Nanodiamond Charge Drift Reads Macrophage Inflammation: Chicago and Iowa in Advanced Materials, 4 February 2026

Nanodiamond quantum sensors have been read as thermometers inside living cells for more than a decade. One of them, a 70-nanometer crystal sitting inside a mouse macrophage, drifted downward by 0.27 megahertz over 200 seconds of measurement, which on the usual arithmetic means the cell warmed by 3.62 degrees Celsius. A team at the University of Chicago and the University of Iowa has now put a different quantity behind that same number.

Their paper, Probing cellular activity via charge-sensitive quantum nanoprobes, appeared in Advanced Materials on 4 February 2026, with Uri Zvi as first author and Denis R. Candido at Iowa, Aaron Esser-Kahn and Peter C. Maurer at Chicago as corresponding authors. It was received on 15 March 2025 and accepted on 15 January 2026. The University of Iowa publicized it on 26 August 2026, six months after the article went online, which is why it reaches this Monitor now.

What the zero-field splitting actually tracks, and the dipole term that was being dropped

The sensor is a nitrogen-vacancy center, an atomic defect in diamond whose spin can be initialized with green light, driven with microwaves and read out optically. Each 70-nanometer crystal used here carries roughly 100 of them. The measured quantity is the zero-field splitting, the frequency gap between the spin's ground sublevels, which sits near 2.87 gigahertz and moves by about 74 kilohertz for every kelvin. That temperature coefficient is what turned these particles into intracellular thermometers in the first place.