کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7231692 | 1470958 | 2015 | 32 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Highly sensitive electrochemical detection of genomic DNA based on stem loop probes structured for magnetic collection and measurement via metalised hollow polyelectrolyte shells
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آنالیزی یا شیمی تجزیه
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چکیده انگلیسی
We report a highly sensitive method for the electrochemical detection of genomic DNA, based on the employment of two sub-micron oligonucleotide labels - one for magnetic collection and the other for voltammetric detection - and their incorporation onto a stem loop DNA probe. The magnetic label consists of a latex particle of mean diameter 441±6 nm, bearing magnetic Fe3O4 particles and approx. 3.5Ã105 anti-DIG antibodies. The voltammetric label is a hollow polyelectrolyte shell containing approx. 1.0Ã1011 Au atoms in the form of well dispersed Au nanoparticles. A DIG tag on one arm of the stem loop enables binding to the magnetic label, while a thiol tag on the other arm enables attachment to the Au nanoparticles. Due to steric hindrance from the two relatively large labels, attachment of both moieties is dependant on target-probe hybridisation straightening the loop. Once attached, sensitive DNA measurement is facilitated by magnetic collection of the DNA into a small volume and by the high quantity of Au atoms available for detection. Using differential pulse anodic stripping voltammetry we calibrated a 30 mer sequence common to 71 strains of Escherichia coli across the concentration range from 0.1 aM to 100 pM with a LOD of 1.8 aM. Three strains of E. coli, BL 21, ATCC8739, O157:H7, when spiked into UHT milk and fermented palm juice, could be detected with LODs of approx. 2-4 CFU mLâ1 in an assay time of approx. 140 min.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biosensors and Bioelectronics - Volume 73, 15 November 2015, Pages 181-187
Journal: Biosensors and Bioelectronics - Volume 73, 15 November 2015, Pages 181-187
نویسندگان
Naphat Khunrattanaporn, Patsamon Rijiravanich, Mithran Somasundrum, Werasak Surareungchai,