Label-Free Liquid Crystal Biosensor Based on Specific Oligonucleotide Probes for Heavy Metal Ions

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• 作者：Shengyuan Yang ; Chao Wu ; Hui Tan ; Yan Wu ; Shuzhen Liao ; Zhaoyang Wu ; Guoli Shen ; Ruqin Yu
• 刊名：Analytical Chemistry
• 出版年：2013
• 出版时间：January 2, 2013
• 年：2013
• 卷：85
• 期：1
• 页码：14-18
• 全文大小：354K
• 年卷期：v.85,no.1(January 2, 2013)
• ISSN：1520-6882

文摘

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 Hg²⁺ 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 Hg²⁺, 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 Hg²⁺ 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.