Showing papers on "Glutaraldehyde published in 2017"
TL;DR: The results of a CCK-8 (Cell Counting Kit-8) assay showed that the hydrogel and its physical mixture solution were not cytotoxic to human corneal epithelial cells at a low concentration and it is possible to conclude that the Hydrogels have an excellent potential for application in ophthalmic drug delivery systems.
180 citations
TL;DR: In this article, a hydrogel composite was synthesized by copolymerization between bacterial cellulose and gelatin, which showed that the gelatin was uniform in size and shape.
171 citations
TL;DR: In this article, a semi-interpenetrating polymer network hydrogels with improved mechanical properties and remarkable sensitivity toward pH changes were prepared using chitosan reinforced with cellulose nanocrystals (CNCs).
Abstract: Semi-interpenetrating polymer network hydrogels with improved mechanical properties and remarkable sensitivity toward pH changes were prepared using chitosan reinforced with cellulose nanocrystals (CNCs). Glutaraldehyde was used as a crosslinker because of its high reactivity toward the amine groups of chitosan. In this study, rod-shaped CNCs that were approximately 200–300 nm in length and 40–50 nm in width were prepared from microcrystalline cellulose via sulfuric acid hydrolysis. CNC ratios of 0, 0.5, 1, 1.5, 2, and 2.5% were selected to study the effects of CNCs on the mechanical properties and swelling behavior of the chitosan hydrogel. The crosslinking reaction between chitosan and glutaraldehyde was confirmed by the presence of a –C=N stretching group at 1548 cm−1 in the Fourier transform infrared spectrum of chitosan hydrogel. The crosslinking degree of the chitosan hydrogel was 83.6%. The X-ray diffraction patterns confirmed that adding CNCs induced a combination of amorphous and crystalline regions in the hydrogel matrix. Mechanical tests showed that the maximum compression of the chitosan hydrogel increased from 25.9 ± 1 to 50.8 ± 3 kPa with increasing CNC content from 0 to 2.5%. CNC-chitosan hydrogels exhibited excellent pH sensitivity and producing the maximum swelling ratio under acidic condition (pH 4.01). On the basis of the results of this study, we assume that the improved mechanical properties and excellent pH sensitivity of the CNC-chitosan hydrogels will expand their application scopes in various fields, such as tissue engineering, pharmaceuticals, and drug delivery.
135 citations
TL;DR: The observations affirmed that solution chemistry needs to be addressed in laboratory investigations to further industrial application and competitiveness of alternate resins.
105 citations
TL;DR: In this paper, crosslinked hydrogel with glutaraldehyde (HyCG) was developed, characterized and applied for the adsorption of Food Blue 2 (FBL2) and Food Red 17 (FR17) from aqueous binary system.
90 citations
TL;DR: The kinetic, thermo-stability and dye-decolorizing characteristics of CTS-Lac/mediator system reflect its potential for use in industrial and environmental biotechnology.
Abstract: Laccase/mediator systems are promising bio-remediating agents as the rates of reactions can be considerably enhanced in the presence of low molecular weight mediators. A monomeric 64-kDa laccase produced by Trametes versicolor IBL-04 was effectively immobilized onto chitosan microspheres using glutaraldehyde as activating/cross-linking agent. Chitosan beads developed from 2.5% (w/v) chitosan concentration and activated by 1.5% (v/v) glutaraldehyde solution displayed best laccase immobilization efficiency. Scanning electron microscopy showed that beads with encapsulated laccase on the surface were spherical in shape having large surface area. The chitosan beads immobilized laccase (denoted as CTS-Lac) exhibited a broader active pH and temperature range and showed maximum activity at pH 6.0 and 60 °C. After immobilization, the affinity of the enzyme toward its substrate increased (Km decreased), leading to enhanced catalytic efficiency (Vmax increased). As compared to free laccase, the CTS-Lac showed significantly improved thermal and storage stability. The catalytic activity of the immobilized laccase was also demonstrated by the decolorization of five different textile reactive dyes. In the presence of 2,2′-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) as redox mediator, a maximum of 100% decolorization was achieved within the shortest time period of 4.0 h, indicating the effectiveness of CTS-Lac for the removal of textile dyes from an aqueous solution. It also retained 80.19% of its activity after ten continuous decolorization cycles for Sandal-fix Red C4BLN. The kinetic, thermo-stability and dye-decolorizing characteristics of CTS-Lac/mediator system reflect its potential for use in industrial and environmental biotechnology.
