Lipases are acyl hydrolases that play a key role in fat digestion and monitoring of acute pancreatitis by cleaving long-chain triglycerides into polar lipids. Due to an opposite polarity between the hydrophilic enzyme and their lipophilic substrates, lipase reaction occurs at the interface between the aqueous and the oil phases. It is quite challenging to develop a specific probe to detect lipase activity, especially in homogeneous systems. Herein we designed a blue fluorescent probe HBT-LDC for specific detection of lipase activity based on both aggregation induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) effect. The probe shows significant advantages, such as high selectivity and excellent sensitivity, no self-quenching at high concentration, large Stokes shift, low cytotoxicity, and good biocompatibility. The linear range for in vitro quantification of lipase is 0.2–1.3 mg/mL with a detection limit of 0.01 mg/mL. The probe has been successfully applied to the evaluation of commercial lipase and the in vivo bioimaging sensing exogenous lipase activity in HeLa cells. The results revealed that the probe could serve as a potential tool in lipase related drug discovery and disease diagnostics.

脂肪酶是酰基水解酶，通过将长链甘油三酯切割成极性脂质，在脂肪消化和监测急性胰腺炎中起关键作用。由于亲水性酶与其亲脂性底物之间的极性相反，脂肪酶反应发生在水相和油相之间的界面。开发一种特异性探针来检测脂肪酶活性非常具有挑战性，尤其是在均质系统中。在此，我们设计了一种蓝色荧光探针 HBT-LDC，用于基于聚集诱导发射 (AIE) 和激发态分子内质子转移 (ESIPT) 效应特异性检测脂肪酶活性。该探针具有选择性高、灵敏度高、高浓度不自猝灭、斯托克斯位移大、细胞毒性低、生物相容性好等显着优点。脂肪酶体外定量的线性范围为 0.2–1.3 mg/mL，检测限为 0.01 mg/mL。该探针已成功应用于商业脂肪酶的评估和HeLa细胞中外源性脂肪酶活性的体内生物成像检测。结果表明，该探针可以作为脂肪酶相关药物发现和疾病诊断的潜在工具。