Tiny dot that shows early signs of infection, invented by NI scientists

Non-invasive indicator does not make contact with wound but sniffs the air above it

A small dot that changes colour if a patient’s wound shows early signs of infection has been invented by scientists at Queen’s University Belfast.

The non-invasive indicator does not make any contact with the wound but detects the beginnings of infection by sniffing the air above it – it is the same size as a fingertip.

It is the first of its kind and is predicted to bring major benefits to healthcare, especially because it can be added to already existing bandages. It allows infections to be detected without taking off a dressing, which can inhibit healing and increase likelihood of wound infection.

It is estimated that 1 to 2 per cent of people in developed countries will experience a chronic wound in their lifetime; the UK spends £3.2 billion (€3.8bn) a year treating the problem.

Prof Andrew Mills from the School of Chemistry and Chemical Engineering at Queen's who is leading the project underlined its potential. "The colour-changing indicator we have developed is just a tiny dot but it could have hugely positive benefits for our patients and health care systems worldwide."

Usually if a patient has a wound, especially a chronic wound, a nurse or doctor will check for infection every two to three days by removing the dressing. “Changing a dressing can be unnecessary, painful and an infection risk. All of this could be avoided with our indicator, saving time, money and pain,” he added.

If infection is starting in a wound, there is often a sudden growth of aerobic microbiological species and as they grow they generate carbon dioxide, he explained. “Our indicator detects this rise in carbon dioxide causing the dot to change colour, flagging the infection in its very early stages before it actually takes hold and overwhelms the patient’s immune system. This means it can be treated quickly, avoiding unnecessary pain for the patient and significantly reducing the possible need for hospitalisation.”

Their findings have been published in the Royal Society of Chemistry's ChemComm journal.

Prof Brendan Gilmore from QUB School of Pharmacy added: "This sensor can provide an early warning of infection before it has progressed to a chronic, persistent colonisation of the wound by microorganisms which are by then much more difficult to treat effectively with antibiotics."

The sensors respond quickly to the presence of infection, and allow healthcare providers to make informed decisions about managing the wound, including whether or not to use antibiotics, he noted. “Inappropriate antibiotic use is known to drive the emergence of antibiotic resistance. Crucially, these sensors can tell us whether or not the intervention has worked in killing the microorganisms which caused these infections.”

The researchers plan to develop an app so patients will be alerted if there is an infection. The same information would also be sent to their nurse or doctor, and be used to inform treatment plans.

Prof Mills said there were pleased to be able to offer a simple, inexpensive, non-invasive way to monitor the progress of healing wounds. “We are currently in discussions with industry in how to take this forward and we hope to run clinical trials soon,” he confirmed.