Label-Free and Separation-Free Atomic Fluorescence Spectrometry-Based Bioassay: Sensitive Determination of Single-Strand DNA, Protein, and Double-Strand DNA

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• 作者：Piaopiao Chen ; Peng Wu ; Junbo Chen ; Peng Yang ; Xinfeng Zhang ; Chengbin Zheng ; Xiandeng Hou
• 刊名：Analytical Chemistry
• 出版年：2016
• 出版时间：February 16, 2016
• 年：2016
• 卷：88
• 期：4
• 页码：2065-2071
• 全文大小：477K
• ISSN：1520-6882

文摘

Based on selective and sensitive determination of Hg²⁺ released from mercury complex by cold vapor generation (CVG) atomic fluorescence spectrometry (AFS) using SnCl₂ as a reductant, a novel label-free and separation-free strategy was proposed for DNA and protein bioassay. To construct the DNA bioassay platform, an Hg²⁺-mediated molecular beacon (hairpin) without labeling but possessing several thymine (T) bases at both ends was employed as the probe. It is well-known that Hg²⁺ could trigger the formation of the hairpin structure through T–Hg²⁺–T connection. In the presence of a specific target, the hairpin structure could be broken and the captured Hg²⁺ was released. Interestingly, it was found that SnCl₂ could selectively reduce only free Hg²⁺ to Hg⁰ vapor in the presence of T–Hg²⁺–T complex, which could be separated from sample matrices for sensitive AFS detection. Three different types of analyte, namely, single-strand DNA (ssDNA), protein, and double-strand DNA (dsDNA), were investigated as the target analytes. Under the optimized conditions, this bioassay provided high sensitivity for ssDNA, protein, and dsDNA determination with the limits of detection as low as 0.2, 0.08, and 0.3 nM and the linear dynamic ranges of 10–150, 5–175, and 1–250 nM, respectively. The analytical performance for these analytes compares favorably with those by previously reported methods, demonstrating the potential usefulness and versatility of this new AFS-based bioassay. Moreover, the bioassay retains advantages of simplicity, cost-effectiveness, and sensitivity compared to most of the conventional methods.