Visualization of methylglyoxal in living cells and diabetic mice model with a 1,8-naphthalimide-based two-photon fluorescent probe.

Methylglyoxal (MGO), a dicarbonyl metabolite, is the most studied precursor of advanced glycation end-products (AGEs) and its elevated levels have also been associated with various pathologies. Hence, the development of effective methods for monitoring MGO in live cells and in vivo is of great importance for ascertaining the onset and progress of related diseases. Herein, we designed and synthesized an endoplasmic reticulum-targeting two-photon fluorescent probe called NI-OPD for the detection of MGO with high selectivity, sensitivity, and hypotoxicity. The probe was successfully applied for monitoring MGO in living cells and a diabetic mice model. The two-photon fluorescence images confirmed that the endogenous MGO in the liver and kidney tissues of diabetic mice is higher than that of normal mice. Furthermore, it revealed that after treatment with metformin, a widely used hypoglycemia drug, the diabetic mice showed a decreased concentration of MGO in liver and kidney tissues. Thus, NI-OPD may serve as a useful tool for the detection of MGO and for studying the relationships between MGO and pathological and biological processes in biosystems.