Showing papers on "Glutaraldehyde published in 2011"
TL;DR: In‐vitro release studies of these drugs were carried out in simulated gastric and intestinal fluids at 37°C and it was observed that the drug release rates were influenced by the cross‐linking density, particle size and initial drug loading in the microspheres.
Abstract: Chitosan microspheres having good spherical geometry and a smooth surface were prepared by the glutaraldehyde cross-linking of an aqueous acetic acid dispersion of chitosan in paraffin oil using dioctyl sulphosuccinate as the stabilizing agent. Microspheres having different degrees of swelling were made by varying the cross-linking density. Microspheres were prepared by incorporating theophylline, aspirin or griseofulvin. Drug incorporation efficiencies exceeding 80% could be achieved for these drugs. In-vitro release studies of these drugs were carried out in simulated gastric and intestinal fluids at 37 degrees C. It was observed that the drug release rates were influenced by the cross-linking density, particle size and initial drug loading in the microspheres.
326 citations
TL;DR: Based on the quantitative and qualitative assessments, the 2.5% glutaraldehyde was proposed as a promising fixation solution both for observing morphology of both bacterial cell and surface ultrastructures, while the methonal/acetone mixture was the worst fixation solution which may obtain unreliable results.
Abstract: Fixation ability of five common fixation solutions, including 2.5% glutaraldehyde, 10% formalin, 4% paraformaldehyde, methanol/acetone (1:1), and ethanol/acetic acid (3:1) were evaluated by using atomic force microscopy in the present study. Three model bacteria, i.e., Escherichia coli, Pseudomonas putida, and Bacillus subtilis were applied to observe the above fixation methods for the morphology preservation of bacterial cells and surface ultrastructures. All the fixation methods could effectively preserve cell morphology. However, for preserving bacterial surface ultrastructures, the methods applying aldehyde fixations performed much better than those using alcohols, since the alcohols could detach the surface filaments (i.e., flagella and pili) significantly. Based on the quantitative and qualitative assessments, the 2.5% glutaraldehyde was proposed as a promising fixation solution both for observing morphology of both bacterial cell and surface ultrastructures, while the methonal/acetone mixture was the worst fixation solution which may obtain unreliable results.
173 citations
TL;DR: The nanofibrous structure fabricated by an electrospinning technique was found to enhance cell adhesion and proliferation and is a cost-effective simulation of GN structures’ promising applications on scaffold preparation for tissue engineering.
Abstract: Gelatin nanofibers (GNs) prepared by electrospinning were cross-linked with glutaraldehyde vapor to improve their water-resistant ability. After cross-linking treatment, the form of the fibers expr...
149 citations
TL;DR: A novel glucose-responsive controlled release of insulin system is constructed through coating enzyme multilayers on mesoporous silica particles (MSPs) that act as a valve to control theRelease of insulin in response to the external glucose level.
127 citations
TL;DR: The CLEAs catalyzed esterification reactions in cyclohexane, affording higher conversions than with the free enzyme, especially when longer fatty acids and alcohols were used as substrates.
Abstract: Cross-linked enzyme aggregates (CLEA ® s) were prepared from Candida rugosa lipase (CrL) using glutaraldehyde as the cross-linker. The optimum conditions of the immobilization process were determined (precipitant: ethanol, crosslinker concentration: 25 mM, enzyme concentration: 50 mg/ml, crosslinking time: 45 min.). CLEAs were shown to have several advantages compared to the free enzyme. They were more stable at 50 °C and 60 °C and had good reusability; retaining 40% of their initial activity after 15 recycles in aqueous media and remaining constant at that level thereafter, suggesting some initial leaching in water. The CLEAs catalyzed esterification reactions in cyclohexane, affording higher conversions than with the free enzyme, especially when longer fatty acids and alcohols were used as substrates.
115 citations
TL;DR: Genipin can be used as an alternative crosslinking agent for pericardial tissue, considering given its physical, mechanical, biochemical characteristics and low cytotoxicity comparable to glutaraldehyde.
