Biological Evolution ; Chitin ; chemistry ; metabolism ; Fungi ; classification ; genetics ; metabolism ; Phylogeny

Chitin short fiber reinforced polycaprolactone composite was prepared by melting blending method. The cytotoxicity and biocompatibility of pure polycaprolactone and of chitin short fiber reinforced polycaprolactone composite were investigated in order to provide useful scientific basis for clinical application. The biocompatibility of pure polycaprolactone and that of chitin short fiber reinforced polycaprolactone composite were evaluated by a series of tests, including cytotoxicity test in vitro, acute systemic toxicity test, hemolysis test, pyrogen test and sensitivity test. The results showed that the cytotoxicity scores of the two materials were grade 0 and the growth and proliferation of the cultured cells were not significantly inhibited by the two materials. There were no potential allergic materials in the composites and the maceration extract showed no hemolytic reaction, no acute systemic toxicity and no pyrogen reaction. We conclude that the composites have fine biocompatibility and are safe for clinical use in the reconstruction treatment for chest wall defect.
Biocompatible Materials ; chemistry ; Bone Substitutes ; chemistry ; Chitin ; chemistry ; Materials Testing ; Polyesters ; chemistry

We have investigated the degradation of pure Polycaprolactone (PurePCL) and chitin short fiber reinforced Polycaprolactone composite (SFRP) in vitro in order to provide useful scientific basis for clinical application. PurePCL, SFRP and DL-PLA were immersed in 0.9% NaCL solution for periods of 2, 4, 8, 12, 16 and 24 weeks. Then pH values in immersing solution, weight loss and mechanical properties of tested materials were measured and SEM was used to study the change of the materials in the process of degradation. It was shown that the initial strength of SFRP was much higher than that of PurePCL. In the process of degradation of SFRP, the pH values maintained weak acid or remianed neutral. The rate of weight loss of SFRP was faster than that of PurePCL, but slower than that of DL-PLA. The strength and modulus of SFRP did not change much in 24 weeks, compared with the initial ones. In conclusion, the composites have excellent properties and may be optimal for clinical use in reconstruction of chest wall defects as well as in internal fixation of bone fracture.
Biocompatible Materials ; chemistry ; Bone Substitutes ; chemistry ; Chitin ; chemistry ; Composite Resins ; chemistry ; Materials Testing ; Polyesters ; chemistry ; Prostheses and Implants

Chitosanases represent a class of glycoside hydrolases with high catalytic activity on chitosan but nearly no activity on chitin. Chitosanases can convert high molecular weight chitosan into functional chitooligosaccharides with low molecular weight. In recent years, remarkable progress has been made in the research on chitosanases. This review summarizes and discusses its biochemical properties, crystal structures, catalytic mechanisms, and protein engineering, highlighting the preparation of pure chitooligosaccharides by enzymatic hydrolysis. This review may advance the understandings on the mechanism of chitosanases and promote its industrial applications.
Chitosan/chemistry* ; Chitin ; Glycoside Hydrolases/genetics* ; Protein Engineering ; Oligosaccharides/chemistry* ; Hydrolysis

This paper reviewed application of chitin and its derivatives in pharmaceutical industry of traditional Chinese medicine in recent years. Chitin and its derivatives could be used as a clarificant, retaining active substances, stabiliting preparation, reducing the heavy metals of traditional Chinese medicine extraction. Because of their churacteristics in biodegradation, biocompatibility and its tendency to film easily, chitin and its derivatives was ideal assistant materials in traditional Chinese medicine. Its application was largely enhanced after chitosan was modified. The problems and prospects of the application of chitin and its derivatives were also discussed.
Adjuvants, Pharmaceutic ; Chitin ; chemistry ; Chitosan ; chemistry ; Drug Carriers ; Drugs, Chinese Herbal ; chemistry ; Humans ; Medicine, Chinese Traditional ; Pharmaceutical Preparations

OBJECTIVETo prepare microbubble, made of N-carboxymethyl chitosan, as ultrasound contrast agent and evaluate its characteristics and acoustic effects in vivo.

METHODSOil-Water-Oil multiple emulsion/solvent evaporation method was used to prepare the microbubble contrast agent. Both optical micrography and scanning electron micrography were performed to determine the bubble size and morphology. The acoustic effect of the N-carboxymethyl chitosan echo contrast agent was evaluated in vivo in rabbit. Liver echo images were recorded with ultrasound machine before and after intravenous bolus injecting 0.5 ml of the agent.

RESULTSThe novel N-carboxymethyl chitosan echo contrast agent was formulated as lyophilized product, with a mean diameter of 2-3 microm and a shell thickness of 250-300 nm. Its size is relatively uniform. The imaging effect was remarkably enhanced with the ultrasonic contrast agent when applied in rabbit livers.

CONCLUSIONIt is feasible to prepare excellent microbubble ultrasound contrast agent with N-carboxymethyl chitosan as membrane components.

