A benzotriazole-coumarin derivative as a turn-on fluorescent probe for highly efficient and selective detection of homocysteine and its bioimaging application

Abstract

Biological thiols such as cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) play essential roles in physiological and pathological processes, abnormal concentration of biothiols could lead to various diseases. Due to the structure similarity, it’s difficult to design fluorescence probes to selectively detect the common biothiols. Herein, a series of fluorescent molecules based on benzotriazole and coumarin moieties were designed and synthesized. Among these molecules, (E)-3-(2-(1H-benzo[d][1–3]triazol-1-yl)vinyl)-4-chloro-7-(diethylamino)–2H-chromen-2-one (BTAC (e)) exhibits high selectivity towards Hcy. When different biothiols were introduced, the probe BTAC(e) could react with Hcy by a thiol-halogen SNAr nucleophilic substitution-rearrangement reaction and exhibited enhancement in fluorescence. With the introduction of benzotriazole, BTAC(e) could respond to Hcy more quickly. At the same time, this probe exhibited excellent selectivity towards Hcy, it turns out that Cys and GSH have little influence on the fluorescence of BTAC(e). Under the optimized conditions, the fluorescence intensity has a good linear relationship with the concentration of Hcy in the range of 2.0 × 10-7 to 7.0 × 10-6 mol L-1 and the limit of detection for Hcy is 1.55 × 10-8 mol L-1. Moreover, probe BTAC (e) has been applied for imaging Hcy in living cells and the experimental result is satisfactory.