Antibody immobilization on a nanoporous aluminum surface for immunosensor development

A method of antibody (Ab) immobilization on a nanoporous aluminum surface for an electrochemical immunosensor is presented. To achieve good attachment and stability of Ab on an aluminum surface, aluminum was silanized with 3-aminopropyltryethoxysilane (APTES), and then covalently cross-linked to self-assembled layers (SALs) of APTES. Both the APTES concentration and the silanization time affected the formation of APTES-SALs as Ab immobilization. The formation of APTES-SALs was confirmed using the water contact angle on the APTES-SALs surface. The reactivity of APTES-SALs with Ab was investigated by measuring the fluorescence intensity of fluorescein isothiocyanate-labeled Ab-immobilized on the aluminum surface. Silanization of aluminum in 2% APTES for 4 h resulted in higher water contact angles and greater amounts of immobilized Ab than other APTES concentrations or silanization times. More Ab was immobilized on the nanoporous surface than on a planar aluminum surface. Electrochemical immunosensors developed on the nanoporous aluminum via the Ab immobilization method established in this study responded functionally to the antigen concentration in the diagnostic solution. (C) 2012 Elsevier B. V. All rights reserved.