A Novel CaO2@Tannic Acid-Fe(III) Nanoconjugate for the Enhanced Chemodynamic Therapy of Tumour.

In this work, we designed a new type of nano-system (CaO 2 @TA-Fe(III)) for the enhanced CDT of tumours in which the polyphenolic compound-tannic acid (TA) and Fe 3+ formed a TA-Fe nano-coating on the surface of calcium peroxide (CaO 2 ) nanospherical aggregates. When the CaO 2 @TA-Fe(III) nanoconjugates reach the tumour site, the CaO 2 contained in the nanoconjugates produces H 2 O 2 after disintegration in tumour cells, and the carried TA rapidly reduces Fe 3+ to Fe 2+ , solving the two major shortcomings in CDT of (1) insufficient content of H 2 O 2 in cancer cells, and (2) low catalytic efficiency of the Fenton reaction. Additionally, the ∙OH produced in the Fenton reaction induces oxidative stress for the tumour cells, promoting the occurrence of the "calcium overload" process, and thereby accelerating the death of tumour cells. Experimental results in vitro and in vivo showed that CaO 2 @TA-Fe(III) nanoconjugates can effectively kill cancer cells. We believe that the CaO 2 @TA-Fe(III) nanoconjugates are a promising new nano-platform for highly effective tumour treatment.