Showing papers on "Glutaraldehyde published in 2002"
TL;DR: Poor biocompatibility and induction of apoptosis on collagen/poly(vinyl alcohol) films crosslinked by glutaraldehyde are attributed to glutaralde components on the surface of the films (not residual glutarhyde), whose effects can be quenched by glutamic acid, and prevented by insulin-like growth factor-1.
Abstract: Collagen has been investigated as a potential natural biomaterial, because of its occurrence in the extracellular matrix. Collagen requires crosslinking in this context, by reagents that are often cytotoxic. Glutaraldehyde is one such agent that is potentially cytotoxic. The aim of this study was to determine the cause of poor cell attachment and growth on collagen/poly(vinyl alcohol) bioartificial composite films, when crosslinked with glutaraldehyde. Dehydrothermal crosslinking was used as a comparison. Human osteoblasts were observed to undergo apoptosis on glutaraldehyde crosslinked films dependent on concentration of collagen present. Higher collagen content resulted in higher levels of apoptosis with poor cell attachment and spreading of remaining cells. Post-treatment of films with 8% L-glutamic acid prevented the apoptotic response of osteoblasts and allowed attachment and spreading. The addition of 100 nM insulin-like growth factor-1 to the culture medium also prevented apoptosis. Glutaraldehyde toxicity of crosslinked collagen has been demonstrated in this study, the mechanism of which is apoptosis. This study indicates that poor biocompatibility and induction of apoptosis on collagen/poly(vinyl alcohol) films crosslinked by glutaraldehyde are attributed to glutaraldehyde components on the surface of the films (not residual glutaraldehyde), whose effects can be quenched by glutamic acid, and prevented by insulin-like growth factor-1.
298 citations
TL;DR: Microspheres of chitosan crosslinked with three different crosslinking agents viz, glutaraldehyde, sulphuric acid and heat treatment have been prepared to encapsulate diclofenac sodium (DS) and are spherical and have smooth surfaces.
Abstract: Microspheres of chitosan crosslinked with three different crosslinking agents viz, glutaraldehyde, sulphuric acid and heat treatment have been prepared to encapsulate diclofenac sodium (DS). Chitosan microspheres are produced in a w/o emulsion followed by crosslinking in the water phase by one of the crosslinking methods. Encapsulation of DS has been carried out by soaking the already swollen crosslinked microspheres in a saturated solution of DS. Microspheres are further characterized by FTIR, x-RD and SEM. The in-vitro release studies are performed in 7.4 pH buffer solution. Microspheres produced are spherical and have smooth surfaces, with sizes ranging between 40-230 microm, as evidenced by SEM. The crosslinking of chitosan takes place at the free amino group in all the cases, as evidenced by FTIR. This leads to the formation of imine groups or ionic bonds. Polymer crystallinity increases after crosslinking, as determined by x-RD. The method adopted for drug loading into the microspheres is satisfactory, and up to 28-30% w/w loading is observed for the sulphuric acid-crosslinked microspheres, whereas 23-29 and 15-23% of loadings are obtained for the glutaraldehyde (GA)- and heat-crosslinked microspheres, respectively. Among all the systems studied, the 32% GA crosslinked microspheres have shown the sloxvest release i.e. 41% at 420 min, and a fastest release of 81% at 500 min is shown by heat crosslinking for 3 h. Drug release from the matrices deviates slightly from the Fickian process.
194 citations
TL;DR: Using different derivatives, it has been possible to obtain both pure enantiomers from the ester or the product, and changes in the E values were obtained in the hydrolysis of methyl mandelate though here always there was a enantiopreference for the S isomer.
163 citations
TL;DR: In this article, a comparison of sorption isotherms and sorption kinetics of chitosan derivatives with those of glutaraldehyde cross-linked chitosa is made.
