Mouth Sensor Can Measure the Salt in Every Potato Chip You Eat

People with high blood pressure could get real-time data about sodium intake

3 min read
Close up photograph of a man eating a potato chip.
Photo: iStockphoto

If you’re one of the approximately 36 million adults in the United States with high blood pressure (also called hypertension), your doctor may have lectured you about the importance of reducing your sodium intake. Maybe you listened, and maybe you even intended to follow your doctor’s advice.

But sodium, the primary component of table salt, is everywhere in our modern diets—in snack foods, in restaurant meals, even in beverages—and your good intentions probably didn’t get you very far. 

To tackle this problem, researchers at the Georgia Institute of Technology have invented a flexible electronic sensor that can be embedded in a dental retainer for real-time monitoring of sodium intake. The device, which they described in the journal PNAS, could send info to your phone, giving you instant data about whether you’re busting your low-sodium diet.

Whether you decide to change your diet based on that data is another question entirely. But getting the data is the first step. 

W. Hong Yeo, an assistant professor of micro and nano engineering who led the research team, says it would also be possible to stick the sensor directly to the tongue or the roof of the mouth, or to laminate it onto a tooth. The soft retainer they used in this experiment was just phase one. “For the first prototype device, we wanted to offer easy handling and cleaning capability via the integration with a soft retainer,” he said.

Yeo says the biggest challenge was making the entire electronic device soft, flexible, and comfortable enough to wear in the mouth. So the team designed a chip that uses stretchable circuits mounted on an ultrathin porous membrane.

Illustration of the sensor. A new wireless sensor made of stretchable circuits mounted to a porous membrane can measure how much sodium a person eats in real time. Image: Georgia Institute of Technology

Its power source is a rechargeable micro-coin battery (measuring 6.8 mm in diameter), which could continuously monitor real-time sodium intake for 12 hours. Yeo thinks that’s a long enough battery life for practical use, as a wearer could put in the retainer just at meal times and recharge it at night. But his team is considering removing the battery in the design of an even smaller sensor, which could receive power from an external source via inductive coupling.

The sodium sensor itself uses inexpensive materials that respond to the presence of sodium ions. To test the gadget, Yeo’s team first had people take sips of water with various concentrations of salt. When it proved adept at measuring those sodium levels, they moved to a harder challenge: real food and drink. The test subjects took a gulp of veggie juice, slurped up a mouthful of chicken noodle soup, and crunched down on a potato chip.

The device did well with the juice and soup, but the chip was a little trickier. The measurement of its sodium level showed an initial spike, caused by the chip physically hitting the sensor, and the reading was significantly off from the actual sodium value, a discrepancy Yeo chalks up to dilution from saliva.

But both these issues can be addressed by good data processing, he says. If the software system is calibrated with the user’s baseline sodium levels, it could remove spikes and outlier readings. And it could be connected to an existing health or fitness app (such as MyFitnessPal) that contains info about the sodium content of millions of different food items—including potato chips

The team has already created an Android app, and the sensor uses Bluetooth to send its data to a smartphone or tablet. While Yeo says his team is working to miniaturize the device further, he thinks it’s nearly ready for practical use. “It’s very close to commercialization, it just depends on companies coming and expressing interest,” he says. 

The data is out there. Whether medical device companies decide to act on it—or people choose to make dietary changes based on it—is another question entirely. 

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This CAD Program Can Design New Organisms

Genetic engineers have a powerful new tool to write and edit DNA code

11 min read
A photo showing machinery in a lab

Foundries such as the Edinburgh Genome Foundry assemble fragments of synthetic DNA and send them to labs for testing in cells.

Edinburgh Genome Foundry, University of Edinburgh

In the next decade, medical science may finally advance cures for some of the most complex diseases that plague humanity. Many diseases are caused by mutations in the human genome, which can either be inherited from our parents (such as in cystic fibrosis), or acquired during life, such as most types of cancer. For some of these conditions, medical researchers have identified the exact mutations that lead to disease; but in many more, they're still seeking answers. And without understanding the cause of a problem, it's pretty tough to find a cure.

We believe that a key enabling technology in this quest is a computer-aided design (CAD) program for genome editing, which our organization is launching this week at the Genome Project-write (GP-write) conference.

With this CAD program, medical researchers will be able to quickly design hundreds of different genomes with any combination of mutations and send the genetic code to a company that manufactures strings of DNA. Those fragments of synthesized DNA can then be sent to a foundry for assembly, and finally to a lab where the designed genomes can be tested in cells. Based on how the cells grow, researchers can use the CAD program to iterate with a new batch of redesigned genomes, sharing data for collaborative efforts. Enabling fast redesign of thousands of variants can only be achieved through automation; at that scale, researchers just might identify the combinations of mutations that are causing genetic diseases. This is the first critical R&D step toward finding cures.

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