# Modulation of confined water dynamics in ion channels by terahertz electric fields

## TL;DR

This paper explores how terahertz electric fields affect water dynamics in biological ion channels, offering insights into how these fields can modulate channel function.

## Contribution

The study reveals frequency-selective modulation of confined water dynamics by terahertz fields, linking it to water–protein interactions and channel function.

## Key findings

- Terahertz fields at 16 THz enhance water mobility in ion channels, while 24 THz suppress it.
- Water mobility and orientational polarization in ion channels are strongly influenced by spatial confinement and water–protein interactions.
- Field strength and direction determine how terahertz fields regulate confined water dynamics.

## Abstract

Water confined within nanoscale environments exhibits dynamic behaviors distinct from bulk water, with profound implications for nanodevice function. Biological ion channels, as natural nanopores, represent ideal systems for investigating such confined dynamics. The dynamical properties of water molecules in the pore regions of voltage-gated potassium and sodium channels were systematically compared, and their responses to terahertz electric fields were examined using molecular dynamics simulations. Spatial confinement and water–protein interactions markedly reduce water mobility and induce strong orientational polarization. Terahertz electric fields produce frequency-selective effects: application of a 16 THz field perpendicular to the membrane enhances water mobility, whereas a 24 THz field suppresses it, indicating selective excitation of water vibrational modes that may modulate channel function. The regulation of confined water is further shown to depend on both field strength and incident direction. These findings elucidate how terahertz fields modulate hydration dynamics, provide mechanistic insight into electric field–protein interactions, and offer guidance for the rational design of biomimetic nanofluidic systems and field-responsive biointerfaces.

Water confined in biological channels shows distinct dynamics. Terahertz fields selectively modulate this behavior, providing insight into field–protein coupling and guiding biomimetic design.