Bacteria-busting bandages – new technology fights wound infections

A research project uniting experts in chemistry, photo-physics, microbiology and tissue engineering at the University of Sheffield is close to producing a medical dressing capable of detecting and removing bacteria from a wound.

Dr Steve Rimmer, of the Department of Chemistry, is leading a multidisciplinary team investigating the use of a 'smart polymers' for the detection of bacteria. The polymers are able to detect bacteria due to their structure.

Polymers are composed of molecules which have highly branched chain ends and these have been functionalised to attach to the cell surface of bacteria, causing the polymer to collapse. The team hope in the very near future to produce a system that emits a different wavelength of light as the polymer collapses so providing a visual detection system. For several years Steve Rimmer and Linda Swanson, also of the Chemistry Department, have collaborated on using fluorescence techniques to study this molecular collapse process and they are now applying this expertise to the design of these new sensor materials. As the polymers 'grab' the bacteria they collapse holding the bacteria in a 'net' and this opens up the possibility of removing bacteria from wounds by removing a polymer-based bandage.

Professor Ian Douglas, of the University's Dental School, is the team member whose expertise in microbiology enabled the team to identify different types of end groups capable of detecting the two major types of bacteria, gram negative and gram positive. The team achieved a breakthrough when they successfully designed a material that collapsed as it bound to bacteria.

In the absence of bacteria the polymer has a collapse temperature above 37 degrees Celsius, roughly the temperature of the human body, but when bound to bacteria the collapse temperature drops below 37 degrees. This is particularly important given that the team aim to use the bacteria sensing polymer technology in medical applications.

Their ultimate aim is to fine-tune the technology to be able to detect different species, including MRSA and C. difficile. The final member of the team, Professor Sheila MacNeil of the Kroto Research Institute, worked with Professor Ian Douglas to develop a 3D tissue engineered skin model which is infected with bacteria to mimic the problems of chronic infected non-healing ulcers. The bacteria-grabbing polymer reduces the level of infection of these wounds and this model is proving very valuable in the further development of these polymers. The team are working on developing a medical dressing containing the bacteria 'grabbing' polymers, and aim to develop the technology to give a visual indication, such as a change in colour, of whether a bacterial infection is present.

Dr Rimmer and his team plan to incorporate the bacteria sensing polymers into membranes, such as wound dressings, which will have important medical implications for tackling bacterial infections in hospitals. The Ministry of Defence are also part funding the project because of its potential to improve medical care for front line soldiers. Dr Rimmer said: "We are developing a range of polymers capable of detecting specific bacteria. Once placed on a hydrogel dressing, the technology will be able to detect and remove a range of bacteria from wounds".

For further information, please contact Ian Kingsbury:

tel: 0114 222 1456

email : i.r.kingsbury@sheffield.ac.uk