Engineers at Heriot-Watt University are developing a tiny electronic sensor that will help medics heal wounds by “listening” to them. The microsensor will help patients, doctors and nurses manage how a wound heals by letting them monitor the tiny, microscale changes in tissue that are taking place below the bandages.
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It is estimated that wound care currently costs the UK health service between £4.5 and £5.1 billion pounds per year. It involves the healing of many different types of wound, with the accidents, surgical incisions, and bedsores that cause so many patients significant pain all presenting different challenges.
Some wounds can also become chronic, and in the case of older individuals with fragile skin, just a tiny cut can become infected and even require a limb to be amputated.
At present, a small number of specialist wound dressings are available, but the main way medics monitor how well a wound is healing is by simply removing the bandages and taking a look.
"At the moment, we judge the progress of wounds on patients' reports of pain and how the wound looks to the naked eye of health professionals,” says lead researcher Michael Crichton, an assistant professor in biomedical engineering at Heriot-Watt.
"Our smart sensor will alert the patient and their care team when intervention is needed to make sure the wound heals better, or when it is all progressing nicely under the bandage."
Understanding what happens in wounds at the microscale level
The Engineering and Physical Sciences Research Council has awarded Crichton £360,000 to work on a two-year project that aims to understand what exactly takes place in a wound.
Chrichton says there has been a lot of research looking at the biological properties of wounds, but that very little is known about the mechanics of wound healing, particularly at the microscale level, which is where changes take place at sub-hair-width scales:
"We're working to create a small sensor that can be embedded in a bandage to measure changes in a wound's properties without interfering with the process.”
The researchers want to bring data into the process by developing a microsensor that can be placed on the tissue surface and take mechanical measurements that will indicate how the tissue is changing and whether it needs a different dressing or treatment.
If we can do that, that will tell us if a wound is likely to be going in one way or another. And if we can measure it over time, then we don't need to keep on opening up a wound and saying, 'is it getting better or is it getting worse?'"
Michael Crichton, Assistant Professor
In order to understand what defines a healthy wound (for the sensors to pick up on), the researchers need to investigate how skin responds to being cut.
Doctoral student, Sara Medina Lombardero, is helping with this by carefully shaving a layer of fat from a sample of pigskin, which is a suitable analog for human tissue: "My part of the project...is to know how each layer of skin contributes to its mechanical properties.”
After cutting the skin into carefully measured strips, Lombardero creates a tiny incision in one of them and places the sample under an optic coherence tomography system – a sophisticated imaging device that produces detailed 3D images of the skin’s structure beneath the surface.
By doing this, she is able to see the cut: "I can tell from this image that it is actually going through all the layers."
The ability to listen to bodily tissue at a microscopic level requires sensors that operate on the microscale. Crichton plans to use a speck-size sensor to transmit and receive tiny soundwaves.
"Ultimately it's a case of...allowing that sound to transfer through the tissue. We'll get an indication of how quickly the sound is transmitted, and that will give us an idea of the strength of the tissue underneath," he explains.
Using the approach to treat more than wounds
Although the team is currently looking at wound healing, the approach they develop could be used to treat more than wounds; the ability to listen to the body’s tissue may one day help medics to monitor and treat cancer or damaged organs.
“Some tissues and organs have the same structural components as skin, so researchers and practitioners in those areas are likely to take a great interest in our project,” says Chrichton.
The project is also likely to spark interest from the pharmaceutical industry, where the creams, gels and dressings that could be made available as other viable treatment options for patients and healthcare providers represent a market of billions of dollars.
Crichton’s multidisciplinary team includes Dr Jenna Cash, a specialist in wound healing immunology at Edinburgh University.
This is an innovative, patient-focused research project that addresses the urgent need for us to better understand wounds. Our work on the immunological response during healing is reflected in mechanical changes. Anything that combines these has the potential for new therapies."
Dr Jenna Cash