Nanotextured surface kills bacteria without hurting mammalian cells

Researchers at the Georgia Institute of Technology have created an electrochemical etching process that can be used on common stainless steel alloy that is able to kill bacteria without hurting mammalian cells. The team believes that the process may one day be used to prevent microbial attack on implantable medical devices and food processing equipment.

The researchers behind the new technique do admit that the specific mechanism that the nanotextured material uses to kill bacteria will require more study. The team believes that the bacteria-killing prowess of the material comes from the tiny spikes and nano-protrusions that are created on the surface of the material using the etching process.

The thought is that these tiny spikes are able to puncture bacterial membranes, killing the bacteria. Interestingly, the surface structures don't appear to have the same killing effect on mammalian cells because those cells are much larger than the bacteria. The same nano-texturing process appears to improve corrosion resistance.

The new surface treatment process has broad-ranging applications because stainless steel is widely used. The researchers note that other antimicrobial treatments wear off or rely on a surface film. This process modifies the steel itself and results in a permanent change.

The scientists were originally researching a super-hydrophobic surface for stainless steel to repel liquids and bacteria along with the liquid. However, the team found that would require a chemical coating and that wasn't a desired solution. The process invented uses varying levels of voltage and current flow in a standard electrochemical process.