Rationally designed pure-inorganic upconversion nanoprobes for ultra-highly selective hydrogen sulfide imaging and elimination in vivo

Lung injury is a hydrogen sulfide (H(2)S)-associated complication with high mortality in acute pancreatitis (AP) cases. Herein, we used Prussian Blue (PB) as a H(2)S-responsive acceptor to develop a novel pure-inorganic upconversion nanoprobe for detecting and eliminating H(2)S, which can be used for diagnosing AP and alleviating lung injury. Upconversion nanoprobes with 5 nm PB shells were optimized to achieve outstanding in vitro H(2)S detection capacity (linear range: 0–150 μM, LOD: 50 nM), which met the in vivo serum H(2)S range, and thus were feasible for imaging H(2)S in vivo. More importantly, when combined with the traditional H(2)S synthetase inhibitor dl-PAG, the nanoprobes also served as a therapeutic agent that synergistically alleviated lung injury. As PB is an FDA-approved drug, our work proposes a potential clinical modality for the early diagnosis of AP, which will decrease lung injury-induced mortality and increase the survival rates of AP cases.