Titania/iron oxide nanoplatform operates as hydrogen peroxide enriched vector for amplification of fenton catalytic efficiency in cancer theranostics

The Fenton catalytic ability of Fe3O4 can be significantly amplified by modifying small amount of TiO2 on the surface, affording an efficient Fenton reaction nanoplatform to enrich the inherent H2O2 within the tumor microenvironment without the need of additional delivery of toxic chemotherapeutics. Such nanoplatform features high biocompatibility and exhibits excellent tumor inhibition, showing great potentials in cancer theranostics. [Display omitted] •The efficiency of Fenton reaction mediated by iron oxide alone is relatively low.•Increasing the concentration of H2O2 in tumor by drugs may cause other toxic effects.•TiO2 can effectively adsorb hydrogen peroxide in tumor to form peroxide complexes.•TiO2/Fe3O4 nanoplatform can amplify the efficiency of Fenton reaction in tumor. The •OH induced apoptosis is a promising strategy for tumor treatment. Many current •OH generating systems are highly dependent on H2O2 in tumor microenvironment (TME). However, the H2O2 level in the TME is not high enough to produce sufficient •OH. Herein, we develop a biomimetic nano-catalyst based on TiO2/Fe3O4 platform (designed as “FTP”) to initiate a cascade of biochemical reactions to produce •OH in TME. In this platform, the modified TiO2 acting as H2O2 adsorber can promote the concentration of H2O2 around and significantly amplify Fenton reaction efficiency of Fe3O4 to induce more cell apoptosis through •OH mediated mechanism, thereby resulting in remarkable inhibition of tumor growth. The as-synthesized FTP, with diameter of 7.20 ± 1.80 nm, could efficiently accumulate in tumor via the enhanced permeability and retention (EPR) effect and act as negative T2-weighted MRI contrast agent. The results showed that the FTP could induce a significantly higher cytotoxicity profile than naked Fe3O4 nanoparticles. More specifically, the FTP exhibited significant therapeutic performance of tumors than naked Fe3O4, TiO2, and control groups.