O-carboxymethyl chitosan based pH/hypoxia-responsive micelles relieve hypoxia and induce ROS in tumor microenvironment

The hypoxia in tumor microenvironment (TME) can upregulate the HIF-1α and PD-L1 expression and cause immunosuppression of tumor. In this study, a carboxymethyl chitosan-based pH/hypoxia-responsive and γ-Fe 2 O 3 /isosorbide dinitrate carrying micelle was designed, and it could catalyze endogenous H 2 O 2 to generate oxygen and relieve hypoxia in TME, so as to relieve the overexpression of HIF-1α and PD-L1 in tumor; meanwhile, it could react with H 2 O 2 to release ROS via Fenton reaction and induce cytotoxicity in tumor. Along with these multiple effects, this carboxymethyl chitosan-based micelles could provide a comprehensive strategy for tumor treatment.