Figure 4.

(A) Schematic illustration of the synthesis procedures of AHTPR NPs. (B) The infrared thermal images and time-dependent temperature elevation of AHTPR at various concentrations under 1.0 W cm⁻² 808 nm laser irradiation. (C) Photothermal stability curve of AHTPR (120 µg mL⁻¹) NPs following on/off NIR laser irradiation (2.0 W cm⁻²) for 5 cycles. (D) UV–vis spectra of AIBI, HTPR and AHTPR. (E) The release profiles of AIBI from AHTPR in PBS with different pH values without or with NIR irradiation (808 nm, 1.0 W cm⁻², 10 min). (F) The generation of alkyl radicals in MNNG/HOS cells after corresponding treatment. (G) Detection of mitochondrial membrane potential (ΔΨm). (H) In vivo thermal images and temperature variation curves of tumor region recorded by using the NIR thermal camera during NIR laser irradiation (1.0 W cm⁻²). (I) The photographs of all tumors taken from mice after various treatments. (J) Tumor volume growth curves of tumor-bearing mice during the administration of different formulations. (K) Tumor weights were measured after various treatments. (L) Body weight changes of MNNG/HOS tumor-bearing mice in different groups during the treatment. (M) H&E and immunohistochemical (TUNEL and Ki-67) analyses of tumor slices in different groups. (*P<0.05, **P<0.01, ***P<0.001). Adapted from Hu H, Deng X, Song Q, et al. Mitochondria-targeted accumulation of oxygen-irrelevant free radicals for enhanced synergistic low-temperature photothermal and thermodynamic therapy. J Nanobiotechnol. 2021;19(1):390. Creative Commons.⁵³

Abbreviations: TPP, triphenylphosphonium; AIBI, 2,2′-azobis[2-(2-imidazolin-2-yl) propane] dihydrochloride; AHTPR, a core–shell nanoplatform composed of RGD functioned PDA as a shell and a TPP modified H-MnO₂ as a core with the encapsulation of AIBI; HTPR, AHTPR without AIBI.