基于酶生物催化沉积放大的日本血吸虫压电免疫传感器

Piezoelectric Immunosensor Based on Enzyme-catalyzed Precipitation Amplification for Schistosoma-japonicum

提出了一种基于酶生物催化沉积放大的日本血吸虫压电免疫传感器．采用混合自组装单层膜技术在石英晶振金电极表面制备巯基丙酸（MPA）和巯基乙醇（ME）混合功能基底膜，通过偶联剂盐酸1-乙基-3-（3-甲基氨基丙基）碳二亚胺（EDC）及N-羟基琥珀酰亚胺（NHS）活化混合膜上富含的羧基基团用于日本血吸虫抗原（SjAG）的高效共价固定．通过夹心式免疫反应，将辣根过氧化酶（HRP）标记的羊抗兔二抗固定到晶体表面，利用HRP催化H202氧化底物4-氯-1-萘酚在晶振表面形成不溶性沉积物，使免疫检测信号得以显著放大．在优化的实验条件下，该传感器可灵敏检测感染兔血清样中日本血吸虫抗体（SjAb）浓度（稀释比）的线性范围是1：10000～1：100，可望用于日本血吸虫病的早期临床诊断．

A high sensitive piezoelectric immunosensor based on enzyme-biocatalyzed precipitation amplification was developed for the determination of schistosoma-japonicum antibodies （S jAb） in infected rabbit serum. The transducer substrate was first coated with mixed self-assembled monolayers of mercaptopropionic acid and mercaptoethanol for covalently immobilization of Schistosoma-japonicum antigens （S jAg）, which could specifically recognized SjAb. After the sandwich detection, horseradish peroxidase （HRP）-labeled goat-anti-rabbit antibodies were immobilized onto the substrate support. Subsequently, the frequency response of the SjAg-SjAb binding was greatly amplified by using the immobilized HRP to oxidize 4-chloro-l-naphthol in the presence of hydrogen peroxide to form an insoluble product on the crystal surface. Under optimized experimental conditions, the proposed immunosensor has proved to be capable of quantitatively determining SjAb in the concentration （di- lution ratio） range of 1 ： 10 000- 1 ： 100. This will be a promising alternative approach for schistosoma-japonicum in clinical diagnosis.