In Need of a Glucometer? Your Phone May Soon Be the Solution

From Phone Compass To Glucometer

Monitoring health metrics like glucose levels is often required in many health conditions. This usually requires either lab tests or expensive dedicated medical devices.

This might change thanks to repurposing parts of the now ubiquitous smartphone, according to a scientific paper published by researchers at the National Institute of Standards and Technology in Boulder, USA, titled “Quantitative, high-sensitivity measurement of liquid analytes using a smartphone compass.”

They discovered a way to repurpose the magnetic compass built-in smartphone into a medical device able to measure glucose or pH.

This innovative adaptation of a smartphone relies on hydrogel,  a porous material that swells when immersed in water. The researchers Mark Ferris & Gary Zabow created a custom-design hydrogel with tiny magnetic particles embedded in it.

This hydrogel was engineered so that it would react to changes in glucose concentration or pH (acidity) by shrinking or enlarging. It was done by creating 2 layers of hydrogel, each changing in size at a different rate in response to pH or glucose.

This change of size moves the magnetic particles closer or farther from the phone compass, which can be measured easily by the phone.

Both glucose and pH are important metrics in a wide array of diseases, including diabetes. The method achieved an impressive sensitivity, with the detection of changes as low as a few millionths of a mole (the scientific unit for a certain number of atoms or molecules in a substance), much below the precision required for a proper diagnostic.

The hydrogel can be put into contact with the smartphone through a simple plastic clip-on, and the magnetic field variation can be measured through a simple app. And the plastic clip could even be 3D printed.

Key Advantages Of Phone Glucometers

In itself, this measuring method does not provide a more technically accurate measurement of glucose or pH. But it brings a few key advantages:

• Costs: With smartphones already available, the need for a custom dedicated medical device is removed.
  • In addition, hydrogels like the one used here are inexpensive and easy to fabricate at scale. This should keep the cost of the “cartridge” for measuring glucose low. The researcher estimated the costs of the hydrogel actuators for glucose measurement at $0.16 and for pH at $0.03.
• It also does not require another power source, making it an ideal measurement tool in any situation, from home to office, etc.
• As smartphones are already equipped with connectivity, they can communicate medical data directly to doctors or a health app, providing direct data into digital health systems at no extra costs.
• The extreme sensitivity of the method can allow for a very small sample to be used, making the measurement method less invasive.

Altogether, this could radically change the daily lives of millions of patients, while improving the monitoring and digital data quality about key health metrics.

What’s Next?

Regulation

This innovation must be converted into an easy-to-use glucometer measurement method, which will need to be tested by medical professionals and validated by health safety agencies like the FDA.

While this might be more of a regulatory question than a technical one, it will likely require time and money.

A dedicated software and corresponding ergonomic app able to convert the magnetic measurement into glucose measurement will also need to be developed and equally validated by doctors and regulatory agencies.

Finally, any sharing of the medical data will need to be done in a manner guaranteeing a safe and confidential storage of these data. Any integration with other health monitoring apps or communication with healthcare professionals will face the same requirements.

More Health Measurements

Glucose and pH were used in this study as a proof-of-concept by the researchers, but many other biological metrics could be measured the same way.

For example, the extremely high sensitivity means that glucose could also be measured in saliva, which is much less concentrated than in blood. Combined with the easiness of use of a smartphone, this would make the measurement much less invasive than any current glucometer.

The method could also be used for other molecules.

For example, histamines are usually measured by sophisticated laboratory analysis and require a 24-hour urine collection, but could be measured at home through his new method.

This could also be used with a dedicated hydrogel formula incorporating analyte binding groups. This could make the hydrogel react to relevant targets such as sodium, potassium, lactate, and enzymes.

Improved Hydrogel Detector Design

The bi-layer uniform hydrogel slabs proposed in this study are only one of the options for designing a hydrogel measuring tool.

The researchers propose alternatives like “a buckling motion with a hydrogel pinned at two ends, instead of only at one, may enhance stability”.

A twisting hydrogel motion may allow the field direction to switch from negative to positive, doubling the total possible signal change and increasing the dynamic range if the number of times the field direction switches between each 180° twist of the hydrogel actuator is tracked.

Ensuring that the system detects interference and contaminants that could throw off the measurement will also be important.

