Untangling the Janus Effects of Ligament Size in Metal Aerogels for Wearable Electrochemical Biosensing

Abstract Wearable electrochemical biointerfaces require electrode architectures that reconcile high electrochemical activity and mechanical flexibility, yet the micro-/nanoscale origin of this trade-off remains unclear. Here, ligament size-tailored gold aerogels are employed as a model system to how microstructural scaling governs their coupled electrochemical-mechanical behavior. Smaller ligament sizes increase surface area, accelerate charge transfer, and enhance bioelectrocatalytic activity, but they promote fracture and signal degradation under repeated deformation. In contrast, larger ligaments better preserve network continuity and conductive pathways at the expense of sensitivity. In situ scanning electron microscopy combined with molecular dynamics simulations identifies the diameter-dependent fracture strain of nanowires as a key descriptor linking nanoscale mechanics to macroscopic electrode stability. Guided by this mechanistic relationship, an intermediate ligament size achieves an optimal electrochemical activity-mechanical resilience balance, enabling deformation-stable sweat glucose monitoring with microfluidic sampling and wireless readout. This work offers a structural design guideline for high-performance wearable biosensing systems.