NIST researchers develop magnetics-based analyte sensor

In a groundbreaking proof-of-concept study, scientists at the National Institute of Standards and Technology (NIST) harnessed the power of smartphone magnetometers to measure tiny concentrations of important compounds. By combining a smartphone’s built-in magnetometer with hydrogels that respond to specific cues, they achieved remarkable results.

Here’s how it works: Nearly every modern cellphone comes equipped with a built-in compass or magnetometer, which detects Earth’s magnetic field for navigation purposes. However, NIST researchers took this technology a step further. They embedded tiny magnetic particles within a porous material called hydrogel. When immersed in water, the hydrogel swells, and the embedded magnetic particles react to the presence of specific molecules or changes in pH levels.

The implications are significant. Using this approach, the researchers were able to measure glucose concentrations with high accuracy, down to a few millionths of a mole. While such sensitivity might not be necessary for at-home glucose monitoring using blood samples, it could enable routine testing for glucose in saliva, which contains a much lower concentration of sugar. Imagine a future where individuals can diagnose diseases, detect environmental toxins, or even assess the pH of liquids using their smartphones.

The versatility of this magnetics-based sensing platform extends beyond glucose measurement. It opens doors to monitoring other biomedical properties, all while leveraging the ubiquity of cellphones. These “smart” hydrogels, engineered to react to various compounds, offer an affordable and accessible solution for health diagnostics and environmental assessments1.