We already knew that copper kills bacteria on contact, as it releases ions that rupture bacterial cell membranes. The material could soon do so faster than ever, however, thanks to a new laser-based surface treatment.
One of the things that keeps copper from having more of an antibacterial effect than it does is its smooth surface texture, which provides relatively few points of contact between the microbes and the metal. As a result, it takes several hours for a sufficient quantity of ions to flow from the copper into the bacteria.
Led by Asst. Prof. Rahim Rahimi, scientists at Indiana's Purdue University set out to speed things up, utilizing a laser to etch nanoscale patterns onto samples of copper. Doing so gave the metal a rugged texture with considerably more surface area, greatly increasing the ion flow. When tested alongside untreated control samples, the laser-treated copper thus completely eradicated harmful bacteria (such as E. coli and MRSA) in as little as 40 minutes.
The single-step treatment process leaves the bulk of the underlying copper unchanged, so it retains all of its existing mechanical properties. Additionally, it doesn't involve the application of a separate antibacterial substance, that might leach off into the environment over time.
And as a side benefit, the technique also makes metal surfaces of any type more hydrophilic, or water-attracting. This means that if the technique were used on orthopedic implants that need to integrate with the surrounding bone tissue, bone cells would be more likely to migrate in and attach themselves to the surface of the implant.
It is believed that the technology could easily and inexpensively be scaled up for use in the manufacturing of medical devices or commonly touched items.
A paper on the research was recently published in the journal Advanced Materials Interfaces.
Source: Purdue University
