Fingerprick Blood Sugar Tests: How They Work and Why We Still Use Them

Originally published here: https://mcgill.ca/oss/article/health-technology/fingerprick-blood-sugar-tests-how-they-work-and-why-we-still-use-them

We are living in the future. We have robotic personal assistantswatchesthat replace credit cards, phonesthat recognize our faces, and self driving carsare just around the corner. But for all our advancement, patients with diabetes still need to stab themselves multiple times a day to check their blood glucose levels. There has to be a better way, right?

The history of glucose meters starts in 1956 with Leland Clark presenting a paper on an oxygen electrode, later to be renamed after him. Six years later the Clark electrode had been developed, with the help of Ann Lyons, into the first glucose enzyme electrode. These early glucose meters were large, bulky and only used in hospitals. It wasn’t until 1981 that at-home monitors were popularized, sold on the market by the same names you’d recognize today: Glucometer and Accu-chek.

These glucose meters worked by a method still used today that’s quite similar to how breathalyzers detect blood alcohol content. Electrons are transferred from the glucose in blood through molecules until it reaches the electrodes in the glucometer. These moving electrons create an electrical current proportional to the amount of glucose in the blood, and the number appears on the monitor.  

But what if we could measure our blood sugar without having to prick our fingers?

A lot of research and development has gone into that very idea.

Instead of measuring the glucose in blood directly, attempts have been made to measure the glucose in other fluids. Urine tests have been available for much longer than even blood tests but visiting a bathroom every time you need to test your sugar is far from ideal as those with type 1 diabetes may need to test their sugar up to 12 times a day!

New technologies are looking at using tears. Since these fluids are naturally external to the body their measurement needs no needles, something that would decrease the cost of testing and likely increase the reliable tracking of patients’ blood sugar.

Google notably prototyped a contact lens in 2014 that would contain the chips and sensors to measure sugar levels and either change colour accordingly, or transmit that data to an external device. Because of the low volume of tears, the lenses need to be exceptionally accurate. Reliable relationships between the glucose in tears and in blood need to be established and contact lens solution that doesn’t inhibit the lenses needs to be developed.

A few other technologies have been investigated for non-invasive blood sugar testing. A device using near-infrared spectroscopy that would shine light through the earlobe to sense glucose was prototyped, but required a lot of measurements (like earlobe width and blood oxygen levels) to calibrate (though a similar product has been sold outside of the US and Canada). Scientists have attempted to create devices that would pull glucose out from the blood through the skin, using chemicals or electrical currents, as well as devices that would measure blood sugar via polarized light measurements, but at least as of yet, none of these devices have been commercially available in Canada. 

One product that may soon be seen on market is Glucair, which functions similarly to a breathalyzer. It analyzes the acetone present in your breath to take a measurement of your blood glucose level. This system could be made quite small, like modern breathalyzers, and would require no finger pricking or needles of any kind. 

For now the best alternative to finger prick tests are continuous glucose sensors. They consist of a needle that is embedded in the skin that can take blood samples very often, and the circuitry to measure the glucose content. The results are seen by scanning the sensor with a receiver, a smartphone, or via bluetooth connection. They give live results and can last up to 7 days, but tend to be very expensive, given the disposable nature of the inserts, and aren’t always covered by insurance like glucometers are. 

In Canada there are a few neat options available. The Freestyle Libre is what’s called a flash glucose monitoring system. The small sensor is inserted into the skin and worn for 14 days, and can be scanned whenever needed by the receiving decide to get blood sugar levels. The Dexcom G5 is also a small sensor that can be worn for 10-15 days, but it transmits wirelessly to your smart devices. This makes it especially useful for parents or caretakers wanting to monitor someone else’s glucose levels.

(Click here to view a higher resolution version of this image)

Continual monitoring allows greater accuracy in insulin doses and allows a patient to provide more information about their blood sugars to their doctors. Ideally continual sensors will also be able to communicate directly with insulin pumps, so that type 1 diabetics can receive their correct dose without needing to finger prick first.

Considering how far we’ve come since the advent of blood glucose monitoring in the 1960s, I have faith continuous and non invasive technologies are coming. It’s really just a question of how many needles diabetics will have to endure before they do.

