A Miniaturized Wireless Multimodal Physiological In-Vivo Monitoring Platform Featuring Power-Efficient Photoelectrochemical Sensing

The increasing diversity of sensing mechanisms has created a growing demand for compact and versatile readout platforms that can support multiple modalities under strict power constraints. Conventional photoelectrochemical (PEC) systems, in particular, rely on bulky optical setups and continuous high-power illumination, making them unsuitable for portable or in-vivo applications. To address these challenges, this work presents a miniaturized and reconfigurable sensing platform that integrates current, voltage, resistive and electrochemical measurement capabilities - along with an on-board current source for light-stimulated applications - within a 21 mm × 17 mm, 0.9 g hardware implementation. Compared with existing sensing systems, the proposed design achieves multimodal functionality, miniaturized implementation, and power-efficient operation within a fully integrated platform. To verify the system's multimodal capability, synchronous measurement experiments were conducted, demonstrating the ability to accurately capture signals across all sensing modalities while maintaining milliwatt power operation. Furthermore, a power-efficient PEC measurement method based on duty-cycled optical modulation is experimentally validated, demonstrating a feasible approach toward fully integrated, low-power PEC sensing suitable for wearable and in-vivo bioelectronic applications.