Ultralow Power, Cleft Size‐Adjustable and pH‐Sensitive Hyaluronic Acid (HA) Biodevices for Acid‐Sensing Ion Channels Emulation

Abstract The burgeoning implantable biodevices have unlocked new frontiers in healthcare, promising personalized monitoring strategies tailored to specific needs. Herein, hyaluronic acid (HA) is harnessed to create fully biocompatible, acidity‐sensitivity and cleft‐adjustable neuromorphic devices. These HA‐biodevices exhibit remarkable sensitivity to pH variations, effectively mimicking biological acid‐sensing ion channels (ASICs) through protonation reactions between electronegative atoms and hydrogen ions, even at ultralow driving voltage (5 mV). They can monitor joint cartilage acidity by tracking changes in proton concentration and successfully diagnose the onset of arthritis. Furthermore, by adjusting the synaptic device's cleft distance, which determines responsiveness, power efficiency and plasticity, HA‐based neuromorphic devices can be tailored to meet the unique demands of various implantation sites, providing both high‐sensitivity and low‐heat dissipation, thus broadening their application scopes. Moreover, the HA‐biodevices maintain stable performance across various bending degrees, up to a curvature radius of 7.5 mm, with flexibility and deformation resilience enabling installation on joints of varying curvatures. The combination of all‐biocompatibility, high sensitivity, low heat dissipation, ultralow low power (2 pW), and extraordinary deformation tolerance paves the way for the development of versatile, multipurpose medical monitoring devices with immense potential in the field of healthcare.