Electrochemical detection of human Immunoglobulin-G using Gold Nanowires Immunosensor

Nowadays the demand for new devices capable of accurate, fast, and in situ real-time analyses is growing rapidly in the medical field. In this work, a high sensitivity electrochemical immunosensor based on gold nanowires was developed for the detection of a model protein. Immunoglobulin-G accounts for about 75% of serum antibodies in humans, and it is the most common type of antibody found in the bloodstream. Therefore, it represents a perfect model for the development of immunosensors for biomarker detection. Gold nanowires were fabricated by electrochemical template deposition. Then, a sandwich configuration was assembled on the electrode surface. The sandwich configuration consists of a primary antibody attached to the electrode surface, an antigen to be detected, and a secondary labelled antibody. The immunosensor is electrochemically active thanks to the gold nanoparticles tagging the secondary antibody. Given that, gold nanoparticles catalyse the hydrogen evolution reaction, the chronoamperometric technique was used for the detection. Because of the nanostructures high surface area and the catalytic properties of gold nanoparticles, an immunosensor with high sensitivity was obtained.