Impedimetric immunosensors for detection of biomarkers

Abstract

Immunosensing strategy is generally based on strong interactions between an antibody and an antigen. However, in an immunosensor system the antibody is frequently immobilized on a transducer element to detect the antigen opposite of this to develop an immunosensor. Immunosensors exhibit extremely sensitive and selective performance because of the extraordinary specificity to target ligands held by their biochemical nature. This makes them one of the most important and attractive candidates to develop biosensing strategies, especially for clinical applications. Moreover, immunosensors are vitally important for the detection of biomarkers, which are measurable biochemical indicators of important biological conditions. A biomarker often indicates a pathogenic process or pharmacologic response to medical intervention by the evaluation of their increasing or decreasing levels. Electrochemical impedance spectroscopy (EIS) is a powerful electrochemical technique used for the analysis of any biological compound of interest such as antibodies, nucleic acids, membrane receptors, etc. EIS is based on the charge transfer resistance occurring at any conductive surfaces. EIS explores measurements of the level of biochemical targets without using any molecular label. This chapter addresses the performance of EIS-based immunosensors on the determination of important biomarkers for diseases such as cancers, neurodegenerative, cardiovascular, or etc. Emphasis is given to the procedures that have been used for the immobilization of the bioreceptor of the immunosensor. Additionally, the fundamentals of the immunosensing strategy, analytical performances, and the success in the clinical applications to the real human samples are also discussed. © 2022 Elsevier Inc. All rights reserved.