp) of 323.9 F g-1 was measured using CV at a scan rate of 2 mV s-1 at 25 °C. GCD measurements (311.3 F g-1) and electrochemical impedance analysis also support these results. The numbers were obtained at extremely high loading masses: 7.14 mg cm-2 for GH and GH/PANI synthesized at 0 °C, and 8.93 mg cm-2 for GH/PANI synthesized at 25 °C. The corresponding areal capacitances are 1.14, 1.75 and 2.78 F cm-2 for GH, and GH/PANI composite hydrogels synthesized at 0 °C and 25 °C, respectively. These values in F cm-2 are 3.80, 5.83 and 9.27 times higher than commercially available activated carbon supercapacitors (˜0.3 F cm-2 for a two electrode system). Moreover, the GH/PANI composite synthesized at 25 °C exhibits excellent stability with 99% initial capacitance retention after 1000 charge/discharge cycles. GH/PANI composites synthesized at 0 °C and 25 °C therefore hold promise for use in supercapacitor device applications.

  17. [On the preparation and mechanical properties of PVA hydrogel bionic cartilage/bone composite artificial articular implants].

    Science.gov (United States)

    Meng, Haoye; Zheng, Yudong; Huang, Xiaoshan; Yue, Bingqing; Xu, Hong; Wang, Yingjun; Chen, Xiaofeng

    2010-10-01

    In view of the problems that conventional artificial cartilages have no bioactivity and are prone to peel off in repeated uses as a result of insufficient strength to bond with subchondral bone, we have designed and prepared a novel kind of PVA-BG composite hydrogel as bionic artificial articular cartilage/bone composite implants. The effects of processes and conditions of preparation on the mechanical properties of implant were explored. In addition, the relationships between compression strain rate, BG content, PVA hydrogels thickness and compressive tangent modulus were also explicated. We also analyzed the effects of cancellous bone aperture, BG and PVA content on the shear strength of bonding interface of artificial articular cartilage with cancellous bone. Meanwhile, the bonding interface of artificial articular cartilage and cancellous bone was characterized by scanning electron microscopy. It was revealed that the compressive modulus of composite implants was correspondingly increased with the adding of BG content and the augments of PVA hydrogel thickness. The compressive modulus and bonding interface were both related to the apertures of cancellous bone. The compressive modulus of composite implants was 1.6-2.23 MPa and the shear strength of bonding interface was 0.63-1.21 MPa. These results demonstrated that the connection between artificial articular cartilage and cancellous bone was adequately firm.

  18. Fabricating continuous electroconductive polyacrylonitrile fibers with thermosensitive property via wet-spinning

    Science.gov (United States)

    Liu, Wanwan; Jin, Yang; Wang, Yangyi; Ge, Mingqiao; Gao, Qiang

    2017-12-01

    In this work, conductive polyacrylonitrile (PAN) composite fiber with thermosensitive property was successfully prepared via wet-spinning. Thermochromic pigment (TCP) microsphere capsules were applied to manufacture color-changing fibers. Meanwhile, light-colored conductive whiskers (ATO@TiO2) were employed to endow polyacrylonitrile fibers with conductivity without prejudicing their thermosensitive property. Interestingly, unlike other conductive fibers in dark color, this kind of conductive composite fiber can be dyed by thermosensitive pigment. The obtained composite fiber containing 20 vol% ATO@TiO2 whiskers shows a resistivity of 105 Ω · cm and could generate heat by Joule heating when being applied under a certain voltage. The composite fiber shows a red color at room temperature, while the color of the composite fiber fades gradually and finally becomes white as temperature rise. This simple and cost-effective approach is expected to inspire more research into the applications of multifunctional conductive fibers.

  19. Reductively Responsive Hydrogel Nanoparticles with Uniform Size, Shape, and Tunable Composition for Systemic siRNA Delivery in Vivo.

    Science.gov (United States)

    Ma, Da; Tian, Shaomin; Baryza, Jeremy; Luft, J Christopher; DeSimone, Joseph M

    2015-10-05

    To achieve the great potential of siRNA based gene therapy, safe and efficient systemic delivery in vivo is essential. Here we report reductively responsive hydrogel nanoparticles with highly uniform size and shape for systemic siRNA delivery in vivo. "Blank" hydrogel nanoparticles with high aspect ratio were prepared using continuous particle fabrication based on PRINT (particle replication in nonwetting templates). Subsequently, siRNA was conjugated to "blank" nanoparticles via a disulfide linker with a high loading ratio of up to 18 wt %, followed by surface modification to enhance transfection. This fabrication process could be easily scaled up to prepare large quantity of hydrogel nanoparticles. By controlling hydrogel composition, surface modification, and siRNA loading ratio, siRNA conjugated nanoparticles were highly tunable to achieve high transfection efficiency in vitro. FVII-siRNA conjugated nanoparticles were further stabilized with surface coating for in vivo siRNA delivery to liver hepatocytes, and successful gene silencing was demonstrated at both mRNA and protein levels.

  20. Property-based design: optimization and characterization of polyvinyl alcohol (PVA) hydrogel and PVA-matrix composite for artificial cornea.

    Science.gov (United States)

    Jiang, Hong; Zuo, Yi; Zhang, Li; Li, Jidong; Zhang, Aiming; Li, Yubao; Yang, Xiaochao

    2014-03-01

    Each approach for artificial cornea design is toward the same goal: to develop a material that best mimics the important properties of natural cornea. Accordingly, the selection and optimization of corneal substitute should be based on their physicochemical properties. In this study, three types of polyvinyl alcohol (PVA) hydrogels with different polymerization degree (PVA1799, PVA2499 and PVA2699) were prepared by freeze-thawing techniques. After characterization in terms of transparency, water content, water contact angle, mechanical property, root-mean-square roughness and protein adsorption behavior, the optimized PVA2499 hydrogel with similar properties of natural cornea was selected as a matrix material for artificial cornea. Based on this, a biomimetic artificial cornea was fabricated with core-and-skirt structure: a transparent PVA hydrogel core, surrounding by a ringed PVA-matrix composite skirt that composed of graphite, Fe-doped nano hydroxyapatite (n-Fe-HA) and PVA hydrogel. Different ratio of graphite/n-Fe-HA can tune the skirt color from dark brown to light brown, which well simulates the iris color of Oriental eyes. Moreover, morphologic and mechanical examination showed that an integrated core-and-skirt artificial cornea was formed from an interpenetrating polymer network, no phase separation appeared on the interface between the core and the skirt.

  1. Genipin Cross-Linked Chitosan-Polyvinylpyrrolidone Hydrogels: Influence of Composition and Postsynthesis Treatment on pH Responsive Behaviour

    Directory of Open Access Journals (Sweden)

    Chinyelumndu Jennifer Nwosu

    2015-01-01

    Full Text Available Understanding the factors that influence the pH responsive behaviour of biocompatible cross-linked hydrogel networks is essential when aiming to synthesise a mechanically stable and yet stimuli responsive material suitable for various applications including drug delivery and tissue engineering. In this study the behaviour of intelligent chitosan-polyvinylpyrrolidone-genipin cross-linked hydrogels is examined as a function of their composition and postsynthesis treatment. Hydrogels are synthesised with varying amounts of each component (chitosan, polyvinylpyrrolidone, and genipin and their response in a pH 2 buffer is measured optically. The influence of postsynthesis treatment on stability and smart characteristics is assessed using selected hydrogel samples synthesised at 30, 40, and 50°C. After synthesis, samples are exposed to either continuous freezing or three freeze-thaw cycles resulting in increased mechanical stability for all samples. Further morphological and mechanical characterisations have aided the understanding of how postsynthesis continual freezing or freeze-thaw manipulation affects network attributes.

  2. Synthesis and Characterization of Injectable Hydrogels with Varying Collagen–Chitosan–Thymosin β4 Composition for Myocardial Infarction Therapy

    Directory of Open Access Journals (Sweden)

    Achmad Dzihan Shaghiera

    2018-04-01

    Full Text Available Thirty percent of global mortalities are caused by cardiovascular disease, and 54% of the aforementioned amount is instigated by ischemic heart disease that triggered myocardial infarction. Myocardial infarction is due to blood flow cessation in certain coronary arteries that causes lack of oxygen (ischemia and stimulates myocardial necrosis. One of the methods to treat myocardial infarction consists in injecting cells or active biomolecules and biomaterials into heart infarction locations. This study aimed to investigate the characteristics of a collagen–chitosan-based hydrogel with variations in its chitosan composition. The prepared hydrogels contained thymosin β4 (Tβ4, a 43-amino acid peptide with angiogenic and cardioprotective properties which can act as a bioactive molecule for the treatment of myocardial infarction. A morphological structure analysis showed that the hydrogels lacked interconnecting pores. All samples were not toxic on the basis of a cytotoxicity test. A histopathological anatomy test showed that the collagen–chitosan–thymosin β4 hydrogels could stimulate angiogenesis and epicardial heart cell migration, as demonstrated by the evaluation of the number of blood vessels and the infiltration extent of myofibroblasts.

  3. Temporally controlled growth factor delivery from a self-assembling peptide hydrogel and electrospun nanofibre composite scaffold.

    Science.gov (United States)

    Bruggeman, Kiara F; Wang, Yi; Maclean, Francesca L; Parish, Clare L; Williams, Richard J; Nisbet, David R

    2017-09-21

    Tissue-specific self-assembling peptide (SAP) hydrogels designed based on biologically relevant peptide sequences have great potential in regenerative medicine. These materials spontaneously form 3D networks of physically assembled nanofibres utilising non-covalent interactions. The nanofibrous structure of SAPs is often compared to that of electrospun scaffolds. These electrospun nanofibers are produced as sheets that can be engineered from a variety of polymers that can be chemically modified to incorporate many molecules including drugs and growth factors. However, their macroscale morphology limits them to wrapping and bandaging applications. Here, for the first time, we combine the benefits of these systems to describe a two-component composite scaffold from these biomaterials, with the design goal of providing a hydrogel scaffold that presents 3D structures, and also has temporal control over drug delivery. Short fibres, cut from electrospun scaffolds, were mixed with our tissue-specific SAP hydrogel to provide a range of nanofibre sizes found in the extracellular matrix (10-300 nm in diameter). The composite material maintained the shear-thinning and void-filling properties of SAP hydrogels that have previously been shown to be effective for minimally invasive material injection, cell delivery and subsequent in vivo integration. Both scaffold components were separately loaded with growth factors, important signaling molecules in tissue regeneration whose rapid degradation limits their clinical efficacy. The two biomaterials provided sequential growth factor delivery profiles: the SAP hydrogel provided a burst release, with the release rate decreasing over 12 hours, while the electrospun nanofibres provided a more constant, sustained delivery. Importantly, this second release commenced 6 days later. The design rules established here to provide temporally distinct release profiles can enable researchers to target specific stages in regeneration, such as the

  4. 3D Printing and Electrospinning of Composite Hydrogels for Cartilage and Bone Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Arianna De Mori

    2018-03-01

    Full Text Available Injuries of bone and cartilage constitute important health issues costing the National Health Service billions of pounds annually, in the UK only. Moreover, these damages can become cause of disability and loss of function for the patients with associated social costs and diminished quality of life. The biomechanical properties of these two tissues are massively different from each other and they are not uniform within the same tissue due to the specific anatomic location and function. In this perspective, tissue engineering (TE has emerged as a promising approach to address the complexities associated with bone and cartilage regeneration. Tissue engineering aims at developing temporary three-dimensional multicomponent constructs to promote the natural healing process. Biomaterials, such as hydrogels, are currently extensively studied for their ability to reproduce both the ideal 3D extracellular environment for tissue growth and to have adequate mechanical properties for load bearing. This review will focus on the use of two manufacturing techniques, namely electrospinning and 3D printing, that present promise in the fabrication of complex composite gels for cartilage and bone tissue engineering applications.

  5. Hydrogels 2.0: improved properties with nanomaterial composites for biomedical applications

    International Nuclear Information System (INIS)

    Memic, Adnan; Aldhahri, Musab; Alhadrami, Hani A; Hussain, M Asif; Al Nowaiser, Fozia; Al-Hazmi, Faten; Oklu, Rahmi; Khademhosseini, Ali

    2016-01-01

    The incorporation of nanomaterials in hydrogels (hydrated networks of crosslinked polymers) has emerged as a useful method for generating biomaterials with tailored functionality. With the available engineering approaches it is becoming much easier to fabricate nanocomposite hydrogels that display improved performance across an array of electrical, mechanical, and biological properties. In this review, we discuss the fundamental aspects of these materials as well as recent developments that have enabled their application. Specifically, we highlight synthesis and fabrication, and the choice of nanomaterials for multifunctionality as ways to overcome current material property limitations. In addition, we review the use of nanocomposite hydrogels within the framework of biomedical and pharmaceutical disciplines. (paper)

  6. Highly Elastic, Transparent, and Conductive 3D-Printed Ionic Composite Hydrogels

    KAUST Repository

    Odent, Jé ré my; Wallin, Thomas J.; Pan, Wenyang; Kruemplestaedter, Kevin; Shepherd, Robert F.; Giannelis, Emmanuel P.

    2017-01-01

    Despite extensive progress to engineer hydrogels for a broad range of technologies, practical applications have remained elusive due to their (until recently) poor mechanical properties and lack of fabrication approaches, which constrain active

  7. Thermo-and pH-sensitive hydrogel membranes composed of poly(N-isopropylacrylamide)-hyaluronan for biomedical applications: Influence of hyaluronan incorporation on the membrane properties.

    Science.gov (United States)

    Kamoun, Elbadawy A; Fahmy, Alaa; Taha, Tarek H; El-Fakharany, Esmail M; Makram, Mohamed; Soliman, Hesham M A; Shehata, Hassan

    2018-01-01

    Interpenetrating hydrogel membranes consisting of pH-sensitive hyaluronan (HA) and thermo-sensitive poly(N-isopropylacrylamide) (PNIPAAM) were synthesized using redox polymerization, followed by N,N-methylenebisacrylamide (BIS) and epichlorohydrin (EPI) were added as chemical crosslinkers. The interaction between membrane compositions has been characterized by FTIR spectroscopy and discussed intensively. The result indicates that HA incorporation in membranes increase the gel fraction, swelling uptake, and the flexibility/elasticity of crosslinked membranes, however it reduced oppositely the mechanical elongation of membranes. PNIPAAm-HA hydrogels responded to both temperature and pH changes and the stimuli-responsiveness was reversible. However, in vitro bioevaluation results revealed that the released ampicillin during the burst release time was sharply influenced and increased with increasing HA contents in membranes; afterwards it became sustainable. Whereas, high HA contents in hydrogels unexpectedly impacted negatively on the cells viability, owing to the viscosity of cell culture media changed. A big resistance was observed against microbial growth of Staphylococcus aureus, Salmonella typhi, and Candida albicans in case of pure PNIPAAm hydrogel membranes without HA or ampicillin. However, HA incorporation or the loaded ampicillin in membranes showed unexpected easily microbial growth. The fast release performance with dual pH-thermo-sensitive hydrogels were suggested as promising materials for quick drug carrier in the biomedical field. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Preparation of thermo-sensitive slow releasing material and its application in low tar tobacco

    Directory of Open Access Journals (Sweden)

    Tian Zhong

    2017-04-01

    Full Text Available To solve some sensory defects such as fragrance deficiency,strong dry sense,poor satisfaction in the development of ultra-low tar tobacco products,we prepared a new thermo sensitive slow releasing composite material with tobacco aroma.The characterization results showed that the as-prepared thermosensitive particles have better aroma enhancing and slow releasing effects.Also,the aroma components of the tip stick containing thermosensitive particles were detected and its sensory quality was evaluated.The results showed that composite tip stick could enhance the aroma and improve the sensory quality of the cigarettes.

  9. Biphasic Equilibrium Dialysis of Poly(N-Isopropyl Acrylamide Nanogels Synthesized at Decreased Temperatures for Targeted Delivery of Thermosensitive Bioactives

    Directory of Open Access Journals (Sweden)

    Witold Musial

    2013-01-01

    Full Text Available Hydrogel nanoparticles, referred to also as nanogels, are of special interest for medical and pharmaceutical applications. Due to small size in the range below the diameter of the capillaries, they are proposed as drug delivery carriers. The aim of the study was to estimate the influence of composition and reaction conditions during synthesis of poly-N-isopropyl acrylamide cross-linked by polyethylene glycol diacrylate on the purification rates of the polymer. Six types of thermosensitive nanogels were prepared by surfactant-free dispersion polymerization and assessed in terms of process yield, composition, and size at temperatures below and over volume phase temperature. During the diffusion of impurities, in the course of dialysis, assessed by the conductometric method, the remarkable influence of temperature and initiator concentration on the process was revealed. The release rates varied in the range between 9.63 · 10−2 and 1.39 · 10−1 h−1 in the first stage of the process, whereas in the second stage they were between 2.09 · 10−2 and 6.28 · 10−2 h−1. The evaluated time to obtain acceptable purity of the preparation was estimated to be in the range of 18 days. More detailed research should be directed towards the influence of the structure of obtained material on the purification process.

  10. Novel injectable gellan gum hydrogel composites incorporating Zn- and Sr-enriched bioactive glass microparticles: High-resolution X-ray microcomputed tomography, antibacterial and in vitro testing.

    Science.gov (United States)

    Douglas, Timothy E L; Dziadek, Michal; Gorodzha, Svetlana; Lišková, Jana; Brackman, Gilles; Vanhoorne, Valérie; Vervaet, Chris; Balcaen, Lieve; Del Rosario Florez Garcia, Maria; Boccaccini, Aldo R; Weinhardt, Venera; Baumbach, Tilo; Vanhaecke, Frank; Coenye, Tom; Bačáková, Lucie; Surmeneva, Maria A; Surmenev, Roman A; Cholewa-Kowalska, Katarzyna; Skirtach, Andre G

    2018-06-01

    Mineralization of hydrogel biomaterials is desirable to improve their suitability as materials for bone regeneration. In this study, gellan gum (GG) hydrogels were formed by simple mixing of GG solution with bioactive glass microparticles of 45S5 composition, leading to hydrogel formation by ion release from the amorphous bioactive glass microparticles. This resulted in novel injectable, self-gelling composites of GG hydrogels containing 20% bioactive glass. Gelation occurred within 20 min. Composites containing the standard 45S5 bioactive glass preparation were markedly less stiff. X-ray microcomputed tomography proved to be a highly sensitive technique capable of detecting microparticles of diameter approximately 8 μm, that is, individual microparticles, and accurately visualizing the size distribution of bioactive glass microparticles and their aggregates, and their distribution in GG hydrogels. The widely used melt-derived 45S5 preparation served as a standard and was compared with a calcium-rich, sol-gel derived preparation (A2), as well as A2 enriched with zinc (A2Zn5) and strontium (A2Sr5). A2, A2Zn, and A2Sr bioactive glass particles were more homogeneously dispersed in GG hydrogels than 45S5. Composites containing all four bioactive glass preparations exhibited antibacterial activity against methicillin-resistant Staphylococcus aureus. Composites containing A2Zn5 and A2Sr5 bioactive glasses supported the adhesion and growth of osteoblast-like cells and were considerably more cytocompatible than 45S5. All composites underwent mineralization with calcium-deficient hydroxyapatite upon incubation in simulated body fluid. The extent of mineralization appeared to be greatest for composites containing A2Zn5 and 45S5. The results underline the importance of the choice of bioactive glass when preparing injectable, self-gelling composites. Copyright © 2018 John Wiley & Sons, Ltd.

  11. In situ synthesis of bilayered gradient poly(vinyl alcohol)/hydroxyapatite composite hydrogel by directional freezing-thawing and electrophoresis method.

    Science.gov (United States)

    Su, Cui; Su, Yunlan; Li, Zhiyong; Haq, Muhammad Abdul; Zhou, Yong; Wang, Dujin

    2017-08-01

    Bilayered poly(vinyl alcohol) (PVA)/hydroxyapatite (HA) composite hydrogels with anisotropic and gradient mechanical properties were prepared by the combination of directional freezing-thawing (DFT) and electrophoresis method. Firstly, PVA hydrogels with aligned channel structure were prepared by the DFT method. Then, HA nanoparticles were in situ synthesized within the PVA hydrogels via electrophoresis. By controlling the time of the electrophoresis process, a bilayered gradient hydrogel containing HA particles in only half of the gel region was obtained. The PVA/HA composite hydrogel exhibited gradient mechanical strength depending on the distance to the cathode. The gradient initial tensile modulus ranging from 0.18MPa to 0.27MPa and the gradient initial compressive modulus from 0.33MPa to 0.51MPa were achieved. The binding strength of the two regions was relatively high and no apparent internal stress or defect was observed at the boundary. The two regions of the bilayered hydrogel also showed different osteoblast cell adhesion properties. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Collagen immobilized PVA hydrogel-hydroxyapatite composites prepared by kneading methods as a material for peripheral cuff of artificial cornea

    International Nuclear Information System (INIS)

    Kobayashi, Hisatoshi; Kato, Masabumi; Taguchi, Tetsushi; Ikoma, Toshiyuki; Miyashita, Hideyuki; Shimmura, Shigeto; Tsubota, Kazuo; Tanaka, Junzo

    2004-01-01

    In order to achieve the firm fixation of the artificial cornea to host tissues, composites of collagen-immobilized poly(vinyl alcohol) hydrogel with hydroxyapatite were synthesized by a hydroxyapatite particles kneading method. The preparation method, characterization, and the results of corneal cell adhesion and proliferation on the composite material were studied. PVA-COL-HAp composites were successfully synthesized. A micro-porous structure of the PVA-COL-HAp could be introduced by hydrochloric acid treatment and the porosity could be controlled by the pH of the hydrochloric acid solution, the treatment time, and the crystallinity of the HAp particles. Chick embryonic keratocyto-like cells were well attached and proliferated on the PVA-COL-HAp composites. This material showed potential for keratoprosthesis application. Further study such as a long-term animal study is now required

  13. Thermo-sensitive intelligent track membrane

    International Nuclear Information System (INIS)

    Pang Deling; Ren Lihua; Qian Zhilin; Huang Gang; Zhang Jinhua

    1999-01-01

    Using N-isopropylacryl-amide (NIP AAm) thermo-sensitive function material as monomer and nuclear track microporous membrane (NTMM) as baseline material, a thermo-sensitive intelligent track membrane (TsITM) has been prepared by the over-oxidization and pre-irradiation grafting techniques. The TsITM can be used to make a micro-switch controlled by temperature and to adjust particle screening and osmosis. To obtain sub-micron responsive grafted track pores only a very thin thermo-sensitive layer is needed. The TsITM pores are capable of swelling and shrinking rapidly and respond more sensitively to temperature

  14. Injectable alginate-O-carboxymethyl chitosan/nano fibrin composite hydrogels for adipose tissue engineering.

    Science.gov (United States)

    Jaikumar, Dhanya; Sajesh, K M; Soumya, S; Nimal, T R; Chennazhi, K P; Nair, Shantikumar V; Jayakumar, R

    2015-03-01

    Injectable, biodegradable scaffolds are required for soft tissue reconstruction owing to its minimally invasive approach. Such a scaffold can mimic the native extracellular matrix (ECM), provide uniform distribution of cells and overcome limitations like donor site morbidity, volume loss, etc. So, here we report two classes of biocompatible and biodegradable hydrogel blend systems namely, Alginate/O-carboxymethyl chitosan (O-CMC) and Alginate/poly (vinyl alcohol) (PVA) with the inclusion of fibrin nanoparticles in each. The hydrogels were prepared by ionic cross-linking method. The developed hydrogels were compared in terms of its swelling ratio, degradation profile, compressive strength and elastic moduli. From these preliminary findings, it was concluded that Alginate/O-CMC formed a better blend for tissue engineering applications. The potential of the formed hydrogel as an injectable scaffold was revealed by the survival of adipose derived stem cells (ADSCs) on the scaffold by its adhesion, proliferation and differentiation into adipocytes. Cell differentiation studies of fibrin incorporated hydrogel scaffolds showed better differentiation was confirmed by Oil Red O staining technique. These injectable gels have potential in soft tissue regeneration. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Friction Properties of Laminated Composite Materials of Alpha-Tricalcium Phosphate–Filled Poly (Vinyl Alcohol) Hydrogels

    OpenAIRE

    Yamamoto, Kanae; Iwai, Tomoaki; Shoukaku, Yutaka

    2015-01-01

    The aim of this study was to examine the mechanical characteristics of a polyvinyl alcohol hydrogel (PVA-H) as a candidate material for artificial joint cartilage. In the study, PVA-H was filled with α-tricalcium phosphate (α-TCP) in order to improve its mechanical properties. In addition, laminated composite materials with 3 layers were prepared by laminating α-TCP–filled PVA-H and unfilled PVA-H. The samples were prepared with different numbers of repeated freeze–thaw cycles and several con...

  16. Gradient nano-engineered in situ forming composite hydrogel for osteochondral regeneration.

    Science.gov (United States)

    Radhakrishnan, Janani; Manigandan, Amrutha; Chinnaswamy, Prabu; Subramanian, Anuradha; Sethuraman, Swaminathan

    2018-04-01

    Fabrication of anisotropic osteochondral-mimetic scaffold with mineralized subchondral zone and gradient interface remains challenging. We have developed an injectable semi-interpenetrating network hydrogel construct with chondroitin sulfate nanoparticles (ChS-NPs) and nanohydroxyapatite (nHA) (∼30-90 nm) in chondral and subchondral hydrogel zones respectively. Mineralized subchondral hydrogel exhibited significantly higher osteoblast proliferation and alkaline phosphatase activity (p gradient interface of nHA and ChS-NPs. Microcomputed tomography (μCT) demonstrated nHA gradation while rheology showed predominant elastic modulus (∼930 Pa) at the interface. Co-culture of osteoblasts and chondrocytes in gradient hydrogels showed layer-specific retention of cells and cell-cell interaction at the interface. In vivo osteochondral regeneration by biphasic (nHA or ChS) and gradient (nHA + ChS) hydrogels was compared with control using rabbit osteochondral defect after 3 and 8 weeks. Complete closure of defect was observed in gradient (8 weeks) while defect remained in other groups. Histology demonstrated collagen and glycosaminoglycan deposition in neo-matrix and presence of hyaline cartilage-characteristic matrix, chondrocytes and osteoblasts. μCT showed mineralized neo-tissue formation, which was confined within the defect with higher bone mineral density in gradient (chondral: 0.42 ± 0.07 g/cc, osteal: 0.64 ± 0.08 g/cc) group. Further, biomechanical push-out studies showed significantly higher load for gradient group (378 ± 56 N) compared to others. Thus, the developed nano-engineered gradient hydrogel enhanced hyaline cartilage regeneration with subchondral bone formation and lateral host-tissue integration. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Steady electrodiffusion in hydrogel-colloid composites: macroscale properties from microscale electrokinetics

    Directory of Open Access Journals (Sweden)

    Reghan J. Hill

    2010-03-01

    Full Text Available A rigorous microscale electrokinetic model for hydrogel-colloid composites is adopted to compute macroscale profiles of electrolyte concentration, electrostatic potential, and hydrostatic pressure across membranes that separate electrolytes with different concentrations. The membranes are uncharged polymeric hydrogels in which charged spherical colloidal particles are immobilized and randomly dispersed with a low solid volume fraction. Bulk membrane characteristics and performance are calculated from a continuum microscale electrokinetic model (Hill 2006b, c. The computations undertaken in this paper quantify the streaming and membrane potentials. For the membrane potential, increasing the volume fraction of negatively charged inclusions decreases the differential electrostatic potential across the membrane under conditions where there is zero convective flow and zero electrical current. With low electrolyte concentration and highly charged nanoparticles, the membrane potential is very sensitive to the particle volume fraction. Accordingly, the membrane potential - and changes brought about by the inclusion size, charge and concentration - could be a useful experimental diagnostic to complement more recent applications of the microscale electrokinetic model for electrical microrheology and electroacoustics (Hill and Ostoja-Starzewski 2008, Wang and Hill 2008.Um modelo eletrocinético rigoroso para compósitos formados por um hidrogel e um colóide é adotado para computar os perfis macroscópicos de concentração eletrolítica, potencial eletrostático e pressão hidrostática através de uma membrana que separa soluções com diferentes concentrações eletrolíticas. A membrana é composta por um hidrogel polimérico sem carga elétrica onde partículas esféricas são imobilizadas e dispersas aleatoriamente com baixa fração de volume do sólido. As características da membrana e a sua performance são calculadas a partir de um modelo

  18. A pH-Sensitive Injectable Nanoparticle Composite Hydrogel for Anticancer Drug Delivery

    Directory of Open Access Journals (Sweden)

    Yuanfeng Ye

    2016-01-01

    Full Text Available According to previous reports, low pH-triggered nanoparticles were considered to be excellent carriers for anticancer drug delivery, for the reason that they could trigger encapsulated drug release at mild acid environment of tumor. Herein, an acid-sensitive β-cyclodextrin derivative, namely, acetalated-β-cyclodextrin (Ac-β-CD, was synthesized by acetonation and fabricated to nanoparticles through single oil-in-water (o/w emulsion technique. At the same time, camptothecin (CPT, a hydrophobic anticancer drug, was encapsulated into Ac-β-CD nanoparticles in the process of nanoparticle fabrication. Formed nanoparticles exhibited nearly spherical structure with diameter of 209±40 nm. The drug release behavior of nanoparticles displayed pH dependent changes due to hydrolysis of Ac-β-CD. In order to overcome the disadvantages of nanoparticle and broaden its application, injectable hydrogels with Ac-β-CD nanoparticles were designed and prepared by simple mixture of nanoparticles solution and graphene oxide (GO solution in this work. The injectable property was confirmed by short gelation time and good mobility of two precursors. Hydrogels were characterized by dynamic mechanical test and SEM, which also reflected some structural features. Moreover, all hydrogels underwent a reversible sol-gel transition in alkaline environment. Finally, the results of in vitro drug release profile indicated that hydrogel could control drug release or bind drug inside depending on the pH value of released medium.

  19. The osteoinductive potential of printable, cell-laden hydrogel-ceramic composites.

    NARCIS (Netherlands)

    Fedorovich, N.E.; Leeuwenburgh, S.C.G.; Helm, Y.J. van der; Alblas, J.; Dhert, W.J.

    2012-01-01

    Hydrogels used as injectables or in organ printing often lack the appropriate stimuli to direct osteogenic differentiation of embedded multipotent stromal cells (MSCs), resulting in limited bone formation in these matrices. Addition of calcium phosphate (CaP) particles to the printing mixture is

  20. Fabrication of Chitin/Poly(butylene succinate/Chondroitin Sulfate Nanoparticles Ternary Composite Hydrogel Scaffold for Skin Tissue Engineering

    Directory of Open Access Journals (Sweden)

    S. Deepthi

    2014-12-01

    Full Text Available Skin loss is one of the oldest and still not totally resolved problems in the medical field. Since spontaneous healing of the dermal defects would not occur, the regeneration of full thickness of skin requires skin substitutes. Tissue engineering constructs would provide a three dimensional matrix for the reconstruction of skin tissue and the repair of damage. The aim of the present work is to develop a chitin based scaffold, by blending it with poly(butylene succinate (PBS, an aliphatic, biodegradable and biocompatible synthetic polymer with excellent mechanical properties. The presence of chondroitin sulfate nanoparticles (CSnp in the scaffold would favor cell adhesion. A chitin/PBS/CSnp composite hydrogel scaffold was developed and characterized by SEM (Scanning Electron Microscope, FTIR (Fourier Transform Infrared Spectroscopy, and swelling ratio of scaffolds were analyzed. The scaffolds were evaluated for the suitability for skin tissue engineering application by cytotoxicity, cell attachment, and cell proliferation studies using human dermal fibroblasts (HDF. The cytotoxicity and cell proliferation studies using HDF confirm the suitability of the scaffold for skin regeneration. In short, these results show promising applicability of the developed chitin/PBS/CSnps ternary composite hydrogel scaffolds for skin tissue regeneration.

  1. Synthesis and characterization of cloisite-30B clay dispersed poly (acryl amide/sodium alginate)/AgNp hydrogel composites for the study of BSA protein drug delivery and antibacterial activity

    Science.gov (United States)

    Nanjunda Reddy, B. H.; Ranjan Rauta, Pradipta; Venkatalakshimi, V.; Sreenivasa, Swamy

    2018-02-01

    The aim of this research is to inspect the effect of Cloisite-30B (C30B) modified clay dispersed poly (acrylamide-co-Sodiumalginate)/AgNp hydrogel nanocomposites (PASA/C30B/Ag) for drug delivery and antibacterial activity. A novel hydrogel composite based sodium alginate (SA) and the inorganic modified clay with silver nano particle (C30B/AgNps)polymer hydrogel composites are synthesized via the graft copolymerization of acrylamide (AAm) in an aqueous medium with methylene bisacrylamide (MBA) as a crosslinking agent and ammonium per sulfate(APS) as an initiator. The UV/Visible spectroscopy of obtained composites is successfully studied, which confirms the occurrence of AgNps in the hydrogel composites. And the swelling capacity and bovine serum albumin (BSA) protein as model drug delivery study for these hydrogel nanocomposites have been carried out. The C30B/Ag filled hydrogel composites exhibit superior water absorbency or swelling capacity compared to pure samples and it is establish that the formulations with clay (C30B) dispersed silver nanocomposite hydrogels show improved and somewhat faster rate of drug delivery than other formulations(pure systems) and SEM and TEM reports suggests that the size of AgNps in the composite hydrogels is in the range of 5-10 nm with shrunken surface and the antibacterial characterizations for gram positive and gram negative bacteria are carried out by using Streptococcus faecalis (S. Faecalis) and Escherichia coli (E.coli) as model bacteria and the hydrogel composites of PASA/C30B/Ag shows exceptional antibacterial activity against both the bacteria as compared to pure hydrogel composites samples.

  2. Composite vascular scaffold combining electrospun fibers and physically-crosslinked hydrogel with copper wire-induced grooves structure.

    Science.gov (United States)

    Liu, Yuanyuan; Jiang, Chen; Li, Shuai; Hu, Qingxi

    2016-08-01

    While the field of tissue engineered vascular grafts has greatly advanced, many inadequacies still exist. Successfully developed scaffolds require mechanical and structural properties that match native vessels and optimal microenvironments that foster cell integration, adhesion and growth. We have developed a small diameter, three-layered composite vascular scaffold which consists of electrospun fibers and physically-crosslinked hydrogel with copper wire-induced grooves by combining the electrospinning and dip-coating methods. Scaffold morphology and mechanics were assessed, quantified and compared to native vessels. Scaffolds were seeded with Human Umbilical Vein Endothelial Cells (HUVECs), cultured in vitro for 3 days and were evaluated for cell viability and morphology. The results showed that composite scaffolds had adjustable mechanical strength and favorable biocompatibility, which is important in the future clinical application of Tissue-engineered vascular grafts (TEVGs). Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Kinetics of thermal dehydration of sol-gel derived MgO-ZrO{sub 2} composite hydrogel

    Energy Technology Data Exchange (ETDEWEB)

    Das, Sudip; Das, Sukhen [Jadavpur Univ., Kolkata (India). Dept. of Physics; Mitra, N.K. [Calcutta Univ., Kolkata (India). Dept. of Chemical Technology

    2013-06-15

    The kinetics of thermal dehydration of mixed hydroxide hydrogels in MgO-ZrO{sub 2} system was studied as a function of composition by following the isothermal heat treatment route. Kinetic parameters were calculated through the application of the Guggenheim equation. The expulsion of both loosely bound water and constitutional OH groups were not continuous processes but proceeded in steps. The applicability of 1st order reaction kinetics for the major portion of the reaction for all compositions suggests that during the dehydroxylation process the dehydration is essentially controlled by the orientation of H{sub 2}O molecules and the mutual interaction of hydroxyl groups. Due to a decrease in the concentration of the reacting species the activation energy was always higher at the final stage of dehydration. (orig.)

  4. A PEGylated platelet free plasma hydrogel based composite scaffold enables stable vascularization and targeted cell delivery for volumetric muscle loss.

    Science.gov (United States)

    Aurora, Amit; Wrice, Nicole; Walters, Thomas J; Christy, Robert J; Natesan, Shanmugasundaram

    2018-01-01

    Extracellular matrix (ECM) scaffolds are being used for the clinical repair of soft tissue injuries. Although improved functional outcomes have been reported, ECM scaffolds show limited tissue specific remodeling response with concomitant deposition of fibrotic tissue. One plausible explanation is the regression of blood vessels which may be limiting the diffusion of oxygen and nutrients across the scaffold. Herein we develop a composite scaffold as a vasculo-inductive platform by integrating PEGylated platelet free plasma (PFP) hydrogel with a muscle derived ECM scaffold (m-ECM). In vitro, adipose derived stem cells (ASCs) seeded onto the composite scaffold differentiated into two distinct morphologies, a tubular network in the hydrogel, and elongated structures along the m-ECM scaffold. The composite scaffold showed a high expression of ITGA5, ITGB1, and FN and a synergistic up-regulation of ang1 and tie-2 transcripts. The in vitro ability of the composite scaffold to provide extracellular milieu for cell adhesion and molecular cues to support vessel formation was investigated in a rodent volumetric muscle loss (VML) model. The composite scaffold delivered with ASCs supported robust and stable vascularization. Additionally, the composite scaffold supported increased localization of ASCs in the defect demonstrating its ability for localized cell delivery. Interestingly, ASCs were observed homing in the injured muscle and around the perivascular space possibly to stabilize the host vasculature. In conclusion, the composite scaffold delivered with ASCs presents a promising approach for scaffold vascularization. The versatile nature of the composite scaffold also makes it easily adaptable for the repair of soft tissue injuries. Decellularized extracellular matrix (ECM) scaffolds when used for soft tissue repair is often accompanied by deposition of fibrotic tissue possibly due to limited scaffold vascularization, which limits the diffusion of oxygen and nutrients

  5. Thermosensitive hydrogels for 3D bioprinting of cartilage constructs

    NARCIS (Netherlands)

    Abbadessa, A.

    2017-01-01

    Tissue engineering (TE) aims to regenerate damaged tissues by the combined use of biomaterials and cells, often in presence of bioactive molecules, such as growth factors. Particularly for tissues with poor regenerative capacity, such as articular cartilage, TE approaches may lead to promising

  6. Exploiting Bisphosphonate-Bioactive-Glass Interactions for the Development of Self-Healing and Bioactive Composite Hydrogels

    NARCIS (Netherlands)

    Diba, M.; An, J.; Schmidt, S.; Hembury, M.; Ossipov, D.; Boccaccini, A.R.; Leeuwenburgh, S.C.G.

    2016-01-01

    Hydrogels are widely recognized as promising candidates for various biomedical applications, such as tissue engineering. Recently, extensive research efforts have been devoted to the improvement of the biological and mechanical performance of hydrogel systems by incorporation of functional groups

  7. Irinotecan-encapsulated double-reverse thermosensitive nanocarrier system for rectal administration.

    Science.gov (United States)

    Din, Fakhar Ud; Choi, Ju Yeon; Kim, Dong Wuk; Mustapha, Omer; Kim, Dong Shik; Thapa, Raj Kumar; Ku, Sae Kwang; Youn, Yu Seok; Oh, Kyung Taek; Yong, Chul Soon; Kim, Jong Oh; Choi, Han-Gon

    2017-11-01

    Intravenously administered for the treatment of rectum cancer, irinotecan produces severe side effects due to very high plasma concentrations. A novel irinotecan-encapsulated double reverse thermosensitive nanocarrier system (DRTN) for rectal administration was developed as an alternative. The DRTN was fabricated by dispersing the thermosensitive irinotecan-encapsulated solid lipid nanoparticles (SLN) in the thermosensitive poloxamer solution. Its gel properties, pharmacokinetics, morphology, anticancer activity and immunohistopathology were assessed after its rectal administration to rats and tumor-bearing mice. In the DRTN, the solid form of the SLN and the liquid form of the poloxamer solution persisted at 25 °C; the former melted to liquid, and the latter altered to gel at 36.5 °C. The DRTN was easily administered to the anus, gelling rapidly and strongly after rectal administration. Compared to the conventional hydrogel and intravenously administered solution, it retarded dissolution and initial plasma concentration. The DRTN gave sustained release and nearly constant plasma concentrations of irinotecan at 1-3 h in rats, resulting in improved anticancer activity. It induced no damage to the rat rectum and no body weight loss in tumor-bearing mice. Thus, this irinotecan-encapsulated DRTN associated with a reduced burst effect, lack of toxicity and excellent antitumor efficacy would be strongly recommended as a rectal pharmaceutical product alternative to commercial intravenous injection in the treatment of rectum and colon cancer.

  8. Generation of an rhBMP-2-loaded beta-tricalcium phosphate/hydrogel composite and evaluation of its efficacy on peri-implant bone formation

    International Nuclear Information System (INIS)

    Lee, Jae Hyup; Baek, Hae-Ri; Lee, Ji-Ho; Ryu, Mi Young; Seo, Jun-Hyuk; Lee, Kyung-Mee

    2014-01-01

    Dental implant insertion on a site with low bone quality or bone defect should be preceded by a bone graft or artificial bone graft insertion to heal the defect. We generated a beta-tricalcium phosphate (β-TCP) and poloxamer 407-based hydrogel composite and penetration of the β-TCP/hydrogel composite into the peri-implant area of bone was evaluated by porous bone block experiments. The maximum penetration depth for porous bone blocks and dense bone blocks were 524 μm and 464 μm, respectively. We report the in-vivo performance of a composite of β-TCP/hydrogel composite as a carrier of recombinant human bone morphogenetic protein (rhBMP-2), implanted into a rabbit tibial defect model. Three holes drilled into each tibia of eight male rabbits were (1) grafted with dental implant fixtures; (2) filled with β-TCP/hydrogel composite (containing 5 μg of rhBMP-2), followed by grafting of the dental implant fixtures. Four weeks later, bone-implant contact ratio and peri-implant bone formation were analyzed by radiography, micro-CT and histology of undecalcified specimens. The micro-CT results showed a significantly higher level of trabecular thickness and new bone and peri-implant new bone formation in the experimental treatment compared to the control treatment. Histomorphometry revealed a significantly higher bone-implant contact ratio and peri-implant bone formation with the experimental treatment. The use of β-TCP/poloxamer 407 hydrogel composite as a carrier of rhBMP-2 significantly promoted new bone formation around the dental implant fixture and it also improved the quality of the new bone formed in the tibial marrow space. (paper)

  9. The type and composition of alginate and hyaluronic-based hydrogels influence the viability of stem cells of the apical papilla.

    Science.gov (United States)

    Lambricht, Laure; De Berdt, Pauline; Vanacker, Julie; Leprince, Julian; Diogenes, Anibal; Goldansaz, Hadi; Bouzin, Caroline; Préat, Véronique; Dupont-Gillain, Christine; des Rieux, Anne

    2014-12-01

    The goal of the present work was to evaluate in vitro and in vivo the influence of various types and compositions of natural hydrogels on the viability and metabolic activity of SCAPs. Two alginate, three hyaluronic-based (Corgel™) hydrogel formulations and Matrigel were characterized for their mechanical, surface and microstructure properties using rheology, X-ray photoelectron spectroscopy and scanning electron microscopy, respectively. A characterized SCAP cell line (RP89 cells) was encapsulated in the different experimental hydrogel formulations. Cells were cultured in vitro, or implanted in cyclosporine treated mice. In vitro cell viability was evaluated using a Live/Dead assay and in vitro cellular metabolic activity was evaluated with a MTS assay. In vivo cell apoptosis was evaluated by a TUNEL test and RP89 cells were identified by human mitochondria immunostaining. Hydrogel composition influenced their mechanical and surface properties, and their microstructure. In vitro cell viability was above 80% after 2 days but decreased significantly after 7 days (60-40%). Viability at day 7 was the highest in Matrigel (70%) and then in Corgel 1.5 (60%). Metabolic activity increased over time in all the hydrogels, excepted in alginate SLM. SCAPs survived after 1 week in vivo with low apoptosis (<1%). The highest number of RP89 cells was found in Corgel 5.5 (140cells/mm(2)). Collectively, these data demonstrate that SCAP viability was directly modulated by hydrogel composition and suggest that a commercially available hyaluronic acid-based formulation might be a suitable delivery vehicle for SCAP-based dental pulp regeneration strategies. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  10. Incorporating simvastatin/poloxamer 407 hydrogel into 3D-printed porous Ti6Al4V scaffolds for the promotion of angiogenesis, osseointegration and bone ingrowth.

    Science.gov (United States)

    Liu, Hao; Li, Wei; Liu, Can; Tan, Jie; Wang, Hong; Hai, Bao; Cai, Hong; Leng, Hui-Jie; Liu, Zhong-Jun; Song, Chun-Li

    2016-10-27

    Three-dimensional porous titanium alloys printed via electron beam melting have low stiffness similar to that of cortical bone and are promising scaffolds for orthopedic applications. However, the bio-inert nature of titanium alloy is poorly compatible with bone ingrowth. We previously observed that simvastatin/poloxamer 407 thermosensitive hydrogel induces endogenous angiogenic/osteogenic growth factors and promotes angiogenesis and osteogenesis, but the mechanical properties of this hydrogel are poor. The purpose of this study was to construct 3D-printed porous titanium scaffolds (pTi scaffolds) filled with simvastatin/hydrogel and evaluate the effects of this composite on osseointegration, bone ingrowth and neovascularization using a tibial defect rabbit model. Four and eight weeks after implantation, the bone volume, bone mineral density, mineral apposition rate, and push-in maximum force of the pTi scaffolds filled with simvastatin/hydrogel were significantly higher than those without simvastatin (p bone and neovascularization (p bone ingrowth.

  11. Obtaining new composite biomaterials by means of mineralization of methacrylate hydrogels using the reaction–diffusion method

    International Nuclear Information System (INIS)

    Ramadan, Yousof; González-Sánchez, M. Isabel; Hawkins, Karl; Rubio-Retama, Jorge; Valero, Edelmira; Perni, Stefano; Prokopovich, Polina; López-Cabarcos, Enrique

    2014-01-01

    The present paper describes the synthesis and characterization of a new polymeric biomaterial mineralized with calcium phosphate using the reaction–diffusion method. The scaffold of this biomaterial was a hydrogel constituted by biocompatible polyethylene glycol methyl ether methacrylate (PEGMEM) and 2-(dimethylamino)ethyl methacrylate (DMAEM), which were cross-linked with N-N’-methylenebisacrylamide (BIS). The cross-linking content of the hydrogels was varied from 0.25% to 15% (w/w). The gels were used as matrix where two reactants (Na 2 HPO 4 and CaCl 2 ) diffused from both ends of the gel and upon encountering produced calcium phosphate crystals that precipitated within the polymer matrix forming bands. The shape of the crystals was tuned by modifying the matrix porosity in such a way that when the polymer matrix was slightly reticulated the diffusion reaction produced round calcium phosphate microcrystals, whilst when the polymer matrix was highly reticulated the reaction yielded flat calcium phosphate crystals. Selected area electron diffraction performed on the nanocrystals that constitute the microcrystals showed that they were formed by Brushite (CaHPO 4 .2H 2 O). This new composite material could be useful in medical and dentistry applications such as bone regeneration, bone repair or tissue engineering. - Highlights: • New polymeric biomaterial mineralized with calcium phosphate using the reaction-diffusion method.-Growing of brushite nanocrystals within a polymeric matrix. • Mineralization by reaction diffusion method controls the crystal growth within gels

  12. Super absorbent hydrogel composites as water retentive in soil; Hidrogeis compositos superabsorventes como retentores de agua no solo

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, Antonio Savio G. [Faculdade de Educacao de Itapipoca, Curso de Quimica, UECE, Itapipoca, Ceara (Brazil); Almeida Neto, Manuel P. [Instituto Federal de Educacao, Ciencia e Tecnologia do RN - IFRN, Caico, RN (Brazil); Bezerra, Maslandia N.; Feitosa, Judith P.A., E-mail: judith@dqoi.ufc.br [Departamento de Quimica Organica e Inorganica, UFC, Fortaleza, Ceara (Brazil)

    2011-07-01

    Super absorbent hydrogels (SAP) were synthesized at room temperature, by the use of potassium persulfate as initiator, N,N'-methylene bis acrylamide (MBA) as crosslinking agent, and N,N,N',N'- tetramethylethylenediamine. Gels at the same conditions were prepared with 10% of minerals (bentonite or dolomite). The materials of bentonite series were obtained from acrylamide followed by hydrolysis with NaOH. The gels of dolomite series were prepared from the two co-monomers (acrylamide and acrylate). All SAPs were characterized by elemental microanalysis, FTIR, x-ray diffraction, SEM, and by swelling measurements in water. An intercalated composite was obtained with bentonite hydrogel. After hydrolysis an exfoliated nanocomposite was formed. The dolomite mineral was dispersed in the polymeric matrix. The swelling degrees of the SAPs with mineral were higher than those gels without it. This degree was 1,000 times the dry gel weight. Taking into account the amount of water needed to the process, the gel with dolomite is the most promising as soil conditioner. (author)

  13. In vitro and in vivo evaluation of microporous chitosan hydrogel/nanofibrin composite bandage for skin tissue regeneration.

    Science.gov (United States)

    Sudheesh Kumar, P T; Raj, N Mincy; Praveen, G; Chennazhi, Krishna Prasad; Nair, Shantikumar V; Jayakumar, R

    2013-02-01

    In this work, we have developed chitosan hydrogel/nanofibrin composite bandages (CFBs) and characterized using Fourier transform-infrared spectroscopy and scanning electron microscopy. The homogeneous distribution of nanofibrin in the prepared chitosan hydrogel matrix was confirmed by phosphotungstic acid-hematoxylin staining. The mechanical strength, swelling, biodegradation, porosity, whole-blood clotting, and platelet activation studies were carried out. In addition, the cell viability, cell attachment, and infiltration of the prepared CFBs were evaluated using human umbilical vein endothelial cells (HUVECs) and human dermal fibroblast (HDF) cells. It was found that the CFBs were microporous, flexible, biodegradable, and showed enhanced blood clotting and platelet activity compared to the one without nanofibrin. The prepared CFBs were capable of absorbing fluid and this was confirmed when immersed in phosphate buffered saline. Cell viability studies on HUVECs and HDF cells proved the nontoxic nature of the CFBs. Cell attachment and infiltration studies showed that the cells were found attached and proliferated on the CFBs. In vivo experiments were carried out in Sprague-Dawley rats and found that the wound healing occurred within 2 weeks when treated with CFBs than compared to the bare wound and wound treated with Kaltostat. The deposition of collagen was found to be more on CFB-treated wounds compared to the control. The above results proved the use of these CFBs as an ideal candidate for skin tissue regeneration and wound healing.

  14. Radiation-induced synthesis and swelling properties of p(2-hydroxyethyl methacrylate/itaconic acid/oligo (ethylene glycol) acrylate) terpolymeric hydrogels

    International Nuclear Information System (INIS)

    Micic, M.; Stamenic, D.; Suljovrujic, E.

