Chemistry and Geochemistry Department, Colorado School of Mines, Golden, Colorado 80401, United States.
ACS Appl Mater Interfaces. 2011 Sep;3(9):3285-92. doi: 10.1021/am200604q. Epub 2011 Aug 25.
The amine density of 3-aminopropyldimethylethoxysilane (APDMES) films on silica is controlled to determine its effect on DNA probe density and subsequent DNA hybridization. The amine density is tailored by controlling the surface reaction time of (1) APDMES, or (2) n-propyldimethylchlorosilane (PDMCS, which is not amine terminated) and then reacting it with APDMES to form a mixed monolayer. High-resolution X-ray photoelectron spectroscopy (XPS) is used to quantify silane surface coverage of both pure and mixed monolayers on silica; the XPS data demonstrate control of amine density in both pure APDMES and PDMCS/APDMES mixed monolayers. A linear correlation between the atomic concentration of N atoms from the amine and Si atoms from the APDMES in pure APDMES films allows us to calculate the PDMCS/APDMES ratio in the mixed monolayers. Fluorescence from attached DNA probes and from hybridized DNA decreases as the percentage of APDMES in the mixed monolayer is decreased by dilution with PDMCS.
通过控制 3-氨丙基二甲基乙氧基硅烷（APDMES）在二氧化硅上的胺密度来确定其对 DNA 探针密度和随后的 DNA 杂交的影响。通过控制（1）APDMES 的表面反应时间或（2）n-丙基二甲基氯硅烷（PDMCS，其末端不是胺）的表面反应时间，并随后用 APDMES 与之反应来形成混合单层，从而调节胺密度。高分辨率 X 射线光电子能谱（XPS）用于定量二氧化硅上纯单层和混合单层的硅烷表面覆盖率；XPS 数据表明，在纯 APDMES 和 PDMCS/APDMES 混合单层中都可以控制胺密度。在纯 APDMES 膜中，从胺的 N 原子和 APDMES 的 Si 原子的原子浓度之间存在线性相关性，这使得我们可以计算混合单层中 PDMCS/APDMES 的比例。随着混合单层中 APDMES 百分比通过与 PDMCS 的稀释而降低，附着的 DNA 探针和杂交的 DNA 的荧光强度也随之降低。
