Milkani Eftim, Khaing Aung M, Morais Sergi, Lambert Christopher R, McGimpsey W Grant
Chemistry and Biochemistry, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, USA.
Bioengineering Institute, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, USA.
Anal Methods. 2011 Jan 1;3(1):122-132. doi: 10.1039/c0ay00492h.
The detection and characterization of the hybridization event of 21-base, unlabeled DNA oligonucleotides with a monolayer of complementary DNA immobilized on a gold surface, by electrochemical impedance spectroscopy and surface plasmon resonance (SPR) is presented. A thiol modification on the probe DNA strand allowed for its attachment to the surface via self-assembly. For the hybridization of full match target DNA a detection limit of 20 pM was determined. RNA hybridization was also detectable with the same sensor, with a similar detection limit. The SPR signal generated upon hybridization of the full match was always distinguishable from the single mismatch target DNA oligonucleotides when the mismatch was in the middle or at the proximal end of the target DNA sequence. However, the response of the sensor was identical for the hybridization of the full match and the distal end mismatch. The SPR sensor described is reusable over at least 20 hybridization/regeneration cycles and is insensitive to flow rate (20-800 µL min-1) or temperature (20-60 °C). Based on the SPR response, the surface density of the probe was estimated to be at least 4.3 × 1012 molecules per cm2.
本文介绍了通过电化学阻抗谱和表面等离子体共振（SPR）对21个碱基的未标记DNA寡核苷酸与固定在金表面的单链互补DNA杂交事件进行检测和表征的方法。探针DNA链上的硫醇修饰使其能够通过自组装附着在表面。对于完全匹配的目标DNA杂交，检测限为20 pM。使用相同的传感器也可检测RNA杂交，检测限相似。当错配位于目标DNA序列的中间或近端时，完全匹配杂交产生的SPR信号始终与单碱基错配的目标DNA寡核苷酸可区分。然而，对于完全匹配和远端错配的杂交，传感器的响应是相同的。所描述的SPR传感器至少可重复使用20个杂交/再生循环，并且对流速（20 - 800 μL min-1）或温度（20 - 60 °C）不敏感。基于SPR响应，估计探针的表面密度至少为每平方厘米4.3×1012个分子。
