Rice, Ben-Gurion universities show laser-induced graphene kills bacteria, resists biofouling
Scientists at Rice University and Ben-Gurion University of the Negev (BGU) have discovered that laser-induced graphene (LIG) is a highly effective anti-fouling material and, when electrified, bacteria zapper.
LIG is a spongy version of graphene, the single-atom layer of carbon atoms. The Rice lab of chemist James Tour developed it three years ago by burning partway through an inexpensive polyimide sheet with a laser, which turned the surface into a lattice of interconnected graphene sheets. The researchers have since suggested uses for the material in wearable electronics and fuel cells and for superhydrophobic or superhydrophilic surfaces.
In this real-time video, Pseudomonas aeruginosa bacteria tagged with green fluorescent protein, which appear as bright dots, are drawn to an anode of laser-induced graphene, where they die. The anode at the top, which is separated from a cathode by a 100-micron channel, carries a small voltage that boosts its antibacterial properties. Courtesy of the Arnusch Lab/BGU
According to their report in the American Chemical Society’s ACS Applied Materials and Interfaces, LIG also protects surfaces from biofouling, the buildup of microorganisms, plants or other biological material on wet surfaces.
“This form of graphene is extremely resistant to biofilm formation, which has promise for places like water-treatment plants, oil-drilling operations, hospitals and ocean applications like underwater pipes that are sensitive to fouling,” Tour said. “The antibacterial qualities when electricity is applied is a great additional benefit.”
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 to 2.5 volts 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 volts were drawn toward the anode. Above 1.5 volts, the cells began to disappear and vanished completely within 30 seconds. At 2.5 volts, bacteria disappeared almost completely from the surface after one second.