School of Physics, University of Melbourne, Victoria 3010, Australia.
Nat Nanotechnol. 2011 May 8;6(6):358-63. doi: 10.1038/nnano.2011.64.
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.
荧光粒子通常被用于探测生物过程。单个荧光粒子内的单自旋量子特性已经在纳米磁强计领域得到了探索，但尚未在生物环境中得到探索。在这里，我们在活的人类 HeLa 细胞内演示了单个荧光纳米金刚石氮空位中心的光探测磁共振，并以纳米级精度测量了它们的位置、方向、自旋能级和自旋相干时间。通过长 (>10 h)时间的拉比和自旋回波序列测量了量子相干，通过 89 ms 的采集时间以有效的 1°角度精度跟踪了方向。量子自旋能级作为指纹，允许具有相同荧光的单个中心被识别和同时跟踪。此外，监测局部环境变化引起的退相干速率可能会提供关于细胞内过程的新信息。这里报道的实验证明了在生物系统中进行纳米磁强计的受控单自旋探针的可行性，为生命科学中的基于量子的成像开辟了许多新的可能性。
