Iron-engineered mesoporous silica nanocatalyst with biodegradable and catalytic framework for tumor-specific therapy.

Inorganic mesoporous silica-based nanovehicles are highly promising for drug delivery but still suffer from the disadvantages of lacking functionality and poor biodegradability on account of the inert silica framework. Moreover, conventional cancer therapeutics typically employ toxic anticancer drugs or invasive external irradiations, which will inevitably give rise to severe adverse effects and diminished therapeutic outcome. In this work, we report on the iron engineered framework of mesoporous silica nanoparticles (MSNs) to fabricate a nanocatalyst with biodegradable and catalytic framework via a "dissolution-regeneration" strategy (designated as rFeO-HMSN). Based on the abundant overexpressed hydrogen peroxide (HO) and mild acidic nature in tumor microenvironment (TME), rFeO-HMSN nanocatalyst could trigger in-situ Fenton-like reactions to produce highly toxic hydroxyl radicals (·OH), causing remarkable oxidative damages against tumor cells/xenografts. Additionally, the iron-engineered rFeO-HMSN nanocatalyst could readily collapse via an iron-extraction strategy under protein-rich environment, thereby improving the biodegradability of rFeO-HMSN nanocatalyst. This work paves a promising way to engineer the inert framework of MSN into functional, biodegradable and catalytic nanoplatform, featuring effective tumor-therapeutic outcome and stimuli-responsive biodegradation concurrently.