I’ve developed several patent-pending technologies in the area of antibacterial surfaces. From the standpoint of an organic chemist (I have 12 years of experience in that field, post-graduate), crafting an antibacterial surface usually means decorating the surface with a thin layer of organic fragments known to be harmful to bacteria. Some strategies use the active ingredient in Lysol-type sprays, and some use phenolic compounds. It’s not always simple to decorate a surface with antibacterial groups, nor is it necessarily cheap. I’ve done a lot of work trying to find low-cost alternatives to known systems, with some success, but I’m painfully aware that the current solutions are somewhat lacking.
The need for antibacterial surfaces is high. Just about every surface in a hospital could benefit from this type of technology, as could many household items. Another area is the paint used on marine hulls; the growth of bacteria on ships leads to biofilms and the attachment of barnacles. This “biofouling” increases the drag on marine vessels, leading to wasted fuel and all the environmental impact that the wasted fuel entails. It’s an important area of science, and trying to stay one step ahead of the bacteria (with all their varied defenses and immunities) can be difficult.
That’s why I was interested, even amazed, to read a recent article in the American Chemical Society publication ACS Nano that outlined a low-cost, simple technology. It promises to lead the pack in the area of antibacterial surfaces. In the last several years, scientists across the world have been studying the properties of graphene, which is a thin sheet-like compound made entirely out of carbon. Recently, a team of Chinese chemists have been studying graphene oxide. This compound has a graphene core but it has oxygen atoms attached to the surface. This material is flexible and free-standing, meaning that it doesn’t need any support to hold up it’s own weight. The method used in the article to produce the graphene oxide could theoretically be scaled up and fine-tuned in order to lower the cost; the processing is not difficult and it doesn’t require a large amount of different chemical steps.
Essentially, all the scientists did was prepare a suspension of graphene oxide particles in a solvent. This black, cloudy dispersion was then vacuum filtered through a fritted glass funnel. The pores in the glass frit allow the solvent to filter through, but the graphene oxide material is too large, and so it accumulates on top of the frit. After all the solution has been poured through the funnel and the accumulated graphene oxide is dry, the mat of particles can be picked up with tweezers to form a thin sheet. The researchers attempted to grow E. Coli on top of the sheet, and discovered that the graphene oxide inhibited the growth of the bacteria. The sheet also didn’t have any cytotoxic effects, meaning that it wasn’t harmful to normal cells.
As someone who’s very active in this area, this discovery is very exciting for me. It’s not clear what mechanism is preventing the bacteria from growing on the graphene oxide, or if the technology will ever be marketed widely. However, it’s possible that one day we’ll see black sheets of antibacterial graphene oxide in hospitals, at home, and in restaurants. It’s a worthwhile discovery, and I was happy to read about it.
The source of this article can be found at:
Hu, W., et al. “Graphene-based antibacterial paper”. ACS Nano, 2010, 4, 4317-4323.