Paper-based detection device for chronic wound monitoring

Background: Chronic wounds are wounds that are impeded at a certain recovery stage and cannot proceed through a normal healing process. They account for an annual wound care expenditure of approximately 5–10 billion dollars. Among all potential patients, the elderly are the most vulnerable population for chronic wounds. Older patients, however, present several issues that must be addressed in order to provide suitable chronic wound diagnosis and care monitoring. Here, we discuss our development of a paper-based detection device that can serve as a rapid, inexpensive, convenient, and sensitive chronic wound assessment tool for providing better chronic wound-monitoring platform among the elderly. Methods: Our paper-based detection device primarily comprises two parts: a test zone made of chromatography paper, and a passage zone made of Whatman filter paper. In this design, our targeted protein, human neutrophil elastase (HNE), reacts with a pre-impregnated substrate to produce a visible and measurable colorimetric reaction (from colorless to light yellow). An image of the results can be captured with a smart phone camera, and converted to the blue color range using ImageJ software to quantify the mean HNE intensity, defined as test zone intensity minus blank zone intensity. Results: Our tool produced colorimetric responses using samples from a total of 8 patients, and mean HNE intensities were calculated. Conclusions: Our paper-based device is designed to be a user-friendly, inexpensive, rapid, and accurate chronic wound assessment platform that can be applied to elderly healthcare and long-term care at home. It can provide for better healthcare outcomes via early chronic wound detection, decreased medical costs, and reduced clinical visit time, all of which would be particularly impactful for the elderly.