Degradation of Mesoporous Silica Materials in Biological Milieu: The Gateway for Therapeutic Applications

Since early developments in the field of mesoporous materials, mesoporous silica has attracted large interest in drug delivery, as they display an ordered array of pores with diameters ranging from 2 to 50 nm, which can be loaded with drugs. Mesoporous silica dissolves at physiological pH, triggering the release of loaded drugs. Several studies have focused on determining the key factors that determine the biodistribution, biocompatibility, and toxicity both in vitro or in vivo. However, in vivo studies focused on the degradation of mesoporous silica materials are very scarce, despite its relevance for drug release. In this perspective, recent works addressing mesoporous materials degradation in the context of drug delivery are discussed, first from a physicochemical point of view, and secondly in in vivo settings, in animal models that are the closest conditions to the encountered when the mesoporous materials are administered to humans. Finally, further discussion about the future directions in the design of mesoporous nanomaterials for therapy and for the study of their biological fate are presented.