OBJECTIVETo investigate the effect of epigallocatechin-3-gallate (EGCG) on biomodification of demineralized dentine substrate, in its permeability, hydrophobicity, and inhibition ability to collagen enzymatic degradation.

METHODSThe dentine substrates were treated with simulated pulpal pressure created by mixtures of 0.02%, 0.1% EGCG/bovine serum albumin (BSA) in acidic environment (pH4.4) for 48 h. A fluid-transport model was used to measure the fluid permeability through demineralized dentine substrate. Positive replicas of dentine substrate were fabricated before and after being subjected to acidic environment for scanning electron microscope (SEM) examination. The blank group contained no EGCG and the positive group were treated with Gluma desensitizer. Static contact angle measurements on demineralized dentin and 0.1% EGCG primed dentin were performed by contact angle analyzer. The priming time were 60 s, 120 s, 0.5 h, 1 h. Dentine specimens bonded with Adper single bond 2 were subjected to 100 mg/L collagenase and observed under SEM. Resin-bonded specimens (with 0.02%, 0.1%, 0.5% EGCG priming, or without EGCG priming) were created for micro-tensile bond strength evaluation (MTBS). Resin-bonded specimens after thermol cycling were created for MTBS evaluation.

RESULTSThe fluid permeability in the blank control group increased ([151.3±22.3]%), the fluid permeability in 0.1% EGCG/BSA group decreased ([23.7±6.3]%). Compared to the blank control group, the contact angle of 120 s, 0.5 h, 1 h groups increased by 31.0%, 53.5%, 57.8% in deep dentin and 37.4%, 59.3%, 62.4% in shallow dentin. The SEM examination showed that 0.1% and 0.5% EGCG priming for 120 s significantly increased dentin collagen's resistance to collagenase. The immediate MTBS of 0.1% and 0.5% EGCG groups were (29.4±4.8) and (19.8± 4.9) MPa. After thermol cycling, the MTBS of 0.1% and 0.5% EGCG groups were (19.9±5.1) and (15.3± 6.3) MPa.

CONCLUSIONSUnder acidic environment (pH4.4), the 0.1% EGCG can reduce dentine permeability under acidic environment. The 0.1% EGCG can increase hydrophobicity of dentin substrate, and strengthen dentin substrate's resistance to collagenase hydrolysis, thus increased the resin-dentin bonding durability.

Acid Etching, Dental ; Catechin ; analogs & derivatives ; pharmacology ; Collagen ; chemistry ; drug effects ; Collagenases ; pharmacology ; Composite Resins ; Dental Bonding ; Dental Cements ; Dental Pulp ; Dentin ; chemistry ; drug effects ; Dentin Permeability ; drug effects ; Dentin-Bonding Agents ; Glutaral ; pharmacology ; Hydrogen-Ion Concentration ; Hydrolysis ; Methacrylates ; pharmacology ; Microscopy, Electron, Scanning ; Pressure ; Resin Cements ; Serum Albumin, Bovine ; pharmacology ; Tensile Strength ; Time Factors

Nano magnetic microspheres prepared by chitosan and poly acylic acid were applied to purifying superoxide dismutase from blood erythrocyte. Chitosan-polyacyilc acid graft copolymer was synthesized by free radical graft copolymerization with potassium persulfate as inititator. To prepare Fe3O4 magnetic fluids with chemical coprecipitation, chitosan-polyacylic nano magnetic microspheres were prepared with glutaraldehyde as crosslinking agent. Structure of nano magnetic microspheres was detected by FT-IR spectrometer. Particle size and morphology were characterized by JEM-4000EX technology. Chitosan-polyacylic nanometer microspheres have good paticle cize distribution, magnetic responsiveness and protein adsoption. Activity, product yield and activity recovery of SOD after purification reached 6 727 U/mg, 21.1%, and 85.7% respectively. Purification of blood superoxide dismutase by chistosan-polyacylic acid microspheres has its renewable and feasible nature.
Chitosan ; chemistry ; Erythrocytes ; enzymology ; Glutaral ; chemistry ; Magnetics ; Microspheres ; Polymers ; Spectroscopy, Fourier Transform Infrared ; Superoxide Dismutase ; isolation & purification

