Sarkar, P.Ghosh, D.Bhattacharyay, D.Setford, S. J.Turner, Anthony P. F.2009-06-122009-06-122008P. Sarkar , D. Ghosh , D. Bhattacharyay , S. J. Setford , A. P. F. Turner, Electrochemical Immunoassay for Free Prostate Specific Antigen (f-PSA) Using Magnetic Beads, Electroanalysis, 2008, Volume 20, Issue 13, Pages 1414 to 14261521-4109'http://dx.doi.org/10.1002/elan.200804194http://hdl.handle.net/1826/3451Prostate specific antigen (PSA) is a prominent marker for the prostate carcinoma. It is found in human blood in free (f-PSA) and complex forms. These two forms together are called total PSA (t-PSA). Estimation of both forms is essential to predict malignancy. In this study we report a unique and effective technique of electrochemical detection of f-PSA using magnetic beads on a three-electrode screen-printed sensor. A magnetic bead enzyme linked immunosorbent assay (ELISA) was performed in a cuvette. Following the immunoassay, magnetic beads were recovered by a magnetic concentrator and transferred on the working electrode of the 3-electrode assembly. The amperometric response, a measure of the amount of residual enzyme activity on the beads and hence the concentration of analyte in solution, was determined by addition of enzyme substrate. The device has a detection limit of <0.1 ng mL-1 f-PSA and a linear range of 0 to 1 ng mL-1 f-PSA.enBioanalytical methodsBioassaysBiosensorsImmunoassaysELISAPostprint