In the cosmetics and personal care world zinc oxide is best known as one of the most effective sunscreen ingredients, but new research points to highly effective anti-bacterial applications.

Further investigation of the ingredients known anti-bacterial properties by researchers at the University of Michigan show that it could potentially have medical applications, specifically in the prevention of infections for implants such as joint replacements or heart valves.

Micronized and nano zinc oxide is probably the most widespread sunscreen ingredient, used particularly for its UVA absorbing properties, but it is also used as in a variety of over-the-counter medical products, from calamine lotion to diaper rash products and antiseptic ointments. Indeed the research could throw light on enhancing the antibacterial properties in these products.

It's all in the pyramid shape

Drilling deeper into the properties of the compound, the researchers at University of Michigan found that a coating of zinc oxide nanopyramids can disrupt the growth of Staphylococcus aureus, the bacteria known as MRSA, by as much as 95% on the treated area.

"It is extremely difficult to treat these infections," said J. Scott VanEpps, a clinical lecturer and research fellow in the U-M Medical School's department of emergency medicine, whose team led the biological study.

Outbreaks of MRSA can lead to significant patient setbacks following surgeries, but researchers have continued to struggle to find solutions that might help to combat the problem.

Once an infection takes a hold, patients face the potentially toxic side effects of strong anti-biotic treatments, and if that course of action fails to resolve the problem, further surgery to have medical devices replaced again.

Coating implants could prevent bacteria setting in

The researchers say that the option of coating a zinc dioxide-based treatments on implants, could reduce the risk of bacterial outbreak post-surgery, although they do also stress that they are still in the early stages of the research.

The findings to date have been published in the current edition of the journal Nanomedicine, where it is highlighted that if the nanoparticles in the zinc dioxide treatment are shaped like a pyramid with a hexagon-shape base, then they are most effective at preventing an enzyme called beta-galactosidase from breaking down lactose into sugars that the bacteria feeds off.

The study findings point to the fact that this is because a pointed edge in the zinc oxide nanoparticle is able to insert itself in the building blocks of the enzyme, preventing them from being broken down so readily, in turn halting the process that allows the bacteria to proliferate.

To demonstrate this, the researchers used pegs coated with the nano zinc oxide treatment. The experiment showed that four pegs with the treatment showed a 95% reduction in the number of viable staphylococcal cells, compared to four pegs that remained untreated.

Research is still in the early stages

Although the researchers point out that there are still significant hurdles to overcome before the treatment could be approved for clinical use in patients, research on human cells will be the next logical step in moving the research forward.

"The strong antibacterial activity against MRSA and other pathogens is an exciting finding," said Nicholas Kotov, the Joseph B. and Florence V. Cejka Professor of Chemical Engineering.

"We want to better understand the mechanisms of the antibacterial function to fine tune its inhibitory activity and to identify the structural similarities among enzymes that pyramidal nanoparticles can inhibit."

Cosmetics Design, (12/11/2015)