Quantification of nanoparticle uptake by cells using an unbiased sampling method and electron microscopy.

Area of Science:

• Cell biology
• Nanotechnology
• Electron microscopy

Background:

• Accurate quantification of intracellular nanomaterials is crucial for understanding cellular responses.
• Existing methods may lack precision in determining nanoparticle accumulation within cells.

Purpose of the Study:

• To develop and validate a stereological method for accurately estimating nanoparticle numbers per cell.
• To assess cellular uptake of 50 nm gold nanoparticles using transmission electron microscopy.

Main Methods:

• Random sampling of cell pellets using a novel fractionator design.
• Stereological techniques combined with transmission electron microscopy for nanoparticle counting.
• Analysis of a known sample fraction to extrapolate total intracellular nanoparticle numbers.

Main Results:

• Accurate estimation of the mean number of 50 nm gold nanoparticles per cell.
• Precise determination of nanoparticle intracellular locations at the ultrastructural level.
• Demonstrated applicability using fibroblast cells exposed to gold nanoparticles.

Conclusions:

• The developed fractionator method is reliable for quantifying electron-dense nanomaterials in convex-shaped cells.
• This approach is adaptable for spatio-temporal and in vivo nanomaterial studies.
• Enables precise assessment of cellular nanoparticle uptake and distribution.