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

Abstract

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.

Nanodiamonds as Intracellular Probes for Imaging in Biology and Medicine

“…7). The observation has been confirmed by several groups (Yu et al 2005;Vial et al 2008;Fang et al 2011).…”

“…The biocompatibility of oxidized HPHT NDs was first examined in 2005 in human kidney cells by Chang's group (Yu et al 2005) and confirmed in subsequent studies by the same lab and others (Fu et al 2007;Vial et al 2008;Faklaris et al 2008;Lee et al 2013;Blaber et al 2013;Fang et al 2011;Liu et al 2009). Most studies assessed biocompatibility by MTT assay or by measuring levels of enzymatic activity.…”

“…NDs also do not alter long-term (10 days) cell growth ). Fang et al (2011) reported no significant alteration in growth or proliferation of a variety of cell types incubated with NDs for 8 days. The biocompatibility is not influenced by surface modification with peptides (Vial et al 2008), proteins or polymers .…”

Therapeutic applications of low-toxicity spherical nanocarbon materials

“…17,18,22,120,131 Several toxicological studies on nanodiamonds in vitro with various cell lines showed that they do not cause cytotoxic or detrimental effects on cellular proliferation. 132,133 Through comprehensive bioassays, it was confirmed that nanodiamonds do not induce inflammation or the production of tumor necrosis factor alpha or inducible nitric oxide synthase in cells after incubation. 117 Furthermore, by taking advantage of the intrinsic fluorescence of nanodiamonds, their biodistribution and biocompatibility were evaluated using a C. elegans and a mouse model.…”

Recent Developments and Applications of Nanodiamonds as Versatile Bioimaging Agents

“…[41][42][43] The combination of excellent chemical stability, photostability, and biocompatibility renders FNDs useful as a contrast agent for long-term cell imaging and tracking. [44][45][46] The application of FNDs at the cellular level has been previously discussed 14,15,18,19 and will not be repeated here. In this section, we will only address applications of these FNDs at the animal level.…”