Locally amplified electric field in laser-induced graphene surfaces – role of nanofibers for enhanced microbial inactivation†

Abstract

Laser-induced graphene (LIG) shows excellent antimicrobial activity with a low applied voltage; however, the mechanism is inadequately understood. Herein, we investigate the role of the nanofibers of LIG in the electrochemical disinfection mechanism both experimentally and computationally. LIG with a nanofibrous surface performs better than non-nanofibrous/crushed LIG (Cr-LIG), showing enhanced microbial inactivation. The role of the induced electric field and electrochemical reactions in the disinfection mechanism is being elucidated. A COMSOL simulation is performed, which shows that the induced electric field on the nanofiber tips can reach up to >10⁶ V m⁻¹ and create localized charge generation (∼900 C m⁻³). This localized charge generation effect can result in enhanced charge transfer phenomena in one-dimensional surfaces for electrochemical functioning and cell membrane polarization. Our study demonstrates for the first time that nanofibrous LIG surfaces can intensify the electric field and the generation of oxidants during the electrochemical disinfection process. These results have potential applications not just in the field of disinfection but also in electrochemical sensing and other low-voltage operation procedures.