We've already seen antibacterial surfaces that kill microbes on contact, but scientists in the UK have recently gone a different and potentially more effective route. They've created maze-like surface patterns that keep bacteria from sticking around to establish problematic biofilm colonies.
If only small numbers of bacteria are present on the surface of an implant, catheter, breathing tube or other medical device, they typically aren't all that harmful. Serious problems such as infections may arise, however, when those bacteria reproduce to form thick, slimy, treatment-resistant colonies known as biofilms.
Infusing surface materials with gradually-released antibiotics can help keep this from happening, but they cause the bacteria to evolve a resistance to the drugs over time. The antibiotics may also produce unwanted side effects in the surrounding tissue of the patient's body, plus the material will eventually run out of them.
Seeking a more sustainable alternative, a team at the University of Nottingham looked to biofilm-preventing microscopic patterns that could be added to the surface of existing plastic medical devices.
Led by professors Paul Williams and Morgan Alexander, the scientists experimented with 2,176 different patterns, which were developed using machine learning algorithms. Those patterns were embossed into the surface of flat polystyrene chips, which were subsequently inoculated with Pseudomonas aeruginosa and other types of bacteria.
The best-performing pattern consisted of a grid-like network of narrow channels running between taller features.
When the bacteria became trapped in those channels, they produced a lubricant to get back out. That lubricant kept them and other microbes from sticking to the plastic, meaning they couldn't form biofilms. As a result, the likelihood of infection was reduced by up to 15-fold as compared to regular un-embossed plastic.
"Using physically pattered surfaces has the advantage over coating approaches in that it can be applied to existing device materials, reducing the barrier to commercial application," says Prof. Alexander. "Our discovery could save the NHS [National Health Service] a lot of money.”
The research is described in a paper that was recently published in the journal Nature Communications.
Source: University of Nottingham
