Fig. 6

In vivo preoperative PA imaging and intraoperative fluorescence imaging. a Representative time-dependent PA images of subcutaneous tumours from mice intravenously injected with RClosed-YSA and RClosed NPs (800 μM based on RClosed-DTE-TPECM, 100 μL), respectively. Scale bars, 2 mm. b Plot of PA intensity at 700 nm in tumour versus time post injection of RClosed-YSA or RClosed NPs. Error bars, mean ± s.d. (n = 3 mice per group). *P < 0.05, in comparison between RClosed-YSA and RClosed NPs using unpaired Student's t-test (two-tailed). c Representative brightfield images of RClosed-YSA NP-treated tumour-bearing mice before and after surgery as well as representative fluorescence images of mice with complete surgical resection of tumours, followed by 610 nm red light (0.3 W cm⁻²) irradiation at the operative incision site for 5 min. Scale bars, 3 mm. FL fluorescence, IT irradiation time. d H&E stained tissues at the operative incision site in c indicate no residual tumours left behind. Scale bar, 1 mm. e Representative fluorescence images of RClosed-YSA NP-treated mice with residual tumours post surgery. The operative incision site was irradiated by 610 nm red light (0.3 W cm⁻²) for 5 min. The red dashed circles in c and e indicate the tumour/operative incision site. The red arrow shows the residual tumours with a diameter below 1 mm. Scale bars, 3 mm. f, H&E stained tissues at the operative incision site in e confirm the existence of residual tumours. Scale bar, 0.5 mm