Laser-assisted direct coating of Graphene-Based films on plastic substrates with bactericidal properties

Bacterial growth on surfaces is a substantial problem in medical equipment, fresh food storage, and water supply industries. Antibacterial coatings offer a preferred method to prevent this dangerous hazard. However, to provide a complete solution, the developed coating must not only efficiently prevent bacterial growth and consist of cost-effective, stable, and bio-friendly materials but also offer a simple coating method. In this work, we use novel laser processing that offers significant advancements, including (1) fast, single-step, and waste-free synthesis, (2) allowing direct printing of graphene over any substrate, including thermal-sensitive materials (i.e., polymers), and (3) micron-resolution patterning of the coated materials. We use an intense laser beam to fabricate metal-oxide/graphene nanoparticle composite films directly on plastic surfaces. The metal-oxide nanoparticles (cobalt and copper) are tested for antibacterial activity. Due to the combined formation, the metal-oxide nanoparticles are highly dispersed and firmly adhered to the graphene matrix. Notably, the structure and properties of the laser product, such as the nanoparticle's size and the graphitization level, can be controlled by tuning laser parameters. The composite coatings demonstrate excellent antibacterial activity. Studying substrates coated with different metal compositions found that 4.5–5 % of metal contents have antibacterial activity (percentage inhibition) by 89 % (PBS). Additionally, leaching studies demonstrate that the fabricated substrates are stable in different pH solutions.