An Activatable Afterglow/MRI Bimodal Nanoprobe with Fast Response to H2S for In Vivo Imaging of Acute Hepatitis

Accurate detection of hepatic hydrogen sulfide (H2S) to monitor H2S-related enzymes' activity is critical for acute hepatitis diagnosis, but remains a challenge due to the dynamic and transient nature of H2S. Here, we report a H2S-activatable near-infrared afterglow/MRI bimodal probe F1-GdNP, which shows an "always-on" MRI signal and "off-on" afterglow signal toward H2S. F1-GdNP shows fast response, high sensitivity and specificity toward H2S, permitting afterglow imaging of H2S and evaluation of cystathionine gamma-lyase (CSE)'s activity in living mice. We further employ the high spatial-resolution MRI signal of F1-GdNP to track its delivery and accumulation in liver. Importantly, F1-GdNP offers a high signal-to-background ratio (SBR = 86.2 +/- 12.0) to sensitively report on the increased hepatic H2S level in the acute hepatitis mice via afterglow imaging, which correlated well with the upregulated CSE activity in the liver, showcasing the good potential of F1-GdNP for monitoring of acute hepatitis process in vivo.