Bamboo-inspired variable-modulus pressure sensors for dynamic plantar pressure mapping and gait monitoring

Abstract

Flexible pressure sensors are highly important for real-time plantar pressure monitoring, which supports gait analysis, foot disorder diagnosis, rehabilitation, and an improved understanding of human locomotion. However, the development of flexible pressure sensors capable of simultaneously achieving high sensitivity and a wide detection range remains a significant challenge. Inspired by the hierarchical porous structure of bamboo, which exhibits exceptional mechanical adaptability, we report a biomimetic variable-modulus pressure sensor (BVMPS). The sensor is fabricated by embedding multi-walled carbon nanotubes into a polydimethylsiloxane foam featuring a variable-modulus macro/microporous structure. This bioinspired structural design effectively balances the conflicting requirements of sensitivity and a wide response range.The optimized BVMPS demonstrates a high sensitivity of 553 kPa⁻¹, a broad detection range up to 1270 kPa, and long-term stability over 11,000 cycles. Furthermore, a 32-node smart insole array based on BVMPS sensing units was constructed for real-time plantar pressure monitoring and reliable gait phase identification during walking, stair ascent, and stair descent. This work provides a promising paradigm for bioinspired structural design in next-generation flexible electronics for healthcare and rehabilitation applications.