Precision Photothermal Therapy at Mild Temperature: NIR-II Imaging-Guided, HO-Responsive Stealth Nanobomb.

The therapeutic efficacy of photothermal therapy (PTT) under mild temperatures (<45 °C) is hindered as cancer cells can activate heat shock proteins (HSPs) to mend fever-type cellular damage swiftly. The previous attempt fabricated first-generation nanobombs (nanobomb1G) by self-assembly of polymeric NIR-II AIEgens and carbon monoxide (CO) carrier polymer mPEG(CO) to inhibit the expression of HSPs after intratumor injection. A new generation nanobomb (Stealth NanoBomb (SNB)) is developed by self-assembling small molecular NIR-II AIEgens with CO carrier polymer PLGA(CO) coated by PEG-lipid. This design allows for intravenous administration, enabling the SNB to circulate safely in the bloodstream and selectively target cancer cells. Upon accumulation in tumors, the SNB releases CO to effectively suppress HSP expression, enhancing the therapeutic efficacy of mild-temperature PTT. Compared to the previous generation, the SNB offers a safer, more stable, and more efficient CO gas/drug co-delivery system for cancer treatment. This work represents a significant advancement in PTT, providing a promising strategy for enhanced antitumor therapy with reduced systemic toxicity.