ANTIBODY-BINDING TO A FUNCTIONALIZED SUPPORTED LIPID LAYER - A DIRECTACOUSTIC IMMUNOSENSOR

A direct immunosensor has been developed using an acoustic wave device as a transducer. The device is based on an acoustic waveguide geometr y that supports a Love wave, The biorecognition surface, formed on a g old layer, consisted of a biotinylated supported lipid layer which spe cifically bound streptavidin and, subsequently, biotinylated goat IgG, The modified surface was used as a model immunosensor and successfull y detected rabbit anti-goat IgG in the concentration range 3 x 10(-8)- 10(-6) M, Using the anti-goat IgG binding isotherm and the time-resolv ed measurements of antibody binding, both the binding and rate constan ts of the reaction were determined, The specificity of each binding st ep was studied with the acoustic wave device, and it was concluded tha t the phospholipid bilayer showed a good suppression of nonspecific bi nding, Comparative measurements using surface plasmon resonance allowe d the response of the immunosensor to be quantitatively correlated wit h mass binding to the surface.