Novel antimicrobial surfaces to combat AMR infections in medical implants and devices

Despite tremendous improvements in surgical procedures, bacterial infection remains the dominant cause of medical device or implant failure, resulting in significant patient trauma and a huge burden on the NHS. Current solutions to combat such infections are largely based upon incorporation of chemicals (e.g. antibiotics) into the devices, but these approaches have a number of shortcomings. One of the biggest problems is the development of antimicrobial resistance amongst bacteria, which has been described by the government as a 'ticking time bomb' that poses an "apocalyptic" threat to public health. Thus a completely new way of killing antimicrobial-resistant (AMR) bacteria is urgently needed. This project explores a unique physical means to kill AMR bacteria by puncturing their cell walls with tiny spikes. Such structures are inspired by those found in nature on cicada wings and can be incorporated on the surface of implant biomaterials. This project aims to develop a range of innovative surfaces that are able to kill bacteria via nanospikes, including bacteria that are resistant to killing by antibiotics, and to determine exactly how the bacteria are being killed. With further commercial exploitation such novel antimicrobial surfaces have potential to be used for next-generation biomedical devices and implants, with improved performance compared to those devices in current use.

Medical implants and devices constitute an indispensable and vital component of modern healthcare, resulting in greater survival rates, particularly amongst critically ill patients. However, despite tremendous improvements in surgical procedures, biomaterial-associated bacterial infections remain the dominant cause for prosthetic device or implant failures, resulting in significant patient trauma and a huge healthcare burden on the NHS. Current solutions are largely based upon chemical means (e.g. antibiotics or antimicrobial agents such as silver), which have many shortcomings and limitations. There are also issues associated with the growing problem of antimicrobial resistant (AMR) bacteria. Thus, a completely new way of killing AMR bacteria is urgently needed. In this innovative project we will explore a unique physical means to combat biomaterial-associated bacterial infections, utilising novel surfaces that kill bacteria with nanospikes, that resemble the nanotextured surfaces found on cicada wings in nature and have already been shown to be effective at killing certain bacteria by us. We aim to develop a range of antimicrobial surfaces with nanospikes that exhibit bactericidal properties against a wide variety of infection-associated bacteria. We will also investigate the synergistic effect of enzyme functionalised nanospikes to target peptidoglycan layer within the bacterial cell walls in order to develop novel surfaces with maximum bactericidal properties against AMR bacteria. Taken together, the knowledge generated in this project will be used for the rational design and fabrication of future medical implants and devices to combat AMR infections. This will contribute to the priority areas of national health and the economy, benefiting both patients and the NHS.

The principal beneficiaries of this research proposal are the general public, especially those who require implanted medical devices. The main impact derives from development of novel antimicrobial biomaterials for use in medical implants or prostheses. Current medical devices have significantly improved modern healthcare, increasing patient survival rates, particularly for those critically ill. However, like other medical interventions, the insertion of medical devices can be associated with serious complications, of which infections remain the most common. This project aims to study novel biomaterials that kill bacteria using unique nanospike structures to rupture bacterial cell walls and are thus resistant to bacterial infection. This approach also has the significant advantage that it utilises a topographical bactericidal mechanism rather than the chemical mechanisms seen with current devices (e.g. antibiotics and silver). Thus this new approach has potential to be effective against antimicrobial resistant (AMR) bacteria. Ultimately development of such antimicrobial biomaterials has potential to improve healthcare practices using medical devices for the benefit of both patient wellbeing and associated socioeconomic costs on a global scale.
Development of novel antimicrobial materials for use in medical devices also has significant potential to attract R&D collaboration/investment from companies who fabricate biomedical implants and prostheses, in particular those transcutaneous implants used in orthopaedics and dentistry where infections remain the major concern. Examples include intraosseous transcutaneous amputation prostheses, external fixation pins, dental implants and abutments. Such devices are also particularly prone to infection by AMR bacteria. The provision of antimicrobial materials that utilise a novel bactericidal mechanism that is equally effective against AMR bacteria therefore has potential to significantly improve current manufacturing practices. Ultimately, exploitation of novel biomaterials for the development of next-generation medical devices with resistance to bacterial infection has potential to transform biomedical/biotechnology industries, and thus contribute to the nation's overall health and wealth creation.