Abstract: Palladium is efficiently extracted from dilute acidic solutions using chitosan derivatives. Sorption performances are enhanced by modification of chitosan through the grafting of sulfur compounds (thiourea, rubeanic acid), which creates new chelating groups, on chitosan backbone using glutaraldehyde as a linker. A comparison of sorption isotherms and sorption kinetics of these two derivatives with those of glutaraldehyde cross-linked chitosan shows that the rubeanic acid derivative of chitosan is the more efficient for the uptake of palladium from dilute solutions. The chemical modification is suspected of bringing chelating functionalities to the ion exchange resin. Sorption capacity is not influenced by the particle size of rubeanic acid derivative of chitosan. Sorption isotherms are described by the Langmuir equation. Increasing the temperature of the solution has little effect on sorption performances. Sorption kinetics are not greatly influenced by the particle size of the sorbent.
161 citations
TL;DR: The newly developed immobilization method is simple, yet effective and can be used for the immobilization of other enzymes.
117 citations
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.
116 citations
TL;DR: In this paper, it was shown that the degree of cross-linking could be well described by the Freundlich equation and the amounts of sorption of solutes and the immobilization capacities of enzymes onto the swollen chitosan beads were significantly affected by the degrees of crosslinking.
104 citations
TL;DR: In this paper, a new hybrid material that adsorbs transition metal ions was prepared by immobilizing chitosan on the surface of nonporous glass beads, which were first reacted with γ-aminopropyltriethoxysilane (APES), then the resulting aminated beads were treated with glutaraldehyde at 25°C.
92 citations
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...
91 citations
TL;DR: In this paper, a native catalase preparation was formulated with different additives for storage stabilization and better performance at high temperature and pH for long-term storage at 30°C and neutral pH.
91 citations
TL;DR: Results demonstrated that terbutaline sulfate loaded microspheres can be used for passive lung targeting and the degree of uptake by the lungs was higher than that of the other organs.
TL;DR: The results showed that grafting chitosan via imine formation could achieve a higher surface density for amino groups and give higher antibacterial activity to those four pathogenic bacteria tested as discussed by the authors.
Abstract: Three polyesters—poly(ethylene terephthalate), poly(2-methyl-1,3-propylene terephthalate-co-ethylene terephthalate), and poly(1,4-cyclohexylene terephthalate-co-ethylene terephthalate)—were preirradiated with 60Co-γ-rays. Then, acrylic acid and N-vinylformamide were grafted to these irradiated fibers. Fibers grafted with N-vinylformamide were further hydrolyzed with acid so that the amide groups would convert into amino groups, and they were treated with glutaraldehyde so that aldehyde groups would be introduced. Chitosan or chitooligosaccharide was then grafted to these fibers via either esterification or imine formation. Four pathogenic bacteria—methicillin-resistant Staphylococcus aureus-1 (MRSA), Staphylococcus aureus-2, Escherichid coli, and Pseudomonas aeruginosa—were tested to determine the antibacterial activities of chitosan-grafted and chitooligosaccharide-grafted fibers. The results showed that grafting chitosan via imine formation could achieve a higher surface density for amino groups and give higher antibacterial activity to those four bacteria tested. The antibacterial activity for E. coli was the highest and that for MRSA was the lowest among the four bacteria tested. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2977–2983, 2002
TL;DR: Sulfide production recovered more rapidly after nitrite treatment than it did after glutaraldehyde treatment, and biocide efficacy was quantified by recording the time required for sulfide production to recover following an antimicrobial treatment.
Abstract: A continuous flow reactor system was developed to evaluate the efficacy of antimicrobial treatments against sulfate-reducing bacterial biofilms. An annular reactor operating at a nominal dilution rate of 0.5 h−1 was fed one-tenth strength Postgate C medium diluted in 1.5% NaCl and was inoculated with a mixed culture enriched from oilfield-produced water on the same medium. Thin biofilms developed in this reactor after 2 days of operation. The activity of these biofilms resulted in approximately 50 mg S l−1 of sulfide at steady state prior to biocide treatment. Biocide efficacy was quantified by recording the time required for sulfide production to recover following an antimicrobial treatment. In a control experiment in which pure water was applied, the time required to reach 10 mg S l−1 sulfide after the treatment was 1.7±1.2 h, whereas the time to reach this level of sulfide after a pulse dose of 500 mg l−1 glutaraldehyde was delayed to 61±11 h. Nitrite treatment suppressed sulfide production as long as the nitrite concentration remained above 15 mg N l−1. Sulfide production recovered more rapidly after nitrite treatment than it did after glutaraldehyde treatment.
