LAUSR

To maximize the utilization and response to the high oxidative stress environment of tumor sites while avoiding the dilemma of enhancing ROS response in a single way, Mitochondria-targeting combined with fluorescent self-reporting polymeric nanocarriers (1K-TPP and 2K-TPP) with grafted structures were synthesized via chemoenzymatic method in a high yield used to jointly enhance drug delivery of endogenous ROS responses. 1K-TPP and 2K-TPP loaded DOX at a high content over 12% and formed homogeneous spherical micelles. In vitro, both of them showed promising high-sensitivity (detection limit below 200 nM H2O2), fast response and ratiometric fluorescent self-reporting properties (fluorescent enhancement more than 200 times) to ROS and excellent stability of under physiological conditions, while achieved rapid release of the DOX in response to 1 mM H2O2. Cell co-localization experiments exhibited that they had favorable mitochondrial targeting, and mitochondrial isolation experiments also confirmed that the TPP-modified 1K-TPP selectively accumulated nearly 3 times in mitochondria than that in total cells. The internalization of 1K-TPP and 2K-TPP into cancer cells was greatly improved by nearly 200% compared with that of unmodified control (1K-OH and 2K-OH) and also explored a unique energy-dependent endocytosis. Furthermore, stimulation of endogenous ROS enhanced the green fluorescence intensity (up to 51.4%) of the linked probe so as to destroy the internal structure of the nanocarriers, achieving self-reporting of the drug's intracellular release and tracking the intracellular location of nanocarriers. The cytotoxicity of DOX-loaded 1K-TPP and 2K-TPP in tumor cells with higher ROS content exhibited statistically superior to that of 1K-OH and 2K-OH, benefiting from the extremely good endogenous ROS response sensitivity leading to the differential selective release of drugs. These results demonstrate the potential of 1K-TPP and 2K-TPP, especially for 1K-TPP, as mitochondria-targeted, fluorescent self-reporting nanocarriers for combined enhancement of endogenous ROS responsiveness.