Showing papers on "Glutaraldehyde published in 2013"
TL;DR: The vapor cross-linked PVA nanofibrous mat shows a high potential to be used for efficiently capturing and killing pathogenic bacteria and also generated an excess amount of unreacted aldehyde functional groups that could reduce silver salts into silver nanoparticles.
Abstract: Polyvinyl alcohol (PVA) nanofibrous mat can be easily prepared via electrospinning its aqueous solution. However, the obtained nanofibrous mat is instantaneously dissolved in water. Therefore, rendering the environmentally friendly nanofibrous mat water insoluble by cross-linking mechanism is of great interest. The electrospun PVA nanofibrous mat with an average fiber diameter of ca. 400 nm could be effectively cross-linked by glutaraldehyde vapor at room temperature. The cross-linking not only resulted in a water-insoluble nanofibrous mat but also generated an excess amount of unreacted aldehyde functional groups that could reduce silver salts into silver nanoparticles. The in situ formed silver nanoparticles along the fibrous surface showed excellent antimicrobial activity against Escherichia coli. The vapor cross-linked nanofibrous mat shows a high potential to be used for efficiently capturing and killing pathogenic bacteria.
228 citations
TL;DR: Results indicated that cross-linked chitosan-glutaraldehyde is promising to be developed as a new antibacterial drug.
Abstract: This present study deals with synthesis, characterization and antibacterial activity of cross-linked chitosan-glutaraldehyde. Results from this study indicated that cross-linked chitosan-glutaraldehyde markedly inhibited the growth of antibiotic-resistant Burkholderia cepacia complex regardless of bacterial species and incubation time while bacterial growth was unaffected by solid chitosan. Furthermore, high temperature treated cross-linked chitosan-glutaraldehyde showed strong antibacterial activity against the selected strain 0901 although the inhibitory effects varied with different temperatures. In addition, physical-chemical and structural characterization revealed that the cross-linking of chitosan with glutaraldehyde resulted in a rougher surface morphology, a characteristic Fourier transform infrared (FTIR) band at 1559 cm−1, a specific X-ray diffraction peak centered at 2θ = 15°, a lower contents of carbon, hydrogen and nitrogen, and a higher stability of glucose units compared to chitosan based on scanning electron microscopic observation, FTIR spectra, X-ray diffraction pattern, as well as elemental and thermo gravimetric analysis. Overall, this study indicated that cross-linked chitosan-glutaraldehyde is promising to be developed as a new antibacterial drug.
182 citations
TL;DR: In this article, the effects of crosslinker concentration on the pepsin enzyme activity have been studied using variation of relative viscosity of the system and the results showed that with increasing crosslinkers agent concentration activity activity of enzyme reduces considerably and so cross-linker molar ratio to amine functional groups.
Abstract: Chitosan was crosslinked with different amount of glutaraldehyde to prepare appropriate hydrogels to be used as drug delivery system. The swelling behavior of freeze-dried hydrogels in aqueous media at different temperature and pHs has been examined. The swelling, porosity and biocompatibility behavior of samples were investigated to check effects of polymer/polymer and polymer/drug interactions on these system characteristics. Obtained experimental results illustrates that with increasing crosslinking agent from 0.068 to 0.30, swelling of the prepared samples degrees from 1200% to 600% and pore diameters change from 100 to 500 µm. To investigate systems biocompatibility in gastric conditions, effects of crosslinker concentration on the pepsin enzyme activity have been studied using variation of relative viscosity of the system. Presented results also show that with increasing crosslinker agent concentration activity of enzyme reduces considerably and so crosslinker molar ratio to amine functional groups ...
154 citations
TL;DR: It was found that the incorporation of silica nanoparticles could further decrease the PVA crystallinity, enhance the fluorescent efficiency, and largely redshift the emission band, as compared with the neat GA-chitosan-PVA blend film.
123 citations
TL;DR: The presence of chitosan in the blend beads decreased the cumulative insulin release in gastric media and enhanced behavior of alginate/chitOSan beads in intestinal medium due to the crosslinking.
112 citations
TL;DR: The microspheres showed control release property without showing any incompatibility in IPN device, and can be used as a potential carrier for controlled oral delivery of highly water soluble drugs like BH.
106 citations
TL;DR: The entrapment efficiency of fluorescein-isothiocyanate (FITC)-dextran as model drug was determined to 50% with no substantial effect on particle size and 80% of the drug is only released after enzymatic digestion.
