Smart dressing for chronic wound monitoring and improvement

Non-healing wounds (i.e. chronic wounds) are one major healthcare challenges that affect 2.2 million people in the U.K. and the annual cost incurred by the National health Service (NHS) in managing these wounds and associated comorbidities was £5.3 billion in 2015, which was equivalent to 5% of total expenditure in NHS. Early detection of infection enables the patient and healthcare professional to undertake treatment as early as possible to prevent more serious consequences such as limb amputation.

Current wound care dressings (i.e. bandages) are passive and cannot respond to changes in wound conditions, such as temperature. The key drawback of these dressings is the lack of information about the status of the wound bed, the rate of healing and the stage of wounding healing. As a result, the patients have to be regularly examined by the healthcare professional to assess healing progress and potential infections which significantly increases the pressure and financial burden to the NHS.

Smart dressings with various of sensors have been reported, such as those measuring temperature, pH, moisture level and local stress. To visualise the sensor output, colourimetry is often used to indicate the severity of measured data, although mobile App enabled through either Bluetooth or NFC is used. However, there is no report on the development of protein sensor that can be the part of a wound dressing and detect the protein variation in a wound bed in real time.

Our vision is to develop a smart dressing to continuously monitor protein variation through wearable sensors and then provide real time information about a wound to patients and clinicians. It is anticipated that the outcome from this project will impact a range of sectors, including healthcare, manufacturing, textiles and flexible electronics. Our ultimate goal is to benefit patients who are suffering from chronic wounds and their families.

Addressing the challenge

Since the dressing will be directly attached over the wound bed with the sensor integrated into its textile materials, the objective was to realise sensors that can be directly integrated within a conventional wound dressing. The sensor was therefore fabricated by printing functional inks directly onto the textile using a semi-automatic screen printer. Printing directly onto textiles improves the flexibility, stretchability and breathability of the finishing dressing, enhances the adhesion of sensors to textiles and provides an opportunity for mass production at a large scale.

The sensor was tested to evaluate the performance of measuring free protein in solution against binary protein standards, initially using skimmed milk as an economic source protein to design and calibrate the sensors, then bovine serum albumin and then human serum albumin. Albumin is the most abundant free protein in plasma and interstitial fluid. We intentionally were not aiming to measure any specific protein in a wound, and the final in-vitro matrix test would use simulated body fluid. This was principal because the hypothesis was that wet wounds in inflammatory stages will have more free protein than drying and sealing wounds.

It will be highly valuable to have an accurate discriminator to develop a sensor to measure the rate of protein accumulation as a marker of wound condition and the stage of healing. It may well prove possible to discriminate between proteins and types of inflammation and these would be interesting from a research perspective. The sensor design, material selection, fabrication parameters and interface circuit were studied during this project.

People

We have assembled a multidisciplinary team led by Dr Wei to tackle the challenges. Dr Wei has extensive experience on printed and micro/flexible electronic in medical applications.

Co-Is include Professor Hunt who has provided support on biosensing and looking into the medical device regulatory; Prof Moffatt who has provided clinical guidance on smart dressing.

The project brings expertise from different sectors within NTU, such as wearable devices, biomonitoring and Wound care, as well as industrial support from wearable healthcare and wound care sectors.

Making a difference

The project will result in a novel platform which puts the treatment of chronic wound into the hands of patients. The sensor allows the healing progress of wound to be monitored in real time, thus allowing early intervention to take place should the condition of wound worsen. The sensor data will be encrypted and then sent to the clinicians so the trend of wound healing of a particular patient can be monitored. In addition, the smart dressing allows the patient to check the healing of the wound at any time, any location using their phone without removing the dressing which could cause secondary damage.