83 citations
TL;DR: Improvement of overall performance of immobilized xylanase in respect to free form is suggested and can be used to make a bioreactor for various applications such as poultry feed preparations.
66 citations
TL;DR: In general, PEI treatment was the most effective in increasing enzyme stability, while glutaraldehyde had a milder stabilization effect, and crowded enzyme preparations were intermolecular crosslinked using Glu plus PEI, but some molecules still remained non-crosslinked.
60 citations
TL;DR: In this article, resveratrol was applied to cellulose acetate polymeric membranes used as coating on a Mg-1Ca-0.6Zr alloy for improved osseointegration processes.
59 citations
TL;DR: A novel heterofunctional carrier of being strengthened anion exchange and weakened covalent binding to avoid activity loss and improve operational stability of the immobilized lipase showed markedly improved operational stability, better reusability and higher esters than BCL-GAMNP, where MNPs were only modified with (3-aminopropyl) triethoxysilane and glutaraldehyde.
Abstract: Biodiesel production using immobilized lipase as a biocatalyst is a promising process. The performance of immobilized lipase is mainly determined by supporting materials and immobilization method. To avoid the shortcomings of adsorption and covalent bonding methods, in this study, we developed a novel heterofunctional carrier of being strengthened anion exchange and weakened covalent binding to avoid activity loss and improve operational stability of the immobilized lipase. 2,3-epoxypropyltrimethylammonium chloride with epoxy and quaternary ammonium group and glutaraldehyde were grafted onto aminated magnetic nanoparticles (AMNPs) to generate a new matrix, named GEAMNP. Then Burkholderia cepacia lipase (BCL) was immobilized on GEAMNP via anion exchange and covalent bonding. The transesterification between soybean oil and methanol was used to test the activities. Activity recovery of the immobilized BCL was up to 147.4% and the corresponding transesterification activity was 1.5-fold than that of BCL powder. The immobilized lipase was further used for biodiesel production to confirm its feasibility. The fatty acid methyl esters conversion yield could reach 96.8% in the first 12 h. Furthermore, the immobilized lipase, BCL-GEAMNP showed markedly improved operational stability, better reusability and higher esters than BCL-GAMNP, where MNPs were only modified with (3-aminopropyl) triethoxysilane and glutaraldehyde.
55 citations
TL;DR: An efficient method was developed for preparing medium-density fiberboard (MDF) adhesives with high performance, using chitosan as the main component and glutaraldehyde as a crosslinking agent, and the results indicated that the optimum internal bonding strength, modulus of elasticity, and water resistance complied with the requirement of the Chinese national standard for MDF.
TL;DR: The immobilization of the enzyme β-galactosidase at pH 7 at low ionic strength on pre-activated glutaraldehyde supports seems to be the most adequate in terms of activity, stability and immobilization rate.
Abstract: The enzyme β-galactosidase from Aspergillus oryzae has been immobilized in aminated (MANAE)-agarose beads via glutaraldehyde chemistry using different strategies. The immobilization on MANAE-supports was first assayed at different pH values (this gave different stabilities to the immobilized enzymes) and further modified with glutaraldehyde. Dramatic drops in activity were found, even using 0.1% (v/v) glutaraldehyde. The use of a support with lower activation permitted to get a final activity of 30%, but stability was almost identical to that of the just adsorbed enzyme. Next, the immobilization on pre-activated glutaraldehyde beads was assayed at pH 5, 7 and 9. At pH 7, full, rapid immobilization and a high expressed enzyme activity were accomplished. At pH 9, some decrease in enzyme activity was observed. Direct covalent immobilization of the enzyme was very slow; even reducing the volume of enzyme/support ratio, the yield was not complete after 24 h. The stability of the biocatalyst using pre-activated supports was about 4–6 folds more stable than that of the enzyme immobilized via ion exchange at pH 5, with small differences among them. Thus, the immobilization of the enzyme at pH 7 at low ionic strength on pre-activated glutaraldehyde supports seems to be the most adequate in terms of activity, stability and immobilization rate.
