title: Label-free liquid crystal biosensor based on specific oligonucleotide probes for heavy metal ions.
abstract: In this study, to enhance the capability of metal ions disturbing the orientation of liquid crystals (LCs), we designed a new label-free LC biosensor for the highly selective and sensitive detection of heavy metal ions. This strategy makes use of the target-induced DNA conformational change to enhance the disruption of target molecules for the orientation of LC leading to an amplified optical signal. The Hg(2+) ion, which possesses a unique property to bind specifically to two DNA thymine (T) bases, is used as a model heavy metal ion. In the presence of Hg(2+), the specific oligonucleotide probes form a conformational reorganization of the oligonucleotide probes from hairpin structure to duplex-like complexes. The duplex-like complexes are then bound on the triethoxysilylbutyraldehyde/N,N-dimethyl-N-octadecyl (3-aminopropyl) trimethoxysilyl chloride (TEA/DMOAP)-coated substrate modified with capture probes, which can greatly distort the orientational profile of LC, making the optical image of LC cell birefringent as a result. The optical signal of LC sensor has a visible change at the Hg(2+) concentration of low to 0.1 nM, showing good detection sensitivity. The cost-effective LC sensing method can translate the concentration signal of heavy metal ions in solution into the presence of DNA duplexes and is expected to be a sensitive detection platform for heavy metal ions and other small molecule monitors.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, PR China.
authors.forename: Shengyuan
authors.initials: S
authors.lastname: Yang
authors.forename: Chao
authors.initials: C
authors.lastname: Wu
authors.forename: Hui
authors.initials: H
authors.lastname: Tan
authors.forename: Yan
authors.initials: Y
authors.lastname: Wu
authors.forename: Shuzhen
authors.initials: S
authors.lastname: Liao
authors.forename: Zhaoyang
authors.initials: Z
authors.lastname: Wu
authors.forename: Guoli
authors.initials: G
authors.lastname: Shen
authors.forename: Ruqin
authors.initials: R
authors.lastname: Yu
mesh_terms: D015374:Biosensing Techniques; D004247:DNA / Q000737:chemistry; D007477:Ions / Q000737:chemistry; D050866:Liquid Crystals / Q000737:chemistry*; D008628:Mercury / Q000032:analysis*; D015345:Oligonucleotide Probes / Q000737:chemistry*; D013941:Thymine / Q000737:chemistry
chemical_list: D007477:Ions; D015345:Oligonucleotide Probes; D004247:DNA; D008628:Mercury; D013941:Thymine