Technological advancements in bio‐recognition using liquid crystals: Techniques, applications, and performance

Abstract

The application of liquid crystal (LC) materials has undergone a modern-day renaissance from its classical use in electronics industry as display devices to new-fangled techniques for optically detecting biological and chemical analytes. This review article deals with the emergence of LC materials as invaluable material for their use as labelfree sensing elements in the development of optical, electro-optical and electrochemical biosensors. The property of LC molecules to change their orientation on perturbation by any external stimuli or on interaction with bioanalytes or chemical species has been utilized by many researches for the fabrication of high sensitive LC-biosensors. In this review article we categorized LC-biosensor based on biomolecular reaction mechanism viz. enzymatic, nucleotides and immunoreaction in conjunction with operating principle at different LC interface namely LC-solid, LC-aqueous and LCdroplets. Based on bimolecular reaction mechanism, the application of LC has been delineated with recent progress made in designing of LC-interface for the detection of bio and chemical analytes of proteins, virus, bacteria, clinically relevant compounds, heavy metal ions and environmental pollutants. The review briefly describes the experimental set-ups, sensitivity, specificity, limit of detection and linear range of various viable and conspicuous LC-based biosensor platforms with associated advantages and disadvantages therein.

Cholesteric Liquid Crystals Sensors Based on Nanocellulose Derivatives for Improvement of Quality of Human Life: A Review

“…In these sensors, because they can be mounted between two glasses with a transparent conductive oxide on their surfaces, the transduction of the signal can be performed optically (through polarized optical microscopy) [67,84] or electrically (through, for example, measuring the capacity of the cell). [117] To produce these sensors, it is necessary that the glass surfaces are functionalized so that compounds can be fixed (such as proteins or aptamers), which will bind to the analytes, if any. [118] Copyright 2020, The authors, published by MDPI.…”

“…In these sensors, because they can be mounted between two glasses with a transparent conductive oxide on their surfaces, the transduction of the signal can be performed optically (through polarized optical microscopy) [ 67,84 ] or electrically (through, for example, measuring the capacity of the cell). [ 117 ]…”

Smart and intelligent optical materials for sensing applications

“…Gangwar et al [13] demonstrated the development of liquid crystals (LC) and used them as label‐free sensing compounds for fabricating different types of biosensors. The author classified LC biosensors based on biomolecular reaction mechanisms such as immunoreactions, enzymes, and nucleotides, along with operating principles at various LC interfaces such as LC droplet, LC solid, and LC aqueous surfaces.…”

Impact of carbon quantum dots on self-assembly and dielectric relaxation modes of a room temperature tri-component fluorinated antiferroelectric liquid crystal mixture

“…The tri-stable switching property in AFLCs is suitable for designing large flat-panel optoelectronic display devices. 9,10 In spite of ongoing research on AFLCs, some aspects such as the difficulty to obtain a high-quality dark state and having a low threshold are still major issues. This confines their applications in designing display devices based on AFLCs.…”