▎ 摘　　要

Phospholipase A(2) (PLA(2)) enzyme could be acted as a unique biomarker for forecasting and diagnosing certain diseases. Therefore, it is important to monitor PLA(2) activity in biological and clinical samples. In this work, a simple electrochemical assay for PLA(2) activity was developed based on a screen-printed carbon electrode (SPCE) with 3D graphene-like surface. When the PLA(2)-containing sample was mixed with the nanoprobes, i.e. the electroactive marker methylene blue (MB) encapsulated within nanometer-sized phospholipid liposomes, MB was released and adsorbed/enriched in site onto the surface of SPCE in a micro-cell. The encapsulation and enzymatic release of MB were evaluated using UV-Vis and fluorescence. The peak current due to oxidation of the adsorbed MB on the SPCE was measured by square-wave voltammetry (SWV). The current was directly linear to the PLA(2) activity from 5 U/L to 200 U/L with a detection limit of 3 U/L. The same method can also be used for screening PLA(2) inhibitors. Thus, the enrichment strategy developed in this work could be a promising signal amplification method for the sensitive and selective detection of PLA(2) in biological or clinical samples.