Ensuring that the hydrogel has a long shelf life will also be a must for eventual commercial success.

Turning Phones Into Chemical Analysis Tools

Another application of this discovery is going beyond measuring biological parameters. The measurement of pH for example is useful in a blood sample, but be equally useful to measure the pH of water or soil.

This could make this system a powerful alternative to pH test strips used for field pH testing, while offering the measuring precision of a thousand-dollar benchtop meter at a fraction of the cost.

Hydrogel could also be designed to respond to other chemical and physical stimuli such as light, ionic strength, and temperature.

Potential applications are envisioned for home-based quantification of chemical contaminant levels in tap water, for food testing of other opaque liquids such as orange juice, milk, coffee, wine, or soups, and for environmental analysis, such as for analyzing possibly murky lake or stream water in remote locations.

Smartphone-Based DNA Reading?

Further down the road, we can even envision hydrogel utilizing advanced targeting techniques, such as molecularly imprinted polymers and complementary nucleic acid sequences. This would give the hydrogel the ability to react to specific proteins and DNA sequences.

So smartphones could then become able to detect pathogens in air or water, replacing expensive and waste-producing tests like the Covid tests used during the pandemic.

Continuous Monitoring

This study illustrates how smartphones and overall IoT (Internet of Things) will likely revolutionize how we handle medical and chemical measurements in the future.

We are carrying at all times in our pockets a complex electronic device with already built-in extremely sensitive analytical tools, that can be repurposed for new applications.

Glucose measurement is likely going to be one of the first ones, but we can easily imagine a future where we could just put a drop of saliva or breathe on our smartphone, and it would give us biochemical data, pathogens detection, pollution warning, etc.

IoT & Health Sensor Companies

1. Koninklijke Philips N.V.

Philips is a well-known small electronics consumer brand (shavers, electric toothbrushes), equally active in healthcare. It was the #1 for MedTech patent filing in Europe for 2022.

It is active in connected medical products, from wearables to imaging, respirators, or medical robots. The company is also active in semiconductors (including maglev technology) and high-tech/robotics/automation.

Philips’ wearables offer covers cardiac, respiratory, and activity metrics. Its sensors can be integrated into smartwatches, health monitors, medical patches, and activity trackers.

Regarding wearables, Philips favors a partnership solution, where it develops for third parties “their” connected IoT (Internet of Things) medical devices fully compatible with the rest of Philips’ solutions. In that context, it offers its clients prototyping, regulatory advising, end-to-end product development, and industrial-scale production.

The company wants to create a fully integrated digital healthcare environment, where sensors match devices, and then use multiple connectivity solutions to integrate into the Philips HealthSuite Cloud solution and allow for in-depth data analytics.

Because Philips has a history of being able to establish wide-ranging partnerships in health measurement and integrate the data into healthcare SaaS, it could be in a prime position for integrating smartphone-based glucose and pH data as well.

2. Garmin Ltd.

Garmin is a leader in outdoor electronics, with an initial offering of GPS and navigation tools (automobile, marine, and planes), now expanded to fitness and health monitoring.

Fitness represents 23% of the company’s revenues and 10% of operating income, mostly driven by smartwatches. It has shipped 15 million devices in 2022.

Garmin offers a full ecosystem of health data for researchers, helping fields such as research about sleep, depression, cancer treatments, women’s health, or even drowsy driving.

Garmin might not be a tech giant, but it is razor-focused on the outdoor & fitness target, making half of its income beside navigation. This sector is also the main growth area for the company, with the segment most likely to become the main revenue source in the future.

It is likely that health-conscious Garmin users will be interested in monitoring more health parameters thanks to hydrogel-based measurements.

This can be turned into an opportunity by companies like Garmin, in 2 different ways:

• Use a pre-existing compass or integrate a magnetometer into their device to allow for the hydrogel-based measurements to be integrated into their devices.
• Connect their devices to the smartphone to provide an integrated way to visualize the health data from both smartphone and Garmin devices.

The reputation of Garmin for sturdy, high-quality, and useful outdoor products converts well into the fitness and health segment. Interestingly, it leads in the premium segment, with the greatest market share in the >$500 price range, beating Apple here, despite Apple usually dominating the high-price segment of smartphones, computers, and tablets.