    2012-01-01

    Since it is presumed that by incorporation of pH-responsive (IA) and temperature-responsive (OEGA) co-monomers, it is possible to prepare P(HEMA/IA/OEGA) hydrogels with dual (pH and thermo) responsiveness, the main purpose of our study is to investigate the influence of different mole fractions of IA and especially OEGA on the diversity of the swelling properties of the obtained hydrogels. For that reason, a series of terpolymeric hydrogels with different mole ratios of 2-hydroxyethyl methacrylate (HEMA), itaconic acid (IA) and oligo(ethylene glycol) acrylates (OEGA) was synthesised by gamma radiation. The obtained hydrogels were characterised by swelling studies in the wide pH (2.2–9.0) and temperature range (20–70 °C), confirming dual (pH and thermo) responsiveness and a large variation in the swelling capability. It was observed that the equilibrium swelling of P(HEMA/IA/OEGA) hydrogels, for a constant amount of IA, increased progressively with an increase in OEGA share. On the other hand, the dissociation of carboxyl groups from IA occurs at pH>4; therefore, small mole fractions of IA render good pH sensitivity and a large increase in the swelling capacity of these hydrogels at higher pH values. Additional characterisation of structure and properties was conducted by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and mechanical measurements, confirming that the inherent properties of P(HEMA/IA/OEGA) hydrogels can be significantly tuned by variation in their composition. According to all presented, it seems that the obtained hydrogels can be a beneficial synergetic combination for controlled delivery of bioactive molecules such as drugs, peptides, proteins, etc. - Highlights: ► pH- and thermo-sensitive P(HEMA/IA/OEGA) hydrogels were synthesised by γ radiation. ► OEGA units have a large hydrophilic potential. ► Swelling capacity increases with the OEGA content. ► Variation in composition of hydrogels can give

  15. Synthesis and characterization of chitosan-graft-poly(acrylic acid)/rice husk ash hydrogels composites; Sintese e caracterizacao de hidrogeis compositos de cinza da casca de arroz e quitosana enxertada com poli(acido acrilico)

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Francisco H.A. [Universidade Estadual Vale do Acarau - UVA, Sobral, CE (Brazil); Lopes, Gabriel V.; Pereira, Antonio G.B.; Fajardo, Andre R.; Muniz, Edvani C. [Universidade Estadual de Maringa - UEM, PR (Brazil)

    2011-07-01

    According to environmental concerns, super absorbent hydrogel composites were synthesized based on rice husk ash (RHA), an industrial waste, and Chitosan-graft-poly(acrylic acid). The WAXS and FTIR data confirmed the syntheses of hydrogel composites. The effect of crystalline or amorphous RHA on water uptake was investigated. It was found that the RHA in crystalline form induces higher water capacity (W{sub eq}) of composites hydrogels due to the fact that the intra-interactions among silanol groups on RHA make available new sites in the polymer matrix, which could interact to water. (author)

  16. Reversible pH-Sensitive Chitosan-Based Hydrogels. Influence of Dispersion Composition on Rheological Properties and Sustained Drug Delivery

    Directory of Open Access Journals (Sweden)

    Nieves Iglesias

    2018-04-01

    Full Text Available The present work deals with the synthesis of micro-structured biomaterials based on chitosan (CTS for their applications as biocompatible carriers of drugs and bioactive compounds. Twelve dispersions were prepared by means of functional cross-linking with tricarballylic acid (TCA; they were characterized by Fourier transform infrared spectroscopy (FT-IR, modulated temperature differential scanning calorimetry (MTDSC and scanning electron microscopy (SEM, and their rheological properties were studied. To the best of the authors’ knowledge, no study has been carried out on the influence of CTS concentration, degree of cross-linking and drug loading on chitosan hydrogels for drug delivery systems (DDS and is investigated herein for the first time. The influence of dispersion composition (polymer concentration and degree of cross-linking revealed to exert a marked impact on its rheological properties, going from liquid-like to viscoelastic gels. The release profiles of a model drug, diclofenac sodium (DCNa, as well as their relationships with polymer concentration, drug loading and degree of cross-linking were evaluated. Similar to the findings on rheological properties, a wide range of release profiles was encountered. These formulations were found to display a well-controlled drug release strongly dependent on the formulation composition. Cumulative drug release under physiological conditions for 96 h ranged from 8% to 67%. For comparative purpose, Voltaren emulgel® from Novartis Pharmaceuticals was also investigated and the latter was the formulation with the highest cumulative drug release (85%. Some formulations showed similar spreadability values to the commercial hydrogel. The comparative study of three batches confirmed the reproducibility of the method, leading to systems particularly suitable for their use as drug carriers.

  17. Comparison of H2S adsorption by two hydrogel composite (HBC) derived by Empty Fruit Bunch (EFB) biochar and Coal Fly Ash (CFA)

    Science.gov (United States)

    Meri, N. H.; Alias, A. B.; Talib, N.; Rashid, Z. A.; Ghani, W. A. W. A. K.

    2018-03-01

    This study are covered the adsorption performance of two adsorbent Empty Fruit Bunch Hydrogel Biochar Composite (EFB-HBC) and Coal Fly Ash Hydrogel Composite (CFA-HC) on hydrogen sulphide. The EFB biochar were produce by pyrolysed and heated from room temperature to 550˚C at 10˚C/min under the Nitrogen flow. Meanwhile, coal fly ash collected from a power plant located in Selangor, Malaysia. Both of the materials is a waste from different industries and became the precursor to our adsorbents. EFB biochar and coal fly ash has been synthesized to become hydrogel by polymerization process with acrylamide (AAm) as monomer, N,N’-methylene bisacry lamide (MBA) as cross linker and ammonium persulfate (APS) as initiator. In addition, because of the speciality of hydrogel itself, which is has high ability in storing water, the effect of H2O wetness on EFB-HBC and CFA-HC were investigate in adsorption of H2S. EFB-HBC gave a longest breakthrough time and highest adsorption capacity compared with CFA-HC in both condition (dry/wet). The result also indicated that, the increased the bed height, increased the adsorption capacity.

  18. A composite scaffold of MSC affinity peptide-modified demineralized bone matrix particles and chitosan hydrogel for cartilage regeneration

    Science.gov (United States)

    Meng, Qingyang; Man, Zhentao; Dai, Linghui; Huang, Hongjie; Zhang, Xin; Hu, Xiaoqing; Shao, Zhenxing; Zhu, Jingxian; Zhang, Jiying; Fu, Xin; Duan, Xiaoning; Ao, Yingfang

    2015-12-01

    Articular cartilage injury is still a significant challenge because of the poor intrinsic healing potential of cartilage. Stem cell-based tissue engineering is a promising technique for cartilage repair. As cartilage defects are usually irregular in clinical settings, scaffolds with moldability that can fill any shape of cartilage defects and closely integrate with the host cartilage are desirable. In this study, we constructed a composite scaffold combining mesenchymal stem cells (MSCs) E7 affinity peptide-modified demineralized bone matrix (DBM) particles and chitosan (CS) hydrogel for cartilage engineering. This solid-supported composite scaffold exhibited appropriate porosity, which provided a 3D microenvironment that supports cell adhesion and proliferation. Cell proliferation and DNA content analysis indicated that the DBM-E7/CS scaffold promoted better rat bone marrow-derived MSCs (BMMSCs) survival than the CS or DBM/CS groups. Meanwhile, the DBM-E7/CS scaffold increased matrix production and improved chondrogenic differentiation ability of BMMSCs in vitro. Furthermore, after implantation in vivo for four weeks, compared to those in control groups, the regenerated issue in the DBM-E7/CS group exhibited translucent and superior cartilage-like structures, as indicated by gross observation, histological examination, and assessment of matrix staining. Overall, the functional composite scaffold of DBM-E7/CS is a promising option for repairing irregularly shaped cartilage defects.

  19. Amino-functionalized poloxamer 407 with both mucoadhesive and thermosensitive properties: preparation, characterization and application in a vaginal drug delivery system

    Directory of Open Access Journals (Sweden)

    Liqian Ci

    2017-09-01

    Full Text Available Lack of mucoadhesive properties is the major drawback to poloxamer 407 (F127-based in situ hydrogels for mucosal administration. The objective of the present study was to construct a novel mucoadhesive and thermosensitive in situ hydrogel drug delivery system based on an amino-functionalized poloxamer for vaginal administration. First, amino-functionalized poloxamer 407 (F127-NH2 was synthesized and characterized with respect to its micellization behavior and interaction with mucin. Then using acetate gossypol (AG as model drug, AG-loaded F127-NH2-based in situ hydrogels (NFGs were evaluated with respect to rheology, drug release, ex vivo vaginal mucosal adhesion, in vivo intravaginal retention and local irritation after vaginal administration to healthy female mice. The results show that F127-NH2 is capable of forming a thermosensitive in situ hydrogel with sustained drug release properties. An interaction between positively charged F127-NH2 and negatively charged mucin was revealed by changes in the particle size and zeta potential of mucin particles as well as an increase in the complex modulus of NFG caused by mucin. Ex vivo and in vivo fluorescence imaging and quantitative analysis of the amount of AG remaining in mouse vaginal lavage all demonstrated greater intravaginal retention of NFG than that of an unmodified F127-based in situ hydrogel. In conclusion, amino group functionalization confers valuable mucoadhesive properties on poloxamer 407.

  20. Obtaining new composite biomaterials by means of mineralization of methacrylate hydrogels using the reaction–diffusion method

    Energy Technology Data Exchange (ETDEWEB)

    Ramadan, Yousof [Department of Physical Chemistry II, Faculty of Pharmacy, Complutense University of Madrid, 28040 Madrid (Spain); González-Sánchez, M. Isabel [Department of Physical Chemistry, School of Industrial Engineering, Castilla-La Mancha University, 02071 Albacete (Spain); Hawkins, Karl [Centre of Nanohealth, Institute of Life Sciences, College of Medicine, Swansea University, Singleton Park, Swansea SA2 8PP, Wales (United Kingdom); Rubio-Retama, Jorge [Department of Physical Chemistry II, Faculty of Pharmacy, Complutense University of Madrid, 28040 Madrid (Spain); Valero, Edelmira [Department of Physical Chemistry, School of Industrial Engineering, Castilla-La Mancha University, 02071 Albacete (Spain); Perni, Stefano [School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff CF103NB (United Kingdom); Department of Biological Engineering, MA Institute of Technology, Cambridge (United States); Prokopovich, Polina [School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff CF103NB (United Kingdom); Institute of Medical Engineering and Medical Physics, School of Engineering, Cardiff University, Cardiff (United Kingdom); Department of Biological Engineering, MA Institute of Technology, Cambridge (United States); López-Cabarcos, Enrique, E-mail: cabarcos@farm.ucm.es [Department of Physical Chemistry II, Faculty of Pharmacy, Complutense University of Madrid, 28040 Madrid (Spain)

    2014-09-01

    The present paper describes the synthesis and characterization of a new polymeric biomaterial mineralized with calcium phosphate using the reaction–diffusion method. The scaffold of this biomaterial was a hydrogel constituted by biocompatible polyethylene glycol methyl ether methacrylate (PEGMEM) and 2-(dimethylamino)ethyl methacrylate (DMAEM), which were cross-linked with N-N’-methylenebisacrylamide (BIS). The cross-linking content of the hydrogels was varied from 0.25% to 15% (w/w). The gels were used as matrix where two reactants (Na{sub 2}HPO{sub 4} and CaCl{sub 2}) diffused from both ends of the gel and upon encountering produced calcium phosphate crystals that precipitated within the polymer matrix forming bands. The shape of the crystals was tuned by modifying the matrix porosity in such a way that when the polymer matrix was slightly reticulated the diffusion reaction produced round calcium phosphate microcrystals, whilst when the polymer matrix was highly reticulated the reaction yielded flat calcium phosphate crystals. Selected area electron diffraction performed on the nanocrystals that constitute the microcrystals showed that they were formed by Brushite (CaHPO{sub 4}.2H{sub 2}O). This new composite material could be useful in medical and dentistry applications such as bone regeneration, bone repair or tissue engineering. - Highlights: • New polymeric biomaterial mineralized with calcium phosphate using the reaction-diffusion method.-Growing of brushite nanocrystals within a polymeric matrix. • Mineralization by reaction diffusion method controls the crystal growth within gels.

  1. Thermosensitive shutter for radioactive source housing

    International Nuclear Information System (INIS)

    Fullagar, H.

    1986-01-01

    A shutter apparatus for a radioactive source housing comprises a movable member and a thermosensitive releasing means operative normally to hold the movable member in an open position but to release the movable member to move to a position closing the housing to contain the source when the temperature exceeds a predetermined value, for example as a result of fire. (author)

  2. Synthesis of modified gum tragacanth/graphene oxide composite hydrogel for heavy metal ions removal and preparation of silver nanocomposite for antibacterial activity.

    Science.gov (United States)

    Sahraei, Razieh; Ghaemy, Mousa

    2017-02-10

    New composite hydrogels were synthesized based on gum tragacanth (GT) carbohydrate and graphene oxide (GO). GT was sulfonic acid-functionalized and cross-linked by using 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and N,N'-methylenebisacrylamide (MBA) monomers and ceric ammonium nitrate (CAN) as an initiator. The prepared hydrogels were characterized by Fourier transform infrared spectrum (FT-IR), field emission scanning electron microscope (FE-SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Adsorption process for removal of heavy metal ions has followed the pseudo-first-order kinetic model and fitted well with the Langmuir model. The maximum adsorption capacity (Q m ) was 142.50, 112.50 and 132.12mgg -1 for Pb(II), Cd(II), and Ag(I), respectively. The removal percentage decreased slightly after several adsorption/desorption cycles. The adsorbed Ag(I) ions in hydrogel were transformed to Ag 0 nanoparticles (with a narrow distribution and mean size of 13.0nm) by using Achillea millefolium flower extract. The antibacterial performance of the Ag 0 nanocomposite hydrogel was also investigated. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Photodegradable, Photoadaptable Hydrogels via Radical-Mediated Disulfide Fragmentation Reaction.

    Science.gov (United States)

    Fairbanks, Benjamin D; Singh, Samir P; Bowman, Christopher N; Anseth, Kristi S

    2011-04-26

    Various techniques have been adopted to impart a biological responsiveness to synthetic hydrogels for the delivery of therapeutic agents as well as the study and manipulation of biological processes and tissue development. Such techniques and materials include polyelectrolyte gels that swell and deswell with changes in pH, thermosensitive gels that contract at physiological temperatures, and peptide cross-linked hydrogels that degrade upon peptidolysis by cell-secreted enzymes. Herein we report a unique approach to photochemically deform and degrade disulfide cross-linked hydrogels, mitigating the challenges of light attenuation and low quantum yield, permitting the degradation of hydrogels up to 2 mm thick within 120 s at low light intensities (10 mW/cm(2) at 365 nm). Hydrogels were formed by the oxidation of thiol-functionalized 4-armed poly(ethylene glycol) macromolecules. These disulfide cross-linked hydrogels were then swollen in a lithium acylphosphinate photoinitiator solution. Upon exposure to light, photogenerated radicals initiate multiple fragmentation and disulfide exchange reactions, permitting and promoting photodeformation, photowelding, and photodegradation. This novel, but simple, approach to generate photoadaptable hydrogels portends the study of cellular response to mechanically and topographically dynamic substrates as well as novel encapsulations by the welding of solid substrates. The principles and techniques described herein hold implications for more than hydrogel materials but also for photoadaptable polymers more generally.

  4. Tunable thermo-responsive hydrogels: synthesis, structural analysis and drug release studies.

    Science.gov (United States)

    Cirillo, Giuseppe; Spataro, Tania; Curcio, Manuela; Spizzirri, U Gianfranco; Nicoletta, Fiore Pasquale; Picci, Nevio; Iemma, Francesca

    2015-03-01

    Thermo-responsive hydrogel films, synthesized by UV-initiated radical polymerization, are proposed as delivery devices for non-steroidal anti-inflammatory drugs (Diclofenac sodium and Naproxen). N-isopropylacrylamide and N,N'-ethylenebisacrylamide were chosen as thermo-sensitive monomer and crosslinker, respectively. Infrared spectroscopy was used to assess the incorporation of monomers into the network, and the network density of hydrogel films was found to strictly depend on both feed composition and film thickness. Calorimetric analyses showed negative thermo-responsive behaviour with shrinking/swelling transition values in the range 32.8-36.1°C. Equilibrium swelling studies around the LCST allowed the correlation between the structural changes and the temperature variations. The mesh size, indeed, rapidly changed from a collapsed to a swollen state, with beneficial effects in applications such as size-selective permeation or controlled drug delivery, while the crosslinking degree, the film thickness, and the loading method deeply influenced the drug release profiles at 25 and 40°C. The analysis of both 3D-network structure, release kinetics and diffusional constraints at different temperatures was evaluated by mathematical modelling. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Effect of Chemical Washing Pre-treatment of Empty Fruit Bunch (EFB) biochar on Characterization of Hydrogel Biochar composite as Bioadsorbent

    Science.gov (United States)

    Meri, N. H.; Alias, A. B.; Talib, N.; Rashid, Z. A.; Wan, W. A.; Ghani, Ab Karim

    2018-05-01

    Hydrogel biochar composite (HBC) is a recent interest among researchers because of the hydrophilic characteristic which can adsorb chemical fluid and showed a versatile potential as adsorbent in removing hazardous material in wastewater and gas stream. In this study, the effect of chemical washing pre-treatment by using two different type of chemical agent Hydrochloric Acid (HCL) and Hydrogen Peroxide (H2O2) was analysed and investigated. The raw EFB biochar was prepared using microwave assisted pyrolysis under 1000W for 30 min under N2 flow with 150 mL/min. To improve the adsoprtion ability, the EFB biochar has been chemical washed pre-treatment with Hydrochloric Acid (HCl) and Hydrogen Peroxide (H2O2) before polymerization process with acrylamide (AAm) as monomer, N,N’-methylenebisacrylamide (MBA) as crosslinker and ammonium persulfate (APS) as initiator. The characterization has studied by using Fourier transform infrared spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). FTIR result shows that, the formation of Raw EFB to Hydrogel Biochar Composite (Raw EFB > EFB Biochar > Treated Biochars (HCl & H2O2) > Hydrogel Biochar Composite) have changed in functional group. For DSC result it shows that the thermal behaviour of all samples is endothermic process and have high thermal resistance.

  6. A thermo-responsive and photo-polymerizable chondroitin sulfate-based hydrogel for 3D printing applications

    NARCIS (Netherlands)

    Abbadessa, A.; Blokzijl, M. M.; Mouser, V. H. M.; Marica, P.; Malda, J.; Hennink, W. E.; Vermonden, T.

    2016-01-01

    The aim ofthis study was to design a hydrogel system based on methacrylated chondroitin sulfate (CSMA) and a thermo-sensitive poly(N-(2-hydroxypropyl) methacrylamide-mono/dilactate)-polyethylene glycol triblock copolymer (M15P10) as a suitable material for additive manufacturing of scaffolds. CSMA

  7. A thermo-responsive and photo-polymerizable chondroitin sulfate-based hydrogel for 3D printing applications

    NARCIS (Netherlands)

    Abbadessa, A|info:eu-repo/dai/nl/369480376; Blokzijl, M M; Mouser, V H M; Marica, P; Malda, J|info:eu-repo/dai/nl/412461099; Hennink, W E|info:eu-repo/dai/nl/070880409; Vermonden, T|info:eu-repo/dai/nl/275124517

    2016-01-01

    The aim of this study was to design a hydrogel system based on methacrylated chondroitin sulfate (CSMA) and a thermo-sensitive poly(N-(2-hydroxypropyl) methacrylamide-mono/dilactate)-polyethylene glycol triblock copolymer (M15P10) as a suitable material for additive manufacturing of scaffolds. CSMA

  8. Cartilage Repair Using Composites of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells and Hyaluronic Acid Hydrogel in a Minipig Model.

    Science.gov (United States)

    Ha, Chul-Won; Park, Yong-Beom; Chung, Jun-Young; Park, Yong-Geun

    2015-09-01

    The cartilage regeneration potential of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) with a hyaluronic acid (HA) hydrogel composite has shown remarkable results in rat and rabbit models. The purpose of the present study was to confirm the consistent regenerative potential in a pig model using three different cell lines. A full-thickness chondral injury was intentionally created in the trochlear groove of each knee in 6 minipigs. Three weeks later, an osteochondral defect, 5 mm wide by 10 mm deep, was created, followed by an 8-mm-wide and 5-mm-deep reaming. A mixture (1.5 ml) of hUCB-MSCs (0.5×10(7) cells per milliliter) and 4% HA hydrogel composite was then transplanted into the defect on the right knee. Each cell line was used in two minipigs. The osteochondral defect created in the same manner on the left knee was untreated to act as the control. At 12 weeks postoperatively, the pigs were sacrificed, and the degree of subsequent cartilage regeneration was evaluated by gross and histological analysis. The transplanted knee resulted in superior and more complete hyaline cartilage regeneration compared with the control knee. The cellular characteristics (e.g., cellular proliferation and chondrogenic differentiation capacity) of the hUCB-MSCs influenced the degree of cartilage regeneration potential. This evidence of consistent cartilage regeneration using composites of hUCB-MSCs and HA hydrogel in a large animal model could be a stepping stone to a human clinical trial in the future. To date, several studies have investigated the chondrogenic potential of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs); however, the preclinical studies are still limited in numbers with various results. In parallel, in the past several years, the cartilage regeneration potential of hUCB-MSCs with a hyaluronic acid (HA) hydrogel composite have been investigated and remarkable results in rat and rabbit models have been attained. (These

  9. Injectable self-gelling composites for bone tissue engineering based on gellan gum hydrogel enriched with different bioglasses

    International Nuclear Information System (INIS)

    Douglas, Timothy E L; Dubruel, Peter; Piwowarczyk, Wojciech; Pamula, Elzbieta; Dokupil, Agnieszka; Liskova, Jana; Schaubroeck, David; Leeuwenburgh, Sander C G; Cuijpers, Vincent M J I; Vanhaecke, Frank; Brackman, Gilles; Coenye, Tom; Balcaen, Lieve; Detsch, Rainer; Boccaccini, Aldo R; Declercq, Heidi; Cornelissen, Ria; Cholewa-Kowalska, Katarzyna

    2014-01-01

    Hydrogels of biocompatible calcium-crosslinkable polysaccharide gellan gum (GG) were enriched with bioglass particles to enhance (i) mineralization with calcium phosphate (CaP); (ii) antibacterial properties and (iii) growth of bone-forming cells for future bone regeneration applications. Three bioglasses were compared, namely one calcium-rich and one calcium-poor preparation both produced by a sol-gel technique (hereafter referred to as A2 and S2, respectively) and one preparation of composition close to that of the commonly used 45S5 type (hereafter referred to as NBG). Incubation in SBF for 7 d, 14 d and 21 d caused apatite formation in bioglass-containing but not in bioglass-free samples, as confirmed by FTIR, XRD, SEM, ICP-OES, and measurements of dry mass, i.e. mass attributable to polymer and mineral and not water. Mechanical testing revealed an increase in compressive modulus in samples containing S2 and NBG but not A2. Antibacterial testing using biofilm-forming meticillin-resistant staphylococcus aureus (MRSA) showed markedly higher antibacterial activity of samples containing A2 and S2 than samples containing NBG and bioglass-free samples. Cell biological characterization using rat mesenchymal stem cells (rMSCs) revealed a stimulatory effect of NBG on rMSC differentiation. The addition of bioglass thus promotes GG mineralizability and, depending on bioglass type, antibacterial properties and rMSC differentiation. (paper)

  10. Adsorption Properties of PVA/PAA/clay Composite Hydrogel Synthesized by Gamma Radiation and its Application in Removal of Crystal Violet Dye from Its Aqueous Solution

    International Nuclear Information System (INIS)

    Kamal, H.; El-Sayed, A. Hegazy; Mohamed, M.M.; Sabaa, M.W.; El-Dessouky, M.M.

    2014-01-01

    Copolymer hydrogels composed of Poly vinyl alcohol (PVA) and Poly acrylic acid (PAA) were prepared by γ-irradiation in the presence of N,N’ methylene bis acrylamide (MBAM) as crosslinking agent or bentonite clay. The copolymers were characterized by FTIR and SEM. The dye adsorption experiments for Crystal Violet dye (CV) were carried out by using bath procedure. UV-visible absorption spectroscopy was used to determine the adsorption behavior. The effect of different copolymer composition, clay concentration, ph, contact time, adsorbent dose, initial dye concentration, and adsorption temperature were investigated to obtain the best experimental conditions. The adsorption equilibrium was attained after about 24h. of contact time. It was found that the adsorption process was correlated with Freundlich isotherm equation. Kinetic and thermodynamic studies of CV dye onto the prepared hydrogels were also evaluated

  11. Preparation and swelling properties of pH-sensitive composite hydrogel beads based on chitosan-g-poly (acrylic acid)/vermiculite and sodium alginate for diclofenac controlled release.

    Science.gov (United States)

    Wang, Qin; Xie, Xiaoling; Zhang, Xiaowei; Zhang, Junping; Wang, Aiqin

    2010-04-01

    A series of pH-sensitive composite hydrogel beads, chitosan-g-poly (acrylic acid)/vermiculite/sodium alginate (CTS-g-PAA/VMT/SA), was prepared using CTS-g-PAA/VMT composite and SA by Ca(2+) as the crosslinking agent. The structure and morphologies of the developed composite hydrogel beads were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The swelling properties and pH-sensitivity of the beads were investigated. In addition, the drug loading and controlled release behaviors of the beads were also evaluated using diclofenac sodium (DS) as the model drug in stimulated gastric fluids (pH 2.1) and intestinal fluids (pH 6.8). The results indicate that the composite hydrogel beads showed good pH-sensitivity. The release rate of the drug from the composite hydrogel beads is remarkably slowed down, which indicated that incorporating VMT into the composite hydrogel beads can improve the burst release effect of the drug. Copyright 2010 Elsevier B.V. All rights reserved.

  12. Evaluation of 2,4-D removal via activated carbon from pomegranate husk/polymer composite hydrogel: Optimization of process parameters through face centered composite design

    International Nuclear Information System (INIS)

    Taktak, Fulya; Ilbay, Zeynep; Sahin, Selin

    2015-01-01

    A new type of polymer composite hydrogel was prepared by introducing activated carbons from pomegranate husk into poly ((2-dimethylamino) ethyl methacrylate) network. The removal of 2,4-dichlorophenoxyacetic acid (2,4-D) from aqueous solution was studied with respect to pH of the media, initial 2,4-D concentration and activated carbon content into the polymeric network. Face centered composite design (FCCD) through response surface methodology (RSM) was used for designing the experiments as well as for studying the effects of the process parameters. A quadratic model and a two factor interaction design model were developed for the removal of 2,4-D and adsorption capacity, respectively. The optimum pH of the pesticide solution, activated carbon content into the polymeric network and initial concentration of 2,4-D were found as 3, 2.5 wt% and 100mg/L. 63.245% and 68.805 (mg/g) for the removal of 2,4-D and adsorption capacity were obtained by using Simplex optimization method. Furthermore, the surface characteristics of the adsorbent prepared under optimized conditions were examined by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR).

  13. Evaluation of 2,4-D removal via activated carbon from pomegranate husk/polymer composite hydrogel: Optimization of process parameters through face centered composite design

    Energy Technology Data Exchange (ETDEWEB)

    Taktak, Fulya; Ilbay, Zeynep [Usak Univ, Usak (Turkmenistan); Sahin, Selin [Istanbul University, Istanbul (Turkmenistan)

    2015-09-15

    A new type of polymer composite hydrogel was prepared by introducing activated carbons from pomegranate husk into poly ((2-dimethylamino) ethyl methacrylate) network. The removal of 2,4-dichlorophenoxyacetic acid (2,4-D) from aqueous solution was studied with respect to pH of the media, initial 2,4-D concentration and activated carbon content into the polymeric network. Face centered composite design (FCCD) through response surface methodology (RSM) was used for designing the experiments as well as for studying the effects of the process parameters. A quadratic model and a two factor interaction design model were developed for the removal of 2,4-D and adsorption capacity, respectively. The optimum pH of the pesticide solution, activated carbon content into the polymeric network and initial concentration of 2,4-D were found as 3, 2.5 wt% and 100mg/L. 63.245% and 68.805 (mg/g) for the removal of 2,4-D and adsorption capacity were obtained by using Simplex optimization method. Furthermore, the surface characteristics of the adsorbent prepared under optimized conditions were examined by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR).

  14. Significance of Glucose Addition on Chitosan-Glycerophosphate Hydrogel Properties

    Directory of Open Access Journals (Sweden)

    Dian Susanthy

    2016-03-01

    Full Text Available Chitosan-glycerophosphate hydrogel can be used as dental scaffold due to its thermosensitivity, gelation performance at body temperature, suitable acidity for body condition, biocompatibility, and ability to provide good environment for cell proliferation and differentiation. Previous study showed that glucose addition to the chitosan solution before steam sterilization improved its hydrogel mechanical strength. However, the effectiveness of glucose addition was still doubted because glucose might undergo Maillard reaction in that particular condition. The aims of this study are to confirm whether the glucose addition can increase the hydrogel mechanical strength and gelation rate effectively and also to compare their performance to be dental scaffold. This research was performed through several steps, namely preparation of chitosan-glycerophosphate solution, addition of glucose, gelation time test, gel mechanical strength measurement, functional group analysis, and physical properties measurements (pH, viscosity, and pore size. The result showed that glucose addition did not improve the hydrogel mechanical strength and gelation rate, neither when it was added before nor after steam sterilization. Glucose addition before steam sterilization seemed to trigger Maillard reaction or browning effect, while glucose addition after steam sterilization increased the amount of free water molecules in the hydrogel. Chitosan and glycerophosphate interact physically, but interaction between chitosan and glucose seems to occur chemically and followed by the formation of free water molecules. Glucose addition decreases the solution viscosity and hydrogel pore size so the hydrogel performance as dental scaffold is lowered.

  15. Controlled release of bioactive PDGF-AA from a hydrogel/nanoparticle composite.

    Science.gov (United States)

    Elliott Donaghue, Irja; Shoichet, Molly S

    2015-10-01

    Polymer excipients, such as low molar mass poly(ethylene glycol) (PEG), have shown contradictory effects on protein stability when co-encapsulated in polymeric nanoparticles. To gain further insight into these effects, platelet-derived growth factor (PDGF-AA) was encapsulated in polymeric nanoparticles with vs. without PEG. PDGF-AA is a particularly compelling protein, as it has been demonstrated to promote cell survival and induce the oligodendrocyte differentiation of neural stem/progenitor cells (NSPCs) both in vitro and in vivo. Here we show, for the first time, the controlled release of bioactive PDGF-AA from an injectable nanoparticle/hydrogel drug delivery system (DDS). PDGF-AA was encapsulated, with high efficiency, in poly(lactide-co-glycolide) nanoparticles, and its release from the drug delivery system was followed over 21 d. Interestingly, the co-encapsulation of low molecular weight poly(ethylene glycol) increased the PDGF-AA loading but, unexpectedly, accelerated the aggregation of PDGF-AA, resulting in reduced activity and detection by enzyme-linked immunosorbent assay (ELISA). In the absence of PEG, released PDGF-AA remained bioactive as demonstrated with NSPC oligodendrocyte differentiation, similar to positive controls, and significantly different from untreated controls. This work presents a novel delivery method for differentiation factors, such as PDGF-AA, and provides insights into the contradictory effects reported in the literature of excipients, such as PEG, on the loading and release of proteins from polymeric nanoparticles. Previously, the polymer poly(ethylene glycol) (PEG) has been used in many biomaterials applications, from surface coatings to the encapsulation of proteins. In this work, we demonstrate that, unexpectedly, low molecular weight PEG has a deleterious effect on the release of the encapsulated protein platelet-derived growth factor AA (PDGF-AA). We also demonstrate release of bioactive PDGF-AA (in the absence of PEG

  16. Preparation and characterization of nanosized P(NIPAM-MBA) hydrogel particles and adsorption of bovine serum albumin on their surface.

    Science.gov (United States)

    Zhu, Xiaoli; Gu, Xiangling; Zhang, Lina; Kong, Xiang-Zheng

    2012-09-24

    Thermosensitive polymer hydrogel particles with size varying from 480 to 620 nm were prepared through precipitation copolymerization of N-isopropylacrylamide with N,N'-methylenebisacrylamide (MBA) in water with ammonium persulfate as the initiator. Only polymer hydrogels without any coagula were obtained when MBA concentration in the monomer mixture was kept between 2.5 and 10.0 wt%; with increased MBA concentration, the monomer conversion was enhanced, the size of the hydrogels was increased, and their shrinking was lessened when heated from 25°C to 40°C. Bovine serum albumin adsorption on the surface of the hydrogels of different MBA content was measured at different pH levels and under different temperatures. The results demonstrated that the adsorption of the protein on the hydrogels could be controlled by adjusting the pH, the temperature of adsorption, and the crosslinking in the hydrogels. The results were interpreted, and the mechanisms of the polymerization were proposed.

  17. Comparison of chitosan nanoparticles and chitosan hydrogels for vaccine delivery

    DEFF Research Database (Denmark)

    Gordon, Sarah; Saupe, Anne; McBurney, Warren

    2008-01-01

    In this work the potential of chitosan nanoparticles (CNP) and thermosensitive chitosan hydrogels as particulate and sustained release vaccine delivery systems was investigated. CNP and chitosan hydrogels were prepared, loaded with the model protein antigen ovalbumin (OVA) and characterised...... of the release of fluorescently-labelled OVA (FITC-OVA) from CNP and chitosan hydrogels in-vitro showed that approximately 50% of the total protein was released from CNP within a period of ten days; release of antigen from chitosan gel occurred in a more sustained manner, with ... released after 10 days. The slow release from gel formulations may be explained by the strong interactions of the protein with chitosan. While OVA-loaded CNP showed no significant immunogenicity, formulations of OVA in chitosan gel were able to stimulate both cell-mediated and humoral immunity in-vivo....

  18. Three-Dimensional Scaffold Chip with Thermosensitive Coating for Capture and Reversible Release of Individual and Cluster of Circulating Tumor Cells.

    Science.gov (United States)

    Cheng, Shi-Bo; Xie, Min; Chen, Yan; Xiong, Jun; Liu, Ya; Chen, Zhen; Guo, Shan; Shu, Ying; Wang, Ming; Yuan, Bi-Feng; Dong, Wei-Guo; Huang, Wei-Hua

    2017-08-01

    Tumor metastasis is attributed to circulating tumor cells (CTC) or CTC clusters. Many strategies have hitherto been designed to isolate CTCs, but there are few methods that can capture and gently release CTC clusters as efficient as single CTCs. Herein, we developed a three-dimensional (3D) scaffold chip with thermosensitive coating for high-efficiency capture and release of individual and cluster CTCs. The 3D scaffold chip successfully combines the specific recognition and physically obstructed effect of 3D scaffold structure to significantly improve cell clusters capture efficiency. Thermosensitive gelatin hydrogel uniformly coated on the scaffold dissolves at 37 °C quickly, and the captured cells are gently released from chip with high viability. Notably, this platform was applied to isolate CTCs from cancer patients' blood samples. This allows global DNA and RNA methylation analysis of collected single CTC and CTC clusters, indicating the great potential of this platform in cancer diagnosis and downstream analysis at the molecular level.

  19. Polysaccharides as Hydrogel and Bioplastics. Chapter 4

    International Nuclear Information System (INIS)

    Kamaruddin Hashim; Sarada Idris; Norzita Yacob; Maznah Mahmud

    2017-01-01

    The use of radiation technology in producing hydrogel is increasingly popular nowadays. The hydrogel which produce through the radiation method has it own advantages. For example, easy to operate, reduce the cost production and also decrease the harmful chemical usage such as monomer. The cross-linking bonds which has been produced this hydrogel during the irradiation process can be controlled by the radiation dosage even though using the same material and composition.

  20. Studies on radiation synthesis of polyethyleneimine/acrylamide hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Francis, Sanju [ISOMED, Radiation Technology Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai - 400 085 (India); Varshney, Lalit [ISOMED, Radiation Technology Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai - 400 085 (India)]. E-mail: lalitv@magnum.barc.ernet.in; Tirumalesh, K. [Isotope Application Division, Bhabha Atomic Research Centre, Trombay, Mumbai - 400 085 (India)

    2006-07-15

    Polyethyleneimine(PEI)/acrylamide(AAM) hydrogels were synthesized by {gamma}-radiation-induced polymerization/crosslinking of aqueous mixtures containing different ratios of PEI and AAM. The gel percentage and equilibrium degree of swelling (EDS) of the synthesized hydrogels were investigated. The compositions of the hydrogels produced were found to be different from the feed composition. Ion-chromatography technique was used to determine the amount of Pb (II) and Cd (II) absorbed by the hydrogel. The maximum binding capacity of the PEI/AAM hydrogels, for Pb and Cd was found to be 19 and 12.6 mg/g, respectively (at 100 ppm). PEI/AAM hydrogels had better metal uptake efficiency than the pure AAM hydrogel at concentrations less than 50 ppm. Pure PEI was observed to be highly degrading type polymer on exposure to gamma radiation. TGA and FT-IR techniques were used to characterize the prepared hydrogels.

  1. Synthesis and characterization of a thermo-sensitive poly( N-methyl acryloylglycine methyl ester) used as a drug release carrier

    Science.gov (United States)

    Deng, Kui-Lin; Zhong, Hai-Bin; Jiao, Yi-Suo; Fan, Ting; Qiao, Xiao; Zhang, Peng-Fei; Ren, Xiao-Bo

    2010-06-01

    In this article, poly( N-methyl acryloylglycine methyl ester) (PNMAME) was prepared as a novel thermosensitive material with a lower critical solution temperature (LCST) at around 49.5°C. The chemical structures of the monomer NMAME and PNMAME were characterized by 1H NMR and IR measurements. The LCST was investigated systematically as a function of PNMAME concentration, inorganic salt solution and pH value. The results indicated that LCST of PNMAME was obviously dependent on PNMAME concentration and pH. The LCST was increased with a decrease in pH value and PNMAME concentration. To obtain a thermo-sensitive hydrogel with the phase transition temperature close to human body temperature, the copolymerization was conducted between NMAME and N-acryloylglycine ethyl ester (NAGEE). The release behavior of caffeine was evaluated at different temperatures and contents of cross-linkers ( N, N-methylenebis(acrylamide) (NMBA)). The increase of cross-linker content led to a decrease in the release rate of caffeine due to higher crossing density in the hydrogel network. In addition, a faster release of caffeine from the hydrogel with 3% NMBA at 37°C was found in contrast to that at 18°C.

  2. Flocculation of flotation tailings using thermosensitive polymers

    Directory of Open Access Journals (Sweden)

    Bogacz Wojciech

    2017-09-01

    Full Text Available The key feature of thermosensitive polymers is the reversible transition between the hydrophilic and hydrophopic forms depending on the temperature. Although the main research efforts are focused on their application in different kinds of drug delivery systems, this phenomenon also allows one to precisely control the stability of solid-liquid dispersions. In this paper research on the application of poly(N-isopropylacrylamide copolymers in processing of minerals is presented. In the experiments tailings from flotation plant of one of the coal mines of Jastrzębska Spółka Węglowa S.A. (Poland were used. A laser particle sizer Fritsch Analysette 22 was used in order to determine the Particle Size Distribution (PSD. It was proved that there are some substantial issues associated with the application of thermosensitive polymers in industrial practice which may exclude them from the common application. High salinity of suspension altered the value of Lower Critical Solution Temperature (LCST. Moreover, the co-polymers used in research proved to be efficient flocculating agents without any temperature rise. Finally, the dosage needed to achieve steric stabilization of suspension was greatly beyond economic justification.

  3. Injectable self-gelling composites for bone tissue engineering based on gellan gum hydrogel enriched with different bioglasses

    NARCIS (Netherlands)

    Douglas, T.E.; Piwowarczyk, W.; Pamula, E.; Liskova, J.; Schaubroeck, D.; Leeuwenburgh, S.C.; Brackman, G.; Balcaen, L.; Detsch, R.; Declercq, H.; Cholewa-Kowalska, K.; Dokupil, A.; Cuijpers, V.M.; Vanhaecke, F.; Cornelissen, R.; Coenye, T.; Boccaccini, A.R.; Dubruel, P.

    2014-01-01

    Hydrogels of biocompatible calcium-crosslinkable polysaccharide gellan gum (GG) were enriched with bioglass particles to enhance (i) mineralization with calcium phosphate (CaP); (ii) antibacterial properties and (iii) growth of bone-forming cells for future bone regeneration applications. Three

  4. Injectable self-gelling composites for bone tissue engineering based on gellan gum hydrogel enriched with different bioglasses

    Czech Academy of Sciences Publication Activity Database

    Douglas, T.E.L.; Piwowarczyk, W.; Pamula, E.; Lišková, Jana; Schaubroeck, D.; Leeuwenburgh, S. C. G.; Brackman, G.; Balcaen, L.; Detsch, R.; Declercq, H.; Cholewa-Kowalska, K.; Dokupil, A.; Cuijpers, V.M.J.I.; Vanhaecke, F.; Cornelissen, R.; Coenye, T.; Boccaccini, A. R.; Dubruel, P.

    2014-01-01

    Roč. 9, č. 4 (2014), 045014 ISSN 1748-6041 R&D Projects: GA MŠk(CZ) EE2.3.30.0025; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:67985823 Keywords : hydrogel * bone tissue engineering * gellan gum * bioglass Subject RIV: EI - Biotechnology ; Bionics Impact factor: 3.697, year: 2014

  5. Device for simultaneous measurements of the optical and dielectric properties of hydrogels

    International Nuclear Information System (INIS)

    Gómez-Galván, F; Lara-Ceniceros, T; Mercado-Uribe, H

    2012-01-01

    We have designed an experimental device to simultaneously measure the light transmittance and dielectric properties of thermo-sensitive hydrogels. We have used this device to study poly(N-isopropylacrylamide) samples in order to understand the mechanism of water deliverance during the phase transition such hydrogels normally exhibit. We found that the phase transition can be observed dielectrically at low frequencies, when the isothermals obtained during the heating of the samples separate into two groups. The phenomenon occurs due to the increase of ions caused by the dissociation of water molecules released by the polymer, and corresponds to the drop of the optical transmittance

  6. Hydrogel based occlusion systems

    NARCIS (Netherlands)

    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

  7. A versatile characterization of poly(N-isopropylacrylamide-co-N,N'-methylene-bis-acrylamide hydrogels for composition, mechanical strength, and rheology

    Directory of Open Access Journals (Sweden)

    J. Kovacs

    2013-01-01

    Full Text Available Poly(N-isopropylacrylamide-co-N,N'-methylene-bisacrylamide (P(NIPAAm-co-MBA hydrogels were prepared in water using redox initiator. The copolymer composition at high conversion (> 95% was determined indirectly by HPLC (high performance liquid chromatography analysis of the leaching water and directly by solid state 13C CP MAS NMR (cross polarization magic angle spinning nuclear magnetic resonance spectroscopy of the dried gels, and was found to be close to that of the feed. The effect of cross-linker (MBA content in the copolymer was investigated in the concentration range of 1.1–9.1 mol% (R:90–10; R = mol NIPAAm/mol MBA on the rheological behaviour and mechanical strength of the hydrogels. Both storage and loss modulus decreased with decreasing cross-linker content as revealed by dynamic rheometry. Gels R70 and R90 with very low cross-linker content (1.2–1.5 mol% MBA have a very loose network structure, which is significantly different from those with higher cross-linker content manifesting in higher difference in storage modulus. The temperature dependence of the damping factor served the most accurate determination of the volume phase transition temperature, which was not affected by the cross-link density in the investigated range of MBA concentration. Gel R10 with highest cross-linker content (9.1 mol% MBA behaves anomalously due to heterogeneity and the hindered conformation of the side chains of PNIPAAm.

  8. Smart hydrogel functional materials

    CERN Document Server

    Chu, Liang-Yin; Ju, Xiao-Jie

    2014-01-01

    This book systematically introduces smart hydrogel functional materials with the configurations ranging from hydrogels to microgels. It serves as an excellent reference for designing and fabricating artificial smart hydrogel functional materials.

  9. Reinforcement of thermoplastic chitosan hydrogel using chitin whiskers optimized with response surface methodology.

    Science.gov (United States)

    Sun, Guohui; Zhang, Xin; Bao, Zixian; Lang, Xuqian; Zhou, Zhongzheng; Li, Yang; Feng, Chao; Chen, Xiguang

    2018-06-01

    To strengthen the mechanical strength of thermo-sensitive hydroxybutyl chitosan (HBC) hydrogel, chitin whiskers were used as sticker to fabricate reinforced HBC (HBCW) hydrogel by using response surface methodology. Unlike the intrinsic network of HBC hydrogel, HBCW hydrogel showed a laminar shape with firm structure. The preparation condition was optimized by three-factor-three-level Box-Behnken design. The maximum mechanical strength (1011.11 Pa) was achieved at 50 °C, when the concentrations of HBC and chitin whiskers were 5.1 wt% and 2.0 wt%, respectively. The effects of temperature, pH value and NaCl concentration on mechanical strength of HBCW hydrogels were investigated via the oscillatory stress sweeps. The results showed that HBCW hydrogel could reach the maximum stiffness (∼1126 Pa) at 37 °C pH 12.0. Low pH and high salty ions could decrease the stability of hydrogel, while chitin whiskers could increase the stress tolerance and related ruptured strain of HBCW hydrogels. Copyright © 2018. Published by Elsevier Ltd.

  10. A review on polymeric hydrogel membranes for wound dressing applications: PVA-based hydrogel dressings

    Directory of Open Access Journals (Sweden)

    Elbadawy A. Kamoun

    2017-05-01

    Full Text Available This review presents the past and current efforts with a brief description on the featured properties of hydrogel membranes fabricated from biopolymers and synthetic ones for wound dressing applications. Many endeavors have been exerted during past ten years for developing new artificial polymeric membranes, which fulfill the demanded conditions for the treatment of skin wounds. This review mainly focuses on representing specifications of ideal polymeric wound dressing membranes, such as crosslinked hydrogels compatible with wound dressing purposes. But as the hydrogels with single component have low mechanical strength, recent trends have offered composite or hybrid hydrogel membranes to achieve the typical wound dressing requirements.

  11. Enzymatically crosslinked silk-hyaluronic acid hydrogels.

    Science.gov (United States)

    Raia, Nicole R; Partlow, Benjamin P; McGill, Meghan; Kimmerling, Erica Palma; Ghezzi, Chiara E; Kaplan, David L

    2017-07-01

    In this study, silk fibroin and hyaluronic acid (HA) were enzymatically crosslinked to form biocompatible composite hydrogels with tunable mechanical properties similar to that of native tissues. The formation of di-tyrosine crosslinks between silk fibroin proteins via horseradish peroxidase has resulted in a highly elastic hydrogel but exhibits time-dependent stiffening related to silk self-assembly and crystallization. Utilizing the same method of crosslinking, tyramine-substituted HA forms hydrophilic and bioactive hydrogels that tend to have limited mechanics and degrade rapidly. To address the limitations of these singular component scaffolds, HA was covalently crosslinked with silk, forming a composite hydrogel that exhibited both mechanical integrity and hydrophilicity. The composite hydrogels were assessed using unconfined compression and infrared spectroscopy to reveal of the physical properties over time in relation to polymer concentration. In addition, the hydrogels were characterized by enzymatic degradation and for cytotoxicity. Results showed that increasing HA concentration, decreased gelation time, increased degradation rate, and reduced changes that were observed over time in mechanics, water retention, and crystallization. These hydrogel composites provide a biologically relevant system with controllable temporal stiffening and elasticity, thus offering enhanced tunable scaffolds for short or long term applications in tissue engineering. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Nanodiamond-based injectable hydrogel for sustained growth factor release: Preparation, characterization and in vitro analysis.

    Science.gov (United States)

    Pacelli, Settimio; Acosta, Francisca; Chakravarti, Aparna R; Samanta, Saheli G; Whitlow, Jonathan; Modaresi, Saman; Ahmed, Rafeeq P H; Rajasingh, Johnson; Paul, Arghya

    2017-08-01

    Nanodiamonds (NDs) represent an emerging class of carbon nanomaterials that possess favorable physical and chemical properties to be used as multifunctional carriers for a variety of bioactive molecules. Here we report the synthesis and characterization of a new injectable ND-based nanocomposite hydrogel which facilitates a controlled release of therapeutic molecules for regenerative applications. In particular, we have formulated a thermosensitive hydrogel using gelatin, chitosan and NDs that provides a sustained release of exogenous human vascular endothelial growth factor (VEGF) for wound healing applications. Addition of NDs improved the mechanical properties of the injectable hydrogels without affecting its thermosensitive gelation properties. Biocompatibility of the generated hydrogel was verified by in vitro assessment of apoptotic gene expressions and anti-inflammatory interleukin productions. NDs were complexed with VEGF and the inclusion of this complex in the hydrogel network enabled the sustained release of the angiogenic growth factor. These results suggest for the first time that NDs can be used to formulate a biocompatible, thermosensitive and multifunctional hydrogel platform that can function both as a filling agent to modulate hydrogel properties, as well as a delivery platform for the controlled release of bioactive molecules and growth factors. One of the major drawbacks associated with the use of conventional hydrogels as carriers of growth factors is their inability to control the release kinetics of the loaded molecules. In fact, in most cases, a burst release is inevitable leading to diminished therapeutic effects and unsuccessful therapies. As a potential solution to this issue, we hereby propose a strategy of incorporating ND complexes within an injectable hydrogel matrix. The functional groups on the surface of the NDs can establish interactions with the model growth factor VEGF and promote a prolonged release from the polymer network

  13. Preparation and Study on Properties of Superabsorbent Hydrogel Composites of Acrylamide-Acrylic Acid and Zeolite in Agricultural Uses

    Directory of Open Access Journals (Sweden)

    Shohreh Vosuoghi

    2017-11-01

    Full Text Available Water shortage is one of the most important environmental problems in arid and semi-arid areas which cause complications in land vegetations. The use of superabsorbent hydrogel is one of the most vital methods, which helps to optimize agricultural irrigations. The purpose of this research is preparation and study on properties the superabsorbent hydrogels by copolymerization of acrylamide and acrylic acid monomers using zeolite as nanoclay particles (0, 0.05, 0.1, 0.15. The optimum amount of nanoparticles in relation to its effect on superabsorbent structure and properties, such as water absorbency, was investigated through designing experiments using FFD software. We used methylene bisacrylamide and ammonium ‌persulfate as crosslinker and initiator, respectively. Thermogravimetric analysis (TGA, Fourier transform spectroscopy (FTIR, scanning electron microscopy (SEM and X-ray diffractometry (XRD test results showed that the addition of nanoclay up to 0.1g caused improvement in the physical and chemical properties of superabsorbent such as thermal resistance, porous structure and uniform network structure. The superabsorbent hydrogel could absorb 1100 (g/g distilled water. The water absorption and water retention of superabsorbent were studied by loading it in 5 different soil texture classes which were 0:100, 25:75, 50:50, 75:25 and 100:0 mixture fractions of sand/loam soil. As a result, it was observed that in the first week after irrigation, the best retention of initial moisture belonged to the soil with 50% sand texture, and also the soil with sand texture returned to its initial weight after 53 days (i.e., 30 days later than the control sample.

  14. A versatile characterization of poly(N-isopropylacrylamideco-N,N!-methylene-bis-acrylamide) hydrogels for composition, mechanical strength, and rheology

    CSIR Research Space (South Africa)

    Chetty, A

    2013-01-01

    Full Text Available ?105 Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2013.9 *Corresponding author, e-mail: vvargha@mail.bme.hu ? BME-PT as biosensors [12], molecular imprinting [13], fluid microchips [14], as well as numerous biomedical...., Nishimura T., Ohashi K., Ohkouchi H., Nango M.: Two-step imprinting procedure of inter- penetrating polymer network-type stimuli-responsive hydrogel-adsorbents. Polymer Journal, 35, 545?550 (2003). DOI: 10.1295/polymj.35.545 [14] Sugiura S., Szil?gyi A...

  15. Natural fibers for hydrogels production and their applications in agriculture

    Directory of Open Access Journals (Sweden)

    Liliana Serna Cock

    2017-10-01

    Full Text Available This paper presents a review on hydrogels applied to agriculture emphasizing on the use of natural fibers. The objectives were to examine, trends in research addressed to identify natural fibers used in hydrogels development and methods for modifying natural fibers, understand factors which determine the water retention capacity of a hydrogel. Consequently, this paper shows some methodologies used to evaluate the hydrogels efficiency and to collect in tables, relevant information in relation to methods of natural fibers modification and hydrogel synthesis. It was found that previous research focused on hydrogels development processed with biodegradable polymers such as starch, chitosan and modified natural fibers, cross-linked with potassium acrylate and acrylamide, respectively. In addition, current researches aimed to obtaining hydrogels with improved properties, which have allowed a resistance to climatic variations and soil physicochemical changes, such as pH, presence of salts, temperature and composition. In fact, natural fibers such as sugarcane, agave fiber and kapok fiber, modified with maleic anhydride, are an alternative to obtain hydrogels due to an increasing of mechanical properties and chemically active sites. However, the use of natural nanofibers in hydrogels, has been a successful proposal to improve hydrogels mechanical and swelling properties, since they give to material an elasticity and rigidity properties. A hydrogel efficiency applied to soil, is measured throughout properties as swellability, mechanical strength, and soil water retention. It was concluded that hydrogels, are an alternative to the current needs for the agricultural sector.

  16. Thermosensitive membranes by radiation-induced graft polymerization of N-isopropyl acrylamide/acrylic acid on polypropylene nonwoven fabric

    International Nuclear Information System (INIS)

    Ikram, Saiqa; Kumari, Mamta; Gupta, Bhuvanesh

    2011-01-01

    Radiation-induced graft copolymerization of N-isopropylacrylamide (NIPAAm) and acrylic acid (AA) mixture was investigated on polypropylene nonwoven fabric to develop a thermosensitive material. The grafting was carried out using methanol, acetone and butanone as homopolymerization inhibitor in the reaction medium. Butanone was observed to give the maximum grafting. It was observed that the grafting is significantly influenced by the reaction conditions, such as radiation dose, monomer concentration, monomer ratio, solvent composition and reaction temperature. The degree of grafting increased as the AA and NIPAAm concentration in the reaction medium increased. The degree of grafting increased as the AA fraction in the NIPAAm/AA mixture increased. The temperature dependence of the grafting process is very much governed by the thermosensitive nature of the grafted chains right from the stage when initial grafting has taken place.