Five influencing factors of the polymerization process of glutaraldehyde with hemoglobin were studied in cluding the approach of feeding glutaraldehyde, hemoglobin concentration, the molar ratio of glutaraldehyde and hemoglobin, reaction time and temperature, in order to reduce the average molecular weight and to improve the effective polymerization ratio. The results showed that the optimal process reduced the average molecular weight of hemoglobin based oxygen carriers (HBOCs) from (350.20 +/- 35.45)kD to (158.60 +/- 8.70)kD and improved the effective polymerization ratio from 53.27% +/- 4.95% to 69.50% +/- 3.70%. When the experiments expanded 30 folds, the results of the effective polymerization ratio and the average molecular weight mentioned above could be achieved.
Female ; Glutaral ; chemistry ; Hemoglobins ; chemistry ; Humans ; Molecular Weight ; Oxygen ; chemistry ; Placenta ; Polymerization ; Pregnancy

OBJECTIVETo investigate the influence of cross-linking agents genipin and glutaraldehyde on the composite bio-sponge.

METHODSThe composite bio-sponge was prepared with the technology of lyophilization. The degree of cross linking was determined using absorptiometry of trinitrobenzenesulfonic acid; the cytotoxicity was tested by MTT assay; the degradation rate in vitro was valuated by lysozyme degradation.

RESULTS(1) The degree of cross linking of composite bio-sponge crosslinked using genipin and glutaraldehyde increased with the crosslinking time, and reached 26.43% and 54.63% respectively after crosslinking 3 d. (2) The water absorption rate of composite bio-sponge crosslinked using genipin was better than that of crosslinked using glutaraldehyde. (3) In the initial stage of cells incubation, all extracts of composite bio-sponges crosslinked using genipin and glutaraldehyde inhibited the growth of the cells, and the inhibition decreased with the incubation time; but the cytotoxicity of composite bio-sponge crosslinked using glutaraldehyde was higher than that of crosslinked using genipin. (4) After soaking in saline for 4 weeks, the degradation rate of composite bio-sponge crosslinked using genipin or glutaraldehyde was 32.1%, 28.4%, respectively; however, after soaking in saline containing lysozyme for 40 h, the degradation rate of composite bio-sponge was 36.7%, 31.2%, respectively.

CONCLUSIONCompared with the composite bio-sponge crosslinked using glutaraldehyde, the degree of cross linking and the cytotoxicity of the composite bio-sponge crosslinked using genipin decreased; however, the water absorption rate and the degradation rate increased.

Biocompatible Materials ; Cross-Linking Reagents ; chemistry ; Glutaral ; chemistry ; Iridoids ; chemistry ; Materials Testing

Purified hemoglobin was modified with pyridoxal 5-phosphate(PLP) and polymerized with glutaric dialdehyde(GDA) to get the products. By comparison of the physical, chemical and biological properties of different procedures for modification before and after polymerization, there is no significant difference in molecular distribution, methemoglobin(MetHb) concentration, oxygen carrier capacity, P50 and spectra. Furthermore, the procedure of modification after polymerization can save PLP greatly and decrease cost greatly. So the procedure of modification after polymerization is a better way in research and production. The addition of GDA could control the increasing of MetHb. By comparison on the physical, chemical and biological properties of different procedures, there is no significant difference in molecular distribution, MetHb concentration, oxygen carrier capacity and spectra between the procedure of adding GDA before PLP and that after PLP. But the P50 of adding GDA before PLP is much lower than that after PLP. So the procedure of adding GDA after PLP is a better way.
Blood Substitutes ; Chemical Phenomena ; Glutaral ; chemistry ; Hemoglobins ; chemistry ; Humans ; Methemoglobin ; chemistry ; Pyridoxal Phosphate ; analogs & derivatives ; chemistry

