Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel.
Langmuir. 2013 Jan 8;29(1):191-8. doi: 10.1021/la303828s. Epub 2012 Dec 17.
The work reported herein describes the controlled creation of uniform thiol-functionalized siloxane-anchored self-assembled monolayers (SAMs) and their selective transformation into intramonolayer (bridging) disulfides. These disulfides provide for the efficient immobilization of (bio)molecules bearing pendant thiols or disulfides, with no need for added oxidant. The unambiguous development of this surface chemistry required analytical methods that distinguish thiol and disulfide moieties on a surface. Physical properties such as wetting and monolayer thickness do not suffice nor do routine spectroscopic techniques (e.g., XPS, IR). Therefore, a method for distinguishing and quantifying thiol and disulfide surface functionality on a monolayer array based on the reaction with 2,4-dinitrofluorobenzene (DNFB, Sanger's reagent) is reported. DNFB readily reacts with thiol-SAMs (but not with disulfides) to form stable derivatives with distinctive IR, UV, and XPS signatures. Finally, the thiol-disulfide chemistry is applied to thiol-functionalized hybrid silica nanoparticles. These high-surface-area nanoparticles provide solid supports heavily loaded with thiol groups whose chemistry is also reported herein.
本文所述的工作是对均匀硫醇功能化硅氧烷锚定自组装单层（SAM）的可控合成及其选择性转化为层内（桥接）二硫键的研究。这些二硫键可有效固定带有侧链硫醇或二硫键的（生物）分子，无需添加氧化剂。明确开发这种表面化学需要能够区分表面上硫醇和二硫键部分的分析方法。润湿性和单层厚度等物理性质以及常规光谱技术（例如 XPS、IR）都不够。因此，本文报道了一种基于与 2,4-二硝基氟苯（DNFB，桑格试剂）反应来区分和定量单层阵列上硫醇和二硫键表面官能团的方法。DNFB 可与硫醇-SAMs（而不是二硫键）快速反应，形成具有独特 IR、UV 和 XPS 特征的稳定衍生物。最后，将硫醇-二硫键化学应用于硫醇功能化杂化二氧化硅纳米粒子。这些高表面积的纳米粒子提供了大量负载硫醇基团的固体载体，其化学性质也在本文中报道。
