Imidazole-stabilized gold nanoparticles induce neuronal apoptosis: an in vitro and in vivo study

J Biomed Mater Res A. 2015 Apr;103(4):1436-46. doi: 10.1002/jbm.a.35289. Epub 2014 Aug 2.


Gold nanoparticles are increasingly being employed in innovative biological applications thanks to their advantages of material- and size-dependent physics and chemical interactions with the cellular systems. On the other hand, growing concern has emerged on the toxicity which would render gold-based nanoparticles harmful to cell cultures, animals, and humans. Emerging attention is focused on the interaction of gold nanoparticles with nervous system, especially regarding the ability to overcome the blood-brain barrier (BBB) which represents the major impediment to the delivery of therapeutics into the brain. We synthesized highly stable 2-mercapto-1-methylimidazole-stabilized gold-nanoparticles (AuNPs)-mmi to investigate their entry, accumulation, and toxicity in vitro (SH-SY5Y human neuroblastoma cells) and in vivo (brain of C57BL/6 mice) through optical and electron microscopy. After incubation in the cell culture medium at the lowest dose of 0.1 mg/mL the (AuNPs)-mmi nanoparticles were found compacted and recruited into endosome/lysosomes (1 h) before their fusion (2 h) and the onset of neuronal death by apoptosis (4 h) as proved by terminal-transferase-mediated dUTP nick end labeling assay and caspase-3 immunoreactivity. The ability of (AuNPs)-mmi to cross the BBB was assessed by injection in the caudal vein of C57BL/6 mice. Among different brain regions, the nanoparticles were found in the CaudatoPutamen area, mainly in the striatal neurons 4 h after injection. These neurons showed the typical hallmarks of apoptosis. Our findings provide, for the first time, the dynamic of 2-mercapto-1-methylimidazole nanogold uptake. The molecular mechanism which underlies the nanogold-driven apoptotic event is analyzed and discussed in order to take into account when designing nanomaterials to interface with biological structures.

Keywords: apoptosis; blood-brain barrier; cytotoxicity; neuroblastoma; thiolato ligands.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects*
  • Brain / drug effects
  • Brain / metabolism
  • Cell Shape / drug effects
  • Endocytosis / drug effects
  • Gold / pharmacology*
  • Humans
  • Imidazoles / pharmacology*
  • In Situ Nick-End Labeling
  • Injections, Intravenous
  • Metal Nanoparticles / chemistry*
  • Metal Nanoparticles / ultrastructure
  • Mice, Inbred C57BL
  • Neurons / cytology*
  • Time Factors
  • Tissue Distribution / drug effects


  • Imidazoles
  • Gold
  • imidazole