Preparation And Application Of Nano Micro Carrier Based On Natural Polysaccharide

Natural polysaccharide is a extensive sources. It is safe and low toxicity. It is biocompatible and biodegradable. It has been widely use in food and biomedical field. It can be modified for different application and prepare many kinds of carriers with different properties. Nano micro carriers can connect targeted ligand for targeted drug delivery. Nano micro carriers based on natural polysaccharide will have a potential use in the delivery of food bioactives and drugs.This thesis focuse on the preparation and application of oxidized konjac glucomannan (OKGM) microspheres and oxidized starch nanospheres. The main results are as follows:1. The degree of oxidation 80%(DO80) OKGM was prepared by TEMPO-oxidation. The microspheres were made using emulsion polymerization method, with ferric ions use as cross-linking agent. The microspheres size was homogeneous, average diameter was 19μm.2. The negatively charged OKGM microspheres can adsorb positively charged anthocyanidins. The odsorption capacity and release percentage between OKGM microspheres and anthocyanidin can be influenced by pH and salt concentration. The maximal amount of adsorption was 96 mg anthocyanidin/g OKGM microspheres at pH 3. The odsorption capacity decrease with the salt ionic strength increasing. While the release percentage was minimum at pH 3. The release percentage increase with the salt ionic strength decreasing.3. The microspheres were sensitive with strong H+ ionic, which made the microspheres degradation at simulated stomach conditions. Chitosan oligosaccharides (COS) was applied on OKGM microspheres to strengthen the OKGM microspheres’structure under stomach condition. COS oligomers were cross-linked with glutaraldehyde. So the microspheres can help the anthocyanidins go through the stomach conditions without release until reash the intestinal condition for sustainable release, because of its high stability in low pH stomach condition.4. Oxidized starch of various degree of oxidation was prepared by TEMPO-oxidation. The nanospheres of degree of oxidation 30%(DO30) oxidized starch was select for further study. The DO30 nanospheres average diameter was 30nm-50nm.5. The zeta potential and size of nanospheres were influenced by pH and salt concentration. With the pH increasing, zeta potential decrease and size increase. With the ionic increasing, zeta potential increase and size decrease.6. Targeted delivery carrier was prepared by chemical reaction with PEG and RGD sequencly. FITR and HNMR analysis revealed that PEG and RGD was successfully connect.7. The nanospheres can adsorb Dox. The maximal amount of adsorption was 0.062mg/mg nanospheres. The release percentage was influenced by pH. The maximal release percentage reached 90% at pH 5.8. The targeted delivery carrier enhance the uptake by target tumor cells (LLC), and improve the drug delivery and anti-tumor efficiency. It will be a potential drug carrier for targeting therapy.