一种基于聚集诱导发光机制的新型氨肽酶N荧光探针

A New Fluorescent Probe of Aminopeptidase N Based on Aggregation-Induced Emission Mechanism

氨肽酶N(APN)在人体中广泛存在,在肿瘤细胞表面大量表达,并在癌症侵袭、转移和血管生产过程中具有重要作用;体液中的APN可作为炎症、癌症的早期生物标志物.鉴于此,发展高灵敏度、高选择性的检测手段对APN进行实时检测及可视化成像将为APN相关疾病的诊断及病理生理学说明提供可能性.荧光探针因其选择性好、灵敏度高的优势,近年来已被广泛应用于生物酶检测.然而已报道用于检测APN的荧光探针多基于平面分子,易受聚集荧光猝灭(ACQ)限制.与基于传统平面分子的ACQ荧光染料相比,具有聚集诱导发光(AIE)效应的荧光分子能更好地应用于高浓度与高含水量的检测环境,为荧光探针技术的发展开辟了新的路径,而基于AIE机制的APN荧光探针仍鲜有报道.喹啉-丙二腈(QM)类化合物具有长发射波长,且生物相容性好、光稳定性优异,目前已有多种基于QM母体的AIE探针应用于细胞成像与各种活性物质检测.基于此,设计合成了以QM为母体的AIE荧光探针QM-Ala,探针具有99 nm的大斯托克斯位移、良好的稳定性、抗干扰能力和较快的响应速度,检测限(LOD)低至1.22 ng/mL.QM-Ala在3~7区间对pH有即时响应,并在体液pH条件下对APN质量浓度有良好的线性响应,因此有望应用于酶抑制剂筛选以及体液中的APN质量浓度检测.

Aminopeptidase N(APN)is widely present in the human body and highly expressed on the surface of tumor cells,playing an important role in cancer invasion,metastasis,and angiogenesis.APN in body fluids can serve as an early biomarker for inflammation and cancer.Thus,the development of highly sensitive and selective detection methods for real-time monitoring and visualization of APN can provide possibilities for diagnosis and pathophysiology of APN-related diseases.Although fluorescent probes have been widely applied in enzymatic detection in recent years due to their advantages of good selectivity and high sensitivity,the ones reported for APN detection are mostly based on planar molecules,which are susceptible to aggregation-caused quenching(ACQ).Compared with traditional planar ACQ fluorophores,fluorescent molecules with an aggregation-induced emission(AIE)effect can be more effectively applied in high-concentration and high-water-content detection environments.This can aid in the development of a new strategy for the fluorescence probe technology.However,APN fluorescent probes based on the AIE mechanism have rarely been reported.Quinoline-malononitrile(QM)compounds have long emission wave lengths,outstanding biocompatibility,and remarkable photostability. Several AIE probes based on the QM structure have been applied in cell imaging and detection of various active substances. Thus,we designed and synthesized a QM-based AIE fluorescent probe,QM-Ala. This probe had a large Stokes shift of 99nm,outstanding stability, anti-interference ability,and a relatively fast response rate with a limit of detection of 1.22 ng/mL. QM-Ala exhibited an immediate response to pH in the range of 3-7 and an outstanding linear response to APN mass concentration in body fluid pH conditions. Thus,it has the potential to be applied in enzyme inhibitor screening and APN mass con-centration detection in body fluids.