Some metals, such as silver, gold and copper, have antibacterial and antimicrobial properties; they are able to kill or limit the growth of microorganisms without greatly affecting a host. Adhering copper, the cheapest of the three, to clothing has proven challenging in the past. But in 2018, researchers from The University of Manchester and the Northwest Minzu and Southwest University in China have collaborated to create a unique process that effectively coats fabric with copper nanoparticles. These fabrics could be employed as antimicrobial hospital uniforms or other medical-use textiles.

image of nurse in uniform and copper in a dish, credit: COD Newsroom on Flickr, european-coatings.com

“These results are very positive, and some companies are already showing interest in developing this technology. We hope we can commercialize the advanced technology within a couple of years. We have now started to work on reducing cost and making the process even simpler,” Lead Author Dr. Xuqing Liu said.

During this study, copper nanoparticles were applied to cotton and polyester through a process called, “Polymer Surface Grafting.” The copper nanoparticles of between 1-100 nanometers were attached to the materials using a polymer brush. A polymer brush is an assembly of macromolecules (molecules containing large amounts of atoms) tethered at one end to a substrate or surface. This method created a strong chemical bond between the copper nanoparticles and the fabrics’ surfaces.

“It was found that copper nanoparticles were uniformly and firmly distributed on the surfaces,” according to the study abstract. The treated materials showed “efficient antibacterial activity” against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The new composite textiles these material scientists developed are also strong and washable – they still showed the antibacterial resistant activity after 30 wash cycles.

“Now that our composite material presents excellent antibacterial properties and durability, it has huge potential for modern medical and health care applications,” said Liu.

Bacterial infections are a serious health hazard worldwide. They can spread on clothing and surfaces within hospitals, costing tens of thousands of lives and billions of dollars annually in the U.S. alone.

Gregory Grass of the University of Nebraska-Lincoln has studied dry copper’s ability to kill microbes upon surface contact. While he feels copper surfaces cannot replace other essential hygiene-preservation methods in medical facilities, he thinks they “will certainly decrease the costs associated with hospital-acquired infections and curb human disease, as well as save lives.”

Metals have been used as antimicrobial agents for thousands of years and were replaced by organic antibiotics in the mid‐20th century. In a 2017 paper titled, “Metal‐based antimicrobial strategies,” Raymond Turner of the University of Calgary writes, “While research to date on MBAs ([metal‐based antimicrobials]) has considerable promise, the understanding of the toxicology of these metals on humans, livestock, crops and the microbial‐ecosystem as a whole is lacking.”

“Durable and Washable Antibacterial Copper Nanoparticles Bridged by Surface Grafting Polymer Brushes on Cotton and Polymeric Materials,” was published in the Journal of Nanomaterials in 2018.