Recent advances in the pH-responsive organic–inorganic mesoporous hybrid silica for targeted drug delivery

Exploring innovative drug delivery systems is of significant significance for disease treatment. Among the array of existing drug delivery methods, stimuli-responsive polymer-based mesoporous silica nanoparticles have emerged as highly promising, owing to their gel-like properties, structural robustness, adaptable sizes and shapes, and capacity to accommodate a variety of cargo moieties. Importantly, the existence of surface silanol groups of mesoporous silica nanoparticles allow the attachment of appropriate drugs, imaging agents, and targeting molecules, which amplifies their applicability and enhances their appeal to the scientific community. Various techniques using nanocarriers sensitive to stimuli have been devised to manage drug release and prevent premature dispensing. This review provides an overview of the design and synthesis approaches for pH-responsive delivery in systems based on polymer silica hybrids including the various approaches for the grafting of polymers into the silica and their biomedical applications.