Abstract: In the present study, an in-house extracted ligninolytic enzyme cocktail from Ganoderma lucidum IBL-05 was effectively immobilized on alginate-chitosan beads using glutaraldehyde. The firm quality stable alginate-chitosan beads developed using optimum condition of 3.0: 0.5% (w/v), alginate: chitosan ratio; 1.0% (v/v) glutaraldehyde concentration and 0.5 mg/mL of protein concentration registered the maximum immobilization yield. The functional characteristics and surface morphology of the control and ligninolytic enzyme conjugated alginate-chitosan beads were characterized using Fourier-transform infrared and scanning electron microscopy, respectively. Evidently, after enzymatic treatment, a significant reduction in turbidities up to 84.02%, 57.84%, 86.14%, and 82.13% was recorded for apple, grape, orange and pomegranate juice, respectively. The enzymes were subsequently used for the delignification of various agro-industrial materials. The immobilized consortium caused the marked reduction in lignin content of all the plant residues with a maximum delignification of 57.3% in sorghum stover after 15 h. In conclusion, the study suggests the potential of the immobilized ligninolytic enzyme, as a cost-effective industrially desirable green catalyst, for biotechnological at large and industrial in particular, especially for delignification, food, and beverage applications.
TL;DR: Strong cytotoxicity of QACs, and synergistic activity of binary, ternary and quintuple mixtures are demonstrated, suggesting a synergistic interaction.
TL;DR: In this article, a relatively stable and high-activity immobilized trypsin through EDC and glutaraldehyde cross-linking was developed, and characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction, and transmission electron microscopy.
TL;DR: Preparation of dual responsive interpenetrating polymer network hydrogel microbeads from sodium alginate and functionally modified guar gum and Zidovudine justified the grafting reaction, structure, morphology and polymer-drug interactions.
TL;DR: In this paper, a chitosan/polyacrylonitrile semi-IPN hydrogel system was developed and the potential of blend hydrogels (Gel1, Gel4, GEL7) as adsorbents for the adsorption of Rhodamine B dye was studied.
Abstract: In the present study, a chitosan/polyacrylonitrile semi-IPN hydrogel system was developed. To do so various blends of chitosan/polyacrylonitrile were prepared. The miscibility of the polymers, crosslinking of chitosan via glutaraldehyde vapors to produce semi-IPN and microstructures of the hydrogels were determined with DSC, FT-IR and FE-SEM, respectively. The DSC thermograms of hydrogels blends showed a single Tg (at 179–152 °C for Gel1–Gel4), which suggested good miscibility between the two polymers. For semi-IPN (Gel7) the Tg appeared at slightly lower temperature (128 °C), which suggested reduced intermolecular interactions between the two polymers due to the crosslinking of the chitosan. FT-IR showed no change in the characteristic bands positions of the two polymers for hydrogel blends(Gel1–Gel4) and a characteristic doublet at 1563 cm−1 and 1630 cm−1 (for the crosslinking of chitosan with glutaraldehyde) for semi-IPN hydrogel (Gel7). The FE-SEM micrographs showed homogenous (with no phase separation) surface and cross section morphologies for the blends hydrogels (Gel1–Gel4) and semi-IPN hydrogel (Gel7). The aqueous behaviors of the blend hydrogel (Gel1) and semi-IPNs (Gel5–Gel7) were investigated with the reported methods. The % degree of swelling was observed to decrease whereas stability increased as the crosslinking time was increased. The semi-IPN hydrogel (Gel7) showed improved stability and fair swelling. The potential of blend hydrogel (Gel1) and semi-IPNs hydrogel (Gel7) as adsorbents for the adsorption of Rhodamine B dye was studied. Rhodamine B dye showed significant adsorption affinity for semi-IPN hydrogel (Gel7). The data fitted best to pseudo-second-order kinetic and Langmuir isotherm. Intraparticle diffusion model confirmed that diffusion is not the only rate-limiting step, some degree of boundary layer control may be also operating.
