  Nanodiamonds (NDs) containing silicon vacancy (SiV) defects were evaluated as
a potential biomarker for the labeling and fluorescent imaging of neural
precursor cells (NPCs). SiV-containing NDs were synthesized using chemical
vapor deposition and silicon ion implantation. Spectrally, SiV-containing NDs
exhibited extremely stable fluorescence and narrow bandwidth emission with an
excellent signal to noise ratio exceeding that of NDs containing
nitrogen-vacancy (NV) centers. NPCs labeled with NDs exhibited normal cell
viability and proliferative properties consistent with biocompatibility. We
conclude that SiVcontaining NDs are a promising biomedical research tool for
cellular labeling and optical imaging in stem cell research.
