title: 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.
authors.affiliation: Department of Polymer Science &Engineering, Polymeric Nanomaterials Laboratory, School of Applied Chemical Engineering, Kyungpook National University, #1370 Sangyuk-dong, Buk-gu, Daegu 41566, Korea.
authors.forename: Mashooq
authors.initials: M
authors.lastname: Khan
authors.affiliation: School of Applied Biosciences, Kyungpook National University, #1370 Sangyuk-dong, Buk-gu, Daegu 41566, Korea.
authors.forename: Abdur Rahim
authors.initials: AR
authors.lastname: Khan
authors.affiliation: School of Applied Biosciences, Kyungpook National University, #1370 Sangyuk-dong, Buk-gu, Daegu 41566, Korea.
authors.forename: Jae-Ho
authors.initials: JH
authors.lastname: Shin
authors.affiliation: Department of Polymer Science &Engineering, Polymeric Nanomaterials Laboratory, School of Applied Chemical Engineering, Kyungpook National University, #1370 Sangyuk-dong, Buk-gu, Daegu 41566, Korea.
authors.forename: Soo-Young
authors.initials: SY
authors.lastname: Park
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004277:DNA, Single-Stranded / Q000032:analysis*; D050866:Liquid Crystals; D016973:Pectobacterium carotovorum / Q000235:genetics; D000644:Quaternary Ammonium Compounds; D012232:Rhizoctonia / Q000235:genetics; D012680:Sensitivity and Specificity
chemical_list: D004277:DNA, Single-Stranded; D000644:Quaternary Ammonium Compounds; C013912:decyltrimethylammonium