Cost-effective and portable electrochemical sensing of sweat constituents via printed electrodes

The integration of electrochemical sensing with printing technologies has opened new avenues for non-invasive, real-time monitoring of physiological biomarkers, particularly in the context of physical exercise. This review critically examines recent advances in cost-effective, portable, and wearable electrochemical sensor platforms designed to analyze exercise-induced biomarkers in human sweat. Emphasis is placed on the fabrication of flexible and disposable sensors using screen-printing, inkjet printing, and 3D printing, each offering unique advantages in terms of scalability, resolution, and substrate compatibility. These sensors target a wide spectrum of analytes—including metabolites, hormones, and electrolytes—each linked to crucial aspects of exercise physiology such as muscle fatigue, hydration, and stress. The review details strategies for enhancing sensitivity and specificity, such as enzyme immobilization, nanomaterial modification, and molecular imprinting. System-level integration with microfluidics and wireless electronics is also explored, highlighting innovations in sweat handling, real-time signal processing, and on-body validation. Despite significant technical progress, challenges persist in sensor calibration, stability, and physiological interpretation—particularly regarding the correlation between sweat and blood biomarker levels. Finally, the future of this technology is envisioned through the lens of emerging trends, including machine learning-based analytics, self-powered systems, and multi-analyte sensing platforms that promise to revolutionize personalized health monitoring and sports performance assessment.