TL;DR: An understanding of the range of reactivity of crosslinking molecules, and how this relates to their molecular structure, may help to understand how to harness the Maillard reaction during food processing.
TL;DR: In this article, polymeric beads of poly(vinyl alcohol)-grafted-acrylamide with sodium alginate have been prepared by crosslinking with glutaraldehyde.
Abstract: Interpenetrating network polymeric beads of poly(vinyl alcohol)-grafted-acrylamide with sodium alginate have been prepared by crosslinking with glutaraldehyde. Cypermethrin, a widely used pesticide, was loaded with 80% efficiency in these hydrogel beads. The beads were characterized by Fourier transform infrared spectroscopy to confirm the grafting. Scanning electron microscopy was used to know the morphology of the beads. Equilibrium swelling experiments indicated that swelling of the beads decreased with an increase in crosslinking. The in vitro release studies were performed under static conditions and the release data have been fitted to an empirical relation to estimate the transport parameters. The diffusion coefficients have been calculated for the transport of pesticide through the polymeric beads using the initial time approximation method. These values showed decrease with increasing crosslinking as well as increasing pesticide loading. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 552–560, 2002; DOI 10.1002/app.10306
TL;DR: In this paper, a GL-7-ACA acylase was covalently immobilized on silica gels modified with 3-aminopropyltriethoxysilane followed sequentially by treatment with glutaraldehyde.
Abstract: GL-7-ACA acylase was covalently immobilized on silica gels modified with 3-aminopropyltriethoxysilane followed sequentially by treatment with glutaraldehyde. The overall immobilization procedure has several steps such as pretreatment of silica gel, modification of carrier surface by silanization, crosslinking by glutaraldehyde and coupling of GL-7-ACA acylase on the silica gel. In this study, each step in the immobilization procedure was optimized individually to improve the efficiency of the overall immobilization procedure of GL-7-ACA acylase. The optimal conditions of each step were determined as follows; pretreatment by 35% hydrogen peroxide, silanization by 10% 3-APTES at pH 9.0 for 120 min, crosslinking by using glutaraldehyde modified under alkaline (pH 8.5) solution at 60 °C for 20 min and coupling in 1.0 M phosphate buffer (pH 8.0). Especially, the adverse effect of glutaraldehyde, which was observed in this study, was reduced by modification of glutaraldehyde. Through the modification of glutaraldehyde, activity of immobilized GL-7-ACA acylase was increased up to about 60% compared to that obtained by using untreated glutaraldehyde. The immobilized GL-7-ACA acylase was tested for long-term stability and it was found that about 70% activity was retained after using it 20 times.
TL;DR: W-doped MCM-41 has been reported as a novel heterogeneous catalyst for the selective oxidation of cyclopentene to prepare glutaraldehyde with environmentally benign aqueous hydrogen peroxide as discussed by the authors.
Abstract: W-doped MCM-41 (W-MCM-41) has been reported as a novel heterogeneous catalyst for the selective oxidation of cyclopentene to prepare glutaraldehyde with environmentally benign aqueous hydrogen peroxide. It is found that tungsten species could stably exist in the silica-based matrix of MCM-41 up to a Si/W molar ratio of 40 by means of X-ray diffraction, laser Raman spectroscopy, scanning electron microscopy, etc. Proper content of tungsten species, high specific surface area and large mean pore size of the W-MCM-41 account mainly for its high catalytic activity in comparison with other W-containing heterogeneous catalysts. Complete conversion of cyclopentene and very high yield of glutaraldehyde (∼72%) are obtained over the W-MCM-41 catalyst with an Si/W molar ratio of 40. Furthermore, almost no tungsten species are leached into the reaction solution, enabling the catalyst to be employed for many reaction cycles without obvious degeneration. The correlation of the catalytic behavior with the special structural characteristics of the W-MCM-41 catalyst is also discussed through various characterization methods.
TL;DR: The use of GTA in vapor phase as crosslinking agent of natural and artificial polymer blends is demonstrated to be an efficacious procedure that avoids the presence of toxic residuals into materials.
