Temperature-self-compensated hydrogel resonant sensor network for high-accuracy, multiplexed, and wireless wound monitoring

Inductance-capacitance (LC) resonators enable battery-free and wireless wound monitoring by using near-field inductive coupling to a reader coil to track resonance frequency shifts. However, a critical yet often overlooked limitation of existing LC wound sensors is that their resonance frequency is highly susceptible to temperature variation, because the dielectric media used in the capacitive region are temperature-sensitive. This temperature-induced drift significantly compromises measurement accuracy and may lead to erroneous interpretation of wound status. Here, we introduce a temperature-responsive resonance amplitude as an intrinsic parameter embedded within the raw spectral resonance, enabling in situ temperature readout for self-compensation of temperature-induced frequency drift without an additional temperature resonator. Specifically, a temperature-responsive resistive segment was integrated into the split-ring resonator, and the responsive hydrogel was positioned in a weak-field region to develop a temperature-self-compensated hydrogel resonant sensor (TC-HRS). Using 35 ℃ as the reference temperature, the temperature-induced error was reduced by 80–94% over the physiologically relevant range of 30–40 ℃. Furthermore, multiplexing was achieved by magnetically coupling three TC-HRS channels via an intermediate relay coil, thereby enabling simultaneous wireless readout of three wound-infection responsive proxies, evaluated here using MMP-9, glucose, and H₂O₂ as representative stimuli. The TC-HRS channels were integrated into a microfluidic Janus patch for in vivo proof-of-concept wireless readout, while unidirectional exudate management promotes healing. This work presents a promising proof-of-concept strategy for accurate, wireless, and multiplexed LC-based wound monitoring.