Interaction between Potassium Phosphate Bu er Solution and Modeling Cell Membrane Investigated by Sum Frequency Generation Vibrational Spectroscopy (cited: 1)

Potassium phosphate buffer solution has been widely used in the biological experiments, which represents an important process of the interaction between ions and biomolecules, yet the in fluences of potassium phosphate on biomolecules such as the cell membrane are still poorly understood at the molecular level. In this work, we have applied sum frequency generation vibrational spectroscopy and carried out a detailed study on the interaction between potassium phosphate buffer solution (PBS) and negative 1,2-dimyristoyl-d₅₄-sn-glycero-3-[phospho-rac-(1-glycerol)] (d₅₄-DMPG) lipid bilayer in real time. The PBS-induced dynamic change in the molecular structure of d₅₄-DMPG lipid bilayer was monitored using the spectral features of CD₂, CD₃, lipid head phosphate, and carbonyl groups for the first time. It is found that K⁺ can bind to the cell membrane and cause the signal change of CD₂, CD₃, lipid head phosphate, and carbonyl groups quickly. Potassium PBS interacts with lipid bilayers most likely by formation of toroidal pores inside the bilayer matrix. This result can provide a molecular basis for the interpretation of the effect of PBS on the ion-assisted transport of protein across the membrane.