Abstract: Glutaraldehyde (GTA) solutions are commonly used to crosslink biomolecules and artificial polymers in order to reduce the degradation rate and to avoid the rapid dissolution in biological fluids The toxicity of these materials is often due to the presence of GTA residuals unremoved by washing procedures In this study membranes of PVA-hyaluronic acid and PVA-gellan with different composition have been obtained by solution casting technique and crosslinked by exposure to vapors of GTA in acid environment The harmful effects of GTA residuals released from the membranes have been evaluated by the cytotoxicity and cytocompatibility in vitro tests, based on the cell culture method The results showed that these materials have no toxic effects: they do not affect cell viability and proliferation, nor exert damages on mithocondrial and lysosomal functions The poor adhesion of cells seeded directly onto membranes is due to the surface properties of these materials which are completely refractory at cell adhesion and proliferation The use of GTA in vapor phase as crosslinking agent of natural and artificial polymer blends is demonstrated to be an efficacious procedure that avoids the presence of toxic residuals into materials
TL;DR: In this article, the authors used three different aldehyde fixatives at different temperatures and over different time points to obtain the maximal β-Galactosidase (β-Gal) activity.
Abstract: β-Galactosidase (β-Gal) staining is widely used to demonstrate specific gene expression during evaluation of gene targets in vivo. This technique is extremely sensitive to fixation. Optimal fixation conditions are necessary to obtain the maximal β-Gal activity. In this experiment, Carnoy's and three different aldehyde fixatives were used at different temperatures and over different time points. Kidneys from LacZ-stop-human alkaline phosphatase (ZA/P) double reporter mice were used to generate positive material for the experiment. The results show that glutaraldehyde combinative solution (LacZ) produced the most consistent and reliable results. Paraformaldehyde and formaldehyde were effective as fixatives only at 4C for a period of less than 4 hr, and Carnoy's solution destroyed β-Gal activity.
TL;DR: From SEM and FT-IR measurements, it was indicated that the self-organization in the HAp/collagen nanocompsites continuously occurred during the drying process together with the removal of water and the increase of the density.
Abstract: Hydroxyapatite(HAp)/collagen nanocomposites were prepared by a coprecipitation method controlling the degree of cross-linkage between collagen molecules using glutaraldehyde. The precipitates filtered were dried in a freeze drier or naturally dried in the air at 25 °C. The naturally dried cakes had open channels of 5–15 μm in diameters, which were three-dimensionally and regularly developed over the whole samples, and showed a pretty good mechanical strength. The channels that were formed at spaces among the HAp/collagen particles, cross-linked one another, which had been filled up with water before its evaporation. The ordering state of the open channels depended on the degree of cross-linkage with glutaraldehyde; the optimal self-organized state was found when 30 molecules of glutaraldehyde were added per collagen molecule, though an excess amount of glutaraldehyde suppressed the appearance of the ordered state. From SEM and FT-IR measurements, it was indicated that the self-organization in the HAp/collagen nanocompsites continuously occurred during the drying process together with the removal of water and the increase of the density.
TL;DR: In this article, a thorough investigation on different controlled release systems were evaluated, and the required devices were constructed simultaneously and required experiments were performed The polymeric network and membranes of poly vinyl alcohol with cross-linking agent glutaraldehyde for preparation of hyrogel system was effected Paraqua, a type of herbicide was introduced as solute in the system Glutaraldehyde was utilized as cross-link agent at different concentration Increase in the concentration of the cross-linked agent will cause a decrease in the extent of release out of the system.
Abstract: A thorough investigation on different controlled release systems were evaluated The required devices were constructed simultaneously and the required experiments were performed The polymeric network and membranes of poly vinyl alcohol with cross-linking agent glutaraldehyde for preparation of hyrogel system was effected Paraquat, a type of herbicide was introduced as solute in the system Glutaraldehyde was utilized as cross-linking agent at different concentration Increase in the concentration of the cross-linking agent will cause a decrease in the extent of release out of the system The effect of temperature on hydrogel adsorption demonstrates a higher adsorption at lower temperature
TL;DR: Several covalent immobilization methods, which have been routinely used with proteins and antibodies, were studied for their ability to immobilize genetically engineered Escherichia coli cells to glass beads, and glutaraldehyde is a universal and convenient cross-linker, but there are some concerns with its effects on the cells and proteins.
