Degradable inorganic/polymer core-shell microspheres for pH-triggered release of indole-3-acetic acid

The narrowly dispersed functional silica/poly(di(metacryloylooxy-1-ethoxy) methane-co-acryl amide) (SiO2/P(DMOEM-co-AAm)) core-shell microspheres were synthesized by distillation precipitation polymerization of DMOEM as a degradable crosslinker and AAm as a functional monomer with the presence of 3-(methacryloxy)propyltrimethoxysilane (MPS) modified silica microspheres as seeds. Indole-3-acetic acid (IAA) can be efficiently loaded into the microspheres with a loading capacity of 37.5% via hydrogen-bonding interaction between the carboxylic acid group of IAA and the amide groups on the surface of SiO2/P(DMOEM-co-AAm). The loaded IAA can be triggered released by pH due to the presence of pH-responsive crosslinker (DMOEM).