Prostate-specific antigen detection by using a reusable amperometric immunosensor based on reversible binding and leasing of HRP-anti-PSA from phenylboronic acid modified electrode

Background: In recent years. many automated immunoassay analyzers have been developed for accurate diagnosis of various disease states and to improve effective drug administration. Amperometric immunoassay has been increasingly applied to laboratory medicine due to its ease in automation, rapid speed and low detection limits. It is important to develop reusable immunologically-sensitive elements for prostate-specific antigen (PSA) detection. Methods: The strategy for the immunosensor construction is based on the enzyme-conjugated prostate-specific antibody (HRP-anti-PSA) reversible binding with a self-assembled phenylboronic acid monolayer on gold. Results: After incubating an HRP-anti-PSA modified electrode in a PSA solution. a decrease in the electrocatalytic response of the HRP-anti-PSA modified electrode to the reduction of H2O2 is observed. The photometric activity assays show that this decrease of the electrocatalytic response arises from the formation of immunocomplexes of HRP-conjugated anti-PSA and its antigen, not from the loss of bound HRP-anti-PSA from the electrode surface. Analytical performances and optimal conditions of the described immunosensor are also investigated. Under the optimal conditions, the amperometric immunosensor shows a linear increase of the relative intensity in 2 PSA concentration range from 2 to 15 ng/ml and 15 to 120 ng/ml, respectively. Conclusion: This method could be used for rapid analysis of PSA and potentially other antigens. (C) 2008 Elsevier B.V. All rights reserved.