TL;DR: The goal of this work is to alter the properties of glutaraldehyde modified porcine heart valves in such a way that vital endothelial cells can grow on the implant surfaces with a layer of hydrophilic polymers.
TL;DR: Both methods of gelatin-GA cross-linking provided a hydrophilic surface on silicone for endothelial cell adhesion and growth in vitro, indicating that these advantages are counterbalanced by strong hydrophobicity.
Abstract: Silicone is a biomaterial that is widely used in many areas because of its high optical clarity, its durability, and the ease with which it can be cast. However, these advantages are counterbalanced by strong hydrophobicity. Gelatin cross-linking has been used as a hydrophilic coating on many biomaterials but not on silicone rubber. In this study, two gelatin glutaraldehyde (GA) cross-linking methods were used to coat a hydrophilic membrane on silicone rubber. In method I, gelatin and GA were mixed in three different proportions (64:1, 128:1, and 256:1) before coating. In method II, a newly formed 5% gelatin membrane was cross-linked with a 2.5% GA solution. All coatings were hydrophilic, as determined from the measurement of contact angle for a drop of water on the surface. Bovine coronary arterial endothelial cells were shown to grow well on the surface modified by method II at 72 h. In method I, the cells grew well for gelatin-GA proportions of 64:1 and 128:1 at 72 h. No cell attachment on untreated silicone rubber was observed by the third d of seeding. The results indicated that both methods of gelatin-GA cross-linking provided a hydrophilic surface on silicone for endothelial cell adhesion and growth in vitro.
TL;DR: Chitosan-graft-poly(vinyl acetate) copolymers were prepared by a graft copolymerization with a redox initiator, cerium ammonium nitrate as discussed by the authors.
Abstract: Chitosan-graft-poly(vinyl acetate) copolymers were prepared by a graft copolymerization with a redox initiator, cerium ammonium nitrate. Chitosan molecules not only participated in the reaction, but also served as a role of surfactant. As a result, a stable dispersion solution was observed during the reaction. After drying, particulate membranes were formed because of the rigid chitosan chains at particles’ surface. When the membranes were soaked in the water, the hydrophilic chitosan absorbed a great amount of water, but not the hydrophobic poly(vinyl acetate) chains mainly constituted in the core of particles. A two-stage behavior was observed during the adsorption of copper ion in the copolymer membrane. The first stage was governed by both the diffusion and reaction; whereas only diffusion dominated the second stage. The diffusion rate increased with an increase in the amount of chitosan. In order to increase its mechanical strength and acid resistance, the copolymer membrane was cross-linked with a glutaraldehyde. However, the specific adsorption quantity of copper ion decreased as the extent of cross-linking was increased.
TL;DR: Reuterin is an effective agent in the sterilization and fixation of biological tissues and an effective crosslinking agent for biological tissue fixation, and the results obtained showed that reuter in is significantly less cytotoxic than glutaraldehyde.
