Bioinspired heliconical auxetic biofibers for intelligent biomechanical surveillance

Wearable bio-based fibers are emerging as platforms for biomechanical sensing and physiological interaction. However, achieving high sensitivity to subtle mechanical cues while maintaining flexibility, self-powered output, and distributed perception remains challenging. Inspired by the helical twining mechanics of climbing plant stems, we design a mechano-adaptive auxetic electronic bio-based fiber as an embodied intelligence sensing unit. The dual-modulus helical confinement, achieved by wrapping rigid aramid fiber/polydimethylsiloxane helices around a flexible collagen aggregate/waterborne polyurethane core, enables programmable deformation and a stable negative Poisson's ratio (ν = -0.47). Nonlinear intercomponent coupling facilitates synergistic axial-radial dynamics, amplifying interfacial contact variation under strain. The optimized fiber exhibits ultrahigh sensitivity (strain factor: 11.75), strong electrical output (8.1 volts), and remarkable power density (8.48 milliwatts per square meter) with excellent cyclic stability. Integrated into fiber-sensing arrays, it decodes microstrain patterns linked to lower-limb function, offering a scalable strategy for self-powered, adaptive, and durable biomechanical monitoring.