Fig. 2. Screening of SPNs for sonodynamic therapy.

a Chemical structures of SPs and small molecular sonosensitizers. b Schematic illustration of the synthesis of SPNs via nanoprecipitation. c Representative TEM image of SPN7. The experiment was repeated independently three times with similar results. d UV–vis absorption spectra of SPNs in 1× phosphate-buffered saline (PBS) solution (pH = 7.4). e ESR spectra of SPN7, PpIX and TiO₂ nanoparticles (20 µg/mL) after US irradiation using TEMP as the trap. f Quantification of sonodynamic ¹O₂ generation for each sample (20 µg/mL) (n = 3). g ESR spectra of SPN7 (20 µg/mL) after 1, 2, 3, and 4 cycles of US irradiation with TEMP as the trap. h Relative ¹O₂ generation for SPN7, ICG, PpIX and AO (20 µg/mL) after different cycles of US irradiation (n = 3). US-irradiation conditions: 1.0 MHz, 1.2 W/cm², 50% duty cycle, 5 min for each cycle. Data are presented as mean values ± SD. Source data are provided as a Source Data file.