Real-Time Background-Free Selective Imaging of Fluorescent Nanodiamonds in Vivo

• Published in: Nano letters Vol. 12; no. 11; pp. 5726 - 5732
• Main Authors: Igarashi, Ryuji, Yoshinari, Yohsuke, Yokota, Hiroaki, Sugi, Takuma, Sugihara, Fuminori, Ikeda, Kazuhiro, Sumiya, Hitoshi, Tsuji, Shigenori, Mori, Ikue, Tochio, Hidehito, Harada, Yoshie, Shirakawa, Masahiro
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 14.11.2012
• Subjects: Animals; Biocompatibility; Biomedical materials; Caenorhabditis elegans; Cross-disciplinary physics: materials science; rheology; Electron spin; Exact sciences and technology; Fluorescence; HeLa Cells; Humans; Imaging; In vivo testing; In vivo tests; Magnetic Resonance Spectroscopy - methods; Materials science; Mice; Microscopy, Fluorescence - methods; Nanocrystalline materials; Nanodiamonds - chemistry; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Nanotechnology - methods; Nitrogen - chemistry; Photons; Physics; Sensitivity and Specificity; Spectrometry, Fluorescence - methods; Surgical implants; Nitrogen-vacancy center; HeLa cells; in vivo imaging; C. elegans; optically detected magnetic resonance; mice; Vacancies; Tracking; Ground states; Synthetic diamond; Fluorescence; Real time; Polycrystalline diamond; In vivo; Lifetime; Fluorescent material; Imaging; Electron paramagnetic resonance; Spin state; Nanostructured materials; Fluorescence microscopy; Photobleaching
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl302979d

Recent developments of imaging techniques have enabled fluorescence microscopy to investigate the localization and dynamics of intracellular substances of interest even at the single-molecule level. However, such sensitive detection is often hampered by autofluorescence arising from endogenous molecules. Those unwanted signals are generally reduced by utilizing differences in either wavelength or fluorescence lifetime; nevertheless, extraction of the signal of interest is often insufficient, particularly for in vivo imaging. Here, we describe a potential method for the selective imaging of nitrogen-vacancy centers (NVCs) in nanodiamonds. This method is based on the property of NVCs that the fluorescence intensity sensitively depends on the ground state spin configuration which can be regulated by electron spin magnetic resonance. Because the NVC fluorescence exhibits neither photobleaching nor photoblinking, this protocol allowed us to conduct long-term tracking of a single nanodiamond in both Caenorhabditis elegans and mice, with excellent imaging contrast even in the presence of strong background autofluorescence.