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

慢性伤口被称为“沉默的流行病”，在其一生中影响着相当大比例的人口，1-2%。慢性伤口的主要原因是：糖尿病、烧伤和压疮，正如术语“慢性”所暗示的那样，它们并不容易治愈。因此，在最近的一项研究中，近42%的腿部/足部溃疡在过去6个月内没有愈合，28%的腿部/足部溃疡已经一年或更长时间没有愈合。在所有国家，慢性创伤护理给地方和国家卫生服务带来了相当大的负担。例如，在英国，约有650000名患者患有某种形式的慢性伤口，导致每年的成本约为3Bn，而在美国，约有650万患者，其治疗费用约为25Bn pa。静脉性溃疡通常发生在腿部，占慢性伤口的70%-90%，主要影响老年人。由此得出的结论是，由于全球平均预期寿命持续增长，那么治疗慢性伤口的发病率和费用也将增加。英国国民健康保险制度每年的治疗总费用约为30亿英镑。显然需要一种廉价的一次性伤口监测方法，该方法可以：(I)容易地结合到伤口敷料中，从而使其变得智能，以及(Ii)能够向临床医生、护士和患者提供关于关键生物标志物的连续或半连续信息流，即生化线索，其将帮助识别伤口的状况/状态，从而标记未正确愈合和需要医疗干预的伤口。这项拟议的技术涉及3D打印多分析物条，由四种不同颜色的指示剂组成，这些指示剂根据四种不同的气体生物标志物进行选择，即：二氧化碳、挥发胺(RNH2)、湿度(H2O)和氧气。该条将提供半连续的、按需的信息流，该信息流涉及伤口上方和敷料所包含的顶腔的组成。与现有的伤口监测方法相比，这种简单的、独立的、彩色试纸提供的多分析、原位、挥发性分析具有许多优点，包括：(1)使用3D打印技术生产完整的试纸，(2)可由眼睛或数码相机读取的简单颜色变化，(3)简单地结合到现有伤口敷料中(即独立的)，(4)易于解释，(5)记录的数据趋势和自动实时警报(6)便宜，(7)非接触/非侵入性，(8)适用于广泛的医疗保健环境(包括：护理地点、门诊、医院病房和家庭护理)，(9)在其他领域的应用范围，包括医疗领域，如急性伤口敷料，以及非医疗领域，如食品和电子产品包装，(10)适用于微制造，以及(11)添加其他分析的范围，如温度和挥发性硫化物。

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.