Nuclear-targeted chiral red-emissive carbon dots for visual detection of leucine aminopeptidase in vitro.

Leucine aminopeptidase (LAP) is a key biomarker for the early diagnosis of drug-induced liver injury (DILI). Traditional detection methods are difficult to meet the actual needs of clinical dynamic monitoring due to problems such as poor selectivity and low sensitivity. To solve this problem, a nuclear targeted dual mode sensor was developed for the sensitive and selective detection of LAP activity on the basis of red emission chiral carbon dots (R-L-CDs). During the sensing process, LAP catalyzed L-leucine p-nitroaniline (L-Leu-pNA) hydrolysis to product pNA, which had an obvious absorption in the visible region, leading to fluorescence quenching. The fluorescence and colorimetric signals of R-L-CDs could specifically detect LAP with detection limits of 0.17 U/L and 0.69 U/L, which were lower than those of previously reported sensors. Importantly, the sensor could not only detect LAP in living cells, but also verify the pathway of generation and repair of APAP-induced hepatotoxicity. Moreover, the color change could be rapidly captured and quantified using a smartphone equipped with a RGB detection mode. Therefore, R-L-CDs as a sensitive dual mode sensor not only provided an effective approach for the detection of LAP activity, but also paved the way for clinical diagnosis of DILI.