title: Preferential tumour accumulation of gold nanoparticles, visualised by Magnetic Resonance Imaging: radiosensitisation studies in vivo and in vitro.
abstract: OBJECTIVE
  To investigate the radiosensitisation of gold nanoparticles (GNP) with an average diameter of 5 nm coated with the gadolinium chelating agent dithiolated diethylenetriaminepentaacetic gadolinium (Au@DTDTPA:Gd) in vitro and in mice bearing tumours (MC7-L1).
  
  
  METHODS
  In vivo, the gadolinium chelate coating allows one to perform real-time Magnetic Resonance Imaging (MRI) pharmacokinetic analysis during intravenous infusion. Experiments were performed following treatment with 10 Gy of 150 kVp X-rays. In vitro experiments were also performed with clonogenic assays to generate dose response curves for the same cells.
  
  
  RESULTS
  We observed a preferential accumulation of Au@DTDTPA:Gd in tumours; a substantial toxicity for tumour cells in vitro, but no obvious toxicity for mice; and the absence of a synergistic effect with Au@DTDTPA:Gd and radiation in all experiments.
  
  
  CONCLUSIONS
  The additional absorption of radiation and the subsequent increase in secondary electrons, attributable to the presence of gold in Au@DTDTPA:Gd, does not lead to radiosensitisation. However, this chelating agent exhibits a chemotherapeutic action which warrants further investigation. When compared to positive results obtained by others on radiosensitisation by GNP, the present study suggests that the chemotherapeutic and radiosensitising properties of GNP may depend strongly on the nature of the coating.
authors.affiliation: Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Quebec, Canada.
authors.forename: Etienne M
authors.initials: EM
authors.lastname: Hébert
authors.forename: Pierre-Jean
authors.initials: PJ
authors.lastname: Debouttière
authors.forename: Martin
authors.initials: M
authors.lastname: Lepage
authors.forename: Léon
authors.initials: L
authors.lastname: Sanche
authors.forename: Darel J
authors.initials: DJ
authors.lastname: Hunting
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D005260:Female; D019786:Gadolinium DTPA / Q000493:pharmacokinetics* / Q000494:pharmacology; D006046:Gold / Q000493:pharmacokinetics* / Q000494:pharmacology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008325:Mammary Neoplasms, Experimental / Q000378:metabolism / Q000401:mortality / Q000532:radiotherapy*; D051379:Mice; D008807:Mice, Inbred BALB C; D053758:Nanoparticles; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*
chemical_list: D011838:Radiation-Sensitizing Agents; D006046:Gold; D019786:Gadolinium DTPA