A novel approach of antibody immobilization based on n-butyl amine plasma-polymerized films for immunosensors

A novel method based on plasma-polymerized films (PPFs) is proposed for immobilizing antibodies (antigens) through a polyelectrolyte-mediated layer. The immobilization of goat-anti-IgG antibody, as an example, is investigated. The n-butyl amine PPFs are deposited on the surfaces of quartz crystal microbalance (QCM) with a radio frequency plasma method using n-butyl amine as the precursor, the IR spectrum indicating the existence of amino-groups in the film. After self-assembling a polystyrenesulfonate (PSS) layer on the PPF, the goat-anti-IgG antibody is immobilized in a 0.2 mg ml(-1) of antibody immobilizing solution at pH 5.0. The QCM immunosensor can quantitatively determine NH IgG in the range of 0.7-126 mu g ml(-1). Moreover, the PSS and protein layers can easily be removed simply by shifting the pH, making the immunosensor regenerable. (C) 2000 Elsevier Science B.V. All rights reserved.