Abstract: An optimum nanoprecipitation technique for gelatin nanoparticles is established, based on aqueous gelatin solution and ethanolic solution containing stabilizer. Crosslinking with glutaraldehyde results in stable gelatine nanoparticles. Several factors such as the surfactant concentration, type of surfactant, type of nonsolvent and gelatin concentration are evaluated. Gelatin nanoparticles with 200–300 nm can be produced using 20–30 mg mL � 1 of gelatin and a minimum of 7% w/v stabilizer (Poloxamer 407 or 188). Furthermore, methanol and ethanol are good nonsolvents, whereas other nonsolvents such as acetone, isopropyl alcohol, and acetonitrile, result in phase separation and visible precipitates. The entrapment efficiency of fluorescein-isothiocyanate (FITC)-dextran as model drug was determined to 50% with no substantial effect on particle size. 80% of the drug is only released after enzymatic digestion.
90 citations
TL;DR: In this paper, a greener and eco-friendly method to leather tanning process has been developed in the present investigation, which is based on d-Lysine aldehyde complex.
90 citations
TL;DR: In this paper, a chitosan-bovine serum albumin (Chi-BSA) cryogel with incorporated multiwalled carbon nanotubes (MWCNTs), ferrocene (Fc), and glucose oxidase (GOD) was fabricated.
Abstract: A novel, excellently stable glucose biosensor was fabricated based on a chitosan-bovine serum albumin (Chi-BSA) cryogel with incorporated multiwalled carbon nanotubes (MWCNTs), ferrocene (Fc), and glucose oxidase (GOD). A porous Chi-BSA cryogel was prepared by freezing and thawing of the chitosan-albumin hydrogel, synthesized by crosslinking with glutaraldehyde. The electron transfer of the Chi-BSA cryogel was enhanced using MWCNTs mediated by the Fc trapped within the cryogel. The glucose response of this biosensor was amperometrically measured at an applied potential of 0.175 V versus Ag/AgCl in a flow injection system. The MWCNTs/Chi-BSA-Fc/GOD biosensor demonstrated high operational stability after more than 350 injections (RSD = 3.6%), with a wide linear range from 0.010 to 30 mM and a low Michaelis–Menten constant (1.5 mM). The fabricated biosensor response to glucose was not affected by dissolved oxygen and showed no response to the common interferences in blood samples such as, ascorbic acid and uric acid, in physiological levels. In comparison with the standard hexokinase-spectrophotometric method employed by the hospital, the glucose concentrations in blood plasma samples measured by the modified electrode were in good agreement ( P > 0.05). This chitosan based cryogel would be an excellent enzyme supporting material for other biosensor applications.
80 citations
TL;DR: Gelatin from cold water fish skin was electrospun, crosslinked and investigated as a substrate for the adhesion and proliferation of cells, showing that glutaraldehyde treated fish gelatin is the most suitable substrate, of the three studied, for fibroblast adhesion
80 citations
TL;DR: In this paper, a crosslinked kappa carrageenan hydrogel was obtained from the extraction of Kappaphycus alvarezii seaweed for 2 min and then cured at 110 o C for 25 min.
Abstract: Glutaraldehyde-crosslinked kappa carrageenan hydrogel was prepared using glutaraldehyde (GA) as the crosslinking agent. Kappa carrageenan film obtained from extraction of Kappaphycus alvarezii seaweed was immersed in GA solution (1-5 wt%) for 2 min and then cured at 110 o C for 25 min. The obtained crosslinked film was washed and soaked in the ethanol to remove the unreacted GA. The obtained film was air dried at room temperature to a constant weight. The infrared spectra, thermal analysis, and the value of swelling degree of obtained hydrogel showed that kappa carrageenan was able to be crosslinked using GA by film immersion and high temperature curing method without catalyst presence. GA concentration less than 0.027 g GA/g polymer was not able to crosslink hydroxyls group of carrageenan. The swelling degree in water media decreased up to 60% with increasing GA concentration from 3% to 5%. The kappa carrageenan hydrogel was found to be pH sensitive.
TL;DR: A model indicated that ethylenediamine and a secondary amine in the molecule were key components for the formation of emissive species and the mechanism enables us to control the generation and elimination of autofluorescence.
TL;DR: The films show improved water barrier performance after cross-linking and the use of trace concentrations of glutaraldehyde in chitosan/starch films allows for possible application in the biomedical field.
