I’ve talked about wearable tech before, but there’s a lot of research going on in this area. Why? Because flexible, wearable, maybe cheaper tech is always a good thing, especially in the medical field. If you’ve not had to be in hospital before, first let me congratulate you and hope you don’t end up there for something serious, and second, telemetry is a big thing. Your vital stats are continually monitored so you don’t end up, well, dead at worst. Heart rate, blood pressure, fluid intake, and so forth. There’s also some other body information that your doctor may want to get out of you apart from vitals, depending on what you’re in for. Maybe you’re in physical therapy and your doctor wants to check how you’re healing based on your range of motion, for example.
See, medical telemetry exists, although there are quite a few issues to deal with. One of the big ones is that there are some instruments that are only good at one thing only, but that’s because their circuitry is optimized to only do that thing. In other words, to monitor heart rate, blood pressure, temperature, and so on, one may be hooked up to just one computer, but you need several different probes running at the same time. That’s a lot of wiring, and I’m not sure how comfortable you’d be if you’re somewhat aware that you look like a laid-out marionette.
Not to mention all those wires could get caught in other things, including tubes that can hurt like crazy and shoot out blood everywhere when they’re violently ripped out of your body. I’m going to stop imagining scenarios here now, we’re going back to science.
There’s an entire field of research based on the idea of the ‘lab-on-a-chip‘, essentially devices that can do more than one thing at a time, even measure more than one thing at a time. Why not do that with wearables, then? It’s just printing circuits on some kind of plastic film, really. A study out of Osaka Prefecture University aims to do just that: a multifunctional device that’s also flexible so it’s more comfortable. Yamamoto et al. created what is essentially a plastic slap-patch with sensors for skin temperatures, ECG, UV, and an three-axis accelerometer to monitor motion. The ECG part got my attention, because if you’ve ever seen anyone get hooked up to an ECG, you know that’s a lot of wiring already.
Cut down on the wiring, maybe it’ll be cheaper. The circuitry is printed on a polyethylene terpthalate surface; you know this as PET, and it’s easily recyclable (the authors claim it’s disposable, but there’s got to be a way to recycle it safely, right?). However, the film is going to have to strike a balance between flexible and won’t tear apart, because PET is not exactly flimsy.
Enter then, the art of kirigami. Related to origami, kirigami literally means ‘cut paper’, or rather the art of cutting paper. Where’s the art in that? Simple: after making a few folds, you cut some patterns into your paper. When you unfold, you get some really nifty designs. You’ve been doing this with paper snowflakes, but if you happen to be Hans Christian Andersen, you can probably do this:
(by the way, if you are Hans Christian Andersen, please come by the sci.casual offices – we’d really like to talk to you, considering that you’ve been dead for almost 150 years)
The authors assert that the kirigami-style sheet allows the device to be more flexible, which makes sense if you’ve ever stretched cut-paper art before – it can’t stretch too far, but you don’t really need it to be too flexible on skin anyway. All of the necessary circuitry was either printed or deposited onto the film. Now for the important question: does it work?
It works, otherwise it wouldn’t have been published (I’ve got some thoughts on this that I’d like to talk about later) of course. It’s still going to need some wiring (probably to hook up to a computer and for power), but one or two wires certainly beats, well, maybe six or ten. So it’s really possible to make small, flexible instruments that can cut down the number of materials you need, which means less materials for production and disposal, less things to connect and disconnect (good for life-and-death emergency situations, that’s for sure), and if nothing else, this study could also give others similar ideas for improving flexibility for similar medical instruments by making strategic cuts in the fabric or film. You’ve done this with your jeans in the 90s, anyway.
Featured Article: Yamamoto Y, Harada S, Yamamoto D, Honda W, Arie T, Akita S, Takei K. (2016) “Printed multifunctional flexible device with an integrated motion sensor for health care monitoring.” Science Advances 2. doi: 10.1126/sciadv.1601473
Featured Image Credit: Wikimedia Commons/Flickr (CC-BY-SA-20), Author: Bharath Kishore (2011)