A rapid and simple method for ultrasensitive electrochemical immunoassay of protein by an electric field-driven strategy.

A sensitive, rapid and simple method for analysis of protein was proposed by introducing an electric field-driven technique to the incubation process of immunoassay and immobilizing horseradish peroxidase (HRP) labeled antibody in a newly designed gel matrix to construct an immunosensor. With an electric field-driven technique, the incubation for immuno-recognition could be completed within 2 min. The immobilized HRP showed excellent direct electrochemistry in this new gel matrix, and the detection procedure was greatly simplified by directly monitoring the sensitive electrochemical signal of HRP upon the immunoreaction. Using alpha-fetoprotein as a model the linear detection range was from 0.02 to 2.0 ng mL(-1) with a detection limit down to 138 amol mL(-1). The immunosensor and the proposed detection method showed good specificity and acceptable stability and accuracy.