A Boundary Reshaped Biosensor with an Axon‐Like Microstructure for Diabetes Care Monitoring

ABSTRACT Continuous blood glucose monitoring can greatly reduce the risk of serious complications from diabetes. However, most biosensors suffer from two‐dimensional (2D) stacking of sensing coatings and interfacial charge accumulation, significantly impeding the efficient transfer of electrons in the electrodes. Inspired by the ability of myelinated axons to accelerate electrical signal conduction, a biosensor in the microneedle that can breach the 2D “dead” domain and mimic the microstructure of axons is developed. Controlled electrodeposition of Prussian blue (PB) on the carbon nanotube network transformed the 2D structure of sensing units into a homogeneous 3D triple‐phase boundary (TPB), improving PB utilization and catalytic activity. Through the crystallization and elution of a saturated salt solution, the nano nodes, similar to nodes of Ranvier, are formed within the enzyme layer, reducing charge accumulation and creating an electron‐transport “hyperchannel” that accelerated electron transfer by ∼60 times. The integrated microneedle sensor achieved high accuracy and full coverage of the sensing range for physiological conditions with 12‐month room‐temperature storage stability. Furthermore, the 3D structural system can effectively collect electromyography (EMG) signals, which may assist in determining muscle dysfunction in diabetic patients.