Smart Sweatbands

If you’ve ever known anyone who has to monitor their blood glucose level, you know it is annoying to have to prick your finger with a lancet to draw blood for each measurement. A new sweatband that incorporates flexible electronics can measure glucose–as well as sodium, potassium, and lactate–from your sweat, without a painful pin prick.

Researchers at the University of California at Berkeley and Stanford announced the band earlier this month. It contains five sensors on a flexible substrate and uses electrical properties to analyze your sweat. For example, more glucose or lactate in your sweat generates more current, while increases in sodium and potassium generate higher voltages. Some of the measurements depend on other factors like temperature, which the band takes into account.

The wearable device communicates with Bluetooth and could find its way into next-generation smart watches and fitness trackers. There’s also a disposable sensor array that goes on like a temporary tattoo.

Not that we haven’t seen glucose tracking on a watch before, but that was just a display. Hopefully, some of the open source glucose monitoring projects will pick up this, or similar, technology. You can see a video about the new sweatband monitor, below.

32 thoughts on “Smart Sweatbands

      1. I’m in the same boat. My only fear is that there will be major push back from big pharma when they attempt to encroach on the sugar monitoring racket. The meters are relatively cheap but the strips are a fat profit for them.

    1. They have been trying to bring something like this to market for over a decade, now. The first attempt involved a watch that had a replaceable pad that came in contact with the skin. You had to replace the pad every so often, though (once or more per day), so it was just as much (or more) a money drain as test strips.

      I’ll believe it when it is actually for sale in my local pharmacy. Something tells me this is going to get bought by Abbot, Bayer, or any other test strip producer and stuck on a shelf until someone finds a cure for Type 1 diabetes that is released to humanity over the internet (because it would be bought by Novo Nordisk or Eli Lilly and shelved indefinitely).

      1. I hate this dumb conspiracy theories. A patent is public, the information can not be hid or “shelved”.

        I worked on a similar project some time ago. The problem was: it just did not work and I learned about some other approaches which also did not work. It is damn difficult to measure the blood glucose non-invasively. There were even some prototypes – lets better say: mock ups for presentations. You can get them cheaply, especially with today’s 3D printing, for meetings with venture capitalists. But then you still need success with the technical development.

      2. There is no financial benefit for a company to shelve this idea. All they need to do is find the right price point. And patents are public and only good for 15 years, so it’s in their own interest to make money from the new tech instead of waiting for the patent to expire and watch someone else take over their business.

  1. There is already this, “a patch device that sticks to the skin of the patient and monitors blood sugar levels every minute and transmits the data wirelessly to a display. ”

    But it needs calibrating, and I suspect that all systems do, so a DIY system could be difficult to set up, even dangerous.

    They go on to admit that “The skin needs to be abraded to remove dead cells. It also only provides a relative measure; you need to calibrate the display with the results of a blood sample in order to get an accurate measure.”

    Perhaps a hack that tapped the wireless data to give you some cross reference to your exercise and food intake data measured on your phone would be safe enough, and very useful. But direct “body hacks” always bother me due the risks.

  2. “For example, more glucose or lactate in your sweat generates more current, while increases in sodium and potassium generate higher voltages.”

    Wait, what? Is the sweat generating electricity? Or have they found a way to break ohm’s law and vary current and voltage independently?

    1. No they have a battery that supply all the electronics. This type of sensors are either voltage source ou current source depending on the concentration of bio marker you are measuring. But this voltage sources have a very( very) high series resistance. Something close to megaohms… so impossible to drawn any power from this. I had the chance to view this article a few months ago before it was accepted. It a nice article but it’s now far from a commercial product. They have huge lifetime and accuracy issues now.

      If some of you want more info on the subject:

        1. Usually it’s both a electro-chemical reaction (slow rate) and a charge displacement (fast rate). For the voltage sources, the sensor are called ISE (Ion selective electrode). It’s an assembly of multiple layer that makes the specific ion going towards an electrode (called working electrode). On the top of this assembly you have a “porous” material that will only let pass the specific ion. When this porous membrane is saturated with ions, there is a (salty) bridge that let run the charges from the working electrode to a reference one. At a given concentration, the electric field through the membrane is linked to the concentration of the solution in contact of the membrane. If you can measure this electric field (voltage), you have the concentration !

        2. For the current source, it’s an other way to mesure the concentration. A technology will work on some ions but not on other ones. If you can’t make ISE for a specific biomarker (ion or a mollecule), you’ll have to use something else, it could be an amperometric sensor or a EIS (Electro-impedance spectroscopy). There are many kind of sensors that could measure biomarker

  3. For those interested in hacking a non-nano version (that’s what the announcement is, that it’s nano/flexible and therefore commercially viable as a wearable), here is some research that isn’t behind a paywall:

    If anyone experienced in biohacking wants to get a project going on .io I’m up for it. I have a wide variety of software/hardware experience and quite a bit of background biochem knowledge but no experience with electrodes or lab chemistry.

  4. The whole pricking the tip of the finger concept is stupid, not only do you have a massive amount of nerves there but you constantly touch things with your fingers. And you blood is the same everywhere so you could prick it somewhere less exposed and sensitive.

    What people don’t do to please the sadistic and/or daft people in the health profession eh.

    1. I see your point, but is there anywhere else that’d be better?

      In their favour, fingers are easy to get to, they lay still, they’re easily accessed by the opposite hand. They don’t bleed much, and stop bleeding quickly.

      Sure it’s a bit hurty but I’m sure you get used to it, people get used to worse. Would be interesting though if you can think of anywhere better, or equally good but less painful.

      1. My daughter (Type 1) uses her fingers, but my buddy’s wife (Type 2) uses her forearm. I’d have thought it wouldn’t be vascular enough there, but she swears by it as just as effective and less painful. My daughter won’t hear of it, though. Personal preference, I guess.

        And I wouldn’t attribute much to sadism or insanity on the part of practitioners – our experience has been that most people who last in health care are truly compassionate and seek to minimize pain while achieving the best outcomes possible. The true sadists quickly find their way into fields without a lot of patient contact. YMMV, of course.

        1. Bit isn’t it daft to make it a rule to make a puncture in the part of the body most exposed to infectious matter? And of course as a policy having bloody fingers (I now it’s tiny, but still) touch things in return can cause health issues for the larger public.
          To me it just lacks logic.
          In my experience having a wound on the finger, say a small cut, is rather annoying, even when it is small and you forget you find yourself exposed to some acidic/alcoholic/etcetera material at some point during the day.
          And if you cook, well you don’t want to have the wound exposed to food, so it’s annoying in that practical sense.

          1. As someone who has used them, no. The lancets are sharpened on an in such a way that they are not so much pins as ‘micro scalpels’. The wound is a straight line less than a millimeter long that starts healing the second it is made. (Though I don’t need a meter anymore, I always have some lancets around, as they are perfect for dealing with slivers/cysts/pimples/etc. because how tiny is the damage that they do to the skin. You can ask at any pharmacy for a few free samples.)

            As well, your skin is very good at defending your body; “Respiratory syncytial virus (RSV), another cold-like virus that can cause serious illness in children, can survive on worktops and door handles for up to six hours, on clothing, and tissues for 30-45 minutes and on skin for up to 20 minutes.” *

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