title: Quantum measurement and orientation tracking of fluorescent nanodiamonds inside living cells.
abstract: 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.
authors.affiliation: School of Physics, University of Melbourne, Victoria 3010, Australia.
authors.forename: L P
authors.initials: LP
authors.lastname: McGuinness
authors.forename: Y
authors.initials: Y
authors.lastname: Yan
authors.forename: A
authors.initials: A
authors.lastname: Stacey
authors.forename: D A
authors.initials: DA
authors.lastname: Simpson
authors.forename: L T
authors.initials: LT
authors.lastname: Hall
authors.forename: D
authors.initials: D
authors.lastname: Maclaurin
authors.forename: S
authors.initials: S
authors.lastname: Prawer
authors.forename: P
authors.initials: P
authors.lastname: Mulvaney
authors.forename: J
authors.initials: J
authors.lastname: Wrachtrup
authors.forename: F
authors.initials: F
authors.lastname: Caruso
authors.forename: R E
authors.initials: RE
authors.lastname: Scholten
authors.forename: L C L
authors.initials: LC
authors.lastname: Hollenberg
mesh_terms: D002460:Cell Line; D003593:Cytoplasm / Q000378:metabolism; D018130:Diamond / Q000737:chemistry; D005453:Fluorescence; D006367:HeLa Cells / Q000378:metabolism*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008280:Magnetics / Q000379:methods*; D015336:Molecular Probe Techniques / Q000295:instrumentation*; D058612:Nanodiamonds / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods; D009584:Nitrogen / Q000737:chemistry*; D010316:Particle Size; D045663:Quantum Dots; D011789:Quantum Theory
chemical_list: D058612:Nanodiamonds; D018130:Diamond; D009584:Nitrogen