Fig. 3: The activation of disulfide mechanophores and small molecule release via thiol/disulfide exchange from PMBs.

a Optical micrograph, scale bar: 50 µm. The experiment was repeated three times, and similar images were obtained. b Structural composition of PMB-UMB shell. c Photographs of samples under daylight and UV light (λ_exc = 365 nm), (i) PMB-UMB without sonication. (ii) DMSO/H₂O blank. (iii) The filtered solution of sonicated PMB-UMB (0.68 MHz, 15 min). (iv) The filtered solution of sonicated PMBs-UMB (20 kHz, 15 min). d Scheme of mechanophore activation and fluorophore release. e, f UMB release under 20 kHz and 0.68 MHz irradiations. Data are presented as mean values +/− the standard deviation. N = 3 independent sonications. g ¹H NMR spectra (400 MHz) of free UMB and released UMB. h Morphological characterization by optical microscopy, scale bar: 50 µm. The experiment was repeated three times, and similar images were obtained. i Structural composition of PMB-CPT and illustration of CPT release. j Photographs of samples under daylight and UV light (λ_exc = 365 nm), (i) DMSO/H₂O blank. (ii) The filtered solution of sonicated PMB-CPT (0.68 MHz, 15 min). (iii) The filtered solution of sonicated PMB-CPT (20 kHz, 15 min). UPLC elugrams of free CPT and released CPT (20 kHz). k CPT release from PMBs under 20 kHz and 0.68 MHz irradiation. Data are presented as mean values +/− the standard deviation. N = 3 independent sonications. l MTS proliferation assay of negative controls PBS, PMBs and mechanophore-free PMB fragments, positive controls CPT and CPT + US, and ex situ sonicated (0.68 MHz, 15 min) PMB-CPT mixed with HeLa cells. Data are presented as mean values +/− the standard deviation. N = 3 independent sonications. (Supplementary Table 3).