On the structure and desorption dynamics of DNA bases adsorbed on gold:: A temperature-programmed study
On the structure and desorption dynamics of DNA bases adsorbed on gold:: A temperature-programmed study
复制标题
DOI：
10.1021/jp051617b
复制
发表时间：
2005-08-11
影响因子：
3.3
通讯作者：
Mirkin, CA
中科院分区：
文献类型：
--
作者：
Östblom, M;Liedberg, B;Mirkin, CA
利用程序升温解吸-红外反射吸收光谱（TPD-IRAS）和程序升温解吸-质谱（TPD-MS）研究了多晶金薄膜上腺嘌呤、胞嘧啶、鸟嘌呤和胸腺嘧啶的单层和多层样品的结构和解吸动力学。结果表明，嘧啶、腺嘌呤和鸟嘌呤以复杂的方式吸附到金上，并且粘附性（腺嘌呤）和内聚性（鸟嘌呤）相互作用为基材表面提供了表观结合能。腺嘌呤显示出至少两个吸附位点，包括一个高能位点（210 摄氏度，类似于 136 kJ/mol），其中分子通过 NH2 基团以类似 sp(3) 的、强烈扰动的非平面构型与金底物配位。嘌呤、胞嘧啶和胸腺嘧啶表现出不太复杂的吸附/解吸行为。胞嘧啶的解吸能（160 摄氏度，类似于 122 kJ/mol）与腺嘌呤和鸟嘌呤获得的解吸能相似，但解吸发生在分散的、非聚集的胞嘧啶的单个位点。胸腺嘧啶也从单个位点解吸，但能量显着降低（100 摄氏度，类似于 104 kJ/mol）。红外数据表明，本文讨论的单层结构在结构上与在块状结晶状态下观察到的单层结构非常不同。同样明显的是，嘧啶和嘌呤都吸附在金上，分子平面相对于基底表面呈非平行方向。这项工作的结果是在提高对生物分析应用（特别是基于金纳米颗粒的测定）捕获寡核苷酸或 DNA 链的设计的理解的背景下讨论的。
The structure and desorption dynamics of mono- and multilayer samples of adenine, cytosine, guanine, and thymine on polycrystalline gold thin films are studied using temperature-programmed desorption-infrared reflection absorption spectroscopy (TPD-IRAS) and temperature-programmed desorption-mass spectroscopy (TPD-MS). It is shown that the pyrimidines, adenine and guanine, adsorb to gold in a complex manner and that both adhesive (adenine) and cohesive (guanine) interactions contribute the apparent binding energies to the substrate surface. Adenine displays at least two adsorption sites, including a high-energy site (210 degrees C, similar to 136 kJ/mol), wherein the molecule coordinates to the gold substrate via the NH2 group in an sp(3)-like, strongly perturbed, nonplanar configuration. The purines, cytosine and thymine, display a less complicated adsorption/desorption behavior. The desorption energy for cytosine (160 degrees C, similar to 122 kJ/mol) is similar to those obtained for adenine and guanine, but desorption occurs from a single site of dispersed, nonaggregated cytosine. Thymine desorbs also from a single site but at a significantly lower energy (100 degrees C, similar to 104 kJ/mol). Infrared data reveal that the monolayer architectures discussed herein are structurally very different from those observed for the bases in the bulk crystalline state. It is also evident that both pyrimidines and purines adsorb on gold with the plane of the molecule in a nonparallel orientation with respect to the substrate surface. The results of this work are discussed in the context of improving the understanding of the design of capturing oligonucleotides or DNA strands for bioanalytical applications, in particular, for gold nanoparticle-based assays.