All-in-one phototheranostics based on BTP-4F-DMO nanoparticles for NIR-II fluorescence/photoacoustic dual-mode imaging and combinational therapy

Various phototheranostics have recently been developed for phototherapy.Through proper molecular design,the photochemical and photophysical properties of these phototheranostics can be promoted.Herein,an acceptor-donor-acceptor(A-D-A)-structured dye,BTP-4F-DMO,was synthesized and prepared into water-soluble nanoparticles(NPs).The obtained BTP-4F-DMO NPs had strong absorption from650 nm to 850 nm and a fluorescence emission peak at~900 nm that tailed to~1100 nm.The NPs showed a superhigh photothermal conversion efficiency of 90.5%±5%and could simultaneously generate·OH and^(1)O_(2)with a^(1)O_(2)generation quantum yield of 4.6%under 808 nm laser irradiation.Due to these advanced properties,BTP-4F-DMO NPs can switch the role of autophagy from pro-survival to prodeath,thereby further promoting cancer cell death.These features make BTP-4F-DMO NPs a promising multifunctional phototheranostic agent for NIR-II fluorescence/photoacoustic dual-mode imaging-guided synergetic photodynamic/photothermal therapy.In general,this work provides a strategy for expanding the biomedical applications of organic A-D-A-structured phototheranostics.