Electrochemical sensor array with nanoporous gold nanolayer and ceria@gold corona-nanocomposites enhancer integrated into microfluidic for simultaneous ultrasensitive lead ion detection

Abstract

To minimize the plumbic poisoning, the construction of powerful portable chip for ultrasensitive Pb2+ assay plays a significant role in clinical diagnosis and environmental monitoring. Herein, inspired by communicating vessels, a microfluidic electrochemical sensing chip array was proposed for ultrasensitive Pb2+ detection of multiple samples. An editable nanoporous gold nanolayer with a feature of all-round conductivity and abundant active sites favoring biological ligand attachment was employed as electrochemical sensing substrate. Ceria@gold corona-nanocomposites (CeO2@Au NPs) was designed and utilized as a differential pulse voltammetry response enhancer of the o-phenylenediamine-hydrogen peroxide electrochemical sensing system. In addition, the proposed chip contains ten detection units and no complex components (such as pump or valve), which makes it capable of processing multiple samples in batch for the in-situ detection with low cost. Under the optimized experimental conditions, the Pb2+ detection limit of 3.1 pM was achieved with good stability and reliability, which was benefited from the excellent sensing substrate and appropriate CeO2@Au NPs-trigger amplification strategy. The results indicated that the integration of novel microfluidic chip design and nanomaterials catalytic strategy provides a new paradigm for the field of in-situ analysis, and shows promise for potential applications in many analytic fields.