Bright Fluorescent Nanodiamonds:  No Photobleaching and Low Cytotoxicity

Abstract

Diamond nanocrystals emit bright fluorescence at 600-800 nm after irradiation by a 3 MeV proton beam (5 x 1015 ions/cm2) and annealing at 800 degrees C (2 h) in vacuum. The irradiation/annealing process yields high concentrations of nitrogen-vacancy defect centers ( approximately 107 centers/mum3), making possible visualization of the individual 100 nm diamond crystallites using a fluorescence microscope. The fluorescent nanodiamonds (FND) show no sign of photobleaching and can be taken up by mammalian cells with minimal cytotoxicity. The nanomaterial can have far-reaching biological applications.

Inhibition of type 1 fimbriae-mediated Escherichia coli adhesion and biofilm formation by trimeric cluster thiomannosides conjugated to diamond nanoparticles

“…[43][44][45][46][47][48][49][50] Although their in vivo toxicity depends in particular on their surface characteristics (as well as the nature of the ligands they carry on their surface), 51 ND particles have thus far been reported not to induce significant cytotoxicity in a variety of cell types. [51][52][53][54] The demonstration that our 1 st -generation sugar-conjugated NDs do show marked anti-adhesive activity in cell-based assays without displaying toxicity against eukaryotic cells conforted us in our choice of particle and convinced us that sugar-NDs should indeed be further pursued as biomaterials. Particularly striking was the unexpected observation that these ND-mannose conjugates are able to inhibit E. coliinduced biofilm formation.…”

“…Their synthesis has been carried out by implementing a modular strategy that takes advantage of the radical addition of thiols to double bonds (ene-thiol "click" coupling) for the construction of glycodendrons. 54 The ene-thiol addition proceeds with anti-Markovnikov regioselectivity and allows the incorporation of thiosaccharidic motifs onto a polyene branching element. The resulting multivalent sugar cluster can be further armed with an azido group for subsequent conjugation purposes via Cu(I)-catalyzed azide-alkyne (CuAAC) coupling reaction with suitable polyakyne partners.…”

Study on fluorescence properties of carbogenic nanoparticles and their application for the determination of ferrous succinate

“…The particles were called ''carbogenic'' because they were not of pure carbon composition like carbon nanotubes or carbon nanodiamond but proved to be oxygen-containing carbon dots. Fluorescent carbogenic NPs can be obtained by various methods such as laser ablation of graphite [4,5] or carbon powders [6], proton-beam irradiation of nanodiamonds [7,8], carboxylation of carbon nanotubes [9][10][11], electrooxidation of graphite [12], hydrothermal decomposition of ammonium citrate salts [13,14] or separating from candle soot [15].…”

Luminescent nanodiamonds for biomedical applications

“…Optical measurements based on luminescence Chao et al 2007;Chang et al 2008a, b;Faklaris et al 2008Faklaris et al , 2009bLiu et al 2009;Yuan et al 2009;Zhang et al 2009a) or Raman signatures ) have shown that nanodiamonds are internalised and tend to be located in endocytic vesicles, but they do not enter the nucleus. This has been confirmed by transmission electron microscopy and atomic force microscopy (Chang et al 2008a, b;Faklaris et al 2008Faklaris et al , 2009bYu et al 2005;Liu et al 2009;Zhang et al 2009a).…”