Entrapped polyamines in biomimetically synthesized nanostructured silica spheres as pH-responsive gates for controlled drug release

Abstract

We report here a versatile pH-controlled drug delivery system utilizing the polyamine-mediated bio-inspired mineralization approach. In a single step method suitably functionalized monodisperse mesoporous silica spheres (MMS) are obtained, which when encapsulated with ibuprofen, a nonsteroidal anti-inflammatory drug, lead to pH-responsive controlled release of the drug from the mesoporous channels. The polyamines that are responsible for the silicification process in turn act as molecular gates controlling the drug release in a pH dependent manner. Interestingly, while the presence of a polyamine prevents the drug from releasing out of the pores, its absence in MMS allows the drug to be released at a neutral pH.