Nanotech treated surface can kill bacteria

Close-up image showing an untreated stainless steel sample (left), and a sample that has been electrochemically treated to create a nanotextured surface. Whilst bacteria can stick on normal stainless steel they get killed on the nanotextured one. Credit: Rob Felt, Georgia Tech

Researchers at Georgia Tech have discovered a particular nano-pattern that kills bacteria. They have created a nano-texture on a stainless steel surface consisting of spikes protruding 20-25 nm from the surface and have demonstrated that bacteria are killed, whilst mammalian cells, that are one order of magnitude larger, are not affected.  Although the mechanism killing the bacteria is not known yet it seems reasonable to assume that it is related to the specific pattern that penetrate the bacterial cell membrane. For sure it depends on the physical characteristics, not on chemical ones and as such it is not going to generate bacterial resistance.

The pattern was created using an electrochemical etching process and was part of a research looking for a super hydrophobic surface that was not dependant on chemical coatings (since these wear out with time). The electrochemical process is normally used to polish the steel. By varying the voltage and current flow the researchers discovered that it is possible to create specific surface patterns.

This discovery is of particular interest for steel implants, making them resistant to bacteria and hence protecting the patient from infection, one of the danger associated to implants. Additionally, it can be of use in the food treatment area providing stainless steel surfaces with a self sterilising capability (and this goes for the surfaces of the stove, the oven and the sink we have at home).

Another characteristic is an improved resistance to corrosion due to better isolation of chromium and molybdenum, the components that distinguish stainless steel from normal steel.

About Roberto Saracco

Roberto Saracco fell in love with technology and its implications long time ago. His background is in math and computer science. Until April 2017 he led the EIT Digital Italian Node and then was head of the Industrial Doctoral School of EIT Digital up to September 2018. Previously, up to December 2011 he was the Director of the Telecom Italia Future Centre in Venice, looking at the interplay of technology evolution, economics and society. At the turn of the century he led a World Bank-Infodev project to stimulate entrepreneurship in Latin America. He is a senior member of IEEE where he leads the New Initiative Committee and co-chairs the Digital Reality Initiative. He is a member of the IEEE in 2050 Ad Hoc Committee. He teaches a Master course on Technology Forecasting and Market impact at the University of Trento. He has published over 100 papers in journals and magazines and 14 books.