Laser-induced freestanding graphene with porous nanostructure for antimicrobial devices and inhibition of microbial fouling

Laser-induced graphene (LIG) is a novel strategy for preparing graphene by taking advantage of the sufficient photothermal and photochemical reactions to develop nanomaterials with good physical and chemical properties. Recently, considerable research is devoted to efficiently prepare graphene antimicrobial devices taking advantage of the size and shape customizability of laser processing. However, the relationship between quantification of reduction rate and graphene nanostructure porosity has not been systematically studied. Hence, in this paper we applied a simple and efficient method to prepare graphene antibacterial paper by in situ reduction of polyimide in one step by exploiting the absorption of laser photon energy by the chemical bonds in the precursor material. And we further clarified the antibacterial mechanism of laser-induced graphene paper (LIGP) with the aim of achieving better antimicrobial performance by microstructure modulation through laser processing parameters. Microscopic analyses and colony counting assay were employed to demonstrate the antibacterial effect of graphene. Notably, LIGP at 1.0W laser power (LIGP-1.0W) exhibits the most significant bactericidal rate (94.1% for E. coli and 97.5% for S. aureus) attributed to its extremely high specific surface area (SSA, 189.3 m2 /g), the unique tunable nonporous structure increases extensive contact area with bacteria to provide more sites for capturing bacteria, which was further verified by oxidative stress-related mechanism. The prepared LIGP device can be used to prevent aluminum biocorrosion on material surface and used as antibacterial devices which can be customized to match diverse application scenarios.