Adsorption of Anti-human IgG to Plasma-polymerized Allylamine Film Formed on a Silver Plate

Increase in the sensitivity of an immunosensor or bio-sensor requires the immobilization of a large amount of proteins. Good materials must be developed for this protein adsorption. Allylamine thin film was formed on a pat silver plate by plasma polymerization; this plate is referred to as Ag(ALAM).Ag(ALAM) films were characterized by SEM, FT-IR and ESCA. Investigations on adsorption and desorption of F(ab')(2) anti-human IgG (hlgG) on to Ag and Ag(ALAM) revealed the following: (1) The adsorption isotherm of F(ab')(2), anti-hIgG on to AG(ALAM) or Ag was of a Langmuir type. The binding constant (K-b) and saturation binding (A(b)) for this protein on to Ag(ALAM) were 8.93 l/mol and 181.8 nmol/m(2), respectively, and for Ag, were 7.71 l/mole and 87.9 nmol/m(2). (2) The extent of desorption of labeled F(ab')(2), anti-hIgG absorbed on the two plates was the same. (3) Ag(ALAM) and Ag were used as solid phases in a two-site immunoradiometric assay of human serum IgG. The dose-response on AG(ALAM) occurred at lower concentration, and was of greater magnitude than that on AS.