Laser-Induced Graphene Papers with Tunable Microstructures as Antibacterial Agents

Abstract

Laser-induced graphene (LIG) has recently been attracting attention as a highly efficient method to process antimicrobial materials with scalable sizes and tunable properties. In this work, freestanding graphene papers are systematically investigated to study their process- and structure-dependent antibacterial activities against both Gram-positive and Gram-negative species. In addition to microscopy analyses for qualitative discussion of live and dead cells, a colony counting assay is applied to precisely quantify the loss of viability of bacteria treated by various laser-induced graphene papers (LIGPs) with tunable microstructures. Remarkably, the 1.25 W-processed LIGPs (LIGP-1.25 W) exhibit the highest reduction rate of 92.8% for Escherichia coli (E. coli) and 95.2% for Staphylococcus aureus (S. aureus), compared with LIGPs processed under 0.75 W (LIGP-0.75 W) and 1.75 W (LIGP-1.75 W). In addition to proving the combined membrane stress and reactive oxygen species (ROS)-independent oxidative stress-related mechanisms, the specific interconnected open-cell network with the highest specific surface area (171.6 m2/g) is found to be the determinant with fruitful bacteria trapping sites. Finally, corrosion resistance test is applied for demonstrating the capability of LIGPs for protecting the aluminum alloy sheet against immersion invasion of E. coli suspension up to 3 weeks, suggesting their great potentiality for facilitating advanced environmental protection activities.

Recent advances and mechanism of antimicrobial efficacy of graphene-based materials: a review

“…aureus [ 87 ] Gt, GtO, GO, and rGO 0.040 µg/µL G − ve: E. coli [ 57 ] LIG paper – G − ve: E . coli [ 79 ] G + ve: S . aureus GO-metal sheet – G − ve: E .…”

Laser-Induced Graphene Capacitive Killing of Bacteria

“…Graphene is a two-dimensional (2D) hexagonal lattice of sp 2 carbon atoms that are covalently bonded within two planar directions . In addition to its high thermal and electrical conductivity, flexibility, and mechanical strength, graphene has an exceptionally high surface area (e.g., ∼2600 m 2 /g) and intrinsic theoretical capacitance (21 μF/cm 2 ). − These properties perfectly poise this carbonaceous nanomaterial to be used within a broad array of applications ranging from electronics − (e.g., supercapacitors) and biotechnology to environmental technology − (e.g., renewable construction materials). − Within the spectra of environmental technology, examples of graphene derivatives have been shown to be antibacterial by many researchers over the years . The potency of graphene-based materials is especially true in the presence of an applied voltage as exemplified by laser-induced graphene (LIG). , However, the exact mechanism for the antibacterial activity such as the physical destruction of the cell membrane via direct contact of the bacteria with the surface structure/texture chemical microbial toxicity such as oxidative stress, or electrical effects of LIG or other graphene-based materials remains ambiguous and can be attributed to any combination of the various mechanisms.…”

Laser-induced direct graphene patterning: from formation mechanism to flexible applications

“…To fabricate the thinner flexible electronics with smaller linewidth, selecting a laser with shorter wavelengths (e.g., 355 nm [40,41] ) and controlling process parameters are two common methods, which enable the fabrication of the visually invisible LIG with a linewidth of 10 μm [42] . Besides, any desired LIG pattern can be directly fabricated on various flexible substrates, including polyimide [43,44] , polyethylene terephthalate [45] , PDMS [46][47][48] , and flexible cellulose paper [49][50][51] . In particular, the properties of LIG, including hole size, hydrophilic/hydrophobic, and square resistance, have been proven to be adjustable [52,53] .…”