A CMOS NMR needle for probing brain physiology with high spatial and temporal resolution

Magnetic resonance imaging and spectroscopy are versatile methods for probing brain physiology, but their intrinsically low sensitivity limits the achievable spatial and temporal resolution. Here, we introduce a monolithically integrated NMR-on-a-chip needle that combines an ultra-sensitive 300 µm NMR coil with a complete NMR transceiver, enabling in vivo measurements of blood oxygenation and flow in nanoliter volumes at a sampling rate of 200 Hz. A miniaturized NMR-on-a-chip needle can be implanted into rodent brains and can measure blood flow and oxygenation changes in vivo in a small volume at an unprecedentedly high temporal resolution of a few milliseconds.