Controlling DNA orientation on mixed ssDNA/OEG SAMs
Controlling DNA orientation on mixed ssDNA/OEG SAMs
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DOI：
10.1021/la052908e
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发表时间：
2006-05-09
期刊：
影响因子：
3.9
通讯作者：
Jiang, SY
中科院分区：
文献类型：
--
作者：
Boozer, C;Chen, SF;Jiang, SY
我们提出并表征了由单链寡核苷酸（ssDNA）和寡聚（乙二醇）（OEG）封端的硫醇组成的混合自组装单层（SAM）。 ssDNA/OEG SAM 通过同时共吸附多种成分的常见硫醇溶液来制备。化学分析电子能谱 (ESCA) 用于测量 ssDNA 的表面覆盖度，而表面等离子共振 (SPR) 传感器用于测量互补 ssDNA 的杂交和蛋白质抗性。通过这些技术的互补使用，我们发现组装溶液中OEG的成分控制着一个关键参数：ssDNA在表面上的表面覆盖率。有证据表明它会影响固定 ssDNA 探针的方向。较低的 OEG 浓度产生的表面具有较高的 ssDNA 覆盖率和较不利的方向，而较高的 OEG 浓度产生的表面具有较低的 DNA 覆盖率和较有利的方向。这两种效应之间的竞争控制着 ssDNA 表面的杂交效率。与使用其他稀释剂硫醇制备的ssDNA表面相比，OEG的使用提高了表面的蛋白质耐受性，使其具有更广泛的适用性。
We present and characterize a mixed self-assembled monolayer (SAM) consisting of single-stranded oligonucleotide (ssDNA)-and oligo(ethylene glycol) (OEG)-terminated thiols. The ssDNA/OEG SAMs are prepared by simultaneous coadsorption from a common thiol solution over a broad range of compositions. Electron spectroscopy for chemical analysis (ESCA) is used to measure the surface coverage of ssDNA, whereas surface plasmon resonance (SPR) sensor is used to measure the hybridization of complementary ssDNA and protein resistance. Through the complementary use of these techniques, we find that the composition of OEG in the assembly solution controls a key parameter: the surface coverage of ssDNA on the surface. There is evidence that it influences the orientation of the immobilized ssDNA probes. Lower OEG concentrations yield a surface with higher ssDNA coverage and less favorable orientation, whereas higher OEG concentrations produce a surface with lower DNA coverage and more favorable orientation. Competition between these two effects controls the hybridization efficiency of the ssDNA surface. Compared to ssDNA surfaces prepared with other diluent thiols, the use of OEG improves the protein resistance of the surface, making it more broadly applicable.