Electrochemical immunoassay for CD10 antigen using scanning electrochemical microscopy

In the present study, a scanning electrochemical microscopic (SECM) method for imaging of antigen/antibody binding was proposed using CD10 antigen as the model. On the basis of anti-CD10 modified electrode, an electrochemical immunosensor for sensitive detection of CD10 antigen at low potential was developed by a multiple signal amplification strategy. Gold nanoparticles (AuNPs) served as carriers to load more secondary antibodies (Ab(2)) and horseradish peroxidase (HRP). The tip ultra-microelectrode was used to monitor the reduction current, and the 3-D images were obtained simultaneously. Under optimized conditions, the approach provided a linear response range from 1.0 x 10(-11) to 6.0 x10(-11) M with a detection limit of 4.38 x 10(-12) M. SECM is a versatile system that can be used not only for quantitative current analysis but also for topographic imaging of binding reaction. In addition, specific binding of antigen-antibody could also be continuously and successfully monitored by SECM. This immunoassay provides a sensitive approach for detecting tumor marker, and has potential application in clinical diagnostics. (C) 2012 Elsevier B.V. All rights reserved.