Emulsion Preparation And Characterization Of Mesoporous Bioactive Glasses For Drug Delivery

Due to its unique chemical composition and amorphous structure,bioactive glass has demonstrated good biocompatibility,biological conductivity and biological induction.It has been widely applied in bone repair and dental restoration while the study of bioactive glass as drug carrier is relatively rare and scattered.This is mainly because that the preparation of traditional melted bioactive glass requests high temperature and the product is massive and tight with low specific surface area through the grinding process.The sol-gel preparation of bioactive glass has greatly reduced the temperature and mesoporous bioactive glass has been prepared with the help of organic template.However,bioactive glass with distinct mesoporous structure was still faced with the problem of agglomeration which has restrained the further development of bioactive glass as drug carrier.Therefore,the main goal of our research is to prepare mesoporous bioactive glass with good dispersibility and improve the MBG’s drug delivery capacity.In this paper,the oil-water emulsion system was introduced during the sol-gel preparation process of bioactive glass.By optimizing the experiment parameter,a variety of well-dispersed mesoporous bioactive glasses were successfully prepared,and their physical and chemical properties,biomineralization performance,drug loading and release properties,cytological properties and implantation performance were investigated.The main research work and conclusions are as follows:（1）Utilizing the independence of the oil-in-water vesicles in the emulsion system to control the rapid formation and aggregation of bioactive glass precursor,bioactive glass particles（SMBG）with surface mesoporous structure and good dispersibility were prepared.SMBG has a good biomineralization property,a better drug loading efficiency and sustained drug release behavior compared with solid bioactive glass nanoparticles.SMBG can promote the proliferation of MG-63 cells and the osteogenic differentiation within a certain concentration.（2）The surfactant CTAB was used as the template of the mesoporous structure to prepare nano mesoporous bioactive glass（NMBG）with good monodispersity.NMBG demonstrated better hydroxyapatite-forming ability in vitro.And in a certain range,the higher the concentration of NMBG,the better effect of promoting the proliferation and differentiation of MG-63 cells.（3）Based on the preparation of NMBG,monodispersed bioactive glass particles（RMBG）with radial mesoporous structure were successfully prepared by optimizing the preparation process with ultrasonic treatment.The specific surface area of RMBG is as high as 986.353 m²g^-1.The radial mesoporous structure of RMBG is controllable,which is closely related to the amount of CTAB and Ca added during the reaction.The drug loading efficiency of RMBG is much higher than that of common bioactive glass microspheres prepared by template method,and the biocompatibility of RMBG is favourable.（4）Mesoporous bioactive glass（HMBG）with hollow structure was prepared by utilizing the surfactant molecular layer at the oil-water interface in the microemulsion system.CTAB plays a decisive role in regulating the hollow structure and surface mesoporous structure of HMBG during the reaction.HMBG possessed connected mesoporous tunnel through the inside and outside which contributed to the long-term storage and sustained release of drug molecules.Besides,HMBG demonstrated superior biomineralization ability and biocompatibility.（5）Bioactive glass and its drug-loaded samples were investigated in the rats’bone defect repair experiments and nude rats’subcutaneous implant experiments.The results showed that the bioactive glass prepared in this paper had good biocompatibility and inductivity and could significantly promote the regeneration of bone tissue and pulp tissue.At the same time,the drug-loaded bioactive glass samples could effectively release the drug and exert its effect.