| Summary: | 博士 === 國立成功大學 === 材料科學及工程學系碩博士班 === 92 === Novel biodegradable chitosan/PEG membrane was prepared by maillard process between chitosan amino group and aldehyde or keto groups of native sugar. Membrane and scaffold type of sugar mediated chitosan/PEG gel have been developed in this research. In part I , by controlling the pH value of sugar, mediating process (surface and solution) and thermal treated temperature, the sugar mediated chitosan/PEG polyblend was prepared. In part II， by mixing bioresorbable b-dicalcium pyrophosphate (b-DCP) ceramic particles to glucose mediated chitosan-Polyethylene glycol (PEG) gel with different weight ratio, the mechanical property of sugar mediated membrane or scaffold was reinforced.
The part I results show that the chemical reaction occurrs in imine bonds (C=N) between sugar and amino groups in chitosan. The equilibrium water content (EWC) value of the sugar mediated membrane is in the sequence of sucrose>D-fructose>glucose and they all present much lower water uptake ability than that of polyblend. All of the sugar-mediated membranes are susceptible to lysozyme. However, glucose and d-fructose mediated membranes have a low cell viability impling that their surface chemistry and structure inhibit the cell growth. The thermal treatment promoted the mediating degree and decreased the EWC value of the sugar mediated membrane. In addition, thermal treatment also changed the cell behavior of glucose and d-fructose mediated membrane. The maillard reaction between chitosan and glucose is favored in high pH condition and the glucose mediated membranes prepared by the solution mediated process have a lower EWC than the surface mediated ones.
The part II results show that the growth of fibroblasts would increase for the extracts obtained from different b-DCP feeding weight composites after soaking for 7 days. It was found that the glucose amine and calcium are gradually released from the composites, which is considered to be nutritious for the growth of the fibroblast. When the b-DCP content is lower than 40wt%, the degradation behavior is mostly controlled by the dissolution of chitosan/PEG matrix, but as the b-DCP content is larger than 50wt%, the degradation behavior is dominated by the low degradation rate of b-DCP granules and physical interlocking structure of the composite. A well connective channel structure with small pores was obtained by scheme II process and the porosity decreases but water retention and density increase as β-DCP content increases.
|
|---|