Space Based Solar Power

Originally published here: https://mcgill.ca/oss/article/did-you-know-technology/space-based-solar-power

There are certain problems with solar power technologies that still need some work. We are addressing quite a few bumps on the road to completely sustainable energy though. High costs of solar cells are being brought down by green energy rebates and tax exemptions. Inflexible and delicate solar panels are being subbed out for durable ones that can be used to make roadsor roofs, and the ever-present climate change deniers that resist solar power’s implementation are a slowly dying breed. But 1 big issue still arises- how do we get more power from the sun?

Space-based solar power is a developing technology that may just help us get more bang for our solar bucks. Due to the atmosphere of Earth, 55-60% of solar power is lostbefore it ever reaches the stratosphere, and due to the Earth’s rotation, another 10-25%of solar energy is lost if panels aren’t set up with a tracking system, to stay pointed at the sun. Not to mention the fact that solar panels are virtually useless at night. By putting solar panels into space, they would be exposed to light for almost 100% of a day, versus the 29% the average panel gets on Earth, and the panels wouldn’t need to be protected from storms, animals or even humans. It’s even possible that placing solar panels into space could help limit the solar radiation reaching Earth, thereby reducing the effects of global warming.

But there are a few major hold ups for this technology, namely, putting things into space. Satellites are incredibly expensive (50 million on the cheaper end), and though they may take less damage when in space, they could not simply be services when damage does occur. There’s also a notable problem of how to transmit the energy back to Earth. Solar panels on the ground convert photons into moving electrons and send them down wires to where they’re needed, but we can’t very well wire from space to the power plants. Ideas on multi-step processes involving photons becoming electrons becoming photons becoming electrons have been examined, but at each stage, energy would be lost.

Alas, don’t expect to be powering your microwave from space energy soon, though do join me in holding out hope for this decidedly futuristic technology!

Dentists can treat cavities without using a drill

Originally published here: https://mcgill.ca/oss/article/did-you-know-health/did-you-know-dentists-can-treat-cavities-without-using-drill

If you are not a big fan of the anesthetizing and drilling part of getting a cavity filled, you’re far from alone. 

What if your dentist could apply a gel to your cavities (or dental caries) that would soften necrotic tissue but leave your healthy dentin alone, allowing the affected tooth tissue to simply be scooped out? 

So-called chemomechanical methods of removing cavities are not new. They were initially marketed in the 1970s, but their original designs had some serious problems. Caridex was one of the first, but it required heat, specialized equipment, large volumes of product (200-500 mL) and tasted bad. 

Luckily the creators of Carisolv were able to address many of these issues. Carisolv contains three different amino acids that can interact with the collagen that makes up dentin. Degraded collagen allows these amino acids to enter its structure and bind to it, softening it, while healthy collagen is unaffected. Only a few drops need to be applied to a tooth, and after a minute or so the softened dentin can be scraped away using a special tool. 

Another product, Papacarie uses a slightly different approach to dissolve diseased dentin. Papacarie contains papain, an enzyme that can break down collagen. However, healthy tooth tissue contains an enzyme that will render papain useless, ensuring that only carious tissue is dissolved. Papacarie is applied to an affected tooth and left for about 30 seconds, after which the cavity can be scraped out using a normal dental spoon. 

Both of these methods have the benefit of indicating when there is no more diseased dentin via a colour change. However, their major downfall is the time it takes to use them. Studies have shown that the traditional manual method of cavity removal is much faster (3-4 minutes) than chemomechanical methods (8-9 minutesfor Carisolv, 6-7 minutesfor Papacarie). However, studies have also shown that chemomechanical methods are more effectivethan traditional methods at preserving healthy dentin. 

Dr. Grant Ritchey, dentist and contributor to Science Based Medicine, explained to me via Twitter that chemomechanical caries excavation could be fantastic for use in patients with teeth resistant to anesthesia, children, or those with anxiety surrounding dental drills, as well as for cavities small enough to make freezing and drilling a hassle.

I’m looking forward to seeing this technology develop further and seeing its integration into more and more dental practices.