Integrating autophagy inhibition and ROS clearance in biohybrid nanoparticles for low-temperature cancer photothermal therapy

Photothermal therapy (PTT) demands efficient cancer ablation at relative low temperatures and minimal thermal damage to normal tissues, but suffers from both the protective autophagy-related thermal resistance in cancer cell and reactive oxygen species (ROS)-induced damage to normal cells. Here, we screened out curcumin-Fe ultrasmall nanoparticles (Cur-Fe) that manifested efficient photothermal conversion efficiency (η = 43.38 %) and ROS scavenging ability. Additionally, CRISPR/Cas9 plasmids (pCas-ATG5/ATG7) were also constructed to safely and precisely knockdown the protective autophagy for thermal resistance alleviation. The core Cur-Fe/ATG@^TKPF (CFA@T), which was composed of anionic Cur-Fe and pCas-ATGs, was encapsulated by cationic thioketal-crosslinked and fluorinated polyethyleneimine (^TKPF) via electrostatic interaction. Further, CFA@TC was formed by CFA@T coated with an acidic pH-responsive shell OHC-PEG-CHO via Schiff base. Attributed to its dual responsiveness to pH and ROS, CFA@TC exhibited efficient tumor targeting and uptake following intravenous injection. Upon irradiation with a 652 nm laser, CFA@TC demonstrated enhanced efficacy in eradicating cancer cells by inhibiting autophagy, while concurrently mitigating inflammatory responses through intracellular ROS scavenging in vivo and in vitro. Taken together, our study provides a proof-of-concept that CRISPR can be effective for autophagy inhibition, and its integration with ROS-induced inflammatory responses relief can further improve PTT.