ToF-SIMS 3D imaging unveils important insights on the cellular microenvironment during biomineralization of gold nanostructures

Sci Rep. 2020 Jan 14;10(1):261. doi: 10.1038/s41598-019-57136-w.

Abstract

The biomolecular imaging of cell-nanoparticle (NP) interactions using time-of-flight secondary ion mass spectrometry (ToF-SIMS) represents an evolving tool in nanotoxicology. In this study we present the three dimensional (3D) distribution of nanomaterials within biomolecular agglomerates using ToF-SIMS imaging. This novel approach was used to model the resistance of human alveolar A549 cells against gold (Au) ion toxicity through intra- and extracellular biomineralization. At low Au concentrations (≤1 mM HAuCl4) 3D-ToF-SIMS imaging reveals a homogenous intracellular distribution of Au-NPs in combination with polydisperse spherical NPs biomineralized in different layers on the cell surface. However, at higher precursor concentrations (≥2 mM) supplemented with biogenic spherical NPs as seeds, cells start to biosynthesize partially embedded long aspect ratio fiber-like Au nanostructures. Most interestingly, A549 cells seem to be able to sense the enhanced Au concentration. They change the chemical composition of the extracellular NP agglomerates from threonine-O-3-phosphate aureate to an arginine-Au(I)-imine. Furthermore they adopt the extracellular mineralization process from spheres to irregular structures to nanoribbons in a dose-dependent manner with increasing Au concentrations. The results achieved regarding size, shape and chemical specificity were cross checked by SEM-EDX and single particle (sp-)ICP-MS. Our findings demonstrate the potential of ToF-SIMS 3D imaging to better understand cell-NP interactions and their impact in nanotoxicology.

MeSH terms

  • A549 Cells
  • Cell Proliferation / drug effects
  • Cellular Microenvironment*
  • Gold / chemistry*
  • Gold Compounds / chemistry
  • Humans
  • Imaging, Three-Dimensional / methods*
  • Metal Nanoparticles / chemistry*
  • Metal Nanoparticles / toxicity
  • Microscopy, Electron, Scanning
  • Spectrometry, Mass, Secondary Ion

Substances

  • Gold Compounds
  • gold chloride
  • Gold