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Showing papers on "Gelatin published in 2002"


Journal ArticleDOI
TL;DR: Circular dichroism analysis reveals that gelling involves a refolding of denatured collagen chains into the typical triple helix conformation and, conversely, unfolding upon reheating, and the importance of slow cold maturation is revealed.

768 citations


Journal ArticleDOI
TL;DR: The mechanical, thermal and swelling properties of the films are very close to those previously obtained for glutaraldehyde crosslinked gelatin, and suggest that genipin, which is by far less cytotoxic, can be considered a valid alternative for crosslinking gelatin biomaterials.

548 citations


Journal ArticleDOI
TL;DR: The results of this study show that PEGylation of gelatin may prove beneficial as long-circulating delivery system in vivo and could encapsulate hydrophilic macromolecules and are internalized by tumor cells.
Abstract: Purpose. The objective of this study was to develop and characterize long-circulating, biodegradable, and biocompatible nanoparticulate formulation as an intracellular delivery vehicle.

285 citations


Journal ArticleDOI
TL;DR: The endothelial cell culture proved that the PCL membrane slightly modified with suitable amount of PMAA or gelatin had better cytocompatibility than control PCL orPCL membrane heavily modified with PMAAor gelatin.

213 citations


Journal ArticleDOI
10 Jul 2002-Langmuir
TL;DR: This series of two papers investigated gelatin samples from various origins, mammalian and fish gelatins, with the aim of comparing their properties to the reference samples generally used in photographic and food applications.
Abstract: Gelatin gels are well-known for their ability to form nonpermanent, physical gels at room temperature and for their numerous applications in photographic and food industries. The difficulties in un...

206 citations


Journal ArticleDOI
TL;DR: It is demonstrated that tyrosinase can be exploited for the in vitro formation of protein-polysaccharide conjugates that offer interesting mechanical properties.
Abstract: The enzyme tyrosinase was used for the in vitro conjugation of the protein gelatin to the polysaccharide chitosan. Tyrosinases are oxidative enzymes that convert accessible tyrosine residues of proteins into reactive o-quinone moieties. Spectrophotometric and dissolved oxygen studies indicate that tyrosinase can oxidize gelatin and we estimate that 1 in 5 gelatin chains undergo reaction. Oxidized tyrosyl residues (i.e., quinone residues) can undergo nonenzymatic reactions with available nucleophiles such as the nucleophilic amino groups of chitosan. Ultraviolet/visible, (1)H-NMR, and ir provided chemical evidence for the conjugation of oxidized gelatin with chitosan. Physical evidence for conjugation was provided by dynamic viscometry, which indicated that tyrosinase catalyzes the sol-to-gel conversion of gelatin/chitosan mixtures. The gels formed from tyrosinase-catalyzed reactions were observed to differ from gels formed by cooling gelatin. In contrast to gelatin gels, tyrosinase-generated gels had different thermal behavior and were broken by the chitosan-hydrolyzing enzyme chitosanase. These results demonstrate that tyrosinase can be exploited for the in vitro formation of protein-polysaccharide conjugates that offer interesting mechanical properties.

186 citations


Journal ArticleDOI
TL;DR: This study aimed at the development of a method to fabricate porous spherical hydroxyapatite granules, which can be impregnated with a drug, to be used as a system for targeted and time-controlled drug delivery, e.g. in bone surgery.

179 citations


Journal ArticleDOI
TL;DR: In the hydrogel system, active plasmid DNA was released accompanied with the in vivo degradation of hydrogels, resulting in extended gene expression, controllable by changing the water content ofhydrogels.

163 citations


Journal ArticleDOI
TL;DR: An attempt was made to prepare the composite microspheres containing coralline hydroxyapatite and gelatin (CHA-G), which were prepared by the dispersion polymerization technique and the gentamicin was incorporated by the absorption method.

159 citations


Journal ArticleDOI
TL;DR: It was demonstrated that the immobilized enzyme could be used repeatedly, after intermittent storage, for production of L-DOPA (3,4-dihydroxyphenylalanine) and Cu-alginate entrapped tryosinase was found to be superior in this regard.