Abstract: Background: In cardiac surgery, especially in the reconstruction of vascular structures and intracardiac defects, glutaraldehyde has usually been used as the reagent for fixing porcine or bovine pericardial tissues. But the well-known problem of calcification or cytotoxicity of glutaraldehyde motivates the search for a replacement. The aim of this study is to investigate the physical, mechanical, and biochemical characteristics of bovine pericardial tissues fixed with genipin, which is known to be a less toxic and more natural fixing reagent. Materials and Methods: Bovine pericardial tissues were fixed with different concentrations and conditions of glutaraldehyde and genipin. To determine the physical, mechanical, and biochemical differences among different concentrations and conditions, we divided the tissue into 18 groups by concentration, the addition of organic solvents, and the timing of adding the organic solvents, and compared the characteristics of each group. Results: Tensile strength, physical activity, and thermal stability tests revealed that the tissues fixed with glutaraldehyde were better with regard to mechanical strength and biochemical durability. However, the difference was not significant statistically. Conclusion: Genipin can be used as an alternative crosslinking agent for pericardial tissue, considering given its physical, mechanical, biochemical characteristics and low cytotoxicity comparable to glutaraldehyde. However, further studies are needed on the immune reaction and the long term changes in genipin-fixed tissues in the human body.
112 citations
TL;DR: In this article, the effects of crosslinked blend films of N-(2-hydroxy)propyl-3-trimethylammonium chitosan chloride (HTCC) and poly(vinyl alcohol) (PVA) were studied and a possible mechanism of crosslinking was proposed based on the results.
109 citations
TL;DR: In this paper, a crosslinked PEI nanofibrous affinity membrane was used for removing heavy metal ions via wet-electrospinning from its aqueous solution with the aid of low loading fiber-forming agent poly(vinyl alcohol) (PVA).
95 citations
TL;DR: The immobilization of procerain B, a novel cysteine protease, on glutaraldehyde-activated chitosan beads through covalent attachment is reported and it showed nearly 50% activity until the 10th use.
Abstract: Proteases have several applications in the food industry. We report the immobilization of procerain B, a novel cysteine protease, on glutaraldehyde-activated chitosan beads through covalent attachment. Glutaraldehyde not only serves as a cross-linking agent but also links the procerain B on the surface of bead through primary amine group (either lysine side chain or N-terminal) by Schiff base linkage. Immobilized procerain B was characterized for optimum functional range and stability with respect to pH and temperature. The chitosan-immobilized procerain B has broad pH and thermal optima. The effects of substrate concentration and reusability of immobilized beads were also studied. It showed nearly 50% activity until the 10th use.
90 citations
TL;DR: It was observed that increase in the cross‐linking density of the microspheres reduced the drug release rate considerably, suggesting that the release profiles could be controlled by changing the cross-linkingdensity.
Abstract: A new technique for the preparation of cross-linked polyvinyl alcohol (PVA) microspheres containing various drugs is described. An aqueous solution of PVA containing various concentrations of glutaraldehyde was dispersed as droplets in liquid paraffin using a suitable stabilizing agent. Cross-linking of PVA droplets with glutaraldehyde was induced by an acid catalyst (HCl) which was produced by the addition of small quantities of benzoyl chloride into the dispersion medium. Microspheres containing drugs such as aspirin, griseofulvin and nicotinic acid were prepared by carrying out the cross-linking reaction in the presence of such drugs. The drug release studies were carried out in simulated gastric and intestinal fluids without enzymes at 37 degrees C. It was observed that increase in the cross-linking density of the microspheres reduced the drug release rate considerably, suggesting that the release profiles could be controlled by changing the cross-linking density. It was also observed that a higher rate of release was obtained from smaller beads.
81 citations
TL;DR: Zhang et al. as mentioned in this paper proposed a method to solve the problem of artificial neural networks in the field of natural science and applied it at Zhangzhou Normal University (ZNU) in China.
TL;DR: Findings prove the potential of non-mulberry silk sericin/poly (vinyl alcohol) hydrogel matrices to be used as biocompatible and biopolymeric material for tissue-engineering and biotechnological applications.
TL;DR: In this paper, a biodegradable film based on a mixture of gelatin and poly(vinyl alcohol) cross linked with Glutaraldehyde (GLU) is presented.
TL;DR: Immobilization effectively improved the stability of the enzyme in aqueous solution against various deactivating conditions such as pH, temperature, denaturants, inhibitors, and organic solvents.
TL;DR: In this paper, the dynamic water vapour sorption properties of Scots pine (Pinus sylvestris L.) wood samples were studied to investigate the modifying effects of glutaraldehyde.
Abstract: The dynamic water vapour sorption properties of Scots pine (Pinus sylvestris L.) wood samples were studied to investigate the modifying effects of glutaraldehyde. Pine sapwood was treated with solutions of glutaraldehyde and a catalyst (magnesium chloride) to obtain weight per cent gains of 0.5, 8.6, 15.5, and 21.0%, respectively. The sorption behaviour of untreated and treated wood was measured using a Dynamic Vapour Sorption apparatus. The results showed considerable reduction in equilibrium moisture content of wood and the corresponding equilibrium time at each target relative humidity (RH) due to glutaraldehyde treatment. The moisture adsorption and desorption rates of modified and unmodified wood were generally faster in the low RH range (up to approximate 20%) than in the high range. Modification primarily reduced the adsorption and desorption rates over the high RH range of 20–95%. Glutaraldehyde modification resulted in a reduction in sorption hysteresis due to the loss of elasticity of cell walls.
