AbstractThe authors describe a rapid method for the detection of the Escherichia coli O157:H7 (E. coli O157:H7) bacterial gene. The DNA sandwich-hybridization impedimetric assay is based on the use of a nanoporous alumina membrane in combination with gold/silver core/shell nanoparticles (Ag@AuNPs) that act as tags for impedance signal amplification. The probe oligonucleotides were immobilized on the walls of the nanopores. This is followed by hybridization, first with target (analyte), then with reporter oligonucleotides labeled with Ag@AuNP tags. The impedimetric signal results from target oligo hybridization with probe oligos and co-hybridization with labeled reporter oligos, which increases the blocking degree of the nanopores. The assays were tested with membranes in nanopore sizes of 20 nm, 50 nm and 100 nm. The assay performs best in case of 100 nm nanopores where the limit of detection is as low as 11 pM, with a linear detection range that extends from 50 pM to 200 nM. This indicates its potential for rapid and ultrasensitive gene detection. Graphical abstractSchematic of a nanoporous alumina membrane based DNA sandwich-hybridization assay of bacteria gene with gold/silver core/shell nanoparticle (Ag@AuNP) tags. Red, green and purple wavy lines represent probe oligos, target oligos and reporter oligos, respectively. Pink ball with grey shell represents the Ag@AuNP.

中文翻译：

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基于使用纳米多孔氧化铝膜的大肠杆菌 O157:H7 基因超灵敏 DNA 夹心杂交试验中孔径的影响

摘要作者描述了一种用于检测大肠杆菌 O157:H7 (E.coli O157:H7) 细菌基因的快速方法。DNA 夹心杂交阻抗测定基于使用纳米多孔氧化铝膜与金/银核/壳纳米粒子 (Ag@AuNPs) 结合作为阻抗信号放大的标签。探针寡核苷酸固定在纳米孔的壁上。接着是杂交，首先是目标（分析物），然后是用 Ag@AuNP 标签标记的报告寡核苷酸。阻碍信号来自目标寡核苷酸与探针寡核苷酸杂交以及与标记报告寡核苷酸的共杂交，这增加了纳米孔的封闭程度。使用20 nm、50 nm和100 nm纳米孔径的膜对这些测定进行了测试。该测定在 100 nm 纳米孔的情况下表现最佳，其中检测限低至 11 pM，线性检测范围从 50 pM 扩展到 200 nM。这表明其具有快速和超灵敏基因检测的潜力。带有金/银核/壳纳米颗粒 (Ag@AuNP) 标签的基于纳米多孔氧化铝膜的细菌基因 DNA 夹心杂交测定示意图。红色、绿色和紫色波浪线分别代表探针寡核苷酸、目标寡核苷酸和报告寡核苷酸。带灰色外壳的粉红色球代表 Ag@AuNP。带有金/银核/壳纳米颗粒 (Ag@AuNP) 标签的基于纳米多孔氧化铝膜的细菌基因 DNA 夹心杂交测定示意图。红色、绿色和紫色波浪线分别代表探针寡核苷酸、目标寡核苷酸和报告寡核苷酸。带灰色外壳的粉红色球代表 Ag@AuNP。带有金/银核/壳纳米颗粒 (Ag@AuNP) 标签的基于纳米多孔氧化铝膜的细菌基因 DNA 夹心杂交测定示意图。红色、绿色和紫色波浪线分别代表探针寡核苷酸、目标寡核苷酸和报告寡核苷酸。带灰色外壳的粉红色球代表 Ag@AuNP。