Fig. 2

Optimization of the composition. a UV–vis–NIR spectra of the WONPs suspension post the addition of different amounts of H₂O₂. The oxidation of WONPs into WO₃ was reflected in real-time by the loss of the characteristic peak at 930 nm. b The efficacy of WONPs at a fixed concentration (2.4 × 10¹⁶ particles per mL) in eliminating singlet oxygen generated from Ce6 that differed in amount. The temperature elevation of the suspension was measured right after the second-round laser irradiation. Data are presented as mean ± s.e.m. (n = 3). The cartoons inserted in the image illustrate the changes of WONPs that were partially (middle) to entirely oxidized (right). c The level of intracellular ROS measured using the H₂DCFDA probe. For cancer cells, they were all incubated with Mito(T)-pep-Nuc(T), and the only difference is the enzymatic activity of Cathepsin B (normal: NPs + Cathepsin B; inhibited: NPs). For hepatocytes, they were incubated with either Mito(T)-pep-Nuc(T) or a mixture of Mito(T) and Nuc(T) under an identical condition. d The XPS spectra of tungsten element in Nuc(T) of Mito(T)-pep-Nuc(T) at Day 4 post their incubation with mouse serum at 37 °C. The plot was deconvoluted to show the proportions of both W(V) and W(VI) species. The profiles of pristine WONPs served as control and was shown for comparison