Exploring the Adsorption Process of Iodinated Contrast Medias onto Phospholipid Membranes: A Theoretical Toxicity Evaluation Study

Iodinated contrast media (ICM) molecules are widely used in medical diagnostic imaging. With the increasing consumption of ICM, these compounds have been identified in groundwater and surface water systems. However, the effect of these environmental pollutants on living organisms remains inadequately studied. Herein, we employed molecular dynamics (MD) simulations to investigate the interactions between ICM molecules and the cell membranes. Our findings indicated that the entry behavior of ICM molecules into the membrane is dependent on their chemical structure. The insertion of ICM molecules affects the alignment of phospholipid headgroups and the order parameters of phospholipid tails, resulting in membrane thickness fluctuations. In addition, we observed that the distribution of ICM molecules in the membrane was related to the type of phospholipid. The proportions of phospholipids around the ICM molecules were different. Furthermore, the potential of mean force revealed that different ICM molecules had distinct free energy change characteristics when they transport from an aqueous environment to the membrane center. Some ICM molecules could access the membrane center after overcoming a small energy barrier, suggesting their potential transmembrane ability. This work systematically studied the effects of ICM on cell membranes, providing theoretical evidence for the environmental hazards of ICM.