Photoluminescent diamond nanoparticles for cell labeling: study of the uptake mechanism in mammalian cells.
Diamond nanoparticles (nanodiamonds) have been recently proposed as new labels for cellular imaging. For small nanodiamonds (size <40 nm), resonant laser scattering and Raman scattering cross sections are too small to allow single nanoparticle observation. Nanodiamonds can, however, be rendered photoluminescent with a perfect photostability at room temperature. Such a remarkable property allows easier single-particle tracking over long time scales. In this work, we use photoluminescent nanodiamonds of size <50 nm for intracellular labeling and investigate the mechanism of their uptake by living cells. By blocking selectively different uptake processes, we show that nanodiamonds enter cells mainly by endocytosis, and converging data indicate that it is clathrin-mediated. We also examine nanodiamond intracellular localization in endocytic vesicles using immunofluorescence and transmission electron microscopy. We find a high degree of colocalization between vesicles and the biggest nanoparticles or aggregates, while the smallest particles appear free in the cytosol. Our results pave the way for the use of photoluminescent nanodiamonds in targeted intracellular labeling or biomolecule delivery.
Laboratoire de Photonique Quantique et Moleculaire, Ecole Normale Superieure de Cachan and CNRS UMR 8537, Cachan, France.
Orestis
O
Faklaris
Vandana
V
Joshi
Theano
T
Irinopoulou
Patrick
P
Tauc
Mohamed
M
Sennour
Hugues
H
Girard
Céline
C
Gesset
Jean-Charles
JC
Arnault
Alain
A
Thorel
Jean-Paul
JP
Boudou
Patrick A
PA
Curmi
François
F
Treussart
D003460:Crystallization / Q000379:methods*; D018130:Diamond / Q000737:chemistry / Q000493:pharmacokinetics*; D006367:HeLa Cells; D006801:Humans; D008163:Luminescent Measurements / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D013194:Staining and Labeling / Q000379:methods; D013499:Surface Properties
D046911:Macromolecular Substances; D018130:Diamond