  17. Thermosensitive membranes by radiation-induced graft polymerization of N-isopropyl acrylamide/acrylic acid on polypropylene nonwoven fabric

    Energy Technology Data Exchange (ETDEWEB)

    Ikram, Saiqa; Kumari, Mamta [Department of Chemistry, Jamia Millia Islamia (Central University), New Delhi-110025 (India); Gupta, Bhuvanesh, E-mail: bgupta@textile.iitd.ernet.i [Department of Textile Technology, Indian Institute of Technology, New Delhi-110016 (India)

    2011-01-15

    Radiation-induced graft copolymerization of N-isopropylacrylamide (NIPAAm) and acrylic acid (AA) mixture was investigated on polypropylene nonwoven fabric to develop a thermosensitive material. The grafting was carried out using methanol, acetone and butanone as homopolymerization inhibitor in the reaction medium. Butanone was observed to give the maximum grafting. It was observed that the grafting is significantly influenced by the reaction conditions, such as radiation dose, monomer concentration, monomer ratio, solvent composition and reaction temperature. The degree of grafting increased as the AA and NIPAAm concentration in the reaction medium increased. The degree of grafting increased as the AA fraction in the NIPAAm/AA mixture increased. The temperature dependence of the grafting process is very much governed by the thermosensitive nature of the grafted chains right from the stage when initial grafting has taken place.

  18. 3D- Printed Poly(ε-caprolactone) Scaffold Integrated with Cell-laden Chitosan Hydrogels for Bone Tissue Engineering

    OpenAIRE

    Dong, Liang; Wang, Shao-Jie; Zhao, Xin-Rong; Zhu, Yu-Fang; Yu, Jia-Kuo

    2017-01-01

    Synthetic polymeric scaffolds are commonly used in bone tissue engineering (BTE) due to their biocompatibility and adequate mechanical properties. However, their hydrophobicity and the lack of specific cell recognition sites confined their practical application. In this study, to improve the cell seeding efficiency and osteoinductivity, an injectable thermo-sensitive chitosan hydrogel (CSG) was incorporated into a 3D-printed poly(ε-caprolactone) (PCL) scaffold to form a hybrid scaffold. To de...

  19. Hydrogel-based bioflocculants for the removal of organic pollutants from biodiesel wastewater

    CSIR Research Space (South Africa)

    Fosso-Kankeu, E

    2017-09-01

    Full Text Available hydrogels were characterized using X-Ray diffraction, Fourier transformed infra-red spectroscopy and scanning electron microscope. It was found that the synthesis provided the composite with the functional groups of the individual components. The hydrogels...

  20. Gradient Material Strategies for Hydrogel Optimization in Tissue Engineering Applications

    Science.gov (United States)

    2018-01-01

    Although a number of combinatorial/high-throughput approaches have been developed for biomaterial hydrogel optimization, a gradient sample approach is particularly well suited to identify hydrogel property thresholds that alter cellular behavior in response to interacting with the hydrogel due to reduced variation in material preparation and the ability to screen biological response over a range instead of discrete samples each containing only one condition. This review highlights recent work on cell–hydrogel interactions using a gradient material sample approach. Fabrication strategies for composition, material and mechanical property, and bioactive signaling gradient hydrogels that can be used to examine cell–hydrogel interactions will be discussed. The effects of gradients in hydrogel samples on cellular adhesion, migration, proliferation, and differentiation will then be examined, providing an assessment of the current state of the field and the potential of wider use of the gradient sample approach to accelerate our understanding of matrices on cellular behavior. PMID:29485612

  1. 3D-Printable Bioactivated Nanocellulose-Alginate Hydrogels.

    Science.gov (United States)

    Leppiniemi, Jenni; Lahtinen, Panu; Paajanen, Antti; Mahlberg, Riitta; Metsä-Kortelainen, Sini; Pinomaa, Tatu; Pajari, Heikki; Vikholm-Lundin, Inger; Pursula, Pekka; Hytönen, Vesa P

    2017-07-05

    We describe herein a nanocellulose-alginate hydrogel suitable for 3D printing. The composition of the hydrogel was optimized based on material characterization methods and 3D printing experiments, and its behavior during the printing process was studied using computational fluid dynamics simulations. The hydrogel was biofunctionalized by the covalent coupling of an enhanced avidin protein to the cellulose nanofibrils. Ionic cross-linking of the hydrogel using calcium ions improved the performance of the material. The resulting hydrogel is suitable for 3D printing, its mechanical properties indicate good tissue compatibility, and the hydrogel absorbs water in moist conditions, suggesting potential in applications such as wound dressings. The biofunctionalization potential was shown by attaching a biotinylated fluorescent protein and a biotinylated fluorescent small molecule via avidin and monitoring the material using confocal microscopy. The 3D-printable bioactivated nanocellulose-alginate hydrogel offers a platform for the development of biomedical devices, wearable sensors, and drug-releasing materials.

  2. Radiation preparation of drug carriers based on poly(N-isopropylacrylamide) hydrogels, their loading capacities and controlled release rates for dexamethasone and tegafur

    International Nuclear Information System (INIS)

    Hoang Dang Sang; Nguyen Van Binh; Tran Bang Diep; Nguyen Thi Thom; Hoang Phuong Thao; Pham Duy Duong; Tran Minh Quynh

    2015-01-01

    Thermo-sensitive hydrogels have great potential in some applications. In order to use as the drug delivery systems, the hydrogels should be biocompatibility. New polymers with more biocompatibility and better biodegradability, and environmental friendly crosslinking agents would be necessary for the successful drug carriers. Poly (N-isopropylacrylamide-co-dimethylacrylamide) based hydrogels have been prepared from the admixture solutions of N-isopropylacrylamide (NIPA) and N,N’-dimethyl acrylamide (DMA) by radiation copolymerization and crosslinking at radiation dose of 20 kGy as reported in our previous study. Water swelling behaviour of the resulting hydrogels were much depended on their nature such as initial ratio of NIPA and DMA. The drug-loaded hydrogels were prepared by merging hydrogel in the solutions containing corresponding drugs. Loading capacity of the hydrogels were about 48.6 and 95.7 mg per g dried hydrogel for dexamethasone and tegafur. The release studies showed that the presence of ions in simulated body fluid and temperature of the solution much affecting to in vitro release behaviors of hydrogels for dexamethasone and tegafur. The release rates were fast for both drug models. The result also revealed that these drug carriers were biocompatibility without skin irritation, suggested the drug-loaded hydrogels may be used as controlled release drug delivery systems. (author)

  3. Green Synthesis of Three-Dimensional MnO2/Graphene Hydrogel Composites as a High-Performance Electrode Material for Supercapacitors.

    Science.gov (United States)

    Meng, Xiaoyi; Lu, Liang; Sun, Chunwen

    2018-05-16

    Graphene hydrogels (GHs) and their composites have attracted wide attention because of the special structure of graphene assembly and exceptional electrochemical performance as electrodes for energy storage devices. Here, we report a GH with three-dimensional architecture prepared by a hydrothermal method via a self-assembled process in glucose and ammonia system as well as subsequent freeze-drying. The δ-MnO 2 /GH composite was then obtained by immersing GH in KMnO 4 solution with a certain concentration under heat treatment. The asymmetric supercapacitor MnO 2 /GH//GH consisting of pseudocapacitive nanosheet-like δ-MnO 2 /GH as the cathode and electric double-layer capacitive GH as the anode provides high energy density of 34.7 W h/kg at a power density of 1.0 kW/kg. Importantly, it is found that the pseudocapacitive behavior of MnO 2 has great effects on the rate performance of the supercapacitor, which is identified by kinetic analysis.

  4. Heparin release from thermosensitive polymer coatings: in vivo studies

    NARCIS (Netherlands)

    Gutowska, Anna; Bae, You Han; Jacobs, Harvey; Mohammad, Fazal; Mix, Donald; Feijen, Jan; Kim, Sung Wan

    1995-01-01

    Biomer/poly(N-isopropylacrylamide)/[poly(NiPAAm)] thermosensitive polymer blends were prepared and their application as heparin-releasing polymer coatings for the prevention of surface-induced thrombosis was examined. The advantage of using poly(NiPAAm)-based coatings as heparin-releasing polymers

  5. Radiation crosslinking of starch/water-soluble polymer blends for hydrogel

    International Nuclear Information System (INIS)

    Hashim, K.; Mohid, N.; Bahari, K.; Dahlan, K.Z.

    2000-01-01

    Water-soluble polymers such as PVP(polyvinyl pyrrolidone) and PVA(polyvinyl alcohol), in aqueous solution can form hydrogel easily upon gamma or electron beam irradiation. The properties of hydrogels, particularly for wound dressing application, can be further improved by adding sago starch to the blend. Results show improved gel strength and elongation properties of the hydrogel with increasing sago concentration. It was found that the PVA/sago hydrogel gives better gel strength and elongation than the PVP/sago hydrogel. The tackiness property of the PVA/sago hydrogel increased with increase amount of sago starch added. In case of PVP/sago hydrogel, the tackiness property shows significant increase with increasing amount of sago except for the 5%PVP composition. The swelling properties of PVP/sago and PVA/sago hydrogel decreased with increasing amount of sago but the crosslink density of the hydrogels also reduced. (author)

  6. Radiation crosslinking of starch/water-soluble polymer blends for hydrogel

    Energy Technology Data Exchange (ETDEWEB)

    Hashim, K.; Mohid, N.; Bahari, K.; Dahlan, K.Z. [Radiation Processing Technology Division, Malaysian Institute Nuclear Technology Research Malaysia (MINT), Bangi, 43000 Kajang (Malaysia)

    2000-03-01

    Water-soluble polymers such as PVP(polyvinyl pyrrolidone) and PVA(polyvinyl alcohol), in aqueous solution can form hydrogel easily upon gamma or electron beam irradiation. The properties of hydrogels, particularly for wound dressing application, can be further improved by adding sago starch to the blend. Results show improved gel strength and elongation properties of the hydrogel with increasing sago concentration. It was found that the PVA/sago hydrogel gives better gel strength and elongation than the PVP/sago hydrogel. The tackiness property of the PVA/sago hydrogel increased with increase amount of sago starch added. In case of PVP/sago hydrogel, the tackiness property shows significant increase with increasing amount of sago except for the 5%PVP composition. The swelling properties of PVP/sago and PVA/sago hydrogel decreased with increasing amount of sago but the crosslink density of the hydrogels also reduced. (author)

  7. Investigation of particle accumulation, chemosensitivity and thermosensitivity for effective solid tumor therapy using thermosensitive liposomes and hyperthermia

    NARCIS (Netherlands)

    W.J.M. Lokerse (Wouter); M. Bolkestein (Michiel); T.L.M. ten Hagen (Timo); M. de Jong (Marcel); A.M.M. Eggermont (Alexander); Grüll, H. (Holger); G.A. Koning (Gerben)

    2016-01-01

    textabstractDoxorubicin (Dox) loaded thermosensitive liposomes (TSLs) have shown promising results for hyperthermia-induced local drug delivery to solid tumors. Typically, the tumor is heated to hyperthermic temperatures (41-42 °C), which induced intravascular drug release from TSLs within the tumor

  8. Bioinspired Nanocomposite Hydrogels with Highly Ordered Structures.

    Science.gov (United States)

    Zhao, Ziguang; Fang, Ruochen; Rong, Qinfeng; Liu, Mingjie

    2017-12-01

    In the human body, many soft tissues with hierarchically ordered composite structures, such as cartilage, skeletal muscle, the corneas, and blood vessels, exhibit highly anisotropic mechanical strength and functionality to adapt to complex environments. In artificial soft materials, hydrogels are analogous to these biological soft tissues due to their "soft and wet" properties, their biocompatibility, and their elastic performance. However, conventional hydrogel materials with unordered homogeneous structures inevitably lack high mechanical properties and anisotropic functional performances; thus, their further application is limited. Inspired by biological soft tissues with well-ordered structures, researchers have increasingly investigated highly ordered nanocomposite hydrogels as functional biological engineering soft materials with unique mechanical, optical, and biological properties. These hydrogels incorporate long-range ordered nanocomposite structures within hydrogel network matrixes. Here, the critical design criteria and the state-of-the-art fabrication strategies of nanocomposite hydrogels with highly ordered structures are systemically reviewed. Then, recent progress in applications in the fields of soft actuators, tissue engineering, and sensors is highlighted. The future development and prospective application of highly ordered nanocomposite hydrogels are also discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Controlled release fertilizers using superabsorbent hydrogel prepared by gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Elbarbary, Ahmed M.; Ghobashy, Mohamed Mohamady [Atomic Energy Authority, Nasr City (Egypt). National Center for Radiation Research and Technology (NCRTT)

    2017-07-01

    Superabsorbent hydrogels (PVP/CMC) based on polyvinylpyrrolidone (PVP)/carboxylmethyl cellulose (CMC) of different copolymer compositions were prepared by gamma radiation. Factors affecting the gel content (%) and the swelling ratio (g/g) of hydrogel such as irradiation dose as well as copolymer composition were investigated. With increasing the CMC content in PVP/CMC hydrogels, increases the swelling and improves the water retention capability. The high swelling ratio was observed at copolymer composition of PVP/CMC (60/40). Fast swelling of the hydrogels was obtained after 20 min. The effect of different fertilizers and buffers of different pH's on equilibrium swelling of hydrogels was investigated. Fertilizers such as urea, monopotassium-phosphate (MPK), and nitrogen-phosphate-potassium (NPK) were loaded onto the hydrogel to supply nitrogen, potassium and phosphorous nutrients. PVP/CMC hydrogels retained 28-36% after 72 h and slow retention was noticed up to 9 days. The swelling of hydrogel in fertilizer solutions is lower than that in water. The hydrogels showed adsorption desorption of fertilizers which governs by slow release property. The release rate of urea is much higher 10 times than that of phosphate. After 3 days, urea released 60%, while phosphate released 10-12%. The applicability of PVP/CMC hydrogels in the agricultural fields shows greater growth effect on zea maize plants. The growth of zea maize plant in soil mixed with PVP/CMC hydrogels loaded fertilizers is greater than untreated soil. The slow release fertilize, the high swelling and the slow water retention behaviors of PVP/CMC hydrogels encourage their use as safer release systems for fertilizers and as soil conditioner in agricultural applications.

  10. Controlled release fertilizers using superabsorbent hydrogel prepared by gamma radiation

    International Nuclear Information System (INIS)

    Elbarbary, Ahmed M.; Ghobashy, Mohamed Mohamady

    2017-01-01

    Superabsorbent hydrogels (PVP/CMC) based on polyvinylpyrrolidone (PVP)/carboxylmethyl cellulose (CMC) of different copolymer compositions were prepared by gamma radiation. Factors affecting the gel content (%) and the swelling ratio (g/g) of hydrogel such as irradiation dose as well as copolymer composition were investigated. With increasing the CMC content in PVP/CMC hydrogels, increases the swelling and improves the water retention capability. The high swelling ratio was observed at copolymer composition of PVP/CMC (60/40). Fast swelling of the hydrogels was obtained after 20 min. The effect of different fertilizers and buffers of different pH's on equilibrium swelling of hydrogels was investigated. Fertilizers such as urea, monopotassium-phosphate (MPK), and nitrogen-phosphate-potassium (NPK) were loaded onto the hydrogel to supply nitrogen, potassium and phosphorous nutrients. PVP/CMC hydrogels retained 28-36% after 72 h and slow retention was noticed up to 9 days. The swelling of hydrogel in fertilizer solutions is lower than that in water. The hydrogels showed adsorption desorption of fertilizers which governs by slow release property. The release rate of urea is much higher 10 times than that of phosphate. After 3 days, urea released 60%, while phosphate released 10-12%. The applicability of PVP/CMC hydrogels in the agricultural fields shows greater growth effect on zea maize plants. The growth of zea maize plant in soil mixed with PVP/CMC hydrogels loaded fertilizers is greater than untreated soil. The slow release fertilize, the high swelling and the slow water retention behaviors of PVP/CMC hydrogels encourage their use as safer release systems for fertilizers and as soil conditioner in agricultural applications.

  11. Formulation and release of alaptide from cellulose-based hydrogels

    Directory of Open Access Journals (Sweden)

    Zbyněk Sklenář

    2012-01-01

    Full Text Available The modern drug alaptide, synthetic dipeptide, shows regenerative effects and effects on the epitelisation process. A commercial product consisting of 1% alaptide hydrophilic cream is authorised for use in veterinary practice. This study focuses on the formulation of alaptide into semi-synthetic polymer-based hydrogels. The aim of the present study is to prepare hydrogels and to evaluate the liberation of alaptide from hydrogels. The hydrogels were prepared on the basis of three gel-producing substances: methylcellulose, hydroxyethylcellulose and hydroxypropylcellulose. To enhance the drug release from hydrogel humectants, glycerol, propylene glycol and ethanol in various concentrations were evaluated. The permeation of the alaptide from gels into the acceptor solution was evaluated with the use of the permeable membrane neprophane. The amount of drug released from prepared hydrogels was determined spectrophotometrically. Hydrogels with optimal alaptide liberation properties were subjected to the study of rheological properties in the next phase. The optimal composition of hydrogel as established in this study was 1% alaptide + 3% hydroxyethylcellulose with the addition of 10% glycerol as humectant. Due to the advantageous properties of hydrogels in wounds, alaptide could be incorporated into a hydrogel base for use in veterinary medicine.

  12. Biomimetic Membrane Arrays on Cast Hydrogel Supports

    DEFF Research Database (Denmark)

    Roerdink-Lander, Monique; Ibragimova, Sania; Rein Hansen, Christian

    2011-01-01

    , provides mechanical support but at the cost of small molecule transport through the membrane−support sandwich. To stabilize biomimetic membranes while allowing transport through a membrane−support sandwich, we have investigated the feasibility of using an ethylene tetrafluoroethylene (ETFE......)/hydrogel sandwich as the support. The sandwich is realized as a perforated surface-treated ETFE film onto which a hydrogel composite support structure is cast. We report a simple method to prepare arrays of lipid bilayer membranes with low intrinsic electrical conductance on the highly permeable, self......-supporting ETFE/hydrogel sandwiches. We demonstrate how the ETFE/hydrogel sandwich support promotes rapid self-thinning of lipid bilayers suitable for hosting membrane-spanning proteins....

  13. Recovery of oxidative stress-induced damage in Cisd2-deficient cardiomyocytes by sustained release of ferulic acid from injectable hydrogel.

    Science.gov (United States)

    Cheng, Yung-Hsin; Lin, Feng-Huei; Wang, Chien-Ying; Hsiao, Chen-Yuan; Chen, Hung-Ching; Kuo, Hsin-Yu; Tsai, Ting-Fen; Chiou, Shih-Hwa

    2016-10-01

    Aging-related oxidative stress is considered a major risk factor of cardiovascular diseases (CVD) and could be associated with mitochondrial dysfunction and reactive oxygen species (ROS) overproduction. Cisd2 is an outer mitochondrial membrane protein and plays an important role in controlling the lifespan of mammals. Ferulic acid (FA), a natural antioxidant, is able to improve cardiovascular functions and inhibit the pathogenetic CVD process. However, directly administering therapeutics with antioxidant molecules is challenging because of stability and bioavailability issues. In the present study, thermosensitive chitosan-gelatin-based hydrogel containing FA was used to treat Cisd2-deficient (Cisd2(-/-)) cardiomyocytes (CM) derived from induced pluripotent stem cells of Cisd2(-/-) murine under oxidative stress. The results revealed that the developed hydrogel could provide a sustained release of FA and increase the cell viability. Post-treatment of FA-loaded hydrogel effectively decreased the oxidative stress-induced damage in Cisd2(-/-) CM via increasing catalase activity and decreasing endogenous reactive oxygen species (ROS) production. The in vivo biocompatibility of FA-loaded hydrogel was confirmed in subcutaneously injected rabbits and intramyocardially injected Cisd2(-/-) mice. These results suggest that the thermosensitive FA-loaded hydrogel could rescue Cisd2(-/-) CM from oxidative stress-induced damage and may have potential applications in the future treatment of CVD. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. The TRPM2 channel: A thermo-sensitive metabolic sensor.

    Science.gov (United States)

    Kashio, Makiko; Tominaga, Makoto

    2017-09-03

    Living organisms continually experience changes in ambient temperature. To detect such temperature changes for adaptive behavioral responses, we evolved the ability to sense temperature. Thermosensitive transient receptor potential (TRP) channels, so-called thermo-TRPs, are involved in many physiologic functions in diverse organisms and constitute important temperature sensors. One of the important roles of thermo-TRPs is detecting ambient temperature in sensory neurons. Importantly, the functional expression of thermo-TRPs is observed not only in sensory neurons but also in tissues and cells that are not exposed to drastic temperature changes, indicating that thermo-TRPs are involved in many physiologic functions within the body's normal temperature range. Among such thermo-TRPs, this review focuses on one thermo-sensitive metabolic sensor in particular, TRPM2, and summarizes recent progress to clarify the regulatory mechanisms and physiologic functions of TRPM2 at body temperature under various metabolic states.

  15. Thermosensitive liposomal drug delivery systems: state of the art review

    Directory of Open Access Journals (Sweden)

    Kneidl B

    2014-09-01

    Full Text Available Barbara Kneidl,1,2 Michael Peller,3 Gerhard Winter,2 Lars H Lindner,1 Martin Hossann11Department of Internal Medicine III, University Hospital Munich, 2Department of Pharmacy, Pharmaceutical Technology and Biopharmaceutics, 3Institute for Clinical Radiology, University Hospital Munich, Ludwig-Maximilians University, Munich, GermanyAbstract: Thermosensitive liposomes are a promising tool for external targeting of drugs to solid tumors when used in combination with local hyperthermia or high intensity focused ultrasound. In vivo results have demonstrated strong evidence that external targeting is superior over passive targeting achieved by highly stable long-circulating drug formulations like PEGylated liposomal doxorubicin. Up to March 2014, the Web of Science listed 371 original papers in this field, with 45 in 2013 alone. Several formulations have been developed since 1978, with lysolipid-containing, low temperature-sensitive liposomes currently under clinical investigation. This review summarizes the historical development and effects of particular phospholipids and surfactants on the biophysical properties and in vivo efficacy of thermosensitive liposome formulations. Further, treatment strategies for solid tumors are discussed. Here we focus on temperature-triggered intravascular and interstitial drug release. Drug delivery guided by magnetic resonance imaging further adds the possibility of performing online monitoring of a heating focus to calculate locally released drug concentrations and to externally control drug release by steering the heating volume and power. The combination of external targeting with thermosensitive liposomes and magnetic resonance-guided drug delivery will be the unique characteristic of this nanotechnology approach in medicine.Keywords: thermosensitive liposomes, phosphatidyloligoglycerol, hyperthermia, high intensity focused ultrasound, drug delivery, drug targeting

  16. Preparation of Composite Hydrogel Based on Polyacrylamide and the Effect of Kaolinite on Its Properties in the Reservoir Conditions

    OpenAIRE

    Farhad Salimi; Mohsen Vafaie; Mehdi Razzaghi Kashani; Majid Rafipoor

    2013-01-01

    A gel composite (based on polyacrylamide and crosslinker Cr(III) acetate) was prepared by solvent method (distillate and water formation) and nanoclay particle (kaolinite). Using XRD tests, d001 was evaluated for kaolinite nanoparticles in gel composite. Kaolinite modification using dimethyl-sulfoxide led to increase interlamellar spacing from 7.21 to 10.82 o A. Based on the results obtained for samples prepared from unmodified clay besides the pure clay, there is a wide peak at 2θ = 8o; whic...

  17. Thermosensitive liposomes entrapping iron oxide nanoparticles for controllable drug release

    International Nuclear Information System (INIS)

    Tai, L-A; Wang, Y-C; Wang, Y-J; Yang, C-S; Tsai, P-J; Lo, L-W

    2009-01-01

    Iron oxide nanoparticles can serve as a heating source upon alternative magnetic field (AMF) exposure. Iron oxide nanoparticles can be mixed with thermosensitive nanovehicles for hyperthermia-induced drug release, yet such a design and mechanism may not be suitable for controllable drug release applications in which the tissues are susceptible to environmental temperature change such as brain tissue. In the present study, iron oxide nanoparticles were entrapped inside of thermosensitive liposomes for AMF-induced drug release while the environmental temperature was maintained at a constant level. Carboxyfluorescein was co-entrapped with the iron oxide nanoparticles in the liposomes as a model compound for monitoring drug release and environmental temperature was maintained with a water circulator jacket. These experiments have been successfully performed in solution, in phantom and in anesthetized animals. Furthermore, the thermosensitive liposomes were administered into rat forearm skeletal muscle, and the release of carboxylfluorescein triggered by the external alternative magnetic field was monitored by an implanted microdialysis perfusion probe with an on-line laser-induced fluorescence detector. In the future such a device could be applied to simultaneous magnetic resonance imaging and non-invasive drug release in temperature-sensitive applications.

  18. Study of complex thermosensitive amphiphilic polyoxazolines and their interaction with ionic surfactants. Are hydrophobic, thermosensitive, and hydrophilic moieties equally important?

    Czech Academy of Sciences Publication Activity Database

    Bogomolova, Anna; Filippov, Sergey K.; Starovoytova, Larisa; Angelov, Borislav; Konarev, P.; Sedláček, Ondřej; Hrubý, Martin; Štěpánek, Petr

    2014-01-01

    Roč. 118, č. 18 (2014), s. 4940-4950 ISSN 1520-6106 R&D Projects: GA ČR GAP205/11/1657; GA MPO FR-TI4/625 Grant - others:AV ČR(CZ) M200501201 Program:M Institutional support: RVO:61389013 Keywords : poly(2-alkyl-2-oxazoline) * thermosensitivity * ionic surfactant Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.302, year: 2014

  19. Preparation of Composite Hydrogel Based on Polyacrylamide and the Effect of Kaolinite on Its Properties in the Reservoir Conditions

    Directory of Open Access Journals (Sweden)

    Farhad Salimi

    2013-01-01

    Full Text Available A gel composite (based on polyacrylamide and crosslinker Cr(III acetate was prepared by solvent method (distillate and water formation and nanoclay particle (kaolinite. Using XRD tests, d001 was evaluated for kaolinite nanoparticles in gel composite. Kaolinite modification using dimethyl-sulfoxide led to increase interlamellar spacing from 7.21 to 10.82 o A. Based on the results obtained for samples prepared from unmodified clay besides the pure clay, there is a wide peak at 2θ = 8o; which is a representative of polymer diffusion between the clay layers. For the sample prepared from modified clay, no increase in interlamellar space was observed. Addition of 15% clay (modified and unmodified caused the syneresis to reduce by 20%. The gelation time for composites prepared from both types of clays increased due to increases in clay concentration, which this increase for the sample prepared from unmodified clay was greater. The viscosity of gel for samples prepared from modified clay increased due to increased clay concentration, which reached its maximum for 15% clay concentration. However for unmodified clay the maximum value of viscosity was observed for 30% clay concentration.

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

    International Nuclear Information System (INIS)

    Abou El Fadl, F.I.; Maziad, N.A.

    2015-01-01

    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)

  1. 3D Printing of Aniline Tetramer-Grafted-Polyethylenimine and Pluronic F127 Composites for Electroactive Scaffolds.

    Science.gov (United States)

    Dong, Shi-Lei; Han, Lu; Du, Cai-Xia; Wang, Xiao-Yu; Li, Lu-Hai; Wei, Yen

    2017-02-01

    Electroactive hydrogel scaffolds are fabricated by the 3D-printing technique using composites of 30% Pluronic F127 and aniline tetramer-grafted-polyethylenimine (AT-PEI) copolymers with various contents from 2.5% to 10%. The synthesized AT-PEI copolymers can self-assemble into nanoparticles with the diameter of ≈50 nm and display excellent electroactivity due to AT conjugation. The copolymers are then homogeneously distributed into 30% Pluronic F127 solution by virtue of the thermosensitivity of F127, denoted as F/AT-PEI composites. Macroscopic photographs of latticed scaffolds elucidate their excellent printability of F/AT-PEI hydrogels for the 3D-printing technique. The conductivities of the printed F/AT-PEI scaffolds are all higher than 2.0 × 10 -3 S cm -1 , which are significantly improved compared with that of F127 scaffold with only 0.94 × 10 -3 S cm -1 . Thus, the F/AT-PEI scaffolds can be considered as candidates for application in electrical stimulation of tissue regeneration such as repair of muscle and cardiac nerve tissue. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Development of Thermosensitive Hydrogels of Chitosan, Sodium and Magnesium Glycerophosphate for Bone Regeneration Applications

    Czech Academy of Sciences Publication Activity Database

    Lišková, Jana; Bačáková, Lucie; Skwarczyńska, A. L.; Musial, O.; Bliznuk, V.; De Schamphelaere, K.; Modrzejewska, Z.; Douglas, T.E.L.

    2015-01-01

    Roč. 6, č. 2 (2015), s. 192-203 ISSN 2079-4983 R&D Projects: GA MŠk(CZ) EE2.3.30.0025 Institutional support: RVO:67985823 Keywords : chitosan * magnesium * mineralization Subject RIV: EI - Biotechnology ; Bionics

  3. Preliminary evaluation of a thermosensitive chitosan hydrogel for Echinococcus granulosus vaccine delivery.

    Science.gov (United States)

    Umair, Saleh; Pernthaner, Anton; Deng, Qing; Gibson, Blake; Hook, Sarah; Heath, David

    2017-03-15

    The EG95 vaccine is effective in protecting grazing animals from infection with Echinococcus granulosus. Six male lambs were used in the study, two were each vaccinated subcutaneously with 50μg EG95/1mg Quil-A, two animals were each vaccinated with 50μg EG95/1mg Quil-A in 1% chitosan thermolabile gel subcutaneously, and two animals served as non-vaccinated controls. Two vaccinations were given at a 7 week interval. Two vaccinations induced a significantly higher antibody titre in the chitosan group compared with the Quil-A only group. The chitosan vaccine group also had a significantly higher antibody titre compared with a positive control sera from vaccinated and challenged sheep. Incorporating the EG95/Quil-A vaccine in a thermo-responsive chitosan sol-gel stimulated, after the second injection, a high level of antibody absorbance which remained high for at least one year. This response was significantly greater than the response to vaccine without the gel. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Evaluation of fibroblasts adhesion and proliferation on alginate-gelatin crosslinked hydrogel.

    Directory of Open Access Journals (Sweden)

    Bapi Sarker

    Full Text Available Due to the relatively poor cell-material interaction of alginate hydrogel, alginate-gelatin crosslinked (ADA-GEL hydrogel was synthesized through covalent crosslinking of alginate di-aldehyde (ADA with gelatin that supported cell attachment, spreading and proliferation. This study highlights the evaluation of the physico-chemical properties of synthesized ADA-GEL hydrogels of different compositions compared to alginate in the form of films. Moreover, in vitro cell-material interaction on ADA-GEL hydrogels of different compositions compared to alginate was investigated by using normal human dermal fibroblasts. Viability, attachment, spreading and proliferation of fibroblasts were significantly increased on ADA-GEL hydrogels compared to alginate. Moreover, in vitro cytocompatibility of ADA-GEL hydrogels was found to be increased with increasing gelatin content. These findings indicate that ADA-GEL hydrogel is a promising material for the biomedical applications in tissue-engineering and regeneration.

  5. Biomimetic hydrogel materials

    Science.gov (United States)

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

    2000-01-01

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

  6. PVA hydrogel properties for biomedical application.

    Science.gov (United States)

    Jiang, Shan; Liu, Sha; Feng, Wenhao

    2011-10-01

    PVA has been proposed as a promising biomaterial suitable for tissue mimicking, vascular cell culturing and vascular implanting. In this research, a kind of transparent PVA hydrogel has been investigated in order to mimic the creatural soft tissue deformation during mini-invasive surgery with needle intervention, such as brachytherapy. Three kinds of samples with the same composition of 3 g PVA, 17 g de-ionized water, 80 g dimethyl-sulfoxide but different freeze/thaw cycles have been prepared. In order to investigate the structure and properties of polyvinyl alcohol hydrogel, micro-structure, mechanical property and deformation measurement have been conducted. As the SEM image comparison results show, with the increase of freeze/thaw cycles, PVA hydrogel revealed the similar micro-structure to porcine liver tissue. With uniaxial tensile strength test, the above composition with a five freeze/thaw cycle sample resulted in Young's modulus similar to that of porcine liver's property. Through the comparison of needle insertion deformation experiment and the clinical experiment during brachytherapy, results show that the PVA hydrogel had the same deformation property as prostate tissue. These transparent hydrogel phantom materials can be suitable soft tissue substitutes in needle intervention precision or pre-operation planning studies, particularly in the cases of mimicking creatural tissue deformation and analysing video camera images. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Antifouling properties of hydrogels

    International Nuclear Information System (INIS)

    Murosaki, Takayuki; Gong, Jian Ping; Ahmed, Nafees

    2011-01-01

    Marine sessile organisms easily adhere to submerged solids such as rocks, metals and plastics, but not to seaweeds and fishes, which are covered with soft and wet 'hydrogel'. Inspired by this fact, we have studied long-term antifouling properties of hydrogels against marine sessile organisms. Hydrogels, especially those containing hydroxy group and sulfonic group, show excellent antifouling activity against barnacles both in laboratory assays and in the marine environment. The extreme low settlement on hydrogels in vitro and in vivo is mainly caused by antifouling properties against the barnacle cypris. (topical review)

  8. Antifouling properties of hydrogels

    Directory of Open Access Journals (Sweden)

    Takayuki Murosaki, Nafees Ahmed and Jian Ping Gong

    2011-01-01

    Full Text Available Marine sessile organisms easily adhere to submerged solids such as rocks, metals and plastics, but not to seaweeds and fishes, which are covered with soft and wet 'hydrogel'. Inspired by this fact, we have studied long-term antifouling properties of hydrogels against marine sessile organisms. Hydrogels, especially those containing hydroxy group and sulfonic group, show excellent antifouling activity against barnacles both in laboratory assays and in the marine environment. The extreme low settlement on hydrogels in vitro and in vivo is mainly caused by antifouling properties against the barnacle cypris.

  9. Development of injectable hydrogels for nucleus pulposus replacement

    Science.gov (United States)

    Thomas, Jonathan D.

    Intervertebral disc degeneration has been reported as the underlying cause for 75% of cases of lower back pain and is marked by dehydration of the nucleus pulposus within the intervertebral disc. There have been many implant designs to replace the nucleus pulposus. Some researchers have proposed the replacement of the nucleus pulposus with hydrogel materials. The insertion of devices made from these materials further compromises the annulus of the disc. An ideal nucleus replacement could be injected into the disc space and form a solid in vivo. However, injectable replacements using curing elastomers and thermoplastic materials are not ideal because of the potentially harmful exothermic heat evolved from their reactions and the toxicity of the reactants used. We propose a hydrogel system that can be injected as a liquid at 25°C and solidified to yield a hydrogel within the intervertebral disc at 37°C. In aqueous solutions, these polymers have Lower Critical Solution Temperatures (LCST) between 25-37°C, making them unique candidate materials for this application. Poly(N-isopropylacrylamide) (PNIPAAm) is the most widely studied LCST polymer due to its drastic transition near body temperature. However, by itself, pure PNIPAAm forms a hydrogel that has low water content and can readily undergo plastic deformation. To increase the water content and impart elasticity to PNIPAAm hydrogels, grafted and branched hydrogel systems were created that incorporated the thermogelling PNIPAAm and hydrophilic poly(ethylene glycol) (PEG). In this research, the effects of polymer composition and monomer to initiator ratio, which controls polymer MW, on the in vitro swelling properties (mass, chemical, and compressive mechanical stability) of hydrogels formed from aqueous solutions of these polymers were evaluated. Immersion studies were also conducted in solutions to simulate the osmotic environment of the nucleus pulposus. The effects of repeated compression and unloading cycles

  10. On the Interaction between Superabsorbent Hydrogels and Cementitious Materials

    Science.gov (United States)

    Farzanian, Khashayar

    Autogenous shrinkage induced cracking is a major concern in high performance concretes (HPC), which are produced with low water to cement ratios. Internal curing to maintain high relative humidity in HPC with the use of an internal water reservoir has proven effective in mitigating autogenous shrinkage in HPC. Superabsorbent polymers (SAP) or hydrogels have received increasing attention as an internal curing agent in recent years. A key advantage of SAP is its versatility in size distribution and absorption/desorption characteristics, which allow it to be adapted to specific mix designs. Understanding the behavior of superabsorbent hydrogels in cementitious materials is critical for accurate design of internal curing. The primary goal of this study is to fundamentally understand the interaction between superabsorbent hydrogels and cementitious materials. In the first step, the effect of chemical and mechanical conditions on the absorption of hydrogels is investigated. In the second step, the desorption of hydrogels in contact with porous cementitious materials is examined to aid in understanding the mechanisms of water release from superabsorbent hydrogels (SAP) into cementitious materials. The dependence of hydrogel desorption on the microstructure of cementitious materials and relative humidity is studied. It is shown that the capillary forces developed at the interface between the hydrogel and cementitious materials increased the desorption of the hydrogels. The size of hydrogels is shown to influence desorption, beyond the known size dependence of bulk diffusion, through debonding from the cementitious matrix, thereby decreasing the effect of the Laplace pressure on desorption. In the third step, the desorption of hydrogels synthesized with varied chemical compositions in cementitious materials are investigated. The absorption, chemical structure and mechanical response of hydrogels swollen in a cement mixture are studied. The effect of the capillary forces on

  11. A cell-compatible PEO–PPO–PEO (Pluronic®)-based hydrogel stabilized through secondary structures

    International Nuclear Information System (INIS)

    Peng, Sydney; Lin, Ji-Yu; Cheng, Ming-Huei; Wu, Chih-Wei; Chu, I-Ming

    2016-01-01

    Pluronic F-127 (PF127) is a thermosensitive polymer that has been widely recognized as a potential candidate for various bio-applications. However, in hydrogel form, its rapid disintegration and inhospitality toward cells have significantly limited its usage. As a means to increase the integrity and cell compatibility of a PF127 hydrogel, we propose the introduction of stabilizing secondary structures to the gel network by the addition of secondary structure-forming oligo-alanine and oligo-phenylalanine. Results indicate that increasing the oligo(peptides) attached to PF127 led to a significant decrease in the gelation concentration and temperature. A selected oligo(peptide)-modified PF127 was capable of forming a stable hydrogel network at 5% and suffered only 20% weight loss after 7 days of incubation in media. Scanning electron microscopy (SEM) revealed comparably more interconnected morphology in modified hydrogels which may be attributed to the presence of secondary structures, as verified by circular dichroism (CD) and Fourier-transformed infrared (FT-IR) spectroscopy. Nuclear magnetic resonance (NMR) provided insights into the extensive interactions at the micelle core, which is the key to altered gelation behavior. Furthermore, modified hydrogels maintained structural integrity within culturing media and supported the proliferation of encapsulated chondrocytes. In addition, in vivo residence time was extended to well beyond 2 weeks after oligo(peptide) modification, thereby broadening the application scope of the PF127 hydrogel to encompass long-term drug delivery and cell culturing. - Highlights: • Modification of Pluronic-F127 with oligo(peptides) decreased gelation concentration and prolonged residence time in vitro and in vivo. • Oligo(peptide)-modified Pluronic-F127 exhibited critical gelation concentration as low as 5%. • Cells encapsulated within 5% oligo(peptide)-modified hydrogel proliferated within a period of 7 days. • Oligo

  12. A cell-compatible PEO–PPO–PEO (Pluronic®)-based hydrogel stabilized through secondary structures

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Sydney; Lin, Ji-Yu [Deparment of Chemical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Cheng, Ming-Huei [Division of Microsurgery Reconstructive Microsurgery, Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, College of Medicine, Chang Gung University, Taoyuan, Taiwan (China); Center for Tissue Engineering, Chang Gung Memorial Hospital, Taoyuan, Taiwan (China); Wu, Chih-Wei, E-mail: drwu.jerry@gmail.com [Division of Microsurgery Reconstructive Microsurgery, Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, College of Medicine, Chang Gung University, Taoyuan, Taiwan (China); Center for Tissue Engineering, Chang Gung Memorial Hospital, Taoyuan, Taiwan (China); Chu, I-Ming, E-mail: chuiming456@gmail.com [Deparment of Chemical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2016-12-01

    Pluronic F-127 (PF127) is a thermosensitive polymer that has been widely recognized as a potential candidate for various bio-applications. However, in hydrogel form, its rapid disintegration and inhospitality toward cells have significantly limited its usage. As a means to increase the integrity and cell compatibility of a PF127 hydrogel, we propose the introduction of stabilizing secondary structures to the gel network by the addition of secondary structure-forming oligo-alanine and oligo-phenylalanine. Results indicate that increasing the oligo(peptides) attached to PF127 led to a significant decrease in the gelation concentration and temperature. A selected oligo(peptide)-modified PF127 was capable of forming a stable hydrogel network at 5% and suffered only 20% weight loss after 7 days of incubation in media. Scanning electron microscopy (SEM) revealed comparably more interconnected morphology in modified hydrogels which may be attributed to the presence of secondary structures, as verified by circular dichroism (CD) and Fourier-transformed infrared (FT-IR) spectroscopy. Nuclear magnetic resonance (NMR) provided insights into the extensive interactions at the micelle core, which is the key to altered gelation behavior. Furthermore, modified hydrogels maintained structural integrity within culturing media and supported the proliferation of encapsulated chondrocytes. In addition, in vivo residence time was extended to well beyond 2 weeks after oligo(peptide) modification, thereby broadening the application scope of the PF127 hydrogel to encompass long-term drug delivery and cell culturing. - Highlights: • Modification of Pluronic-F127 with oligo(peptides) decreased gelation concentration and prolonged residence time in vitro and in vivo. • Oligo(peptide)-modified Pluronic-F127 exhibited critical gelation concentration as low as 5%. • Cells encapsulated within 5% oligo(peptide)-modified hydrogel proliferated within a period of 7 days. • Oligo

  13. Nano-fibrin stabilized CaSO4 crystals incorporated injectable chitin composite hydrogel for enhanced angiogenesis & osteogenesis.

    Science.gov (United States)

    Arun Kumar, R; Sivashanmugam, A; Deepthi, S; Bumgardner, Joel D; Nair, Shantikumar V; Jayakumar, R

    2016-04-20

    Calcium sulfate (CaSO4), an excellent biodegradable bone forming agent that is an ideal choice as additive in gels, however, its disadvantage being poor gel rheology and angiogenesis. Here, we have synthesized chitin-CaSO4-nano-fibrin based injectable gel system which shows improved rheology and angiogenic potential. Rheological studies showed that the composite gel was a shear thinning gel with elastic modulus of 15.4±0.275kPa; a 1.67 fold increase over chitin control. SEM and XRD analyses revealed the effect of nano-fibrin (nFibrin) in transforming CaSO4 crystal shape from needle to hexagonal. It also masked the retarding effect of CaSO4 towards in vitro early cell attachment and angiogenesis using rabbit adipose derived mesenchymal stem cells (rASCs) and HUVECs, respectively. rASCs osteogenesis was confirmed by spectrophotometric endpoint assay, which showed 6-fold early increase in alkaline phosphatase levels and immuno-cytochemistry analysis. These in vitro results highlight the potential of injectable chitin-CaSO4-nFibrin gel for osteo-regeneration via enhanced angiogenesis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. A thermo-responsive and photo-polymerizable chondroitin sulfate-based hydrogel for 3D printing applications.

    Science.gov (United States)

    Abbadessa, A; Blokzijl, M M; Mouser, V H M; Marica, P; Malda, J; Hennink, W E; Vermonden, T

    2016-09-20

    The aim of this study was to design a hydrogel system based on methacrylated chondroitin sulfate (CSMA) and a thermo-sensitive poly(N-(2-hydroxypropyl) methacrylamide-mono/dilactate)-polyethylene glycol triblock copolymer (M15P10) as a suitable material for additive manufacturing of scaffolds. CSMA was synthesized by reaction of chondroitin sulfate with glycidyl methacrylate (GMA) in dimethylsulfoxide at 50°C and its degree of methacrylation was tunable up to 48.5%, by changing reaction time and GMA feed. Unlike polymer solutions composed of CSMA alone (20% w/w), mixtures based on 2% w/w of CSMA and 18% of M15P10 showed strain-softening, thermo-sensitive and shear-thinning properties more pronounced than those found for polymer solutions based on M15P10 alone. Additionally, they displayed a yield stress of 19.2±7.0Pa. The 3D printing of this hydrogel resulted in the generation of constructs with tailorable porosity and good handling properties. Finally, embedded chondrogenic cells remained viable and proliferating over a culture period of 6days. The hydrogel described herein represents a promising biomaterial for cartilage 3D printing applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Surface-modified silk hydrogel containing hydroxyapatite nanoparticle with hyaluronic acid-dopamine conjugate.

    Science.gov (United States)

    Kim, Hyung Hwan; Park, Jong Bo; Kang, Min Ji; Park, Young Hwan

    2014-09-01

    Silk fibroin/hydroxyapatite (SF/HAp) composite hydrogels were fabricated in this study, having different HAp contents (0-33 wt%) in SF matrix hydrogel. Surface modification of HAp nanoparticle with hyaluronic acid (HA)-dopamine (DA) conjugate improved a dispersibility of HAp in aqueous SF solution due to its negatively charged surface and therefore, fabrication of the SF composite hydrogel having HAp nanoparticles inside could be possible. Zeta potential of surface-modified HAP was examined by ELS. It demonstrates that surface of HAp was well modified to a negative charge with HA-DA. Morphological structure of SF hydrogel containing surface-modified HAp was examined by FE-SEM for analyzing pore structure of hydrogel and deposition of HAp nanoparticle in SF hydrogel. It was found that HAp nanoparticles were uniformly deposited on the pore wall of SF hydrogel. Structural characteristics of SF/HAp composite hydrogel was performed using X-ray diffraction and FT-IR analysis. It was found that β-sheet crystal conformation of SF was significantly influenced by the HAp content during gelation of a mixture of SF and HAp. As a result of MTT assay, the SF/HAp composite hydrogel showed excellent cell proliferation ability. Therefore, it is expected that SF hydrogel containing HAp nanoparticles has a high potential as bone regeneration scaffold. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Methacrylate hydrogels reinforced with bacterial cellulose

    Czech Academy of Sciences Publication Activity Database

    Hobzová, Radka; Dušková-Smrčková, Miroslava; Michálek, Jiří; Karpushkin, Evgeny; Gatenholm, P.

    2012-01-01

    Roč. 61, č. 7 (2012), s. 1193-1201 ISSN 0959-8103 R&D Projects: GA AV ČR KJB400500902 Institutional research plan: CEZ:AV0Z40500505 Keywords : bacterial cellulose * methacrylate hydrogel * composite Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.125, year: 2012

  17. Sustained release of intravitreal flurbiprofen from a novel drug-in-liposome-in-hydrogel formulation.

    Science.gov (United States)

    Pachis, K; Blazaki, S; Tzatzarakis, M; Klepetsanis, P; Naoumidi, E; Tsilimbaris, M; Antimisiaris, S G

    2017-11-15

    A novel Flurbiprofen (FLB)-in-liposome-in-hydrogel formulation was developed, as a method to sustain the release and increase the ocular bioavailability of FLB following intravitreal injection. For this, FLB loading into liposomes was optimized and liposomes were entrapped in thermosensitive hydrogels consisted of Pluronic F-127 (P). FLB solution, liposomes, and FLB dissolved in hydrogel were also used as control formulations. Actively loaded liposomes were found to be optimal for high FLB loading and small size, while in vitro studies revealed that P concentration of 18% (w/v) was best to retain the integrity of the hydrogel-dispersed liposome, compared to a 20% concentration. The in vitro release of FLB was significantly sustained when FLB-liposomes were dispersed in the hydrogel compared to hydrogel dissolved FLB, as well as the other control formulations. In vivo studies were carried out in pigmented rabbits which were injected through a 27G needle with 1mg/mL FLB in the different formulation-types. Ophthalmic examinations after intravitreal injection of all FLB formulations, revealed no evidence of inflammation, hemorrhage, uveitis or endophthalmitis. Pharmacokinetic analysis results confirm that the hybrid drug delivery system increases the bioavailability (by 1.9 times compared to solution), and extends the presence of the drug in the vitreous cavity, while liposome and hydrogel formulations demonstrate intermediate performance. Furthermore the hybrid system increases MRT of FLB in aqueous humor and retina/choroid tissues, compared to all the control formulations. Currently the potential therapeutic advances of FLB sustained release formulations for IVT administration are being evaluated. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Biocompatibility of hydrogel-based scaffolds for tissue engineering applications.

    Science.gov (United States)

    Naahidi, Sheva; Jafari, Mousa; Logan, Megan; Wang, Yujie; Yuan, Yongfang; Bae, Hojae; Dixon, Brian; Chen, P

    2017-09-01

    Recently, understanding of the extracellular matrix (ECM) has expanded rapidly due to the accessibility of cellular and molecular techniques and the growing potential and value for hydrogels in tissue engineering. The fabrication of hydrogel-based cellular scaffolds for the generation of bioengineered tissues has been based on knowledge of the composition and structure of ECM. Attempts at recreating ECM have used either naturally-derived ECM components or synthetic polymers with structural integrity derived from hydrogels. Due to their increasing use, their biocompatibility has been questioned since the use of these biomaterials needs to be effective and safe. It is not surprising then that the evaluation of biocompatibility of these types of biomaterials for regenerative and tissue engineering applications has been expanded from being primarily investigated in a laboratory setting to being applied in the multi-billion dollar medicinal industry. This review will aid in the improvement of design of non-invasive, smart hydrogels that can be utilized for tissue engineering and other biomedical applications. In this review, the biocompatibility of hydrogels and design criteria for fabricating effective scaffolds are examined. Examples of natural and synthetic hydrogels, their biocompatibility and use in tissue engineering are discussed. The merits and clinical complications of hydrogel scaffold use are also reviewed. The article concludes with a future outlook of the field of biocompatibility within the context of hydrogel-based scaffolds. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Thermo-sensitive and swelling properties of cellouronic acid sodium/poly (acrylamide-co-diallyldimethylammonium chloride) semi-IPN.

    Science.gov (United States)

    Zhang, Heng; Gao, Xin; Chen, Keli; Li, Hui; Peng, Lincai

    2018-02-01

    In current study, cellouronic acid sodium (CAS), obtained from bagasse pith, has been introduced into poly(acrylamide-co-diallyldimethylammonium chloride) (poly(AM-co-DAC)) network to form novel thermo-sensitive semi-IPNs. The structure and morphology of the hydrogels were proved by Fourier transformation infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The effects of CAS content, initiator charge, cross-linker dosage and swelling-medium property on the thermo-responsive water absorptivity were investigated in detail. The results elucidated that the prepared gels exhibited a thermo-sensibility with an upper critical solution temperature (UCST) and a high water-absorbency. And the values of UCST and equilibrium swelling ratio largely depended on the inner structure of the semi-IPNs and the external solvent property. It was also revealed that the swelling process conformed to the Schott's pseudo second order model and diffusion type was non-Fickian diffusion. The value of activation energy for this polyelectrolyte was found to be 8.74kJ/mol. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Preparation and characterization of smart magnetic hydrogels and its use for drug release

    International Nuclear Information System (INIS)

    Liu, T.-Y.; Hu, S.-H.; Liu, K.-H.; Liu, D.-M.; Chen, S.-Y.

    2006-01-01

    The magnetic hydrogels were successfully fabricated by chemically cross-linking of gelatin hydrogels and Fe 3 O 4 nanoparticles (ca. 40-60 nm) through genipin (GP) as cross-linking agent. The cross-sectional SEM observation demonstrates that the Fe 3 O 4 nanoparticles were fairly uniformly distributed in the gelatin matrix. Moreover, in vitro release data reveal that drug release profile of the resulting hydrogels is controllable by switching on or off mode of a given magnetic field. While applying magnetic fields to the magnetic hydrogels, the release rate of vitamin B 12 of the hydrogels was considerably decreased as compared with those when the field was turned off, suggesting a close configuration of the hydrogels as a result of the aggregation of Fe 3 O 4 nanoparticles. Based on this on- and -off mechanism, the smart magnetic hydrogels based on the gelatin-ferrite hybrid composites can be potentially developed for application in novel drug delivery systems

  1. Hydrogels That Allow and Facilitate Bone Repair, Remodeling, and Regeneration.

    Science.gov (United States)

    Short, Aaron R; Koralla, Deepthi; Deshmukh, Ameya; Wissel, Benjamin; Stocker, Benjamin; Calhoun, Mark; Dean, David; Winter, Jessica O

    2015-10-28

    Bone defects can originate from a variety of causes, including trauma, cancer, congenital deformity, and surgical reconstruction. Success of the current "gold standard" treatment (i.e., autologous bone grafts) is greatly influenced by insufficient or inappropriate bone stock. There is thus a critical need for the development of new, engineered materials for bone repair. This review describes the use of natural and synthetic hydrogels as scaffolds for bone tissue engineering. We discuss many of the advantages that hydrogels offer as bone repair materials, including their potential for osteoconductivity, biodegradability, controlled growth factor release, and cell encapsulation. We also discuss the use of hydrogels in composite devices with metals, ceramics, or polymers. These composites are useful because of the low mechanical moduli of hydrogels. Finally, the potential for thermosetting and photo-cross-linked hydrogels as three-dimensionally (3D) printed, patient-specific devices is highlighted. Three-dimensional printing enables controlled spatial distribution of scaffold materials, cells, and growth factors. Hydrogels, especially natural hydrogels present in bone matrix, have great potential to augment existing bone tissue engineering devices for the treatment of critical size bone defects.

