Label-free Electrochemical Immunosensors for Viruses and Antibodies Detection-Review

This article reviews the electrochemical immunosensors developed by the successive modification of gold as well as glassy carbon electrodes. Antibody or antigen fragments have been applied as the sensing elements. The complex between virions and specific antibody adsorbing on a surface of an electrode forms an insulating layer. This phenomenon, which is a base of ion – channel mimetic type of immunosensors, can be monitored by Osteryoung square-wave voltammetry (OSWV) and electrochemical impedance spectroscopy (EIS) in the presence of [Fe(CN)6] as a redox marker. Another type of immunosensors are based on redox active layers incorporated di-pyrromethene -Cu(II) or phenanthroline – Epoxy Fe(III) complexes. Changes of electrochemical parameters of redox centres upon target analyte binding are the basis of analytical signal generation. Both type of immunosensors displayed better sensitivity in comparison to ELISA as well as being very selective. The matrix has no influence on the immunosensors performance. These devices could be recommended for the direct electrochemical detection of viruses as well as antibodies in physiological samples.