Smart Contact Lens Detects Diabetes and Glaucoma – IEEE Spectrum

http://spectrum.ieee.org/nanoclast/semiconductors/materials/smart-contact-lens-detects-diabetes-and-glaucoma

In research described in the journal Nature Communications, the UNIST researchers used graphene-nanowire hybrid films to serve as conducting, transparent, and stretchable electrodes.  Both the graphene and the silver nanowires contribute indispensible properties.

This contact lens should be able to pick up indictors for intraocular pressure, diabetes mellitus, and other health conditions, according to the researchers.
Add some wireless communications and we can have Internet of diagnostivacal contact lenses in the future. 

5 Comments

  1. Tomi Engdahl says:

    Skin-Like Biosensor Offers Needle-Free Blood Sugar Monitoring
    https://spectrum.ieee.org/the-human-os/biomedical/devices/skinlike-biosensor-offers-needlefree-blood-sugar-monitoring

    For people with diabetes, the need to prick fingertips with a lancet every few hours is now over. The advent of sensors for continuous glucose monitoring (CGM) means that patients can read their blood sugar levels in real-time, without the pain and hassles of repeated finger sticks. The latest CGM device, approved in September, doesn’t even require a finger stick for calibration, as other technologies do.

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  2. Tomi Engdahl says:

    Smart Contact Lens Doubles as Blood Sugar Monitor
    https://spectrum.ieee.org/the-human-os/biomedical/devices/smart-contact-lenses-get-practical

    Smart contact lenses with embedded electronics just got a lot more practical. Korean researchers have designed a stretchable contact lens that can monitor glucose without distorting the wearer’s vision, according to a report published today in Science Advances.

    The device contains all the electronic components needed to wirelessly receive power, monitor glucose levels, and generate an LED display, while maintaining the soft, stretchable, and transparent qualities of a contact lens that people might actually be willing to wear

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  3. Tomi Engdahl says:

    Christina Farr / CNBC:
    Alphabet’s Verily says it’s pausing its glucose-sensing contact lens project because, after four years of study, lenses didn’t gauge blood sugar levels reliably

    Alphabet stops its project to create a glucose-measuring contact lens for diabetes patients
    https://www.cnbc.com/2018/11/16/alphabet-verily-stops-smart-lens-glucose-measuring-contact-lens.html

    In a show of transparency, Verily posted a blog post on Friday explaining why it is hitting the pause button on its glucose-sensing contact lens.
    The project was first announced in 2014, back when Verily was known as Google Life Sciences.
    It will shift focus to other eye-related projects, the company said.

    Reply
  4. Tomi Engdahl says:

    Pain-free sensors for diabetics could soon be possible thanks to this new non-invasive method to measure blood glucose.

    Creating a new paradigm of technology
    Driven by its R&D institute, Samsung is set to lead the next century of technological innovation
    https://www.nature.com/articles/d42473-020-00239-0?utm_source=facebook&utm_medium=social&utm_campaign=bcon-samsung_article_1&utm_content=Diabetics

    Reply
  5. Tomi Engdahl says:

    Tech In Plain Sight: Glucose Meters
    https://hackaday.com/2021/10/20/tech-in-plain-sight-glucose-meters/

    If you or someone you know is diabetic, it is a good bet that a glucose meter is a regular fixture in your life. They are cheap and plentiful, but they are actually reasonably high tech — well, at least parts of them are.

    The meters themselves don’t seem like much, but that’s misleading. A battery, a few parts, a display, and enough of a controller to do things like remember readings appears to cover it all. You wouldn’t be surprised, of course, that you can get the whole affair “on a chip.” But it turns out, the real magic is in the test strip and getting a good reading from a strip requires more metrology than you would think. A common meter requires a precise current measurement down to 10nA. The reading has to be adjusted for temperature, too. The device is surprisingly complex for something that looks like a near-disposable piece of consumer gear.

    Of course, there are announcements all the time about new technology that won’t require a needle stick.

    Two Different Kinds

    However you slice it, the real magic is in the test strips. However, how you measure the strip can vary. By far the most common way is to use an amplifier to read the very small currents. However, you can also use precise LEDs and a photodiode — this also requires a very precise current reading, an extra chemical, and precise timing, so you don’t see optical-based meters very often today. The exception is that there are test strips that you can read by simply looking at the color of the strip. This isn’t very accurate, but it is inexpensive and convenient. For most people, the exact blood sugar reading isn’t necessarily as important as knowing if it is normal, high, or very high, for example, so eyeballing the color off a strip is sometimes adequate.

    The usual test strip uses a chemical to react to the blood sample. Each strip type can be different, using a different chemical reaction or a different number of electrodes. However, there are a few common elements.

    First, the strip will use some sort of enzyme that will react with the glucose in the sample and produce something you can detect electronically. Glucose oxidase is the most common choice, although there are other similar enzymes like glucose dehydrogenase nicotinamide adenine dinucleotide or glucose dehydrogenase flavin adenine dinucleotide.

    Over time, blood glucose meters have become more and more sensitive so they require less blood. Less blood means you can use a thinner needle and maybe not set it to go so deep. Anything that can reduce the amount of blood required per test is going to help sell meters to patients. A state-of-the-art meter today might use as little as 300 picoliters of blood. A hungry mosquito will take about 10 microliters, so 300 picoliters is a very tiny amount indeed. In general, capillary action draws a known amount of blood into the strip after you stick your finger.

    A strip may have more than one cell for different purposes. For example, one cell may simply detect that blood arrived at the location, implying that the previous cell should offer a valid reading. Each cell will have at least a pair of electrodes.

    Some meters elect to measure the total electric charge produced by the chemical reaction. Others measure the charge at a particular time in the reaction and use that to deduce the total.

    The test strips, by the way, are where all the money is made since they are disposable. Just like Radio Shack used to give away flashlights to sell batteries, glucose meters are often given away free or sold at very low prices, knowing that you will then need to buy a steady supply of strips to make the meter useful.

    Coding

    Most meters today don’t require coding, but this was common in the past. Different batches of test strips would have different characteristics, so you’d need to enter a code from the strips into the meter to get accurate readings. If you are hardcore, you can also get calibration solutions to test the accuracy of the meter.

    Some meters will use test strips that communicate their code to the meter automatically. T

    High Tech Everywhere

    The technology behind these sensors is relatively recent. The original work dates back to the late 1950s with practical sensors similar to what you see today showing up in the early 1960s. However, the amount of blood required, the accuracy, and — of course — all the microcontroller whiz-bang features have improved over the last half a dozen decades. It is amazing, though, that even after this many years, there hasn’t been a better way found to noninvasively measure blood glucose.

    If I asked you to go to the drugstore and pick up a nanoammeter, you probably wouldn’t have guessed to go to the diabetic testing section. I am somewhat surprised we don’t see more of these meters — or the chips made to drive them — hacked into other instruments

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