A Switchable On-Off Gating Phenomenon in Dipalmitoylphosphatidylcholine Bilayers Controlled by Terahertz Waves

Tuning the permeability of cell membranes is crucial for many biological phenomena, such as osmotic balance, drug delivery, viral infection, etc. The dipalmitoylphosphatidylcholine (DPPC) bilayer as a key component of cell membranes is known to have poor water permeability because of the hydrophobic tail and high permeation barrier. In this work, through a series of molecular dynamics simulations, we find a surprising phenomenon for the first time that terahertz (THz) waves at specific field strengths or frequencies can result in a subtle structural change in DPPC molecules and a loose bilayer arrangement, which significantly reduces the potential of mean force (PMF) barriers for water. The underlying mechanism is the resonance between the DPPC bilayers and THz waves that leads to the rearrangement in bilayer structures. As a result, under the stimuli of THz waves the DPPC bilayer exhibits an excellent and controllable on-off gating behavior while maintaining its structural integrity. Consequently, the THz waves should be an effective and noninvasive strategy to adjust the permeability of biological membranes, opening a new window for novel biological applications.