- Electrochemical immunoassays are a class of biosensing techniques that combine the specificity of immunoassays with the sensitivity and simplicity of electrochemical detection methods. These assays are designed to detect and quantify biomolecules—such as proteins, hormones, pathogens, or antibodies—by exploiting antigen-antibody interactions and translating the resulting binding events into measurable electrical signals.
- In a typical electrochemical immunoassay, a specific antibody or antigen is immobilized on the surface of an electrode. When the target analyte is introduced, it binds to the immobilized counterpart, forming a stable complex. This interaction can be detected through various electrochemical techniques, such as amperometry, voltammetry, potentiometry, or impedance spectroscopy, depending on the assay design. The signal generated is proportional to the concentration of the analyte, allowing for accurate and sensitive quantification.
- To enhance sensitivity, many electrochemical immunoassays incorporate labels such as enzymes (e.g., horseradish peroxidase or alkaline phosphatase), redox-active compounds, or nanoparticles that produce or amplify electrical signals. These labels catalyze reactions that generate measurable currents or changes in potential at the electrode surface. Some formats, like label-free electrochemical immunosensors, detect the changes in the electrical properties of the interface directly upon antigen-antibody binding, offering a simpler and faster alternative.
- Electrochemical immunoassays are widely used in medical diagnostics, environmental monitoring, and food safety due to their low cost, portability, rapid response, and potential for miniaturization and automation. They are especially suitable for point-of-care testing and in-field applications, where fast and reliable results are needed without sophisticated instrumentation. As advancements in nanotechnology and microfabrication continue, electrochemical immunoassays are becoming increasingly sensitive, selective, and versatile, paving the way for next-generation biosensing platforms.
