Microneedle-integrated sensors for dermal interstitial fluid extraction and real-time health monitoring

Abstract

Background The shift toward continuous health management has increased the need for minimally invasive diagnostics. Dermal interstitial fluid (ISF) is an attractive alternative to blood because its biomarker profile is similar, and it does not coagulate. However, conventional ISF collection remains invasive and inefficient. Microneedle (MN) technology addresses these limitations by painlessly penetrating the stratum corneum, enabling patient-friendly point-of-care testing and self-monitoring. Area covered This systematic review examines the physiological characteristics of ISF and the limitations of traditional extraction methods. It analyzes various MN materials (e.g., HA, PLGA, PVA) and structural designs, including solid, hollow, and hydrogel-forming MNs, optimized for efficient fluid sampling. It also describes the integration of MNs with advanced sensing modalities, focusing on mechanisms and recent trends in electrochemical, fluorescence, and immunodiagnostic sensor systems. Expert opinion Despite their potential, MN-integrated sensors face hurdles such as limited extraction volumes, material stability, and the physiological lag time between blood and ISF. Future research must focus on enhancing biomarker specificity and ensuring long-term sensing reliability. Overcoming these challenges will be essential for transitioning from laboratory prototypes to clinical-grade wearable devices that enable real-time, personalized health monitoring.