Electrochemiluminescence Aptasensor for Charged Targets through the Direct Regulation of Charge Density in Microchannels

The change of surface charge density can cause many changes in physical or chemical properties and has been applied to design many sensitive sensors. Ochratoxin A (OTA) is a negatively charged target in neutral or alkaline solutions. In this work, a microchannel-based electrochemiluminescence (ECL) aptasensor for OTA detection based on this character had been designed. The charged target directly combined with functionalization layers of the microchannels, which caused surface charge density variation and therefore resulted in the change of ECL intensity of the (1,10-phenanthroline)ruthenium(II)/tripropylamine system. The decrease of ECL intensity is linearly dependent on OTA concentration ranging from 0.5 to 4 ng mL-1 with a detection limit down to 0.17 ng mL-1. This strategy has the advantages of simple interface chemistry design and universality, which offers a guiding significance for the charged target assay.