Near-Field Communication-Enabled Wearable Chemical Sensors for Bioanalytical Monitoring

This review evaluates the development and analytical potential of near-field communication (NFC)-enabled wearable chemical sensors for bioanalytical monitoring, including passive, battery-free, energy-buffered, and hybrid-energy architectures. Moving beyond conventional wireless data transmission, we emphasize how NFC-based power delivery and smartphone-interfaced readout interact with circuit design, flexible manufacturing, microfluidic biofluid handling, and target-specific interfacial chemistry. Representative applications in sweat, saliva, wound exudate, ocular fluids, and selected body-interfaced or portable point-of-care systems illustrate how sensing performance is governed by interfacial recognition and signal-transduction chemistry, together with sampling fidelity, reader coupling, calibration stability, and validation strategy. Although NFC-enabled sensors have achieved substantial miniaturization and functional integration, important limitations remain, including constrained power transfer, intermittent rather than truly continuous interrogation, calibration drift, biofouling, inter-device and smartphone-dependent variability, and limited real-world or clinical validation. Emerging directions such as hybrid energy harvesting, simplified analog readout, antifouling interfaces, and sensing-intervention integration offer promising opportunities, but their analytical robustness and translational relevance require rigorous assessment. Overall, this Review provides a chemical and analytical framework for evaluating NFC-enabled wearable sensing platforms and highlights the need for standardized validation before biofluid measurements are assigned clinical significance.