کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7231361 | 1470956 | 2016 | 21 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Enzyme-triggered formation of enzyme-tyramine concatamers on nanogold-functionalized dendrimer for impedimetric detection of Hg(II) with sensitivity enhancement
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موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آنالیزی یا شیمی تجزیه
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چکیده انگلیسی
A new impedimetric sensing strategy based on enzyme-triggered formation of enzyme-tyramine concatamers on the nanogold-functionalized poly(amidoamine) (PAMAM) dendrimer was designed for sensitive detection of mercury(II) (Hg2+) ion, coupling with enzymatic biocatalytic precipitation towards 4-choloro-1-naphthol (4-CN) on thymine (T)-rich single-stranded DNA1-modified electrode. Initially, nanogold-decorated PAMAM dendrimer (AuNP-PAMAM) was synthesized by the in-situ reduction method, and then functionalized with horseradish peroxidase (HRP) and another T-rich oligomer (DNA2). Upon target Hg2+ introduction, probe DNA2 on the AuNP-PAMAM bound to the DNA1 on the electrode owing to the T-Hg2+-T coordination chemistry between the two DNA strands. Accompanying the AuNP-PAMAM, the carried HRP could trigger the formation of HRP-tyramine concatamer via the classical tyramine signal amplification strategy in the presence of HRP-tyramine conjugates and hydrogen peroxide. The concatenated HRP molecules in the concatamer catalyzed the 4-CN oxidation to produce an insoluble precipitation on the electrode, thereby resulting in the local alteration in the conductivity. Under optimal conditions, two signal-generation tags including HRP-AuNP-DNA2 and HRP-AuNP-PAMAM-DNA2 with or without tyramine signal amplification strategy (i.e., four schemes) were used for impedimetric detection of target Hg2+ on the basis of the same assay format. A low detection limit (LOD) of 0.4Â pM and a wide dynamic working range of 0.001-100Â nM Hg2+ by using HRP-AuNP-PAMAM-DNA2 with tyramine signal amplification strategy were obtained in comparison with those of other strategies. The assay had a good repeatability and showed an intermediate precision of down to 9.6%. In addition, the methodology also exhibited high specificity and selectivity towards target Hg2+ against other metal ions, and was applicable for monitoring Hg2+ in the spiked drinking water samples.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biosensors and Bioelectronics - Volume 75, 15 January 2016, Pages 108-115
Journal: Biosensors and Bioelectronics - Volume 75, 15 January 2016, Pages 108-115
نویسندگان
Zhenli Qiu, Dianyong Tang, Jian Shu, Guonan Chen, Dianping Tang,