[An ellipsometric study of the antigen-antibody interaction in the interphase solid/solution area]. / Ellipsometricheskoe izuchenie vzaimodeistvii antigen-antitelo v mezhfaznoi oblasti tverdoe telo/rastvor.

Ellipsometric studies have proved that monoclonal immunoglobulin G(IgG) against gamma-interferon (gamma-INF) and immunoglobulin fraction (Ig-fraction) of rabbit blood serum against human serum albumin (HSA) are adsorbed according to the Langmuir model on the surfaces of mirror plates of covalently modified gamma-INF or HSA, respectively. The maximum surface concentrations (Tmax) and equilibrium adsorption constants (K) for IgG and Ig-fraction are equal to 2.57 pmol/cm2 and 2 x 10(7) M-1, 3.3 mg/m2 and 0.1 cm3/micrograms, respectively. The additional treatment of gamma-INF modified surfaces with Tween-20 leads to an increase of K IgG ut to 2.7 x 10(-7) M-1 while Tmax decreases up to 1.12 pmol/cm2 which is conditioned by the blocking of protein non-specific binding sites. The role of specific and non-specific interactions of IgG and Ig-fraction with covalently immobilized antigens was studied at antibody-antigen mixture adsorption. The necessity to apply this method to quantitative determination of gamma-IHF and HSA in solutions was proved.

Ellipsometric immunosensors for the determination of gamma-interferon and human serum albumin.

Ellipsometric immunosensors for gamma-interferon (gamma-INF) and human serum albumin (HSA) have been developed using gamma-INF and HSA covalently immobilized onto silicon plates. Detection is achieved by measuring the adsorption decrease (gamma, mg m-2) of monoclonal immunoglobulin G against gamma-INF or immunoglobulin fraction of rabbit blood serum against HSA when the concentration of antigen in mixtures of antibody-antigen is increased. The time of analysis is 50 min, the detection limit of gamma-INF is 15 nM (sensitivity -0.01 mg m-2 nM-1) and of HSA 2.5 nM (-0.06 mg m-2 nM-1).