Wearable sweat induction strategies for noninvasive biosensing

Wearable sweat sensors have emerged as powerful tools for non-invasive and real-time health monitoring, offering insights into hydration status, electrolyte balance, metabolic activity, and disease biomarkers. Sweat induction is a foundational step in design of wearable sweat sensors, as it directly impact sensing reliability, particularly in scenarios where natural perspiration is insufficient or unavailable. This review provides a comprehensive overview of recent advances in sweat induction techniques, inclduing enhanced passive, iontophoretic, microneedle-assisted, and thermal-induced techniques for wearable sensing platforms. Each method is evaluated in terms of induction effciency, sweat rate, power consumption, invasiveness, and integration potential with flexible electronics. By comparing these approaches and highlighting their respective advantages and challenges, this review aims to guide the future design and optimization of next-generation wearable sweat induction systems for sweat sensing and and disease diagnosis.