Label-free, color-indicating, and sensitive biosensors of cholesteric liquid crystals on a single vertically aligned substrate

Abstract

Biosensors based on liquid crystal (LC) materials can be made by employing the sensitive interfacial effect between LC molecules and alignment layers on substrates. In the past, the optical texture observation method was used in the LC biosensor field. However, the method is limited by a complicated fabrication process and quantitative reproducibility of results that bv evidence that both the reliability and accuracy of LC biosensors need to be improved. In this report, we demonstrate that cholesteric LC (CLC) cells in which one substrate is coated with a vertically aligned layer can be used as a new sensing technology. The chirality of the single vertically anchored (SVA)/CLC biosensor was tested by detecting bovine serum albumin (BSA), a protein standard commonly used in the lab. The colors and corresponding spectrum of the SVA/CLC biosensor changed with the BSA concentrations. A detection limit of 1 ng/ml was observed for the SVA/CLC biosensor. The linear optical properties of the SVA/CLC biosensor produced cheap, inexpensive, and color-indicating detection of biomolecules, and may promote the technology of point-of-care devices for disease-related biomarker detection.

Label-Free Multi-Microfluidic Immunoassays with Liquid Crystals on Polydimethylsiloxane Biosensing Chips

“…Currently, these issues are the main obstacles to applying LC biosensors in practice. In addition, Chen et al invented the first single-substrate CLC biosensing device [25]. It seems that a better way to resolve time-consuming detection by LC biosensors can be found.…”

“…The vertical alignment layer of DMOAP forced the LCs to orient perpendicularly to the surface of the microfluidic channel, and the microfluidic channel without biomolecules appeared dark under crossed polarizers. However, the vertical anchoring force of the alignment layer (DMOAP) was diminished by the immobilized BSA[25], and the brightness of the microfluidic channel increased when observed under crossed polarizers, as shown inFigure 2. Moreover, the phenomenon under parallel polarizers was opposite of that under crossed polarizers.…”

Color-Indicating, Label-Free, Dye-Doped Liquid Crystal Organic-Polymer-Based-Bioinspired Sensor for Biomolecule Immunodetection

“…Cholesteric LC (CLC) is a special kind of LC material which has the property of Bragg reflection [ 13 , 14 , 15 , 16 ]. CLC-bioinspired sensors based on changing Bragg reflection have been proposed [ 17 , 18 ]. A sensitive color-indicating, label-free, easily used LC-bioinspired sensor has thus been demonstrated.…”

“…The most prominent of these techniques are plasmonic sensing and grating coupled interferometry (GCI) [ 19 , 20 , 21 , 22 , 23 ]. However, compared to GCI and plasmonic sensing, LC biosensors are cheaper and more portable, Furthermore, they can be measured with the naked eye [ 17 , 18 ].…”

Detection of heavy metal ions using whispering gallery mode lasing in functionalized liquid crystal microdroplets

“…Recently, liquid crystals (LCs) have been considered as promising sensing materials because the orientation and long-range arrangement of optically anisotropic LC molecules are sensitive to the chemical composition of their surrounding environment and, thus, molecular events at the LC interface can be converted into visible optical signals. A variety of LC-based detection strategies have been established for biochemical molecules such as DNAs [14,15], proteins [16][17][18][19], lipids [20,21] and artificial polymers [22,23].…”