  2. Gelatin- and starch-based hydrogels. Part A: Hydrogel development, characterization and coating.

    Science.gov (United States)

    Van Nieuwenhove, Ine; Salamon, Achim; Peters, Kirsten; Graulus, Geert-Jan; Martins, José C; Frankel, Daniel; Kersemans, Ken; De Vos, Filip; Van Vlierberghe, Sandra; Dubruel, Peter

    2016-11-05

    The present work aims at constructing the ideal scaffold matrix of which the physico-chemical properties can be altered according to the targeted tissue regeneration application. Ideally, this scaffold should resemble the natural extracellular matrix (ECM) as close as possible both in terms of chemical composition and mechanical properties. Therefore, hydrogel films were developed consisting of methacrylamide-modified gelatin and starch-pentenoate building blocks because the ECM can be considered as a crosslinked hydrogel network consisting of both polysaccharides and structural, signaling and cell-adhesive proteins. For the gelatin hydrogels, three different substitution degrees were evaluated including 31%, 72% and 95%. A substitution degree of 32% was applied for the starch-pentenoate building block. Pure gelatin hydrogels films as well as interpenetrating networks with gelatin and starch were developed. Subsequently, these films were characterized using gel fraction and swelling experiments, high resolution-magic angle spinning (1)H NMR spectroscopy, rheology, infrared mapping and atomic force microscopy. The results indicate that both the mechanical properties and the swelling extent of the developed hydrogel films can be controlled by varying the chemical composition and the degree of substitution of the methacrylamide-modified gelatin applied. The storage moduli of the developed materials ranged between 14 and 63kPa. Phase separation was observed for the IPNs for which separated starch domains could be distinguished located in the surrounding gelatin matrix. Furthermore, we evaluated the affinity of aggrecan for gelatin by atomic force microscopy and radiolabeling experiments. We found that aggrecan can be applied as a bioactive coating for gelatin hydrogels by a straightforward physisorption procedure. Thus, we achieved distinct fine-tuning of the physico-chemical properties of these hydrogels which render them promising candidates for tissue engineering

  3. Radiation synthesis of stimuli-responsive membranes, hydrogels and adsorbents for separation purposes. Final report of a coordinated research project 2000-2004

    International Nuclear Information System (INIS)

    2005-08-01

    This coordinated research project coordinated research work for the development of novel materials prepared by radiation processing techniques. Single and multi-pore polyamide membranes, fast thermo-responsive hydrogels, porous polymer monoliths, stimuli-responsive hydrogels based on natural and synthetic polymers, temperature responsive membranes, selective adsorbents, polymeric nanogels and novel non-ionic thermo-sensitive hydrogels were produced. The application areas explored for beneficially utilizing these novel materials included specialized drug delivery systems (DDS), selective adsorbents, nanopores for single molecule detection, membranes for separation and concentration of solutes, health care and remediation of environmental pollution. The report provides basic information on radiation processing and promotes experience exchange for further developments of radiation technology. Protocols and procedures of preparation of various stimuli responsive membranes and their actual and perspective applications are described in the report. Public awareness and technology acceptance are other factors to be considered for further dissemination. This publication summarizes the present status and the prospects of this technology

  4. Synthesis and Characterization of Chemically Cross-Linked Acrylic Acid/Gelatin Hydrogels: Effect of pH and Composition on Swelling and Drug Release

    Directory of Open Access Journals (Sweden)

    Syed Majid Hanif Bukhari

    2015-01-01

    Full Text Available This present work was aimed at synthesizing pH-sensitive cross-linked AA/Gelatin hydrogels by free radical polymerization. Ammonium persulfate and ethylene glycol dimethacrylate (EGDMA were used as initiator and as cross-linking agent, respectively. Different feed ratios of acrylic acid, gelatin, and EGDMA were used to investigate the effect of monomer, polymer, and degree of cross-linking on swelling and release pattern of the model drug. The swelling behavior of the hydrogel samples was studied in 0.05 M USP phosphate buffer solutions of various pH values pH 1.2, pH 5.5, pH 6.5, and pH 7.5. The prepared samples were evaluated for porosity and sol-gel fraction analysis. Pheniramine maleate used for allergy treatment was loaded as model drug in selected samples. The release study of the drug was investigated in 0.05 M USP phosphate buffer of varying pH values (1.2, 5.5, and 7.5 for 12 hrs. The release data was fitted to various kinetic models to study the release mechanism. Hydrogels were characterized by Fourier transformed infrared (FTIR spectroscopy which confirmed formation of structure. Surface morphology of unloaded and loaded samples was studied by surface electron microscopy (SEM, which confirmed the distribution of model drug in the gel network.

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

    International Nuclear Information System (INIS)

    Deghiedy, N.M.A.

    2010-01-01

    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. Sustained Release of Protein Therapeutics from Subcutaneous Thermosensitive Biocompatible and Biodegradable Pentablock Copolymers (PTSgels

    Directory of Open Access Journals (Sweden)

    Elizabeth Schaefer

    2016-01-01

    Full Text Available Objective. To evaluate thermosensitive, biodegradable pentablock copolymers (PTSgel for sustained release and integrity of a therapeutic protein when injected subcutaneously. Materials and Methods. Five PTSgels with PEG-PCL-PLA-PCL-PEG block arrangements were synthesized. In vitro release of IgG from PTSgels and concentrations was evaluated at 37°C. Released IgG integrity was characterized by SDS-PAGE. In vitro disintegration for 10GH PTSgel in PBS was monitored at 37°C over 72 days using gravimetric loss and GPC analysis. Near-infrared IgG in PTSgel was injected subcutaneously and examined by in vivo imaging and histopathology for up to 42 days. Results. IgG release was modulated from approximately 7 days to more than 63 days in both in vitro and in vivo testing by varying polymer composition, concentration of PTSgel aqueous solution, and concentration of IgG. Released IgG in vitro maintained structural integrity by SDS-PAGE. Subcutaneous PTSgels were highly biocompatible and in vitro IgG release occurred in parallel with the disappearance of subcutaneous gel in vivo. Conclusions. Modulation of release of biologics to fit the therapeutic need can be achieved by varying the biocompatible and biodegradable PTSgel composition. Release of IgG parallels disappearance of the polymeric gel; hence, little or no PTSgel remains after drug release is complete.

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

    Science.gov (United States)

    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.

  8. Thermosensitive gating effect and selective gas adsorption in a porous coordination nanocage

    NARCIS (Netherlands)

    Zhao, D.; Yuan, D.; Krishna, R.; van Baten, J.M.; Zhou, H.C.

    2010-01-01

    A porous coordination nanocage functionalized with 24 triisopropylsilyl groups exhibits a remarkable thermosensitive gate opening phenomenon and demonstrates a molecular sieving effect at a certain temperature range, which can be used for gas separation purposes.

  9. MRI monitoring of nanocarrier accumulation and release using Gadolinium-SPIO co-labelled thermosensitive liposomes

    NARCIS (Netherlands)

    Lorenzato, Cyril; Oerlemans, Chris; van Elk, Merel; Geerts, Willie J C; Denis de Senneville, Baudouin; Moonen, Chrit; Bos, Clemens

    2016-01-01

    Encapsulation of anticancer drugs in triggerable nanocarriers can beneficially modify pharmacokinetics and biodistribution of chemotherapeutic drugs, and consequently increase tumor drug concentration and efficacy, while reducing side effects. Thermosensitive liposomes release their contents

  10. Pharmacokinetics, Tissue Distribution and Therapeutic Effect of Cationic Thermosensitive Liposomal Doxorubicin Upon Mild Hyperthermia

    OpenAIRE

    Dicheva, Bilyana M.; Seynhaeve, Ann L. B.; Soulie, Thomas; Eggermont, Alexander M. M.; ten Hagen, Timo L. M.; Koning, Gerben A.

    2015-01-01

    textabstractPurpose: To evaluate pharmacokinetic profile, biodistribution and therapeutic effect of cationic thermosensitive liposomes (CTSL) encapsulating doxorubicin (Dox) upon mild hyperthermia (HT). Methods: Non-targeted thermosensitive liposomes (TSL) and CTSL were developed, loaded with Dox and characterized. Blood kinetics and biodistribution of Dox-TSL and Dox-CTSL were followed in B16BL6 tumor bearing mice upon normothermia (NT) or initial hyperthermia conditions. Efficacy study in B...

  11. Polypeptide based hydrogels

    OpenAIRE

    Hanay, Saltuk

    2018-01-01

    There is a need for biocompatible, biodegradable, 3-D printable and stable hydrogels especially in the areas of tissue engineering, drug delivery, bio-sensing technologies and antimicrobial coatings. The main aim of this Ph.D. work was to fabricate polypeptide based hydrogel which may find a potential application in those fields. Focusing on tyrosine or tryptophan-containing copolypeptides prepared by NCarboxyanhydride (NCA) polymerizations, three different crosslinking strategies have been t...

  12. Composite material

    Science.gov (United States)

    Hutchens, Stacy A [Knoxville, TN; Woodward, Jonathan [Solihull, GB; Evans, Barbara R [Oak Ridge, TN; O'Neill, Hugh M [Knoxville, TN

    2012-02-07

    A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft material. A method of tissue repair within the body of animals includes the steps of providing a composite biocompatible hydrogel material including a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa, and inserting the hydrogel material into cartilage or bone tissue of an animal, wherein the hydrogel material supports cell colonization in vitro for autologous cell seeding.

  13. Multimodal targeted high relaxivity thermosensitive liposome for in vivo imaging

    Science.gov (United States)

    Kuijten, Maayke M. P.; Hannah Degeling, M.; Chen, John W.; Wojtkiewicz, Gregory; Waterman, Peter; Weissleder, Ralph; Azzi, Jamil; Nicolay, Klaas; Tannous, Bakhos A.

    2015-11-01

    Liposomes are spherical, self-closed structures formed by lipid bilayers that can encapsulate drugs and/or imaging agents in their hydrophilic core or within their membrane moiety, making them suitable delivery vehicles. We have synthesized a new liposome containing gadolinium-DOTA lipid bilayer, as a targeting multimodal molecular imaging agent for magnetic resonance and optical imaging. We showed that this liposome has a much higher molar relaxivities r1 and r2 compared to a more conventional liposome containing gadolinium-DTPA-BSA lipid. By incorporating both gadolinium and rhodamine in the lipid bilayer as well as biotin on its surface, we used this agent for multimodal imaging and targeting of tumors through the strong biotin-streptavidin interaction. Since this new liposome is thermosensitive, it can be used for ultrasound-mediated drug delivery at specific sites, such as tumors, and can be guided by magnetic resonance imaging.

  14. Generation of composites for bone tissue-engineering applications consisting of gellan gum hydrogels mineralized with calcium and magnesium phosphate phases by enzymatic means.

    Science.gov (United States)

    Douglas, Timothy E L; Krawczyk, Grzegorz; Pamula, Elzbieta; Declercq, Heidi A; Schaubroeck, David; Bucko, Miroslaw M; Balcaen, Lieve; Van Der Voort, Pascal; Bliznuk, Vitaliy; van den Vreken, Natasja M F; Dash, Mamoni; Detsch, Rainer; Boccaccini, Aldo R; Vanhaecke, Frank; Cornelissen, Maria; Dubruel, Peter

    2016-11-01

    Mineralization of hydrogels, desirable for bone regeneration applications, may be achieved enzymatically by incorporation of alkaline phosphatase (ALP). ALP-loaded gellan gum (GG) hydrogels were mineralized by incubation in mineralization media containing calcium and/or magnesium glycerophosphate (CaGP, MgGP). Mineralization media with CaGP:MgGP concentrations 0.1:0, 0.075:0.025, 0.05:0.05, 0.025:0.075 and 0:0.1 (all values mol/dm 3 , denoted A, B, C, D and E, respectively) were compared. Mineral formation was confirmed by IR and Raman, SEM, ICP-OES, XRD, TEM, SAED, TGA and increases in the the mass fraction of the hydrogel not consisting of water. Ca was incorporated into mineral to a greater extent than Mg in samples mineralized in media A-D. Mg content and amorphicity of mineral formed increased in the order A hydroxyapatite (CDHA). Mineral formed in medium C was a combination of CDHA and an amorphous phase. Mineral formed in medium D was an amorphous phase. Mineral formed in medium E was a combination of crystalline and amorphous MgP. Young's moduli and storage moduli decreased in dependence of mineralization medium in the order A > B > C > D, but were significantly higher for samples mineralized in medium E. The attachment and vitality of osteoblastic MC3T3-E1 cells were higher on samples mineralized in media B-E (containing Mg) than in those mineralized in medium A (not containing Mg). All samples underwent degradation and supported the adhesion of RAW 264.7 monocytic cells, and samples mineralized in media A and B supported osteoclast-like cell formation. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

  15. Gamma radiation synthesis of super absorbent hydrogels for different applications

    International Nuclear Information System (INIS)

    Marzouk, H.M.G.

    2015-01-01

    Super absorbent polymers (SAP) of carboxymethyl cellulose/acrylamide (CMC/PAM), carboxymethyl cellulose/acrylamide/Silica (CMC/AM/Si) and carboxymethyl cellulose/Polyvinyl alcohol (CMC/PVA) were synthesized by radiation-induced grafting using γ-irradiation technique. The effects of various parameters, such as irradiation dose, the content of CMC, PAM, PVA, and Silica gel on the swelling percent of produced hydrogels have been evaluated. The kinetic equilibrium swelling of the prepared copolymer hydrogels was studied, it was found that the maximum swelling percent was 5000 % for the CMC/PAM hydrogel, 12000 % for the CMC/PAM/Si composite hydrogel, and 6200 % for the CMC/PVA hydrogel. The gel fraction, equilibrium swelling and effect of ph on the swelling percent were also studied. The prepared copolymers were also characterized by FTIR spectral analysis, thermo gravimetric analysis (TGA), and scanning electron microscopy (SEM) techniques. In order to evaluate its controlled release potential, different prepared hydrogels were loaded with KNO 3 as an agrochemical model and its potential for controlled release of KNO 3 was studied and evaluated with respect to different parameters such as time of release, ph of the medium, and temperatures. The results obtained from swelling, loading of KNO 3 , and release behavior studies suggested and recommended the possible use of prepared hydrogels for enhancing the plantation of Linum Usitatissimum.

  16. Thermo-responsive methylcellulose hydrogels as temporary substrate for cell sheet biofabrication.

    Science.gov (United States)

    Altomare, Lina; Cochis, Andrea; Carletta, Andrea; Rimondini, Lia; Farè, Silvia

    2016-05-01

    Methylcellulose (MC), a water-soluble polymer derived from cellulose, was investigated as a possible temporary substrate having thermo-responsive properties favorable for cell culturing. MC-based hydrogels were prepared by a dispersion technique, mixing MC powder (2, 4, 6, 8, 10, 12 % w/v) with selected salts (sodium sulphate, Na2SO4), sodium phosphate, calcium chloride, or phosphate buffered saline, to evaluate the influence of different compositions on the thermo-responsive behavior. The inversion test was used to determine the gelation temperatures of the different hydrogel compositions; thermo-mechanical properties and thermo-reversibility of the MC hydrogels were investigated by rheological analysis. Gelation temperatures and rheological behavior depended on the MC concentration and type and concentration of salt used in hydrogel preparation. In vitro cytotoxicity tests, performed using L929 mouse fibroblasts, showed no toxic release from all the tested hydrogels. Among the investigated compositions, the hydrogel composed of 8 % w/v MC with 0.05 M Na2SO4 had a thermo-reversibility temperature at 37 °C. For that reason, this formulation was thus considered to verify the possibility of inducing in vitro spontaneous detachment of cells previously seeded on the hydrogel surface. A continuous cell layer (cell sheet) was allowed to grow and then detached from the hydrogel surface without the use of enzymes, thanks to the thermo-responsive behavior of the MC hydrogel. Immunofluorescence observation confirmed that the detached cell sheet was composed of closely interacting cells.

  17. Cell-laden hydrogels for osteochondral and cartilage tissue engineering.

    Science.gov (United States)

    Yang, Jingzhou; Zhang, Yu Shrike; Yue, Kan; Khademhosseini, Ali

    2017-07-15

    Despite tremendous advances in the field of regenerative medicine, it still remains challenging to repair the osteochondral interface and full-thickness articular cartilage defects. This inefficiency largely originates from the lack of appropriate tissue-engineered artificial matrices that can replace the damaged regions and promote tissue regeneration. Hydrogels are emerging as a promising class of biomaterials for both soft and hard tissue regeneration. Many critical properties of hydrogels, such as mechanical stiffness, elasticity, water content, bioactivity, and degradation, can be rationally designed and conveniently tuned by proper selection of the material and chemistry. Particularly, advances in the development of cell-laden hydrogels have opened up new possibilities for cell therapy. In this article, we describe the problems encountered in this field and review recent progress in designing cell-hydrogel hybrid constructs for promoting the reestablishment of osteochondral/cartilage tissues. Our focus centers on the effects of hydrogel type, cell type, and growth factor delivery on achieving efficient chondrogenesis and osteogenesis. We give our perspective on developing next-generation matrices with improved physical and biological properties for osteochondral/cartilage tissue engineering. We also highlight recent advances in biomanufacturing technologies (e.g. molding, bioprinting, and assembly) for fabrication of hydrogel-based osteochondral and cartilage constructs with complex compositions and microarchitectures to mimic their native counterparts. Despite tremendous advances in the field of regenerative medicine, it still remains challenging to repair the osteochondral interface and full-thickness articular cartilage defects. This inefficiency largely originates from the lack of appropriate tissue-engineered biomaterials that replace the damaged regions and promote tissue regeneration. Cell-laden hydrogel systems have emerged as a promising tissue

  18. Radiation synthesis of superabsorbent polyethylene oxide/tragacanth hydrogel

    Science.gov (United States)

    Khoylou, F.; Naimian, F.

    2009-03-01

    A new superabsorbent hydrogel has been prepared from tragacanth and polyethylene oxide (PEO) by gamma radiation at room temperature. Tragacanth solutions with different concentrations (1%, 3% and 5%) have been blended with 5% aqueous solution of PEO at a ratio of 1:1 and irradiated at doses 5-20 kGy. The properties of the prepared composite hydrogels were evaluated in terms of the gel fraction and the swelling behavior. An unexpected growth of the gel fraction was observed in PEO/tragacanth hydrogels irradiated at 5 kGy. Incorporation of 5% tragacanth into the aqueous PEO increased significantly the swelling percent of the hydrogels to more than 14,000% and thus makes it a superabsorbent material.

  19. Radiation synthesis of superabsorbent polyethylene oxide/tragacanth hydrogel

    Energy Technology Data Exchange (ETDEWEB)

    Khoylou, F. [Nuclear Science and Technology Research Institute, Radiation Applications Research School, P.O. Box 11365-3486, Tehran (Iran, Islamic Republic of)], E-mail: fkhoylou@aeoi.org.ir; Naimian, F. [Nuclear Science and Technology Research Institute, Radiation Applications Research School, P.O. Box 11365-3486, Tehran (Iran, Islamic Republic of)

    2009-03-15

    A new superabsorbent hydrogel has been prepared from tragacanth and polyethylene oxide (PEO) by gamma radiation at room temperature. Tragacanth solutions with different concentrations (1%, 3% and 5%) have been blended with 5% aqueous solution of PEO at a ratio of 1:1 and irradiated at doses 5-20 kGy. The properties of the prepared composite hydrogels were evaluated in terms of the gel fraction and the swelling behavior. An unexpected growth of the gel fraction was observed in PEO/tragacanth hydrogels irradiated at 5 kGy. Incorporation of 5% tragacanth into the aqueous PEO increased significantly the swelling percent of the hydrogels to more than 14,000% and thus makes it a superabsorbent material.

  20. Radiation synthesis of superabsorbent polyethylene oxide/tragacanth hydrogel

    International Nuclear Information System (INIS)

    Khoylou, F.; Naimian, F.

    2009-01-01

    A new superabsorbent hydrogel has been prepared from tragacanth and polyethylene oxide (PEO) by gamma radiation at room temperature. Tragacanth solutions with different concentrations (1%, 3% and 5%) have been blended with 5% aqueous solution of PEO at a ratio of 1:1 and irradiated at doses 5-20 kGy. The properties of the prepared composite hydrogels were evaluated in terms of the gel fraction and the swelling behavior. An unexpected growth of the gel fraction was observed in PEO/tragacanth hydrogels irradiated at 5 kGy. Incorporation of 5% tragacanth into the aqueous PEO increased significantly the swelling percent of the hydrogels to more than 14,000% and thus makes it a superabsorbent material

  1. Radiation synthesis of superabsorbent CMC based hydrogels for agriculture applications

    International Nuclear Information System (INIS)

    Raafat, Amany I.; Eid, Mona; El-Arnaouty, Magda B.

    2012-01-01

    A series of superabsorbent hydrogel based on carboxymethylcellulose (CMC) and polyvinylpyrrolidone (PVP) crosslinked with gamma irradiation have been proposed for agriculture application. The effect of preparation conditions such as feed solution composition and absorbed irradiation dose on the gelation and swelling degree was evaluated. The structure and the morphology of the superabsorbent CMC/PVP hydrogel were characterized using Fourier transform infrared spectroscopy technique (FTIR), and scanning electron microscope (SEM). Effect of ionic strength and cationic and anionic kinds on the swelling behavior of the obtained hydrogel was investigated. Urea as an agrochemical model was loaded onto the obtained hydrogel to provide nitrogen (N) nutrients. The water retention capability and the urea release behavior of the CMC/PVP hydrogels were investigated. It was found that, the obtained CMC/PVP hydrogels have good swelling degree that greatly affected by its composition and absorbed dose. The swelling was also extremely sensitive to the ionic strength and cationic kind. Owing to its considerable slow urea release, good water retention capacity, being economical, and environment-friendly, it might be useful for its application in agriculture field.

  2. Radiation synthesis of superabsorbent CMC based hydrogels for agriculture applications

    Science.gov (United States)

    Raafat, Amany I.; Eid, Mona; El-Arnaouty, Magda B.

    2012-07-01

    A series of superabsorbent hydrogel based on carboxymethylcellulose (CMC) and polyvinylpyrrolidone (PVP) crosslinked with gamma irradiation have been proposed for agriculture application. The effect of preparation conditions such as feed solution composition and absorbed irradiation dose on the gelation and swelling degree was evaluated. The structure and the morphology of the superabsorbent CMC/PVP hydrogel were characterized using Fourier transform infrared spectroscopy technique (FTIR), and scanning electron microscope (SEM). Effect of ionic strength and cationic and anionic kinds on the swelling behavior of the obtained hydrogel was investigated. Urea as an agrochemical model was loaded onto the obtained hydrogel to provide nitrogen (N) nutrients. The water retention capability and the urea release behavior of the CMC/PVP hydrogels were investigated. It was found that, the obtained CMC/PVP hydrogels have good swelling degree that greatly affected by its composition and absorbed dose. The swelling was also extremely sensitive to the ionic strength and cationic kind. Owing to its considerable slow urea release, good water retention capacity, being economical, and environment-friendly, it might be useful for its application in agriculture field.

  3. Radiation synthesis of superabsorbent CMC based hydrogels for agriculture applications

    Energy Technology Data Exchange (ETDEWEB)

    Raafat, Amany I., E-mail: ismaelraafat_a@hotmail.com [Polymer Chemistry Department, National Center for Radiation Research and Technology, P.O. Box 29, Nasr City, Cairo (Egypt); Eid, Mona; El-Arnaouty, Magda B. [Polymer Chemistry Department, National Center for Radiation Research and Technology, P.O. Box 29, Nasr City, Cairo (Egypt)

    2012-07-15

    A series of superabsorbent hydrogel based on carboxymethylcellulose (CMC) and polyvinylpyrrolidone (PVP) crosslinked with gamma irradiation have been proposed for agriculture application. The effect of preparation conditions such as feed solution composition and absorbed irradiation dose on the gelation and swelling degree was evaluated. The structure and the morphology of the superabsorbent CMC/PVP hydrogel were characterized using Fourier transform infrared spectroscopy technique (FTIR), and scanning electron microscope (SEM). Effect of ionic strength and cationic and anionic kinds on the swelling behavior of the obtained hydrogel was investigated. Urea as an agrochemical model was loaded onto the obtained hydrogel to provide nitrogen (N) nutrients. The water retention capability and the urea release behavior of the CMC/PVP hydrogels were investigated. It was found that, the obtained CMC/PVP hydrogels have good swelling degree that greatly affected by its composition and absorbed dose. The swelling was also extremely sensitive to the ionic strength and cationic kind. Owing to its considerable slow urea release, good water retention capacity, being economical, and environment-friendly, it might be useful for its application in agriculture field.

  4. Improved Concrete Materials with Hydrogel-Based Internal Curing Agents

    Directory of Open Access Journals (Sweden)

    Matthew J. Krafcik

    2017-11-01

    Full Text Available This research article will describe the design and use of polyelectrolyte hydrogel particles as internal curing agents in concrete and present new results on relevant hydrogel-ion interactions. When incorporated into concrete, hydrogel particles release their stored water to fuel the curing reaction, resulting in reduced volumetric shrinkage and cracking and thus increasing concrete service life. The hydrogel’s swelling performance and mechanical properties are strongly sensitive to multivalent cations that are naturally present in concrete mixtures, including calcium and aluminum. Model poly(acrylic acid(AA-acrylamide(AM-based hydrogel particles with different chemical compositions (AA:AM monomer ratio were synthesized and immersed in sodium, calcium, and aluminum salt solutions. The presence of multivalent cations resulted in decreased swelling capacity and altered swelling kinetics to the point where some hydrogel compositions displayed rapid deswelling behavior and the formation of a mechanically stiff shell. Interestingly, when incorporated into mortar, hydrogel particles reduced mixture shrinkage while encouraging the formation of specific inorganic phases (calcium hydroxide and calcium silicate hydrate within the void space previously occupied by the swollen particle.

  5. MWCNTs/Cellulose Hydrogels Prepared from NaOH/Urea Aqueous Solution with Improved Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Yingpu Zhang

    2015-01-01

    Full Text Available Novel high strength composite hydrogels were designed and synthesized by introducing multiwalled carbon nanotubes (MWCNTs into cellulose/NaOH/urea aqueous solution and then cross-linked by epichlorohydrin. MWCNTs were used to modify the matrix of cellulose. The structure and morphology of the hydrogels were characterized by Fourier transform infrared (FT-IR spectroscopy, high resolution transmission electron microscopy (HR-TEM, and scanning electron microscopy (SEM. The results from swelling testing revealed that the equilibrium swelling ratio of hydrogels decreased with the increment of MWCNTs content. Thermogravimetric analysis (TGA and dynamic mechanical analysis (DMA results demonstrated that the introduction of MWCNT into cellulose hydrogel networks remarkably improved both thermal and mechanical properties of the composite hydrogels. The preparation of MWCNTs modifiedcellulose-based composites with improved mechanical properties was the first important step towards the development of advanced functional materials.

  6. Cellulose fibers extracted from rice and oat husks and their application in hydrogel.

    Science.gov (United States)

    Oliveira, Jean Paulo de; Bruni, Graziella Pinheiro; Lima, Karina Oliveira; Halal, Shanise Lisie Mello El; Rosa, Gabriela Silveira da; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa

    2017-04-15

    The commercial cellulose fibers and cellulose fibers extracted from rice and oat husks were analyzed by chemical composition, morphology, functional groups, crystallinity and thermal properties. The cellulose fibers from rice and oat husks were used to produce hydrogels with poly (vinyl alcohol). The fibers presented different structural, crystallinity, and thermal properties, depending on the cellulose source. The hydrogel from rice cellulose fibers had a network structure with a similar agglomeration sponge, with more homogeneous pores compared to the hydrogel from oat cellulose fibers. The hydrogels prepared from the cellulose extracted from rice and oat husks showed water absorption capacity of 141.6-392.1% and high opacity. The highest water absorption capacity and maximum stress the compression were presented by rice cellulose hydrogel at 25°C. These results show that the use of agro-industrial residues is promising for the biomaterial field, especially in the preparation of hydrogels. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Biodestruction of strongly swelling polymer hydrogels and its effect on the water retention capacity of soils

    Science.gov (United States)

    Smagin, A. V.; Sadovnikova, N. B.; Smagina, M. V.

    2014-06-01

    The biodestruction of strongly swelling polymer hydrogels (water adsorbing soil conditioners of the new generation) has been studied at the quantitative level using original mathematical models. In laboratory experiments, a relationship between the hydrogel degradation rate and the temperature has been obtained, and the effect of the biodestruction on the water retention curve of soil compositions with hydrogels (used as an index of their water retention capacity) has been assessed. From the automatic monitoring data of the temperature regime of soils, the potential biodestruction of hydrogels has been predicted for different climatic conditions. The loss of hydrogels during three months of the vegetation period because of destruction can exceed 30% of their initial content in irrigated agriculture under arid climatic conditions and more than 10% under humid climatic conditions. Thus, the biodestruction of hydrogels is one of the most important factors decreasing their efficiency under actual soil conditions.

  8. Chitosan-dextran sulfate hydrogels as a potential carrier for probiotics

    DEFF Research Database (Denmark)

    Yucel Falco, Cigdem; Falkman, Peter; Risbo, Jens

    2017-01-01

    Physical and chemical (crosslinked with genipin) hydrogels based on chitosan and dextran sulfate were developed and characterized as novel bio-materials suitable for probiotic encapsulation. The swelling of the hydrogels was dependent on the composition and weakly influenced by the pH of the media...

  9. Biomedical hydrogels biochemistry, manufacture and medical applications

    CERN Document Server

    Rimmer, Steve

    2011-01-01

    Hydrogels are very important for biomedical applications because they can be chemically manipulated to alter and control the hydrogel's interaction with cells and tissues. Their flexibility and high water content is similar to that of natural tissue, making them extremely suitable for biomaterials applications. Biomedical hydrogels explores the diverse range and use of hydrogels, focusing on processing methods and novel applications in the field of implants and prostheses. Part one of this book concentrates on the processing of hydrogels, covering hydrogel swelling behaviour, superabsorbent cellulose-based hydrogels and regulation of novel hydrogel products, as well as chapters focusing on the structure and properties of hydrogels and different fabrication technologies. Part two covers existing and novel applications of hydrogels, including chapters on spinal disc and cartilage replacement implants, hydrogels for ophthalmic prostheses and hydrogels for wound healing applications. The role of hydrogels in imag...

  10. Rheological investigation of high-acyl gellan gum hydrogel and its mixtures with simulated body fluids.

    Science.gov (United States)

    Osmałek, Tomasz Zbigniew; Froelich, Anna; Jadach, Barbara; Krakowski, Marek

    2018-05-01

    Purpose Most of the studies concerning gellan have been focused on its application as a food ingredient, however, gellan is often considered as a candidate for the development of novel pharmaceutical formulations. Taking into account that gellan is ion-sensitive, it can be assumed that its initial mechanical properties can change upon contact with body secretions. Therefore, the aim of the work was to investigate the rheological properties of pure high-acyl gellan gum hydrogel (0.4%) and its mixtures with selected simulated body fluids. Methods The rheological investigations were performed on rotational rheometer and included oscillatory temperature, amplitude, and frequency sweeping. The results enabled estimation of the linear viscoelastic regime, calculation of the cross-over points, and percentage of structure recovery. Results In the case of pure hydrogel no evidence of thermosensitivity was observed in the range of 20-40°C. In pH = 1.2 (NaCl/HCl) the hydrogel structure was almost entirely destroyed. Mixing with phosphate buffer (pH = 4.5) resulted in higher gel strength than after dilution with deionized water. The opposite effect was observed in the case of pH = 7.4. The studies performed for the mixture of GG hydrogel and mucin indicated interaction between the components. The hydrogel elasticity increased in the presence of simulated tear, but decreased in simulated saliva and vaginal fluid. Conclusions In this study, it was shown that the stability of a three-dimensional gellan structure may be affected by pH and the presence of mucin which most probably competed with gellan gum in divalent cations binding. The observations presented in this study may be important in terms of potential application of gellan gum as a potential carrier in drug delivery systems.

  11. The influence of increased cross-linker chain length in thermosensitive microspheres on potential sun-protection activity

    OpenAIRE

    Musiał, Witold; Kokol, Vanja; Vončina, Bojana

    2012-01-01

    The sun protection should involve substances with protecting activity against both UVB and UVA radiation. In this research the evaluation of thermosensitive microspheres as potential molecules for sunscreen formulations was approached, using modified Boots star rating system. The microspheres, thermosensitive N-isopropylacrylamide derivatives, have potential protecting activity against UV radiation. The MX and DX microspheres, with ethylene glycol dimethacrylate and diethylene glycol dimethac...

  12. Adipose-derived stem cells seeded in Pluronic F-127 hydrogel promotes diabetic wound healing.

    Science.gov (United States)

    Kaisang, Lin; Siyu, Wang; Lijun, Fan; Daoyan, Pan; Xian, Cory J; Jie, Shen

    2017-09-01

    Chronic nonhealing wound is a multifactorial complication of diabetes that results specifically as a consequence of impaired angiogenesis and currently lacks in effective treatments. Although a stem cell-based therapy may provide a novel treatment to augment diabetic wound healing, inferior cell survival at the diabetic skin wound is one of the key causes that are responsible for the low efficacy of the stem cell therapy. In this work, we used an injectable, biocompatible, and thermosensitive hydrogel Pluronic F-127 to encapsulate allogeneic nondiabetic adipose-derived stem cells (ADSCs) and topically applied the cells to a full-thickness cutaneous wound in the streptozotocin-induced diabetic model in rats. The cells seeded in the hydrogel enhanced angiogenesis (CD31 marker) and promoted the cell proliferation (Ki67 marker) at the wound site and significantly accelerated wound closure, which was accompanied by facilitated regeneration of granulation tissue. Consistently, levels of the messenger RNA expression of key angiogenesis growth factor, vascular endothelial growth factor, and key wound healing growth factor, transforming growth factor beta 1, were also upregulated in the cell-treated wounds when compared with untreated wounds. The results indicated that the transplantation of allogeneic ADSCs via the hydrogel improves the efficiency of cell delivery and optimizes the performance of ADSCs for augmenting diabetic wound healing. In conclusion, this ADSC-based therapy may provide a novel therapeutic strategy for the treatment of nonhealing diabetic foot ulcers. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Radiation Synthesis of Super absorbent CMC Based Hydrogels For Agriculture Applications

    International Nuclear Information System (INIS)

    Raafat, A.I.; Eid, M.; El-Arnaouty, M.B.

    2010-01-01

    A good hydrogels of carboxy methyl cellulose (CMC) and poly vinyl pyrrolidone (PVP) were synthesized by gamma radiation at different doses and compositions. The prepared hydrogels were characterized by (FTIR) and (SEM). The hydrogels properties such as gelation (%), swelling and water retention capability were investigated. As the content of PVP in PVP/CMC hydrogels increased the gelation (%) increased. The swelling ratio of prepared hydrogel decreased with increasing of irradiation doses and the temperature. The (PVP/CMC) hydrogen of composition (40:60) prepared at 20 kGy showed the highest swelling ratio. The addition of sodium bicarbonate (NaHCO 3 ) to the PVP/CMC hydrogels during the irradiation process decreases the swelling ratio. The water retention reveals a similar behavior for the different compositions. The swelling characteristics in the presence of different cations and anions in a swelling medium were studied. The hydrogels were also loaded with urea solutions as a model agrochemical and their potential application for controlled release has been investigated. The improve properties of the prepared materials suggested that, the (PVP/CMC) hydrogels can be use in agriculture applications

  14. High performances of dual network PVA hydrogel modified by PVP using borax as the structure-forming accelerator.

    Science.gov (United States)

    Huang, Min; Hou, Yi; Li, Yubao; Wang, Danqing; Zhang, Li

    2017-01-01

    A dual network hydrogel made up of polyvinylalcohol (PVA) crosslinked by borax and polyvinylpyrrolidone (PVP) was prepared by means of freezing-thawing circles. Here PVP was incorporated by linking with PVA to form a network structure, while the introduction of borax played the role of crosslinking PVA chains to accelerate the formation of a dual network structure in PVA/PVP composite hydrogel, thus endowing the hydrogel with high mechanical properties. The effects of both PVP and borax on the hydrogels were evaluated by comparing the two systems of PVA/PVP/borax and PVA/borax hydrogels. In the former system, adding 4.0% PVP not only increased the water content and the storage modulus but also enhanced the mechanical strength of the final hydrogel. But an overdose of PVP just as more than 4.0% tended to undermine the structure of hydrogels, and thus deteriorated hydrogels' properties because of the weakened secondary interaction between PVP and PVA. Likewise, increasing borax could promote the gel crosslinking degree, thus making gels show a decrease in water content and swelling ratio, meanwhile shrinking the pores inside the hydrogels and finally enhancing the mechanical strength of hydrogels prominently. The developed hydrogel with high performances holds great potential for applications in biomedical and industrial fields.

  15. Recent advances in clay mineral-containing nanocomposite hydrogels.

    Science.gov (United States)

    Zhao, Li Zhi; Zhou, Chun Hui; Wang, Jing; Tong, Dong Shen; Yu, Wei Hua; Wang, Hao

    2015-12-28

    Clay mineral-containing nanocomposite hydrogels have been proven to have exceptional composition, properties, and applications, and consequently have attracted a significant amount of research effort over the past few years. The objective of this paper is to summarize and evaluate scientific advances in clay mineral-containing nanocomposite hydrogels in terms of their specific preparation, formation mechanisms, properties, and applications, and to identify the prevailing challenges and future directions in the field. The state-of-the-art of existing technologies and insights into the exfoliation of layered clay minerals, in particular montmorillonite and LAPONITE®, are discussed first. The formation and structural characteristics of polymer/clay nanocomposite hydrogels made from in situ free radical polymerization, supramolecular assembly, and freezing-thawing cycles are then examined. Studies indicate that additional hydrogen bonding, electrostatic interactions, coordination bonds, hydrophobic interaction, and even covalent bonds could occur between the clay mineral nanoplatelets and polymer chains, thereby leading to the formation of unique three-dimensional networks. Accordingly, the hydrogels exhibit exceptional optical and mechanical properties, swelling-deswelling behavior, and stimuli-responsiveness, reflecting the remarkable effects of clay minerals. With the pivotal roles of clay minerals in clay mineral-containing nanocomposite hydrogels, the nanocomposite hydrogels possess great potential as superabsorbents, drug vehicles, tissue scaffolds, wound dressing, and biosensors. Future studies should lay emphasis on the formation mechanisms with in-depth insights into interfacial interactions, the tactical functionalization of clay minerals and polymers for desired properties, and expanding of their applications.

  16. Protein diffusion in photopolymerized poly(ethylene glycol) hydrogel networks

    International Nuclear Information System (INIS)

    Engberg, Kristin; Frank, Curtis W

    2011-01-01

    In this study, protein diffusion through swollen hydrogel networks prepared from end-linked poly(ethylene glycol)-diacrylate (PEG-DA) was investigated. Hydrogels were prepared via photopolymerization from PEG-DA macromonomer solutions of two molecular weights, 4600 Da and 8000 Da, with three initial solid contents: 20, 33 and 50 wt/wt% PEG. Diffusion coefficients for myoglobin traveling across the hydrogel membrane were determined for all PEG network compositions. The diffusion coefficient depended on PEG molecular weight and initial solid content, with the slowest diffusion occurring through lower molecular weight, high-solid-content networks (D gel = 0.16 ± 0.02 x 10 -8 cm 2 s -1 ) and the fastest diffusion occurring through higher molecular weight, low-solid-content networks (D gel = 11.05 ± 0.43 x 10 -8 cm 2 s -1 ). Myoglobin diffusion coefficients increased linearly with the increase of water content within the hydrogels. The permeability of three larger model proteins (horseradish peroxidase, bovine serum albumin and immunoglobulin G) through PEG(8000) hydrogel membranes was also examined, with the observation that globular molecules as large as 10.7 nm in hydrodynamic diameter can diffuse through the PEG network. Protein diffusion coefficients within the PEG hydrogels ranged from one to two orders of magnitude lower than the diffusion coefficients in free water. Network defects were determined to be a significant contributing factor to the observed protein diffusion.

  17. Automation of 3D cell culture using chemically defined hydrogels.

    Science.gov (United States)

    Rimann, Markus; Angres, Brigitte; Patocchi-Tenzer, Isabel; Braum, Susanne; Graf-Hausner, Ursula

    2014-04-01

    Drug development relies on high-throughput screening involving cell-based assays. Most of the assays are still based on cells grown in monolayer rather than in three-dimensional (3D) formats, although cells behave more in vivo-like in 3D. To exemplify the adoption of 3D techniques in drug development, this project investigated the automation of a hydrogel-based 3D cell culture system using a liquid-handling robot. The hydrogel technology used offers high flexibility of gel design due to a modular composition of a polymer network and bioactive components. The cell inert degradation of the gel at the end of the culture period guaranteed the harmless isolation of live cells for further downstream processing. Human colon carcinoma cells HCT-116 were encapsulated and grown in these dextran-based hydrogels, thereby forming 3D multicellular spheroids. Viability and DNA content of the cells were shown to be similar in automated and manually produced hydrogels. Furthermore, cell treatment with toxic Taxol concentrations (100 nM) had the same effect on HCT-116 cell viability in manually and automated hydrogel preparations. Finally, a fully automated dose-response curve with the reference compound Taxol showed the potential of this hydrogel-based 3D cell culture system in advanced drug development.

  18. [The appraisal of mechanical properties and friction coefficient of PVA hydro-gel].

    Science.gov (United States)

    Chen, Liqi; Zhang, Dekun; Zhang, Jinsong

    2009-10-01

    Gelatin and hydroxyapatite were introduced to polyvinyl alcohol (PVA) hydrogel with an attempt to enhance the performances of PVA hydrogel. Through a reiterative freezing-thawing methods, three kinds of PVA composite hydrogels were prepared. The mechanical performances of these composite hydrogels with the same PVA and HA content but varying gelatin content, such as tensile strength, elasticity modulus, creep curve, relaxation curve and friction coefficient were evaluated by using a computer-controlled universal electronic mechanical testing machine and a UMT-II frictional testing machine. The additional effects of hydroxylapatite and varying gelatin on the performances of composite PVA hydro-gels were analyzed. It was found that the gelatin content directly influenced the physical performances of PVA composite hydrogels; but no linear relationship was recorded. PVA composite hydrogel containing 2wt-% gelatin gave optimal results, i.e. tensile strength of 5.5MPa, compressive elastical modulus of 1.48MPa, creeping rate of 31% in 45 minutes, stress relaxing rate of 40.3%, and the starting friction coefficient of 0.332.

  19. Fibre-reinforced hydrogels for tissue engineering

    Science.gov (United States)

    Waters, Sarah; Byrne, Helen; Chen, Mike; Dias Castilho, Miguel; Kimpton, Laura; Please, Colin; Whiteley, Jonathan

    2017-11-01

    Tissue engineers aim to grow replacement tissues in vitro to replace those in the body that have been damaged through age, trauma or disease. One approach is to seed cells within a scaffold consisting of an interconnected 3D-printed lattice of polymer fibres, cast in a hydrogel, and subject the construct (cell-seeded scaffold) to an applied load in a bioreactor. A key question is to understand how this applied load is distributed throughout the construct to the mechanosensitive cells. To address this, we exploit the disparate length scales (small inter-fibre spacing compared with construct dimensions). The fibres are treated as a linear elastic material and the hydrogel as a poroelastic material. We employ homogenisation theory to derive equations governing the material properties of a periodic, elastic-poroelastic composite. To validate the mobel, model solutions are compared to experimental data describing the unconfined compression of the fibre-reinforced hydrogels. The model is used to derive the bulk mechanical properties of a cylindrical construct of the composite material for a range of fibre spacings, and the local mechanical environment experienced by cells embedded within the construct is determined. Funded by the European Union Seventh Framework Programme (FP7/2007-2013).

  20. Carbon Nanotubes Reinforced Maleic Anhydride-Modified Xylan-g-Poly(N-isopropylacrylamide) Hydrogel with Multifunctional Properties

    Science.gov (United States)

    Liu, Xinxin; Song, Tao; Chang, Minmin; Meng, Ling; Wang, Xiaohui; Sun, Runcang; Ren, Junli

    2018-01-01

    Introducing multifunctional groups and inorganic material imparts xylan-based hydrogels with excellent properties, such as responsiveness to pH, temperature, light, and external magnetic field. In this work, a composite hydrogel was synthesized by introducing acid treated carbon nanotubes (AT-CNTs) into the maleic anhydride modified xylan grafted with poly(N-isopropylacrylamide) (MAX-g-PNIPAM) hydrogels network. It was found that the addition of AT-CNTs affected the MAX-g-PNIPAM hydrogel structure, the swelling ratio and mechanical properties, and imparted the hydrogel with new properties of electrical conductivity and near infrared region (NIR) photothermal conversion. AT-CNTs could reinforce the mechanical properties of MAX-g-PNIPAM hydrogels, being up to 83 kPa for the compressive strength when the amount was 11 wt %, which was eight times than that of PNIPAM hydrogel and four times than that of MAX-g-PNIPAM hydrogel. The electroconductibility was enhanced by the increase of AT-CNTs amounts. Meanwhile, the composite hydrogel also exhibited multiple shape memory and NIR photothermal conversion properties, and water temperature was increased from 26 °C to 56 °C within 8 min under the NIR irradiation. Thus, the AT-CNTs reinforced MAX-g-PNIPAM hydrogel possessed promising multifunctional properties, which offered many potential applications in the fields of biosensors, thermal-arrest technology, and drug-controlled release. PMID:29495611

  1. Bioinspired Hydrogels to Engineer Cancer Microenvironments.

    Science.gov (United States)

    Park, Kyung Min; Lewis, Daniel; Gerecht, Sharon

    2017-06-21

    Recent research has demonstrated that tumor microenvironments play pivotal roles in tumor development and metastasis through various physical, chemical, and biological factors, including extracellular matrix (ECM) composition, matrix remodeling, oxygen tension, pH, cytokines, and matrix stiffness. An emerging trend in cancer research involves the creation of engineered three-dimensional tumor models using bioinspired hydrogels that accurately recapitulate the native tumor microenvironment. With recent advances in materials engineering, many researchers are developing engineered tumor models, which are promising platforms for the study of cancer biology and for screening of therapeutic agents for better clinical outcomes. In this review, we discuss the development and use of polymeric hydrogel materials to engineer native tumor ECMs for cancer research, focusing on emerging technologies in cancer engineering that aim to accelerate clinical outcomes.

  2. Design and synthesis of an amphiphilic graft hydrogel having a hydrophobic domain formed by multiple interactions

    Energy Technology Data Exchange (ETDEWEB)

    Nitta, Kyohei [Department of Life and Functional Material Science, Graduate School of Natural Science, Konan University, 8-9-1 Okamoto, Higashinada, Kobe 658-8501 (Japan); Japan Society for the Promotion of Science (DC1), Ichibancho, Chiyoda, Tokyo 102-8471 (Japan); Kimoto, Atsushi [Department of Chemistry of Functional Molecules, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Higashinada, Kobe 658-8501 (Japan); Watanabe, Junji, E-mail: junjiknd@konan-u.ac.jp [Department of Chemistry of Functional Molecules, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Higashinada, Kobe 658-8501 (Japan)

    2016-11-01

    A novel hydrogel having hydrophobic oligo segments and hydrophilic poly(acrylamidoglycolic acid) (PAGA) as pH responsive polymer segments was designed and synthesized to be used as a soft biomaterial. Poly(trimethylene carbonate) (PTMC) as the side chain, for which the degrees of polymerization were 9, 19, and 49, and the composition ratios were 1, 5, and 10 mol%, was used as the oligo segment in the hydrogel. The swelling ratio of the hydrogel was investigated under various changes in conditions such as pH, temperature, and hydrogen bonding upon urea addition. Under pH 2–11 conditions, the graft gel reversibly swelled and shrank due to the effect of PAGA main chain. The interior morphology and skin layer of the hydrogel was observed by a scanning electron microscope. The hydrogel composed of PAGA as the hydrophilic polymer backbone had a sponge-like structure, with a pore size of approximately 100 μm. On the other hand, upon increasing the ratio of trimethylene carbonate (TMC) units in the hydrogel, the pores became smaller or disappeared. Moreover, thickness of the skin layer significantly increased with the swelling ratio depended on the incorporation ratios of the PTMC macromonomer. Molecular incorporation in the hydrogel was evaluated using a dye as a model drug molecule. These features would play an important role in drug loading. Increasing the ratio of TMC units favored the adsorption of the dye and activation of the incorporation behavior. - Highlights: • Hydrogen bonding and hydrophobic interaction are dominant factor for forming hydrogels. • Hydrogel properties were tuned by changing in graft length and macromonomer content in feed. • The resulting graft gel could encapsulate and retain organic dye in the hydrogel. • Poly(trimethylene carbonate) segment in the hydrogel was dominant unit for hydrogel.

  3. Design and synthesis of an amphiphilic graft hydrogel having a hydrophobic domain formed by multiple interactions

    International Nuclear Information System (INIS)

    Nitta, Kyohei; Kimoto, Atsushi; Watanabe, Junji

    2016-01-01

    A novel hydrogel having hydrophobic oligo segments and hydrophilic poly(acrylamidoglycolic acid) (PAGA) as pH responsive polymer segments was designed and synthesized to be used as a soft biomaterial. Poly(trimethylene carbonate) (PTMC) as the side chain, for which the degrees of polymerization were 9, 19, and 49, and the composition ratios were 1, 5, and 10 mol%, was used as the oligo segment in the hydrogel. The swelling ratio of the hydrogel was investigated under various changes in conditions such as pH, temperature, and hydrogen bonding upon urea addition. Under pH 2–11 conditions, the graft gel reversibly swelled and shrank due to the effect of PAGA main chain. The interior morphology and skin layer of the hydrogel was observed by a scanning electron microscope. The hydrogel composed of PAGA as the hydrophilic polymer backbone had a sponge-like structure, with a pore size of approximately 100 μm. On the other hand, upon increasing the ratio of trimethylene carbonate (TMC) units in the hydrogel, the pores became smaller or disappeared. Moreover, thickness of the skin layer significantly increased with the swelling ratio depended on the incorporation ratios of the PTMC macromonomer. Molecular incorporation in the hydrogel was evaluated using a dye as a model drug molecule. These features would play an important role in drug loading. Increasing the ratio of TMC units favored the adsorption of the dye and activation of the incorporation behavior. - Highlights: • Hydrogen bonding and hydrophobic interaction are dominant factor for forming hydrogels. • Hydrogel properties were tuned by changing in graft length and macromonomer content in feed. • The resulting graft gel could encapsulate and retain organic dye in the hydrogel. • Poly(trimethylene carbonate) segment in the hydrogel was dominant unit for hydrogel.

  4. Synthesis composite hydrogels from inorganic-organic hybrids based on leftover rice for environment-friendly controlled-release urea fertilizers.

    Science.gov (United States)

    Zhou, Tao; Wang, Yan; Huang, Sheng; Zhao, Youcai

    2018-02-15

    Nearly 1.3 billion tons of food are discarded annually in the production process. In this study, a novel slow-release nitrogen fertilizer with water absorbency was developed using leftover rice and crosslinking methods. Urea was incorporated as the nitrogen source in a leftover rice-g-poly(acrylic acid)/montmorillonite (LR-g-PAA/MMT) network, and then the leftover rice-g-poly(acrylic acid)/montmorillonite/Urea (LR-g-PAA/MMT/Urea) retained in the soil, and used as the loss control agent for water and nutrients. Variables including concentrations of acrylic acid, montmorillonite, N,N´-methylenebis acrylamide (MBA), and potassium persulfate (KPS) were investigated. Samples were with a water absorbency of 102.6g/g in distilled water and 25.1g/g in 1.0wt% NaCl solution under optimized conditions. Swelling measurements and water-retention indicated that higher-covalent cations would aggregate the hydrogels and decrease swelling. Investigating leaching behavior showed that these samples have the potential to carry the necessary nitrogen (N). The results demonstrated that the LR-g-PAA/MMT/Urea had a low leaching losses of N (19.7%) compared with pure urea (52.3%). Therefore, the developed fertilizer may be widely applicable in agriculture and horticulture, and could provide a new platform for reusing leftover rice. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    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.

