Quantum Sensing of Magnetic Nanoparticles for in-vitro Cell Imaging in Living Tissue

Understanding the processes underlying cancer dissemination is a critical focus in contemporary medical research, primarily due to the current limitations in observing single-cell behavior in biological tissue in vivo. Widefield imaging with ensembles of nitrogen-vacancy (NV) centers in diamond offers a promising technique for visualizing individual cells by mapping the spatial distribution of superparamagnetic iron oxide nanoparticles (SPIONs) used as magnetic markers [1,2]. By interrogating the transition energies of an ensemble of spin systems with an optically detected magnetic resonance scheme, we can characterize the magnetic environment around the ensemble [3]. This approach allows us to determine the positions of magnetic markers within the microscope's field of view at a sub-cellular scale. By either labeling the cell surface or incorporating the markers into cells, different cell types can be precisely localized without interfering with the biological processes involved in the cells behavior. The non-invasive nature of this magnetic imaging technique facilitates long-term studies and is limited only by the biological sample's viability, offering a novel approach to therapeutic interventions and providing new insights into medical research.

[1] Glenn, D. R. et al. Single-cell magnetic imaging using a quantum diamond microscope. Nature Methods 12, 736-738. (2015)

[2] Le Sage, D. et al. Optical magnetic imaging of living cells. Nature 496, 486-489. (2013)

[3] Hollendonner, M. et al. Quantum sensing of electric field distributions of liquid electrolytes with NV-centers in nanodiamonds. New Journal of Physics 25 (2023).

*German Research Foundation: FOR NA 1764/2-1; Federal Ministry of Education and Research: QUBIS 13N16749