Polystyrene nanoparticle exposure induces ion-selective pores in lipid bilayers

Area of Science:

• Nanomaterial toxicology
• Biomembrane interactions
• Electrophysiology

Background:

• Engineered nanomaterials (ENM) can interact with biomembranes, potentially causing toxicity.
• Understanding these interactions is crucial for assessing ENM safety.

Purpose of the Study:

• To investigate pore formation in model lipid bilayers induced by polystyrene nanoparticles (PNP).
• To determine how nanoparticle and lipid charge influence the ion selectivity of induced pores.

Main Methods:

• Utilized electrophysiology to study 20nm PNP interacting with model bilayer lipid membranes (BLM).
• Varied PNP charge (positive/negative) and BLM lipid headgroup charge (cationic/zwitterionic/anionic).
• Analyzed current spikes and integral conductance to detect pore formation and ion selectivity.

Main Results:

• Both positively and negatively charged PNP induced pores in all tested BLM compositions.
• PNP-induced pores demonstrated ion selectivity, influenced by synergistic charge effects.
• Highest K+ selectivity occurred with negative PNP and lipids; highest Cl- selectivity with positive PNP and lipids.

Conclusions:

• Polystyrene nanoparticles can induce ion-selective pores in model biomembranes.
• The charge of both PNP functional groups and lipid headgroups dictates the degree of ion selectivity.
• This finding provides insights into nanomaterial-biomembrane interactions and potential toxicity mechanisms.