Antibacterial Effect Of Chitosan Nanoparticles And Evaluation Of Immune Effect

Chitosan, as a natural positively charged polymer which is rich resource, low cost, good biocompatibility and biodegradable, non-toxic, it also has many functions such as antibacterial, sterilization, anti-tumor, improve immunocompetence, promote tissue repair and hemostasis. It has very wide prospect in biomedical field. Chitosan was made into sustained release preparation could reduce the times of administration; it also could improve the drug safety, effectiveness and reliability. The ideal adjuvant should possess many characters such as non-toxic, non-immunogenic, good biocompatibility, biodegradable, can effectively induced or enhanced cellular immunity and long effectiveness, therefore, chitosan has the potential value to develop a new immune adjuvant.Chitosan nanoparticles (CNP) were prepared by ionic cross-linking method, the cross-linking agent is TPP. The bacteriostatic ability was studied at the same time. The particle size analysis and AFM results showed that, the CNP was grainy, grain size was uniform, and had good dispersibility. The particle diameter of CNP which were prepared by four different TPP concentrations was 14.128±0.026nm、29.132±0.032nm. 44.333±0.104nm and 70.284±0.063nm respectively. The study results of bacteriostatic ability were found that CNP shows inhibitory effect against E.coli and S.aureus, the effect is better than chitosan, and the inhibitory effect of CNP against S.aureus is superior to E.coli slightly.CNP was loaded with Bovine Serum Albumin (BSA) as model drug by adsorption. The effect of adsorption conditions on adsorption rate was discussed; in vitro release behavior of CNP load with BSA was studied subsequently. The result showed that the adsorption rate was 21.82±1.43% after optimum adsorption conditions, the cumulative release amount of BSA from CNP was 32.98±2.35%, and it indicated good sustained-release profile of CNP. In the study of in vivo immune, bovine coronavirus N protein as model drug adsorption onto CNP, the adsorption rate was reached to 73.26±1.32%. The BCV-N load CNP was used to immunize BALB/c mice by injection. The dynamic antibody level of IgG, IgM and IgA in serum was monitored by indirect ELISA. The result showed that, the sustained release effect of CNP was significantly, and it has non-immunogenic, it could significantly increase the IgG level of mice after immunized.In conclusion, CNP adsoption with BCV-N can be prepared by ionic cross-linking method. The prepared CNP is safe and has good sustained release effects. CNP is a potential new immune adjuvant for the transport of BCV-N.