期刊
ANALYST
卷 136, 期 23, 页码 5038-5045出版社
ROYAL SOC CHEMISTRY
DOI: 10.1039/c1an15592j
关键词
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资金
- National Natural Science Foundation of China [20705014, 20975054]
- Specialized Research Fund for the Doctoral Program of Higher Education [20070055055]
- Chinese Ministry of Education [109040]
- Fok Ying Tong Education Foundation [114041]
- Tianjin Natural Science Foundation [08JCYBJC00600]
- Program for New Century Excellent Talents [NCET-09-0482]
- Foundation for the Author of National Excellent Doctoral Dissertation of PR China [FANEDD-201023]
- Foundation for Bohai Scholar of Tianjin Normal University [5RL098, 5RL106]
Detecting a specific DNA sequence and discriminating single base-mismatch is critical to clinical diagnosis, paternity testing, forensic sciences, food and drug industry, pathology, genetics, environmental monitoring, and anti-bioterrorism. To this end, capillary electrophoresis (CE) coupled with the inductively coupled plasma mass spectrometry (ICP-MS) method is developed using the displacing interaction between the target ssDNA and the competitor Hg(2+) for the first time. The thymine-rich capture ssDNA 1 is interacted with the competitor Hg(2+), forming an assembled complex in a hairpin-structure between the thymine bases arrangement at both sides of the capture ssDNA 1. In the presence of a target ssDNA with stronger affinity than that of the competitor Hg(2+), the energetically favorable hybridization between capture ssDNA 1 and the target ssDNA destroys the hairpin-structure and releases the competitor as free Hg(2+), which was then read out and accurately quantified by CE-ICP-MS assay. Under the optimal CE separation conditions, free Hg(2+) ions and its capture ssDNA 1 adduct were baseline separated and detected on-line by ICP-MS; the increased peak intensity of free Hg(2+) against the concentration of perfectly complementary target ssDNA was linear over the concentration range of 30-600 nmol L(-1) with a limit of detection of 8 nmol L(-1) (3s, n = 11) in the pre-incubated mixture containing 1 mmol L(-1) Hg(2+) and 0.2 mmol L(-1) capture ssDNA 1. This new assay method is simple in design since any target ssDNA binding can in principle result in free Hg(2+) release by 6-fold Hg(2+) signal amplification, avoiding oligonucleotide labeling or assistance by excess signal transducer and signal reporter to read out the target. Due to element-specific detection of ICP-MS in our assay procedure, the interference from the autofluorescence of substrata was eliminated.
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