  6. Synthesis of thermosensitive magnetic nanocarrier for controlled sorafenib delivery

    Energy Technology Data Exchange (ETDEWEB)

    Heidarinasab, Amir [Department of Chemical Engineering, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Ahmad Panahi, Homayon [Department of Chemistry, Central Tehran Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Faramarzi, Mehdi, E-mail: faramarzi.iaug@gmail.com [Department of Chemical Engineering, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Farjadian, Fatemeh [Pharmaceutical Sciences Research Center, Faculty of Pharmacy, Shiraz University of Medical Sciences, Shiraz (Iran, Islamic Republic of)

    2016-10-01

    Allyl glycidyl ether/N-isopropylacrylamide-grafted magnetic nanoparticles were prepared using silica-coated magnetic nanoparticles as a substrate for radical copolymerization of allyl glycidyl ether and N-isopropylacrylamide. Chitosan was coupled with the prepared nanoparticles by opening the epoxy ring of the allyl glycidyl ether. The thermosensitive magnetic nanocarrier (TSMNC) obtained can be applied as a potent drug carrier. The TSMNC structure was characterized using Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, vibrating sample magnetometer, and elemental analysis. Its morphology and size were investigated using field emission scanning electron microscopy, transmission electron microscopy and dynamic light scattering. The feasibility of employing the TSMNC for adsorption and in vitro controlled release of the chemotherapeutic agent sorafenib was tested. The effect of the adsorption parameters of pH, temperature, and loading time of sorafenib onto TSMNC was evaluated. The adsorption data was fitted to the Langmuir and Freundlich isotherms and the relevant parameters derived. The drug release profile indicated that 88% of the adsorbed drug was released within 35 h at 45 °C and drug release was Fickian diffusion-controlled. The results confirmed that the TSMNC has a high adsorption capacity at low temperature and good controlled release in a slow rate at a high temperature and could be developed for further application as a drug nanocarrier. - Graphical abstract: Magnetic nanoparticles were functionalized with chitosan and N-isopropylacrylamide. It was evaluated for sorafenib (SFB) adsorption and tested as a controlled-release system in response to changes in temperature. The TSMNC showed superparamagnetic properties with a high adsorption capacity and desirable controlled release at below and above LCST. Display Omitted - Highlights: • A TSMNC was synthesized for controlled

  7. Glass transition and aging in dense suspensions of thermosensitive microgel particles

    NARCIS (Netherlands)

    Purnomo, E.H; van den Ende, Henricus T.M.; Vanapalli Veera, V.S.A.R.; Vanapalli, Srinivas; Mugele, Friedrich Gunther

    2008-01-01

    We report a thermosensitive microgel suspension that can be tuned reversibly between the glass state at low temperature and the liquid state at high temperature. Unlike hard spheres, we find that the glass transition for these suspensions is governed by both the volume fraction and the softness of

  8. Membrane distillation with porous metal hollow fibers for the concentration of thermo-sensitive solutions

    NARCIS (Netherlands)

    Shukla, Sushumna

    2014-01-01

    This thesis presents an original approach for the concentration of thermo-sensitive solutions: the Sweep Gas Membrane Distillation (SGMD) process. A new membrane contactor with metallic hollow fibers has been designed and allows the distillation process to be operational at low temperature. Heat is

  9. Ionic Conductivity of Polyelectrolyte Hydrogels.

    Science.gov (United States)

    Lee, Chen-Jung; Wu, Haiyan; Hu, Yang; Young, Megan; Wang, Huifeng; Lynch, Dylan; Xu, Fujian; Cong, Hongbo; Cheng, Gang

    2018-02-14

    Polyelectrolytes have many important functions in both living organisms and man-made applications. One key property of polyelectrolytes is the ionic conductivity due to their porous networks that allow the transport of water and small molecular solutes. Among polyelectrolytes, zwitterionic polymers have attracted huge attention for applications that involve ion transport in a polyelectrolyte matrix; however, it is still unclear how the functional groups of zwitterionic polymer side chains affect their ion transport and swelling properties. In this study, zwitterionic poly(carboxybetaine acrylamide), poly(2-methacryloyloxyethyl phosphorylcholine), and poly(sulfobetaine methacrylate) hydrogels were synthesized and their ionic conductivity was studied and compared to cationic, anionic, and nonionic hydrogels. The change of the ionic conductivity of zwitterionic and nonionic hydrogels in different saline solutions was investigated in detail. Zwitterionic hydrogels showed much higher ionic conductivity than that of the widely used nonionic poly(ethylene glycol) methyl ether methacrylate hydrogel in all tested solutions. For both cationic and anionic hydrogels, the presence of mobile counterions led to high ionic conductivity in low salt solutions; however, the ionic conductivity of zwitterionic hydrogels surpassed that of cationic and ionic hydrogels in high salt solutions. Cationic and anionic hydrogels showed much higher water content than that of zwitterionic hydrogels in deionized water; however, the cationic hydrogels shrank significantly with increasing saline concentration. This work provides insight into the effects of polyelectrolyte side chains on ion transport. This can guide us in choosing better polyelectrolytes for a broad spectrum of applications, including bioelectronics, neural implants, battery, and so on.

  10. Injectable Thermoresponsive Hydrogel Formed by Alginate-g-Poly(N-isopropylacrylamide) That Releases Doxorubicin-Encapsulated Micelles as a Smart Drug Delivery System.

    Science.gov (United States)

    Liu, Min; Song, Xia; Wen, Yuting; Zhu, Jing-Ling; Li, Jun

    2017-10-18

    In this work, we have synthesized a thermoresponsive copolymer, alginate-g-poly(N-isopropylacrylamide) (alginate-g-PNIPAAm) by conjugating PNIPAAm to alginate, where PNIPAAm with different molecular weights and narrow molecular weight distribution was synthesized by atomic transfer radical polymerization. The copolymer dissolved in water or phosphate-buffered saline buffer solution at room temperature and formed self-assembled micelles with low critical micellization concentrations when the temperature increased to above their critical micellization temperatures. At higher concentration, that is, 7.4 wt % in water, the copolymer formed solutions at 25 °C and turned into thermosensitive hydrogels when temperature increased to the body temperature (37 °C). Herein, we hypothesized that the thermoresponsive hydrogels could produce self-assembled micelles with the dissolution of the alginate-g-PNIPAAm hydrogels in a biological fluid or drug release medium. If the drug was hydrophobic, the hydrogel eventually could release and produce drug-encapsulated micelles. In our experiments, we loaded the anticancer drug doxorubicin (DOX) into the alginate-g-PNIPAAm hydrogels and demonstrated that the hydrogels released DOX-encapsulated micelles in a sustained manner. The slowly released DOX-loaded micelles enhanced the cellular uptake of DOX in multidrug resistant AT3B-1 cells, showing the effect of overcoming the drug resistance and achieving better efficiency for killing the cancer cells. Therefore, the injectable thermoresponsive hydrogels formed by alginate-g-PNIPAAm and loaded with DOX turned into a smart drug delivery system, releasing DOX-encapsulated micelles in a sustained manner, showing great potential for overcoming the drug resistance in cancer therapy.

  11. Physico - chemical characterization of gamma irradiated PVP-honey-glycerine hydrogel

    International Nuclear Information System (INIS)

    Darmawan Darwis; Lely Hardiningsih; Farah Nurlidar

    2010-01-01

    Research to investigate physico-chemical characterizatics of hydrogel wound dressing containing 6% (b/v) of honey and various concentrations of glycerine from 0-5% (b/v) has been done. Nine series of hydrogel formulas with various composition of PVP hydrogel were irradiated using gamma rays at a dose of 25 kGy. The results showed that addition of honey 6% and glycerine up to 5% lead to the formation of hydrogel with following properties: sterile, transparence, browning color, improved flexibility, conformability to skin and resistance against mould. The PVP-honey-glycerine hydrogel also showed lower water favor evaporation at 37 o C and higher water absorption properties compared to basic formula (without additional of honey and glycerine). (author)

  12. Smart nanocomposite hydrogels based on azo crosslinked graphene oxide for oral colon-specific drug delivery

    Science.gov (United States)

    Hou, Lin; Shi, Yuyang; Jiang, Guixiang; Liu, Wei; Han, Huili; Feng, Qianhua; Ren, Junxiao; Yuan, Yujie; Wang, Yongchao; Shi, Jinjin; Zhang, Zhenzhong

    2016-08-01

    A safe and efficient nanocomposite hydrogel for colon cancer drug delivery was synthesized using pH-sensitive and biocompatible graphene oxide (GO) containing azoaromatic crosslinks as well as poly (vinyl alcohol) (PVA) (GO-N=N-GO/PVA composite hydrogels). Curcumin (CUR), an anti-cancer drug, was encapsulated successfully into the hydrogel through a freezing and thawing process. Fourier transform infrared spectroscopy, scanning electron microscopy and Raman spectroscopy were performed to confirm the formation and morphological properties of the nanocomposite hydrogel. The hydrogels exhibited good swelling properties in a pH-sensitive manner. Drug release studies under conditions mimicking stomach to colon transit have shown that the drug was protected from being released completely into the physiological environment of the stomach and small intestine. In vivo imaging analysis, pharmacokinetics and a distribution of the gastrointestinal tract experiment were systematically studied and evaluated as colon-specific drug delivery systems. All the results demonstrated that GO-N=N-GO/PVA composite hydrogels could protect CUR well while passing through the stomach and small intestine to the proximal colon, and enhance the colon-targeting ability and residence time in the colon site. Therefore, CUR loaded GO-N=N-GO/PVA composite hydrogels might potentially provide a theoretical basis for the treatment of colon cancer with high efficiency and low toxicity.

  13. Temperature responsive hydrogel magnetic nanocomposites for hyperthermia and metal extraction applications

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, N. Narayana, E-mail: nagireddynarayana@gmail.com [Center for Advanced Biomaterials for Healthcare, Istituto Italiano di Tecnologia@CRIB, Largo Barsanti e Matteucci 53, 80125 Napoli (Italy); Ravindra, S. [Department of Physics, College of Science, Engineering and Technology, University of South Africa, Johannesburg 1709 (South Africa); Reddy, N. Madhava [Department of Environmental Science, Gates Institute of Technology, NH-7, Gooty, Anantapuram, Andhra Pradesh (India); Rajinikanth, V. [Department of Physics, College of Science, Engineering and Technology, University of South Africa, Johannesburg 1709 (South Africa); Raju, K. Mohana [Synthetic Polymer Laboratory, Department of Polymer Science & Technology, S.K. University, Anantapuram, Andhra Pradesh (India); Vallabhapurapu, Vijaya Srinivasu [Department of Physics, College of Science, Engineering and Technology, University of South Africa, Johannesburg 1709 (South Africa)

    2015-11-15

    The present work deals with the development of temperature and magnetic responsive hydrogel networks based on poly (N-isopropylacrylamide)/acrylamido propane sulfonic acid. The hydrogel matrices are synthesized by polymerizing N-isopropylacrylamide (NIPAM) monomer in the presence of acrylamido propane sulphonicacid (AMPS) using a cross-linker (N,N-methylenebisacrylamide, MBA) and redox initiating system [ammonium persulphate (APS)/tetramethylethylenediamine (TMEDA)]. The magnetic nanoparticles are generated throughout the hydrogel networks using in situ method by incorporating iron ions and subsequent treatment with ammonia. A series of hydrogel-magnetic nanocomposites (HGMNC) are developed by varying AMPS composition. The synthesized hydrogel magnetic nanocomposites (HGMNC) are characterized by using Fourier Transform Infrared (FTIR) Spectroscopy, X-ray diffraction (XRD), Thermal Analyses and Electron Microscopy analysis (Scanning and Transmission Electron Microscope). The metal extraction capacities of the prepared hydrogel (HG) and hydrogel magnetic nanocomposites (HGMNC) were studied at different temperatures. The results suggest that HGMNCs have higher extraction capacity compared to HG and HG loaded iron ions. This data also reveals that the extraction of metals by hydrogel magnetic nanocomposites (HGMNCs) is higher at higher temperatures than room temperature. The prepared HGMNCs are also subjected to hyperthermia (cancer therapy) studies. - Highlights: • We have developed temperature responsive hydrogel magnetic nanocomposites. • Addition of AMPS monomer to this magnetic hydrogel enhances the temperature sensitivity to 40–43 °C. • Similarly the sulfonic groups present in the AMPS units enhances the swelling ratio of magnetic hydrogels. • AMPS acts as good stabilizing agent for nanoparticles in the magnetic nanogel.

  14. Temperature responsive hydrogel magnetic nanocomposites for hyperthermia and metal extraction applications

    International Nuclear Information System (INIS)

    Reddy, N. Narayana; Ravindra, S.; Reddy, N. Madhava; Rajinikanth, V.; Raju, K. Mohana; Vallabhapurapu, Vijaya Srinivasu

    2015-01-01

    The present work deals with the development of temperature and magnetic responsive hydrogel networks based on poly (N-isopropylacrylamide)/acrylamido propane sulfonic acid. The hydrogel matrices are synthesized by polymerizing N-isopropylacrylamide (NIPAM) monomer in the presence of acrylamido propane sulphonicacid (AMPS) using a cross-linker (N,N-methylenebisacrylamide, MBA) and redox initiating system [ammonium persulphate (APS)/tetramethylethylenediamine (TMEDA)]. The magnetic nanoparticles are generated throughout the hydrogel networks using in situ method by incorporating iron ions and subsequent treatment with ammonia. A series of hydrogel-magnetic nanocomposites (HGMNC) are developed by varying AMPS composition. The synthesized hydrogel magnetic nanocomposites (HGMNC) are characterized by using Fourier Transform Infrared (FTIR) Spectroscopy, X-ray diffraction (XRD), Thermal Analyses and Electron Microscopy analysis (Scanning and Transmission Electron Microscope). The metal extraction capacities of the prepared hydrogel (HG) and hydrogel magnetic nanocomposites (HGMNC) were studied at different temperatures. The results suggest that HGMNCs have higher extraction capacity compared to HG and HG loaded iron ions. This data also reveals that the extraction of metals by hydrogel magnetic nanocomposites (HGMNCs) is higher at higher temperatures than room temperature. The prepared HGMNCs are also subjected to hyperthermia (cancer therapy) studies. - Highlights: • We have developed temperature responsive hydrogel magnetic nanocomposites. • Addition of AMPS monomer to this magnetic hydrogel enhances the temperature sensitivity to 40–43 °C. • Similarly the sulfonic groups present in the AMPS units enhances the swelling ratio of magnetic hydrogels. • AMPS acts as good stabilizing agent for nanoparticles in the magnetic nanogel

  15. Methylcellulose Based Thermally Reversible Hydrogel System for Tissue Engineering Applications

    Directory of Open Access Journals (Sweden)

    Ram V. Devireddy

    2013-06-01

    Full Text Available The thermoresponsive behavior of a Methylcellulose (MC polymer was systematically investigated to determine its usability in constructing MC based hydrogel systems in cell sheet engineering applications. Solution-gel analyses were made to study the effects of polymer concentration, molecular weight and dissolved salts on the gelation of three commercially available MCs using differential scanning calorimeter and rheology. For investigation of the hydrogel stability and fluid uptake capacity, swelling and degradation experiments were performed with the hydrogel system exposed to cell culture solutions at incubation temperature for several days. From these experiments, the optimal composition of MC-water-salt that was able to produce stable hydrogels at or above 32 °C, was found to be 12% to 16% of MC (Mol. wt. of 15,000 in water with 0.5× PBS (~150mOsm. This stable hydrogel system was then evaluated for a week for its efficacy to support the adhesion and growth of specific cells in culture; in our case the stromal/stem cells derived from human adipose tissue derived stem cells (ASCs. The results indicated that the addition (evenly spread of ~200 µL of 2 mg/mL bovine collagen type -I (pH adjusted to 7.5 over the MC hydrogel surface at 37 °C is required to improve the ASC adhesion and proliferation. Upon confluence, a continuous monolayer ASC sheet was formed on the surface of the hydrogel system and an intact cell sheet with preserved cell–cell and cell–extracellular matrix was spontaneously and gradually detached when the grown cell sheet was removed from the incubator and exposed to room temperature (~30 °C within minutes.

  16. Methylcellulose based thermally reversible hydrogel system for tissue engineering applications.

    Science.gov (United States)

    Thirumala, Sreedhar; Gimble, Jeffrey M; Devireddy, Ram V

    2013-06-25

    The thermoresponsive behavior of a Methylcellulose (MC) polymer was systematically investigated to determine its usability in constructing MC based hydrogel systems in cell sheet engineering applications. Solution-gel analyses were made to study the effects of polymer concentration, molecular weight and dissolved salts on the gelation of three commercially available MCs using differential scanning calorimeter and rheology. For investigation of the hydrogel stability and fluid uptake capacity, swelling and degradation experiments were performed with the hydrogel system exposed to cell culture solutions at incubation temperature for several days. From these experiments, the optimal composition of MC-water-salt that was able to produce stable hydrogels at or above 32 °C, was found to be 12% to 16% of MC (Mol. wt. of 15,000) in water with 0.5× PBS (~150mOsm). This stable hydrogel system was then evaluated for a week for its efficacy to support the adhesion and growth of specific cells in culture; in our case the stromal/stem cells derived from human adipose tissue derived stem cells (ASCs). The results indicated that the addition (evenly spread) of ~200 µL of 2 mg/mL bovine collagen type -I (pH adjusted to 7.5) over the MC hydrogel surface at 37 °C is required to improve the ASC adhesion and proliferation. Upon confluence, a continuous monolayer ASC sheet was formed on the surface of the hydrogel system and an intact cell sheet with preserved cell-cell and cell-extracellular matrix was spontaneously and gradually detached when the grown cell sheet was removed from the incubator and exposed to room temperature (~30 °C) within minutes.

  17. Physical-chemical characterization of different hydrogels Formulations

    International Nuclear Information System (INIS)

    Rodriguez, Y.; Romero, M.; Soler, I.; Saldivar, D.

    2001-01-01

    They were carried out swelling studies at 37 0C of different hydrogels formulations whose composition was the following one: 3% PEG-1000, 1% Agar and concentrations of PVP and NVP 7, 10 and 14% and a maximum thickness of 2 mm, this formulations were irradiated to 25 kGy in a self-shield irradiator of 60Co and the same time studies of the mechanical properties. It was obtained that the hydrogels of PVP absorbs more water than those of NVP. It was described pseudo-Fickian s kinetic whose exponent diffusional is in the following range: 0.5 0.6

  18. Evaluation of fibrin-gelatin hydrogel as biopaper for application in skin bioprinting: An in-vitro study.

    Science.gov (United States)

    Hakam, Mohammad Sadjad; Imani, Rana; Abolfathi, Nabiollah; Fakhrzadeh, Hossein; Sharifi, Ali Mohammad

    2016-01-01

    Recent advances in tissue engineering have led to the development of the concept of bioprinting as an interesting alternative to traditional tissue engineering approaches. Biopaper, a biomimetic hydrogel, is an essential component of the bioprinting process. The aim of this work was to synthesize a biopaper made of fibrin-gelatin hybrid hydrogel for application in skin bioprinting. Different composition percentages of the two biopolymer hydrogels, fibrin-gelatin, have been studied for the construction of the biopaper and were examined in terms of water absorption, biodegradability, glucose absorption, mechanical properties and water vapor transmission. Subsequently, tissue fusion study was performed on prepared 3T3 fibroblast cell line pellets embedded into the hydrogel. Based on the obtained results, fibrin-gelatin blend hydrogel with the same proportion of two components provides a natural scaffold for fibroblast-based bioink embedding and culture. The suggested optimized hydrogel was a suitable candidate as a biopaper for skin bioprinting technology.

  19. The Formation Mechanism of Hydrogels.

    Science.gov (United States)

    Lu, Liyan; Yuan, Shiliang; Wang, Jing; Shen, Yun; Deng, Shuwen; Xie, Luyang; Yang, Qixiang

    2017-06-12

    Hydrogels are degradable polymeric networks, in which cross-links play a vital role in structure formation and degradation. Cross-linking is a stabilization process in polymer chemistry that leads to the multi-dimensional extension of polymeric chains, resulting in network structures. By cross-linking, hydrogels are formed into stable structures that differ from their raw materials. Generally, hydrogels can be prepared from either synthetic or natural polymers. Based on the types of cross-link junctions, hydrogels can be categorized into two groups: the chemically cross-linked and the physically cross-linked. Chemically cross-linked gels have permanent junctions, in which covalent bonds are present between different polymer chains, thus leading to excellent mechanical strength. Although chemical cross-linking is a highly resourceful method for the formation of hydrogels, the cross-linkers used in hydrogel preparation should be extracted from the hydrogels before use, due to their reported toxicity, while, in physically cross-linked gels, dissolution is prevented by physical interactions, such as ionic interactions, hydrogen bonds or hydrophobic interactions. Physically cross-linked methods for the preparation of hydrogels are the alternate solution for cross-linker toxicity. Both methods will be discussed in this essay. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  20. Hydrogel nanoparticles in drug delivery.

    Science.gov (United States)

    Hamidi, Mehrdad; Azadi, Amir; Rafiei, Pedram

    2008-12-14

    Hydrogel nanoparticles have gained considerable attention in recent years as one of the most promising nanoparticulate drug delivery systems owing to their unique potentials via combining the characteristics of a hydrogel system (e.g., hydrophilicity and extremely high water content) with a nanoparticle (e.g., very small size). Several polymeric hydrogel nanoparticulate systems have been prepared and characterized in recent years, based on both natural and synthetic polymers, each with its own advantages and drawbacks. Among the natural polymers, chitosan and alginate have been studied extensively for preparation of hydrogel nanoparticles and from synthetic group, hydrogel nanoparticles based on poly (vinyl alcohol), poly (ethylene oxide), poly (ethyleneimine), poly (vinyl pyrrolidone), and poly-N-isopropylacrylamide have been reported with different characteristics and features with respect to drug delivery. Regardless of the type of polymer used, the release mechanism of the loaded agent from hydrogel nanoparticles is complex, while resulting from three main vectors, i.e., drug diffusion, hydrogel matrix swelling, and chemical reactivity of the drug/matrix. Several crosslinking methods have been used in the way to form the hydrogel matix structures, which can be classified in two major groups of chemically- and physically-induced crosslinking.

  1. Poly(ethylene glycol)-based thiol-ene hydrogel coatings: curing chemistry, aqueous stability, and potential marine antifouling applications

    NARCIS (Netherlands)

    Lundberg, P.; Bruin, A.; Klijnstra, J.W.; Nyström, A.M.; Johansson, M.; Malkoch, M.; Hult, A.

    2010-01-01

    Photocured thiol-ene hydrogel coatings based on poly(ethylene glycol) (PEG) were investigated for marine antifouling purposes. By varying the PEG length, vinylic end-group, and thiol cross-linker, a library of hydrogel coatings with different structural composition was efficiently accomplished, with

  2. Structuring and calorie control of bakery products by templating batter with ultra melt-resistant food-grade hydrogel beads.

    Science.gov (United States)

    Thompson, Benjamin R; Horozov, Tommy S; Stoyanov, Simeon D; Paunov, Vesselin N

    2017-08-01

    We report the use of a temperature insensitive, food-grade hydrogel to reduce the caloric density of pancakes that were prepared at temperatures much higher than the boiling point of water. This cheap, facile method utilises a mixed agar-methylcellulose hydrogel, which was blended to produce a slurry of hydrogel microbeads. The pancake batter was mixed with a controlled volume percentage of slurry of hydrogel beads and cooked. From bomb calorimetry experiments, the composites were found to have a reduced caloric density that reflects the volume percentage of hydrogel beads mixed with the batter. Using this procedure, we were able to reduce the caloric density of pancakes by up to 23 ± 3% when the volume percentage of hydrogel beads initially used was 25%. The method is not limited to pancakes and could potentially be applied to various other food products. The structure and morphology of the freeze-dried pancakes and pancake-hydrogel composites were investigated and pores of a similar size to the hydrogel beads were found, confirming that the gel beads maintained their structure during the cooking process. There is scope for further development of this method by the encapsulation of nutritionally beneficial or flavour enhancing ingredients within the hydrogel beads.

  3. Structure of chitosan thermosensitive gels containing graphene oxide

    Science.gov (United States)

    Tylman, Michał; Pieklarz, Katarzyna; Owczarz, Piotr; Maniukiewicz, Waldemar; Modrzejewska, Zofia

    2018-06-01

    The supramolecular hydrogels of chitosan and graphene oxide (GO) have been prepared at temperature of the human body, by controlling the concentration of GO and ratio of chitosan to GO. During the preparation of gels the sodium β-glycerophosphate (Na-β-GP) was used as a neutralizing agent. The structure of obtained gels was determined on the basis of FTIR spectra and XRD diffraction patterns. The results of structural studies have been referenced to gels without graphene oxide. It was found that the gels crystalline structure after the addition of GO does not change. The XRD diffraction patterns are characterized by a number of peaks associated with precipitated NaCl during drying and presence of sodium β-glycerophosphate.

  4. Antimicrobial activity and the mechanism of silver nanoparticle thermosensitive gel

    Directory of Open Access Journals (Sweden)

    Chen M

    2011-11-01

    Full Text Available Meiwan Chen1,2,‡, Zhiwen Yang1,‡, Hongmei Wu1, Xin Pan1, Xiaobao Xie3, Chuanbin Wu11Research and Development Center of Pharmaceutical Engineering, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China; 2State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau, China; 3Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangzhou, China ‡These authors contributed equally to this workPurpose: The purpose of the present study was to elucidate the antimicrobial activity and mechanism of silver nanoparticles incorporated into thermosensitive gel (S-T-Gel on Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa.Patients and methods: This study investigated the growth, permeability, and morphology of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa cells in order to observe the action of S-T-Gel on the membrane structure of these three bacteria. The cell morphology of normal and treated bacteria cells was assessed by transmission electron microscopy (TEM, and the effects of S-T-Gel on genome DNA of bacterial cells were evaluated by agarose gel electrophoresis.Results: S-T-Gel showed promising activity against Staphylococcus aureus and moderate activity against Escherichia coli and Pseudomonas aeruginosa. The observation with TEM suggested that S-T-Gel may destroy the structure of bacterial cell membranes in order to enter the bacterial cell. S-T-Gel then condensed DNA and combined and coagulated with the cytoplasm of the damaged bacteria, resulting in the leakage of the cytoplasmic component and the eventual death of these three bacteria. In addition, the analysis of agarose gel electrophoresis demonstrated that S-T-Gel could increase the decomposability of genome DNA.Conclusion: These results about promising antimicrobial activity and mechanism of S-T-Gel may be useful for further research

  5. Interfacial self-healing of nanocomposite hydrogels: Theory and experiment

    Science.gov (United States)

    Wang, Qiming; Gao, Zheming; Yu, Kunhao

    2017-12-01

    Polymers with dynamic bonds are able to self-heal their fractured interfaces and restore the mechanical strengths. It is largely elusive how to analytically model this self-healing behavior to construct the mechanistic relationship between the self-healing properties (e.g., healed interfacial strength and equilibrium healing time) and the material compositions and healing conditions. Here, we take a self-healable nanocomposite hydrogel as an example to illustrate an interfacial self-healing theory for hydrogels with dynamic bonds. In the theory, we consider the free polymer chains diffuse across the interface and reform crosslinks to bridge the interface. We analytically reveal that the healed strengths of nanocomposite hydrogels increase with the healing time in an error-function-like form. The equilibrium self-healing time of the full-strength recovery decreases with the temperature and increases with the nanoparticle concentration. We further analytically reveal that the healed interfacial strength decreases with increasing delaying time before the healing process. The theoretical results quantitatively match with our experiments on nanosilica hydrogels, and also agree well with other researchers' experiments on nanoclay hydrogels. We expect that this theory would open promising avenues for quantitative understanding of the self-healing mechanics of various polymers with dynamic bonds, and offer insights for designing high-performance self-healing polymers.

  6. Biocompatible nanomaterials based on dendrimers, hydrogels and hydrogel nanocomposites for use in biomedicine

    Science.gov (United States)

    Khoa Nguyen, Cuu; Quyen Tran, Ngoc; Phuong Nguyen, Thi; Hai Nguyen, Dai

    2017-03-01

    Over the past decades, biopolymer-based nanomaterials have been developed to overcome the limitations of other macro- and micro- synthetic materials as well as the ever increasing demand for the new materials in nanotechnology, biotechnology, biomedicine and others. Owning to their high stability, biodegradability, low toxicity, and biocompatibility, biopolymer-based nanomaterials hold great promise for various biomedical applications. The pursuit of this review is to briefly describe our recent studies regarding biocompatible biopolymer-based nanomaterials, particularly in the form of dendrimers, hydrogels, and hydrogel composites along with the synthetic and modification approaches for the utilization in drug delivery, tissue engineering, and biomedical implants. Moreover, in vitro and in vivo studies for the toxicity evaluation are also discussed.

  7. Fabrication of Multiple-Layered Hydrogel Scaffolds with Elaborate Structure and Good Mechanical Properties via 3D Printing and Ionic Reinforcement.

    Science.gov (United States)

    Wang, Xiaotong; Wei, Changzheng; Cao, Bin; Jiang, Lixia; Hou, Yongtai; Chang, Jiang

    2018-05-30

    A major challenge in three-dimensional (3D) printing of hydrogels is the fabrication of stable constructs with high precision and good mechanical properties and biocompatibility. Existing methods typically feature complicated reinforcement steps or use potentially toxic components, such as photocuring polymers and crosslinking reagents. In this study, we used a thermally sensitive hydrogel, hydroxybutyl chitosan (HBC), for 3D-printing applications. For the first time, we demonstrated that this modified polysaccharide is affected by the specific ion effect. As the salt concentration was increased and stronger kosmotropic anions were used, the lower critical solution temperature of the HBC decreased and the storage modulus was improved, indicating a more hydrophobic structure and stronger molecular chain interactions. On the basis of the thermosensitivity and the ion effects of HBC, a 25-layered hydrogel scaffold with strong mechanical properties and an elaborate structure was prepared via a 3D-printing method and one-step ionic post-treatment. In particular, the scaffold treated with 10% NaCl solution exhibited a tunable elastic modulus of 73.2 kPa to 40 MPa and excellent elastic recovery, as well as biodegradability and cytocompatibility, suggesting the potential for its applications to cartilage tissue repair. By simply controlling the temperature and salt concentrations, this novel approach provides a convenient and green route to improving the structural accuracy and regulating the properties of 3D-printed hydrogel constructs.

  8. HYDROGELS AND THEIR APLICATION AREAS

    Directory of Open Access Journals (Sweden)

    AÇIKEL Safiye Meriç

    2016-05-01

    Full Text Available Hydrogels, being polymeric material,are named “Hydrophilic Polymer” because of their capable of holding large amounts of water in their three-dimensional networks. Hydrogels is not solved in water; however they have been swollen to their balace volume. Because of this swell behavior, they can adsorb big quantity of water in this structure. So they can term of “three sized polymers” due to protect their existing shape. Their cross linked bound structures are able to covalent or ionic and also one polymer which can for use of hydrogel polymer, must have hydrophilic groups such as carboxyl, carbonyl, amine and amide in main chains or side chains, and because of these groups water bound the polymer and polymer start to swell with rising volume and mass. Swell behavior of hydrogel is interested in quantity of hydrophilic groups. Hydrogels can use in different industrial and environmental areas with this high amount water holding capacity. They are used in food industry, biomedical, bioengineering, biotechnology, veterinary, pharmacist, agriculture, telecommunication, etc. Especially in current life, baby nappy has been including inside hydrogel beads. Also they used in contact lens, artificial cornea, synthetic cartilage and gullet, controlled medicine release, surgery yarns. This article general inform about usage area of hydrogels.

  9. In-Vitro Release of Ketoprofen Behavior Loaded in Polyvinyl Alcohol / Acrylamide Hydrogels Prepared by Gamma Irradiation

    International Nuclear Information System (INIS)

    Mahmoud, Gh.A.; Hegazy, D.E.; Kamal, H.

    2014-01-01

    Hydrogels based on various ratios of polyvinyl alcohol (PVA) and acrylamide (AAm) were prepared by gamma radiation. The formed hydrogels were characterized by spectroscopic analysis (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and swelling studied. It was found that the thermal stability of the hydrogel decreases as the AAm content increases in the hydrogel. The higher the AAm content in the hydrogel, the lower the values of Tm and ΔH m . Ketoprofen was adopted as a model drug to study the adsorption and release behavior of (PVA/AAm) hydrogel. The drug adsorption was decreased by increasing AAm ratio in the hydrogel. From the in vitro drug release study in ph progressive media, the basic medium was showed comparatively the highest release and the (PVA/AAm) hydrogel of composition (70/30) was found to be the highest release one. The mechanism of Ketoprofen release from the (PVA/AAm) matrix was found to be non-Fickian mechanism for all investigated hydrogels at ph 7.

  10. Platelet-rich plasma loaded in situ-formed hydrogel enhances hyaline cartilage regeneration by CB1 upregulation.

    Science.gov (United States)

    Lee, Hye-Rim; Park, Kyung Min; Joung, Yoon Ki; Park, Ki Dong; Do, Sun Hee

    2012-11-01

    The efficacy of three-dimensional (3D) culture on the proliferation and maturation of chondrocytes seeded into a hydrogel scaffold was assessed. Three types of hydrogel were prepared for the 3D culture of primary isolated chondrocytes. Chondrocyte proliferation was assessed using a live/dead viability/cytotoxicity assay and semiquantitative RT-PCR after 3D culture in hydrogel. Cylindrical defects in the center of rat xyphoids were used for the implantation of platelet-rich plasma (PRP)/hydrogel composites. Rats were killed at day 7 postoperatively and evaluated histochemically and immunohistologically. Xyphoid chondrocytes proliferated well with time in hydrogels. In the PRP-containing hydrogels, xyphoid defects displayed early formation of chondroid matrix with massive peripheral infiltration of spindle cells. These results were consistent with Safranin-O staining for proteoglycans and immunohistochemistry for type II collagen. Gene expression analyses in vitro revealed aggrecan, type II collagen, and ChM-1 and CB1 upregulation by PRP/hydrogel. PRP/hydrogel provided a suitable environment for hyaline cartilaginous regeneration, leading to anti-inflammation by significant increase of CB1 and inhibiting vascular ingrowth via considerable upregulation of ChM-1. The results provide a valuable reference for the clinical application of hydrogel scaffolds for hyaline cartilage regeneration, as well as the use of autologous PRP to improve cellular proliferation and maturation of xyphoid repair. Copyright © 2012 Wiley Periodicals, Inc.

  11. Gamma ray-induced synthesis of hyaluronic acid/chondroitin sulfate-based hydrogels for biomedical applications

    Science.gov (United States)

    Zhao, Linlin; Gwon, Hui-Jeong; Lim, Youn-Mook; Nho, Young-Chang; Kim, So Yeon

    2015-01-01

    Hyaluronic acid (HA)/chondroitin sulfate (CS)/poly(acrylic acid) (PAAc) hydrogel systems were synthesized by gamma-ray irradiation without the use of additional initiators or crosslinking agents to achieve a biocompatible hydrogel system for skin tissue engineering. HA and CS derivatives with polymerizable residues were synthesized. Then, the hydrogels composed of glycosaminoglycans, HA, CS, and a synthetic ionic polymer, PAAc, were prepared using gamma-ray irradiation through simultaneous free radical copolymerization and crosslinking. The physicochemical properties of the HA/CS/PAAc hydrogels having various compositions were investigated to evaluate their feasibility as artificial skin substitutes. The gel fractions of the HA/CS/PAAc hydrogels increased in absorbed doses up to 15 kGy, and they exhibited 91-93% gel fractions under 15 kGy radiation. All of the HA/CS/PAAc hydrogels exhibited relatively high water contents of over 90% and reached an equilibrium swelling state within 24 h. The enzymatic degradation kinetics of the HA/CS/PAAc hydrogels depended on both the concentration of the hyaluronidase solution and the ratio of HA/CS/PAAc. The in vitro drug release profiles of the HA/CS/PAAc hydrogels were significantly influenced by the interaction between the ionic groups in the hydrogels and the ionic drug molecules as well as the swelling of the hydrogels. From the cytotoxicity results of human keratinocyte (HaCaT) cells cultured with extracts of the HA/CS/PAAc hydrogels, all of the HA/CS/PAAc hydrogel samples tested showed relatively high cell viabilities of more than 82%, and did not induce any significant adverse effects on cell viability.

  12. Effect of Transplanting Various Concentrations of a Composite of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells and Hyaluronic Acid Hydrogel on Articular Cartilage Repair in a Rabbit Model.

    Directory of Open Access Journals (Sweden)

    Yong-Beom Park

    Full Text Available Mesenchymal stem cells (MSCs are known to have therapeutic potential for cartilage repair. However, the optimal concentration of MSCs for cartilage repair remains unclear. Therefore, we aimed to explore the feasibility of cartilage repair by human umbilical cord blood-derived MSCs (hUCB-MSCs and to determine the optimal concentrations of the MSCs in a rabbit model.Osteochondral defects were created in the trochlear groove of femur in 55 rabbits. Four experimental groups (11 rabbits/group were treated by transplanting the composite of hUCB-MSCs and HA with various MSCs concentrations (0.1, 0.5, 1.0, and 1.5 x 107 cells/ml. One control group was left untreated. At 4, 8, and 16 weeks post-transplantation, the degree of cartilage repair was evaluated grossly and histologically.Overall, transplanting hUCB-MSCs and HA hydrogel resulted in cartilage repair tissue with better quality than the control without transplantation (P = 0.015 in 0.1, P = 0.004 in 0.5, P = 0.004 in 1.0, P = 0.132 in 1.5 x 107 cells/ml. Interestingly, high cell concentration of hUCB-MSCs (1.5×107 cells/ml was inferior to low cell concentrations (0.1, 0.5, and 1.0 x 107 cells/ml in cartilage repair (P = 0.394,P = 0.041, P = 0.699, respectively. The 0.5 x 107 cells/ml group showed the highest cartilage repair score at 4, 8 and 16 weeks post transplantation, and followed by 0.1x107 cells/ml group or 1.0 x 107 cell/ml group.The results of this study suggest that transplantation of the composite of hUCB-MSCs and HA is beneficial for cartilage repair. In addition, this study shows that optimal MSC concentration needs to be determined for better cartilage repair.

  13. Poroelastic Mechanical Effects of Hemicelluloses on Cellulosic Hydrogels under Compression

    Science.gov (United States)

    Lopez-Sanchez, Patricia; Cersosimo, Julie; Wang, Dongjie; Flanagan, Bernadine; Stokes, Jason R.; Gidley, Michael J.

    2015-01-01

    Hemicelluloses exhibit a range of interactions with cellulose, the mechanical consequences of which in plant cell walls are incompletely understood. We report the mechanical properties of cell wall analogues based on cellulose hydrogels to elucidate the contribution of xyloglucan or arabinoxylan as examples of two hemicelluloses displaying different interactions with cellulose. We subjected the hydrogels to mechanical pressures to emulate the compressive stresses experienced by cell walls in planta. Our results revealed that the presence of either hemicellulose increased the resistance to compression at fast strain rates. However, at slow strain rates, only xyloglucan increased composite strength. This behaviour could be explained considering the microstructure and the flow of water through the composites confirming their poroelastic nature. In contrast, small deformation oscillatory rheology showed that only xyloglucan decreased the elastic moduli. These results provide evidence for contrasting roles of different hemicelluloses in plant cell wall mechanics and man-made cellulose-based composite materials. PMID:25794048

  14. Extraction of americium (III) by thermosensitive polymer gel copolymerized with acidic phosphorus compound

    International Nuclear Information System (INIS)

    Takeshita, Kenji; Nakano, Yoshio; Matsumura, Tatsuro

    2001-01-01

    A new gel-liquid extraction using a thermosensitive gel was proposed. The thermosensitive gel shows the conformational change of polymer network with temperature, which is known as the phase transition phenomena of gel. The extraction rate and equilibrium of Am(III) in an aqueous solution containing nitrate ion were measured batchwise by using a thermosensitive gel, N-isopropylacrylamide (NIPA) copolymerized with 2-methacryloyloxy- ethylacidphosphate (MR). The effects of the conformational change of polymer network on the extraction rate and equilibrium were discussed. The distribution ratio of Am(III) showed a large value at higher than LCST (low critical solution temperature; 34degC) and was decreased by the phase transition of gel from shrinking to swelling with decreasing temperature. The extraction of Am(III) in the aqueous solution and the release of Am(III) extracted in the gel were repeated stably by the temperature swing operation between 40 and 3degC. The extraction mechanism of Am(III) was described simply as Am 3+ + 3R - OH=(R-O) 3 Am + 3H + (R-OH: MR). The equilibrium constant at the shrinking state (40degC) was more than 3 times of that at swelling state (3degC). The gel-phase diffusivity of Eu(III) used as a substitute of Am(III) was evaluated as the order of 10 -12 m 2 /s at either of 3 or 40degC, which was similar to those for practical extraction chromatographic resins. The temperature-response of gel for the extraction of Eu(III) was very excellent without delay even for the rapid temperature change at 10degC/min. These results suggest that the extraction and release of Am(III) in an aqueous solution can be controlled by the conformational change of polymer network of thermosensitive gel. (author)

  15. Oxide nanomembrane hybrids with enhanced mechano- and thermo-sensitivity for semitransparent epidermal electronics.

    Science.gov (United States)

    Park, Minjoon; Do, Kyungsik; Kim, Jaemin; Son, Donghee; Koo, Ja Hoon; Park, Jinkyung; Song, Jun-Kyul; Kim, Ji Hoon; Lee, Minbaek; Hyeon, Taeghwan; Kim, Dae-Hyeong

    2015-05-01

    Oxide nanomembrane hybrids with enhanced mechano- and thermo-sensitivity for semitransparent epidermal electronics are developed. The use of nanomaterials (single wall nanotubes and silver nanoparticles) embedded in the oxide nanomembranes significantly enhances mechanical and thermal sensitivities. These mechanical and thermal sensors are utilized in wheelchair control and hypothermia detection, which are useful for patients with strokes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Thermosensitive PLA based nanodispersion for targeting brain tumor via intranasal route

    International Nuclear Information System (INIS)

    Jain, Darshana S.; Bajaj, Amrita N.; Athawale, Rajani B.; Shikhande, Shruti S.; Pandey, Abhijeet; Goel, Peeyush N.; Gude, Rajiv P.; Patil, Satish; Raut, Preeti

    2016-01-01

    Delivery of drugs to the brain via nasal route has been studied by many researchers. However, low residence time, mucociliary clearance and enzymatically active environment of nasal cavity pose many challenges to successful nasal delivery of drugs. We aim to deliver methotrexate by designing thermosensitive nanodispersion exhibiting enhanced residence time in nasal cavity and bypassing the blood brain barrier (BBB). PLA nanoparticles were developed using solvent evaporation technique. The developed nanoparticles were further dispersed in prepared thermosensitive vehicle of poloxamer 188 and Carbopol 934 to impart the property of increased residence time. The formulated nanoparticles demonstrated no interaction with the simulated nasal fluids (SNF), mucin, serum proteins and erythrocytes which demonstrate the safety of developed formulation for nasal administration. The penetration property of nanoparticles though the nasal mucosa was higher than the pure drug due to low mucociliary clearance. The developed nanoparticles diffused though the membrane pores and rapidly distributed into the brain portions compared to the pure drug. There was detectable and quantifiable amount of drug seen in the brain as demonstrated by in vivo brain distribution studies with considerably low amount of drug deposition in the lungs. The pharmacokinetic parameters demonstrated the enhancement in circulation half life, area under curve (AUC) and Cmax of the drug when administered intranasal in encapsulated form. Thus, the thermosensitive nanodispersions are surely promising delivery systems for delivering anticancer agents though the nasal route for potential treatment of brain tumors. - Highlights: • The present investigation explores intra-nasal route as potential route for targeting brain tumor. • Thermosensitive nanodispersion has been formulated for enhancing nasal residence time. • PLA nanoparticles enhance penetration into the brain owing to hydrophobic nature and small size

  17. Zielgerichtete Chemotherapie solider Tumoren durch thermosensitive Liposomen in Kombination mit Doxorubicin, Gemcitabin und Mitomycin C

    OpenAIRE

    Limmer, Simone

    2014-01-01

    Auf DPPG2 basierende thermosensitive Liposomen (TSL) mit Hyperthermie (HT) induzierter zielgerichteter Wirkstofffreisetzung sind eine viel-versprechende Behandlungsstrategie in der Krebstherapie. TSL können als Wirkstoffträgersysteme die Zirkulationszeit und Anreicherung von Wirkstoffen im Zielgewebe erhöhen. Die vielfältigen Krebserkrankungen zeigen unterschiedliches Tumoransprechen auf die routinemäßig eingesetzten Zytostatika. Daher wäre es vorteilhaft, verschiedene Wirkstoffe in TSL e...

  18. Thermosensitive PLA based nanodispersion for targeting brain tumor via intranasal route

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Darshana S., E-mail: darshanaj_cup@yahoo.com [C.U. Shah College of Pharmacy, S.N.D.T Women' s University, Juhu Tara Road, Santacruz (West), Mumbai 400 049 (India); Bajaj, Amrita N. [C.U. Shah College of Pharmacy, S.N.D.T Women' s University, Juhu Tara Road, Santacruz (West), Mumbai 400 049 (India); Athawale, Rajani B., E-mail: rajani.athawale@gmail.com [C.U. Shah College of Pharmacy, S.N.D.T Women' s University, Juhu Tara Road, Santacruz (West), Mumbai 400 049 (India); Shikhande, Shruti S. [C.U. Shah College of Pharmacy, S.N.D.T Women' s University, Juhu Tara Road, Santacruz (West), Mumbai 400 049 (India); Pandey, Abhijeet [H. R Patel Institute of Pharmaceutical Education and Research, Shirpur, Maharashtra (India); Goel, Peeyush N.; Gude, Rajiv P. [Gude Lab, Advanced Centre for Treatment, Research & Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai 410 210 (India); Patil, Satish; Raut, Preeti [Cipla Pvt. Ltd., Vikhroli (West), Mumbai (India)

    2016-06-01

    Delivery of drugs to the brain via nasal route has been studied by many researchers. However, low residence time, mucociliary clearance and enzymatically active environment of nasal cavity pose many challenges to successful nasal delivery of drugs. We aim to deliver methotrexate by designing thermosensitive nanodispersion exhibiting enhanced residence time in nasal cavity and bypassing the blood brain barrier (BBB). PLA nanoparticles were developed using solvent evaporation technique. The developed nanoparticles were further dispersed in prepared thermosensitive vehicle of poloxamer 188 and Carbopol 934 to impart the property of increased residence time. The formulated nanoparticles demonstrated no interaction with the simulated nasal fluids (SNF), mucin, serum proteins and erythrocytes which demonstrate the safety of developed formulation for nasal administration. The penetration property of nanoparticles though the nasal mucosa was higher than the pure drug due to low mucociliary clearance. The developed nanoparticles diffused though the membrane pores and rapidly distributed into the brain portions compared to the pure drug. There was detectable and quantifiable amount of drug seen in the brain as demonstrated by in vivo brain distribution studies with considerably low amount of drug deposition in the lungs. The pharmacokinetic parameters demonstrated the enhancement in circulation half life, area under curve (AUC) and Cmax of the drug when administered intranasal in encapsulated form. Thus, the thermosensitive nanodispersions are surely promising delivery systems for delivering anticancer agents though the nasal route for potential treatment of brain tumors. - Highlights: • The present investigation explores intra-nasal route as potential route for targeting brain tumor. • Thermosensitive nanodispersion has been formulated for enhancing nasal residence time. • PLA nanoparticles enhance penetration into the brain owing to hydrophobic nature and small size

  19. Preparation and properties of polyvinyl alcohol (PVA) and hydroxylapatite (HA) hydrogels for cartilage tissue engineering.

    Science.gov (United States)

    Yuan, F; Ma, M; Lu, L; Pan, Z; Zhou, W; Cai, J; Luo, S; Zeng, W; Yin, F

    2017-05-20

    A novel bioactive hydrogel for cartilage tissue based on polyvinyl alcohol (PVA) and hydroxylapatite (HA) were prepared, the effects of its component contents on the mechanical properties and microstructure of the hydrogel were investigated. The important properties of the scaffold composites, such as density, porosity, compressive modulus and microstructure were studied and analyzed through various measurements and methods. The biodegradability of hydrogel was evaluated by soaking the samples into artificial degradation solution at body temperature (36 - 37 oC) in vitro. Experimental results showed that the PVA/HA hydrogels had a density of 0.572 - 0.683 g/cm3, a porosity of 63.25 - 96.14% and a compressive modulus of 5.62 - 8.24 MP. The HA compound in the hydrogels enhanced the biodegradation significantly and linearly increased the rate of biodegradation by 2.3 - 8.5 %. The compressive modulus of PVA/HA exhibited a linear reduce to 0.86 - 1.53 MP with the time of degradation. The scaffold composites PVA/HA possess a high porosity, decent compressive modulus and good biodegradability. After further optimizing the structure and properties, this composite might be considered as novel hydrogel biomaterials to be applied in the field of cartilage tissue engineering.

  20. Synthesis and Thermosensitive Behavior of Polyacrylamide Copolymers and Their Applications in Smart Textiles

    Directory of Open Access Journals (Sweden)

    Tao Chen

    2015-05-01

    Full Text Available We tuned the lower critical solution temperature (LCST of amphiphilic poly(N-isopropylacrylamide (PNIPAAm via copolymerization with a hydrophilic comonomer of N-hydroxymethyl acrylamide (NHMAAm. A series of copolymers P(NIPAAm-co-NHMAAm were synthesized by atom transfer radical polymerization (ATRP using CuBr/(N,N,N',N',N''-Pentamethyldiethylenetriamine (PMDETA as a catalyst system and 2-bromo ethyl isobutyrate (EBiB as an initiator. The copolymers were well characterized by Fourier transform infrared spectroscopy (FT-IR, 1H Nuclear magnetic resonance (NMR, and Thermogravimetric analysis (TGA. The copolymers followed a simple rule in their thermosensitive behaviors and have a linear increase in the LCST as a function of NHMAAm mol%. The thermosensitive properties of the copolymer films were investigated and demonstrated hydrophilic-hydrophobic transitions. Finally, the copolymer was grafted onto cotton fabrics using citric acid (CA as a crosslinking agent and sodium hypophosphite (SHP as a catalyst following a two dipping, two padding process. The large number of hydroxyl groups in the copolymer makes grafting convenient and firm. The grafted cotton fabrics show obvious thermosensitive behaviors. The results demonstrate that the cotton fabrics become more hydrophobic when the temperature is higher than the LCST. This study presents a valuable route towards temperature-responsive smart textiles and their potential applications.

  1. Molecular design of light-responsive hydrogels, for in situ generation of fast and reversible valves for microfluidic applications

    NARCIS (Netherlands)

    Schiphorst, ter J.; Coleman, S.; Stumpel, J.E.; Ben Azouz, A.; Diamond, D.; Schenning, A.P.H.J.

    2015-01-01

    Reversible light-responsive hydrogel valves with response characteristics compatible for microfluidics have been obtained by optimization of molecular design of spiropyran photoswitches and gel composition. Self-protonating gel formulations were exploited, wherein acrylic acid was copolymerized in

  2. Cytocompatible cellulose hydrogels containing trace lignin

    International Nuclear Information System (INIS)

    Nakasone, Kazuki; Kobayashi, Takaomi

    2016-01-01

    Sugarcane bagasse was used as a cellulose resource to prepare transparent and flexible cellulose hydrogel films. On the purification process from bagasse to cellulose, the effect of lignin residues in the cellulose was examined for the properties and cytocompatibility of the resultant hydrogel films. The cellulose was dissolved in lithium chloride/N,N-dimethylacetamide solution and converted to hydrogel films by phase inversion. In the purification process, sodium hydroxide (NaOH) treatment time was changed from 1 to 12 h. This resulted in cellulose hydrogel films having small amounts of lignin from 1.62 to 0.68%. The remaining lignin greatly affected hydrogel properties. Water content of the hydrogel films was increased from 1153 to 1525% with a decrease of lignin content. Moreover, lower lignin content caused weakening of tensile strength from 0.80 to 0.43 N/mm"2 and elongation from 45.2 to 26.5%. Also, similar tendency was observed in viscoelastic behavior of the cellulose hydrogel films. Evidence was shown that the lignin residue was effective for the high strength of the hydrogel films. In addition, scanning probe microscopy in the morphological observation was suggested that the trace lignin in the cellulose hydrogel affected the cellulose fiber aggregation in the hydrogel network. The trace of lignin in the hydrogels also influenced fibroblast cell culture on the hydrogel films. The hydrogel film containing 1.68% lignin showed better fibroblast compatibility as compared to cell culture polystyrene dish used as reference. - Highlights: • Cellulose hydrogel films with trace lignin were obtained from sugarcane bagasse. • Lignin content was found to be in the range of 1.62 − 0.68% by UV–Vis spectroscopy. • Higher lignin content strengthened mechanical properties of the hydrogel films. • Trace lignin affected the hydrogel morphology such as roughness and porosity. • High cell proliferation was observed in the hydrogel containing 1.68% lignin.

