Electrochemical Immunosensors Based on Gold Nanoparticles for the Determination of Ovalbumin in Immunobiological Preparations

A sandwich-type voltammetric immunosensor based on conjugates of gold nanoparticles (AuNP) with specific immunoglobulins (IgG) against ovalbumin (IgG@AuNP) is developed for the determination of ovalbumin in some immunobiological preparations. The IgG@AuNP conjugate is synthesized by passive adsorption. A carbon-containing planar printed electrode modified by laser reduced graphene oxide is used as a substrate electrode for immobilizing the receptor layer of specific immunoglobulins. A possibility of the catalytic reduction of silver nitrate with a mixture of reducing agents, citric acid and metol, is considered in order to enhance the signal of AuNP. Conditions for the voltammetric recording of the electrochemical signal of silver on an immunosensor, which has been successfully tested in determining ovalbumin residues in some immunobiological drugs, are selected. Enzyme-linked immunosorbent assay is used as a reference method.