Nanomechanical Sensing Using Spins in Diamond
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By creating atomic-scale defects in nanoscale slivers of diamond, an international team, including University of Melbourne physicists, have created sensors capable of analysing chemical and biological samples with single-molecule sensitivity.
The negatively charged defects are called a nitrogen-vacancy (NV) centres. The negative charge comes from an electron trapped within the defect, the ‘spin’ of which is highly sensitive to any physical strain the diamond is placed under.
The researchers used microwaves to interrogate the electron’s spin as force was applied to the NV diamond, and found it made an exceptionally sensitive force sensor. They were even able to measure the biomechanical force exerted by single cells placed on NV diamond pillars.
In the same way, NV diamond nanostructures could be used to detect the mass of single molecules, or even the distribution of mass within a single large molecule such as a protein, the team predicts.
- Nano Letters 17, 1496−1503 (2017). doi: 10.1021/acs.nanolett.6b04544