A liquid-crystal-based DNA biosensor for pathogen detection

Abstract

A liquid-crystal (LC)-filled transmission electron microscopy (TEM) grid cell coated with the cationic surfactant dodecyltrimethylammonium bromide (DTAB), to which a single-stranded deoxyribonucleic acid probe (ssDNAprobe) was adsorbed at the LC/aqueous interface (TEMDTAB/DNA), was applied for the highly specific detection of target DNA molecules. The DTAB-coated E7 (used LC mixture) in the TEM grid (TEMDTAB) exhibited a homeotropic orientation, and changed to a planar orientation upon adsorption of the ssDNAprobe. The TEMDTAB/DNA was then exposed to complementary (target) ssDNA, which resulted in a planar-to-homeotropic configurational change of E7 that could be observed through a polarized optical microscope under crossed polarizers. The optimum adsorption density (2 μM) of ssDNAprobe enabled the detection of ≥0.05 nM complementary ssDNA. This TEMDTAB/DNA biosensor could differentiate complementary ssDNA from mismatched ssDNA as well as double-stranded DNA. It also successfully detected the genomic DNAs of the bacterium Erwinia carotovora and the fungi Rhazictonia solani. Owe to the high specificity, sensitivity, and label-free detection, this biosensor may broaden the applications of LC-based biosensors to pathogen detection.

Seeing the Unseen: The Role of Liquid Crystals in Gas‐Sensing Technologies

“…[ 15–21 ] Regarding biosensors, the concept involves either the imaging of targeted species displayed at solid surfaces, or sensing at LC/aqueous interfaces (LC thin films or droplets). So far, LC‐based biosensors have been reported to detect a wide range of biomolecules such as glucose, [ 22 ] cholesterol, [ 23 ] lipids, [ 24 ] antimicrobial peptides, [ 25 ] proteins, [ 26,27 ] antigens, [ 28 ] pathogen DNA, [ 29 ] viruses, [ 30 ] bacteria, [ 31 ] or mammalian cells. [ 32,33 ] Nonetheless, the exploitation of LCs in biosensing devices has already been reviewed by other authors [ 16,19 ] and is outside the scope of this work.…”

Application and Technique of Liquid Crystal-Based Biosensors

“…The Park group [48] exploited the LC-based DNA biosensor. In this experiment, an LC-filled TEM grid cell was coated with the cationic surfactant dodecyltrimethylammonium bromide (DTAB).…”

Quantitative and rapid Plasmodium falciparum malaria diagnosis and artemisinin-resistance detection using a CMOS Lab-on-Chip platform

“…Each LAMP reaction contained the following: 1.5 µL of 10 × isothermal buffer (New England Biolabs) 3 for qPCR experiments, and enough nuclease-free water (ThermoFisher Scientific) to bring the volume to 30 µL. Experiments were conducted twice and each condition was ran in duplicates or triplicates (10 µL each).…”

“…These techniques can be classified into three main categories: (i) cellular-based methods, (ii) protein-based methods and (iii) nucleic acid-based methods. Specifically, cellular-based methods such as microscopy, are commonly used for pathogen identification, but require high expertise and expensive equipment thus limited to centralized facilities [3][4][5][6][7]. Conversely, most reported protein-based methods rely on antigen-antibody detection and are typically combined with paperbased diagnostics such as lateral flow assays (LFAs) [8][9][10].…”