Concanavalin A (ConA) is immobilized on a pre-activated chitosan microspheres, and then oriented immobilization of urease is carried out based on the strong interaction between ConA and glycoprotein. The optimum immobilization conditions are as follows: glutaraldehyde concentration is 3.5%, ConA concentration 1 mg/mL, ConA pH 7.0 and urease concentration 0.4 mg/mL. For orientedly immobilized urease, the highest activity was allowed at pH 5.0-6.0 and temperature 77 degrees C, and the Michaelis constant (Km) was disclosed to be 11.76 mmol/L by Lineweaver-Burk plot. Compared with the free urease and the randomly immobilized urease, the optimum pH of the orientedly immobilized urease becomes smaller and the pH domain wider. Orientedly immobilized urease presents higher temperature resistance, higher affinity to the substrate, and higher stability of operation.
Chitosan ; chemistry ; Concanavalin A ; chemistry ; Enzymes, Immobilized ; Glutaral ; chemistry ; Glycoproteins ; chemistry ; Hydrogen-Ion Concentration ; Microspheres ; Temperature ; Urease ; metabolism

OBJECTIVETo investigate the effects of preemptive freezing with different temperature and cross-linking methods on the ultrastructure of collagen membrane and its influence on human fibroblast proliferation.

METHODSBovine collagen type I solution in concentration of 10 g/L was preliminarily frozen at -20 degrees C or - 80 degrees C for 12 hours, and lyophilized at -70 degrees C for 48 hours. The diameter of apertures in collagen membranes prepared with two different preliminary temperatures were observed by scanning electron microscope (SEM) and compared. The preliminary freezing temperature of - 80 degrees C was used for the following study. The apertures of collagen membrane performed with cross-linking glutaraldehyde and ultraviolet (UV) radiation cross-linking with glutaraldehyde (double cross - linking) after preliminary freezing were also compared. The proliferation of human fibroblasts inoculated in above cross-linking collagens were assessed by MTT assay, in terms of absorption value.

RESULTSThe mean diameter of apertures of collagen membrane pre-frozen at -20 degrees C was (172 +/- 374 microm, while that at -80 degrees C was (99 +/- 24) microm. The apertures of collagen membrane were reduced in size after glutaraldehyde cross-linking, while those of double cross-linking showed no change in size. There was obvious difference in absorption value of fibroblasts 8 days after seeding between above two cross-linking methods (1.534 +/- 0.013 for glutaraldehyde cross-linking, 3.778 +/- 0.010 for double cross-linking, P < 0.05).

CONCLUSIONThe collagen membrane after preliminary freezing at - 80 degrees C and double cross-linking with UV radiation and glutaraldehyde may be used as a dermal skeleton substitute.

Animals ; Cattle ; Cells, Cultured ; Coculture Techniques ; Collagen ; ultrastructure ; Cross-Linking Reagents ; chemistry ; Dermis ; cytology ; Fibroblasts ; cytology ; drug effects ; radiation effects ; Freezing ; Glutaral ; chemistry ; Humans ; Skin, Artificial ; Tissue Scaffolds ; Ultraviolet Rays

With sodium alginate as a carrier and glutaraldehyde as the crosslinking agent, an improved immobilization method of beta-glucosidase for production of soybean genistein was developed. As compared with entrapment or entrapment-crosslinkage, crosslinkage-entrapment that beta-glucosidase was treated with glutaraldehyde and then entrapped in sodium alginate remained high loading efficiency and activity recovery, Effects of bead sizes, concentrations of alginate and glutaraldehyde as well, on the loading efficiency and activity recovery were assessed. When compared with the free enzyme, the optimum temperature, pH value and Km of the immobilized beta-glucosidase were respectively shifted from 50 degrees C to 40 degrees C, 4.5 to 4.0 and 2.57 microg/mL to 2.02 miocrog/mL. The stabilities of the immobilized beta-glucosidase were considerably better than that of the native enzyme. The immobilized beta-glucosidase was employed to genistein production, 84.94% of the activity and 56.04% of conversion were kept after consecutive use of 6 times.
Alginates ; chemistry ; Aspergillus niger ; enzymology ; genetics ; Enzyme Stability ; Enzymes, Immobilized ; metabolism ; Genistein ; chemical synthesis ; chemistry ; Glucuronic Acid ; chemistry ; Glutaral ; chemistry ; Hexuronic Acids ; chemistry ; Isoflavones ; chemistry ; Soybeans ; chemistry ; beta-Glucosidase ; chemistry ; metabolism

