In vivo second near-infrared fluorescence and ratiometric photoacoustic dual-modality imaging of glutathione

The level of glutathione (GSH) is significantly associated with numerous pathological processes, thus, real-time detection of the GSH level is of significance for early diagnosis of GSH-related diseases. Herein, we developed in vivo second near-infrared (NIR-II) window fluorescence (FL) and ratiometric photoacoustic (RPA) dual-modality imaging of GSH using a GSH-activatable probe (LET-14). LET-14 was synthesized based on a rhodamine hybrid xanthene skeleton with a FL shielding 2,4-dinitrobenzene sulfonyl group that can be specifically cleaved by GSH, thus resulting in a markedly bathochromic-shift absorption, a 6.5-fold increase in NIR-II FL intensity (FL 920 ) and a 13-fold increase in RPA signal (PA 880 /PA 705 ) in vitro . Intriguingly, LET-14 exhibits good selectivity and sensitivity for NIR-II FL and RPA dual-modality imaging of GSH in 4T1 tumor-bearing mouse model. Our findings develop an in vivo detection tool of GSH, which has great potential in the field of cancer diagnosis.