TL;DR: In this paper, a poly vinyl alcohol (PVOH) membrane was crosslinked with 2, 4 and 6 mass% of four different kinds of crosslinkers, i.e. glutaraldehyde (GLU), oxalic acid (OA), dimethylol urea (DMU) and tetra ethyl ortho silicate (TEOS), to produce four different types of crosslinked PVOH membranes termed here as PVGLU, PVOA, PVDMU and PVTEOS membrane, respectively.
TL;DR: The MTT test showed that the gelatin/chitosan hydrogel clearly presented adequate cell viability, non-toxicity, and suitable properties, which has broadened the number of choices of biomaterials to be potentially used in biomedical applications such as biomaterial, drug delivery vehicles and skin tissue engineering.
Abstract: Gelatin/chitosan hydrogels were prepared by using glutaraldehyde as crosslinker. The porous structure was confirmed by scanning electron microscope (SEM). Swelling ratios of the hydrogels with various ratio of gelatin to chitosan and crosslinker reagent dosage were studied in phosphate-buffered saline (PBS). In addition, in-vitro cytotoxicity was assessed via MTT assay with fibroblastic cell cultured in hydrogel extractions. It was found that by increasing glutaraldehyde dosage and chitosan content, the swelling ratio of the hydrogels decreased in buffer solutions. The MTT test showed that the gelatin/chitosan hydrogel clearly presented adequate cell viability, non-toxicity, and suitable properties. Therefore, these developed blends, based on gelatin and chitosan has broadened the number of choices of biomaterials to be potentially used in biomedical applications such as biomaterial, drug delivery vehicles and skin tissue engineering.
TL;DR: Starch/polyvinyl alcohol hydrogel films and boron complexes of these hydrogels were synthesized with or without using glutaraldehyde as a cross-linking agent and showed moderate antibacterial activity and antifungal activity against tested microorganisms, however, SF-BA had no antimicrobial activity against these microorganisms.
TL;DR: The present study describes preparation and characterization of a thermally stable and biodegradable biopolymer using collagen and a natural polymer, alginic acid (AA), which was characterized for, degree of cross-linking, mechanical strength, thermal stability, biocompatibility (toxicity) andBiodegradability.
TL;DR: Data obtained indicate that the natural milk protein casein could be used as a matrix for sustained release oral dosage forms and drug incorporation efficiency of around 80% could be achieved by the technique.
Abstract: — A controlled release dosage form of theophylline in the form of microspheres using the milk protein casein as the matrix is described. Glutaraldehyde cross-linking of an aqueous alkaline solution of the protein containing the drug, dispersed in a mixture of dichloromethane/hexane having ca. 1% of an aliphatic polyurethane as the suspension stabilizer, led to the formation of the drug-loaded microspheres. Drug incorporation efficiency of around 80% could be achieved by the technique. Release profiles of the drug were examined in simulated gastric and intestinal fluids at 37°C. It was observed that the release was diffusion-controlled and followed the Higuchi model. Release characteristics were influenced by the cross-linking density, particle size and the extent of loading. Data obtained indicate that the natural milk protein casein could be used as a matrix for sustained release oral dosage forms.
TL;DR: In this article, a pH-sensitive stearic acid-coated interpenetrating polymer network (IPN) blend microspheres of chitosan and gelatin were prepared by the emulsion cross-linking method using glutaraldehyde.
Abstract: Novel pH-sensitive stearic acid-coated interpenetrating polymer network (IPN) blend microspheres of chitosan and gelatin were prepared by the emulsion cross-linking method using glutaraldehyde for ...
TL;DR: The chitosan microspheres could be further developed as a potential biodegradable carrier for oral controlled delivery of famotidine to overcome the poor bioavailability and frequent dose administration of the drug.
