Electrochemical Impedance Spectroscopy biosensor for antigen-antibody detection

Abstract

Having an early diagnostic method would be beneficial to prevent autoimmune diseases from worsening. This is where Electrochemical Impedance Spectroscopy (EIS) biosensors become more promising in healthcare applications due to their ability to perform label-free measurements. Labels are, for example, enzymes attached to antigens. This will lead to a cost reduction and decrease in detection time of specific biomolecules. In addition, EIS can be applied in many other areas, including but not limited to: electrode redox reactions, power source applications, corrosion, and self-assembled monolayers. The aim of this paper is to assess whether it is possible to detect antigen-antibody interactions using an EIS biosensor. This was tested by optimizing an existing ELISA protocol. This protocol is based on studying the detection of Sperm-associated antigen 16 (SPAG16) with anti-SPAG16 antibody interactions. The experiments were performed on commercially available EIS biosensors as a proof of principle. Our results show that the EIS sensor can successfully detect SPAG-Thio antigen-antiSPAG antibody interactions. Currently, this sensor has a limit of detection of100 pg/mL. However, non-specific interactions maintain a limitation of the sensor. It can be concluded that further research is required to reduce the non-specific interactions. This will result in a more optimized antigen-antibody detection. This is how we proved our proof of principle, which can be tested on homemade EIS sensors in a follow-up study.