Smartphone magnetometer measures compounds important for health

This is the claim of researchers at the US National Institute of Standards and Technology (NIST), who said the same technique, which uses the magnetometer in conjunction with magnetic materials designed to change their shape in response to biological or environmental cues, could be used to measure other biomedical properties for monitoring or diagnosing human disease.

The method also has the potential to detect environmental toxins, said NIST scientist Gary Zabow.

In their proof-of-concept study, Zabow and fellow NIST researcher Mark Ferris attached a well containing the solution to be tested and a strip of hydrogel - a porous material that swells in water – to a smartphone.

The researchers embedded magnetic particles within the hydrogel, which they had engineered to react to the presence of glucose or to pH levels by expanding or contracting. Changing pH levels can be associated with a variety of biological disorders.

As the hydrogels enlarged or shrunk, they moved the magnetic particles closer to or farther from the smartphone’s magnetometer, which detected the corresponding changes in the strength of the magnetic field.