Wash-less and highly sensitive assay for prostate specific antigen detection

A novel, simple and facile biosensor for prostate specific antigen (PSA) detection was constructed. In this method, proteolytically active PSA is capable of cleaving PSA substrate-magnetic carrier complexes. Electrochemical analysis of the sensor layer showed a significant decrease in impedance signal after proteolysis has occurred, whereas a positive change in impedance was observed using a negative control substrate, indicating the specificity of our detection mechanism. The biosensor has the ability to monitor PSA concentrations ranging from 1 pg ml(-1) to 1 mu g ml(-1) with a detection limit as low as 1 pg ml(-1). The sensor offers the possibility of developing a wash-less and cost-effective point-of-care device due to the simplicity of the probe immobilization process and the elimination of labeling and reporter molecules during the biosensing step.