The Exocytosis of Fluorescent Nanodiamond and Its Use as a Long-Term Cell Tracker

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2011-12, Vol.7 (23), p.3363-3370
• Main Authors: Fang, Chia-Yi, Vaijayanthimala, V., Cheng, Chi-An, Yeh, Shih-Hua, Chang, Ching-Fang, Li, Chung-Leung, Chang, Huan-Cheng
• Format: Article
• Language: English
• Subjects: 3T3-L1 Cells; Animals; Biocompatibility; biomaterials; Cancer; Cell Cycle; Cell Tracking - methods; cells; diamond nanoparticles; Esters; Exocytosis; Flow Cytometry; Fluoresceins - metabolism; Fluorescence; HeLa Cells; Humans; imaging; Light; Marking; Mice; Microscopy, Fluorescence; Nanodiamonds - chemistry; Nanostructure; Nanotechnology; Scattering, Radiation; Staining and Labeling; Stem cells; Succinimides - metabolism; Tracking
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201101233

Fluorescent nanodiamond (FND) has excellent biocompatibility and photostability, making it well suited for long‐term labeling and tracking of cancer and stem cells. To prove the concept, the exocytosis of FND particles (size ≈100 nm) from three cell lines—HeLa cervical cancer cells, 3T3‐L1 pre‐adipocytes, and 489‐2.1 multipotent stromal cells—is studied in detail. FND labeling is performed by incubating the cells in a serum‐free medium containing 80 μg mL−1 FND for 4 h. No significant alteration in growth or proliferation of the FND‐labeled cells, including the multipotent stromal cells, is observed for up to 8 days. Flow cytometric analysis, in combination with parallel cell doubling‐time measurements, indicates that there is little (≈15% or less) excretion of the endocytosed FND particles after 6 days of labeling for both HeLa and 489‐2.1 cells, but exocytosis occurs more readily (up to 30%) for 3T3‐L1 preadipocytes. A comparative experiment with FND and the widely used dye, carboxyfluorescein diacetate succinimidyl ester, demonstrates that the nanoparticle platform is a promising alternate probe for long‐term cell labeling and tracking applications. Fluorescent nanodiamond (FND) emits far‐red photoluminescence from built‐in nitrogen‐vacancy centers. The particles of 100 nm in size are readily taken up by cells with low exocytosis. This characteristic, together with the high biocompatibility and excellent photostability of this nanomaterial, makes FND a promising candidate for long‐term labeling and tracking of cancer and stem cells.