| Chemodynamic therapy?CDT?based on the Fe???and intra-tumor H2O2-mediated Fenton reaction is an emerging tumor treatment strategy,The highly toxic hydroxyl radical?· OH?produced by the Fenton reaction can effectively kill tumor cells.However,the catalytic efficiency in tumors is crucially limited by Fe???,which greatly limits the rate of the Fenton reaction and thus hinders the further application of CDT.In this article,an endogenous hydrogen sulfide?H2S?accelerated Fe???/Fe???transformation and photothermal synergistically enhanced CDT strategy based on ellagic acid–Fe–bovine serum albumin?EA-Fe@BSA?nanoparticles?NPs?was developed for colon tumor inhibition.details as follows:First,ultra-small EA-Fe @ BSA NPs were prepared via a simple self-assembly strategy.In vitro experiments show that the material has photothermal conversion properties and good T1-weighted magnetic resonance imaging?MRI?performance.Cytotoxicity test,hemolysis test and routine blood test proved that the prepared EA-Fe @ BSA NPs had good biocompatibility from both in vivo and in vitro levels.Secondly,using NaHS to simulate endogenous H2S,the relationship between the valence state of Fe in EA-Fe @ BSA NPs responding to hydrogen sulfide and the production of ·OH was investigated,and further studied the Fe???/Fe???conversion and photothermal enhanced CDT in vitro.The enhanced CDT was investigated in colon cancer cells by calcein-AM / PI staining,and its tumor suppressive effect was proved by treatment experiments in tumor-bearing mice.The results showed that the Fe?III?with low catalytic activity in the EA-Fe@BSA NPs was rapidly reduced to the highly active Fe???by the abundant H2S in colon cancer tissues.Thus,a rapid Fe???/Fe???conversion system was established,wherein highly active Fe???ions were continuously regenerated to improve the CDT efficiency.At the same time,the heating effect of photothermal can accelerate the production of ·OH,thereby improving the CDT efficiency.This strategy based on endogenous H2S accelerated Fe???/Fe???conversion and photothermal synergistically enhanced CDT has been proven in vitro and in vivo,providing new materials and new methods for the diagnosis and efficient treatment of colon cancer. |
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