Electroluminescence Biosensor for Determination of Pb2+Based on G-Quadruplex of Aptamer probe / 分析化学

ABSTRACT

A turn on model of electrochemiluminescence ( ECL)-Pb2+ biosensor based on G-quadruplex of aptamer probe was developed by using quantum dots ( QDs) as labels. The ECL-Pb2+ biosensor was prepared by immobilizing a hairpin aptamer probe with a thiol group at 5 '-end and an amino group at 3 '-end on gold electrode via an Au-S bond. In the presence of Pb2+, the G-rich hairpin aptamer probe opened the stem-loop and formed G-quadruplex, which exposed the amino group at 3'-end and then covalently linked to the carboxyl group on the surface of CdS quantum dots. The fabrication and reaction process of the Pb2+ biosensor were characterized. The responsive ECL intensity was linearly related to the Pb2+ concentration in the range of 2. 0×10-10-5. 0×10-8 mol/L, with the detection limit of 3. 74×10-11 mol/L. In addition, the ECL biosensor exhibited high sensitivity, good selectivity, satisfying stability, and repeatability.