TL;DR: The X-ray attenuation of prepared chitosan coated tungsten trioxide NPs are higher than Iohexol as the commercially available iodinated contrasting agent at the same concentrations.
TL;DR: In this paper, a cross-linked electrospun polyvinyl alcohol (PVA) was used for metal uptake in aqueous systems, and the metal organic framework was used to decorate the PVA membranes.
Abstract: Polyvinyl alcohol (PVA) is a water soluble polymer that requires further treatment to be stabilized before it can be used in aqueous environments. Electrospun PVA is cross-linked by incorporating cross-linking agents directly into the electrospinning solution followed by post-electrospinning thermal treatments to attain stability in aqueous environments. Previously published works on post-treatments include glutaraldehyde vapor exposure or soaking in organic solvents such as ethanol. However, these treatments incur lots of difficulties and hazards especially in scale production. In this study, with a view of imminent scale-up production required, fabricating electrospun cross-linked PVA is investigated without using catalysts, toxic vapor exposure, or solvent treatment. To produce cross-linked electrospun PVA membranes, citric acid, maleic acid, and polyacrylic acid are, respectively, added to PVA solution prior to electrospinning. Two potential applications are examined; the first is to use the membranes as produced for metal uptake in aqueous systems. The second application is for ammonia adsorption after decorating the membranes with a metal organic framework, copper benzene-1,3,5-tricarboxylate (HKUST-1).
Journal Article•
TL;DR: Kinetic studies demonstrated that the immobilized trypsin retained efficient biocatalytic activity and higher activity and conformational stability than Fe3O4@CM-CTS-EDC-TRY, which indicates that GA is effective for the immobilization oftrypsin on Fe3 omitting the need for EDC.
TL;DR: It is demonstrated that lactose-mediated crosslinking is able to produce ultra thin gelatin hydro-films with suitable properties for biomedical applications, such as wound healing, when compared to conventional crosslinkers such as glutaraldehyde or genipin.
TL;DR: N-P-CLEAs showed obvious improvement in thermal stability and pH stability than the free enzyme and could hold relatively high activity retention in nonpolar and hydrophilic solvents and without activity loss at 4°C for more than six months.
TL;DR: In this paper, the authors used the statistical Plackett-Burman design (PBD) to investigate the effects of 11 factors on the preparation of the treated agar-Car gel disks, and the immobilization of β-D-galactosidase (β-gal) onto these disks.
Abstract: κ-Carrageenan (Car) was mixed with agar in order to improve the treated gel’s ability to covalently immobilize enzymes. The treatment process of the produced agar-Car gel involved reacting with both polyethyleneimine and glutaraldehyde so as to provide the functional groups necessary for the covalent binding of enzymes. The positive effect imparted by the addition of Car to agar was confirmed through the statistical Plackett-Burman design (PBD). The PBD was employed to investigate the effects of 11 factors on the preparation of the treated agar-Car gel disks, and the immobilization of β-D-galactosidase (β-gal) onto these disks. The PBD provided recommendations on the levels at which 10 of the tested factors should be employed in the future as these factors were shown to be insignificant. On the other hand, the significant factor, the loading enzyme’s activity, was optimized in order to attain the maximum observed activity of immobilized β-gal which amounted to 166.2 U/g gel. It was also shown that the agar-Car immobilized β-gal maintained 97.7% of its initial observed activity during its fifteenth reusability cycle.
