Fig. 4
Characterization of BPBBT NPs. a Schematic illustration of BPBBT NPs. b Representative TEM image and size distribution of BPBBT NPs. c Fluorescence emission spectra of BPBBT (10 µM) in THF, 70% THF, 5% THF or BPBBT NPs (10 µM of BPBBT) in water excited at 831 nm. d Photographs and NIR-II fluorescence images of the solutions in (c). e Temperature-time curves of BPBBT NPs (50 µM of BPBBT) in water or BPBBT (50 µM) in 95% water:5% THF under the laser irradiation (808 nm, 1 W cm−2) for initial 10 min, followed by 10 min of cooling. f, g Time constant for heat transfer from the system of BPBBT NPs or BPBBT in 95% water:5% THF is determined to be τs = 175 s or 166 s by applying the linear time data from the cooling period versus negative natural logarithm of driving force temperature, which is obtained from the cooling stage of panel (e). h Release profile of BPBBT from BPBBT NPs in 10% FBS. Data are presented as Mean ± S.D. (n = 3). i Size distribution of 10% FBS, BPBBT NPs in PBS, or BPBBT NPs in 10% FBS at different time points following mixture. Peak 1 from the nanoparticles; Peak 2 from serum. j Fluorescence emission spectrum of 10% FBS, BPBBT NPs in PBS, or BPBBT NPs in 10% FBS for different incubation time