TL;DR: The present study provides a novel CRF comprising a pesticide which is light-sensitive or high temperature-sensitive, and a method for preparing the improved pesticide formulation so that the pesticide release rate and release period could be adjusted.
Abstract: Controlled release formulation (CRF) of pesticides is highly desirable for attaining the most effective utilization of the pesticide as well as reducing environmental pollution. Due to the selective permeation and protection properties of the semi-permeable membrane, pesticide microcapsules have been widely used. In this work, we developed a novel two-step method for synthesizing highly stable silica–glutaraldehyde–chitosan composite avermectin microcapsules. The silica shell was formed through the hydrolysis and polycondensation of tetraethyl orthosilicate (TEOS) at the oil droplet–water interface by using TEOS as the silica precursor and hexadecyl trimethyl ammonium chloride as a surfactant. Then the silica shell was modified with 3-aminopropyltriethoxysilane. Chitosan nanospheres were prepared by adjusting the pH value of the solution and then cross-linking with modified silica at the surface of the silica shell in the presence of glutaraldehyde to form double-shelled avermectin microcapsules. The results showed that the resulting microcapsules had a remarkable loading ability for avermectin (about 40% w/w) and can protect avermectin against photo- and thermal degradation effectively. Compared to single-shelled microcapsules, the double-shelled ones had better controlled release properties under all conditions. The present study provides a novel CRF comprising a pesticide which is light-sensitive or high temperature-sensitive, and a method for preparing the improved pesticide formulation so that the pesticide release rate and release period could be adjusted.
TL;DR: In this paper, a new approach using alternative non-toxic, non-volatile aldehydes as hardeners: glyoxal or glutaraldehyde was proposed.
TL;DR: Results provide evidence thatCrosslinking with glutaraldehyde is cytotoxic to macrophage-like cells, and that crossl linking with a zero-length crosslinker like EDC can be an acceptable alternative crosslinking treatment for biomaterials.
01 Apr 2013
TL;DR: The sorbent removal efficiencies for p-nitrophenol ranged between 7.1% and 49%, and the values for H2AsO4(2-) ranged between 31% to 93% for the low and high molecular weight copolymers.
Abstract: Chitosan–glutaraldehyde copolymer sorbents were synthesized by reacting variable weight ratios (low, medium, and high) of glutaraldehyde with fixed amounts of chitosan. Two commercially available chitosan polymers with low (L) and high (H) relative molecular weights were investigated. The chitosan–glutaraldehyde (Chi–Glu) copolymer sorbents are denoted as CPL-X or CPH-X where X denotes the incremental level (X = −1, −2, −3) of glutaraldehyde. The copolymers were characterized using FT-IR spectroscopy and TGA. The solid–solution sorption isotherms in alkaline aqueous solution for the copolymers were characterized using absorbance and emission based spectroscopic methods for p-nitrophenol (PNP) and the arsenate oxoanion HAsO 4 2 - species, respectively. The Sips isotherm model was utilized to obtain sorption parameters at pH 8.5 and 295 K (i.e. sorbent surface area, sorption capacity and removal efficiency) for each copolymer sorbent. The sorbent surface areas for the low molecular weight chitosan copolymers are listed in parentheses (m2 g−1), as follows: CPL-1 (124), CPL-2 (46.7) and CPL-3 (31.6). The high molecular weight chitosan copolymers are as follows: CPH-1 (79.8), CPH-2 (64.7) and CPH-3 (96.3). The removal efficiencies depend on the pH, temperature, and the relative amounts of sorbate and sorbent. The sorbent removal efficiencies for p-nitrophenol ranged between 7.1% and 49%, and the values for H 2 AsO 4 2 - ranged between 31% to 93% for the low and high molecular weight copolymers.
TL;DR: In this paper, an improved water-in-oil emulsion technique using corn oil as organic phase was used to obtain spherical and smooth surface microparticles with mean diameter of 16 μm.
Abstract: The features of microparticles, as size, surface structure, and morphology, depend, mainly, on the methodology used for their preparation. Emulsion polymerization techniques are undoubtedly among the most widespread. However, the use of toxic, volatile organic solvents represents a major disadvantage, namely, because of environmental issues. In this study, we prepared glutaraldehyde cross-linked chitosan–poly(vinyl alcohol) microparticles by an improved water-in-oil emulsion technique using corn oil as organic phase. The application of this polymeric blend as microparticle is scarcely investigated. As resulting of the procedure here presented, spherical and smooth surface microparticles were obtained, with mean diameter of 16 μm. The cross-linking reaction between the aldehyde and the amino or the hydroxyl groups formed either an imine (Schiff’s base) or an acetal bond, respectively, as analyzed by infrared spectroscopy. The microparticles here described did not present cytotoxic potential. Accordingly, this study can find promising and successful application in biotechnology.
