Construction of dual stimulus-responsive mesoporous silica based on dynamic borate ester bonds
In this work,a new controlled release system based on mesoporous silica nanoparticles was constructed by regulating the formation of borate ester bonds on the pore surfaces.Mesoporous silica nanoparticles with unique central radial pore structure and pore size greater than 4 nm were synthesized by an anion-assisted method.The inner and outer surfaces of the pores were grafted with phenylboronic acid groups through chemical modification.In adding the polymers containing the cis-diol bonds,the borate ester can form with phenylboronic acid,which may regulate the pore space and lead to different loading levels of molecules in the nanoparticles.Relying on the dynamic reactivity of borate ester bonds in the pores(hydrolysis and bond breaking when the pH value is acidic;oxidation and bond breaking with hydrogen peroxide),the release behavior of the encapsulated dyes in the pore can be successfully regulated according to the stimulus-responsive reactions.The results of this study may expand the fabrication strategies of silica structures for controlled release structures and promote the development of efficient drug delivery systems.