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Georgia researchers develop nanotextured surface that kills bacteria on stainless steel

February 06, 2018
Source: ASM International

The Georgia Institute of Technology, Atlanta, announces that its researchers used an electrochemical etching process to create a nanotextured surface that kills bacteria on a common stainless steel alloy. If additional research supports early test results, the process might be used to attack microbial contamination on implantable medical devices and on food processing equipment.

While the specific mechanism by which the nanotextured material kills bacteria requires further study, the researchers believe tiny spikes and other nano-protrusions created on the surface puncture bacterial membranes to kill the bugs. The surface structures don't appear to have a similar effect on mammalian cells, which are an order of magnitude larger than the bacteria.
Beyond the anti-bacterial effects, the nano-texturing also appears to improve corrosion resistance. The research was reported December 12 in the journal ACS Biomaterials Science & Engineering.

"This surface treatment has potentially broad-ranging implications because stainless steel is so widely used and so many of the applications could benefit," said Julie Champion, an associate professor in Georgia Tech's School of Chemical and Biomolecular Engineering.Microscopic examination showed protrusions 20 to 25 nanometers above the surface. "It's like a mountain range with both sharp peaks and valleys.  We think the bacteria-killing effect is related to the size scale of these features, allowing them to interact with the membranes of the bacterial cells."

The researchers were surprised that the treated surface killed bacteria. And because the process appears to rely on a biophysical rather than chemical process, the bugs shouldn't be able to develop resistance to it, she added.

A second major potential application for the surface modification technique is food processing equipment. There, the surface treatment should prevent bacteria from adhering, enhancing existing sterilization techniques.

The researchers used samples of a common stainless alloy known as 316L, treating the surface with an electrochemical process in which current was applied to the metal surfaces while they were submerged in a nitric acid etching solution. 

Subject Classifications

Industries and Applications | Electronics

Industries and Applications | Medical Devices

Industries and Applications | Nanotechnology

Metals and Alloys | Stainless Steels

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