Abstract: Purpose: To formulate biodegradable chitosan microspheres loaded with famotidine to overcome the poor bioavailability and frequent dose administration of the drug. Methods: Chitosan microspheres were prepared by simple emulsification technique based on glutaraldehyde crosslinking. Various process and formulation variables such as speed of emulsification, crosslinking time, drug/polymer ratio, volume of cross linking agent and volume of surfactant were optimized. The microspheres were characterized for entrapment efficiency, drug loading, in vitro drug release, surface morphology, as well as by particle size analysis, Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). Results: The microspheres showed a smooth surface with a narrow particle size distribution (105 – 219 µm) and an entrapment efficiency of up to 73 %. They exhibited controlled drug release characteristics with 85.6 % of the drug released over a period of 24 h with an initial burst release of 26.9 % in the first 2 h. Drug release followed Higuchi release kinetics. FTIR and DSC data indicate that there was no drug interaction between the drug and polymer used. Conclusion: The chitosan microspheres could be further developed as a potential biodegradable carrier for oral controlled delivery of famotidine.
TL;DR: Genipin-cross-linking was effective in maintaining collagen fiber integrity in aqueous and cell culture media environments for up to 7 days and it was shown that fiber swelling could be controlled by using different cross-l linking conditions.
Abstract: The fabrication of a fibrous collagen scaffold using electrospinning is desirable for tissue-engineering applications. Previously, electrospun collagen fibers were shown to be unstable in aqueous environments and, therefore, cross-linking is essential to stabilize these fibers. In this study genipin, a significantly less cytotoxic cross-linking agent compared to glutaraldehyde, was used to cross-link electrospun collagen fibers. The significance of this research lies in the use of four alcohol/water solvent systems to carry out the crosslinking reaction to maintain fibrous morphology during cross-linking. The four cross-linking conditions established were: (1) ethanol, 5% water and 3 days, (2) ethanol, 3% water and 5 days, (3) ethanol, 5% water and 5 days, and (4) isopropanol, 5% water and 5 days at a genipin concentration of 0.03 M. Results illustrated that genipin-cross-linking was effective in maintaining collagen fiber integrity in aqueous and cell culture media environments for up to 7 days. In addition, it was shown that fiber swelling could be controlled by using different cross-linking conditions. Swelling of cross-linked fibers immersed in Dulbecco's modified eagle medium for 7 days ranged from 0 to 59 ± 4%. The cross-linked fibers were analyzed using scanning electron microscopy, Fourier transform infrared spectroscopy and ninhydrin assay. Finally, studies using primary human fibroblasts indicated good cell adhesion to these scaffolds. Overall, our data suggest that these stabilized fibrous collagen scaffolds provide a promising environment for tissue-regeneration applications.
TL;DR: The in vitro release of lysozyme from both types of cross-linked GMs was successfully controlled when they were suspended in PF127 gel, thus suggesting the potential use of this new combined formulation as a drug-depot system.
TL;DR: This study provides an advantageous immobilization method of serum containing antiviral antibodies to develop electrochemical biosensors for preliminary screening of viruses in clinical samples from outbreaks.
TL;DR: Post-fixation treatment with glycine, high-concentration GA fixation in organic solvent and combined treatment of these all strongly prevented calcification of GA-fixed bovine pericardium in rat subcutaneous implantation model.
Abstract: Objective: Glutaraldehdye (GA)-fixed xenografts are widely used in cardiovascular surgery. The objective of this study was to evaluate the anticalcification effect of glycine treatment and high-concentration GA fixation in organic solvent on GA-fixed bovine pericardium, and to evaluate the possible synergistic effect of combined treatment. Methods: Bovine pericardial tissues were divided into four groups according to the methods of treatment. Group 1 consisted of tissues fixed with 0.5% GA (control), group 2 fixed with 0.5% GA and post-treated with glycine, group 3 fixed with 2% GA in organic solvent (65% ethanol + 5% octanol), and group 4 fixed with 2% GA in organic solvent and post-treated with glycine. The material characteristics of the treated tissues were assessed by amino acid analysis, thermal stability test, uniaxial mechanical test and light microscopy. The tissues were subcutaneously implanted into 4-week-old rats for 8 weeks, and the calcium contents of the explanted tissues were measured. Results: Differently treated tissues resulted in no significant alterations in material characteristics and morphology as assessed by amino acid analysis, thermal stability test, uniaxial mechanical test, and light microscopy. Median calcium contents of groups 1, 2, 3, and 4 were 80.5 m gm g 1 , 1.0 m gm g 1 , 0.5 m gm g 1 and 1.7 m gm g 1 , respectively. The calcium contents of groups 2, 3 and 4 were all significantly lower than that of group 1 (p < 0.05). Conclusions: Post-fixation treatment with glycine, high-concentration GA fixation in organic solvent and combined treatment of these all strongly prevented calcification of GA-fixed bovine pericardium in rat subcutaneous implantation model.