151 citations


Journal ArticleDOI
TL;DR: Biodegradable hydrophilic gelatin nanoparticles, containing different initial amounts of methotrexate (MTX), were prepared using a simple solvent evaporation technique based on a single water-in-oil emulsion and stabilized by the use of glutaraldehyde as cross-linking agent.
Abstract: Biodegradable hydrophilic gelatin nanoparticles, containing different initial amounts of methotrexate (MTX), were prepared using a simple solvent evaporation technique based on a single water-in-oil emulsion and stabilized by the use of glutaraldehyde as cross-linking agent. The effects of several parameters on particle size, drug encapsulation efficiency and drug release were investigated. Size and shape of the nanoparticles were examined by scanning electron microscopy. The release of MTX was monitored in vitro and the mechanism of release was studied. Particles with a mean diameter of 100-200 nm were produced, which were able to release MTX following a diffusion-controlled mechanism of release. It was observed that the initial amount of MTX used for sample loading did not have any effect on the pattern of release, while it affected the amount of drug entrapped into the nanoparticles and also both the release rate and the total amount of drug released.

Journal ArticleDOI
TL;DR: Tannins of different sources (grapes, wooden barrels, formulations used in wine making) were investigated, and their flow-through behavior was characterized, and significant differences in their affinity toward gelatin could be observed.
Abstract: The interaction of polyphenols (tannins) with proline-rich proteins (gelatin) has been studied using an automated flow injection system with Fourier transform infrared spectroscopic detection to gain insight into chemical aspects related to astringency. In the perception of astringency, a major taste property in red wines and other beverages such as beer, tea, or fruit juices, an interaction between proline-rich salivary proteins and tannins present in the sample takes place. To study this interaction, agarose beads carrying gelatin (a proline-rich protein) were placed in the IR flow cell in such a way that the beads were probed by the IR beam. Using an automated flow system, we injected samples in a carrier stream and flushed over the proteins in a highly reproducible manner. Simultaneously, any retardation due to tannin-protein interactions taking place inside the flow cell was monitored by infrared spectroscopy. Tannins of different sources (grapes, wooden barrels, formulations used in wine making) were investigated, and their flow-through behavior was characterized. Significant differences in their affinity toward gelatin could be observed. Furthermore, because of small but characteristic differences in the IR spectrum, it is possible to distinguish condensed from hydrolyzable tannins. Nonastringent substances such as alcohols, sugars, and acids did not show retention on gelatin. The selectivity of the flow-through sensor was also demonstrated on the example of red and white wine. In contrast to white wine, where no interaction could be observed, in red wine a major interaction of the red wine tannins was found.

Journal ArticleDOI
TL;DR: Gelatin/montmorillonite (MMT) hybrid nanocomposite was directly prepared with unmodified MMT and gelatin aqueous solution, and the properties of the composite were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and tensile tests as discussed by the authors.
Abstract: Gelatin/montmorillonite (MMT) hybrid nanocomposite was directly prepared with unmodified MMT and gelatin aqueous solution. Thermal and mechanical properties of the composite were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and tensile tests. The results indicated that an intercalated or partially exfoliated nanocomposite could be achieved, and the properties of the composite were significantly improved. A Tg peak of high temperature disappeared in the DSC curve of the composite, and the thermogravity and thermally decomposed rate decreased obviously. The tensile strength and Young's modulus were also improved notably, which varied with MMT content, as well as the pH of gelatin matrix. Meanwhile, SEM photographs showed a plasticizing trend of gelatin fracture surface due to intercalation with MMT. Furthermore, the wet mechanical behavior was initially studied. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1189–1194, 2002

Journal ArticleDOI
TL;DR: An in situ tissue-adhesive, drug-release technology based on a photoreactive gelatin, which allows in situ drug-incorporated gel formation on living tissues and sustained drug release directly on diseased tissues, effectively may be used to help inhibit tumor recurrence.
Abstract: We devised an in situ tissue-adhesive, drug-release technology based on a photoreactive gelatin, which allows in situ drug-incorporated gel formation on living tissues and sustained drug release directly on diseased tissues. Styrene-derivatized gelatins, synthesized by condensation reaction of gelatin with 4-vinylbenzoic acid, were photopolymerized in the presence of a water-soluble camphorquinone derivative as a photoinitiator upon visible-light irradiation to form swollen gels. Using albumin as a drug model, gelation characteristics and drug-release characteristics easily were manipulated by material variables, formulation variables, and operation variables. Tissue adhesivity of the gel was superior to that of fibrin glue. The biologic response, which was evaluated by intraperitoneal implantation in rats, showed that the gel was biodegraded and biosorbed, without cytotoxicity, within a few months after implantation. An in situ processable tissue-adhesive local drug release system effectively may be used to help inhibit tumor recurrence.

