Fabrication And Properties Of Drug-loaded Silica/Sericin Hybrid Microcapsules

Hybrid microcapsules are new types of composites composed of microcapsules coated with other substances.Due to their functional flexibility,hybrid microcapsules are attracting more and more attentions,especially as drug carriers,which have an excellent application prospect in tumor-specific targeted therapy and drug controlled release.There are many methods for preparing hybrid microcapsules,but the preparation and application of hybrid microcapsules are still very challenging without affecting the functionality and packaging efficiency.This study reports a facile approach for the synthesis of silica hybrid microcapsules using self-made silk sericin microcapsule as matrix in an environment-friendly way.We call them hybrid colloidosomes due to the arrangement of silica.The arrangement of silica colloids on the silk sericin microcapsule are orchestrated through controlling the reaction parameters.Doxorubicin is used as a hydrophilic anticancer drug model.It is encapsulated into the colloidosomes in a mild aqueous solution and releases under different external environments.The biocompatibility of the materials and the inhibitory effect of the drug-loaded microcapsules/hybrid microcapsules on the tumor cells are evaluated by cytological evaluation.In addition,the targeting factors folate folic acid is grafted onto the surface of the drug-loaded hybrid microcapsules and co-cultured with Hela cells whose surface receptor is overexpress.And study the targeting of drug carriers.The research content and results as follow:1.The preparation of silica/sericin hybrid microcapsules and the characterizationSericin microcapsules were prepared by inducing calcium ion in aqueous solution by one-step reaction.Tetraethylorthosilicate was added and hydrolyze to form silica particles.Silica/sericin hybrid microcapsules were prepared by electrostatic adsorption on the surface of microcapsules.The composition of hybrid microcapsules was analyzed,and the main material on the surface of the hybrid microcapsules was silica.The thickness of the silica layer was uniform and the morphology was stable.2.The influence of different reaction conditions on the silica shell and performanceevaluationThe hybrid microcapsules with different morphologies were prepared by selecting different reaction parameters.O n the basis of the above results,the thickness of the silica shell was controlled by controlling the reaction conditions.The existence of the silica shell increases the stiffness of the microcapsule,which provides the basis for the protection of the microcapsules and the subsequent encapsulation and release of the drug.Sericin microcapsules and silica / sericin complex capsules all have good biocompatibility.3.Silica/sericin hybrid microcapsules as drug carriersThe optimal loading condition of doxorubicin hydrochloride in sericin was designed.The loading rate of doxorubicin was calculated to be about 20 % by ultraviolet spectrophotometer.The release rate of doxorubicin hydrochloride was different in different external stimuli.The release rate of doxorubicin was obviously slower under the silica protective layer on the surface of the composite capsules.The growth and proliferation of MG-63 cells were also inhibited by doxorubicin.The cell survival time was directly proportional to the thickness of the silica layer.Folic acid was grafted on the surface of the drug-loaded hybrid microcapsule,co-cultured with Hela cells,to study the targeting effect of targeted drug-loaded hybrid microcapsules.