Scientists have discovered that laser-induced graphene (LIG) is a highly effective antifouling material and, when electrified, bacteria zapper. LIG is a spongy version of graphene, the single-atom layer of carbon atoms. The researchers have since suggested uses for the material in wearable electronics and other applications.

The growth of biofilm on surfaces with a solution containing Pseudomonas aeruginosa is observed on, from left, polyimide, graphite, and laser-induced graphene surfaces. Green, red, and blue represent live bacteria, dead bacteria, and extracellular polymeric substances, respectively. Bottom: a sheet of polyimide burned on the left to leave laser-induced graphene shows the graphene surface nearly free of growth.
(Credit: Arnusch Lab/BGU)

When used as electrodes with a small applied voltage, LIG becomes the bacterial equivalent of a backyard bug zapper. Tests without the charge confirmed what has long been known — that graphene-based nanoparticles have antibacterial properties. When 1.1–2.5 V were applied, the highly conductive LIG electrodes greatly enhanced those properties.

Under the microscope, the researchers watched as fluorescently tagged Pseudomonas aeruginosa bacteria in a solution with LIG electrodes above 1.1 V were drawn toward the anode. Above 1.5 V, the cells began to disappear and vanished completely within 30 seconds. At 2.5 V, bacteria disappeared almost completely from the surface after one second.

The researchers suspect bacteria may meet their demise through a combination of contact with the rough surface of LIG, the electrical charge, and toxicity from localized production of hydrogen peroxide. LIG’s anti-fouling properties keep dead bacteria from accumulating on the surface.