TL;DR: In this paper, an α-amylase is immobilized, using glutaraldehyde, onto magnetite nanoparticles prepared using gum acacia as the steric stabilizer (GA-MN), for the first time.
Abstract: In this work, α-amylase is immobilized, using glutaraldehyde, onto magnetite nanoparticles prepared using gum acacia as the steric stabilizer (GA-MN), for the first time. The immobilization of amylase to GA-MN is very fast and the synthesis of GA-MN is very simple. The use of GA enables higher immobilization of α-amylase (60%), in contrast to the unmodified magnetite nanoparticles (∼20%). The optimum pH and temperature for maximum enzyme activity for the immobilized amylase are identified to be 7.0 and 40 °C, respectively, for the hydrolysis of starch. The kinetic studies confirm the Michaelis–Menten behavior and suggests overall enhancement in the performance of the immobilized enzyme with reference to the free enzyme. Similarly the thermal stability of the enzyme is found to increase after the immobilization. The GA-MN bound amylase has also been demonstrated to be capable of being reused for at least six cycles while retaining ∼70% of the initial activity. By using a magnetically active support, quick separation of amylase from reaction mixture is enabled. The catalytic rate of amylase is actually found to enhance by twofold after the immobilization, which is extremely advantageous in industry. At higher temperature, the immobilized enzyme exhibits higher enzyme activity than that of the free enzyme.
TL;DR: In this paper, an attempt to depolymerize industrial organosolv lignin and glutaraldehyde in presence of an anthraquinone acid catalyst (AQCOOH) was described.
TL;DR: Thermal degradation kinetics of the gelatin raw material and as-spun electrospun membranes showed that the electrospinning processing conditions do not influence polymer degradation, and it is shown that the Electrospinning process does not affect the formation of the helical structure of gelatin chains.
TL;DR: It is reported here that inactivation of cells by treatment with formaldehyde, glutaraldehyde, or a combination of the two leads to markedly improved capture selectivity when cells to be analyzed are inactivated in the same manner.
Abstract: Previous work showed that cell imprinting in a poly(dimethylsiloxane) film produced artificial receptors to cells by template-assisted rearrangement of functional groups on the surface of the polymer thin film which facilitated cell capture in the polymer surface indentations by size, shape, and, most importantly, chemical recognition. We report here that inactivation of cells by treatment with formaldehyde (4%), glutaraldehyde (2%), or a combination of the two leads to markedly improved capture selectivity (a factor of 3) when cells to be analyzed are inactivated in the same manner. The enhanced capture efficiency compared to living cells results from two factors: (1) rigidification of the cell surface through cross-linking of amine groups by the aldehyde; and (2) elimination of chemicals excreted from living cells which interfere with the fidelity of the cell-imprinting process. Moreover, cell inactivation has the advantage of removing biohazard risks associated with working with virulent bacteria. These results are demonstrated using different strains of Mycobacterium tuberculosis.
TL;DR: Scanning electron microscopy revealed that CLEAs prepared using linear dextran polyaldehyde presented a porous structure with low steric hindrance, and thus exhibited excellent activity toward macromolecular substrates, which was 16 times higher than that prepared using glutaraldehyde.
TL;DR: In this article, a modified chitosan flake with citric acid by cross-linking with glutaraldehyde was used to enhance its adsorption capacity for lead.
Abstract: BACKGROUND
Chitosan flake is a bio-adsorbent that has been studied for adsorption of lead. However, its adsorption capacity for lead was low. To enhance its adsorption capacity, chitosan flakes were modified with citric acid by crosslinking with glutaraldehyde to supplement the functional groups with high affinity for Pb(II) ions.
RESULTS
Modified chitosan flakes with citric were prepared with maximum capacity for Pb(II) of 101.7 mg g−1 at 303 K, pH 5, and 300 min contact time. The experimental data were used to fit kinetic and isotherm models. The results show that the adsorption of Pb(II) on modified chitosan flake followed a pseudo-second-order model, and the rate of adsorption was controlled by the mass transport mechanism and intraparticle diffusion. In an equilibrium study, it was found that the Langmuir and Freundlich isotherm models were appropriate to describe the adsorption process, indicating a chemisorption process of Pb(II) on the modified chitosan flake. The negative value of the free energy (ΔG) and the positive values of the enthalpy (ΔH) and entropy (ΔS) indicated an endothermic and spontaneous adsorption process of lead (II) on citric acid grafted chitosan flakes (C-Gch).
