The Imidazolium Ionic Liquids Toxicity Is Due to Their Effect on the Plasma Membrane

Ionic liquids (ILs) are organic salts with a low melting point, which is due to the fact that alkyl side chains chemically bonded to the ion hinder the crystallization of ILs. The low melting point of ILs has led to their widespread use as relatively harmless solvents. However, ILs have toxic properties, the mechanism of which is largely unknown, so identifying the cellular targets of ILs is of practical importance. In our work, we showed that imidazolium ILs are not able to penetrate model membranes without damaging them. We also found that inactivation of multidrug resistance (MDR) pumps in yeast cells does not increase their sensitivity to imidazolium ILs. The latter indicates that the target of the toxicity of imidazolium ILs is not in the cytoplasm. Thus, our data suggest that the disruption of the plasma membrane barrier function is the main cause of the toxicity of low concentrations of imidazolium ILs. We also showed that supplementation with imidazolium ILs restores the growth of cells with kinetically blocked glycolysis. Our data indicate that IL-induced minor disruption of the plasma membrane may, in some cases, be beneficial for the cells.