Volume 6, Issue 2 (2026) – 24 articles
Cover Picture: Heat accumulation from Joule heating and solar irradiation severely challenges thermal safety and signal stability of long-term, outdoor on-skin electronics and human-machine interfaces. Here, we develop a self-stratified stretchable passive cooling interface (SPCI) that implements a synergistic internal-dissipation and external-blocking strategy by inducing gradient stratification via the density mismatch between Al2O3 microparticles and liquid metal (LM) within the elastomer. This mismatch triggers spontaneous self-stratification upon curing, yielding a multi-layer composite that features an Al2O3-enriched top layer for high solar reflectance (92.6%) and an LM-network-enriched bottom layer for efficient heat dissipation (thermal conductivity ≈ 1.5 W·m-1·K-1), while retaining soft mechanics (elastic modulus ≈ 0.082 MPa) and high stretchability (> 800% elongation). The SPCI exhibits excellent cooling performance in serpentine circuits at 200 mW, reducing peak temperature by up to 8.4 °C indoors and 12 °C outdoors under solar exposure, while maintaining effective cooling under tension. When integrated into a wireless skin-interfaced photoplethysmography platform for heart-rate monitoring, it lowers the maximum surface temperature by 8.6 °C during outdoor operation, enabling superior preservation of pulse-wave features compared with conventional elastomer encapsulation. This work establishes a scalable, mechanically compliant encapsulation interface for simultaneously mitigating internal and external thermal loads in wearable electronics and human-machine interfaces.
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Back Cover Picture: Peripheral nerve injury often leads to severe and persistent motor and sensory deficits, thereby markedly reducing quality of life. Peripheral nerve interfaces offer opportunities to facilitate functional restoration by interrogating neural activity and delivering electrical therapy. However, existing devices are typically not designed for long-term monitoring of injured nerves and are fabricated from non-degradable materials that require surgical removal. Here we present a temporally biosynchronized, physically transient and flexible peripheral nerve interface that enables stable monitoring of neural activity throughout the post-injury recovery process. Integrated with machine-learning-based decoding, the interface achieves excellent motor intention recognition using peripheral nerve signals in a rodent sciatic nerve injury model, outperforming signals recorded from the primary motor cortex. Moreover, the device enables continuous tracking of nerve regeneration and supports bidirectional signal transmission, providing a foundation for closed-loop rehabilitation. This work establishes a transient and biomimetic peripheral nerve interface with the potential to advance neuroregeneration monitoring and adaptive neurorehabilitation strategies.
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