Preparation Of Nature Macromolecule Nanoparticles And The Research On Its Application

This thesis describes current approaches for the preparation of biodegradable polymers nanoparticles and their applications research in medical field. Two kinds of natural macromolecules biodegradable polymers, chitosan and starch, were used in this experiments. Chitosan nanoparticles (CSNP) dialdehyde starch nanoparticles (DASNP) were prepared respectively by polyelectrolyte Ionic gelation re-action and microemulsion method(W/O),and their physical and chemical properties were discussed. Furthermore, several applications were researched.The main content in this thesis: (1)CSNP was prepared by ionic gelation reaction and then it was used as a template for preparation of Red selenium(Se)nanoparticles (Red-SeNP) with redox reaction of vitamin C (A.A) and sodium selenite. The average diameter of Red-SeNP determined by Zeta-Sizer was about50nm. Fluorescence analytical method was applied in detecting the anti-oxidation property of Red-SeNP, and the cell experiments (MTT and growth curve experiments) showed its higher biological activity than inorganic selenium. From these series of experiments, it indicates that CSNP is a potential natural, biodegradable nano-template material. (2) Preparation of DASNP by redox reaction of sodium periodate and starch(St).compared with traditional reaction in aqueous solution, DASNP shows its much better property, according to optimize reaction conditions, such as reactant concentration and proportion, temperature, pH, rotation speed and so on. Thereby, the steady DASNP with excellence property was prepared and its structure, grain diameter, decentralization and thermal stability were determined by IR spectrum, SEM, and thermal analyzer. Also, its biological activity was experimented with mammary cancer cell MCF-7, using MTT method. Also, some applications of DASNP in medical filed were researched: firstly, its antibacterial property was tested by standard colony counting method with coli form, compared with traditional antimicrobial glutaric dialdehyde, and the experiments result showed that DASNP has excellent antibacterial capability, so it is indicate that DASNP will be a potential natural low-toxicity antimicrobial material in the near future; The active dialdehyde group of the particles was considered as a drug carrier for anti-cancer drug doxorubicin (DOX) with amino group. The complex of them was named DOX-DASNP, then, its anti-cancer effect in MCF-7 cell and drug releasing were observed. The result shows DASNP can not only control the drug releasing, but also enhance the drug effect. As a new type drug carrier from natural material, DASNP should have wide application in times to come.In conclusion, the natural macromolecule polymer nanoparticles from chitosan and starch, are provided with biodegradable, low-toxicity performance, simultaneity, according their active chemical property, they can be applied as a natural material in medical field.