Electroconductive, Adhesive, Non‐Swelling, and Viscoelastic Hydrogels for Bioelectronics. Issue 4 (29th July 2022)

• Record Type: Journal Article
• Authors: Han, Im Kyung; Song, Kang‐Il; Jung, Sang‐Mun; Jo, Yeonggwon; Kwon, Jaesub; Chung, Taehun; Yoo, Surim; Jang, Jinah; Kim, Yong‐Tae; Hwang, Dong Soo; Kim, Youn Soo
• Is Part Of: Advanced materials. Volume 35:Issue 4(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-07-29
• Subjects: adhesive hydrogels -- bioelectronics -- conductive hydrogels -- electrode–tissue interfaces -- viscoelastic hydrogels; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202203431
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: As a new class of materials, implantable flexible electrical conductors have recently been developed and applied to bioelectronics. An ideal electrical conductor requires high conductivity, tissue‐like mechanical properties, low toxicity, reliable adhesion to biological tissues, and the ability to maintain its shape in wet physiological environments. Despite significant advances, electrical conductors that satisfy all these requirements are insufficient. Herein, a facile method for manufacturing a new conductive hydrogels through the simultaneous exfoliation of graphite and polymerization of zwitterionic monomers triggered by microwave irradiation is introduced. The mechanical properties of the obtained conductive hydrogel are similar to those of living tissue, which is ideal as a bionic adhesive for minimizing contact damage due to mechanical mismatches between hard electronics and soft tissues. Furthermore, it exhibits excellent adhesion performance, electrical conductivity, non‐swelling, and high conformability in water. Excellent biocompatibility of the hydrogel is confirmed through a cytotoxicity test using C2C12 cells, a biocompatibility test on rat tissues, and their histological analysis. The hydrogel is then implanted into the sciatic nerve of a rat and neuromodulation is demonstrated through low‐current electrical stimulation. This hydrogel demonstrates a tissue‐like extraneuronal electrode, which possesses high conformability to improve the tissue–electronics interfaces, promising next‐generation bioelectronics applications. Abstract : A new conductive hydrogel is developed through the simultaneous exfoliation of graphite and polymerization of zwitterionic monomers triggered by microwave irradiation. This hydrogel demonstrates tissue‐like extraneuronal electrodes satisfying requirements of bioelectronics such as low storage modulus, high viscoelasticity, low toxicity, reliable adhesion, and conformability to biological tissues, and maintenance of conductivity and hydrogel volume in wet environments.