Antibiotics are often given to hospital patients, even following the most routine operations, to counter the risk of bacterial infections and viruses.
Now, materials scientists at the University of Manchester have developed a ‘durable and washable, concrete-link’ composite material that boasts antibacterial properties, with the aim of binding the material to doctors’, nurses’ and healthcare professionals’ uniforms.
Bacterial infection is a major issue in hospitals across the UK, and is known to spread via surfaces and clothing. E. coli infections alone killed more than 5,500 NHS patients in 2015, and the UK government estimates the cost of such infections to the NHS at £2.3 billion this year alone.
But doctors, nurses and healthcare professionals could soon be wearing uniforms brushed with tiny copper nanoparticles to reduce the spread of bacterial infections and viruses. Working in collaboration with universities in China, the Manchester team created the composite material using antibacterial copper nanoparticles.
They have also developed a way to bind the composite to wearable materials such as cotton and polyester - a stumbling block for scientists in the past.
Precious metals, such as gold and silver, have excellent antibacterial and antimicrobial properties, but their commercial use in textiles is prohibitive due to extremely high costs. That means copper is the material of choice for researchers, as it has very similar antibacterial properties to gold and silver but is much cheaper.
Using a process called polymer surface grafting, the research team tethered copper nanoparticles to cotton and polyester using a polymer brush, creating a strong chemical bond. The researchers claim this bond creates excellent washable properties and , and could see copper-covered uniforms and textiles commercialised in the future.
'Now that our composite materials present excellent antibacterial properties and durability, it has huge potential for modern medical and healthcare applications,’ Lead author, Dr Xuqing Liu, said.
The researchers tested their copper nanoparticles on cotton as it is used more widely than any other natural fibre and polyester as it is a typical polymeric, manmade material. Each material was brushed with the tiny copper nanoparticles, which measure between 1-100 nanometres (nm). 100nm is the equivalent to just 0.0001 millimetres (mm) - a human hair is approximately 90,000nm wide.
The team found their cotton and polyester coated-copper fabrics showed excellent antibacterial resistance against Staphylococcus aureus (S. aureus) and E. coli, even after being washed 30 times.
Some could argue the greatest threat to life as we know it is the slow, invisible war being fought against antibiotic resistant bacteria. The accidental discovery of penicillin by Fleming in the late 1920s revolutionised modern medicine, beginning with their use in the Second World War.
Over-prescription of these wonder drugs has allowed bacteria, which multiply exponentially, the ability to pick up on deadly cues in their environment at a phenomenal rate. They’re adapting their defence mechanisms so they’re less susceptible to attack. In theory, with an endless supply of different drugs, this would be no big deal.
Alexander Fleming, who discovered penicillin. Image: Wikimedia Commons
Unfortunately, the drug pipeline seems to have run dry, whilst the incidence of resistance continues to climb. For the gnarliest of infections, there’s a list of ‘drugs of last resort’, but resistance even to some of these has recently been observed. A report published by the World Health Organisation echoes these warnings – of the 51 new drugs in clinical development, almost 85% can be considered an ‘upgraded’ version of ones on the market right now. These drugs are a band aid on a snowballing problem.
Are viruses the answer?
Bacteriophages, or phages for short, are viruses that infect only bacteria, wreaking havoc by hijacking cellular machinery for their growth and development.
A bacteriophage. Image: Vimeo
Phages can find themselves in one of two different life cycles: virulent and temperate. The first involves constant viral replication, killing bacteria by turning them inside out (a process known as lysis). The second life cycle allows the phage in question to hitch a ride in the cell it infects, integrating its genetic material into the host’s and in doing so, propagating without causing immediate destruction. It’s the former that is of value in phage therapy.
Long before Fleming’s discovery, phages were employed successfully to treat bacterial infections. In areas of Eastern Europe, phages have been in continuous clinical use since the early part of the 20th century.
Why did their use not take off like that of penicillin’s in the West? ‘Bad science’ that couldn’t be validated in the early days proved to be disheartening, and phages were pushed to the wayside. Renewed interest in the field has come about due to an improvement in our understanding of molecular genetics and cell biology.
Phages are highly specific and, unlike antibiotics, they don’t tamper with the colonies of bacteria that line our airways and make up a healthy gut microbiome. As they exploit an entirely different mode of action, phages can be used as a treatment against multiple drug-resistant bacteria.
Repeated dosing may not even be necessary – following initial treatment and replication of the phage within infected cells, cell lysis releases ever more phages. Once the infection is cleared, they’re excreted from the body with other waste products.
What is holding it back?
A number of key issues must be ironed out if phage therapy is to be adopted to fight infection as antibiotics have. High phage specificity means different phage concoctions might be needed to treat the same illness in two different people. Vast libraries must be created, updated and maintained. Internationally, who will be responsible for maintenance, and will there be implications for access?
Scientists are looking at new ways to tackle antibiotic resistance. Video: TEDx Talks
Despite proving a promising avenue for (re)exploration, under-investment in the field has hindered progress. Bacteriophage products prove hard to patent, impacting the willingness of pharmaceutical companies investing capital. AmpliPhi Biosciences, a San Diego-based biotech company that focuses on the ‘development and commercialization of novel bacteriophage-based antibacterial therapeutic,’ was granted a number of patents in 2016, showing it is possible. This holds some promise – viruses might not save us yet, but they could be well on their way to.