As biomolecules vibrate and rotate in the terahertz band, the biological effects of terahertz electromagnetic fields have drawn considerable attention from the physiological and medical communities. Ion channels are the basis of biological electrical signals, so studying the effect of terahertz electromagnetic fields on ion channels is significant. In this paper, the effect of a terahertz electromagnetic field with three different frequencies, 6, 15, and 25 THz, on the Kv1.2 potassium ion channel was investigated by molecular dynamics simulations. The results show that an electromagnetic field with a 15 THz frequency can significantly enhance the permeability of the Kv1.2 potassium ion channel, which is 1.7 times higher than without an applied electric field. By analyzing the behavior of water molecules, it is found that the electromagnetic field with the 15 THz frequency shortens the duration of frozen and relaxation processes when potassium ions pass through the channel, increases the proportion of the direct knock-on mode, and, thus, enhances the permeability of the Kv1.2 potassium ion channel.

Potassium (K) channels show the highest variability and most frequent alterations in expression in many tumor types, and modulation of K⁺ channels may represent a new window for cancer therapy. In previous work, we found that a terahertz (THz) field incident along the z-axis with a frequency of 51.87 THz increased the ion flux through K⁺ channels. In practice, it is difficult to ensure that the incident electromagnetic (EM) wave is strictly parallel to the direction of channel ion flow. In this paper, we found by changing the direction of the applied electric field that the EM wave of a specific frequency has the largest ion flux when the incident direction is along the ion flow, and the smallest ion flux when the incident direction is perpendicular to the ion flow, and that overall the EM wave of this frequency enhances the ion flow of the K⁺ channel. Changes in the direction of the applied field at a specific frequency affect the stability of the φ dihedral angle of the GLY77 residue and alter the ion permeation mechanism in the selectivity filter (SF) region, thus affecting the ion flux. Therefore, this frequency can be used to modulate K⁺ fluxes by THz waves to cause rapid apoptosis in potassium-overloaded tumor cells. This approach consequently represents an important tool for the treatment of cancer and is expected to be applied in practical therapy.

Ion transport molecules are involved in many physiological and pathological processes and are considered potential targets for cancer treatment. In the large family of ion transport molecules, potassium (K) ion channels, as surface-expressed proteins, show the highest variability and most frequent expression changes in many tumor types. The key to exploring the permeation of K⁺ through potassium channels lies in the conserved sequence TVGYG, which is common in the selectivity filter (SF) region of all potassium channels. We found that the K⁺ flux significantly increased with the help of a specific frequency terahertz electromagnetic wave (51.87 THz) in the KcsA channel using a molecular dynamics combined model through the combined simulation of the constant electric field method and ion imbalance method. This frequency has the strongest absorption peak in the infrared spectrum of -C=O groups in the SF region. With the applied electric field of 51.87 THz, the Y78 residue at the S₁ site of the SF has a smaller vibration amplitude and a more stable structure, which enables the K⁺ to bind closely with the carbonyl oxygen atoms in the SF and realize ion conduction in a more efficient direct Coulomb knock-on.

In this paper, the influence of external terahertz electromagnetic fields with different frequencies of 4 THz, 10 THz, 15 THz, and 20 THz on the permeability of the Kv1.2 voltage-gated potassium ion channel on the nerve cell membrane was studied using the combined model of the “Constant Electric Field-Ion Imbalance” method by molecular dynamics. We found that although the applied terahertz electric field does not produce strong resonance with the –C=O groups of the conservative sequence T-V-G-Y-G amino acid residue of the selective filter (SF) of the channel, it would affect the stability of the electrostatic bond between potassium ions and the carbonyl group of T-V-G-Y-G of SF, and it would affect the stability of the hydrogen bond between water molecules and oxygen atoms of the hydroxyl group of the 374THR side chain at the SF entrance, changing the potential and occupied states of ions in the SF and the occurrence probability of the permeation mode of ions and resulting in the change in the permeability of the channel. Compared with no external electric field, when the external electric field with 15 THz frequency is applied, the lifetime of the hydrogen bond is reduced by 29%, the probability of the “soft knock on” mode is decreased by 46.9%, and the ion flux of the channel is activated by 67.7%. Our research results support the view that compared to “direct knock-on”, “soft knock-on” is a slower permeation mode.

A new package structure with three convex phosphor layers is shown to enhance the angular color uniformity based on modeling and experimental verification. The color uniformity has been improved by tailoring the phosphor concentration distribution of the three layers. The experimental measurements indicate that the deviation of angular correlated color temperature (CCT) can be reduced from 152.9, 487.2, and 586.4 K to 51.3, 55.1, and 78.7 K compared with the conventional structure at the average CCT of 4500, 5500, and 6200 K, respectively. Luminous flux and optical output power of LED packages with optimized multilayer phosphor have been measured and are reduced no more than 5% compared with the single phosphor layer packages.

Potassium channels are essential for various physiological functions, with their high selectivity being a critical foundation. The blockage of sodium ions in potassium channels is a crucial aspect of their selectivity, yet the underlying mechanism remains unclear. In this study, we investigated the mechanisms underlying the sodium ion blockage through molecular dynamics simulations. We found that when sodium ions bind to the B_{34} site, the water molecule at the entrance of the selectivity filter forms a strong association with the ion, preventing effective knock-on movement and resulting in a 93% loss of permeability. Given the vibrational frequencies of biomolecules within the terahertz range, terahertz waves are considered effective tools for biomolecular modulation. Consequently, we explored the influence of terahertz waves on the blockage of sodium ions. Our results show that a 15 THz electric field significantly disrupts the stable binding of the water molecule to the sodium ion at the B_{34} site, enhancing interactions between the ion in the cavity and those in the selectivity filter, thereby alleviating the blockage. This study reveals that the dynamic state of water molecules in biological systems is closely related to biomolecular functions and is influenced by external physical fields, such as terahertz electric fields. These findings provide new insights into potassium channels' selectivity mechanisms and broaden terahertz fields' potential applications in regulating channel functions.