Journal ArticleDOI
TL;DR: The newly developed immobilization method is simple, yet effective and can be used for the immobilization of other enzymes.

Journal ArticleDOI
TL;DR: In this study, gelatin sponges prepared by using various cross-linkers such as glutaraldehyde, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDAC), and D-fructose demonstrated a higher cell viability for the samples cross-linked with low concentrations of GA than for those cross- linked with EDAC.
Abstract: Gelatin is a natural polymer used in pharmaceutical and medical applications, especially in the production of biocompatible and biodegradable wound dressings and drug delivery systems. Gelatin granules hydrate, swell and solubilize in water, and rapidly degrade in vivo. The durability of these materials could, however, be prolonged by cross-linking by aldehydes, carbodiimides, and aldose sugars, but the biocompatibility of collagenous biomaterials is profoundly influenced by the nature and extent of cross-linking. In this study, gelatin sponges were prepared by using various cross-linkers such as glutaraldehyde (GA), 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDAC), and D-fructose. The effects of the type and the amount of cross-linker on thermal and mechanical properties, stability, and cytotoxicity were investigated. The mechanical analysis data showed that an increase in the amount of GA in the sponge structures caused a slight increase in the modulus of elasticity but had almost no effect on the tensile strength. Increase in the EDAC concentration produced a maximum in the modulus of elasticity and tensile strength values. The stability of the sponges and the time required for complete degradation in aqueous media increased in parallel with the cross-linker content. In vitro studies carried out with fibroblast cells demonstrated a higher cell viability for the samples cross-linked with low concentrations of GA than for those cross-linked with EDAC.

Journal ArticleDOI
TL;DR: In vitro bioactivity of gelatin sponges and hydroxyapatite-enriched gelatinSponges was tested through evaluation of the variations in their composition and morphology after soaking in simulated body fluid for periods up to 21 days at 37 degrees C.
Abstract: In vitro bioactivity of gelatin sponges and hydroxyapatite-enriched gelatin sponges was tested through evaluation of the variations in their composition and morphology after soaking in simulated body fluid (1.5) for periods up to 21 days at 37°C. The presence of hydroxyapatite inside the sponges promotes the deposition of bonelike apatite crystals. The deposits are laid down as spherical aggregates, with mean diameters increasing from about 1–2 μm, after 4 days of soaking in simulated body fluid solution, up to about 3.5 μm in the samples soaked for 21 days. Simultaneously, the relative amount of inorganic phase increases up to about 56% wt, leading to a composite material with a composition quite close to that of bone tissue. The inorganic phase is a poor crystalline carbonated apatite similar to trabecular bone apatite. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 709–714, 2002

Journal ArticleDOI
TL;DR: The authors showed that the addition of poly-aspartate to the pore solution in either gelatin or poly-acrylamide hydrogel appears to overcompensate the physical properties of the organic matrix.
Abstract: Calcite particles are grown in a collagenous matrix using a counter-diffusion arrangement. Although microstructural analysis revealed a heterogeneous intergrowth of organic and inorganic phases within the particles, the composite growth is rather a consequence of local chemical environment that is not specific to the gelatin gel. However, using an artificial poly-acrylamide hydrogel results in a very different growth morphology. The addition of poly-aspartate to the pore solution in either gelatin or poly-acrylamide hydrogel appears to overcompensate the physical properties of the organic matrix, leading to morphologies independent of which hydrogel is used. Our results stress the importance of noncollageneous proteins within a physical growth environment.

