Covalent Immobilization of Antigen on Lithium Niobate Surfaces and Application of the Method in Detection of Immunochemical Reactions

摘要

covalent immobilization of antigen on lithium niobate (LiNbO_3) surfaces is studied. The immobilized films are characterized by X-ray photoelectron spectra (XPS) and enzyme-catalyzed kinetic spectrophotometry. An acoustic plate mode (APM) immunosensor is built by this method. In order to determine the binding capacity of antigens immobilized on lithium niobate surfaces, horseradish peroxidase (HRP) is used as antigen, and mouse-anti-horseradish peroxidase (anti-HRP) is used as antibody. The reaction of antigen with antibody is detected by the APM immunosensor. The results indicate that the density of the antigen film on the surface is 3.2X10~2ng /mm~2, and the anti-HRP concentration is correlated with the fractional changes in frequency, Δ f/f, in concentration range of 5 to 65μg /ml.