Nanoscale free radical detection in living cells using diamond magnetometry
Dr. Romana Schirhagl (Groningen University Medical Center, Netherlands)

Free radicals play a key role in many biological processes including cell communication, immune responses, metabolism or cell development.
But they are also involved whenever something is wrong in a cell and are thus important in many diseases including cardiovascular diseases, cancer or bacterial and viral infection. Unfortunately, they are very reactive and short lived and thus difficult to detect for the state of the art. We have used diamond magnetometry to achieve this. We make use of nanodiamonds which we bring into cells. We then use of NV centers in diamonds to perform relaxometry measurements. These are sensitive to spin noise (in this case from radicals) and deliver signals that are equivalent to T1 in conventional MRI but from nanoscale voxels. Using this method, we are able to quantify free radical generation with nanoscale resolution in the nanomole range (1). In our recent work we were able to detect free radical generation in single mitochondria (the energy factories of the cell) in isolated form as well as in their cellular environment (2).

1 Perona Martínez, F., Nusantara, A.C., Chipaux, M., Padamati, S.K.
and Schirhagl, R., 2020. Nanodiamond Relaxometry-Based Detection of Free-Radical Species When Produced in Chemical Reactions in Biologically Relevant Conditions. ACS Sensors.
2 Nie, L., Nusantara, A.C., Damle, V.G., Sharmin, R., Evans, E.P.P., Hemelaar, S.R., van der Laan, K.J., Li, R., Martinez, F.P., Vedelaar, T. and Chipaux, M., Schirhagl, R., 2021. Quantum monitoring of cellular metabolic activities in single mitochondria. Science Advances, 7(21), p.eabf0573.