Plasma activated nanobubbles: A new approach for high-level disinfection of flexible endoscopes

The use of flexible endoscopic devices has become a major feature of modern clinical practice, both for diagnostic applications and surgical interventions. Annually, between 15 and 20 million endoscopic procedures are conducted with reusable devices, worldwide. The nature of these devices makes them difficult to clean and disinfect effectively. Recent studies have identified gram-negative bacteria on 85% of disinfected colonoscopies, with over 55% of normally functioning scopes showing evidence of some biofilm formation. Such contamination presents a particularly resilient form of infection, posing a significant risk for the transmission of multidrug-resistant pathogens between patients. Current endoscope reprocessing techniques are time-consuming, costly and often involve the use of hazardous chemical agents; however, it is the fact that such methods are ill-suited to eliminate biofilm contamination that introduces the potential for cross-patient transmission of antimicrobial-resistant infection, necessitating urgent development of a new approach. To address this challenge, recent advances in the field of plasma-liquid interaction will be harnessed to realise a disruptive new biofilm decontamination technology. It is hypothesised, for the first time, that plasma generated nanobubbles can be used as a vehicle to deliver highly reactive antimicrobial chemical species directly into the matrix of a biofilm. To achieve this ambitious aim, state-of-the-art diagnostic techniques will be applied to explore the underpinning generation and transport mechanism of reactive chemical species as they propagate from the plasma through to microorganisms embedded within the complex extracellular matrix of a biofilm. To maximise impact, a proof-of-concept decontamination device will be created to demonstrate not only the feasibility of the approach but to provide a platform for future translational activities.