TL;DR: In this paper, the main product of anthracene oxidation was 9, 10-anthraquinone, which was less toxic than its precursor, and was confirmed by elemental analysis, thermogravimetry, and infrared spectroscopy.
Abstract: Anthracene bioconversion was achieved by immobilized enzyme technology. An oxidation yield of 0.7 mg/L of polycyclic aromatic hydrocarbons reached 60% following 24 hours of incubation with laccase from Trametes versicolor covalently immobilized on glutaraldehyde activated chitosan at the optimal pH of 5 in the presence of diammonium 2, 2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) as the radical mediator. High-performance liquid chromatography indicated that the main product of anthracene oxidation was 9, 10-anthraquinone which is less toxic than its precursor. Highly porous 3 mm diameter chitosan macrobeads were synthesized by precipitation in alkaline solution. Support activation with glutaraldehyde was confirmed by elemental analysis, thermogravimetry, and infrared spectroscopy. The bioreactor system was characterized for kinetic parameters obtaining a Michaelis Menten constant of 0.13 mM and a maximum rate of 0.0011 µmol/min/mg, thermal stability and reuse. The protein and glutaraldehyde...
TL;DR: In this article, the effects of different ratios of glutaraldehyde (0.25, 0.50, 1.0, and 2.0%) on the characteristics of the gel spheres were evaluated.
Abstract: Twelve different samples of gel spheres were prepared from the biopolymers chitosan, alginate, and gelatin via polyion complex formation in aqueous solution with crosslinking by glutaraldehyde. Dropwise addition of a chitosan/gelatin solution into a solution containing alginate and glutaraldehyde gave the gel spheres. The effects of different ratios of glutaraldehyde (0.25%, 0.50%, 1.0%, and 2.0%), and gelatin (2.5%, 5.0%, and 10.0%) on the characteristics of the gel spheres were evaluated. An increase in the concentration of the glutaraldehyde led to forming true spheres in rigid form. By scanning electron microscopy (SEM), the gel spheres showed fibrous network propagation along the gel membrane surface. Fourier transform infrared (FT-IR) spectroscopy confirmed the crosslinking of the amino groups by the glutaraldehyde and the presence of crosslinking bonds between the amino groups of chitosan and the carboxyl groups in the alginate molecule. Swelling studies showed that increasing the degree of...
TL;DR: The effectiveness of the glutaraldehyde vapour approach for crosslinking collagen and show that materials with defined, intermediate stability could be obtained, for example, to control resorption rates in vivo are shown.
Abstract: Glutaraldehyde is a well-recognised reagent for crosslinking and stabilising collagens and other protein-based materials, including gelatine. In some cases, however, the use of solutions can disrupt the structure of the material, for example, by causing rapid dispersion or distortions from surface interactions. An alternative approach that has been explored in a number of individual cases is the use of glutaraldehyde vapour. In this study, the effectiveness of a range of different glutaraldehyde concentrations in the reservoir providing vapour, from 5% to 25% (w/v), has been explored at incubation times from 5 h to 48 h at room temperature. These data show the effectiveness of the glutaraldehyde vapour approach for crosslinking collagen and show that materials with defined, intermediate stability could be obtained, for example, to control resorption rates in vivo.
TL;DR: 5-Fluorouracil was encapsulated to investigate its controlled release (CR) characteristics in acidic and alkaline buffer media, and the release data suggested a non-Fickian transport mechanism.
Abstract: Carboxymethyl chitosan (CMCS) was synthesized and blended with gelatin (GE) to prepare hydrogel microspheres by w/o emulsion cross-linking in the presence of glutaraldehyde (GA), which acted as a cross-linker. 5-Fluorouracil (5-FU) was encapsulated to investigate its controlled release (CR) characteristics in acidic (pH 1.2) and alkaline (pH 7.4) buffer media. The microspheres which formed were spherical in nature, with smooth surfaces, as judged by the scanning electron microscopy (SEM). Fourier transform infrared spectroscopy (FTIR) confirmed the carboxymethylation of CS and the chemical stability of 5-FU in the formulations. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) confirmed the physical state and molecular level dispersion of 5-FU. Equilibrium swelling of microspheres was performed in water, in order to understand the water uptake properties. The in vitro release of 5-FU was extended up to 12 h in pH 7.4 phosphate buffer, revealing an encapsulation efficiency of 72%. The effects of blend composition, the extent of cross-linking, and initial drug loading on the in vitro release properties, were investigated. When analyzed through empirical equations, the release data suggested a non-Fickian transport mechanism.