White-rot fungus manganese peroxidase (MnP) oxidizes a wide range of substrates, rendering it an interesting enzyme for potential applications. The stability of MnP can be improved by immobilization. With sodium alginate, gelatin, or chitosan as a carrier, and glutaraldehyde as the crosslinking agent, MnP was co-immobilized using the embed-crosslinked method and the adsorb-crosslinked method. The immobilization conditions and the partial properties of the three immobilized enzymes were investigated. When compared with the free enzyme, the optimum pH values and the temperatures of the three immobilized MnPs carried by alginate, gelatin, and chitosan were respectively shifted from 7.0 to 5.0, 5.0, 3.0 and from 35 degrees C to 75 degrees C , 55 degrees , 75 degrees C . The thermostabilities of the three immobilized MnPs were considerably better than that of the native enzyme. The chitosan-decreased by less than 5% even after repeated use for 6 - 9 times. The ability of decolorizing azo dyes in static and shaky situation by gelatin-immobilized MnP approached to the free enzyme, and there was no loss of enzyme activity during 2 repeated batch reactions.
Adsorption ; Alginates ; chemistry ; metabolism ; Biocatalysis ; drug effects ; Chitosan ; chemistry ; metabolism ; Dose-Response Relationship, Drug ; Enzymes, Immobilized ; chemistry ; metabolism ; Fungal Proteins ; chemistry ; metabolism ; Gelatin ; chemistry ; metabolism ; Glucuronic Acid ; chemistry ; metabolism ; Glutaral ; pharmacology ; Hexuronic Acids ; chemistry ; metabolism ; Hydrogen-Ion Concentration ; Kinetics ; Peroxidases ; chemistry ; metabolism ; Schizophyllum ; enzymology ; Substrate Specificity ; Temperature

Chitosan microsphere has been wildly researched in controlled release of protein and peptide drug because of its excellent mucoadhesive and permeation enhancing effect across the biological surfaces. The control of the size and size distribution of microspheres is necessary in order to improve reproducibility, bioavailability, and repeatable release behavior. In this work, uniform-sized chitosan microspheres containing insulin were prepared by a novel membrane emulsification technique combined with glutaraldehyde crosslinking method. In order to prepare uniform-sized chitosn microspheres, it is necessary to modify hydrophilic membrane into hydrophobicity. It is found that there exists a linear relationship between the size of chitosan microspheres and pore size of the membrane used, so it is easy to control the size of microspheres by using membranes with different pore size. In this study, the effect of different amount of crosslinker and crosslinking time on microspheres' morphology, encapsulation efficiency (EE) and release profile of drug in vitro were investigated. It is shown that the morphology of microspheres is more smooth and spherical, and the release rate is slower with the increase of amount of glutaraldehyde and prolongation of crosslinking time. When the molar ratio of amino group of chitosan to aldehyde group of glutaraldehyde is 1:0.7, and crosslinking time is 1 h, the highest EE was obtained (about 65%). Date obtained suggest that chitosan microspheres prepared by this new method would be a promising system for controlled release of protein drugs.
Biocompatible Materials ; chemistry ; Chitosan ; chemistry ; Cross-Linking Reagents ; Delayed-Action Preparations ; chemical synthesis ; Drug Carriers ; chemical synthesis ; Emulsions ; Glutaral ; chemistry ; Humans ; Insulin ; pharmacokinetics ; Microspheres ; Particle Size