Fig. 7. Luminescence lifetime FRET sensor for ONOO⁻ response and HCC detection in the NIR-II window. (a) Schematic of responsive and distinguishable fluorescence lifetime (τ₁, τ₂, τ₃, τ₄) for fluorescence lifetime imaging. (b) Design of FRET sensor based on DSNP@MY-1057-GPC-3 compound for ONOO⁻ detection. (c) NIR-II lifetime imaging DSNP@MY-1057-GPC-3 sensor at various penetration depths before and after responding to ONOO⁻. (d) Noninvasive NIR-II lifetime imaging and MRI of a mouse liver with three HCC lesions. ROI A: healthy hepatic tissue; ROI B–D: tumor lesions distinguished from lifetime imaging. Reproduced from ref. 80 with permission from Wiley-VCH, Copyright 2020.