Sensors and Biosensors Group, Department of Chemistry, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain.
Analyst. 2010 Jul;135(7):1765-72. doi: 10.1039/c000532k. Epub 2010 May 11.
In this work we report the use of an impedimetric genosensor for the model detection of H1N1 swine flu correlated DNA sequence. An oligonucleotide DNA probe, complementary to the target H1N1 virus sequence, was immobilized onto the electrode surface by covalent binding. Two different protocols, i.e. direct hybridization with the DNA target and a sandwich scheme, were employed and compared. In both cases the resulting hybrid was biotin-labelled to allow the additional conjugation with streptavidin gold nanoparticles (strept-AuNPs). The latter were used with the aim of enhancing the impedimetric signal, thus improving the sensitivity of the technique. The best limit of detection, obtained with the sandwich scheme after signal amplification step was 7.5 fmol (corresponding to 577 pmol L(-1)). Furthermore, a gold enhancement treatment was performed in order to compare the presence and distribution of gold nanoparticles onto the electrode surface. As an alternative way of visualization, streptavidin conjugate quantum dots (strept-QD) were employed to obtain fluorescence images of the DNA-biotin-strept-QD electrode surface. Finally, a comparison between impedance and microscopy was performed in terms of viability and feasibility of the techniques.
在这项工作中，我们报告了一种基于阻抗的基因传感器在模型检测 H1N1 猪流感相关 DNA 序列中的应用。通过共价键合将与靶 H1N1 病毒序列互补的寡核苷酸 DNA 探针固定在电极表面上。我们采用了两种不同的方案，即与 DNA 靶标直接杂交和三明治方案，并对它们进行了比较。在这两种情况下，所得的杂交体都被生物素标记，以允许与链霉亲和素金纳米粒子（strept-AuNPs）进一步缀合。后一种方法用于增强阻抗信号，从而提高技术的灵敏度。通过信号放大步骤后，采用三明治方案获得的最佳检测限为 7.5 fmol（相当于 577 pmol L(-1)）。此外，进行了金增强处理，以比较金纳米粒子在电极表面上的存在和分布。作为可视化的替代方法，使用链霉亲和素缀合量子点（strept-QD）来获得 DNA-生物素-链霉-QD 电极表面的荧光图像。最后，从可行性和适用性方面比较了阻抗和显微镜技术。