Abstract: Bioprostheses derived from biological tissues have to be fixed and subsequently sterilized before they can be implanted in humans. Currently available crosslinking agents and sterilants used in the fixation or sterilization of biological tissues such as glutaraldehyde and formaldehyde are all highly cytotoxic, which may impair the biocompatibility of bioprostheses. Therefore, it is desirable to provide an agent suitable for use in biomedical applications that is of low cytotoxicity and may form sterile and biocompatible crosslinked products. To achieve this goal, a natural compound (reuterin), produced by Lactobacillus reuteri in the presence of glycerol, was used by our group. It is known that reuterin has antibacterial, antimycotic, and antiprotozoal activities. Additionally, as in the case with formaldehyde, reuterin may react with the free amino groups in biological tissues by using its aldehyde functional group. Therefore, it was speculated that reuterin could be used as a crosslinking agent and a sterilant for biological tissues in the same way as glutaraldehyde and formaldehyde. In the study, the production of reuterin, produced by Lactobacillus reuteri under control conditions, was reported. Preparative chromatography was used to purify reuterin. Also, the minimal inhibitory concentration and minimal bactericidal concentration of reuterin and its antimicrobial activity on a contaminated tissue were investigated. In addition, the cytotoxicity of reuterin was evaluated. Glutaraldehyde, the most commonly used sterilant in the sterilization of biological tissues, was employed as a control. Furthermore, the feasibility of using reuterin as a crosslinking agent in fixing biological tissues was studied. Fresh and the glutaraldehyde-fixed tissues were used as controls. The results obtained in the minimal inhibitory concentration and minimal bactericidal concentration studies and in the sterilization study of a contaminated tissue indicated that the antimicrobial activity of reuterin is significantly superior to its glutaraldehyde counterpart. In addition, the results obtained in the 3-(4,5-dimethylthiazol-yl)-2,5-diphenyltetrazolium bromide assay showed that reuterin is significantly less cytotoxic than glutaraldehyde. Additionally, it was found that reuterin is an effective crosslinking agent for biological tissue fixation. The reuterin-fixed tissue had comparable free amino group content, denaturation temperature, and resistance against enzymatic degradation as the glutaraldehyde-fixed tissue. In conclusion, the results obtained in this study indicate that reuterin is an effective agent in the sterilization and fixation of biological tissues.
TL;DR: A biosensor based on pH-sensitive field-effect transistors (pH-FETs) as transducer, and immobilised enzyme tyrosinase as biorecognition element, which was used for the determination of phenolic compounds in water solutions.
TL;DR: SIS plays an important role for bone induction in SIS/PLA scaffolds for the application of tissue engineering area and many kinds of secreted, circulating, and extracellular matrix-bound growth factors from SIS to significantly affect critical processes of tissue development and differentiation are possible.
Abstract: In order to endow with new bioactive functionality from small intestine submucosa (SIS) powder as natural source to poly(L-lactide) (PLA) and poly(lactide-co-glycolide) (PLGA) synthetic biodegradable polymer, porous SIS/PLA and SIS/PLGA as natural/synthetic composite scaffolds were prepared by means of the solvent casting/salt leaching methods for the possibility of the application of tissue engineered bone and cartilage. A uniform distribution of good interconnected pores from the surface to core region was observed the pore size of 40≈500 μm independent with SIS amount using the solvent casting/salt leaching method. Porosities, specific pore areas as well as pore size distribution also were almost same. After the fabrication of SIS/PLA hybrid scaffolds, the wetting properties was greatly enhanced resulting in more uniform cell seeding and distribution. Five groups as PGA nonwoven mesh without glutaraldehyde (GA) treatment, PLA scaffold without or with GA treatment, and SIS/PLA (Code No. 3;1∶12 of salt content, 0.4∶1 of SIS content, and 144 μm of median pore size) without or with GA treatment were implanted into the back of nude mouse to observe the effect of SIS on the induction of cells proliferation by hematoxylin and eosin, and von Kossa staining for 8 weeks. It was observed that the effect of SIS/PLA scaffolds with GA treatment on bone induction are stronger than PLA scaffolds, that is to say, in the order of PLA/SIS scaffolds with GA treatment > PLA/SIS scaffolds without GA treatment > PGA nonwoven > PLA scaffolds only with GA treatment = PLA scaffolds only without GA treatment for the osteoinduction activity. The possible explanations are (1) many kinds of secreted, circulating, and extracellular matrix-bound growth factors from SIS to significantly affect critical processes of tissue development and differentiation, (2) the exposure of SIS to GA resulted in significantly calcification, and (3) peri-implant fibrosis due to covalent bonding between collagen molecule by crosslinking reaction. In conclusion, it seems that SIS plays an important role for bone induction in SIS/PLA scaffolds for the application of tissue engineering area.
TL;DR: Chitosanase was immobilized on chitin with glutaraldehyde by cross-linking reaction and the immobilized enzyme showed better temperature stability than the free enzyme and its operation and storage stability were good.
TL;DR: This paper describes the measurement of glutaraldehyde in a hospital environment using solid-phase microextraction, and demonstrates that the procedure of adsorption, thermal desorption and derivatization is robust and reproducible.