Order-disorder phase transition of cell membrane induced by THz irradiation studied via fluorescence recovery after photobleaching

TL;DR

This study demonstrates that non-thermal THz radiation can induce an order-disorder phase transition in cell membrane lipids, affecting lipid dynamics without heating, with implications for safety standards and cell manipulation techniques.

Contribution

It provides experimental evidence that specific THz frequencies induce phase transitions in cell membranes through non-thermal mechanisms, advancing understanding of THz-biological interactions.

Findings

THz irradiation increases lipid diffusion constants at certain frequencies

Non-thermal effects confirmed by temperature calibration

Induces order-disorder phase transition in cell membrane lipids

Abstract

To elucidate the mechanism by which THz radiation non-thermally affects living organisms, the lateral diffusion constants of lipid molecules in the cell membranes of HeLa cells were measured using fluorescence recovery after photobleaching under THz wave irradiation (THz-FRAP) at frequencies of 0.10, 0.29, and 0.48 THz, with power densities ranging from 20 to 89 mW/cm2. The potential heating effects of the THz irradiation were eliminated through temperature calibration using an ultrathin thermocouple, allowing for the investigation of the non-thermal effects of THz radiation. Irradiation at 0.10 and 0.29 THz induced an increase in diffusion constants at temperatures lower than the cell growth temperature. This suggests that THz irradiation induces the order-disorder phase transition of the cell membrane lipids by affecting the dynamics of bound water molecules. Our findings have important implications for the establishment of safety standards for THz radiation and for the potential development of new methods for cell manipulation using THz irradiation in the future