Study On Preparation,Characterization And Performance Of Monodispersed/Radial Bioactive Glass

Bioactive glass（BG）is a kind of medical silicate nanomaterials with controllable morphology and particle size,good osteoinductivity,biocompatibility and biological activity,which have critical research significance and application value in the field of bone tissue engineering and soft tissue repair attributed to those unique properties.With the continuous optimization of the preparation technology,the microemulsion method has gradually become one of the most commonly used methods for preparing nanoparticles.Compared with the traditional melting method and sol-gel method,the nanoparticles prepared by the microemulsion method have structural advantages such as controllable morphology,good monodispersity,adjustable pore size and high specific surface area.Therefore,in this paper,two kinds of microemulsion methods were applied to prepare monodispersed bioactive glass（SiO₂-Ca O,BGNs）and bioactive glass with radial mesoporous structure（SiO₂-P₂O₅-Ca O,RMBG）.The structure,mineralization and biocompatibility of BGNs and RMBG were systematically studied.Aiming at RMBG’s unique radioactive mesoporous channel,we further explored its drug loading and release performance and anti-tumor activity in vitro.The main research contents are as follows:（1）In this paper,using the uniform microemulsion droplets formed by water/dichloromethane/absolute ethanol,the monodispersed bioactive glass was prepared by the ultrasonic-assisted surfactant-free microemulsion method（SFMEs）and then explored the best preparation parameters.The experimental results showed that when the calcium source addition time,the silicon source mole percentage and the ammonia water addition amount were respectively150 min,80 mol%and 2.5 m L,the products could be prepared with good dispersibility,regular morphology,particle size range of 224±10 nm,uniform particle size（particle size dispersion index is only 0.006）.Compared with the traditional Stober method,this strategy without consuming a large amount of basic catalysts has good experimental reproducibility,recyclable reagents and the higher purity of the prepared nanomaterials,and it is expected to become a new type of nanomedicine carrier material preparation technology.（2）The microemulsion-assisted sol-gel strategy was used to synthesize radial bioactive glass,and the influence of solution volume ratio,reaction temperature and rotation speed on the morphology,particle size and pore diameter of RMBG was investigated.The results showed that RMBG prepared by the microemulsion-assisted sol-gel method exhibited unique radial mesoporous channels,pore diameter of 6.64 nm,specific surface area of629.23 m²/g,particle size about 231.5±8 nm,uniform particle size（particle size dispersion index was 0.014）and good dispersion.Compared with the traditional microemulsion method,the synthesized nanomaterials using microemulsion-assisted sol-gel method have the advantages of radial mesopores,high specific surface area and more uniform particle size in the paper.（3）The biological activities of the two materials were studied through in vitro mineralization experiments.The two homemade materials,BGNs and RMBG,were immersed in simulated body fluids,centrifuged and washed to collect the mineralized products.The structure,crystal form and surface morphology of the products were detected and analyzed.The experimental results showed that when BGNs and RMBG were immersed in simulated body fluids for more than 3 days,hydroxyapatite could be formed on the surface of the material.As the immersion time increases,the amount of hydroxyapatite produced gradually increases.This phenomenon proved that BGNs and RMBG both have the in vitro mineralization activity.This article examined the in vitro red blood cell hemolysis rate and the survival rate of human embryonic kidney cells（HEK 293T）of BGNs and RMBG to study the biocompatibility.The results of hemolysis experiments showed that the hemolysis rate of BGNs and RMBG in the experimental concentration range of 0.05～1 mg/m L was below 5%,indicating that BGNs and RMBG caused slight hemolysis in the concentration range.MTT experiments showed that the survival rate of HEK 293T cells was greater than 95%in the concentration range of 12.5～200μg/m L for BGNs and RMBG,indicating that BGNs and RMBG with good biocompatibility have reached the relevant standards for biocompatibility of medical materials.（4）Using the anticancer drug doxorubicin hydrochloride（DOX·HCl）as a model drug,the drug loading and encapsulation efficiency of RMBG with different drug loading ratios were investigated.The in vitro release performance of RMBG was conducted in a simulated environment with different p H values.The experimental results showed that the drug-loaded of RMBG-DOX·HCl microspheres with a drug loading ratio of 1:1 were45.88±0.3402%,an encapsulation rate of 84.77±1.1504%.From the results,it can be seen that the drug loading rate of the radial bioactive glass increased with the increasing of drug loading ratio.The results showed that as the p H value decreased,the drug release rate gradually increased,illustrated that the drug release behavior of RMBG drug-loaded microspheres was p H-responsive,and the drug release time was longer than 96 h,which had sustained release.（5）In this paper,the MTT method was used to detect the inhibitory of RMBG drug-loaded microspheres to Huh 7 cells and He La cells.The results of anti-tumor activity experiments showed that as the carrier concentration increases,the survival rate of Huh 7 cells and He La cells decreased.When the drug concentration was 50μg/m L,the survival rate of Huh 7 cells and He La cells were 32.69%and 9.44%.It proves that RMBG drug-loaded microspheres have a stronger inhibitory effect on the survival of He La cells.The results of apoptosis experiments showed that when the concentration of RMBG-DOX·HCl was 3.125μg/m L,the apoptosis rate of He La cells can reach 14.69%.As the concentration of RMBG-DOX·HCl increases,the number of apoptosis increases,which proves RMBG can successfully transport drugs into target cells and successfully cause apoptosis.The radial bioactive glass is expected to become a novel drug carrier nanomaterial for drug sustained release and targeted therapy,and has potential application prospects in the fields of drug delivery systems and hard tissue engineering.