Liam T. Hall

Quantum measurement and orientation tracking of fluorescent nanodiamonds inside living cells

Fluorescent particles are routinely used to probe biological processes. The quantum properties of single spins within fluorescent particles have been explored in the field of nanoscale magnetometry, but not yet in biological environments. Here, we demonstrate optically detected magnetic resonance of individual fluorescent nanodiamond nitrogen-vacancy centres inside living human HeLa cells, and measure their location, orientation, spin levels and spin coherence times with nanoscale precision. Quantum coherence was measured through Rabi and spin-echo sequences over long (>10 h) periods, and orientation was tracked with effective 1° angular precision over acquisition times of 89 ms. The quantum spin levels served as fingerprints, allowing individual centres with identical fluorescence to be identified and tracked simultaneously. Furthermore, monitoring decoherence rates in response to changes in the local environment may provide new information about intracellular processes. The experiments reported here demonstrate the viability of controlled single spin probes for nanomagnetometry in biological systems, opening up a host of new possibilities for quantum-based imaging in the life sciences.

Magnetic spin imaging under ambient conditions with sub-cellular resolution.

The detection of small numbers of magnetic spins is a significant challenge in the life, physical and chemical sciences, especially when room temperature operation is required. Here we show that a proximal nitrogen-vacancy spin ensemble serves as a high precision sensing and imaging array. Monitoring its longitudinal relaxation enables sensing of freely diffusing, unperturbed magnetic ions and molecules in a microfluidic device without applying external magnetic fields. Multiplexed charge-coupled device acquisition and an optimized detection scheme permits direct spin noise imaging of magnetically labelled cellular structures under ambient conditions. Within 20 s we achieve spatial resolutions below 500 nm and experimental sensitivities down to 1,000 statistically polarized spins, of which only 32 ions contribute to a net magnetization. The results mark a major step towards versatile sub-cellular magnetic imaging and real-time spin sensing under physiological conditions providing a minimally invasive tool to monitor ion channels or haemoglobin trafficking inside live cells.

Dynamical decoupling of a single-electron spin at room temperature

Here we report the increase of the coherence time T

Sensing of fluctuating nanoscale magnetic fields using nitrogen-vacancy centers in diamond

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Monitoring ion-channel function in real time through quantum decoherence

of a single electron spin at room temperature by using dynamical decoupling. We show that the Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence can prolong the T

High spatial and temporal resolution wide-field imaging of neuron activity using quantum NV-diamond

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Detection of atomic spin labels in a lipid bilayer using a single-spin nanodiamond probe

of a single Nitrogen-Vacancy center in diamond up to 2.44 ms compared to the Hahn echo measurement where T

Ambient nanoscale sensing with single spins using quantum decoherence

_2 = 390 \mu

Ultrasensitive diamond magnetometry using optimal dynamic decoupling

s. Moreover, by performing spin locking experiments we demonstrate that with CPMG the maximum possible

Nanoscale magnetometry through quantum control of nitrogen-vacancy centres in rotationally diffusing nanodiamonds

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