TL;DR: The strain E. faecalis was the most resistant to the disinfectant solutions, and among them, glutaraldehyde was more effective than 2 and 1% hypochlorite for disinfection for 5 min; in the 10-min period there were no differences between the disinfectants.
Abstract: doi: 10.1111/j.1741-2358.2010.00400.x Evaluation of the efficacy of chemical disinfectants for disinfection of heat-polymerised acrylic resin
Objective: This study evaluated the efficacy of disinfectants on the internal aspect of heat-polymerised acrylic resin contaminated with microbial strains.
Background: Dentures absorb oral fluids and become contaminated by different microorganisms.
Methods: Two hundred and fifty rectangular specimens were made of heat-polymerised acrylic resin, and then divided into five groups corresponding to the microbial strains (Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, S. mutans and Enterococcus faecalis). After contamination, the specimens were immersed in 1 and 2% sodium hypochlorite and 2% glutaraldehyde for periods of 5, 10 and 15 min. The specimens were placed into tubes containing different broths and incubated at 35°C and then visually analysed. Turbidity in the medium indicated microbial growth. The Fisher’s exact test was used in the analysis of the results.
Results: The strain E. faecalis was the most resistant to the disinfectant solutions, and among them, glutaraldehyde was more effective than 2 and 1% hypochlorite for disinfection for 5 min; in the 10-min period there were no differences between the disinfectants. In 15 min of immersion, 1% hypochlorite and glutaraldehyde were more effective than 2% hypochlorite.
Conclusions: Disinfection for 10 min with 1% hypochlorite and glutaraldehyde is effective in disinfecting the internal aspect of heat-polymerised acrylic resin.
TL;DR: Operational stabilities of CIG and CIG-6-AHA were investigated in batch and plug-flow type reactors and the highest total amount of decomposed hydrogen peroxide (TAD-H₂O₁) was determined as 219.5 μmol for CIG/AHA in plug- flow type reactor.
TL;DR: Biodegradable tri-component graft copolymers, chitosan-poly(ε-caprolactone)-poly(ethylene glycol) (CPP), were synthesized via a mild route and were endowed with self-luminescent properties after crosslinked with glutaraldehyde, finding that the crosslinking process shrunk the drug-loaded micelles.
Abstract: Biodegradable tri-component graft copolymers, chitosan-poly(e-caprolactone)-poly(ethylene glycol) (CPP), were synthesized via a mild route, using sodium dodecyl sulfate-chitosan complex (SCC) as a precursor. Both PCL and PEG could be conveniently conjugated to the hydroxyl sites of chitosan without the need of tedious chemical protection/deprotection processes, thereby leaving the amino groups of chitosan intact. The self-assembly and release behavior of the copolymer micelles were investigated. Paclitaxel and rutin were used as model drugs. Spherical micelles could be formed through self-assembly of CPP in aqueous media. The micelle diameter increased with PEGylation degree and ranged from 30 to 45 nm. The incorporation of drugs into the micelles significantly raised the micelle diameter and diversified the micelle morphologies. The micelles were further subjected to glutaraldehyde treatment to prolong the release of the incorporated drugs. It was found that the crosslinking process shrunk the drug-loaded micelles. In addition, the micelles were endowed with self-luminescent properties after crosslinked with glutaraldehyde. By increasing crosslinking density, the release duration of the model drugs could be prolonged.
TL;DR: The glutaraldehyde-modified microparticles prepared at optimized formulation conditions revealed colon specific in vitro and in vivo drug release, indicating the potential of the developed formulation as a colon-specific drug delivery system.
Abstract: The aim of this study was to develop a colon-specific microparticle formulation based on pectin. Resveratrol was used as a model drug due to its potential therapeutic efficacy on colitis and colon cancer. Microparticles were produced by cross-linking pectin molecules with zinc ions and with glutaraldehyde as hardening agent for pectins. Different microparticles were prepared by varying the formulation variables. Effect of these formulation variables were investigated on particle shape and size, moisture content and weight-loss during drying, encapsulation efficiency, swelling-erosion ratio, and drug release pattern of the formulated microparticles. Formulation conditions were optimized based on the in vitro drug release study. Morphology, Fourier transform infrared spectroscopy, stability, and in vivo pharmacokinetic study of the microparticles prepared at the optimized formulation conditions were performed. Microparticles were spherical with 94%. The glutaraldehyde-modified microparticles prepared at optimized formulation conditions revealed colon specific in vitro and in vivo drug release. Plasma appearance of drug was delayed for 4-5 h after their administration directly into stomach, but displayed comparable area under the curve to other controls in the experiment, indicating the potential of the developed formulation as a colon-specific drug delivery system.