Dielectric Relaxation Analysis of Single-Stranded DNA in Liquid Crystals

Abstract

Since liquid crystals have found wide use in liquid crystal displays, we try to apply liquid crystals to biotechnology. The purpose of this study is to describe the physical properties of the biopolymer DNA in regard to electrooptics. Synthetic oligonucleotide molecules were dispersed in a nematic liquid crystal (NLC). The ICP analyses showed that all of the oligonuleotide molecules added dispersed in the NLC. This sample was injected into the twisted nematic liquid crystal display cells, and then we measured its dielectric properties. The NLC doped with oligonucleotide molecules exhibited dielectric relaxation characteristics, depending on the concentration of oligonucleotide molecules. After analyzing this effect by using the equivalent circuit model, we found a difference in electrical conductivity between Watson–Crick base pairs (AT and GC). This result suggests that the difference might have contributed to the existence of a functional group involved in the hydrogen-bond interaction.

Applications of Biomaterials to Liquid Crystals

“…During a series of measurements, some interesting results have emerged and these will be discussed in relation to their biological applications. First, we measured the dielectric properties of NLCs doped with ssDNA (A10b, C10b, G10b, and T10b) [ 53 ]. The result shows that 5CB doped with oligonucleotide exhibits dielectric relaxation from 10 1 to 10 2 Hz, as shown in Figure 5 .…”

“…( A ) shows the real part of the dielectric permittivity ε’ and ( B ) shows the imaginary part of the dielectric permittivity ε”. Adapted with permission from [ 53 ]. Copyright 2010 The Japan Society of Applied Physics.…”

Frequency Modulation Response of a Liquid Crystal Electrooptic Device Doped with Guanine Oligonucleotides

“…We found a difference in electrical conductivity between the Watson-Crick base pairs (AT and GC). 1) This difference might have originated from the existence of a functional group involved in a hydrogenbond interaction. 1) In the present study, we have determined the characteristics of the frequency modulation (FM) response in twist nematic liquid crystal displays (TN-LCDs) doped with G10b, where 5CB NLC was also used as the host medium.…”

“…1) This difference might have originated from the existence of a functional group involved in a hydrogenbond interaction. 1) In the present study, we have determined the characteristics of the frequency modulation (FM) response in twist nematic liquid crystal displays (TN-LCDs) doped with G10b, where 5CB NLC was also used as the host medium. We found that the frequency range of the FM effect extends from several tens of Hz to an upper limit of 100 Hz.…”

“…The method of sample preparation followed that in our previous report. 1) Then, TN-LCD cells were fabricated using 5CB NLC as the host LC medium and doped with G10b. The thickness of the LC layer was 6 m.…”