期刊
BIOSENSORS & BIOELECTRONICS
卷 73, 期 -, 页码 181-187出版社
ELSEVIER ADVANCED TECHNOLOGY
DOI: 10.1016/j.bios.2015.05.068
关键词
DNA biosensor; E. coli; Latex; Voltammetry; Nanoparticle
类别
资金
- NANOTEC [P-110022]
- Higher Education Research Promotion and National Research University Project of Thailand, Office of the Higher Education Commission [57000703]
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. 3.5 x 10(5) anti-DIG antibodies. The voltammetric label is a hollow polyelectrolyte shell containing approx. 1.0 x 10(11) 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 mL(-1) in an assay time of approx. 140 min. (C) 2015 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据