Fig. 2. (A) Schematic illustration of the NIR light-controlled CHA fluorescence sensing mechanism for FAP detection; (B) fluorescence emission spectra of the core UCNP and core–shell UCNP under 808 nm excitation; (C) energy transfer principle diagram of the core–shell UCNP structure; (D) PAGE analysis of the photoactivation and CHA reaction mechanism (lane 1: S1-SPT duplex; lane 2: S1-SPT + FAP; lane 3: U–H1; lane 4: U–H1 under 808 nm irradiation; lane 5: H2; lane 6: S1-SPT + FAP + U–H1 (without H2); lane 7: complete system (S1-SPT + FAP + U–H1 + H2) under 808 nm irradiation); (E and F) fluorescence emission spectra of the sensing system under different experimental conditions measured at 663 nm.
