Fluorescent nanodiamonds are extensively investigated for biotechnology applications including drug delivery and biosensors. Here powerful quantum sensing techniques under ambient conditions with nanoscale resolution are transferred to life science. To develop efficient methods for obtaining nanodiamonds with color centers like the nitrogen-vacancy (NV) center is one of the topical issues of material science in view of combining nanoscale quantum sensing with bioapplications. Beside the creation of color centers by electron irradiation and thermal annealing in nanomaterial, the surface treatment of nanodiamonds is the major topic. Extensive surface cleaning and chemical modifications to stabilize the negatively charged NV-centers are required, followed by different surface functionalization with biomolecules for stable colloid solutions under cellular conditions and for instance directed transport of nanodiamonds in different biological systems or cell compartments.
Quantum sensing techniques based on nanodiamonds with color centers will become a pioneering imaging method for life science research and provide views of function and dynamics of molecular processes under physiological conditions that have not been previously possible.