3D Printed, Stand-alone, Colourimetric Indicator Strip (3DCIS) for Non-Invasive, On-demand Chronic Wound Monitoring

Chronic wounds have been referred to as the 'silent epidemic' that affects a significant proportion, 1-2 %, of the population during their lifetime. The main causes of chronic wounds are: diabetes, burns and pressure ulcers and, as the term 'chronic' suggests, they are not readily cured. Thus, in a recent study almost 42% of leg/foot ulcers had not healed in the previous 6 months and 28% had remained unhealed for a year or longer. In all countries, chronic woundcare places a considerable burden upon the local and national health services. For example, in the UK, some 650,000 patients suffer from some form of chronic wound, resulting in an annual cost of ca. £3 Bn, and in the USA there are about 6.5 M suffers, whose treatment costs ca. £25 Bn pa. Venous ulcers, which usually occur in the legs, account for 70-90% of chronic wounds and mostly affect the elderly. It follows that since the global average life expectancy continues to rise then so too will the number of incidences, and cost, of treatment of chronic wounds. The combined cost to the NHS for their treatment reaches approximately £3 billion per year. There is a clear need for an inexpensive, disposable wound monitoring method that can be: (i) readily incorporated into a wound dressing, thereby rendering it smart and, (ii) able to provide clinicians, nurses and patients with a continuous, or semi-continuous, stream of information about key biomarkers, i.e. biochemical cues, which would help identify the condition/status of the wound and so flag up wounds that are not healing properly and that require medical intervention. The proposed technology involves the 3D printing of a multi-analyte strip, comprised of four different colour-based indicators which are selective in response to four different gaseous bio-markers, namely: CO2, volatile amines (RNH2), humidity (H2O) and O2. This strip will provide a semi-continuous, on-demand, stream of information concerning the composition of the headspace above the wound and contained by the dressing. The proposed multi-analyte, in situ, volatile analysis, afforded by this simple, stand-alone, colour strip, has a number of advantages compared to existing wound monitoring methods, which include: (1) complete strip production using 3D printing technology, (2) simple colour changes that can be read by eye or digital camera, (3) simple to incorporate into an existing wound dressing (i.e. stand-alone), (4) easy to interpret, (5) logged data trends and automatic real-time alerts (6) inexpensive, (7) non-contact/non-invasive, (8) applicable in a wide number of healthcare environments (including: point of care, outpatients, hospital wards and home care), (9) scope for application in other areas, both medical, such as in acute wound dressings, and non-medical, such as food and electronic goods packaging, (10) amenable to microfabrication and (11) scope for other analytes to be added, such as temperature and volatile sulfides.

This project will create an inexpensive, non-invasive, stand-alone, 3D printed colour indicating strip (3DCIS) that can be readily incorporated into current wound dressings and used to provide a semi-continuous stream of data regarding the health of a chronic wound. The impact summary below focuses on the users and beneficiaries outside academia and in particular addresses the questions: who will benefit from this research and how?
(1) Chronic wound healthcare workers, such as: clinicians, wound-nurses and district nurses. The 3DCIS technology will allow clinicians to monitor the state of a chronic wound remotely and provide a semi-continuous stream of information that will be mined for trends and used to flag up those of concern for prompt intervention. At present, the only way to check on the state of a chronic wound is to remove the dressing - the 3DCIS technology will reduce significantly this requirement, thereby reducing the number of wound dressing changes and trips made by nurses to patients and patients to clinics. As a consequence, the cost of wound care will be significantly lowered, as almost 80% is associated with that of staff time. The 3DCIS technology promises great savings to the NHS (current cost of chronic wound care: ca. £3Bn pa) and other healthcare services throughout the world. It is also likely to alter wound-care policy and procedures.
(2) Chronic wound suffers. The 3DCIS technology addresses the need for an inexpensive, routine method available for the semi-continuous monitoring of chronic wounds. The simplicity of the technology is such that, even in the absence of a mobile phone with digital camera, the indicators will flag up any concerning high analyte levels and so help inform the patient of the need to contact a wound healthcare worker. Possibly, more importantly, it will also reassure the patient (and healthcare worker) when the wound is satisfactory and doesn't require any intervention. The mobile phone App will help reassure the patient and, via the cloud, inform the clinician in real time as to its condition. This technology empowers the patient and allows them to help in the recovery of their wound. The 3DCIS technology brings an invaluable and new method of clinical analysis to the community in a simple to use and understand, inexpensive form, with the potential to save millions of pounds and improve QOL.
(3) Wound dressing and 3D printing industries. At present there is no simple route to render a chronic wound dressing 'smart'. Any redesign of a wound dressing, so as to embody a wound monitoring method, is likely to add a significant cost and is a barrier to adoption. The 3DCIS technology is stand-alone and readily incorporated into most modern chronic wound dressings and, as a consequence, has the potential to become a global feature of chronic wound dressings, thereby transforming the industry. In addition, the technology can be readily expanded to embrace other analytes, such as volatile sulfide and temperature. The 3DCIS technology, with its 'smart' filament, is new to the 3D printing industry, which itself is emerging as an increasingly important route to mass manufacture, and so will open up a new area of 3D printer product production. Improved products and ranges of goods based on the 3DCIS technology will generate bigger profits and create jobs for all the industries associated with this project.
(4) Other industries. The 3DCIS technology is not limited to just monitoring chronic wounds but could also be used for acute-wound monitoring, e.g. arising from surgery. In addition, many of the indicators generated for monitoring wounds, such as CO2, volatile amine, O2 and H2O, are very relevant to other industries, such as packaging, especially that of food, pharmaceuticals and electronic goods. As a result, the 3DCIS technology is likely to be used by other industries, many of which are significant, and in so doing generate jobs, profits and better products.