The US government’s National Institute of Standards and Technology (NIST) has announced that their researchers have come up with a technique for measuring blood glucose concentration accurately through a magnetometer on a regular smartphone.

Today's mobile phones are almost all equipped with a magnetometer, or built-in compass, that detects the Earth's magnetic field and provides important navigational data.

These built-in magnetic compasses, when used alongside magnetic materials designed to shift their structure in response to biological or environmental stimuli, have the potential to quickly and inexpensively measure several other biomedical qualities to monitor or diagnose illnesses, and even identify environmental toxins, according to NIST scientist Gary Zabow.

In their proof-of-concept study, the researchers strapped a hydrogel strip and a tiny well with a solution – which is used in place of blood for testing – to a cellphone. (Hydrogel is a porous substance that swells when put in water.) After creating a hydrogel that would expand and contract in response to glucose or pH levels, they additionally inserted small magnetic particles into the material. Any resulting pH level variations may be indicative of a number of biological disorders.

Also, they reported that the smart hydrogels they built are rather simple to make and reasonably priced. Theoretically, these might be offered as inexpensive test kits that could be connected to a phone in order to measure blood sugar using a specific app, because they make no use of electronics or technology beyond what is contained in a smartphone.

In the future, efforts to use mobile magnetometers to increase the accuracy of such measurements may be able to detect compounds involved in the immunological response of the body, such as histamines, DNA strands, and certain proteins, at concentrations as low as a few tens of nanomoles (billionths of a mole).

The researchers reported their findings in the March 30, 2024 edition of Nature Communications.