Diamond Sensor Catches Magnetic Signal from a Living Cell ⚡ экспресс
Optical tweezers paired with fluorescence microscopy are widely used for single-cell analysis, but fluorescence is hampered by blinking, photobleaching, and autofluorescence from biological tissues. An alternative approach has been developed: quantum magnetometry based on nitrogen-vacancy (NV) centers in diamond is integrated into the optical tweezer system. This enabled precise trapping and manipulation of individual cells in a microfluidic environment while simultaneously recording their magnetic response. The magnetic signal from a cell labeled with magnetic nanoparticles was 89 µT, whereas the noise level of unlabeled cells was 3.9 µT. The method overcomes the limitations of fluorescence, providing high-precision detection of single cells. The platform holds promise for studying cellular activity in biological microenvironments, for example in disease diagnostics or cell sorting.
Biologists often tag cells with glowing molecules — it's like searching for a dim light in the smoke. The light quickly fades, and the smoke creates interference. Scientists replaced this approach with a magnetic compass: the cells received tiny magnetized particles, and the signal is read by a diamond sensor with NV centers in a carbon matrix — artificial defects that, like a compass needle, respond sensitively to magnetic fields. The sensor is placed in optical tweezers — a laser beam that holds cells in a stream of liquid without contact — and measures the deflection of the magnetic 'needle'. Even a single tagged cell generates a clear signal of 89 microtesla with noise of just 3.9 — as if a compass picks up the breath of a tiny magnet. Amazingly, the diamond sensor is so sensitive that it can detect the magnetic field of a single electron — no bulky equipment is needed. This 'magnetic eye' paves the way for diagnosing diseases right inside the body, tracking changes in real time.
🎯 Diamond NV centers are engineered defects: a nitrogen atom sitting next to a vacancy in the crystal. Their sensitivity can capture the magnetic field of a single electron from several nanometers away.
🎬 This precision brings us closer to sci-fi medical scanners — like the tricorder from Star Trek, which diagnoses diseases one cell at a time.