Immunological Analysis After Implantation, Biomimetic Mineralization Of Zein Scaffolds And The Application Of Azobenzene-Cholesterol As A Sunscreen

This thesis explored the immunological analysis methods after implantation of zein into rats, the biomimetic mineralization of zein scaffolds and the application of CDBA-liposome as a sunscreen.Method:Eight male Sprague Dawley (SD) rats were randomly divided into the normal group without implantation and the zein tube group. Flow cytometry detected the amounts of CD4+and CD8+T lymphocytes in the peripheral blood at one, two and four weeks after subcutaneous implantation. Besides, methods for preparation of parafin section of zein after both muscular pouch implantation and subcutaneous implantation were also tried for the histological observation.Zein scaffolds with dimensions of4×4×4mm were immersed in SBF at different conditions to achieve biomimetic mineralization. The morphology and composition of the coating formed on zein scaffolds were analyzed by scanning electron microscopy (SEM), and the ratio Ca/P was calculated.4-cholesterocarbonyl-4’-(N, N’-diethylaminobutyloxy) azobenzene (CDBA) was arranged into liposomal membrane. The stability of doxorubicin (DOX)-loaded CDBA-liposome and the release of DOX when mixed with propylene glycol or glycerol were studied. The photo-isomerization and the structure of CDBA-liposome were evaluated after periodic UV and visible light irradiation. Furthermore, the UVA and UVB protective effects of CDBA-liposome were evaluated by the critical wavelength method and the ultraviolet spectrophotometer method, respectively. Moreover, in vivo tests to estimate the UV protecting efficacy of CDBA-liposome was carried out with nude mouse.Results and Conclusions:The change of CD4+and CD8+T lymphocytes in the peripheral blood was successfully detected by flow cytometry. One week after subcutaneous implantation, the levels of CD4+(P<0.01) and CD8+(P<0.05) T lymphocytes decreased. Two and four weeks post implantation, no significant difference was shown in the levels of CD4+and CD8+(P>0.05) T lymphocytes. One, two and four weeks after subcutaneous implantation, the ratios of CD4+/CD8+had no significant changes in the zein tube group compared with the control group (P>0.05), which indicated that the immune responses weren’t activated after zein tubes implantation. An improved method of preparing integrated paraffin sections of the implanted material was used for further histological observation.The Ca/P ratio of each surface of the zein scaffold had the lowest variance when zein scaffolds were immersed in5X SBF in a shaker bath set at60rpm with the temperature maintained at37℃, showed a better biomimetic mineralization of zein scaffolds. The standard deviation is0.074and the mean value is1.292.CDBA has absorption ability in the UV range. Periodic UV and visible light irradiation did not affect the photo-isomerization and the structure of CDBA-liposome, and could recover its absorption ability in the UV range.. That is to say, CDBA-liposome has the potential to be used as a repeatable sunscreen cosmetic. Furthermore, the stability and photo-isomerization of CDBA-liposome could not be affected when mixed with propylene glycol and glycerol. What’s more, the inclusion in CDBA-liposome could be released after the photo-isomerization. According to the method of instrument measurement, CDBA-liposome had UVA and UVB protective function, which could be used in winter, cloudy and summer morning and evening. The in vivo experiment also confirmed that the CDBA-liposome could provide a good protective efficacy under UV irradiation. These data demonstrated that CDBA-liposome has the potential to be used as commercial sunscreen cosmetics.