Aptamer-Functionalized Au Nanoparticles for the Electrochemical Detection of Thrombin

An aptamer-based sandwich assay with electrochemical detection for thrombin analysis is reported using Au nanoparticles. The primary aptamer was immobilized on the surface of a screen-printed carbon electrode (SPCE) and the secondary aptamer was immobilized on Au nanoparticles. The electrochemical reduction current response of Au nanoparticles was monitored for the quantitative detection of thrombin. The limit of detection was determined as 1 nM. The proposed work demonstrates the high specificity of aptamers together with the use of Au nanoparticles. The effect of interfering proteins such as bovine serum albumin (BSA) was investigated. Control experiments also involved the use of an aptamer that has a binding affinity to immunoglobulin E (IgE). Aptamer-based analysis using Au nanoparticles opens the possibility of applications in complex biological fluids and a step closer towards diagnostics or medical investigation.