Diamond sensor picks up the heart's magnetic signals ⚡ экспресс
Researchers have used quantum sensors based on NV centers (nitrogen defects in diamonds) to contactlessly record the heart’s magnetic signals, known as magnetocardiography (MCG). In experiments with varying levels of shielding—and even without it—the signals were averaged over hundreds of heart cycles. With a sensitivity of 6–26 pT/√Hz in an active volume of less than 0.5 mm³, these sensors already hint at the possibility of detecting a single heartbeat. A key step toward clinical use is NV-center gradiometry: just as two microphones cancel out common noise, two tiny sensors suppress external magnetic interference. This paves the way for portable MCG and magnetic encephalography.
A tiny defect in diamond is like a microscopic ear, able to pick up the magnetic 'breath' of the heart. Such sensors work at room temperature and are no bigger than a grain of sand.
To hear a faint signal in a noisy room, engineers used two sensors: just as our ears compare sound to discern speech, a pair of diamond 'ears' subtracts the magnetic background. This made it possible to record a magnetocardiogram without bulky shielding.
The irony is that the sensor is not a perfect diamond, but its flaw—a nitrogen atom next to a vacancy in the lattice. It is precisely this defect that, under the light of optical spectroscopy, turns into a supersensitive element. In the future, such sensors could form the basis of contactless diagnostic patches—cheaper and more portable than traditional magnetometers.
🎯 The heart's magnetic pulse was first captured in 1963—the setup was the size of a car and required expensive magnetic shielding.
🎬 The medical tricorder from Star Trek is closer than it seems: a compact diamond sensor reads magnetic rhythms without contact.