  3. Cytocompatible cellulose hydrogels containing trace lignin

    Energy Technology Data Exchange (ETDEWEB)

    Nakasone, Kazuki; Kobayashi, Takaomi, E-mail: takaomi@nagaoakut.ac.jp

    2016-07-01

    Sugarcane bagasse was used as a cellulose resource to prepare transparent and flexible cellulose hydrogel films. On the purification process from bagasse to cellulose, the effect of lignin residues in the cellulose was examined for the properties and cytocompatibility of the resultant hydrogel films. The cellulose was dissolved in lithium chloride/N,N-dimethylacetamide solution and converted to hydrogel films by phase inversion. In the purification process, sodium hydroxide (NaOH) treatment time was changed from 1 to 12 h. This resulted in cellulose hydrogel films having small amounts of lignin from 1.62 to 0.68%. The remaining lignin greatly affected hydrogel properties. Water content of the hydrogel films was increased from 1153 to 1525% with a decrease of lignin content. Moreover, lower lignin content caused weakening of tensile strength from 0.80 to 0.43 N/mm{sup 2} and elongation from 45.2 to 26.5%. Also, similar tendency was observed in viscoelastic behavior of the cellulose hydrogel films. Evidence was shown that the lignin residue was effective for the high strength of the hydrogel films. In addition, scanning probe microscopy in the morphological observation was suggested that the trace lignin in the cellulose hydrogel affected the cellulose fiber aggregation in the hydrogel network. The trace of lignin in the hydrogels also influenced fibroblast cell culture on the hydrogel films. The hydrogel film containing 1.68% lignin showed better fibroblast compatibility as compared to cell culture polystyrene dish used as reference. - Highlights: • Cellulose hydrogel films with trace lignin were obtained from sugarcane bagasse. • Lignin content was found to be in the range of 1.62 − 0.68% by UV–Vis spectroscopy. • Higher lignin content strengthened mechanical properties of the hydrogel films. • Trace lignin affected the hydrogel morphology such as roughness and porosity. • High cell proliferation was observed in the hydrogel containing 1.68% lignin.

  4. Energy conversion in polyelectrolyte hydrogels

    Science.gov (United States)

    Olvera de La Cruz, Monica; Erbas, Aykut; Olvera de la Cruz Team

    Energy conversion and storage have been an active field of research in nanotechnology parallel to recent interests towards renewable energy. Polyelectrolyte (PE) hydrogels have attracted considerable attention in this field due to their mechanical flexibility and stimuli-responsive properties. Ideally, when a hydrogel is deformed, applied mechanical work can be converted into electrostatic, elastic and steric-interaction energies. In this talk, we discuss the results of our extensive molecular dynamics simulations of PE hydrogels. We demonstrate that, on deformation, hydrogels adjust their deformed state predominantly by altering electrostatic interactions between their charged groups rather than excluded-volume and bond energies. This is due to the hydrogel's inherent tendency to preserve electro-neutrality in its interior, in combination with correlations imposed by backbone charges. Our findings are valid for a wide range of compression ratios and ionic strengths. The electrostatic-energy alterations that we observe in our MD simulations may induce pH or redox-potential changes inside the hydrogels. The resulting energetic difference can be harvested, for instance, analogously to a Carnot engine, or facilitated for sensor applications. Center for Bio-inspired Energy Science (CBES).

  5. Drying and storage effects on poly(ethylene glycol) hydrogel mechanical properties and bioactivity.

    Science.gov (United States)

    Luong, P T; Browning, M B; Bixler, R S; Cosgriff-Hernandez, E

    2014-09-01

    Hydrogels based on poly(ethylene glycol) (PEG) are increasingly used in biomedical applications because of their ability to control cell-material interactions by tuning hydrogel physical and biological properties. Evaluation of stability after drying and storage are critical in creating an off-the-shelf biomaterial that functions in vivo according to original specifications. However, there has not been a study that systematically investigates the effects of different drying conditions on hydrogel compositional variables. In the first part of this study, PEG-diacrylate hydrogels underwent common processing procedures (vacuum-drying, lyophilizing, hydrating then vacuum-drying), and the effect of this processing on the mechanical properties and swelling ratios was measured. Significant changes in compressive modulus, tensile modulus, and swelling ratio only occurred for select processed hydrogels. No consistent trends were observed after processing for any of the formulations tested. The effect of storage conditions on cell adhesion and spreading on collagen- and streptococcal collagen-like protein (Scl2-2)-PEG-diacrylamide hydrogels was then evaluated to characterize bioactivity retention after storage. Dry storage conditions preserved bioactivity after 6 weeks of storage; whereas, storage in PBS significantly reduced bioactivity. This loss of bioactivity was attributed to ester hydrolysis of the protein linker, acrylate-PEG-N-hydroxysuccinimide. These studies demonstrate that these processing methods and dry storage conditions may be used to prepare bioactive PEG hydrogel scaffolds with recoverable functionality after storage. © 2013 Wiley Periodicals, Inc.

  6. Antibacterial Properties of Silver Nanoparticles Embedded on Polyelectrolyte Hydrogels Based on α-Amino Acid Residues

    Directory of Open Access Journals (Sweden)

    Mario Casolaro

    2018-05-01

    Full Text Available Polyelectrolyte hydrogels bearing l-phenylalanine (PHE, l-valine (AVA, and l-histidine (Hist residues were used as scaffolds for the formation of silver nanoparticles by reduction of Ag+ ions with NaBH4. The interaction with the metal ion allowed a prompt collapse of the swollen hydrogel, due to the neutralization reaction of basic groups present on the polymer. The imidazole nitrogen of the hydrogel with Hist demonstrated greater complexing capacity with the Ag+ ion compared to the hydrogels with carboxyl groups. The subsequent reduction to metallic silver allowed for the restoration of the hydrogel’s degree of swelling to the starting value. Transmission electron microscopy (TEM and spectroscopic analyses showed, respectively, a uniform distribution of the 15 nm spherical silver nanoparticles embedded on the hydrogel and peak optical properties around a wavelength of 400 nm due to the surface plasmonic effect. Unlike native hydrogels, the composite hydrogels containing silver nanoparticles showed good antibacterial activity as gram+/gram− bactericides, and higher antifungal activity against S. cerevisiae.

  7. A Thixotropic Polyglycerol Sebacate-Based Supramolecular Hydrogel as an Injectable Drug Delivery Matrix

    Directory of Open Access Journals (Sweden)

    Hongye Ye

    2016-04-01

    Full Text Available We have developed a “self-healing” polyglycerol sebacate—polyethylene glycol methyl ether methacrylate (PGS-PEGMEMA/α-Cyclodextrin (αCD hydrogel which could be sheared into a liquid during injection and has the potential to quickly “heal” itself back into gel post-injection. This hydrogel was shown to be biocompatible and biodegradable and therefore appropriate for use in vivo. Furthermore, the storage and loss moduli of the hydrogels could be tuned (by varying the concentration of αCD between a fraction of a kPa to a few 100 kPa, a range that coincides with the moduli of cells and human soft tissues. This property would allow for this hydrogel to be used in vivo with maximal mechanical compatibility with human soft tissues. In vitro experiments showed that the hydrogel demonstrated a linear mass erosion profile and a biphasic drug (doxorubicin release profile: Phase I was primarily driven by diffusion and Phase II was driven by hydrogel erosion. The diffusion mechanism was modeled with the First Order equation and the erosion mechanism with the Hopfenberg equation. This established fitting model could be used to predict releases with other drugs and estimate the composition of the hydrogel required to achieve a desired release rate.

  8. Gamma ray-induced synthesis of hyaluronic acid/chondroitin sulfate-based hydrogels for biomedical applications

    International Nuclear Information System (INIS)

    Zhao, Linlin; Gwon, Hui-Jeong; Lim, Youn-Mook; Nho, Young-Chang; Kim, So Yeon

    2015-01-01

    Hyaluronic acid (HA)/chondroitin sulfate (CS)/poly(acrylic acid) (PAAc) hydrogel systems were synthesized by gamma-ray irradiation without the use of additional initiators or crosslinking agents to achieve a biocompatible hydrogel system for skin tissue engineering. HA and CS derivatives with polymerizable residues were synthesized. Then, the hydrogels composed of glycosaminoglycans, HA, CS, and a synthetic ionic polymer, PAAc, were prepared using gamma-ray irradiation through simultaneous free radical copolymerization and crosslinking. The physicochemical properties of the HA/CS/PAAc hydrogels having various compositions were investigated to evaluate their feasibility as artificial skin substitutes. The gel fractions of the HA/CS/PAAc hydrogels increased in absorbed doses up to 15 kGy, and they exhibited 91–93% gel fractions under 15 kGy radiation. All of the HA/CS/PAAc hydrogels exhibited relatively high water contents of over 90% and reached an equilibrium swelling state within 24 h. The enzymatic degradation kinetics of the HA/CS/PAAc hydrogels depended on both the concentration of the hyaluronidase solution and the ratio of HA/CS/PAAc. The in vitro drug release profiles of the HA/CS/PAAc hydrogels were significantly influenced by the interaction between the ionic groups in the hydrogels and the ionic drug molecules as well as the swelling of the hydrogels. From the cytotoxicity results of human keratinocyte (HaCaT) cells cultured with extracts of the HA/CS/PAAc hydrogels, all of the HA/CS/PAAc hydrogel samples tested showed relatively high cell viabilities of more than 82%, and did not induce any significant adverse effects on cell viability. - Highlights: • HA/CS/PAAc hydrogels were synthesized by gamma-ray irradiation. • HA/CS/PAAc hydrogels exhibited 91–93% gel fractions under 15 kGy radiation. • All of the HA/CS/PAAc hydrogels exhibited high water contents of over 90%. • The hydrogel samples showed relatively high cell viabilities of more than

  9. Hydrogels in Miniemulsions

    Science.gov (United States)

    Landfester, Katharina; Musyanovych, Anna

    In the last decade, the synthesis of polymeric materials that respond to specific environment stimuli by changing their size has attracted widespread interest in both fundamental and applied areas of research. Hydrogels in dispersions are composed of randomly oriented, physically or chemically crosslinked hydrophilic or amphiphilic polymer chains. The synthesis of these gels at the nanoscale (nanogels or microgels) is especially of great importance for their application in drug delivery and controlled release systems, and in biomimetics, biosensing, tissue regeneration, heterogeneous catalysis, etc. The focus of this review is to present the versatility of the miniemulsion process for the formation of monodisperse nanogels from synthetic and natural polymers. Several applications of the obtained microgels are briefly described.

  10. Mechano-responsive hydrogels crosslinked by reactive block copolymer micelles

    Science.gov (United States)

    Xiao, Longxi

    Hydrogels are crosslinked polymeric networks that can swell in water without dissolution. Owing to their structural similarity to the native extracelluar matrices, hydrogels have been widely used in biomedical applications. Synthetic hydrogels have been designed to respond to various stimuli, but mechanical signals have not incorporated into hydrogel matrices. Because most tissues in the body are subjected to various types of mechanical forces, and cells within these tissues have sophisticated mechano-transduction machinery, this thesis is focused on developing hydrogel materials with built-in mechano-sensing mechanisms for use as tissue engineering scaffolds or drug release devices. Self-assembled block copolymer micelles (BCMs) with reactive handles were employed as the nanoscopic crosslinkers for the construction of covalently crosslinked networks. BCMs were assembled from amphiphilic diblock copolymers of poly(n-butyl acrylate) and poly(acrylic acid) partially modified with acrylate. Radical polymerization of acrylamide in the presence of micellar crosslinkers gave rise to elastomeric hydrogels whose mechanical properties can be tuned by varying the BCM composition and concentration. TEM imaging revealed that the covalently integrated BCMs underwent strain-dependent reversible deformation. A model hydrophobic drug, pyrene, loaded into the core of BCMs prior to the hydrogel formation, was dynamically released in response to externally applied mechanical forces, through force-induced reversible micelle deformation and the penetration of water molecules into the micelle core. The mechano-responsive hydrogel has been studied for tissue repair and regeneration purposes. Glycidyl methacrylate (GMA)-modified hyaluronic acid (HA) was photochemically crosslinked in the presence of dexamethasone (DEX)-loaded crosslinkable BCMs. The resultant HA gels (HAxBCM) contain covalently integrated micellar compartments with DEX being sequestered in the hydrophobic core. Compared

  11. Photocrosslinkable Gelatin/Tropoelastin Hydrogel Adhesives for Peripheral Nerve Repair.

    Science.gov (United States)

    Soucy, Jonathan R; Shirzaei Sani, Ehsan; Portillo Lara, Roberto; Diaz, David; Dias, Felipe; Weiss, Anthony S; Koppes, Abigail N; Koppes, Ryan A; Annabi, Nasim

    2018-05-09

    Suturing peripheral nerve transections is the predominant therapeutic strategy for nerve repair. However, the use of sutures leads to scar tissue formation, hinders nerve regeneration, and prevents functional recovery. Fibrin-based adhesives have been widely used for nerve reconstruction, but their limited adhesive and mechanical strength and inability to promote nerve regeneration hamper their utility as a stand-alone intervention. To overcome these challenges, we engineered composite hydrogels that are neurosupportive and possess strong tissue adhesion. These composites were synthesized by photocrosslinking two naturally derived polymers, gelatin-methacryloyl (GelMA) and methacryloyl-substituted tropoelastin (MeTro). The engineered materials exhibited tunable mechanical properties by varying the GelMA/MeTro ratio. In addition, GelMA/MeTro hydrogels exhibited 15-fold higher adhesive strength to nerve tissue ex vivo compared to fibrin control. Furthermore, the composites were shown to support Schwann cell (SC) viability and proliferation, as well as neurite extension and glial cell participation in vitro, which are essential cellular components for nerve regeneration. Finally, subcutaneously implanted GelMA/MeTro hydrogels exhibited slower degradation in vivo compared with pure GelMA, indicating its potential to support the growth of slowly regenerating nerves. Thus, GelMA/MeTro composites may be used as clinically relevant biomaterials to regenerate nerves and reduce the need for microsurgical suturing during nerve reconstruction.

  12. High-water-content mouldable polyvinyl alcohol-borax hydrogels reinforced by well-dispersed cellulose nanoparticles: dynamic rheological properties and hydrogel formation mechanism.

    Science.gov (United States)

    Han, Jingquan; Lei, Tingzhou; Wu, Qinglin

    2014-02-15

    Cellulose nanoparticle (CNP) reinforced polyvinyl alcohol-borax (PB) hydrogels were produced via a facile approach in an aqueous system. The effects of particle size, aspect ratio, crystal structure, and surface charge of CNPs on the rheological properties of the composite hydrogels were investigated. The rheological measurements confirmed the incorporation of well-dispersed CNPs to PB system significantly enhanced the viscoelasticity and stiffness of hydrogels. The obtained free-standing, high elasticity and mouldable hydrogels exhibited self-recovery under continuous step strain and thermo-reversibility under temperature sweep. With the addition of cellulose I nanofibers, a 19-fold increase in the high-frequency plateau of storage modulus was obtained compared with that of the pure PB. CNPs acted as multifunctional crosslinking agents and nanofillers to physically and chemically bridge the 3D network hydrogel. The plausible mechanism for the multi-complexation between CNPs, polyvinyl alcohol and borax was proposed to understand the relationship between the 3D network and hydrogel properties. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

    International Nuclear Information System (INIS)

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

    2009-01-01

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

  14. Design and fabrication of a chitosan hydrogel with gradient structures via a step-by-step cross-linking process.

    Science.gov (United States)

    Xu, Yongxiang; Yuan, Shenpo; Han, Jianmin; Lin, Hong; Zhang, Xuehui

    2017-11-15

    The development of scaffolds to mimic the gradient structure of natural tissue is an important consideration for effective tissue engineering. In the present study, a physical cross-linking chitosan hydrogel with gradient structures was fabricated via a step-by-step cross-linking process using sodium tripolyphosphate and sodium hydroxide as sequential cross-linkers. Chitosan hydrogels with different structures (single, double, and triple layers) were prepared by modifying the gelling process. The properties of the hydrogels were further adjusted by varying the gelling conditions, such as gelling time, pH, and composition of the crosslinking solution. Slight cytotoxicity was showed in MTT assay for hydrogels with uncross-linking chitosan solution and non-cytotoxicity was showed for other hydrogels. The results suggest that step-by-step cross-linking represents a practicable method to fabricate scaffolds with gradient structures. Copyright © 2017. Published by Elsevier Ltd.

  15. A bioprintable form of chitosan hydrogel for bone tissue engineering.

    Science.gov (United States)

    Demirtaş, Tuğrul Tolga; Irmak, Gülseren; Gümüşderelioğlu, Menemşe

    2017-07-13

    Bioprinting can be defined as 3D patterning of living cells and other biologics by filling and assembling them using a computer-aided layer-by-layer deposition approach to fabricate living tissue and organ analogs for tissue engineering. The presence of cells within the ink to use a 'bio-ink' presents the potential to print 3D structures that can be implanted or printed into damaged/diseased bone tissue to promote highly controlled cell-based regeneration and remineralization of bone. In this study, it was shown for the first time that chitosan solution and its composite with nanostructured bone-like hydroxyapatite (HA) can be mixed with cells and printed successfully. MC3T3-E1 pre-osteoblast cell laden chitosan and chitosan-HA hydrogels, which were printed with the use of an extruder-based bioprinter, were characterized by comparing these hydrogels to alginate and alginate-HA hydrogels. Rheological analysis showed that all groups had viscoelastic properties. It was also shown that under simulated physiological conditions, chitosan and chitosan-HA hydrogels were stable. Also, the viscosity values of the bio-solutions were in an applicable range to be used in 3D bio-printers. Cell viability and proliferation analyses documented that after printing with bio-solutions, cells continued to be viable in all groups. It was observed that cells printed within chitosan-HA composite hydrogel had peak expression levels for early and late stages osteogenic markers. It was concluded that cells within chitosan and chitosan-HA hydrogels had mineralized and differentiated osteogenically after 21 days of culture. It was also discovered that chitosan is superior to alginate, which is the most widely used solution preferred in bioprinting systems, in terms of cell proliferation and differentiation. Thus, applicability and printability of chitosan as a bio-printing solution were clearly demonstrated. Furthermore, it was proven that the presence of bone-like nanostructured HA in

  16. Flexible pH-Sensing Hydrogel Fibers for Epidermal Applications.

    Science.gov (United States)

    Tamayol, Ali; Akbari, Mohsen; Zilberman, Yael; Comotto, Mattia; Lesha, Emal; Serex, Ludovic; Bagherifard, Sara; Chen, Yu; Fu, Guoqing; Ameri, Shideh Kabiri; Ruan, Weitong; Miller, Eric L; Dokmeci, Mehmet R; Sonkusale, Sameer; Khademhosseini, Ali

    2016-03-01

    Epidermal pH is an indication of the skin's physiological condition. For example, pH of wound can be correlated to angiogenesis, protease activity, bacterial infection, etc. Chronic nonhealing wounds are known to have an elevated alkaline environment, while healing process occurs more readily in an acidic environment. Thus, dermal patches capable of continuous pH measurement can be used as point-of-care systems for monitoring skin disorder and the wound healing process. Here, pH-responsive hydrogel fibers are presented that can be used for long-term monitoring of epidermal wound condition. pH-responsive dyes are loaded into mesoporous microparticles and incorporated into hydrogel fibers using a microfluidic spinning system. The fabricated pH-responsive microfibers are flexible and can create conformal contact with skin. The response of pH-sensitive fibers with different compositions and thicknesses are characterized. The suggested technique is scalable and can be used to fabricate hydrogel-based wound dressings with clinically relevant dimensions. Images of the pH-sensing fibers during real-time pH measurement can be captured with a smart phone camera for convenient readout on-site. Through image processing, a quantitative pH map of the hydrogel fibers and the underlying tissue can be extracted. The developed skin dressing can act as a point-of-care device for monitoring the wound healing process. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Polymers in the gut compress the colonic mucus hydrogel.

    Science.gov (United States)

    Datta, Sujit S; Preska Steinberg, Asher; Ismagilov, Rustem F

    2016-06-28

    Colonic mucus is a key biological hydrogel that protects the gut from infection and physical damage and mediates host-microbe interactions and drug delivery. However, little is known about how its structure is influenced by materials it comes into contact with regularly. For example, the gut abounds in polymers such as dietary fibers or administered therapeutics, yet whether such polymers interact with the mucus hydrogel, and if so, how, remains unclear. Although several biological processes have been identified as potential regulators of mucus structure, the polymeric composition of the gut environment has been ignored. Here, we demonstrate that gut polymers do in fact regulate mucus hydrogel structure, and that polymer-mucus interactions can be described using a thermodynamic model based on Flory-Huggins solution theory. We found that both dietary and therapeutic polymers dramatically compressed murine colonic mucus ex vivo and in vivo. This behavior depended strongly on both polymer concentration and molecular weight, in agreement with the predictions of our thermodynamic model. Moreover, exposure to polymer-rich luminal fluid from germ-free mice strongly compressed the mucus hydrogel, whereas exposure to luminal fluid from specific-pathogen-free mice-whose microbiota degrade gut polymers-did not; this suggests that gut microbes modulate mucus structure by degrading polymers. These findings highlight the role of mucus as a responsive biomaterial, and reveal a mechanism of mucus restructuring that must be integrated into the design and interpretation of studies involving therapeutic polymers, dietary fibers, and fiber-degrading gut microbes.

  18. In Situ Mineralization of Magnetite Nanoparticles in Chitosan Hydrogel

    Science.gov (United States)

    Wang, Yongliang; Li, Baoqiang; Zhou, Yu; Jia, Dechang

    2009-09-01

    Based on chelation effect between iron ions and amino groups of chitosan, in situ mineralization of magnetite nanoparticles in chitosan hydrogel under ambient conditions was proposed. The chelation effect between iron ions and amino groups in CS-Fe complex, which led to that chitosan hydrogel exerted a crucial control on the magnetite mineralization, was proved by X-ray photoelectron spectrum. The composition, morphology and size of the mineralized magnetite nanoparticles were characterized by X-ray diffraction, Raman spectroscopy, transmission electron microscopy and thermal gravity. The mineralized nanoparticles were nonstoichiometric magnetite with a unit formula of Fe2.85O4 and coated by a thin layer of chitosan. The mineralized magnetite nanoparticles with mean diameter of 13 nm dispersed in chitosan hydrogel uniformly. Magnetization measurement indicated that superparamagnetism behavior was exhibited. These magnetite nanoparticles mineralized in chitosan hydrogel have potential applications in the field of biotechnology. Moreover, this method can also be used to synthesize other kinds of inorganic nanoparticles, such as ZnO, Fe2O3 and hydroxyapatite.

  19. In Situ Mineralization of Magnetite Nanoparticles in Chitosan Hydrogel

    Directory of Open Access Journals (Sweden)

    Wang Yongliang

    2009-01-01

    Full Text Available Abstract Based on chelation effect between iron ions and amino groups of chitosan, in situ mineralization of magnetite nanoparticles in chitosan hydrogel under ambient conditions was proposed. The chelation effect between iron ions and amino groups in CS–Fe complex, which led to that chitosan hydrogel exerted a crucial control on the magnetite mineralization, was proved by X-ray photoelectron spectrum. The composition, morphology and size of the mineralized magnetite nanoparticles were characterized by X-ray diffraction, Raman spectroscopy, transmission electron microscopy and thermal gravity. The mineralized nanoparticles were nonstoichiometric magnetite with a unit formula of Fe2.85O4and coated by a thin layer of chitosan. The mineralized magnetite nanoparticles with mean diameter of 13 nm dispersed in chitosan hydrogel uniformly. Magnetization measurement indicated that superparamagnetism behavior was exhibited. These magnetite nanoparticles mineralized in chitosan hydrogel have potential applications in the field of biotechnology. Moreover, this method can also be used to synthesize other kinds of inorganic nanoparticles, such as ZnO, Fe2O3and hydroxyapatite.

  20. Hydrogels for precision meniscus tissue engineering: a comprehensive review.

    Science.gov (United States)

    Rey-Rico, Ana; Cucchiarini, Magali; Madry, Henning

    The meniscus plays a pivotal role to preserve the knee joint homeostasis. Lesions to the meniscus are frequent, have a reduced ability to heal, and may induce tibiofemoral osteoarthritis. Current reconstructive therapeutic options mainly focus on the treatment of lesions in the peripheral vascularized region. In contrast, few approaches are capable of stimulating repair of damaged meniscal tissue in the central, avascular portion. Tissue engineering approaches are of high interest to repair or replace damaged meniscus tissue in this area. Hydrogel-based biomaterials are of special interest for meniscus repair as its inner part contains relatively high proportions of proteoglycans which are responsible for the viscoelastic compressive properties and hydration grade. Hydrogels exhibiting high water content and providing a specific three-dimensional (3D) microenvironment may be engineered to precisely resemble this topographical composition of the meniscal tissue. Different polymers of both natural and synthetic origins have been manipulated to produce hydrogels hosting relevant cell populations for meniscus regeneration and provide platforms for meniscus tissue replacement. So far, these compounds have been employed to design controlled delivery systems of bioactive molecules involved in meniscal reparative processes or to host genetically modified cells as a means to enhance meniscus repair. This review describes the most recent advances on the use of hydrogels as platforms for precision meniscus tissue engineering.

  1. Macroporous modified poly (vinyl alcohol) hydrogels with charged groups for tissue engineering: Preparation and in vitro evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Drozdova, Maria G., E-mail: drozdovamg@gmail.com [Polymers for Biology Laboratory, Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry of Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, Moscow 117997 (Russian Federation); Zaytseva-Zotova, Daria S. [Polymers for Biology Laboratory, Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry of Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, Moscow 117997 (Russian Federation); Akasov, Roman A. [Polymers for Biology Laboratory, Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry of Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, Moscow 117997 (Russian Federation); Sechenov First Moscow State Medical University, Institute for Regenerative Medicine, Trubetskaya str., 8/2, Moscow 119048 (Russian Federation); Golunova, Anna S.; Artyukhov, Alexander A. [D. Mendeleyev University of Chemical Technology of Russia, Miusskaya Square 9, Moscow 125047 (Russian Federation); Udartseva, Olga O.; Andreeva, Elena R. [Institute of Biomedical Problems of Russian Academy of Sciences, Khoroshevskoe Shosse 76a, Moscow 123007 (Russian Federation); Lisovyy, Denis E.; Shtilman, Michael I. [D. Mendeleyev University of Chemical Technology of Russia, Miusskaya Square 9, Moscow 125047 (Russian Federation); Markvicheva, Elena A. [Polymers for Biology Laboratory, Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry of Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, Moscow 117997 (Russian Federation)

    2017-06-01

    Poly(vinyl alcohol) (PVA) hydrogels are widely employed for various biomedical applications, including tissue engineering, due to their biocompatibility, high water solubility, low protein adsorption, and chemical stability. However, non-charged surface of PVA-based hydrogels is not optimal for cell adhesion and spreading. Here, cross-linked macroporous hydrogels based on low molecular weight acrylated PVA (Acr-PVA) was synthesized by modification of the pendant alcohol groups on the PVA with glycidyl methacrylate (GMA). To enhance cell affinity, charged groups were introduced to the hydrogel composition. For this purpose, Acr-PVA was copolymerized with either negatively charged acrylic acid (AA) or positively charged 2-(diethylamino) ethyl methacrylate (DEAEMA) monomers. A surface charge of the obtained hydrogels was found to be in function of the co-monomer type and content. Confocal microscopy observations confirmed that adhesion and spreading of both mouse fibroblasts (L929) and human mesenchymal stem cells (hMSC) on the modified Acr-PVA-AA and Acr-PVA-DEAEMA hydrogels were better than those on the non-modified Acr-PVA hydrogel. The increase of DEAEMA monomer content from 5 to 15 mol% resulted in the enhancement of cell viability which was 1.5-fold higher for Acr-PVA-DEAEMA-15 hydrogel than that of the non-modified Acr-PVA hydrogel sample. - Highlights: • To enhance cell affinity, acrylated PVA hydrogel was modified with AA or DEAEMA monomers. • Cell adhesion and spreading were found to depend on the co-monomer type and content. • Proliferation of L929 fibroblasts and stem cells increased on the modified hydrogels.

  2. Macroporous modified poly (vinyl alcohol) hydrogels with charged groups for tissue engineering: Preparation and in vitro evaluation

    International Nuclear Information System (INIS)

    Drozdova, Maria G.; Zaytseva-Zotova, Daria S.; Akasov, Roman A.; Golunova, Anna S.; Artyukhov, Alexander A.; Udartseva, Olga O.; Andreeva, Elena R.; Lisovyy, Denis E.; Shtilman, Michael I.; Markvicheva, Elena A.

    2017-01-01

    Poly(vinyl alcohol) (PVA) hydrogels are widely employed for various biomedical applications, including tissue engineering, due to their biocompatibility, high water solubility, low protein adsorption, and chemical stability. However, non-charged surface of PVA-based hydrogels is not optimal for cell adhesion and spreading. Here, cross-linked macroporous hydrogels based on low molecular weight acrylated PVA (Acr-PVA) was synthesized by modification of the pendant alcohol groups on the PVA with glycidyl methacrylate (GMA). To enhance cell affinity, charged groups were introduced to the hydrogel composition. For this purpose, Acr-PVA was copolymerized with either negatively charged acrylic acid (AA) or positively charged 2-(diethylamino) ethyl methacrylate (DEAEMA) monomers. A surface charge of the obtained hydrogels was found to be in function of the co-monomer type and content. Confocal microscopy observations confirmed that adhesion and spreading of both mouse fibroblasts (L929) and human mesenchymal stem cells (hMSC) on the modified Acr-PVA-AA and Acr-PVA-DEAEMA hydrogels were better than those on the non-modified Acr-PVA hydrogel. The increase of DEAEMA monomer content from 5 to 15 mol% resulted in the enhancement of cell viability which was 1.5-fold higher for Acr-PVA-DEAEMA-15 hydrogel than that of the non-modified Acr-PVA hydrogel sample. - Highlights: • To enhance cell affinity, acrylated PVA hydrogel was modified with AA or DEAEMA monomers. • Cell adhesion and spreading were found to depend on the co-monomer type and content. • Proliferation of L929 fibroblasts and stem cells increased on the modified hydrogels.

  3. Fabrication of Self-Healable and Patternable Polypyrrole/Agarose Hybrid Hydrogels for Smart Bioelectrodes.

    Science.gov (United States)

    Park, Nokyoung; Chae, Seung Chul; Kim, Il Tae; Hur, Jaehyun

    2016-02-01

    We present a new class of electrically conductive, mechanically moldable, and thermally self-healable hybrid hydrogels. The hybrid gels consist of polypyrrole and agarose as the conductive component and self-healable matrix, respectively. By using the appropriate oxidizing agent under conditions of mild temperature, the polymerization of pyrrole occurred along the three-dimensional network of the agarose hydrogel matrix. In contrast to most commercially available hydrogels, the physical crosslinking of agarose gel allows for reversible gelation in the case of our hybrid gel, which could be manipulated by temperature variation, which controls the electrical on/off behavior of the hybrid gel electrode. Exploiting this property, we fabricated a hybrid conductive hydrogel electrode which also self-heals thermally. The novel composite material we report here will be useful for many technological and biological applications, especially in reactive biomimetic functions and devices, artificial muscles, smart membranes, smart full organic batteries, and artificial chemical synapses.

  4. Modeling programmable deformation of self-folding all-polymer structures with temperature-sensitive hydrogels

    International Nuclear Information System (INIS)

    Guo, Wei; Zhou, Jinxiong; Li, Meie

    2013-01-01

    Combination of soft active hydrogels with hard passive polymers gives rise to all-polymer composites. The hydrogel is sensitive to external stimuli while the passive polymer is inert. Utilizing the different behaviors of two materials subject to environmental variation, for example temperature, results in self-folding soft machines. We report our efforts to model the programmable deformation of self-folding structures with temperature-sensitive hydrogels. The self-folding structures are realized either by constructing a bilayer structure or by incorporating hydrogels as hinges. The methodology and the results may aid the design, control and fabrication of 3D complex structures from 2D simple configurations through self-assembly. (paper)

  5. Performance evaluation of nanoclay enriched anti-microbial hydrogels for biomedical applications

    Directory of Open Access Journals (Sweden)

    Sonali Karnik

    2016-02-01

    Full Text Available A major factor contributing to the failure of orthopedic and orthodontic implants is post-surgical infection. Coating metallic implant surfaces with anti-microbial agents has shown promise but does not always prevent the formation of bacterial biofilms. Furthermore, breakdown of these coatings within the human body can cause release of the anti-microbial drugs in an uncontrolled or unpredictable fashion. In this study, we used a calcium alginate and calcium phosphate cement (CPC hydrogel composite as the base material and enriched these hydrogels with the anti-microbial drug, gentamicin sulfate, loaded within a halloysite nanotubes (HNTs. Our results demonstrate a sustained and extended release of gentamicin from hydrogels enriched with the gentamicin-loaded HNTs. When tested against the gram-negative bacteria, the hydrogel/nanoclay composites showed a pronounced zone of inhibition suggesting that anti-microbial doped nanoclay enriched hydrogels can prevent the growth of bacteria. The release of gentamicin sulfate for a period of five days from the nanoclay-enriched hydrogels would supply anti-microbial agents in a sustained and controlled manner and assist in preventing microbial growth and biofilm formation on the titanium implant surface. A pilot study, using mouse osteoblasts, confirmed that the nanoclay enriched surfaces are also cell supportive as osteoblasts readily, proliferated and produced a type I collagen and proteoglycan matrix.

  6. Genipin-cross-linked poly(L-lysine)-based hydrogels: synthesis, characterization, and drug encapsulation.

    Science.gov (United States)

    Wang, Steven S S; Hsieh, Ping-Lun; Chen, Pei-Shan; Chen, Yu-Tien; Jan, Jeng-Shiung

    2013-11-01

    Genipin-cross-linked hydrogels composed of biodegradable and pH-sensitive cationic poly(L-lysine) (PLL), poly(L-lysine)-block-poly(L-alanine) (PLL-b-PLAla), and poly(L-lysine)-block-polyglycine (PLL-b-PGly) polypeptides were synthesized, characterized, and used as carriers for drug delivery. These polypeptide hydrogels can respond to pH-stimulus and their gelling and mechanical properties, degradation rate, and drug release behavior can be tuned by varying polypeptide composition and cross-linking degree. Comparing with natural polymers, the synthetic polypeptides with well-defined chain length and composition can warrant the preparation of the hydrogels with tunable properties to meet the criteria for specific biomedical applications. These hydrogels composed of natural building blocks exhibited good cell compatibility and enzyme degradability and can support cell attachment/proliferation. The evaluation of these hydrogels for in vitro drug release revealed that the controlled release profile was a biphasic pattern with a mild burst release and a moderate release rate thereafter, suggesting the drug molecules were encapsulated inside the gel matrix. With the versatility of polymer chemistry and conjugation of functional moieties, it is expected these hydrogels can be useful for biomedical applications such as polymer therapeutics and tissue engineering. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Novel Hydrogels from Renewable Resources

    Science.gov (United States)

    Karaaslan, Muzafer Ahmet

    2011-12-01

    The cell wall of most plant biomass from forest and agricultural resources consists of three major polymers, cellulose, hemicellulose and lignin. Of these, hemicelluloses have gained increasing attention as sustainable raw materials. In the first part of this study, novel pH-sensitive semi-IPN hydrogels based on hemicelluloses and chitosan were prepared using glutaraldehyde as the crosslinking agent. The hemicellulose isolated from aspen was analyzed for sugar content by HPLC, and its molecular weight distribution was determined by high performance size exclusion chromatography. Results revealed that hemicellulose had a broad molecular weight distribution with a fair amount of polymeric units, together with xylose, arabinose and glucose. The effect of hemicellulose content on mechanical properties and swelling behavior of hydrogels were investigated. The semi-IPNs hydrogel structure was confirmed by FT-IR, X-ray study and ninhydrin assay method. X-ray analysis showed that higher hemicellulose contents yielded higher crystallinity. Mechanical properties were mainly dependent on the crosslink density and average molecular weight between crosslinks. Swelling ratios increased with increasing hemicellulose content and were high at low pH values due to repulsion between similarly charged groups. In vitro release study of a model drug showed that these semi-IPN hydrogels could be used for controlled drug delivery into gastric fluid. The aim of the second part of this study was to control the crosslink density and the mechanical properties of hemicellulose/chitosan semi-IPN hydrogels by changing the crosslinking sequence. It has been hypothesized that by performing the crosslinking step before introducing hemicellulose, covalent crosslinking of chitosan would not be hindered and therefore more and/or shorter crosslinks could be formed. Furthermore, additional secondary interactions and crystalline domains introduced through hemicellulose could be favorable in terms of

  8. Carbon Nanotubes Hybrid Hydrogels in Drug Delivery: A Perspective Review

    Science.gov (United States)

    Hampel, Silke; Spizzirri, Umile Gianfranco; Parisi, Ortensia Ilaria; Picci, Nevio; Iemma, Francesca

    2014-01-01

    The use of biologics, polymers, silicon materials, carbon materials, and metals has been proposed for the preparation of innovative drug delivery devices. One of the most promising materials in this field are the carbon-nanotubes composites and hybrid materials coupling the advantages of polymers (biocompatibility and biodegradability) with those of carbon nanotubes (cellular uptake, stability, electromagnatic, and magnetic behavior). The applicability of polymer-carbon nanotubes composites in drug delivery, with particular attention to the controlled release by composites hydrogel, is being extensively investigated in the present review. PMID:24587993

  9. Anisotropic dehydration of hydrogel surfaces.

    Science.gov (United States)

    Kaklamani, Georgia; Cheneler, David; Grover, Liam M; Adams, Michael J; Anastasiadis, Spiros H; Bowen, James

    2017-12-01

    Efforts to develop tissue-engineered skin for regenerative medicine have explored natural, synthetic, and hybrid hydrogels. The creation of a bilayer material, with the stratification exhibited by native skin, is a complex problem. The mechanically robust, waterproof epidermis presents the stratum corneum at the tissue/air interface, which confers many of these protective properties. In this work, we explore the effect of high temperatures on alginate hydrogels, which are widely employed for tissue engineering due to their excellent mechanical properties and cellular compatibility. In particular, we investigate the rapid dehydration of the hydrogel surface which occurs following local exposure to heated surfaces with temperatures in the range 100-200 °C. We report the creation of a mechanically strengthened hydrogel surface, with improved puncture resistance and increased coefficient of friction, compared to an unheated surface. The use of a mechanical restraint during heating promoted differences in the rate of mass loss; the rate of temperature increase within the hydrogel, in the presence and absence of restraint, is simulated and discussed. It is hoped that the results will be of use in the development of processes suitable for preparing skin-like analogues; application areas could include wound healing and skin restoration.

  10. A Bioinspired Alginate-Gum Arabic Hydrogel with Micro-/Nanoscale Structures for Controlled Drug Release in Chronic Wound Healing.

    Science.gov (United States)

    Li, Mi; Li, Haichang; Li, Xiangguang; Zhu, Hua; Xu, Zihui; Liu, Lianqing; Ma, Jianjie; Zhang, Mingjun

    2017-07-12

    Biopolymeric hydrogels have drawn increasing research interest in biomaterials due to their tunable physical and chemical properties for both creating bioactive cellular microenvironment and serving as sustainable therapeutic reagents. Inspired by a naturally occurring hydrogel secreted from the carnivorous Sundew plant for trapping insects, here we have developed a bioinspired hydrogel to deliver mitsugumin 53 (MG53), an important protein in cell membrane repair, for chronic wound healing. Both chemical compositions and micro-/nanomorphological properties inherent from the natural Sundew hydrogel were mimicked using sodium alginate and gum arabic with calcium ion-mediated cross-linking. On the basis of atomic force microscopy (AFM) force measurements, an optimal sticky hydrogel scaffold was obtained through orthogonal experimental design. Imaging and mechanical analysis showed the distinct correlation between structural morphology, adhesion characteristics, and mechanical properties of the Sundew-inspired hydrogel. Combined characterization and biochemistry techniques were utilized to uncover the underlying molecular composition involved in the interactions between hydrogel and protein. In vitro drug release experiments confirmed that the Sundew-inspired hydrogel had a biphasic-kinetics release, which can facilitate both fast delivery of MG53 for improving the reepithelization process of the wounds and sustained release of the protein for treating chronic wounds. In vivo experiments showed that the Sundew-inspired hydrogel encapsulating with rhMG53 could facilitate dermal wound healing in mouse model. Together, these studies confirmed that the Sundew-inspired hydrogel has both tunable micro-/nanostructures and physicochemical properties, which enable it as a delivery vehicle for chronic wounding healing. The research may provide a new way to develop biocompatible and tunable biomaterials for sustainable drug release to meet the needs of biological activities.

  11. Radiation induced variations in photoperiod-sensitivity, thermo-sensitivity and the number of days to heading in rice

    International Nuclear Information System (INIS)

    Hsieh, S.C.

    1975-01-01

    Radiation induced semi-dwarf mutants derived from five japonica type varieties of rice were studied with regard to their photoperiod-sensitivity, thermo-sensitivity and the number of days to heading. The experiment was carried out under the natural conditions at Taipei. The coefficient of photoperiod-sensitivity and thermo-sensitivity as developed by Oka (1954) were estimated for the mutants in comparison with their original varieties. It was observed that these various physiological characters could be altered easily by mutations. Mutants showed wider ranges in both positive and negative directions than their original varieties in all physiological characters studied. Even though heading date depends on both photoperiod-sensitivity and thermo-sensitivity, it was estimated which of the two contributed more to the induced earliness in each mutant. This offers a basis for selecting early maturing lines of rice

  12. The influence of increased cross-linker chain length in thermosensitive microspheres on potential sun-protection activity.

    Science.gov (United States)

    Musiał, Witold; Kokol, Vanja; Voncina, Bojana

    2010-01-01

    The sun protection should involve substances with protecting activity against both UVB and UVA radiation. In this research the evaluation of thermosensitive microspheres as potential molecules for sunscreen formulations was approached, using modified Boots star rating system. The microspheres, thermosensitive N-isopropylacrylamide derivatives, have potential protecting activity against UV radiation. The MX and DX microspheres, with ethylene glycol dimethacrylate and diethylene glycol dimethacrylate crosslinker respectively, due to theirs thermosensitivity exhibit increase in protecting activity against UV radiation when heated to 45 degrees C. The MX microspheres have higher increase in terms of UV absorbance, comparing to DX microspheres, when heated in the 25 degrees C to 45 degrees C range. Studied microspheres have high potential for application as components of sun-screens used in elevated temperatures.

  13. Type II collagen-hyaluronan hydrogel – a step towards a scaffold for intervertebral disc tissue engineering

    Directory of Open Access Journals (Sweden)

    L Calderon

    2010-09-01

    Full Text Available Intervertebral disc regeneration strategies based on stem cell differentiation in combination with the design of functional scaffolds is an attractive approach towards repairing/regenerating the nucleus pulposus. The specific aim of this study was to optimise a composite hydrogel composed of type II collagen and hyaluronic acid (HA as a carrier for mesenchymal stem cells. Hydrogel stabilisation was achieved by means of 1-ethyl-3(3-dimethyl aminopropyl carbodiimide (EDC and N-hydroxysuccinimide (NHS cross-linking. Optimal hydrogel properties were determined by investigating different concentrations of EDC (8mM, 24mM and 48mM. Stable hydrogels were obtained independent of the concentration of carbodiimide used. The hydrogels cross-linked by the lowest concentration of EDC (8mM demonstrated high swelling properties. Additionally, improved proliferation of seeded rat mesenchymal stem cells (rMSCs and hydrogel stability levels in culture were observed with this 8mM cross-linked hydrogel. Results from this study indicate that EDC/NHS (8mM cross-linked type II collagen/HA hydrogel was capable of supporting viability of rMSCs, and furthermore their differentiation into a chondrogenic lineage. Further investigations should be conducted to determine its potential as scaffold for nucleus pulposus regeneration/repair.

  14. Radiation synthesis and characterization of pH-sensitive poly(acrylic acid-co-N-vinyl-2-pyrrolidone) hydrogels

    International Nuclear Information System (INIS)

    Yang Mingcheng; Zhu Jun; Song Weidong; Song Hongyan; Zhu Chengshen

    2006-01-01

    Hydrogels are crosslinked, three-dimensional hydrophilic polymer networks that swell but do not dissolve when brought into contact with water. These materials have been investigated extensively for potential applications in the biomedical field because of their similarities to soft tissues and their good tissue and blood compatibility. More specifically, pH-sensitive hydrogels are used for sustained gastro-intestinal drug delivery systems due to the intimacy and extended duration of contact. In this work, pH-sensitive copolymer hydrogels were prepared using acrylic acid and N-vinyl-2-pyrrolidone by γ-ray irradiation at ambient temperature. Effects of dose, monomer concentration, monomer composition, temperature and pH on the swelling ratio (SR) of the copolymer hydrogels were investigated in detail. The results show that SR of the copolymer hydrogels decreases with the monomer concentration and with the increase of absorbed dose. These copolymer hydrogels show good pH-sensitive behavior. These material shows no noticeable change in swelling at lower pH (pH<4) but an abrupt increase in swelling at higher pH (from pH7 to pH9.8). At pH 1.4, the SR of the copolymer hydrogels increases with the temperature. To the contrary, at pH 9.8, the SR of the copolymer hydrogels decreases with the temperature. (authors)

  15. Hydrogels from feather keratin show higher viscoelastic properties and cell proliferation than those from hair and wool keratins.

    Science.gov (United States)

    Esparza, Yussef; Bandara, Nandika; Ullah, Aman; Wu, Jianping

    2018-09-01

    Hydrogel prepared from keratin shows potential applications in tissue engineering. However, the importance of the keratin sources has not been considered. The objectives of this study were to characterize and compare the rheological (storage modulus), physical (porosity, pore size, swelling capacity, and water contact angle) and in vitro cell compatibility of hydrogel scaffolds prepared from various keratin sources. Keratins were characterized by means of their molecular weight, amino acid composition, thermal and conformational properties. Hydrogels from chicken feather keratins demonstrated substantially higher storage modulus (G') than hair and wool keratin hydrogels. However, higher swelling capacity (>3000%) was determined in hair and wool over feather keratin (1500%) hydrogels. Our results suggest that small molecular weight and β-sheet conformation of feather keratin (~10 kDa) facilitated the self-assembly of rigid hydrogels through disulfide bond re-oxidation. Whereas, high molecular weight (10-75 kDa) stretchable α-helix conformation in hair and wool keratins resulted in weaker hydrogels. The cell cultures using fibroblasts showed the highest proliferation rate on chicken feather keratin hydrogel scaffolds. After 15 days of culture, partial breakdown of keratin fibers was observed. Results indicate that stiffer avian keratins can be used to fabricate more mechanically robust biomaterials than mammalian keratins. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Electrochemical characterization of hydrogels for biomimetic applications

    DEFF Research Database (Denmark)

    Peláez, L.; Romero, V.; Escalera, S.

    2011-01-01

    ) or a photoinitiator (P) to encapsulate and stabilize biomimetic membranes for novel separation technologies or biosensor applications. In this paper, we have investigated the electrochemical properties of the hydrogels used for membrane encapsulation. Specifically, we studied the crosslinked hydrogels by using...... electrochemical impedance spectroscopy (EIS), and we demonstrated that chemically crosslinked hydrogels had lower values for the effective electrical resistance and higher values for the electrical capacitance compared with hydrogels with photoinitiated crosslinking. Transport numbers were obtained using......〉 and 〈Pw〉 values than PEG‐1000‐DMA‐P and PEG‐400‐DA‐P hydrogels. In conclusion, our results show that hydrogel electrochemical properties can be controlled by the choice of polymer and type of crosslinking used and that their water and salt permeability properties are congruent with the use of hydrogels...

  17. [Thromboresistance of glucose-containing hydrogels].

    Science.gov (United States)

    Valuev, I L; Valuev, L I; Vanchugova, L V; Obydennova, I V; Valueva, T A

    2013-01-01

    The thromboresistance of glucose-sensitive polymer hydrogels, modeling one of the functions of the pancreas, namely, the ability to secrete insulin in response to the introduction of glucose into the environment, has been studied. Hydrogels were synthesized by the copolymerization of hydroxyethyl methacrylate with N-acryloyl glucosamine in the presence of a cross-linking agent and subsequently treated with concanavalin A. Introduction of glucose residues into the hydrogel did not result in significant changes in either the number of trombocytes adhered to the hydrogel or the degree of denaturation of blood plasma proteins interacting with the hydrogel. Consequently, the biological activity of insulin did not change after release from the hydrogel. The use of glucose-sensitive hydrogels is supposed to contribute to the development of a novel strategy for the treatment of diabetes.

  18. Design and synthesis study of the thermo-sensitive poly (N-vinylpyrrolidone-b- N, N-diethylacrylamide).

    Science.gov (United States)

    Zhang, Xiayun; Yang, Zhongduo; Xie, Dengmin; Liu, Donglei; Chen, Zhenbin; Li, Ke; Li, Zhizhong; Tichnell, Brandon; Liu, Zhen

    2018-01-01

    The reversible addition fragmentation chain transfer (RAFT) polymerization method was adopted here to prepare a series of thermo-sensitive copolymers, poly (N,N-diethyl- acrylamide-b-N-vinylpyrrolidone). Their structures, molecular weight distribution and temperature sensitivity performances were characterized by the nuclear magnetic resonance ( 1 HNMR), the gel permeation chromatography (GPC) and the fluorescence spectrophotometer, respectively. It has been identified that the synthesis reaction of the block copolymer was living polymerization. The thermo-sensitivity study suggested that N-vinylpyrrolidone (NVP), played a key role on the lower critical solution temperature (LCST) performance.

  19. Hydrogels and their medical applications

    Science.gov (United States)

    Rosiak, Janusz M.; Yoshii, Fumio

    1999-05-01

    Biomaterials play a key role in most approaches for engineering tissues as substitutes for functional replacement, for components of devices related to therapy and diagnosis, for drug delivery systems and supportive scaffolds for guided tissue growth. Modern biomaterials could be composed of various components, e.g. metals, ceramics, natural tissues, polymers. In this last group, the hydrogels, hydrophilic polymeric gels with requested biocompatibility and designed interaction with living surrounding seem to be one of the most promising group of biomaterials. Especially, if they are formed by means of ionizing radiation. In early 1950s, the pioneers of the radiation chemistry of polymers began some experiments with radiation crosslinking of hydrophilic polymers. However, hydrogels were analyzed mainly from the point of view of the phenomenon associated with radiation synthesis, with topology of network and relation between radiation parameters of the processes. Fundamental monographs on radiation polymer physics and chemistry written by A. Charlesby (Atomic Radition and polymers, Pergamon Press, Oxford, 1960) and A. Chapiro (Radiation Chemistry of Polymeric Systems, Interscience, New York, 1962) proceed from this time. The noticeable interest in the application of radiation techniques to obtain hydrogels for biomedical purposes began in the late sixties as a result of the papers and patents invented by Japanese and American scientists, headed by Kaetsu in Japan and Hoffman in USA. Immobilization of biologically active species in hydrogel matrices, their use as drug delivery systems and enzyme traps as well as the modification of material surfaces to improve biocompatibility and their ability to bond antigens and antibodies had been the main subjects of these investigations. In this article a brief summary of investigations on mechanism and kinetics of radiation formation of hydrogels as well as some examples of commercialized hydrogel biomaterials have been

  20. Hydrogels and their medical applications

    International Nuclear Information System (INIS)

    Rosiak, Janusz M.; Yoshii, Fumio

    1999-01-01

    Biomaterials play a key role in most approaches for engineering tissues as substitutes for functional replacement, for components of devices related to therapy and diagnosis, for drug delivery systems and supportive scaffolds for guided tissue growth. Modern biomaterials could be composed of various components, e.g. metals, ceramics, natural tissues, polymers. In this last group, the hydrogels, hydrophilic polymeric gels with requested biocompatibility and designed interaction with living surrounding seem to be one of the most promising group of biomaterials. Especially, if they are formed by means of ionizing radiation. In early 1950s, the pioneers of the radiation chemistry of polymers began some experiments with radiation crosslinking of hydrophilic polymers. However, hydrogels were analyzed mainly from the point of view of the phenomenon associated with radiation synthesis, with topology of network and relation between radiation parameters of the processes. Fundamental monographs on radiation polymer physics and chemistry written by A. Charlesby (Atomic Radition and polymers, Pergamon Press, Oxford, 1960) and A. Chapiro (Radiation Chemistry of Polymeric Systems, Interscience, New York, 1962) proceed from this time. The noticeable interest in the application of radiation techniques to obtain hydrogels for biomedical purposes began in the late sixties as a result of the papers and patents invented by Japanese and American scientists, headed by Kaetsu in Japan and Hoffman in USA. Immobilization of biologically active species in hydrogel matrices, their use as drug delivery systems and enzyme traps as well as the modification of material surfaces to improve biocompatibility and their ability to bond antigens and antibodies had been the main subjects of these investigations. In this article a brief summary of investigations on mechanism and kinetics of radiation formation of hydrogels as well as some examples of commercialized hydrogel biomaterials have been

  1. Effects of Transplanted Heparin-Poloxamer Hydrogel Combining Dental Pulp Stem Cells and bFGF on Spinal Cord Injury Repair

    Directory of Open Access Journals (Sweden)

    Lihua Luo

    2018-01-01

    Full Text Available Spinal cord injury (SCI is one of serious traumatic diseases of the central nervous system and has no effective treatment because of its complicated pathophysiology. Tissue engineering strategy which contains scaffolds, cells, and growth factors can provide a promising treatment for SCI. Hydrogel that has 3D network structure and biomimetic microenvironment can support cellular growth and embed biological macromolecules for sustaining release. Dental pulp stem cells (DPSCs, derived from cranial neural crest, possess mesenchymal stem cell (MSC characteristics and have an ability to provide neuroprotective and neurotrophic properties for SCI treatment. Basic fibroblast growth factor (bFGF is able to promote cell survival and proliferation and also has beneficial effect on neural regeneration and functional recovery after SCI. Herein, a thermosensitive heparin-poloxamer (HP hydrogel containing DPSCs and bFGF was prepared, and the effects of HP-bFGF-DPSCs on neuron restoration after SCI were evaluated by functional recovery tests, western blotting, magnetic resonance imaging (MRI, histology evaluation, and immunohistochemistry. The results suggested that transplanted HP hydrogel containing DPSCs and bFGF had a significant impact on spinal cord repair and regeneration and may provide a promising strategy for neuron repair, functional recovery, and tissue regeneration after SCI.

