A Multifunctional Electrochemical Biosensor Based on Near-Infrared Light-Responsive Hydrogel for In Vivo Recording and Modulation

Monitoring and regulating neural signals are crucial for the management of neurological disorders. Herein, we constructed a near-infrared light (NIR)-responsive device for controllable recording and modulation of neural signals based on enzyme-loaded microgels/multiwalled carbon nanotubes (MWCNTs) composite-modified microelectrodes. The embedded MWCNTs within the composites can convert NIR light into heat via a photothermal effect. Consequently, on one hand, the enzyme-catalyzed reactions on the electrode surface can be reversibly modulated by NIR light. Under NIR irradiation, the contraction of temperature-responsive microgels not only facilitates direct bioelectrocatalysis but also promotes enzyme cascade catalysis on the electrode surface. The proposed method can determine glucose concentrations ranging from 0.3 to 6.0 mM with a detection limit of 0.098 mM. Taking advantage of the superior antifouling ability and biocompatibility, this device was applied for controllable monitoring of glucose in vivo with excellent stability for up to 2 h. On the other hand, the implanted electrode enabled photothermal activation of TRPV1 channels, which further promoted the autophagy of microglia and the degradation of alpha-synuclein in the mouse brain with Parkinson's disease. We believe this proposed system, with high spatiotemporal controllability, biocompatibility, and multifunctionality, has great prospects for the diagnostics and therapeutics of neurodegenerative diseases.