Fig. 5
PA property and in vivo PA imaging with iMIPT NPs. a PA spectra of various NPs indicated. b PA signal (excited by 680 nm pulsed laser with a laser fluence of 17.5 mJ cm−2 and a repetition rate of 10 Hz) comparison of different agents at the same concentration of 25 μM based on NDTA, 2TPE-NDTA, 2TPE-2NDTA, MB, and the repeat unit of semiconducting polymer. Error bars, mean ± s.d. (n = 3). **P < 0.01, in comparison between 2TPE-2NDTA-doped NPs or 2TPE-NDTA-doped NPs and other 3 agents (NDTA-doped NPs, SPNs, and MB) using one-way ANOVA. c Plot of PA intensities of 2TPE-2NDTA-doped and 2TPE-NDTA-doped NPs in phantoms against number of laser pulses at 730 nm. The total laser exposure time was 800 ms for 1.16 × 108 pulses. d, e Representative PA images of d tumours and e muscles from 2TPE-2NDTA-doped NP-administrated mice. Before (0 h) and after 2TPE-2NDTA-doped NPs (300 μM based on 2TPE-2NDTA) were intravenously injected into xenograft 4T1 tumour-bearing mice for designated time intervals, PA images were taken upon 730 nm pulsed laser irradiation with a laser fluence of 17.5 mJ cm−2 and a repetition rate of 10 Hz. The ultrasound frequency is 5 MHz. Scale bars, 3 mm in both d and e. f PA intensities of tumour and muscle tissues as a function of time before (0 h) and after intravenous injection of 2TPE-2NDTA-doped NPs. Error bars, mean ± s.d. (n = 3 mice). **P < 0.01 and *P < 0.05, in comparison between tumour and muscle tissues using one-way ANOVA
