A Multifunctional Capacitive Sensing Platform for Wireless Vascular and Heart Monitoring 

We present a multifunctional, antenna-integrated capacitive sensing (MAiCaS) platform for passive, wireless, and real-time cardiovascular monitoring. Unlike conventional systems that require separate sensors and wireless modules, our device unifies sensing, telemetry, and mechanical functionality into a compact and scalable design by exploiting the parasitic capacitance of an inductive antenna as a strain-sensitive element. The sensor is fabricated using a cleanroom-free, single-step UV laser patterning process on a flexible PDMS substrate, significantly reducing manufacturing complexity and enabling high reproducibility. The MAiCaS is suitable for three different applications: as a sensor for epicardial strain measurement, as a stent sensor, and as a vascular graft sensor. In vitro experiments demonstrated consistent resonance frequency shifts under physiological and patophysiological conditions, with stable performance observed on skin, in PBS, human serum, and simulated vascular environments. Calibration curves revealed high sensitivity across all configurations. The sensitivity of the device was measured to be 2.9 MHz per 1% strain, 0.43 MHz/mmHg, and 309.6 kHz/µm for applications of epicardial patch, graft, and stent integrated sensor, respectively. Furthermore, the operation of MAiCaS was evaluated in a human experiment using the unrolled format attached to the skin surface over the proximal interphalangeal joint. This monolithic sensor architecture provides a scalable and cost-effective solution for battery-free monitoring of heart and vascular dynamics.