Journal ArticleDOI
Zuwei Ma1, Changyou Gao1, Yihong Gong1, Jian Ji1, Jiacong Shen1 
TL;DR: Chondrocyte culture showed that the modified PLLA membranes had higher cell attachment, higher cell proliferation rate, and higher cell activity than the control PLLa membrane.
Abstract: With the use of a grafting-coating method, three kinds of natural macromolecules, that is, gelatin, collagen, or chitosan, were immobilized on poly-L-lactic acid (PLLA) membrane surfaces with the goal of improving of cellular interactions. Attenuated total reflectance infrared spectroscopy (ATR-IR), x-ray photoelectron spectroscopy (XPS) and surface morphology analysis using scanning electronic microscopy (SEM) confirmed that the natural macromolecule layers adhered tightly to the hydrophobic PLLA membrane surfaces. Chondrocyte culture showed that the modified PLLA membranes had higher cell attachment, higher cell proliferation rate, and higher cell activity than the control PLLA membrane. Moreover, the chondrocytes were more spread out on the modified PLLA membranes than on the control PLLA membranes.

Journal ArticleDOI
TL;DR: New types of hydrogels have been obtained starting from high bloom purified gelatin A by transglutaminase-catalyzed cross-linking, and main structural and conformational factors governing the physicochemical properties and the possible application are discussed.

Journal ArticleDOI
TL;DR: It is demonstrated that the marrow stromal cells survived the encapsulation procedure in uncrosslinked gelatin microparticles and also retained their proliferative potential and osteoblastic phenotype over a 28 day period, although at a slightly lower level than the nonencapsulated cells.

Journal ArticleDOI
TL;DR: Grafting of PHEMA, PMAA and protein on the surfaces was confirmed using ATR-IR and XPS and the surface wettability of the modified films was improved.

Journal ArticleDOI
TL;DR: It is suggested that water-holding by stabilizer and proteins, and in some cases steric hindrance induced by a stabilizer gel-like network, caused a reduction in the kinetics of the ice recrystallization phenomena and promoted mechanisms of melt-regrow instead of melt -diffuse-grow recrystalization, thus resulting in the preservation of theIce crystal size and in a small span of theice crystal size distribution.

Journal ArticleDOI
TL;DR: The results show that the interfacial tension can be related to the length of the tie-line or to the difference in the concentration of dextran (or gelatin) in the separated phases, and increases as either of these parameters increases.

Journal ArticleDOI
TL;DR: Most of the crosslinked gelatin-based materials, either via glutaraldehyde fixation or interpenetrating network formation, elicited stronger inflammatory responses than either of the starting materials, gelatin and polyethyleneglycol diacrylate.
Abstract: The in vivo host response to two gelatin-based hydrogel systems of varying crosslinking modalities and loaded with the anti-inflammatory agent dexamethasone sodium phosphate was investigated. Either gelatin was chemically crosslinked with glutaraldehyde, or polyethyleneglycol diacrylate was photopolymerized around gelatin to form interpenetrating networks. The subcutaneous cage implant system was utilized to determine differential leukocyte concentrations in the inflammatory exudate surrounding the materials as indices for biocompatibility and drug efficacy in vivo. Most of the crosslinked gelatin-based materials, either via glutaraldehyde fixation or interpenetrating network formation, elicited stronger inflammatory responses than either of the starting materials, gelatin and polyethyleneglycol diacrylate. In general, dexamethasone delayed and intensified the inflammatory response. The loss of material mass did not correlate directly with the degree of cellular inflammatory response, but increased with l...

Journal ArticleDOI
TL;DR: Polysaccharides, such as heparin, hyaluronan, and chitosan, were partially derivatized with a styryl or a methacryloyl group by condensation at a carboxyl or an amino group of the polysaccharide with 4-vinylbenzoic acid to produce water-swollen hydrogels only at relatively high concentrations.

Journal ArticleDOI
TL;DR: Gelatin (G) and xanthan gum (X) formed complexes either on bringing their blends to pH 2.3 or carrying out the electrode process in aqueous blends of X and G at pHs from 9 to 11.

Journal ArticleDOI
TL;DR: Betamethasone disodium phosphate (BTM)-loaded microspheres demonstrated good drug stability, high entrapped efficiency, and positive surface charge and the in vitro drug release from themicrospheres was related to gelatin content.

Journal ArticleDOI
TL;DR: Gelatin gels made from cod and megrim skins were formed using high pressure and subsequent cooling at 7°C during 16-18h as discussed by the authors during 16−18h.

Journal ArticleDOI
TL;DR: Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a glycoprotein that stimulates the production of granulocytes, macrophages, and white blood cells that is unstable in the medium, and rapidly degraded after day 5, and three stabilizing polymers were tested, polyethylene glycol, polyvinylpyrrolidone and gelatin.