P(VPBA-DMAEA) as a pH-sensitive nanovalve for mesoporous silica nanoparticles based controlled release

A pH-sensitive controlled release system was proposed in this work, which consists of mesoporous silica nanoparticles (MSNs) functionalized on the pore outlets with poly(4-vinylphenybronic acid-co-2- (dimethylamino)ethyl acrylate) P(VPBA-DMAEA)]. Four kinds of P(VPBA-DMAEA)-gated MSNs were synthesized and applied for the pH-sensitive controlled release. The results showed that P(VPBADMAEA) can work as a pH-sensitive nanovalve. The release behavior of the hybrid nanoparticles could be adjusted by changing the mole ratio of VPBA and DMAEA. With the increasing of the mole ratio of VPBA, the leakage of the entrapped molecules in the pores of MSNs could be decreased at neutral and alkaline conditions. By altering the pH of buffer from 4.0 to 8.0, the valve could be switched "on" and "off" reversibly. In addition, cells viability results indicated that these P(VPBA-DMAEA)-gated MSNs had good biocompatibility. We believe that these MSNs based pH-sensitive controlled release system will provide a promising nanodevice for sited release of drug delivery.