CONCLUSION
Chitosan flake modified with citric acid by crosslinking with glutaraldehyde remarkably enhanced the adsorption capacity for Pb(II) ions. This material could be used as an effective adsorbent for the removal of Pb(II) from wastewater and contaminated water sources. © 2012 Society of Chemical Industry
TL;DR: The enzyme activity of the immobilized β-galactosidase on Chitosan beads reached the maximum when the concentration of glutaraldehyde solution was 0.3%.
Abstract: The effect of glutaraldehyde solution concentration, cross-linking time, cross-linking pH and cross- linking temperature on the enzyme activity of the immobilized β-galactosidase on Chitosan beads were studied. The enzyme activity was measured after immobilized by detecting the absorbance value at 420 nm.The results were as follows: the immobilized enzyme activity reached the maximum when the concentration of glutaraldehyde solution was 0.3%.The immobilized enzyme had optimal cross-linking time of 3h, optimal cross-linking pH of 6.5, optimal cross-linking temperature of 25°C, under these conditions, the immobilized enzyme activity reached 101, 96, 90 U/g, respectively.
TL;DR: In this paper, a cross-linked candidate polymer with maximum fluid absorbance capacity was used as a device for controlled release of urea, which increased the water holding capacity of the soil.
Abstract: Enzyme lipase catalyzed graft copolymerization of acrylic acid onto gum tragacanth was carried out in an aqueous medium using glutaraldehyde as a cross-linker, one more step towards green chemistry. Various reaction variables such as time, amount of solvent, temperature, pH, lipase concentration, and monomer and cross-linker concentrations were optimized to achieve a cross-linked candidate polymer with maximum fluid absorbance capacity. The structure and morphology were confirmed by Fourier transform infrared spectroscopy and scanning electron microscopy. The synthesized hydrogel held a large amount of water and was used as a device for controlled release of urea. A 10 % (w/w) of swelled hydrogel was found to enhance the water-holding capacity of the soil. The synthesized device could increase the moisture content up to 52 % in sandy loam soil and 72 % in clay soil and was found to enhance the water-holding capability of the soil. Further, the candidate polymer was studied for the controlled release of urea under eco-friendly conditions and showed case-II type urea release. The initial diffusion coefficient was found to be higher than the later diffusion coefficient indicating a higher urea release rate during the early stage. Thus, the synthesized polymer is important from technological point of view.
TL;DR: Gel electrophoresis showed that glutaraldehyde induced strong collagen gelation, while RF/UVA generated milder collagen cross-linking, which enhanced resin-dentin bond possibly through enhancing the stiffness and maintaining the expanding collagen matrix in the hybrid layer.
TL;DR: Beta-amylase glutaraldehyde derivative was the preparation with best features, presenting improved temperature and pH stability and activity, and the possibility of reusing the amylase was also shown, when this immobilized enzyme was fully active for five cycles of use.
TL;DR: In this article, the effect of glutaraldehyde (GLA) as a crosslinking agent was studied in an effort to improve the properties of chitosan (CS) biocomposite films prepared via solvent casting.
Abstract: Corn cob (CC) was used as a filler in chitosan (CS) biopolymer films. The effect of glutaraldehyde (GLA) as a crosslinking agent was studied in an effort to improve the properties of CS/CC biocomposite films prepared via solvent casting. The tensile strength and elongation at break values decreased, but the modulus of elasticity increased with CC content. However, the tensile properties of CS/CC biocomposite films improved when modified with GLA. The Fourier transform infrared (FTIR) results indicated the presence of imine bonds (C=N) and ethylenic groups due to the cross-linking reaction between CS and GLA. The thermal stability of CS/CC biocomposite films reduced with increasing CC content. The modification of CS/CC with GLA enhanced the thermal stability of the biocomposite films. Moreover, the wettability and adhesion of the CC-CS system were enhanced by modification with GLA, as demonstrated by a morphological study. The crosslinking agent glutaraldehyde positively affected the tensile strength, modulus of elasticity, and thermal stability of the biocomposite films.
TL;DR: In this article, a composite membrane having chitosan (CH) as the active layer supported on poly(1,4-phenylene ether sulfone) (PPEES) membrane was synthesized in the current study.