Twisted-nematic-mode liquid crystal display with a DNA alignment layer

In this study, we investigated the use of biomaterials in optoelectronic applications. One of the most abundant biomaterials in nature is deoxyribonucleic acid (DNA). It was used in this study as an alignment layer to fabricate a twisted-nematic-mode (TN-mode) liquid crystal display (LCD). To create the LCD, a cheap DNA material extracted from salmon was used to coat an indium tin oxide glass substrate, and the DNA chains were aligned with a simple but effective mechanical shearing method at room temperature. Then small rod-type LC molecules were spread on top of the alignment layer, obliquely aligned with respect to the long axis of the DNA chains because of the polar and topographical interactions between the LC molecules and the DNA material. The electro-optical characteristics of the LCD device were examined to compare the properties of the DNA-based LCD with those of a TN-mode LCD fabricated with the conventional rubbed polymer alignment layer. We believe our method provides an easy and useful tool for the fabrication of biomaterial-based optoelectronic devices.