Modulation of voltage-gated conductances of retinal horizontal cells by UV-excited TiO2 nanoparticles

Abstract

This study examines the ability of optically-excited titanium dioxide nanoparticles to influence voltage-gated ion channels in retinal horizontal cells. Voltage clamp recordings were obtained in the presence and absence of TiO₂ and ultraviolet laser excitation. Significant current changes were observed in response to UV light, particularly in the -40 mV to +40 mV region where voltage-gated Na⁺ and K⁺ channels have the highest conductance. Cells in proximity to UV-excited TiO₂ exhibited a left-shift in the current-voltage relation of around 10 mV in the activation of Na⁺ currents. These trends were not observed in control experiments where cells were excited with UV light without being exposed to TiO₂. Electrostatic force microscopy confirmed that electric fields can be induced in TiO₂ with UV light. Simulations using the Hodgkin-Huxley model yielded results which agreed with the experimental data and showed the I-V characteristics of individual ion channels in the presence of UV-excited TiO₂.

Keywords: Electrostatic force microscopy; Hodgkin–Huxley model; Retinal horizontal cell; TiO(2) nanoparticle; Voltage-gated ion channel.