  2. Increasing dwell time of mitomycin C in the upper tract with a reverse thermosensitive polymer.

    Science.gov (United States)

    Wang, Agnes J; Goldsmith, Zachariah G; Neisius, Andreas; Astroza, Gaston M; Oredein-McCoy, Olugbemisola; Iqbal, Muhammad W; Simmons, W Neal; Madden, John F; Preminger, Glenn M; Inman, Brant A; Lipkin, Michael E; Ferrandino, Michael N

    2013-03-01

    Abstract Background and Purpose: Topical chemotherapy for urothelial cancer is dependent on adequate contact time of the chemotherapeutic agent with the urothelium. To date, there has not been a reliable method of maintaining this contact for renal or ureteral urothelial carcinoma. We evaluated the safety and feasibility of using a reverse thermosensitive polymer to improve dwell times of mitomycin C (MMC) in the upper tract. Using a porcine model, four animals were treated ureteroscopically with both upper urinary tracts receiving MMC mixed with iodinated contrast. One additional animal received MMC percutaneously. The treatment side had ureteral outflow blocked with a reverse thermosensitive polymer plug. MMC dwell time was monitored fluoroscopically and intrarenal pressures measured. Two animals were euthanized immediately, and three animals were euthanized 5 days afterward. In control kidneys, drainage occurred at a mean of 5.3±0.58 minutes. Intrarenal pressures stayed fairly stable: 9.7±14.0 cm H20. In treatment kidneys, dwell time was extended to 60 minutes, when the polymer was washed out. Intrarenal pressures in the treatment kidneys peaked at 75.0±14.7 cm H20 and reached steady state at 60 cm H20. Pressures normalized after washout of the polymer with cool saline. Average washout time was 11.8±9.6 minutes. No histopathologic differences were seen between the control and treatment kidneys, or with immediate compared with delayed euthanasia. A reverse thermosensitive polymer can retain MMC in the upper urinary tract and appears to be safe from our examination of intrarenal pressures and histopathology. This technique may improve the efficacy of topical chemotherapy in the management of upper tract urothelial carcinoma.

  3. Thermo-sensitive nanoparticles for triggered release of siRNA.

    Science.gov (United States)

    Yang, Zheng; Cheng, Qiang; Jiang, Qian; Deng, Liandong; Liang, Zicai; Dong, Anjie

    2015-01-01

    Efficient delivery of small interfering RNA (siRNA) is crucially required for cancer gene therapy. Herein, a thermo-sensitive copolymer with a simple structure, poly (ethylene glycol) methyl ether acrylate-b-poly (N-isopropylacrylamide) (mPEG-b-PNIPAM) was developed. A novel kind of thermo-sensitive nanoparticles (DENPs) was constructed for the cold-shock triggered release of siRNA by double emulsion-solvent evaporation method using mPEG-b-PNIPAM and a cationic lipid, 3β [N-(N', N'-dimethylaminoethane)-carbamoyl] cholesterol [DC-Chol]. DENPs were observed by transmission electron microscopy and dynamical light scattering before and after 'cold shock' treatment. The encapsulation efficiency (EE) of siRNA in DENPs, which was measured by fluorescence spectrophotometer was 96.8% while it was significantly reduced to be 23.2% when DC-Chol was absent. DENPs/siRNA NPs exhibited a thermo-sensitive siRNA release character that the cumulatively released amount of siRNA from cold shock was approximately 2.2 folds higher after 7 days. In vitro luciferase silencing experiments indicated that DENPs showed potent gene silencing efficacy in HeLa-Luc cells (HeLa cells steadily expressed luciferase), which was further enhanced by a cold shock. Furthermore, MTT assay showed that cell viability with DENPs/siRNA up to 200 nM remained above 80%. We also observed that most of siRNA was accumulated in kidney mediated by DENPs instead of liver and spleen in vivo experiments. Thus, DENPs as a cold shock responsive quick release model for siRNA or hydrophilic macromolecules delivery provide a new way to nanocarrier design and clinic therapy.

  4. Microfluidics-assisted generation of stimuli-responsive hydrogels based on alginates incorporated with thermo-responsive and amphiphilic polymers as novel biomaterials.

    Science.gov (United States)

    Karakasyan, C; Mathos, J; Lack, S; Davy, J; Marquis, M; Renard, D

    2015-11-01

    We used a droplet-based microfluidics technique to produce monodisperse responsive alginate-block-polyetheramine copolymer microgels. The polyetheramine group (PEA), corresponding to a propylene oxide /ethylene oxide ratio (PO/EO) of 29/6 (Jeffamine(®) M2005), was condensed, via the amine link, to alginates with various mannuronic/guluronic acids ratios and using two alginate:jeffamine mass ratios. The size of the grafted-alginate microgels varied from 60 to 80 μm depending on the type of alginate used and the degree of substitution. The droplet-based microfluidics technique offered exquisite control of both the dimension and physical chemical properties of the grafted-alginate microgels. These microgels were therefore comparable to isolated grafted-alginate chains in retaining both their amphiphilic and thermo-sensitive properties. Amphiphilicity was demonstrated at the oil-water interface where grafted-alginate microgels were found to decrease interfacial tension by ∼ 50%. The thermo-sensitivity of microgels was clearly demonstrated and a 10 to 20% reduction in size between was evidenced on increasing the temperature above the lower critical solution temperature (TLCST) of Jeffamine. In addition, the reversibility of thermo-sensitivity was demonstrated by studying the oil-water affinity of microgels with temperature after Congo red labeling. Finally, droplet-based microfluidics was found to be a good and promising tool for generating responsive biobased hydrogels for drug delivery applications and potential new colloidal stabilizers for dispersed systems such as Pickering emulsions. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Synthesis of Highly Effective Novel Graphene Oxide-Polyethylene Glycol-Polyvinyl Alcohol Nanocomposite Hydrogel For Copper Removal

    Directory of Open Access Journals (Sweden)

    Eman Serag

    2017-10-01

    Full Text Available A novel Graphene oxide-polyethylene glycol and polyvinyl alcohol (GO-PEG-PVA triple network hydrogel were prepared to remove Copper(II ion from its aqueous solution. The structures, morphologies, and properties of graphene oxide (GO, the composite GO-PEG-PVA and PEG-PVA were characterized using FTIR, X-ray diffraction, Scanning Electronic Microscope and Thermal Gravimetric analysis. A series of systematic batch adsorption experiments were conducted to study the adsorption property of GO, GO-PEG-PVA hydrogel and PEG-PVA hydrogel under different conditions (e.g. pH, contact time and Cu2+ ions concentration. The high adsorption capacity, easy regeneration, and effective adsorption–desorption results proved that the prepared GO-PEG-PVA composite hydrogel could be an effective adsorbent in removing Cu2+ ion from its aqueous solution. The maximum adsorption capacities were found to be 917, 900 and 423 mg g–1 for GO-PEG-PVA hydrogel, GO and PEG-PVA hydrogel, respectively at pH 5, 25 °C and Cu2+ ions’ concentration 500 mg l–1. The removal efficiency of the recycled GO-PEG-PVA hydrogel were 83, 81, 80 and 79% for the first four times, which proved efficient reusability.

  6. Experimental evidence of temperature gradients in cavitating microflows seeded with thermosensitive nanoprobes

    Science.gov (United States)

    Ayela, Frédéric; Medrano-Muñoz, Manuel; Amans, David; Dujardin, Christophe; Brichart, Thomas; Martini, Matteo; Tillement, Olivier; Ledoux, Gilles

    2013-10-01

    Thermosensitive fluorescent nanoparticles seeded in deionized water combined with confocal microscopy enables thermal mapping over three dimensions of the liquid phase flowing through a microchannel interrupted by a microdiaphragm. This experiment reveals the presence of a strong thermal gradient up to ˜105 K/m only when hydrodynamic cavitation is present. Here hydrodynamic cavitation is the consequence of high shear rates downstream in the diaphragm. This temperature gradient is located in vortical structures associated with eddies in the shear layers. We attribute such overheating to the dissipation involved by the cavitating flow regime. Accordingly, we demonstrate that the microsizes of the device enhance the intensity of the thermal gap.

  7. Ionizing radiation in the field of hydrogels used for agriculture and medicine

    International Nuclear Information System (INIS)

    Radoiu, M.; Martin, D.; Oproiu, C.; Indreias, I; Toma, M.; Dragusin, M.; Moraru, R.; Manea, A.

    1998-01-01

    The hydrogels, such as homopolymers of acrylamide (AHH type), co-polymers of acrylamide-sodium acrylate (ANACH type) and homopolymers of sodium acrylate (NAHH type), obtained by gamma ray and accelerated electron beam are presented. The effects of the solution chemical composition, swelling medium nature, radiation absorbed dose and radiation absorbed dose rate upon the swelling degree and mechanical strength of these hydrogel types are discussed. Distilled water, physiological serum and 4 N NaCl aqueous solution were used as swelling medium. Radiation absorbed dose has an important effect upon the swelling degree of AHH and ANACH types especially when distilled water is used as swelling medium while the NAHH swelling degree presents a small dependence versus absorbed dose for all swelling medium types. Usually, the swelling degree for all hydrogel types decreases versus absorbed dose and absorbed dose rate and exhibits the higher values for distilled water as swelling medium. The hydrogels mechanical strength exhibits a maximum value versus absorbed dose. The best values for mechanical strength depend on hydrogel type and swelling medium. The used range for absorbed dose was from 2 kGy to 16 kGy. Our types of hydrogels were developed for some applications such as in agriculture (AHH and ANACH types) to maintain soil humidity and in medicine as absorption material for dressing (NAHH types). (author)

  8. Fast-responsive hydrogel as an injectable pump for rapid on-demand fluidic flow control.

    Science.gov (United States)

    Luo, Rongcong; Dinh, Ngoc-Duy; Chen, Chia-Hung

    2017-05-01

    Chemically synthesized functional hydrogels have been recognized as optimized soft pumps for on-demand fluidic regulation in micro-systems. However, the challenges regarding the slow responses of hydrogels have very much limited their application in effective fluidic flow control. In this study, a heterobifunctional crosslinker (4-hydroxybutyl acrylate)-enabled two-step hydrothermal phase separation process for preparing a highly porous hydrogel with fast response dynamics was investigated for the fabrication of novel microfluidic functional units, such as injectable valves and pumps. The cylinder-shaped hydrogel, with a diameter of 9 cm and a height of 2.5 cm at 25 °C, achieved a size reduction of approximately 70% in less than 30 s after the hydrogels were heated at 40 °C. By incorporating polypyrrole nanoparticles as photothermal transducers, a photo-responsive composite hydrogel was approached and exhibited a remotely triggerable fluidic regulation and pumping ability to generate significant flows, showing on-demand water-in-oil droplet generation by laser switching, whereby the droplet size could be tuned by adjusting the laser intensity and irradiation period with programmable manipulation.

  9. Microfluidic-Based Synthesis of Hydrogel Particles for Cell Microencapsulation and Cell-Based Drug Delivery

    Directory of Open Access Journals (Sweden)

    Jiandi Wan

    2012-04-01

    Full Text Available Encapsulation of cells in hydrogel particles has been demonstrated as an effective approach to deliver therapeutic agents. The properties of hydrogel particles, such as the chemical composition, size, porosity, and number of cells per particle, affect cellular functions and consequently play important roles for the cell-based drug delivery. Microfluidics has shown unparalleled advantages for the synthesis of polymer particles and been utilized to produce hydrogel particles with a well-defined size, shape and morphology. Most importantly, during the encapsulation process, microfluidics can control the number of cells per particle and the overall encapsulation efficiency. Therefore, microfluidics is becoming the powerful approach for cell microencapsulation and construction of cell-based drug delivery systems. In this article, I summarize and discuss microfluidic approaches that have been developed recently for the synthesis of hydrogel particles and encapsulation of cells. I will start by classifying different types of hydrogel material, including natural biopolymers and synthetic polymers that are used for cell encapsulation, and then focus on the current status and challenges of microfluidic-based approaches. Finally, applications of cell-containing hydrogel particles for cell-based drug delivery, particularly for cancer therapy, are discussed.

  10. Fabrication of keratin-silica hydrogel for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Kakkar, Prachi; Madhan, Balaraman, E-mail: bmadhan76@yahoo.co.in

    2016-09-01

    In the recent past, keratin has been fabricated into different forms of biomaterials like scaffold, gel, sponge, film etc. In lieu of the myriad advantages of the hydrogels for biomedical applications, a keratin-silica hydrogel was fabricated using tetraethyl orthosilicate (TEOS). Textural analysis shed light on the physical properties of the fabricated hydrogel, inturn enabling the optimization of the hydrogel. The optimized keratin-silica hydrogel was found to exhibit instant springiness, optimum hardness, with ease of spreadability. Moreover, the hydrogel showed excellent swelling with highly porous microarchitecture. MTT assay and DAPI staining revealed that keratin-silica hydrogel was biocompatible with fibroblast cells. Collectively, these properties make the fabricated keratin-silica hydrogel, a suitable dressing material for biomedical applications. - Highlights: • Keratin-silica hydrogel has been fabricated using sol–gel technique. • The hydrogel shows appropriate textural properties. • The hydrogel promotes fibroblast cells proliferation. • The hydrogel has potential soft tissue engineering applications like wound healing.

  11. Preparation of poly(polyethylene glycol methacrylate-co-acrylic acid) hydrogels by radiation and their physical properties

    International Nuclear Information System (INIS)

    Park, S.-E.; Nho, Y.-C.; Kim, H.-I.

    2004-01-01

    The pH-responsive copolymer hydrogels were prepared with the monomers of polyethylene glycol methacrylate and acrylic acid based on γ-ray irradiation technique. The gel content of these copolymer hydrogels varied depending on both the composition of monomers and the radiation dose. Maximum gel percent and degree of crosslinking were obtained at the composition of equal amount of comonomers. These copolymer hydrogels did not show any noticeable change in swelling at lower pH range. However they showed an abrupt increase in swelling at higher pH range due to the ionization of carboxyl groups. This pH-responsive swelling behavior was applied for the insulin carrier via oral delivery. Insulin-loaded copolymer hydrogels released most of their insulin in the simulated intestinal fluid which had a pH of 6.8 but not in the simulated gastric fluid which had a pH of 1.2

  12. Radiation Synthesis and Characterization of Polyvinyl alcohol/Acrylic acid Hydrogel and its Amoxicillin drug Delivery application

    International Nuclear Information System (INIS)

    El kelesh, N.A.; Ismail, S.A.; Abd El Wahab, S.Y.

    2012-01-01

    Polyvinyl alcohol /Acrylic acid based hydrogels can be synthesized by Gamma radiation technique using 60 Co irradiation cell at irradiation dose rate 1.8 Gray/second. The optimum conditions of hydrogel preparation takes place at different factors such as composition ratios of PVA/AAc, different comonomer concentration and different irradiation doses resulting in hydrogel with maximum gel percent as it obtained 98%. The structures of hydrogels were characterized by FTIR analysis. The results can be confirmed the expected structures as well as free radical copolymerization. According to the swelling studies, hydrogels with high content of AAc gave relatively high swelling percent. The hydrogel showed a super adsorbent with swelling capacity 10320 %. Water diffusion into such prepared hydrogel showed a non-Fickian type where a Fickian number was 0.77. This hydrogel was used for the adsorption of amoxicillin drug from their aqueous solutions. The factors affected on the uptake conditions such as ph, time and initial feed concentration on the amoxicillin adsorption capacity of hydrogel was studied depending on Freundlish model of adsorption isotherm.. It was observed that the interaction between drug and ionic comonomers was enhanced in alkaline medium and high initial feed concentration of the drug. The ability of the hydrogel and the affinity of the drug to be adsorbed can be cleared by determining the empirical constants n and k respectively from the logarithmic form of Freundlish equation. The recovery of drug was also investigated in different ph values to study the suitable condition of drug release as drug delivery system.

  13. Radiation synthesis of super absorbent PAAm/PAAc-Na hydrogels to enhance sandy soil water retention

    International Nuclear Information System (INIS)

    Abd El-Mohdy, H.L.; Hegazy, E.A.; Farag, S.A.; Abd El-Rasoul, Sh.M.; Ragab, A.M.; Tantawy, E.A.

    2009-01-01

    Preparation of super absorbent hydrogels obtained by radiation induced cross linking of polyacrylamide (PAAm) and poly sodium acrylate (PAAc-Na) was investigated for possible uses in agricultural fields . The swelling of the investigated hydrogels was mainly related to the type of their hydrophilic functional groups and/or the presence of polarized charges. The preparation conditions, such as irradiation dose and hydrogel blend compositions that influence the swelling of PAAm/PAAc-Na copolymers and alter their gel content and cross linking density were investigated. The higher the irradiation dose, the higher the gel content, and the lower the swelling ratio. The effect of some external parameters such as nutrient concentration, ph, and temperature on the swelling behaviour of prepared hydrogels was studied. studies were also made on the applications of such hydrogels to improve the physical and water retention properties of sandy soil for agricultural purposes. The experiments' design was complete randomized block with different doses of hydrogel as 5,10,15,20 and 25 kg/feddan (fed). Hydrogel granules added with peanut seeds during sowing , these plots received irrigation by sprinkle system two times daily during 6 days per week even near harvesting . Whereas control plants were irrigate two times daily during 7 days of the week. The parameters of productivity as morphological characters, NPK uptake and microbiological data were obtained during growth and harvesting . The effect of hydrogel doses on total bacterial counts (TBC) and nitrogen fixing bacteria (NFB) in the rhizosphere plant was studied after 45 days and at harvest

  14. Bioresorption mechanisms of chitosan physical hydrogels: A scanning electron microscopy study

    International Nuclear Information System (INIS)

    Malaise, Sébastien; Rami, Lila; Montembault, Alexandra; Alcouffe, Pierre; Burdin, Béatrice; Bordenave, Laurence; Delmond, Samantha; David, Laurent

    2014-01-01

    Tissue-engineered biodegradable medical devices are widely studied and systems must present suitable balance between versatility and elaboration simplicity. In this work, we aim at illustrating that such equilibrium can be found by processing chitosan physical hydrogels without external cross-linker. Chitosan concentration, degree of acetylation, solvent composition, and neutralization route were modulated in order to obtain hydrogels exhibiting different physico-chemical properties. The resulting in vivo biological response was investigated by scanning electron microscopy. “Soft” hydrogels were obtained from chitosan of high degree of acetylation (35%) and by the neutralization with gaseous ammonia of a chitosan acetate aqueous solutions presenting low polymer concentration (Cp = 1.6% w/w). “Harder” hydrogels were obtained from chitosan with lower degree of acetylation (5%) and after neutralization in sodium hydroxide bath (1 M) of hydro-alcoholic chitosan solutions (50/50 w/w water/1,2-propanediol) with a polymer concentration of 2.5% w/w. Soft and hard hydrogels exhibited bioresorption times from below 10 days to higher than 60 days, respectively. We also evidenced that cell colonization and neo-vascularization mechanisms depend on the hydrogel-aggregated structure that is controlled by elaboration conditions and possibly in relation with mechanical properties. Specific processing conditions induced micron-range capillary formation, which can be assimilated to colonization channels, also acting on the resorption scenario. - Highlights: • We elaborated physical chitosan hydrogels presenting tuneable biological properties. • Cell colonization mechanism depends on biological and mechanical hydrogel properties. • Increasing the degree of acetylation will reduce the bioresorption time. • Capillaries played a role of cell colonization pathways

  15. Bioresorption mechanisms of chitosan physical hydrogels: A scanning electron microscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Malaise, Sébastien, E-mail: sebastien.malaise@gmail.com [Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Ingénierie des Matériaux Polymères (IMP-UMR 5223), 15 Boulevard Latarjet, 69622 Villeurbanne Cedex (France); Rami, Lila [Université de Bordeaux, Bordeaux 33000 (France); Inserm U1026, Bioingénierie Tissulaire, Bordeaux 33000 (France); Montembault, Alexandra; Alcouffe, Pierre [Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Ingénierie des Matériaux Polymères (IMP-UMR 5223), 15 Boulevard Latarjet, 69622 Villeurbanne Cedex (France); Burdin, Béatrice [Université de Lyon, Université Claude Bernard Lyon 1, Centre Technologique des Microstructure, 69622 Villeurbanne Cedex (France); Bordenave, Laurence [Université de Bordeaux, Bordeaux 33000 (France); Inserm U1026, Bioingénierie Tissulaire, Bordeaux 33000 (France); CHU de Bordeaux, CIC-IT Biomaterials, F-33000 Bordeaux (France); Delmond, Samantha [CHU de Bordeaux, CIC-IT Biomaterials, F-33000 Bordeaux (France); David, Laurent [Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Ingénierie des Matériaux Polymères (IMP-UMR 5223), 15 Boulevard Latarjet, 69622 Villeurbanne Cedex (France)

    2014-09-01

    Tissue-engineered biodegradable medical devices are widely studied and systems must present suitable balance between versatility and elaboration simplicity. In this work, we aim at illustrating that such equilibrium can be found by processing chitosan physical hydrogels without external cross-linker. Chitosan concentration, degree of acetylation, solvent composition, and neutralization route were modulated in order to obtain hydrogels exhibiting different physico-chemical properties. The resulting in vivo biological response was investigated by scanning electron microscopy. “Soft” hydrogels were obtained from chitosan of high degree of acetylation (35%) and by the neutralization with gaseous ammonia of a chitosan acetate aqueous solutions presenting low polymer concentration (Cp = 1.6% w/w). “Harder” hydrogels were obtained from chitosan with lower degree of acetylation (5%) and after neutralization in sodium hydroxide bath (1 M) of hydro-alcoholic chitosan solutions (50/50 w/w water/1,2-propanediol) with a polymer concentration of 2.5% w/w. Soft and hard hydrogels exhibited bioresorption times from below 10 days to higher than 60 days, respectively. We also evidenced that cell colonization and neo-vascularization mechanisms depend on the hydrogel-aggregated structure that is controlled by elaboration conditions and possibly in relation with mechanical properties. Specific processing conditions induced micron-range capillary formation, which can be assimilated to colonization channels, also acting on the resorption scenario. - Highlights: • We elaborated physical chitosan hydrogels presenting tuneable biological properties. • Cell colonization mechanism depends on biological and mechanical hydrogel properties. • Increasing the degree of acetylation will reduce the bioresorption time. • Capillaries played a role of cell colonization pathways.

  16. Preparation of Zeolite Molecular Sieve by Using Hydrogel Method

    International Nuclear Information System (INIS)

    Swe Zin Win; Mu Mu Htay; Mya Mya Oo

    2010-12-01

    Zeolite A was synthesized from hydrogel solution which prepared from silica and alumina precursors under hydrothermal condition at atmospheric pressure. Before preparing of hydrogel solution, the amount of raw materials which used in resulting hydrogel with appropriate mole ratio was calculated by material balance. In this study,totally ten experiments were carried out for zeolite A formation. The important parameters for these experiments were the kinds of precursors,their concentration (starting material composition), synthesis time and temperature. All product samples from these experiments were characterized by X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and analyzed by gravimetric method. The results show that the favourable sample for this research work which can be prepared with a molar composition of SiO2: Al2O3: 2Na2O: 70H2O by agitation at room temperature for 30 minutes, ageing at room temperature and crystallization at 95Ccentre dot centre dot for 24hrs. The percent yield of favourable result is 70%.

  17. Polyvinyl alcohol hydrogels for iontohporesis

    Science.gov (United States)

    Bera, Prasanta; Alam, Asif Ali; Arora, Neha; Tibarewala, Dewaki Nandan; Basak, Piyali

    2013-06-01

    Transdermal therapeutic systems propound controlled release of active ingredients through the skin into the systemic circulation in a predictive manner. Drugs administered through these systems escape first-pass metabolism and maintain a steady state scenario similar to a continuous intravenous infusion for up to several days. The iontophoresis deal with the systemic delivery of the bioactive agents (drug) by applying an electric current. It is basically an injection without the needle. The iontophoretic system requires a gel-based matrix to accommodate the bioactive agent. Hydrogels have been used by many investigators in controlled-release drug delivery systems because of their good tissue compatibility and easy manipulation of swelling level and, thereby, solute permeability. In this work we have prepared polyvinyl alcohol (PVA) hydrogel. We have cross linked polyvinyl alcohol chemically with Glutaraldehyde with different wt%. FTIR study reveals the chemical changes during cross linking. Swelling in water, is done to have an idea about drug loading and drug release from the membrane. After drug loading to the hydrogels, we have studied the drug release property of the hydrogels using salicylic acid as a model drug.

  18. 3D printable conducting hydrogels containing chemically converted graphene.

    Science.gov (United States)

    Sayyar, Sepidar; Gambhir, Sanjeev; Chung, Johnson; Officer, David L; Wallace, Gordon G

    2017-02-02

    The development of conducting 3D structured biocompatible scaffolds for the growth of electroresponsive cells is critical in the field of tissue engineering. This work reports the synthesis and 3D processing of UV-crosslinkable conducting cytocompatible hydrogels that are prepared from methacrylated chitosan (ChiMA) containing graphenic nanosheets. The addition of chemically converted graphene resulted in mechanical and electrical properties of the composite that were significantly better than ChiMA itself, as well as improved adhesion, proliferation and spreading of L929 fibroblasts cells. The chemically converted graphene/ChiMA hydrogels were amenable to 3D printing and this was used to produce multilayer scaffolds with enhanced mechanical properties through UV-crosslinking.

  19. Investigation on Au-nano incorporated pH-sensitive (itaconic acid/acrylic acid/triethylene glycol) based polymeric biocompatible hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Sakthivel, M., E-mail: msakthi81986@gmail.com [Research and Development Centre, Bharathiar University, Coimbatore 641 046, Tamilnadu (India); Department of Chemistry, Ganadipathy Tulsi' s Jain Engineering College, Kaniyambadi, Vellore 632 102, Tamilnadu (India); Franklin, D.S., E-mail: loyolafrank@yahoo.co.in [Department of Chemistry, C. Abdul Hakeem College of Engineering and Technology, Melvisharam 632509, Tamilnadu (India); Sudarsan, S., E-mail: srsudarsan29@gmail.com [Department of Chemistry, Periyar University, Salem 636011, Tamilnadu (India); Chitra, G., E-mail: chitramuralikrishnan@gmail.com [Department of Chemistry, Periyar University, Salem 636011, Tamilnadu (India); Guhanathan, S., E-mail: sai_gugan@yahoo.com [PG & Research Department of Chemistry, Muthurangam Government Arts College, Vellore 632 002, Tamilnadu (India)

    2017-06-01

    The pH-sensitive gold nano hydrogel based on itaconic acid, acrylic acid and triethylene glycol (GIAT) has been prepared by free radical polymerization viz. organic solventless approach with different monomer ratios. The nature of bonding and structural identification of GIAT hydrogels were characterized by FT-IR spectroscopy. The surface morphology of gold gel was examined using scanning electron microscopy (SEM). In addition, transmission electron microscopy (TEM) was used to identify the size of gold nano particles. The in vitro biocompatibility of GIAT hydrogel has been evaluated in 3T3 fibroblast cell lines. The obtained results show that gold nano particle incorporated hydrogel possess ~ 99% of cell proliferation. Followed by, the impact of gold nano particles on swelling, surface morphology was studied. The consecutive preparation of hydrogel, effect of different pH conditions, and stoichiometry of monomeric units have also been discussed. The degree of swelling was measured in carbonate buffer solutions for 24 h period with varying pH such as 1.2, 6.0, 7.4 and 10.0. The obtained results showed that the stoichiometry of itaconic acid and gold nano particles plays an essential role in modifying the nature of GIAT polymeric hydrogels. In conclusion, promising Au-nano incorporated pH-sensitive bio polymeric hydrogels were prepared and characterized. The unique properties of these Au-nano hydrogel make them attractive use in biomedical applications. - Highlights: • Itaconic acid based hydrogels were developed viz. greener organic solvent less approach. • The enhanced equilibrium swelling at acidic and basic medium was observed for nano-Au-incorporated nano composite hydrogels. • The prepared GIAT hydrogel showed ~ 99% of cell proliferation. • This kind of pH-sensitive polymeric hydrogels may be useful for controlled drug delivery system.

  20. Poly(ethylene glycol) dicarboxylate/poly(ethylene oxide) hydrogel film co-crosslinked by electron beam irradiation as an anti-adhesion barrier

    International Nuclear Information System (INIS)

    Haryanto,; Singh, Deepti; Han, Sung Soo; Son, Jun Hyuk; Kim, Seong Cheol

    2015-01-01

    The cross-linked poly(ethylene glycol) dicarboxylate (PEGDC)/poly(ethylene oxide) (PEO) and poly(ethylene glycol) dimethacrylate (PEGDMA)/(PEO) hydrogels were developed for possible biomedical applications such as an anti-adhesion barrier. Various contents of PEGDC/PEO film were irradiated using an electron beam with various beam intensities in order to obtain various degrees of crosslinked hydrogels. The optimum dose (300 kGy) and total crosslinker content of 10% were used to prepare crosslinked hydrogel films with three different compositions (10% PEGDC, 10% PEGDMA, 5% PEGDC–5% PEGDMA). Among them, 10% PEGDC hydrogel film exhibited the highest elongation at break (69.33 ± 6.87%) with high mechanical strength. 10% PEGDC hydrogel film showed the lowest hemolysis activity (6.03 ± 0.01%) and the highest tissue adherence (75.67 ± 1.15 cN). The result also indicated that the carboxyl groups in PEGDC affect the tissue adherence of hydrogel films via H-bonding interactions. In animal studies, 10% PEGDC anti-adhesion hydrogel film degraded within 3 weeks and demonstrated better anti-adhesive effect compared to Guardix-SG®. - Highlights: • The crosslinked PEGDC/PEO hydrogel was developed by e-beam irradiation. • 10% PEGDC hydrogel film showed the highest elongation at break and tissue adhesion. • The COOH group enhanced the tissue adherence of hydrogel films on the intestine. • 10% PEGDC hydrogel film demonstrated a good anti-adhesive effect in animal study. • All of the hydrogel films with 10% PEGDC degraded in vivo within three weeks

  1. Investigation on Au-nano incorporated pH-sensitive (itaconic acid/acrylic acid/triethylene glycol) based polymeric biocompatible hydrogels

    International Nuclear Information System (INIS)

    Sakthivel, M.; Franklin, D.S.; Sudarsan, S.; Chitra, G.; Guhanathan, S.

    2017-01-01

    The pH-sensitive gold nano hydrogel based on itaconic acid, acrylic acid and triethylene glycol (GIAT) has been prepared by free radical polymerization viz. organic solventless approach with different monomer ratios. The nature of bonding and structural identification of GIAT hydrogels were characterized by FT-IR spectroscopy. The surface morphology of gold gel was examined using scanning electron microscopy (SEM). In addition, transmission electron microscopy (TEM) was used to identify the size of gold nano particles. The in vitro biocompatibility of GIAT hydrogel has been evaluated in 3T3 fibroblast cell lines. The obtained results show that gold nano particle incorporated hydrogel possess ~ 99% of cell proliferation. Followed by, the impact of gold nano particles on swelling, surface morphology was studied. The consecutive preparation of hydrogel, effect of different pH conditions, and stoichiometry of monomeric units have also been discussed. The degree of swelling was measured in carbonate buffer solutions for 24 h period with varying pH such as 1.2, 6.0, 7.4 and 10.0. The obtained results showed that the stoichiometry of itaconic acid and gold nano particles plays an essential role in modifying the nature of GIAT polymeric hydrogels. In conclusion, promising Au-nano incorporated pH-sensitive bio polymeric hydrogels were prepared and characterized. The unique properties of these Au-nano hydrogel make them attractive use in biomedical applications. - Highlights: • Itaconic acid based hydrogels were developed viz. greener organic solvent less approach. • The enhanced equilibrium swelling at acidic and basic medium was observed for nano-Au-incorporated nano composite hydrogels. • The prepared GIAT hydrogel showed ~ 99% of cell proliferation. • This kind of pH-sensitive polymeric hydrogels may be useful for controlled drug delivery system.

  2. New cellulose–lignin hydrogels and their application in controlled release of polyphenols

    International Nuclear Information System (INIS)

    Ciolacu, Diana; Oprea, Ana Maria; Anghel, Narcis; Cazacu, Georgeta; Cazacu, Maria

    2012-01-01

    Novel superabsorbant cellulose–lignin hydrogels (CL) were prepared by a new two-step procedure consisting in dissolving cellulose in an alkaline solution with further mixing with lignin, followed by the chemical crosslinking with epichlorohydrin. The crosslinking occurrence was verified by Fourier Transform Infrared spectroscopy (FT-IR). The effect of the structure features of cellulose–lignin hydrogels on their dehydration heat was evaluated by Differential Scanning Calorimetry (DSC). The Scanning Electron Microscopy (SEM) images reveal some morphological aspects of the hydrogels. The degree as well as the rate of swelling in a mixture of water:ethanol = 19:1 were estimated. The possible application of these hydrogels as controlled release systems was tested. Polyphenols known as having a wide range of biological effects were selected to be incorporated in such hydrogels by an optimal procedure. The extract of grapes seeds from the Chambourcin type was used as a source of polyphenols (PF). The amount of the incorporated polyphenols was estimated by UV–VIS measurements. Characterization of the hydrogels containing polyphenols was performed by FTIR spectroscopy. Some parameters were estimated based on the registered spectra, as H-bond energy (E H ), the asymmetric index (a/b) and the enthalpy of H-bond formation (ΔH). The modifications of the thermal behavior and morphology induced by the presence of the polyphenols in hydrogels were highlighted by DSC and SEM, respectively. The release of polyphenols from CL hydrogels depended on the lignin content from matrices, as assessed by spectral studies. Both loading with polyphenols and their release can be controlled by the composition of the hydrogels. The kinetic of polyphenols release was studied. - Highlights: ► A unique method to obtain cellulose–lignin hydrogels. ► The application of these hydrogels as controlled release systems was tested. ► Polyphenols from grapes seed as active ingredient.

  3. Phase-Separated Polyaniline/Graphene Composite Electrodes for High-Rate Electrochemical Supercapacitors.

    Science.gov (United States)

    Wu, Jifeng; Zhang, Qin'e; Zhou, An'an; Huang, Zhifeng; Bai, Hua; Li, Lei

    2016-12-01

    Polyaniline/graphene hydrogel composites with a macroscopically phase-separated structure are prepared. The composites show high specific capacitance and excellent rate performance. Further investigation demonstrates that polyaniline inside the graphene hydrogel has low rate performance, thus a phase-separated structure, in which polyaniline is mainly outside the graphene hydrogel matrix, can enhance the rate performance of the composites. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Enhancing Antidepressant Effect of Poloxamer/Chitosan Thermosensitive Gel Containing Curcumin-Cyclodextrin Inclusion Complex

    Directory of Open Access Journals (Sweden)

    Ye Zhang

    2018-01-01

    Full Text Available Poor solubility and bioavailability are limiting factors for the clinical application of curcumin. This study seeks to develop poloxamer/chitosan thermosensitive gel containing curcumin-cyclodextrin inclusion complex with enhanced brain bioavailability and antidepressant effect. The optimized gel had shorter gelation time and produced sustained release in vitro characterized with non-Fickian diffusion. Pharmacokinetics of gel were evaluated using male Sprague-Dawley rats receiving 240 μg/kg of curcumin and curcumin-cyclodextrin inclusion complex through intranasal administration, compared against a control group receiving intravenous curcumin (240 μg/kg. The intranasal administration of gel provided sustained release by maintaining plasma concentrations of curcumin above 21.27 ± 3.26 ng/mL for up to 8 h. Compared to intranasal administration of the inclusion complex, AUC0–8 h of curcumin from thermoreversible gel in plasma and hippocampus was increased 1.62- and 1.28-fold, respectively. The gel exhibited superior antidepressant activity in mice. The findings reported here suggested that the clinical application of curcumin can be better exploited through an intranasal administration of the thermosensitive gel.

  5. Investigation of a new thermosensitive block copolymer micelle: hydrolysis, disruption, and release.

    Science.gov (United States)

    Pelletier, Maxime; Babin, Jérôme; Tremblay, Luc; Zhao, Yue

    2008-11-04

    Thermosensitive polymer micelles are generally obtained with block copolymers in which one block exhibits a lower critical solution temperature in aqueous solution. We investigate a different design that is based on the use of one block bearing a thermally labile side group, whose hydrolysis upon heating shifts the hydrophilic-hydrophobic balance toward the destabilization of block copolymer micelles. Atom transfer radical polymerization was utilized to synthesize a series of diblock copolymers composed of hydrophilic poly(ethylene oxide) (PEO) and hydrophobic poly(2-tetrahydropyranyl methacrylate) (PTHPMA). We show that micelles of PEO-b-PTHPMA in aqueous solution can be destabilized as a result of the thermosensitive hydrolytic cleavage of tetrahydropyranyl (THP) groups that transforms PTHPMA into hydrophilic poly(methacrylic acid). The three related processes occurring in aqueous solution, namely, hydrolytic cleavage of THP, destabilization of micelles, and release of loaded Nile Red (NR), were investigated simultaneously using 1H NMR, dynamic light scattering, and fluorescence spectroscopy, respectively. At 80 degrees C, the results suggest that the three events proceed with a similar kinetics. Although slower than at elevated temperatures, the disruption of PEO-b-PTHPMA micelles can take place at the body temperature (approximately 37 degrees C), and the release kinetics of NR can be adjusted by changing the relative lengths of the two blocks or the pH of the solution.

  6. Thermo-sensitive polymer nanospheres as a smart plugging agent for shale gas drilling operations.

    Science.gov (United States)

    Wang, Wei-Ji; Qiu, Zheng-Song; Zhong, Han-Yi; Huang, Wei-An; Dai, Wen-Hao

    2017-01-01

    Emulsifier-free poly(methyl methacrylate-styrene) [P(MMA-St)] nanospheres with an average particle size of 100 nm were synthesized in an isopropyl alcohol-water medium by a solvothermal method. Then, through radical graft copolymerization of thermo-sensitive monomer N -isopropylacrylamide (NIPAm) and hydrophilic monomer acrylic acid (AA) onto the surface of P(MMA-St) nanospheres at 80 °C, a series of thermo-sensitive polymer nanospheres, named SD-SEAL with different lower critical solution temperatures (LCST), were prepared by adjusting the mole ratio of NIPAm to AA. The products were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, particle size distribution, and specific surface area analysis. The temperature-sensitive behavior was studied by light transmittance tests, while the sealing performance was investigated by pressure transmission tests with Lungmachi Formation shales. The experimental results showed that the synthesized nanoparticles are sensitive to temperature and had apparent LCST values which increased with an increase in hydrophilic monomer AA. When the temperature was higher than its LCST value, SD-SEAL played a dual role of physical plugging and chemical inhibition, slowed down pressure transmission, and reduced shale permeability remarkably. The plugged layer of shale was changed to being hydrophobic, which greatly improved the shale stability.

  7. Thermotolerance and thermosensitization in CHO and R1H cells: a comparative study

    International Nuclear Information System (INIS)

    Dikomey, E.; Eickhoff, J.; Jung, H.

    1984-01-01

    In CHO and R1H cells thermotolerance was induced by a pre-incubation at 40 0 C, by an acute heat shock at 43 0 C followed by a time interval at 37 0 C, and during continuous heating at 42 0 C. Thermotolerance, which was tested at 43 0 , primarily causes an increase in D 0 of the heat-response curve. The degree of maximum thermotolerance was found to be generally more pronounced in CHO than in R1H cells, but the time interval at 37 0 C, as well as at 40 0 C, to reach this maximum level was the same in both cell lines. CHO and R1H cells could be sensitized to 40 0 C by a pre-treatment at 43 0 C. When compared for the same survival rate after pre-treatment at 43 0 C alone the degree of thermosensitization was about the same in both cell lines. In either cell line thermosensitization was found to be suppressed when cells were made thermotolerant by a previous incubation at 40 0 C for 16 hours. (author)

  8. Novel thermo-sensitive core-shell nanoparticles for targeted paclitaxel delivery

    International Nuclear Information System (INIS)

    Li Yuanpei; Pan Shirong; Zhang Wei; Du Zhuo

    2009-01-01

    Novel thermo-sensitive nanoparticles self-assembled from poly(N,N-diethylacrylamide- co-acrylamide)-block-poly(γ-benzyl L-glutamate) were designed for targeted drug delivery in localized hyperthermia. The lower critical solution temperature (LCST) of nanoparticles was adjusted to a level between physiological body temperature (37 deg. C) and that used in local hyperthermia (about 43 deg. C). The temperature-dependent performances of the core-shell nanoparticles were systemically studied by nuclear magnetic resonance (NMR), circular dichroism (CD), fluorescence spectroscopy, dynamic light scattering (DLS), and atom force microscopy (AFM). The mean diameter of the nanoparticles increased slightly from 110 to 129 nm when paclitaxel (PTX), a poorly water-soluble anti-tumor drug, was encapsulated. A stability study in bovine serum albumin (BSA) solution indicated that the PTX loaded nanoparticles may have a long circulation time under physiological environments as the LCST was above physiological body temperature and the shell remained hydrophilic at 37 deg.C. The PTX release profiles showed thermo-sensitive controlled behavior. The proliferation inhibiting activity of PTX loaded nanoparticles was evaluated against Hela cells in vitro, compared with Taxol (a formulation of paclitaxel dissolved in Cremophor EL and ethanol). The cytotoxicity of PTX loaded nanoparticles increased obviously when hyperthermia was performed. The nanoparticles synthesized here could be an ideal candidate for thermal triggered anti-tumor PTX delivery system.

  9. In situ delivery of thermosensitive gel-mediated 5-fluorouracil microemulsion for the treatment of colorectal cancer

    Science.gov (United States)

    Wang, Lu-Lu; Huang, Shuai; Guo, Hui-Hui; Han, Yan-Xing; Zheng, Wen-Sheng; Jiang, Jian-Dong

    2016-01-01

    In situ administration of 5-fluorouracil (5FU) “thermosensitive” gel effectively reduced systemic side effects in treating colon rectal cancer; however, the penetration efficacy of the formulation was considerably low due to the poor lipid solubility of 5FU. The aim of this study was to develop thermosensitive gel-mediated 5FU water-in-oil microemulsion (TG-5FU-ME) for improving the infiltration of 5FU. An in vitro release test showed that TG-5FU-ME sustained the drug’s release up to 10 hours. TG-5FU-ME exhibited good stability, and the microemulsion entrapped did not show any change in morphology and 5FU content during the 4-month storage. Transportation test in the Caco-2 cell monolayer showed that TG-5FU-ME had a permeability 6.3 times higher than that of 5FU thermosensitive gel, and the intracellular uptake of 5FU increased by 5.4-fold compared to that of 5FU thermosensitive gel. In vivo tissue distribution analysis exhibited that the TG-5FU-ME group had drug levels in rectal tissue and mesenteric lymph nodes, which were significantly higher than those of 5FU thermosensitive gel group, with very low blood levels of 5FU in both groups. Furthermore, TG-5FU-ME was not associated with detectable morphological damage to the rectal tissue. Conclusively, TG-5FU-ME might be an efficient rectal delivery system to treat colorectal cancer. PMID:27660416

  10. γ-Rays-induced synthesis of hydrogels of vinyl ethers with stimuli-sensitive behavior

    International Nuclear Information System (INIS)

    Nam, I.K.; Mun, G.A.; Urkimbaeva, P.I.; Nurkeeva, Z.S.

    2003-01-01

    γ-Radiation method was applied to synthesize novel water-soluble and water-swelling polymers. Vinyl ether of ethylene glycol (VEEG), vinyl butyl (VBE) and vinyl isobutyl (VIBE) ethers were used as monomers. The synthesis of VEEG-VBE and VEEG-VIBE copolymers was carried out in a wide range of feed composition and absorbed dose. It was found that the hydrophobic-hydrophilic balance of the copolymers could be delicately varied by the copolymer composition as well as by the chemical structure of the alkyl substitute in the hydrophobic moiety. The copolymers exhibit thermo-sensitive behavior in water solutions. The value of transition temperature is considerably decreased at a higher concentration of the hydrophobic component in the copolymer composition

  11. Effects of pore forming agents on chitosan-graft-poly(N-vinylpyrrolidone) hydrogel properties for use as a matrix for floating drug delivery

    Science.gov (United States)

    Budianto, E.; Al-Shidqi, M. F.; Cahyana, A. H.

    2017-07-01

    Eradicating H. pylori-based infection by using conventional oral dosage form of amoxicillin trihydrate finds difficulties to overcome rapid gastric retention time. Encapsulating amoxicillin trihydrate in floating drug delivery system may solve the problem. In this research, the floating drug delivery system of amoxicillin trihydrate encapsulated in floating chitosan-graft-poly(N-vinyl pyrrolidone) hydrogels containing CaCO3 and NaHCO3 as pore forming agents has been successfully prepared. Pore forming agents used was varied with the ratio of 10 to 25% pore forming agents to total mass of the used materials. The hydrogel were characterizedusing FTIR spectrophotometer and stereo microscope. As pore forming agents compositions increased, the porosity (%) and floating properties increased but followed by decrease in drug entrapment efficiency. Most of the floating hydrogels possessed floating ability longer than 180 min and the highest porosity was found in hydrogel containing 25% NaHCO3. Hydrogel containing CaCO3 showed sustained drug release profile than hydrogel containing NaHCO3. However, the optimum formulation was achieved at composition of 10% NaHCO3 with 57% of drug entrapped within the hydrogel and 43% drug released. The results of these studies show that NaHCO3 is an effective pore forming agents for chitosan-graft-poly(N-vinyl pyrrolidone) hydrogel preparation as compare to CaCO3.

  12. Radiologic Findings in Hydrated Hydrogel Buckles

    International Nuclear Information System (INIS)

    Lee, Sung Bok; Lee, Nam Ho; Jo, Young Joon; Kim, Jung Yeul; Lee, Yeon Hee; Kim, Song Soo

    2008-01-01

    Hydrogel buckles, which are used in scleral buckling surgery for retinal detachment, have been associated with late complications after successful retinal reattachment surgery, including strabismus, extraocular motility restriction, extrusion through the eyelid or conjunctiva, intraocular erosion, and scleral erosion. Hydrogel buckles sometimes appear as well-marginated, circumferential, lobulating, contoured cystic masses mimicking orbital cysts on orbital CT or MRI. We report the radiologic findings in 5 patients whose hydrogel buckles needed to be differentiated from orbital cysts

  13. Radiologic Findings in Hydrated Hydrogel Buckles

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sung Bok; Lee, Nam Ho; Jo, Young Joon; Kim, Jung Yeul; Lee, Yeon Hee; Kim, Song Soo [Chungnam National University, Daejeon (Korea, Republic of)

    2008-11-15

    Hydrogel buckles, which are used in scleral buckling surgery for retinal detachment, have been associated with late complications after successful retinal reattachment surgery, including strabismus, extraocular motility restriction, extrusion through the eyelid or conjunctiva, intraocular erosion, and scleral erosion. Hydrogel buckles sometimes appear as well-marginated, circumferential, lobulating, contoured cystic masses mimicking orbital cysts on orbital CT or MRI. We report the radiologic findings in 5 patients whose hydrogel buckles needed to be differentiated from orbital cysts.

  14. Microengineered 3D cell-laden thermoresponsive hydrogels for mimicking cell morphology and orientation in cartilage tissue engineering.

    Science.gov (United States)

    Mellati, Amir; Fan, Chia-Ming; Tamayol, Ali; Annabi, Nasim; Dai, Sheng; Bi, Jingxiu; Jin, Bo; Xian, Cory; Khademhosseini, Ali; Zhang, Hu

    2017-01-01

    Mimicking the zonal organization of native articular cartilage, which is essential for proper tissue functions, has remained a challenge. In this study, a thermoresponsive copolymer of chitosan-g-poly(N-isopropylacrylamide) (CS-g-PNIPAAm) was synthesized as a carrier of mesenchymal stem cells (MSCs) to provide a support for their proliferation and differentiation. Microengineered three-dimensional (3D) cell-laden CS-g-PNIPAAm hydrogels with different microstripe widths were fabricated to control cellular alignment and elongation in order to mimic the superficial zone of natural cartilage. Biochemical assays showed six- and sevenfold increment in secretion of glycosaminoglycans (GAGs) and total collagen from MSCs encapsulated within the synthesized hydrogel after 28 days incubation in chondrogenic medium. Chondrogenic differentiation was also verified qualitatively by histological and immunohistochemical assessments. It was found that 75 ± 6% of cells encapsulated within 50 μm wide microstripes were aligned with an aspect ratio of 2.07 ± 0.16 at day 5, which was more organized than those observed in unpatterned constructs (12 ± 7% alignment and a shape index of 1.20 ± 0.07). The microengineered constructs mimicked the cell shape and organization in the superficial zone of cartilage whiles the unpatterned one resembled the middle zone. Our results suggest that microfabrication of 3D cell-laden thermosensitive hydrogels is a promising platform for creating biomimetic structures leading to more successful multi-zonal cartilage tissue engineering. Biotechnol. Bioeng. 2017;114: 217-231. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  15. Microscale Bioadhesive Hydrogel Arrays for Cell Engineering Applications

    Science.gov (United States)

    PATEL, RAVI GHANSHYAM; PURWADA, ALBERTO; CERCHIETTI, LEANDRO; INGHIRAMI, GIORGIO; MELNICK, ARI; GAHARWAR, AKHILESH K.; SINGH, ANKUR

    2014-01-01

    Bioengineered hydrogels have been explored in cell and tissue engineering applications to support cell growth and modulate its behavior. A rationally designed scaffold should allow for encapsulated cells to survive, adhere, proliferate, remodel the niche, and can be used for controlled delivery of biomolecules. Here we report a microarray of composite bioadhesive microgels with modular dimensions, tunable mechanical properties and bulk modified adhesive biomolecule composition. Composite bioadhesive microgels of maleimide functionalized polyethylene glycol (PEG-MAL) with interpenetrating network (IPN) of gelatin ionically cross-linked with silicate nanoparticles were engineered by integrating microfabrication with Michael-type addition chemistry and ionic gelation. By encapsulating clinically relevant anchorage-dependent cervical cancer cells and suspension leukemia cells as cell culture models in these composite microgels, we demonstrate enhanced cell spreading, survival, and metabolic activity compared to control gels. The composite bioadhesive hydrogels represent a platform that could be used to study independent effect of stiffness and adhesive ligand density on cell survival and function. We envision that such microarrays of cell adhesive microenvironments, which do not require harsh chemical and UV crosslinking conditions, will provide a more efficacious cell culture platform that can be used to study cell behavior and survival, function as building blocks to fabricate 3D tissue structures, cell delivery systems, and high throughput drug screening devices. PMID:25328548

  16. Formulation of sage essential oil (Salvia officinalis, L.) monoterpenes into chitosan hydrogels and permeation study with GC-MS analysis.

