Dye- A nd dye-doped liquid crystals in biosensing

Liquid crystals (LCs) have been suggested to have a place in biological sensing for detection and quantitation of biomolecules. Through many years, texture observation has long been the core technique in LC-based bioassays. Its principle stems from the texture change of LCs due to the interruption of the initially homeotropic alignment in nematic bulks or the radial-to-bipolar configuration transition in LC droplets in the presence of biomolecules. Biodetection through optical texture observation is convenient but remains a qualitative method, and alternative approaches of detection and quantitative analysis are necessary for the development of a practical LC-based biosensor. In this study, we explore the potential of two dye-enhanced LCs, a dye LC (DLC) and a dye-doped LC (DDLC), in biosensing and protein quantitation. Depending on the chromophore or dye incorporated in DLC and DDLC, the dichroic features of these LCs enable us to analyze the change in their orientation in the presence of biomolecules by transmission spectrometry, from which spectral parameters are derived to establish novel LC-based protein quantitative methods.