Effect of acetylsalicylic acid on the current-voltage characteristics of planar lipid membranes

Monitoring of influence of acetylsalicylic acid (ASA) on lipid bilayer conductance may contribute to better understanding of molecular mechanisms underlying passage of ASA into cells. This paper presents effects of increasing sweeping potential on stability of egg yolk phosphatidylcholine planar bilayer lipid membranes (BLM) without or with cholesterol incubated in the presence of ASA. We demonstrated that current flow through bilayer membranes generated fluctuating pores in their structure. Presence of cholesterol in the membrane caused an increase in the value of the breakdown potential, thus confirming that cholesterol had a stabilizing effect on BLM. Otherwise, ASA significantly reduced these values regardless of cholesterol concentration. Overall, by destabilizing the lipid bilayer, ASA contributed to the formation of metastable single pores, which facilitated ASA diffusion through a bilayer. Our data point out that ASA transport across the lipid bilayer takes place predominantly via the process of passive diffusion. In conclusion, the effects of ASA on lipid bilayer stability may contribute to drug transport through membrane lipid bilayers.