ENZYMATIC ELECTROCHEMICAL BIOSENSORS AND IMMUNOSENSORS

Abstract

Electrochemical biosensors have stood out as analytical devices for applications in health, environment, food industry and public safety, due to their sensitivity, selectivity and speed in the detection of specific analytes. These devices represent a viable and efficient alternative to traditional laboratory analysis methods, being able to provide real-time answers, at a lower cost and with greater portability. In this scenario, investing in research and development of biosensors is essential to meet the growing technological demands for early diagnosis, environmental monitoring, and industrial quality control. In addition, the integration of these devices with digital platforms and miniaturized systems expands their potential for application in remote environments. The objective of the chapter is to present the fundamentals, characteristics and applications of electrochemical biosensors, with emphasis on two main classes: enzymatic biosensors and immunosensors. Enzymatic biosensors are based on the immobilization of enzymes on electrodes, allowing the conversion of biological signals into measurable electrical signals. The specificity of enzymes due to their substrates ensures high selectivity in detection, being widely used for the quantification of glucose, lactose, urea and other relevant compounds in health and food. Enzyme immobilization can occur by different methods, such as adsorption, encapsulation, covalent bonding, and trapping in polymeric matrices. Advances in materials engineering have made it possible to improve the stability and efficiency of these devices, making them increasingly effective. Immunosensors, on the other hand, use the highly specific interaction between antigens and antibodies to recognize and quantify substances of interest, being especially useful in the detection of pathogens, tumor biomarkers, and pesticide residues. They can operate in different formats, such as direct or competitive immunoassay, with electrochemical detection based on the variation in current, potential, or impedance generated by the antigen-antibody binding. The appropriate choice of recognition elements and transducers directly influences the sensitivity, detection limit, and reproducibility of immunosensors. With the advancement of nanotechnology, these devices have become increasingly accurate, being able to operate at extremely low analyte concentrations. Thus, electrochemical biosensors represent strategic and innovative detection devices for rapid clinical diagnostics, precise environmental surveillance, and quality assurance in industrial processes and food products. Its continuous development is key to driving accessible and sustainable technological solutions, aligned with the emerging needs of contemporary society.

DOI: https://doi.org/10.56238/sevened2025.021-001