Preparation And Performance Study The Double-walled Microspheres Of Permeabilization Of Yeast Cells By CTAB As Nuclear And Silk Fibroin As Shell

Objective: The purpose of this experiment was preparation ofdouble-walled microcapsules are composed of permeabilization of yeastcells by CTAB as nuclear and silk fibroin as shell, Loadingantihypertensive drug carvedilol in the cells to achieve a good release effect.So it is particularly important to select the core material and shell materialof double-wall microspheres. Based on a lot of references can be sure thatsilk fibroin is a excellent shell material, and according to our previous basicresearch conjecture that the permeabilization of brewer’s yeast cells byCTAB might be a good nuclear materials. Based on the above analysis wedid the following experiments.Methods: The first part: It is determined the maximum absorptionwavelength of carvedilol by ultraviolet spectrophotometer in the range of200nm-400nm wavelength. The determination method of the encapsulationyield of carvedilol-yeast microspheres and in vitro release of SilkFibroin-coated carvedilol-yeast microspheres or not was established. Thesecond part: The yeast cells treated with or without CTAB, NaCl and acid-alkaline were observed their surface morphology by PCM, the changeof internal structure by TEM, and analysed the change of structure andcomposition by FT-IR、DSC and TGA, the Permeability ability by CLSM.The third part: The yeast cells treated with CTAB, NaCl and acid-alkalinerespectively encapsulated carvedilol and determined its encapsulation yieldby ultraviolet spectrophotometer, the change of structure and compositionwas analysed by FT-IR、DSC and TGA. The forth part: Because theCTAB-treated cells had high encapsulation yield and kept well Integritybased on the previous analysis to choose it as in vitro release experiments,and compared in vitro release experiments of the CTAB-treated cells wascoated with Silk Fibroin turn into double-walled microcapsules with the notcoated’s. The result of Silk Fibroin-coated yeast was observed by SEM.Results: The first part: we confirm the maximum absorptionwavelength of carvedilol is240nm by ultraviolet spectrophotometer in therange of200nm-400nm wavelength. The determination method of theencapsulation yield of carvedilol-yeast microspheres and in vitro release ofSilk Fibroin-coated carvedilol-yeast microspheres or not was established,this method is accurate, reliable high sensitivity and simple operation byThe methodology validation. The second part: the four samples of theuntreated cells, the CTAB-treated cells, the NaCl-treated cells andacid-alkaline-treated cells were were observed by PCM and themorphology first three samples are round, but the acid-alkaline-treated cells were showed irregular shape and high concentration. Moreover, the insideof CTAB-treated cells walls had obvious “black dot” and the inside of theNaCl-treated cells showed shrinkage of some materials, acid-alkaline-treated cells did not appear black spots and color is very shallow. The TEMshowed that CTAB-treated cells basically maintain its integrity, part ofNaCl-treated cells and almost all of acid-alkaline-treated cells have beendamaged. The FT-IR, DSC and TGA spectrum showed that the structure ofyeast cells after different treatment was changed. From the CLSM weknowed that the whole CTAB-treated cells were dyed and the color is deep,NaCl-treated cells and acid-alkaline-treated cells almost not be dyed. Itimplied that the yeast cells increased its permeability after treated withCTAB. The third part: The encapsulation yield of CTAB-, NaCl-andacid-alkaline-treated cells is respectively29.3%,10.51%and2.74%determined by ultraviolet spectrophotometer. The forth part: in vitrosimulated stomach release of carvedilol-CTAB-treated cells showed aburst release of92.2%within the first2h. Nevertheless, the burst release of45%within the first2h and90.4%when24h. the CTAB-treated cells wascoated with silk fibroin turn into double-walled microcapsules thatachieved a significant sustained release. The SEM can the surface of yeastwas coated by silk fibroin.Conclusions: This experiment is established the method ofpermeabilization of yeast cells by CTAB, it had higher drug loadings and kept better integrity of the cell itself compared with other processingmethod. the experiment used silk fibroin coated the carvedilol-yeast andformed double-walled microcapsules are composed of permeabilization ofyeast cells by CTAB as nuclear and silk fibroin as shell, and improved theburst release.