Animals ; Chitin ; analogs & derivatives ; chemical synthesis ; chemistry ; Contrast Media ; Liver ; diagnostic imaging ; Microbubbles ; Rabbits ; Ultrasonics ; Ultrasonography

The biofilms formed by pathogenic microorganisms seriously threaten human health and significantly enhance drug resistance, which urgently call for developing drugs specifically targeting on biofilms. Chitooligosaccharides extracted from shrimp and crab shells are natural alkaline oligosaccharides with excellent antibacterial effects. Nevertheless, their inhibition efficacy on biofilms still needs to be improved. Spirulina (SP) is a microalga with negatively charged surface, and its spiral structure facilitates colonization in the depth of the biofilm. Therefore, the complex of Spirulina and chitooligosaccharides may play a synergistic role in killing pathogens in the depth of biofilm. This research first screened chitooligosaccharides with significant bactericidal effects. Subsequently, Spirulina@Chitooligosaccharides (SP@COS complex was prepared by combining chitooligosaccharides with Spirulina through electrostatic adsorption. The binding of the complex was characterized by zeta potential, z-average size, and fluorescence labeling. Ultraviolet-visible spectroscopy (UV-Vis) showed the encapsulation efficiency and the drug loading efficiency reached up to 90% and 16%, respectively. The prepared SP@COS2 exhibited a profound synergistic inhibition effect on bacterial and fungal biofilms, which was mainly achieved by destroying the cell structure of the biofilm. These results demonstrate the potential of Spirulina-chitooligosaccharides complex as a biofilm inhibitor and provide a new idea for addressing the harm of pathogenic microorganisms.
Humans ; Spirulina ; Anti-Bacterial Agents/chemistry* ; Chitosan/pharmacology* ; Biofilms ; Chitin/pharmacology*

Immunoglobulin Y (IgY) is an effective orally administered antibody used to protect against various intestinal pathogens, but which cannot tolerate the acidic gastric environment. In this study, IgY was microencapsulated by alginate (ALG) and coated with chitooligosaccharide (COS). A response surface methodology was used to optimize the formulation, and a simulated gastrointestinal (GI) digestion (SGID) system to evaluate the controlled release of microencapsulated IgY. The microcapsule formulation was optimized as an ALG concentration of 1.56% (15.6 g/L), COS level of 0.61% (6.1 g/L), and IgY/ALG ratio of 62.44% (mass ratio). The microcapsules prepared following this formulation had an encapsulation efficiency of 65.19%, a loading capacity of 33.75%, and an average particle size of 588.75 μm. Under this optimum formulation, the coating of COS provided a less porous and more continuous microstructure by filling the cracks on the surface, and thus the GI release rate of encapsulated IgY was significantly reduced. The release of encapsulated IgY during simulated gastric and intestinal digestion well fitted the zero-order and first-order kinetics functions, respectively. The microcapsule also allowed the IgY to retain 84.37% immune-activity after 4 h simulated GI digestion, significantly higher than that for unprotected IgY (5.33%). This approach could provide an efficient way to preserve IgY and improve its performance in the GI tract.
Alginic Acid/chemistry* ; Chitin/chemistry* ; Chitosan ; Delayed-Action Preparations ; Digestion ; Drug Compounding ; Drug Liberation ; Gastrointestinal Tract/metabolism* ; Immunoglobulins/metabolism* ; Oligosaccharides

Amphiphilic coupling-polymer of stearyl poly (ethylene oxide)-co-4, 4'-methylendiphenyl diisocyanate-co-stearyl poly(ethylene oxide), MSPEO, was specially designed as surface-modifying additives. The blends of MSPEO in both polyether urethane (PEU) and chitosan(Chi), as the coating materials for intravascular device were investigated. Two kinds of static clotting time tests, plasma recalcification time (PRT) and prothrombin time(PT), as well as the static platelet adhesion experiment were carried out. And the dynamic anti-coagulation experiment was performed with a closed-loop tubular system under a blood shear rate of 1,500 s-1. The results demonstrate that both blend coatings can improve the anti-coagulation of polyurethane greatly and will not lead to hemolysis, and that more platelets adhere to the surface modified by Chi-MSPEO blend coating as compared with those adhere to the surface modified by PEU-MSPEO blend coating. The surface modified by Chi-MSPEO has longer PRT, whereas the surface modified by PEU-MSPEO has longer PT.
Blood Coagulation Tests ; Chitin ; analogs & derivatives ; chemistry ; Chitosan ; Coated Materials, Biocompatible ; chemistry ; Ethylene Oxide ; chemistry ; Humans ; Materials Testing ; Platelet Adhesiveness ; Polymers ; chemistry ; Polyurethanes ; chemistry ; Prothrombin Time ; Surface Properties

Animals ; Cations ; chemistry ; Chitin ; administration & dosage ; analogs & derivatives ; chemistry ; Chitosan ; DNA ; administration & dosage ; Gene Transfer Techniques ; Genetic Therapy ; Liposomes ; administration & dosage ; chemistry ; Polylysine ; administration & dosage ; chemistry