    Science.gov (United States)

    Kodadová, Alexandra; Vitková, Zuzana; Herdová, Petra; Ťažký, Anton; Oremusová, Jarmila; Grančai, Daniel; Mikuš, Peter

    2015-01-01

    This study deals with the formulation of natural drugs into hydrogels. For the first time, compounds from the sage essential oil were formulated into chitosan hydrogels. A sample preparation procedure for hydrophobic volatile analytes present in a hydrophilic water matrix along with an analytical method based on the gas chromatography coupled with the mass spectrometry (GC-MS) was developed and applied for the evaluation of the identity and quantity of essential oil components in the hydrogels and saline samples. The experimental results revealed that the chitosan hydrogels are suitable for the formulation of sage essential oil. The monoterpene release can be effectively controlled by both chitosan and caffeine concentration in the hydrogels. Permeation experiment, based on a hydrogel with the optimized composition [3.5% (w/w) sage essential oil, 2.0% (w/w) caffeine, 2.5% (w/w) chitosan and 0.1% (w/w) Tween-80] in donor compartment, saline solution in acceptor compartment, and semi-permeable cellophane membrane, demonstrated the useful permeation selectivity. Here, (according to lipophilicity) an enhanced permeation of the bicyclic monoterpenes with antiflogistic and antiseptic properties (eucalyptol, camphor and borneol) and, at the same time, suppressed permeation of toxic thujone (not exceeding its permitted applicable concentration) was observed. These properties highlight the pharmaceutical importance of the developed chitosan hydrogel formulating sage essential oil in the dermal applications.

  17. Preparation of Polyvinyl Pyrrolidone-Based Hydrogels by Radiation Induced Crosslinking with Potential Application as Wound Dressing

    International Nuclear Information System (INIS)

    Abd EI-Mohdy, H.L.; Hegazy, E.A.

    2009-01-01

    Polyvinyl pyrrolidone l polyethylene glycol hydrogels (PVP/ PEG) and PVP/ PEG/ Starch were prepared by irradiating the mixtures of aqueous solutions of PVP, PEG and starch with electron beam at different doses. Its properties were evaluated to identify their usability in wound dressing applications. Hydrogel dressing can protect injured skin and keep it appropriately moist to speed the healing process. The physical properties of the prepared hydrogels, such as gel content, swelling, water content and degree of water evaporation with varying composition and irradiation dose were examined to evaluate the usefulness of the hydrogels for wound dressing. The gel content increases with increasing PVP concentration due to increased crosslink density, and decreases with increasing the PEG concentration. PEG seems to act not only as plasticizer but also to modify the gel properties as gelation% and maximum swelling. Mechanical experiments were conducted for both of PVP/PEG and PVP/PEG/ Starch. The adding of PEG and starch to PVP significantly improve elongation and tensile strength of prepared hydrogels. The crystallinity of prepared hydrogels was investigated with varying their components. XRD studies indicated that the crystallinity in the gel was mainly due to PVP and decreased with enhanced starch content. The prepared hydrogels had sufficient strength to be used as wound dressing and could be considered as a good barrier against microbes

  18. Cytocompatible in situ forming chitosan/hyaluronan hydrogels via a metal-free click chemistry for soft tissue engineering.

    Science.gov (United States)

    Fan, Ming; Ma, Ye; Mao, Jiahui; Zhang, Ziwei; Tan, Huaping

    2015-07-01

    Injectable hydrogels are important cell scaffolding materials for tissue engineering and regenerative medicine. Here, we report a new class of biocompatible and biodegradable polysaccharide hydrogels derived from chitosan and hyaluronan via a metal-free click chemistry, without the addition of copper catalyst. For the metal-free click reaction, chitosan and hyaluronan were modified with oxanorbornadiene (OB) and 11-azido-3,6,9-trioxaundecan-1-amine (AA), respectively. The gelation is attributed to the triazole ring formation between OB and azido groups of polysaccharide derivatives. The molecular structures were verified by FT-IR spectroscopy and elemental analysis, giving substitution degrees of 58% and 47% for chitosan-OB and hyaluronan-AA, respectively. The in vitro gelation, morphologies, equilibrium swelling, compressive modulus and degradation of the composite hydrogels were examined. The potential of the metal-free hydrogel as a cell scaffold was demonstrated by encapsulation of human adipose-derived stem cells (ASCs) within the gel matrix in vitro. Cell culture showed that this metal-free hydrogel could support survival and proliferation of ASCs. A preliminary in vivo study demonstrated the usefulness of the hydrogel as an injectable scaffold for adipose tissue engineering. These characteristics provide a potential opportunity to use the metal-free click chemistry in preparation of biocompatible hydrogels for soft tissue engineering applications. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  19. Magnetic Nanoparticles Coated with a Thermosensitive Polymer with Hyperthermia Properties

    Directory of Open Access Journals (Sweden)

    Felisa Reyes-Ortega

    2017-12-01

    Full Text Available Magnetic nanoparticles (MNPs have been widely used to increase the efficacy of chemotherapeutics, largely through passive accumulation provided by the enhanced permeability and retention effect. Their incorporation into biopolymer coatings enables the preparation of magnetic field-responsive, biocompatible nanoparticles that are well dispersed in aqueous media. Here we describe a synthetic route to prepare functionalized, stable magnetite nanoparticles (MNPs coated with a temperature-responsive polymer, by means of the hydrothermal method combined with an oil/water (o/w emulsion process. The effects of both pH and temperature on the electrophoretic mobility and surface charge of these MNPs are investigated. The magnetite/polymer composition of these systems is detected by Fourier Transform Infrared Spectroscopy (FTIR and quantified by thermogravimetric analysis. The therapeutic possibilities of the designed nanostructures as effective heating agents for magnetic hyperthermia are demonstrated, and specific absorption rates as high as 150 W/g, with 20 mT magnetic field and 205 kHz frequency, are obtained. This magnetic heating response could provide a promising nanoparticle system for combined diagnostics and cancer therapy.

  20. Solutions for care of silicone hydrogel lenses.

    Science.gov (United States)

    Willcox, Mark D P

    2013-01-01

    During wear of contact lenses on a daily wear basis, it is necessary to disinfect the lens overnight before reinserting the lens the next day. The ability of the solutions used for this to disinfect lenses and lens cases is important for safe lens wear. The literature on the disinfecting ability of multipurpose disinfecting solutions (MPDS) commonly used with silicone hydrogel lenses reported during the period 2000 to 2012 is reviewed, as this is the period of time during which these lenses have been commercially available. Particular emphasis is placed on the ability of disinfecting solutions to control colonization of lens cases by microbes and changes in composition and use of the solutions. In addition, the literature is reviewed on ways of minimizing lens case microbial contamination. Maintaining the hygiene of contact lenses and lens cases is important in minimizing various forms of corneal infiltrative events that occur during lens wear. Although lens case contamination is not associated with different lenses, it is determined by use of different MPDS. MPDS that allow more frequent or heavy contamination of cases by Gram-negative bacteria are associated with a higher incidence of corneal infiltrative events. MPDS are now available that contain dual disinfectants. Wiping lens cases with tissues or using lens cases that incorporate silver are associated with reductions in contamination in clinical trials. Similarly, using MPDS to rub and rinse lenses before disinfection may reduce levels of microbes on lenses. The MPDS also contain surfactants that help reduce deposition and denaturation of proteins on lenses. Improvements in MPDS formulations and hygiene practices may help to reduce the incidence of adverse events that are seen during use with silicone hydrogel lenses.

  1. Sustained-release of FGF-2 from a hybrid hydrogel of heparin-poloxamer and decellular matrix promotes the neuroprotective effects of proteins after spinal injury

    Directory of Open Access Journals (Sweden)

    Xu HL

    2018-02-01

    Full Text Available  He-Lin Xu,1,* Fu-Rong Tian,1,* Jian Xiao,1,* Pian-Pian Chen,1 Jie Xu,1 Zi-Liang Fan,1 Jing-Jing Yang,1 Cui-Tao Lu,1 Ying-Zheng Zhao1,2 1Department of Pharmaceutics, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, 2Hainan Medical College, Haikou, China *These authors contributed equally to this work Introduction: The short lifetime of protein-based therapies has largely limited their therapeutic efficacy in injured nervous post-spinal cord injury (post-SCI. Methods: In this study, an affinity-based hydrogel delivery system provided sustained-release of proteins, thereby extending the efficacy of such therapies. The affinity-based hydrogel was constructed using a novel polymer, heparin-poloxamer (HP, as a temperature-sensitive bulk matrix and decellular spinal cord extracellular matrix (dscECM as an affinity depot of drug. By tuning the concentration of HP in formulation, the cold ternary fibroblast growth factor-2 (FGF2-dscECM-HP solution could rapidly gelatinize into a hydrogel at body temperature. Due to the strong affinity for FGF2, hybrid FGF2-dscECM-HP hydrogel enabled sustained-release of encapsulated FGF2 over an extended period in vitro. Results: Compared to free FGF2, it was observed that both neuron functions and tissue morphology after SCI were clearly recovered in rats treated with FGF2-dscECM-HP hydrogel. Moreover, the expression of neurofilament protein and the density of axons were increased after treatment with hybrid FGF2-dscECM-HP. In addition, the neuroprotective effects of FGF2-dscECM-HP were related to inhibition of chronic endoplasmic reticulum stress-induced apoptosis.Conclusion: The results revealed that a hybrid hydrogel system may be a potential carrier to deliver macromolecular proteins to the injured site and enhance the therapeutic effects of proteins.Keywords: spinal cord injury, decellularized extracellular matrix, thermosensitive hydrogel, adsorption, basic fibroblast growth factor

  2. Smart thermosensitive liposomes for effective solid tumor therapy and in vivo imaging.

    Directory of Open Access Journals (Sweden)

    Kevin Affram

    Full Text Available In numerous studies, liposomes have been used to deliver anticancer drugs such as doxorubicin to local heat-triggered tumor. Here, we investigate: (i the ability of thermosensitive liposomal nanoparticle (TSLnp as a delivery system to deliver poorly membrane-permeable anticancer drug, gemcitabine (Gem to solid pancreatic tumor with the aid of local mild hyperthermia and, (ii the possibility of using gadolinium (Magnevist® loaded-TSLnps (Gd-TSLnps to increase magnetic resonance imaging (MRI contrast in solid tumor. In this study, we developed and tested gemcitabine-loaded thermosensitive liposomal nanoparticles (Gem-TSLnps and gadolinium-loaded thermosensitive liposomal nanoparticles (Gd-TSLnps both in in-vitro and in-vivo. The TSLnps exhibited temperature-dependent release of Gem, at 40-42°C, 65% of Gem was released within 10 min, whereas < 23% Gem leakage occurred at 37°C after a period of 2 h. The pharmacokinetic parameters and tissue distribution of both Gem-TSLnps and Gd-TSLnps were significantly greater compared with free Gem and Gd, while Gem-TSLnps plasma clearance was reduced by 17-fold and that of Gd-TSLpns was decreased by 2-fold. Area under the plasma concentration time curve (AUC of Gem-TSLnps (35.17± 0.04 μghr/mL was significantly higher than that of free Gem (2.09 ± 0.01 μghr/mL whereas, AUC of Gd-TSLnps was higher than free Gd by 3.9 fold high. TSLnps showed significant Gem accumulation in heated tumor relative to free Gem. Similar trend of increased Gd-TSLnps accumulation was observed in non-heated tumor compared to that of free Gd; however, no significant difference in MRI contrast enhancement between free Gd and Gd-TSLnps ex-vivo tumor images was observed. Despite Gem-TSLnps dose being half of free Gem dose, antitumor efficacy of Gem-TSLnps was comparable to that of free Gem(Gem-TSLnps 10 mg Gem/kg compared with free Gem 20 mg/kg. Overall, the findings suggest that TSLnps may be used to improve Gem delivery and enhance

  3. Successful in vivo hyperthermal therapy toward breast cancer by Chinese medicine shikonin-loaded thermosensitive micelle

    Directory of Open Access Journals (Sweden)

    Su Y

    2017-05-01

    Full Text Available Yonghua Su,1,* Nian Huang,1,* Di Chen,2,* Li Zhang,2,* Xia Dong,2 Yun Sun,2 Xiandi Zhu,2 Fulei Zhang,2 Jie Gao,2 Ying Wang,2 Kexing Fan,2 Puichi Lo,3 Wei Li,2 Changquan Ling1 1Department of Integrative Oncology, Changhai Hospital of Traditional Chinese Medicine, 2International Joint Cancer Institute, The Second Military Medical University, Shanghai, 3Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong, China *These authors contributed equally to this work Abstract: The Chinese traditional medicine Shikonin is an ideal drug due to its multiple targets to tumor cells. But in clinics, improving its aqueous solubility and tumor accumulation is still a challenge. Herein, a copolymer with tunable poly(N-isopropylacrymaide and polylactic acid block lengths is designed, synthesized, and characterized in nuclear magnetic resonance. The corresponding thermosensitive nanomicelle (TN with well-defined core-shell structure is then assembled in an aqueous solution. For promoting the therapeutic index, the physical-chemistry properties of TNs including narrow size, low critical micellar concentration, high serum stability, tunable volume phase transition temperature (VPTT, high drug-loading capacity, and temperature-controlled drug release are systematically investigated and regulated through the fine self-assembly. The shikonin is then entrapped in a degradable inner core resulting in a shikonin-loaded thermosensitive nanomicelle (STN with a VPTT of ~40°C. Compared with small-molecular shikonin, the in vitro cellular internalization and cytotoxicity of STN against breast cancer cells (Michigan Cancer Foundation-7 are obviously enhanced. In addition, the therapeutic effect is further enhanced by the programmed cell death (PCD specifically evoked by shikonin. Interestingly, both the proliferation inhibition and PCD are synergistically promoted as T > VPTT, namely the temperature-regulated passive targeting. Consequently, as

  4. Genes associated with thermosensitive genic male sterility in rice identified by comparative expression profiling.

    Science.gov (United States)

    Pan, Yufang; Li, Qiaofeng; Wang, Zhizheng; Wang, Yang; Ma, Rui; Zhu, Lili; He, Guangcun; Chen, Rongzhi

    2014-12-16

    Thermosensitive genic male sterile (TGMS) lines and photoperiod-sensitive genic male sterile (PGMS) lines have been successfully used in hybridization to improve rice yields. However, the molecular mechanisms underlying male sterility transitions in most PGMS/TGMS rice lines are unclear. In the recently developed TGMS-Co27 line, the male sterility is based on co-suppression of a UDP-glucose pyrophosphorylase gene (Ugp1), but further study is needed to fully elucidate the molecular mechanisms involved. Microarray-based transcriptome profiling of TGMS-Co27 and wild-type Hejiang 19 (H1493) plants grown at high and low temperatures revealed that 15462 probe sets representing 8303 genes were differentially expressed in the two lines, under the two conditions, or both. Environmental factors strongly affected global gene expression. Some genes important for pollen development were strongly repressed in TGMS-Co27 at high temperature. More significantly, series-cluster analysis of differentially expressed genes (DEGs) between TGMS-Co27 plants grown under the two conditions showed that low temperature induced the expression of a gene cluster. This cluster was found to be essential for sterility transition. It includes many meiosis stage-related genes that are probably important for thermosensitive male sterility in TGMS-Co27, inter alia: Arg/Ser-rich domain (RS)-containing zinc finger proteins, polypyrimidine tract-binding proteins (PTBs), DEAD/DEAH box RNA helicases, ZOS (C2H2 zinc finger proteins of Oryza sativa), at least one polyadenylate-binding protein and some other RNA recognition motif (RRM) domain-containing proteins involved in post-transcriptional processes, eukaryotic initiation factor 5B (eIF5B), ribosomal proteins (L37, L1p/L10e, L27 and L24), aminoacyl-tRNA synthetases (ARSs), eukaryotic elongation factor Tu (eEF-Tu) and a peptide chain release factor protein involved in translation. The differential expression of 12 DEGs that are important for pollen

  5. Composites

    International Nuclear Information System (INIS)

    Kasen, M.B.

    1983-01-01

    This chapter discusses the roles of composite laminates and aggregates in cryogenic technology. Filamentary-reinforced composites are emphasized because they are the most widely used composite materials. Topics considered include composite systems and terminology, design and fabrication, composite failure, high-pressure reinforced plastic laminates, low-pressure reinforced plastics, reinforced metals, selectively reinforced structures, the effect of cryogenic temperatures, woven-fabric and random-mat composites, uniaxial fiber-reinforced composites, composite joints in cryogenic structures, joining techniques at room temperature, radiation effects, testing laminates at cryogenic temperatures, static and cyclic tensile testing, static and cyclic compression testing, interlaminar shear testing, secondary property tests, and concrete aggregates. It is suggested that cryogenic composite technology would benefit from the development of a fracture mechanics model for predicting the fitness-for-purpose of polymer-matrix composite structures

  6. Functionalized Nanolipobubbles Embedded Within a Nanocomposite Hydrogel: a Molecular Bio-imaging and Biomechanical Analysis of the System.

    Science.gov (United States)

    Mufamadi, Maluta S; Choonara, Yahya E; Kumar, Pradeep; du Toit, Lisa C; Modi, Girish; Naidoo, Dinesh; Iyuke, Sunny E; Pillay, Viness

    2017-04-01

    The purpose of this study was to explore the use of molecular bio-imaging systems and biomechanical dynamics to elucidate the fate of a nanocomposite hydrogel system prepared by merging FITC-labeled nanolipobubbles within a cross-linked hydrogel network. The nanocomposite hydrogel system was characterized by size distribution analysis and zeta potential as well as shears thinning behavior, elastic modulus (G'), viscous loss moduli (G"), TEM, and FTIR. In addition, molecular bio-imaging via Vevo ultrasound and Cell-viZio techniques evaluated the stability and distribution of the nanolipobubbles within the cross-linked hydrogel. FITC-labeled and functionalized nanolipobubbles had particle sizes between 135 and 158 nm (PdI = 0.129 and 0.190) and a zeta potential of -34 mV. TEM and ultrasound imaging revealed the uniformity and dimensional stability of the functionalized nanolipobubbles pre- and post-embedment into the cross-linked hydrogel. Biomechanical characterization of the hydrogel by shear thinning behavior was governed by the polymer concentration and the cross-linker, glutaraldehyde. Ultrasound analysis and Cell-viZio bio-imaging were highly suitable to visualize the fluorescent image-guided nanolipobubbles and their morphology post-embedment into the hydrogel to form the NanoComposite system. Since the nanocomposite is intended for targeted treatment of neurodegenerative disorders, the distribution of the functionalized nanolipobubbles into PC12 neuronal cells was also ascertained via confocal microscopy. Results demonstrated effective release and localization of the nanolipobubbles within PC12 neuronal cells. The molecular structure of the synthetic surface peptide remained intact for an extended period to ensure potency for targeted delivery from the hydrogel ex vivo. These findings provide further insight into the properties of nanocomposite hydrogels for specialized drug delivery.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  8. Development and Characterization of UHMWPE Fiber-Reinforced Hydrogels For Meniscal Replacement

    Science.gov (United States)

    Holloway, Julianne Leigh

    biocompatible PVA grafting technique was developed to form a direct covalent linkage at the fiber-matrix interface. Chemical grafting was tailored as a function of the number of sites available for covalent bonding and the percentage of sites reacted. PVA grafting resulted in significant improvements to interfacial shear strength from 11 kPa without any treatment to above 220 kPa following grafting. After grafting, failure was observed cohesively within the PVA hydrogel indicating the UHMWPE-PVA interface was successfully optimized. Lastly, in vitro gait simulations and an in vivo sheep study demonstrated the feasibility and biocompatibility of the proposed UHMWPE-PVA composite. The results from this work can be applied to designing materials for other soft tissue applications, including the anterior cruciate ligament (ACL) and the annulus fibrosus.

  9. Experimental Investigation of Mechanical and Thermal Properties of Silica Nanoparticle-Reinforced Poly(acrylamide) Nanocomposite Hydrogels.

    Science.gov (United States)

    Zaragoza, Josergio; Babhadiashar, Nasim; O'Brien, Victor; Chang, Andrew; Blanco, Matthew; Zabalegui, Aitor; Lee, Hohyun; Asuri, Prashanth

    2015-01-01

    Current studies investigating properties of nanoparticle-reinforced polymers have shown that nanocomposites often exhibit improved properties compared to neat polymers. However, over two decades of research, using both experimental studies and modeling analyses, has not fully elucidated the mechanistic underpinnings behind these enhancements. Moreover, few studies have focused on developing an understanding among two or more polymer properties affected by incorporation of nanomaterials. In our study, we investigated the elastic and thermal properties of poly(acrylamide) hydrogels containing silica nanoparticles. Both nanoparticle concentration and size affected hydrogel properties, with similar trends in enhancements observed for elastic modulus and thermal diffusivity. We also observed significantly lower swellability for hydrogel nanocomposites relative to neat hydrogels, consistent with previous work suggesting that nanoparticles can mediate pseudo crosslinking within polymer networks. Collectively, these results indicate the ability to develop next-generation composite materials with enhanced mechanical and thermal properties by increasing the average crosslinking density using nanoparticles.

  10. Chitosan–Cellulose Multifunctional Hydrogel Beads: Design, Characterization and Evaluation of Cytocompatibility with Breast Adenocarcinoma and Osteoblast Cells

    Science.gov (United States)

    Trivedi, Poonam; Saloranta-Simell, Tiina; Gradišnik, Lidija; Prabhakar, Neeraj; Smått, Jan-Henrik; Mohan, Tamilselvan; Gericke, Martin; Heinze, Thomas

    2018-01-01

    Cytocompatible polysaccharide-based functional scaffolds are potential extracellular matrix candidates for soft and hard tissue engineering. This paper describes a facile approach to design cytocompatible, non-toxic, and multifunctional chitosan-cellulose based hydrogel beads utilising polysaccharide dissolution in sodium hydroxide-urea-water solvent system and coagulation under three different acidic conditions, namely 2 M acetic acid, 2 M hydrochloric acid, and 2 M sulfuric acid. The effect of coagulating medium on the final chemical composition of the hydrogel beads is investigated by spectroscopic techniques (ATR–FTIR, Raman, NMR), and elemental analysis. The beads coagulated in 2 M acetic acid displayed an unchanged chitosan composition with free amino groups, while the beads coagulated in 2 M hydrochloric and sulfuric acid showed protonation of amino groups and ionic interaction with the counterions. The ultrastructural morphological study of lyophilized beads showed that increased chitosan content enhanced the porosity of the hydrogel beads. Furthermore, cytocompatibility evaluation of the hydrogel beads with human breast adenocarcinoma cells (soft tissue) showed that the beads coagulated in 2 M acetic acid are the most suitable for this type of cells in comparison to other coagulating systems. The acetic acid fabricated hydrogel beads also support osteoblast growth and adhesion over 192 h. Thus, in future, these hydrogel beads can be tested in the in vitro studies related to breast cancer and for bone regeneration. PMID:29315214

  11. Chitosan-Cellulose Multifunctional Hydrogel Beads: Design, Characterization and Evaluation of Cytocompatibility with Breast Adenocarcinoma and Osteoblast Cells.

    Science.gov (United States)

    Trivedi, Poonam; Saloranta-Simell, Tiina; Maver, Uroš; Gradišnik, Lidija; Prabhakar, Neeraj; Smått, Jan-Henrik; Mohan, Tamilselvan; Gericke, Martin; Heinze, Thomas; Fardim, Pedro

    2018-01-09

    Cytocompatible polysaccharide-based functional scaffolds are potential extracellular matrix candidates for soft and hard tissue engineering. This paper describes a facile approach to design cytocompatible, non-toxic, and multifunctional chitosan-cellulose based hydrogel beads utilising polysaccharide dissolution in sodium hydroxide-urea-water solvent system and coagulation under three different acidic conditions, namely 2 M acetic acid, 2 M hydrochloric acid, and 2 M sulfuric acid. The effect of coagulating medium on the final chemical composition of the hydrogel beads is investigated by spectroscopic techniques (ATR-FTIR, Raman, NMR), and elemental analysis. The beads coagulated in 2 M acetic acid displayed an unchanged chitosan composition with free amino groups, while the beads coagulated in 2 M hydrochloric and sulfuric acid showed protonation of amino groups and ionic interaction with the counterions. The ultrastructural morphological study of lyophilized beads showed that increased chitosan content enhanced the porosity of the hydrogel beads. Furthermore, cytocompatibility evaluation of the hydrogel beads with human breast adenocarcinoma cells (soft tissue) showed that the beads coagulated in 2 M acetic acid are the most suitable for this type of cells in comparison to other coagulating systems. The acetic acid fabricated hydrogel beads also support osteoblast growth and adhesion over 192 h. Thus, in future, these hydrogel beads can be tested in the in vitro studies related to breast cancer and for bone regeneration.

  12. Microsphere erosion in outer hydrogel membranes creating macroscopic porosity to counter biofouling-induced sensor degradation.

    Science.gov (United States)

    Vaddiraju, S; Wang, Y; Qiang, L; Burgess, D J; Papadimitrakopoulos, F

    2012-10-16

    Biofouling and tissue inflammation present major challenges toward the realization of long-term implantable glucose sensors. Following sensor implantation, proteins and cells adsorb on sensor surfaces to not only inhibit glucose flux but also signal a cascade of inflammatory events that eventually lead to permeability-reducing fibrotic encapsulation. The use of drug-eluting hydrogels as outer sensor coatings has shown considerable promise to mitigate these problems via the localized delivery of tissue response modifiers to suppress inflammation and fibrosis, along with reducing protein and cell absorption. Biodegradable poly (lactic-co-glycolic) acid (PLGA) microspheres, encapsulated within a poly (vinyl alcohol) (PVA) hydrogel matrix, present a model coating where the localized delivery of the potent anti-inflammatory drug dexamethasone has been shown to suppress inflammation over a period of 1-3 months. Here, it is shown that the degradation of the PLGA microspheres provides an auxiliary venue to offset the negative effects of protein adsorption. This was realized by: (1) the creation of fresh porosity within the PVA hydrogel following microsphere degradation (which is sustained until the complete microsphere degradation) and (2) rigidification of the PVA hydrogel to prevent its complete collapse onto the newly created void space. Incubation of the coated sensors in phosphate buffered saline (PBS) led to a monotonic increase in glucose permeability (50%), with a corresponding enhancement in sensor sensitivity over a 1 month period. Incubation in serum resulted in biofouling and consequent clogging of the hydrogel microporosity. This, however, was partially offset by the generated macroscopic porosity following microsphere degradation. As a result of this, a 2-fold recovery in sensor sensitivity for devices with microsphere/hydrogel composite coatings was observed as opposed to similar devices with blank hydrogel coatings. These findings suggest that the use of

  13. Evaluation of Photocrosslinked Lutrol Hydrogel for Tissue Printing applications

    NARCIS (Netherlands)

    Fedorovich, Natalja E.; Swennen, Ives; Girones, Jordi; Moroni, Lorenzo; van Blitterswijk, Clemens; Schacht, Etienne; Alblas, Jacqueline; Dhert, Wouter J.A.

    2009-01-01

    Application of hydrogels in tissue engineering and innovative strategies such as organ printing, which is based on layered 3D deposition of cell-laden hydrogels, requires design of novel hydrogel matrices. Hydrogel demands for 3D printing include: 1) preservation of the printed shape after the

  14. Chemically Crosslinked Hydrogel Film Leads to Integrated Flexible Supercapacitors with Superior Performance.

    Science.gov (United States)

    Wang, Kai; Zhang, Xiong; Li, Chen; Sun, Xianzhong; Meng, Qinghai; Ma, Yanwei; Wei, Zhixiang

    2015-12-02

    A high-strength poly(vinyl alcohol) chemical hydrogel (PCH) film is prepared by coupling covalent crosslinking with a film-casting process. Conducting polyaniline (PANI) is then embedded in the PCH film by in situ growth to form a composite film with a PANI-hydrogel-PANI configuration, which leads to a new conceptual flexible supercapacitor with all-in-one configuration that exhibits superior electrochemical performance and mechanical flexibility. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Dialing in the Ratio of Covalent and Coordination Cross-links in Self-healing Hydrogels

    DEFF Research Database (Denmark)

    Andersen, Amanda; Krogsgaard, Marie; Birkedal, Henrik

    -linking and as these impacts the abovementioned properties, it is of great interest to control the degree of which these are present; i.e. controlling the degree of catechol oxidation. Until now, the catechols participating in the two cross-linking types have been the same. This way the actual ratio between the two types...... cannot be either predefined or controlled, as it is determined by the oxidation rate within the hydrogel. Here, we report hydrogels in which the catechols participating in reversible (oxidation resistant catechol) and irreversible (classical catechol) cross-links are separated, enabling one to predefine...... the ratio of the two by altering the composition....

  16. Graphene hydrogels deposited in nickel foams for high-rate electrochemical capacitors.

    Science.gov (United States)

    Chen, Ji; Sheng, Kaixuan; Luo, Peihui; Li, Chun; Shi, Gaoquan

    2012-08-28

    Graphene hydrogel/nickel foam composite electrodes for high-rate electrochemical capacitors are produced by reduction of an aqueous dispersion of graphene oxide in a nickel foam (upper half of figure). The micropores of the hydrogel are exposed to the electrolyte so that ions can enter and form electrochemical double-layers. The nickel framework shortens the distances of charge transfer. Therefore, the electrochemical capacitor exhibits highrate performance (see plots). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. A thermo-sensitive purple leaf rice mutant--PLM12 and its genetical study

    International Nuclear Information System (INIS)

    Wu Guanting; Wang Xianyu; Jin Wei

    2001-01-01

    PLM12 was a thermo-sensitive purple leaf mutant selected from Indica rice variety Luqingzao 1 treated with pingyangmycin in combination with γ-rays, and for display of its mutant character, a relatively high temperature was required. Compared with its original parent, many major agronomic traits of PLM12 changed to varied extents. Based on spikelet cutting experiment, it was believed that significant decreases in number of filled grains per panicle, fertility, and 1000-grain weight in PLM12 resulted mainly from a great decline in photosynthetic capacity and serious lack of photosynthate in purple leaves. It was indicated by genetic analysis that expression of the mutant phenotype in PLM12 was conditioned by a single recessive major nuclear gene and modified by several minor genes

  18. Investigating hydrogel dosimeter decomposition by chemical methods

    International Nuclear Information System (INIS)

    Jordan, Kevin

    2015-01-01

    The chemical oxidative decomposition of leucocrystal violet micelle hydrogel dosimeters was investigated using the reaction of ferrous ions with hydrogen peroxide or sodium bicarbonate with hydrogen peroxide. The second reaction is more effective at dye decomposition in gelatin hydrogels. Additional chemical analysis is required to determine the decomposition products

  19. Thermal Transport in Soft PAAm Hydrogels

    Directory of Open Access Journals (Sweden)

    Ni Tang

    2017-12-01

    Full Text Available As the interface between human and machine becomes blurred, hydrogel incorporated electronics and devices have emerged to be a new class of flexible/stretchable electronic and ionic devices due to their extraordinary properties, such as softness, mechanically robustness, and biocompatibility. However, heat dissipation in these devices could be a critical issue and remains unexplored. Here, we report the experimental measurements and equilibrium molecular dynamics simulations of thermal conduction in polyacrylamide (PAAm hydrogels. The thermal conductivity of PAAm hydrogels can be modulated by both the effective crosslinking density and water content in hydrogels. The effective crosslinking density dependent thermal conductivity in hydrogels varies from 0.33 to 0.51 Wm−1K−1, giving a 54% enhancement. We attribute the crosslinking effect to the competition between the increased conduction pathways and the enhanced phonon scattering effect. Moreover, water content can act as filler in polymers which leads to nearly 40% enhancement in thermal conductivity in PAAm hydrogels with water content vary from 23 to 88 wt %. Furthermore, we find the thermal conductivity of PAAm hydrogel is insensitive to temperature in the range of 25–40 °C. Our study offers fundamental understanding of thermal transport in soft materials and provides design guidance for hydrogel-based devices.

  20. Highly Stretchable, Strain Sensing Hydrogel Optical Fibers.

    Science.gov (United States)

    Guo, Jingjing; Liu, Xinyue; Jiang, Nan; Yetisen, Ali K; Yuk, Hyunwoo; Yang, Changxi; Khademhosseini, Ali; Zhao, Xuanhe; Yun, Seok-Hyun

    2016-12-01

    A core-clad fiber made of elastic, tough hydrogels is highly stretchable while guiding light. Fluorescent dyes are easily doped into the hydrogel fiber by diffusion. When stretched, the transmission spectrum of the fiber is altered, enabling the strain to be measured and also its location. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Biomolecule-Responsive Hydrogels in Medicine.

    Science.gov (United States)

    Sharifzadeh, Ghorbanali; Hosseinkhani, Hossein

    2017-12-01

    Recent advances and applications of biomolecule-responsive hydrogels, namely, glucose-responsive hydrogels, protein-responsive hydrogels, and nucleic-acid-responsive hydrogels are highlighted. However, achieving the ultimate purpose of using biomolecule-responsive hydrogels in preclinical and clinical areas is still at the very early stage and calls for more novel designing concepts and advance ideas. On the way toward the real/clinical application of biomolecule-responsive hydrogels, plenty of factors should be extensively studied and examined under both in vitro and in vivo conditions. For example, biocompatibility, biointegration, and toxicity of biomolecule-responsive hydrogels should be carefully evaluated. From the living body's point of view, biocompatibility is seriously depended on the interactions at the tissue/polymer interface. These interactions are influenced by physical nature, chemical structure, surface properties, and degradation of the materials. In addition, the developments of advanced hydrogels with tunable biological and mechanical properties which cause no/low side effects are of great importance. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Synthesis and characterization of superabsorbent hydrogel based ...

    African Journals Online (AJOL)

    The hydrogels structure was characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The effect of grafting variables, that is, AA/AN weight ratio and concentration of MBA and APS, was systematically optimized to achieve a hydrogel with ...

  3. Cross-Linked Hydrogel for Pharmaceutical Applications: A Review

    Directory of Open Access Journals (Sweden)

    Rabinarayan parhi

    2017-12-01

    Full Text Available Hydrogels are promising biomaterials because of their important qualities such as biocompatibility, biodegradability, hydrophilicity and non-toxicity. These qualities make hydrogels suitable for application in medical and pharmaceutical field. Recently, a tremendous growth of hydrogel application is seen, especially as gel and patch form, in transdermal drug delivery. This review mainly focuses on the types of hydrogels based on cross-linking and; secondly to describe the possible synthesis methods to design hydrogels for different pharmaceutical applications. The synthesis and chemistry of these hydrogels are discussed using specific pharmaceutical examples. The structure and water content in a typical hydrogel have also been discussed.

  4. Clampless anastomosis with an intraluminal thermosensitive gel: first application in reconstructive microsurgery and literature review.

    Science.gov (United States)

    Giessler, G A; Fischborn, G T; Schmidt, A B

    2012-01-01

    Microvascular clamps of various designs provide a bloodless field for a safe anastomosis but can cause intimal lesions, occupy space in confined sites and have a risk of backwalling due to vessel flattening. They are often insufficient in their haemostatic effect in plaque-filled atherosclerotic vessels. A new, CE-certified thermosensitive gel (LeGoo™) clinically proven in cardiovascular surgery allows a clampless microanastomosis technique. We operated on a series of five consecutive patients aged 24-71 years with six flaps for lower-extremity reconstruction using a clampless anastomosis technique with LeGoo™. We transplanted one fabricated chimaeric fibula plus gracilis, three gracilis muscle and one anterolateral thigh (ALT) flap. Pre- and postoperative protocols were similar to a 'standard' procedure with micro-clamps. All flaps survived completely except for a small area on fibula skin island, which was unrelated to gel use. The gel-assisted technique has a quick learning curve, according to this case series. The veins should be sutured first to prevent stasis in the flap. The gel provides circular stenting and gentle distension of the vessels for a safe and blood-free anastomotic site. It is completely dissolved after completion of the anastomosis with cold saline irrigation. Repolymerisation in the periphery will not occur, making it safe for microvascular flap surgery. From the experiences from this series and other specialities, the use of the thermosensitive gel LeGoo™ permits a safe clampless microanastomosis technique minimising mechanical vessel manipulation and compression. This makes it an attractive alternative to micro-clamps, especially for atherosclerotic arteries and confined anastomosis sites. Copyright © 2011 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  5. Preparation of thermosensitive magnetic liposome encapsulated recombinant tissue plasminogen activator for targeted thrombolysis

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Hao-Lung [Department of Chemical and Materials Engineering, Chang Gung University, Kwei-San, Taoyuan 33302, Taiwan, ROC (China); Chen, Jyh-Ping, E-mail: jpchen@mail.cgu.edu.tw [Department of Chemical and Materials Engineering, Chang Gung University, Kwei-San, Taoyuan 33302, Taiwan, ROC (China); Department of Plastic and Reconstructive Surgery and Craniofacial Research Center, Chang Gung Memorial Hospital, Kwei-San, Taoyuan 33305, Taiwan, ROC (China); Graduate Institute of Health Industry and Technology, Research Center for Industry of Human Ecology, Chang Gung University of Science and Technology, Kwei-San, Taoyuan 33302, Taiwan, ROC (China); Department of Materials Engineering, Ming Chi University of Technology, Tai-Shan, New Taipei City 24301, Taiwan, ROC (China)

    2017-04-01

    Recombinant tissue plasminogen activator (rtPA) was encapsulated in thermosensitive magnetic liposome (TML) prepared from 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, distearolyphosphatidyl ethanolamine-N-poly(ethylene glycol) 2000, cholesterol and Fe{sub 3}O{sub 4} magnetic nanoparticles by solvent evaporation/sonication and freeze-thaw cycles method. Response surface methodology was proved to be a powerful tool to predict the drug encapsulation efficiency and temperature-sensitive drug release. Validation experiments verified the accuracy of the model that provides a simple and effective method for fabricating TML with controllable encapsulation efficiency and predictable temperature-sensitive drug release behavior. The prepared samples were characterized for physico-chemical properties by dynamic light scattering, transmission electron microscopy, X-ray diffraction and differential scanning calorimetry. Temperature-sensitive release of rtPA could be confirmed from in vitro thrombolysis experiments. A thrombolytic drug delivery system using TML could be proposed for magnetic targeted delivery of rtPA to the site of thrombus followed by temperature-triggered controlled drug release in an alternating magnetic field. - Highlights: • rtPA and Fe{sub 3}O{sub 4} MNP were encapsulated in thermosensitive magnetic liposome (TML). • RSM could predict the drug encapsulation efficiency and temperature-sensitive drug release from TML. • Temperature-sensitive release of rtPA was confirmed from in vitro thrombolysis experiments. • TML-rtPA will be useful as a magnetic targeted nanodrug to improve clinical thrombolytic therapy.

  6. Preparation and Evaluation of Oxaliplatin Thermosensitive Liposomes with Rapid Release and High Stability.

    Directory of Open Access Journals (Sweden)

    Chunying Zeng

    Full Text Available Oxaliplatin (OXP was reported to show low anti-tumor activity when used alone and to display side effects; this low activity was attributed to high partitioning to erythrocytes and low accumulation in tumors. Thermosensitive liposomes (TSL were considered able to specifically deliver drugs to heated tumors and to resolve the OXP distribution problem. Regretfully, TSL encapsulating doxorubicin did not demonstrate significant improvement in progression-free survival. Drug release below 41°C and significant leakage were considered major reasons for the failure. The purpose of this study was to acquire OXP TSL with rapid release at the triggered temperature and high stability at body temperature and at storage temperatures. A small quantity of poloxamer 188 was introduced into the TSL formulation to stabilize the encapsulated drug. It was shown that the addition of poloxamer 188 had no influence on the TSL characteristics. More than 90% of OXP was released within 10 min at 42°C, and less than 15% was released within 60 min at temperatures below 39°C. TSL were stable at 37°C for 96 h and at 4°C for 6 months. The anti-tumor activity of TSL at the dose of 2.5 mg/kg was certified to be equal to those of OXP injection and non-thermosensitive liposomes (NTSL at the dose of 5 mg/kg, and significant improvement of tumor inhibition was observed in TSL compared with injection and NTSL at the same dose. It was also shown from the histological transmutation of tumors that TSL had stronger anti-tumor activity. Therefore, it could be concluded that TSL composed of a proper amount of poloxamer had rapid release and high stability, and OXP TSL would be anticipated to exert prominent anti-tumor activity in the clinic.

  7. Indirect hand and forearm vasomotion: Regional variations in cutaneous thermosensitivity during normothermia and mild hyperthermia.

    Science.gov (United States)

    Burdon, Catriona A; Tagami, Kyoko; Park, Joonhee; Caldwell, Joanne N; Taylor, Nigel A S

    2017-04-01

    In this experiment, hand and forearm vasomotor activity was investigated during localised, but stable heating and cooling of the face, hand and thigh, under open-loop (clamped) conditions. It was hypothesised that facial stimulation would provoke the most potent vascular changes. Nine individuals participated in two normothermic trials (mean body temperature clamp: 36.6°C; water-perfused suit and climate chamber) and two mildly hyperthermic trials (37.9°C). Localised heating (+5°C) and cooling (-5°C) stimuli were applied to equal surface areas of the face, hand and thigh (perfusion patches: 15min), while contralateral forearm or hand blood flows (venous-occlusion plethysmography) were measured (separate trials). Thermal sensation and discomfort votes were recorded before and during each thermal stimulation. When hyperthermic, local heating induced more sensitive vascular responses, with the combined thermosensitivity of both limb segments averaging 0.011mL·100mL -1 ·min -1 ·mmHg -1 ·°C -1 , and 0.005mL·100mL -1 ·min -1 ·mmHg -1 ·°C -1 during localised cooling (P0.05). Therefore, regional differences in vasomotor and sensory sensitivity appeared not to exist. When combined with previous observations of sudomotor sensitivity, it seems that, during mild heating and cooling, regional representations within the somatosensory cortex may not translate into meaningful differences in thermal sensation or the central integration of thermoafferent signals. It was concluded that inter-site variations in the cutaneous thermosensitivity of these thermolytic effectors have minimal physiological significance over the ranges investigated thus far. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. A phytomodulatory hydrogel with enhanced healing effects.

    Science.gov (United States)

    Vasconcelos, Mirele S; Souza, Tamiris F G; Figueiredo, Ingrid S; Sousa, Emília T; Sousa, Felipe D; Moreira, Renato A; Alencar, Nylane M N; Lima-Filho, José V; Ramos, Márcio V

    2018-04-01

    The healing performance of a hydrogel composed of hemicelluloses extracted from seeds of Caesalpinia pulcherrima (Fabaceae) and mixed with phytomodulatory proteins obtained from the latex of Calotropis procera was characterized on excisional wounds. The hydrogel did not induce dermal irritability. When topically used on excisional wounds, the hydrogel enhanced healing by wound contraction. Histology and the measurement of inflammatory mediators (myeloperoxidase, interleukin-1β, and interleukin-6) suggested that the inflammatory phase of the healing process was intensified, stimulating fibroplasia and neovascularization (proliferative phase) and tissue remodeling by increasing new collagen fiber deposition. In addition, reduction on levels of malondialdehyde in the groups that the hydrogel was applied suggested that the oxidative stress was reduced. The hydrogel performed better than the reference drug used, as revealed by the extended thickness of the remodeled epithelium. Copyright © 2018 John Wiley & Sons, Ltd.

  9. Arct'Alg release from hydrogel membranes

    International Nuclear Information System (INIS)

    Amaral, Renata H.; Rogero, Sizue O.; Shihomatsu, Helena M.; Lugao, Ademar B.

    2009-01-01

    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 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 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 R was released from PVP and PVA hydrogel membrane devices respectively. (author)

  10. Hybrid hydrogels produced by ionizing radiation technique

    Science.gov (United States)

    Oliveira, M. J. A.; Amato, V. S.; Lugão, A. B.; Parra, D. F.

    2012-09-01

    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.

  11. Dialing in the Ratio of Covalent and Coordination Cross-links in Self-healing Hydrogels

    DEFF Research Database (Denmark)

    Andersen, Amanda; Krogsgaard, Marie; Birkedal, Henrik

    ; it is of great interest to control the degree of which these are present; i.e. controlling the degree of catechol oxidation. Here, we report hydrogels in which the catechols participating in reversible (oxidation resistant catechol-analogue6) and irreversible oxidation cross-links are separated, enabling one...... to predefine the ratio of the two by altering the composition. The oxidation-resistant catechol-analogue was grafted onto polyallylamine,4 while the oxidation cross-links are introduced by addition of tannic acid that has the same useful properties as catechols.5,7,8 This affords hydrogels that retain self......-healing abilities even at high pH but that can be stiffened at will by dialing in the required degree of covalent crosslinking. This dial-in method thus harnesses two aspects of catechol-type chemistries to yield double network hydrogels in a straightforward and highly controllable manner....

  12. Fibrin hydrogels to deliver dental stem cells of the apical papilla for regenerative medicine.

    Science.gov (United States)

    Germain, Loïc; De Berdt, Pauline; Vanacker, Julie; Leprince, Julian; Diogenes, Anibal; Jacobs, Damien; Vandermeulen, Gaëlle; Bouzin, Caroline; Préat, Véronique; Dupont-Gillain, Christine; des Rieux, Anne

    2015-01-01

    Evaluation of survival, proliferation and neurodifferentiation of dental stem cells from the apical papilla (SCAP) in fibrin hydrogels. We hypothesized that fibrin composition will influence cell behavior. Modulus, pore and fiber size were measured. SCAP in vitro viability, proliferation and neural differentiation, as well as in vivo proliferation and angiogenesis were studied. Hydrogel moduli were influenced by fibrin formulation but not hydrogel morphology, SCAP in vitro viability and proliferation. In total 60% of SCAP expressed PanNeurofilament in vitro without induction in Fibrinogen50-Thrombin10. SCAP proliferated when implanted in vivo and stimulated host endothelial cell infiltration. Fibrinogen30-Thrombin10 or Thrombin50 would be more favorable to in vitro SCAP viability and in vivo proliferation, while Fibrinogen 50-Thrombin50 would be more adapted to neurodifferentiation.

  13. Tragacanth gum/nano silver hydrogel on cotton fabric: In-situ synthesis and antibacterial properties.

    Science.gov (United States)

    Montazer, M; Keshvari, A; Kahali, P

    2016-12-10

    This paper is mainly focused on introducing cotton fabric with hydrogel and antimicrobial properties using Tragacanth gum as a natural polymer with hydrogel properties, silver nitrate as silver precursor, citric acid as a cross-linking agent and sodium hypophosphite as catalyst. The water absorption behavior of the treated fabrics was investigated with moisture regain, water retention, drying time of wetted fabric at room condition and vertical wicking tests. Antibacterial properties of the samples were evaluated against Escherichia coli and Staphylococcous aureus. The SEM pictures confirmed formation of nano silver and hydrogel layer on the fabric surface and XRD performed the crystal and particle size of the nano silver. The chemical structure of the fabric samples was identified with FTIR spectra. The central composite design (CCD) was used for statistical modelling, evaluated effective parameters and created optimum conditions. The treated cotton fabrics showed good water absorption properties along with reasonable antibacterial effectiveness. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. In vivo evaluation of the bone integration of coated poly(vinyl-alcohol) hydrogel fiber implants.

    Science.gov (United States)

    Moreau, David; Villain, Arthur; Bachy, Manon; Proudhon, Henry; Ku, David N; Hannouche, Didier; Petite, Hervé; Corté, Laurent

    2017-08-01

    Recently, it has been shown that constructs of poly(vinyl alcohol) (PVA) hydrogel fibers reproduce closely the tensile behavior of ligaments. However, the biological response to these systems has not been explored yet. Here, we report the first in vivo evaluation of these implants and focus on the integration in bone, using a rabbit model of bone tunnel healing. Implants consisted in bundles of PVA hydrogel fibers embedded in a PVA hydrogel matrix. Half of the samples were coated with a composite coating of hydroxyapatite (HA) particles embedded in PVA hydrogel. The biological integration was evaluated at 6 weeks using histology and micro-CT imaging. For all implants, a good biological tolerance and growth of new bone tissue are reported. All the implants were surrounded by a fibrous layer comparable to what was previously observed for poly(ethylene terephthalate) (PET) fibers currently used in humans for ligament reconstruction. An image analysis method is proposed to quantify the thickness of this fibrous capsule. Implants coated with HA were not significantly osteoconductive, which can be attributed to the slow dissolution of the selected hydroxyapatite. Overall, these results confirm the relevance of PVA hydrogel fibers for ligament reconstruction and adjustments are proposed to enhance its osseointegration.

  15. Engineering Enriched Microenvironments with Gradients of Platelet Lysate in Hydrogel Fibers.

    Science.gov (United States)

    Santo, Vítor E; Babo, Pedro; Amador, Miguel; Correia, Cláudia; Cunha, Bárbara; Coutinho, Daniela F; Neves, Nuno M; Mano, João F; Reis, Rui L; Gomes, Manuela E

    2016-06-13

    Gradients of physical and chemical cues are characteristic of specific tissue microenvironments and contribute toward morphogenesis and tissue regeneration upon injury. Recent advances on microfluidics and hydrogel manipulation raised the possibility of generating biomimetic biomaterials enriched with bioactive factors and encapsulating cells following designs specifically tailored for a target application. The novelty of this work relies on the combination of methacrylated gellan gum (MeGG) with platelet lysate (PL), aiming to generate novel advanced 3D PL-enriched photo-cross-linkable hydrogels and overcoming the lack of adhesion sites provided by the native MeGG hydrogels. This combination takes advantage of the availability, enriched growth factor composition, and potential autologous application of PL while simultaneously preserving the ability provided by MeGG to tailor mechanical properties, protein release kinetics, and shape of the construct according to the desired goal. Incorporation of PL in the hydrogels significantly improved cellular adhesion and viability in the constructs. The use of microfluidic tools allowed the design of a fiber-like hydrogel incorporating a gradient of PL along the length of the fiber. These spatial protein gradients led to the viability and cell number gradients caused by maintenance of human umbilical vein endothelial cells (HUVECs) survival in the fibers toward the PL-enriched sections in comparison with the nonloaded MeGG sections of the fibers. Altogether, we propose a proof of concept strategy to design a PL gradient biomaterial with potential in tissue engineering approaches and analysis of cell-microenvironment interactions.

  16. Biomimetic hydrogels for biosensor implant biocompatibility: electrochemical characterization using micro-disc electrode arrays (MDEAs).

    Science.gov (United States)

    Justin, Gusphyl; Finley, Stephen; Abdur Rahman, Abdur Rub; Guiseppi-Elie, Anthony

    2009-02-01

    Our interest is in the development of engineered microdevices for continuous remote monitoring of intramuscular lactate, glucose, pH and temperature during post-traumatic hemorrhaging. Two important design considerations in the development of such devices for in vivo diagnostics are discussed; the utility of micro-disc electrode arrays (MDEAs) for electrochemical biosensing and the application of biomimetic, bioactive poly(HEMA)-based hydrogel composites for implant biocompatibility. A poly(HEMA)-based hydrogel membrane containing polyethylene glycol (PEG) was UV cross-linked with tetraethyleneglycol diacrylate following application to MDEAs (50 mum discs) and to 250 mum diameter gold electrodes within 8-well culture ware. Cyclic voltammetry (CV) of the MDEAs revealed a reduction in the apparent diffusion coefficient of ferrocenemonocarboxylic acid (FcCO(2)H), from 6.68 x 10(-5) to 6.74 x 10(-6) cm(2)/s for the uncoated and 6 mum thick hydrogel coated devices, respectively. Single frequency (4 kHz) temporal impedance measurements of the hydrogels in the 8-well culture ware showed a reversible 5% change in the absolute impedance of the hydrogels when exposed to a pH change between 6.1 to 7.2 and a 20% drop between pH 6.1 and 8.8.

  17. Composition

    DEFF Research Database (Denmark)

    Bergstrøm-Nielsen, Carl

    2011-01-01

    Strategies are open compositions to be realised by improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound files will in some cases only provide a few minutes' sample. Please DOWNLOAD them to hear them in full...

  18. Composition

    DEFF Research Database (Denmark)

    2014-01-01

    Memory Pieces are open compositions to be realised solo by an improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound files will in some cases only provide a few minutes' sample. Please DOWNLOAD them to hear them...

  19. Kinetic and theoretical studies of novel biodegradable thermo-sensitive xerogels based on PEG/PVP/silica for sustained release of enrofloxacin

    Science.gov (United States)

    Ebadi, Azra; Rafati, Amir Abbas; Bavafa, Sadeghali; Mohammadi, Masoumah

    2017-12-01

    This study involves the synthesis of a new silica-based colloidal hybrid system. In this new hybrid system, poly (ethylene glycol) (PEG) and thermo-sensitive amphiphilic biocompatible poly (vinyl pyrrolidone) (PV