Historical Evolution of Electrodes and Their Impact on Electrochemical Sensing and Biosensing

This review outlines the historical development of electrodes and their importance in electrochemical sensing and biosensing. Electrode design and material choice directly influence sensitivity, selectivity, and applicability. Early systems such as mercury-based dropping mercury electrodes (DMEs) provided reproducible surfaces and broad potential windows, although their toxicity and environmental concerns restricted widespread use. The shift to solid electrodes including glassy carbon, carbon paste, and noble metals brought higher stability, conductivity, and simpler modification, which expanded sensing applications. Subsequent advances such as screen-printed and pencil graphite electrodes introduced low-cost, disposable formats that made electrochemical sensing more portable and accessible. More recently, flexible substrates, 3D-printed devices, and nanostructured materials have created opportunities for wearable technologies, real-time monitoring, and ultra-sensitive detection. Alongside these material innovations, this review examines current gaps related to scalability, commercialization, and sustainability, where translation from laboratory research to practical devices remains limited. The growing role of artificial intelligence (AI), machine learning (ML), and the Internet of Things (IoT) in optimizing electrode design, enabling large-scale data analysis, and supporting remote monitoring is also discussed. By combining historical insights with present challenges, this review outlines future directions toward reliable, safe, and widely accessible electrochemical sensing technologies.