Bryce J Marquis

Publications (2)13.16 Total impact

• Article: The role of iron redox state in the genotoxicity of ultrafine superparamagnetic iron oxide nanoparticles.

  Neenu Singh, Gareth J S Jenkins, Bryant C Nelson, Bryce J Marquis, Thierry G G Maffeis, Andy P Brown, Paul M Williams, Chris J Wright, Shareen H Doak
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  ABSTRACT: Ultrafine superparamagnetic iron oxide nanoparticles (USPION) hold great potential for revolutionising biomedical applications such as MRI, localised hyperthermia, and targeted drug delivery. Though evidence is increasing regarding the influence of nanoparticle physico-chemical features on toxicity, data however, is lacking that assesses a range of such characteristics in parallel. We show that iron redox state, a subtle though important physico-chemical feature of USPION, dramatically modifies the cellular uptake of these nanoparticles and influences their induction of DNA damage. Surface chemistry was also found to have an impact and evidence to support a potential mechanism of oxidative DNA damage behind the observed responses has been demonstrated. As human exposure to ferrofluids is predicted to increase through nanomedicine based therapeutics, these findings are important in guiding the fabrication of USPION to ensure they have characteristics that support biocompatibility.
  Biomaterials 01/2012; 33(1):163-70. · 7.40 Impact Factor
• Article: NIST gold nanoparticle reference materials do not induce oxidative DNA damage.

  Bryant C Nelson, Elijah J Petersen, Bryce J Marquis, Donald H Atha, John T Elliott, Danielle Cleveland, Stephanie S Watson, I-Hsiang Tseng, Andrew Dillon, Mellisa Theodore, Joany Jackman
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  ABSTRACT: Abstract One primary challenge in nanotoxicology studies is the lack of well-characterised nanoparticle reference materials which could be used as positive or negative nanoparticle controls. The National Institute of Standards and Technology (NIST) has developed three gold nanoparticle (AuNP) reference materials (10, 30 and 60 nm). The genotoxicity of these nanoparticles was tested using HepG2 cells and calf-thymus DNA. DNA damage was assessed based on the specific and sensitive measurement of four oxidatively-modified DNA lesions (8-hydroxy-2´-deoxyguanosine, 8-hydroxy-2´-deoxyadenosine, (5´S)-8,5´-cyclo-2´-deoxyadenosine and (5´R)-8,5´-cyclo-2´-deoxyadenosine) using liquid chromatography/tandem mass spectrometry. Significantly elevated, dose-dependent DNA damage was not detected at concentrations up to 0.2 μg/ml, and free radicals were not detected using electron paramagnetic resonance spectroscopy. These data suggest that the NIST AuNPs could potentially serve as suitable negative-control nanoparticle reference materials for in vitro and in vivo genotoxicity studies. NIST AuNPs thus hold substantial promise for improving the reproducibility and reliability of nanoparticle genotoxicity studies.
  Nanotoxicology 11/2011; · 5.76 Impact Factor