Release of bioactive agents from mesoporous silica nanoparticles for biological applications

Abstract

The high surface area, pore volume, and biocompatible/ biodegradable silica matrix of mesoporous silica nanoparticles (MSN) has led to extensive investigation into these materials as carriers for bioactive agents. These agents can be loaded into and sheltered within the mesopores, then released at the target site either through simple diffusion or in response to specific stimuli. Owing to the facile surface modification of MSN, stimuli responsive MSN is frequently synthesized through the covalent linkage of an organic functionality, capable of changing conformation in response to a given stimuli, to the silica surface. However, this goal can also be accomplished through coating of the particle surface with an enzymatically digestible polymer. In this work, vanillin loaded MSN coated with the linear glucose polymer amylose or branched glycogen is proposed as a salivary α-amylase responsive system for drug delivery. The starch cap is capable of retaining vanillin within the MSN pores until the enzyme is introduced, making delivery specific to the oral cavity. This target offers benefits such as higher patient compliance and the negation of first-pass metabolic effects. In addition, the use of large pore MSN for the release of large, homotetrameric protein and silver-MSN nanocomposites for antimicrobial applications are discussed.