| Chitosan is a kind of positively charged with a sugar base of naturalmacromolecular polysaccharide which is positively charged in its units.Typically chitosan are formed by deacetylation of chitin, which are extractedfrom crustacean shelll. Although the biological properties of chitosan improve alot compare to chitin’s properties, but chitosan can only be dissolved in weakacid solution, it also greatly limits its application. Thus, to improve theirbiological properties and physicochemical properties,we choose to graftmodification of chitosan to form chitosan derivatives. Common chitosanderivatives include: carboxylated chitosan, hydroxy chitosan, the sulfosalicylicchitosan, et al. They have different biological properties as their molecularstructure are not the same. Due to the decent characteristics of chitosan andits derivatives(good solubility, ability to form film, emulsifying properties,biocompatibility, biodegradability and non-toxic, etc).,they are widely used in allaspects of daily life and production.Biomedical materials are materials that used in diagnosis, treatment andreplacement of damaged human organs, or function as protection of theseinjured organs to enhance its functionality,.In general, excellent bio-functionalmaterials has some good biological characteristics (biocompatibility as thecore) and some special or specific function. Clinically we always chose inertmaterials for medical use before, however, most of these materials are of thechemical synthesis of polymers, which do not have good biocompatibility anddegradation and often caused the immune system rejection when implanted inhuman body. That is the question that hard to be solved. In recent years, withthe increase of clinical demand for functional biological materials and relatedresearch, the use of new types of biological material is gradually on the rise. Asclinical required, they usually need to have the following characteristics:(1) has excellent biocompatibility and do not cause serious inflammation andimmune responses when implanted in the body;(2) has a goodbiodegradability. Menwhile, degradation products do not has adverse effectson organisms;(3) non-toxic;(4) belongs to biologically active macromolecules,with specific features according to certain requirements, such as the materiaksthat are used as scaffolds of anti-cancer drug delivery system need to have theability to inhibit growth of cancer cell.(5) has a good physical and chemicalproperties, can be produced upon request into the appropriate shape or state.(6) a wide array of sources. Finding this biological material has been aresearch focus.In this experiment, we study two important chitosan derivatives:N-carboxymethyl chitosan and Hydroxyethyl chitosan, to observe the physicaland chemical properties of the two derivatives, use them to make films andstudy the physical and biological properties of the these films Next, study thebiocompatiblity, biodegradable ability and ability of those two film to inhibit thegrowth of fibroblast cell, provides a theoretical basis for the furtherdevelopment of them as excellent biological material, and, at same time, tobroaden the the range of chitosan’ application.Methods:1the preparation hydroxyethyl chitosan (HECTS), and N-Carboxymethylchitosan (N-the CMC).2purification of the two kinds of chitosan, study of their physical and chemicalproperties: hydroxyethyl substitution degree, molecular weight, degree ofdeacetylation and FITR etc.3, the preparation of these two kind of films in dark condition, Study the percentof water absorption and swelling ratio. Study the biocompatibility and thedegradation by subcutaneous implantation and muscle implantation test,fibroblast growth test, evaluate films’ inhibitory of the growthof fibroblast cell. Results:1. Synthesized the N-CMC and HEC, make clear the optimal synthesisscheme and the mixture ratio.2, Two kinds of film were prepared by cross-linking ratio of80:1, Filmshave good permeability and hydrophilic and have a certain degree of inhibitionto fibroblasts cell, Films which are used in rats in vivo buried membraneexperiments show that those two films can be gradually degraded, thebiocompatibility of the two materials is decent.3. cell experiments: N-CMC has a relatively strong effect of inhibition offibroblast cell, in contrast, HEC inhibit the growth of cell weakly.Conclusion: the diaphragm of the two materials were prepared with goodflexibility, permeability, hydrophilicity and mechanical strength, in vitroexperiments shows that their good biocompatibility and degradation. Cell testshows that two materials have the ability to inhibit the growth of fibroblast cell.for as glaucoma filtration surgery implant material to provide a theoreticalbasis。... |
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