Self-Assembly of Enzyme-Like Nanofibrous G-Molecular Hydrogel for Printed Flexible Electrochemical Sensors

Abstract

Conducting hydrogels provide great potential for creating designer shape-morphing architectures for biomedical applications owing to their unique solid–liquid interface and ease of processability. Here, a novel nanofibrous hydrogel with significant enzyme-like activity that can be used as "ink" to print flexible electrochemical devices is developed. The nanofibrous hydrogel is self-assembled from guanosine (G) and KB(OH)₄ with simultaneous incorporation of hemin into the G-quartet scaffold, giving rise to significant enzyme-like activity. The rapid switching between the sol and gel states responsive to shear stress enables free-form fabrication of different patterns. Furthermore, the replication of the G-quartet wires into a conductive matrix by in situ catalytic deposition of polyaniline on nanofibers is demonstrated, which can be directly printed into a flexible electrochemical electrode. By loading glucose oxidase into this novel hydrogel, a flexible glucose biosensor is developed. This study sheds new light on developing artificial enzymes with new functionalities and on fabrication of flexible bioelectronics.

A printed flexible electrochemical sensor is developed based on a novel enzyme-like nanofibrous hydrogel, which is self-assembled from natural product guanosine (G) monomers. The G-molecular hydrogel can serve as templates for hemin-catalyzed formation of polyaniline, and when it coats the gels gives electroconductive soft materials. The unique thixotropic behavior of the gel allows them to be used as inks for 3D printing.

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