Plasma polymerisation of nitric oxide release coatings to inhibit biofilm formation

Plasma polymerisation is an important surface engineering process capable of depositing ultra-thin films for a variety of purposes. It is widely used in manufacturing, and we would hope to extend the range of products that can be plasma coated. Our focus is on coatings in healthcare applications.

We are all likely to be beneficiaries from the development of effective, safe and low-cost technologies that address the rise in antimicrobial resistance (AMR); microbes that develop resistance to antibiotics. As identified by Lord Jim O'Neill in his seminal report Review on Antimicrobial Resistance: Tackling Drug-Resistant Infections Globally (2016), AMR presents perhaps the greatest long-term threat to human health: it is estimated that up to 10 million people per year will die from AMR by 2050, without significant new interventions.

The PhD student will explore plasma coatings that can release an important biological molecule, nitric oxide (NO). The NO molecule regulates bacterial processes, and is used as an antibacterial agent to reduce bacterial attachment and biofilm formation. This is particularly important as biofilms are extraordinarily hard to treat, requiring up to x1000 the concentration of antibiotic.

A particularly interesting application for these coatings is in catheters, both blood dwelling and urinary. Catheters are one of the most commonly implanted types of medical device (for example, there are c. 5 million blood-dwelling catheters inserted in the US per year). Biofilm formation is the major reason for retrieval of medical devices. The prevention of infection would reduce constant removal, and reduce number of infections and related deaths.

We can further see a market for these surfaces (applied as dressings) in the treatment of wounds. Burn wounds, for example, are particularly prone to bacterial colonisation. Dressings containing silver have been used for about two decades, but recently questions about silver toxicity to mammalian cells and overall benefit from the use of silver have arisen, prompting medical technology companies to look for alternate approaches.

In this context, NO release surfaces could provide a less toxic and yet equally effective approach. Diabetic wounds (ca. 200,000 - 300,000 pa in the UK) provide an alternative target, where infection is a common reason for wounds failing to heal. A further target is hospital acquired infections which cost the NHS ca. £1Bn pa and approximately 24% of these are at the surgical site.

The successful PhD student will use plasma polymerisation to develop stable NO-releasing coatings to prevent formation of biofilms for medical device applications. They will join an experienced plasma research group led by Prof. Rob Short (30+ years experience with plasma polymerisation and medical technologies).

They will explore and optimise plasma conditions suitable for coating development, and characterise these coatings with advanced analytical techniques such as X-ray Photoelectron Spectroscopy (XPS). Coatings will also be tested in microbiology facilities to assess microbial attachment and biofilm resistance. The project provides training in plasma chemistry, advanced analytical techniques, and an introduction to the fascinating world of microbiology.