Fullerene up-take alters bilayer structure and elasticity: A small angle X-ray study

Area of Science:

• Biophysics
• Materials Science
• Nanotechnology

Background:

• Phospholipid bilayers are fundamental to cell membrane structure and function.
• Fullerenes, like C60, are nanoparticles with unique properties.
• Understanding fullerene interactions with lipid bilayers is crucial for nanotoxicology and nanomedicine.

Purpose of the Study:

• To investigate the effects of fullerene (C60) on the structural and elastic properties of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) bilayers.
• To quantify changes in bilayer undulations, separation, and bending rigidity upon C60 incorporation.

Main Methods:

• Synchrotron small-angle X-ray scattering (SAXS) was employed to analyze multilamellar vesicles.
• Vesicles were prepared with varying concentrations of C60 (0, 2, and 10 mol.%).
• Experiments were conducted across a temperature range of 15-65 °C.

Main Results:

• C60 addition led to a significant increase in bilayer undulations (approximately 20%) and bilayer separation (approximately 15%).
• The linear expansion coefficient of the bilayers increased with C60 incorporation.
• A notable decrease in bilayer bending rigidity was observed, ranging from 20-40%.

Conclusions:

• Fullerene (C60) incorporation significantly modifies the structural and elastic properties of POPC lipid bilayers.
• Altered bilayer fluidity and elasticity changes induced by C60 suggest potential damaging effects on biomembranes.
• These findings have implications for the safety assessment of fullerene-based nanomaterials in biological systems.