Sensing of silver nanoparticles on/in endothelial cells using atomic force spectroscopy

Area of Science:

• Biophysics
• Cell Biology
• Nanotoxicology

Background:

• Endothelial cells form a critical barrier, interacting with blood-borne substances like nanoparticles.
• Atomic force spectroscopy (AFM) offers a sensitive method to probe cell mechanics.

Purpose of the Study:

• To investigate if silver nanoparticle (SNP) exposure alters endothelial cell (EA.hy926) mechanical properties.
• To determine if AFM-based mechanical response can serve as a bio-indicator for cellular physiological state after SNP exposure.

Main Methods:

• Characterization of SNPs using transmission electron microscopy and dynamic light scattering.
• Assessment of cell viability using the tetrazolium salt reduction test.
• Atomic force spectroscopy (AFM) to measure cell elasticity with different probe geometries (ball and cone).
• Morphological analysis via AFM and intracellular SNP detection via transmission electron microscopy.

Main Results:

• Cells exposed to higher concentrations of silver nanoparticles (3.6 and 16 μg/mL) exhibited reduced elasticity.
• This decrease in elasticity was observed in both native and formaldehyde-fixed cells.
• Silver nanoparticle agglomerates were found on cell membranes and within the cells.
• AFM detected changes in cell elasticity regardless of probe geometry.

Conclusions:

• Silver nanoparticle exposure can lead to decreased endothelial cell elasticity, potentially due to cytoskeleton reorganization.
• AFM-based mechanical measurements show promise as a bio-indicator for assessing cellular responses to nanoparticle exposure.
• The observed mechanical changes are independent of cell fixation methods.