Cantharidin-loaded biomimetic MOF nanoparticle cascade to enhance the Fenton reaction based on amplified photothermal therapy.

The treatment efficiency of the Fenton reaction is expected to be greatly restricted due to problems such as inefficient delivery of Fenton catalysis, limited H2O2 concentration and uneven tumour tissue. Accurate photothermal therapy (PTT) could improve the efficiency of Fenton catalysis to some extent by raising the temperature. However, the heat shock response (HSR) of tumour cells caused by PTT and Fenton reaction would attenuate the treatment effect. In this study, we developed an iron ions-mediated Fenton reaction combined with a PTT treatment platform based on a metal-organic framework, i.e., PPy-CTD@MIL-100@MPCM nanoparticles (PCMM NPs), and further explored the inhibitory effect of PCMM NPs on the heat shock response (HSR). PCMM NPs could accumulate in tumour tissue via the coated macrophage cell membranes (MPCMs) to target inflammatory tissues. The photothermal effect of polypyrrole (PPy) accelerated the release of cantharidin (CTD) and iron ions loaded in the PCMM NPs. CTD, as an HSR inhibitor, could inhibit this response of tumour cells and improve the effect of PTT. Meanwhile, the heat generated during the PTT process could improve the efficiency of the Fenton reaction. This study suggested that PCMM NPs could serve as a combined treatment platform to enhance the Fenton reaction based on amplified photothermal therapy.