Comparison of the photoluminescence properties of semiconductor quantum dots and non-blinking diamond nanoparticles and observation of the diffusion of diamond nanoparticles in cells

Abstract : Long-term observations of photoluminescence at the single-molecule level were until recently very difficult, due to the photobleachingof organic fluorophore molecules. Although inorganic semiconductor nanocrystals can overcome this difficulty showing very low photobleachingyield, they suffer from photoblinking. A new marker has been recently introduced, relying on diamond nanoparticles containingphotoluminescent color centers. In this work we compare the photoluminescence of single quantum dots (QDs) to the one of nanodiamondscontaining a single-color center. Contrary to other markers, photoluminescent nanodiamonds present a perfect photostability andno photoblinking. At saturation of their excitation, nanodiamonds photoluminescence intensity with a single NV-color center is only threetimes smaller than one of the single QDs. Moreover, the bright and stable photoluminescence of nanodiamonds allows wide field observationsof single nanoparticles motion. We demonstrate the possibility of recording the trajectory of such single particle in culture cells.