Characterization of Dielectric Responses of Human Cancer Cells in the Terahertz Region

Abstract

Terahertz time-domain attenuated total reflection spectroscopy, in combination with a two-interface model, is used to determine the complex dielectric constants of cultured human cancer cells (DLD-1, HEK293 and HeLa). Picosecond and sub-picosecond water dynamics are dominant in the measured complex dielectric constants of these cells. We demonstrate that dielectric responses below 1.0 THz best characterize the particular water dynamics of cancer cells when compared with extracellular water. Debye-Lorentz fitting revealed that this is due to a significantly attenuated slow relaxation mode and enhanced fast relaxation mode of the water in these cancer cells. These findings could lead to a new procedure to digitally evaluate cellular activities or functions, in terms of intracellular water dynamics, and remove the veil from the mysterious intracellular milieu.

Biomedical Applications of Terahertz Spectroscopy and Imaging

“…(D) Differences in the complex dielectric constants between distilled water and cultured human cancer cells, including DLD-1[ 9 _ T D $ D I F F ] (red), HEK293 (black), and HeLa (green) (e_water-e_cell) [31]. (E) Absorption coefficients of paraffin-embedded brain gliomas (red) and normal tissues (black).…”

“…Moreover, various cultured human cancer cells can be distinguished by their different complex dielectric constants ( Figure 2D) [31]. Notably, the THz system has demonstrated greater sensitivity in measuring tiny structural changes in cultured cell monolayers than conventional optical phasecontrast microscopy and electric cell-substrate impedance sensing [32].…”

Analysis of dermal composite conditions using collagen absorption characteristics in the THz range

“…The absorption magnitudes of the protein depend on the kind, content, and hydration state of the proteins. The absorption spectrum of a cell is similar to that of water, even though there is a difference owing to hydration [20]. We considered that the collagen caused the large absorption in the dermis, because more than 70% of the dry weight of a normal dermis consists of collagen, and collagen has hydrophobic bonding; there is little suppression of molecular vibration by hydration.…”

Compact All-Quantum-Dot-Based Tunable THz Laser Source

“…Such laser source emitting tunable THz radiation is of great interest for a number of applications, including indoor communications [27,28], biomedical imaging [29,30], spectroscopy [31,32], homeland security and defense [33,34], among others.…”