United States. To limit hospital- and clinic-related infections, institutions have been using new materials, such as a commercially available one that mimics shark skin, to inhibit the ability of microbes to attach to high-touch areas such as bed rails and door knobs.
But over time, bacteria will accumulate, making this method insufficient, say researchers led by polymer scientist James Watkins at the University of Massachusetts Amherst.
Now, in a report published in the journal American Chemical Society ACS Applied Materials & Interfaces, Watkins and chemical engineer Jessica Schiffman, with a team of their graduate students, say they designed an easily applied coating with photocatalytic antimicrobial titanium dioxide (TiO2) nanoparticles that decrease microbial fixation and deactivate bacteria that are already attached to surfaces.
As they explain, when TiO2 nanoparticles are exposed to ultraviolet (UV) light, chemical reactions with water and hydroxide form reactive hydroxyl radicals and superoxide ions that break down the outer membranes of bacteria on contact and lead to cell death.
In addition, TiO2 nanoparticles are inexpensive, widely available, and can be incorporated into transparent coatings, unlike better-known antimicrobials such as silver and copper.
"These advantages make TiO2 an attractive candidate for use in high-contact surface antimicrobial coatings," they note.
Author and PhD in polymer sciences Feyza Dundar Arisoy and her colleagues used advanced roll-to-roll manufacturing capabilities in Watkins' lab at the UMass Amherst Institute for Applied Life Sciences to print their own surfaces mimicking shark skin from polymer and ceramic compounds impregnated with TiO2 nanoparticles.
They report that in their experiments, the surface of the shark's skin without nanoparticles reduced E. coli binding by 70 percent compared to smooth films. But shark skin surfaces with TiO2 nanoparticles exposed to ultraviolet light for an hour killed more than 95 percent of E. coli and 80 percent of harmful Staphylococcus aureus.
The researchers add that the surface properties of their nanoprinted lithography materials can be adjusted for different applications and environments, from soft and flexible polymers to extremely hard and wear-resistant ceramics, and their manufacturing method can be extended for the mass production of high-performance coatings. that repel and inactivate bacteria.
Arisoy and colleagues observe: "To our knowledge, this work represents the first reported use of antibacterial nanoparticles in shark skin patterns. The combination of passive and active strategies on a single surface is the most promising material design strategy for controlling bacterial fouling."
Data Source Provider: University of Massachusetts Amherst.
