Wong Elicia L S, Chow Edith, Gooding J Justin
School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia.
Langmuir. 2005 Jul 19;21(15):6957-65. doi: 10.1021/la050725m.
The effect of the surface chemistry of DNA recognition interfaces on DNA hybridization at a gold surface was investigated using both electrochemistry and the quartz crystal microbalance (QCM) technique. Different DNA recognition interfaces were prepared using a two-component self-assembled monolayer consisting of thiolated 20-mer probe single-stranded DNA (ss-DNA) containing either a 3'-mercaptopropyl or a 3'-mercaptohexyl linker group and an alcohol-terminated diluent layer with 2-, 6-, or 11-carbon length. The influence of the interfacial design on the hybridization efficiency, the affinity constant (Ka) describing hybridization, and the kinetics of hybridization was assessed. It was found that the further the DNA was above the surface defined by the diluent layer the higher the hybridization efficiency and Ka. The kinetics of DNA hybridization was assessed using both a QCM and an electrochemical approach to ascertain the influence of the interface on both the initial binding of target DNA to the surface and the formation of a complete duplex. These measurements showed that the length of the diluent layer has a large impact on the time taken to form a perfect duplex but no impact on the initial recognition of the target DNA by the immobilized probe DNA.
利用电化学和石英晶体微天平（QCM）技术研究了DNA识别界面的表面化学对金表面DNA杂交的影响。使用由含有3'-巯基丙基或3'-巯基己基连接基团的硫醇化20聚体探针单链DNA（ss-DNA）和具有2、6或11个碳长度的醇封端稀释层组成的双组分自组装单分子层制备了不同的DNA识别界面。评估了界面设计对杂交效率、描述杂交的亲和常数（Ka）以及杂交动力学的影响。发现DNA距离稀释层定义的表面越远，杂交效率和Ka越高。使用QCM和电化学方法评估DNA杂交动力学，以确定界面在靶DNA与表面的初始结合以及完整双链体形成方面的影响。这些测量结果表明，稀释层的长度对形成完美双链体所需的时间有很大影响，但对固定化探针DNA对靶DNA的初始识别没有影响。
