More Medical Tech –Smart Bandages for Wound Management

I have a bias (as you may have noticed) for solutions in a domain that take advantage of technology but are developed within that domain. A recently example is intelligent bandages, developed at Massachusetts General Hospital, Harvard, Purdue and several other research centers. The purpose of such a bandage is to monitor a wound as it heals and in some cases to improve healing. (I should add there are lots of applications for smart bandages in monitoring other aspects of health. Here I’m only touching on wound care and prevention.)

Monitoring can take many forms – one application is simply to determine levels of oxygenation around the wound site. Healing requires large levels of oxygen; any shortfall will slow healing or lead to tissue death. That creates two interesting constraints for a bandage; it must be flexible and it must be permeable to oxygen (just like a Band-Aid™). A method to display oxygen concentration in wounds using phosphorescent bandages has already been demonstrated; presumably this could easily be adapted to deliver digital information. An even more interesting prototype not only detects low levels of oxygen but also uses this to trigger a chemical reaction in the bandage which then generates oxygen – a beneficial chemical feedback loop.

Some of these prototypes are currently half an inch thick and six to eight inches long – not quite the thin bandages we think of today, but no doubt this will improve with time. The intelligent part (processing and communication) is, area-wise, actually a very small part of the bandage; the bulk is sensing and chemistry. The chemistry can be further extended – some researchers have shown the ability to deliver pain and anti-bacterial medications directly from the bandage, also though a feedback loop or through wireless control.

A very interesting application is to minimize scarring as the tissue heals. Scars have psychological impact but can also be physically-limiting when new skin stretches too tight around the eyes, mouth and other areas. Intelligent bandages can help by controlling growth through a matrix which guides that growth. Current research uses nano-fibers and similar materials to prompt this growth. There is also a protein called fibronectin which can accelerate growth; initial experiments based on embedding this in the bandage are promising and appear to encourage growth of soft skin (unlike typically taut scar tissue). I would imagine (without proof) that selective electrical stimulation may also be helpful in guiding skin growth.

Another quite different application is to detect early development of bedsores. These start under the skin as a result of prolonged pressure on one area, limiting blood supply to that area. A challenge for doctors is that bedsores cannot be detected until they reach the surface of the skin, by which time it is usually too late to take corrective action. A Berkeley group detects potential problems using impedance measurements through the skin and into underlying tissue, driven by electrodes printed onto a flexible patch. The current technology seems to be just the electrode array but you could easily imagine automation being added.

Most of this work is very much still in the research stage. Perhaps the biggest part of the problem is the complexity of wound biology and the many different factors that must be considered, monitored and addressed: bacterial infections, immune response, oxygenation and skin re-growth. There are plenty of challenges and opportunities for tech in this area that go well beyond the health monitors we think of today.

You can read more about oxygen detection in wounds HERE, intelligent bandages HERE (ACM paper – may require membership or purchase) and HERE. There’s a good video from Science Nation on the topic HERE. The Berkeley application for bedsores is HERE.

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