TL;DR: Degradation kinetics of five hydraulic fracturing compounds in the absence and presence of the biocide glutaraldehyde were investigated under a range of redox conditions using sediment-groundwater microcosms and flow-through columns to elucidate biodegradation inhibition.
Abstract: The rapid expansion of unconventional oil and gas development has raised concerns about the potential contamination of aquifers; however, the groundwater fate and transport of hydraulic fracturing fluid compounds and mixtures remains a significant data gap. Degradation kinetics of five hydraulic fracturing compounds (2-propanol, ethylene glycol, propargyl alcohol, 2-butoxyethanol, and 2-ethylhexanol) in the absence and presence of the biocide glutaraldehyde were investigated under a range of redox conditions using sediment-groundwater microcosms and flow-through columns. Microcosms were used to elucidate biodegradation inhibition at varying glutaraldehyde concentrations. In the absence of glutaraldehyde, half-lives ranged from 13 d to >93 d. Accurate mass spectrometry indicated that a trimer was the dominant aqueous-phase glutaraldehyde species. Microbial inhibition was observed at glutaraldehyde trimer concentrations as low as 5 mg L–1, which demonstrated that the trimer retained some biocidal activity. ...
TL;DR: The results showed that the mechanical properties and water resistance of ply wood prepared with soy-based adhesive with PFG was better than that of plywood with the same amount of phenol-formaldehyde (PF).
Abstract: To prepare a low-formaldehyde soy-based adhesive with good water resistance, phenol-formaldehyde modified with glutaraldehyde (PFG) with lower free phenol and free formaldehyde contents was used to cross-link the soy-based adhesive. The results showed that the mechanical properties and water resistance of plywood prepared with soy-based adhesive with PFG was better than that of plywood with the same amount of phenol-formaldehyde (PF). The reaction between phenol and glutaraldehyde was proved by 13C-NMR. Under the optimized preparation conditions for plywood, that is to say, press temperature 160 °C, press time 4 min and resin loading 320 g·m−2, type I plywood could be prepared with 9% PFG as a cross-linker of soy-based adhesive. The Differential Scanning Calorimetry (DSC) result confirmed the cross-linking reaction between soy-based adhesive and PFG or PF. The activation energy of soy-based adhesive with cross-linker PFG was higher than that with PF resin.
TL;DR: With the addition of glycerol as a plasticizer enhanced the extensibility of films as well as the hydrophilicity, resulting in higher water vapor permeability and tensile strength of films.
Abstract: Pullulan based films possess several advantages, including high transparency, low toxicity, good biodegradability, good mechanical properties, and low oxygen permeability, are preferable for food packaging. The application of pullulan films on food packaging, however, has inherent disadvantage of high water solubility. In this study, glutaraldehyde and glycerol were used as the cross-linking reagent and the plasticizer respectively to improve water resistance and physical properties of the pullulan films. Effects of cross-linking degree on physical properties, including water absorptions, swelling behaviors, water vapor permeability and tensile strengths of films were evaluated. FTIR results demonstrated that the pullulan films were successfully cross-linked by glutaraldehyde. The tensile strength of pullulan films could be enhanced significantly (P < 0.05) when glutaraldehyde was between 1% and 5% (w/w); nevertheless, the amount of glutaraldehyde above 20% (w/w) led to films brittleness. With the addition of glycerol as a plasticizer enhanced the extensibility of films as well as the hydrophilicity, resulting in higher water vapor permeability.