Wireless hydrogel microneedle-enabled photonic sensing platform for continuous in situ monitoring of wound-bed oxygen...

Continuous monitoring of wound-bed oxygenation provides important insight into healing progression and therapeutic response. Optical sensing offers a highly attractive route and remains challenging due to impaired light transport, limited signal collection, and unstable device-tissue coupling in wound environments. Here, we present a wireless hydrogel microneedle-enabled photonic sensing platform (MN-PS patch) for continuous, in situ monitoring of wound oxygen dynamics. Oxygen-responsive polymer-dot (Pdot) nanoprobes are embedded within a transparent hydrogel microneedle array, where a semiconducting polymer donor transfers energy to an oxygen-sensitive metalloporphyrin acceptor, enabling ratiometric luminescence-based oxygen readout. The microneedle architecture establishes a minimally invasive and conformal interface while creating transparent optical channels that enhance excitation delivery and emission collection. The MN-PS patch exhibits a linear ratiometric response to physiologically relevant oxygen concentrations (10-100 μM) and enables wireless optical readout using smartphone imaging. In a murine wound model, the platform continuously resolved hypoxia-reoxygenation dynamics during healing and quantitatively captured therapeutic responses to a ROS-scavenging and oxygen-generating SOD/CAT treatment. These results demonstrate that wound-bed oxygen dynamics can serve as a functional biomarker of healing progression. The MN-PS platform provides a minimally invasive strategy for real-time microenvironment monitoring and offers a general approach for photonic biosensing in dynamic soft-tissue environments.