%0 Journal Article
%T Self-Assemblies of Single-Walled Carbon Nanotubes through Tunable Tethering of Pyrenes by Dextrin for Rapidly Chiral Sensing
%A Wei-Li Wei
%A Qiushui Chen
%A Haifang Li
%A Jin-Ming Lin
%J International Journal of Analytical Chemistry
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/862692
%X Pyrene-modified dextrin (Py-Dex) was synthesized via the Schiff base reaction between reducing end of dextrins and 1-aminopyrene, and then self-assemblies of single-walled carbon nanotubes (SWNTs) were fabricated through the tunable tethering of pyrene to SWNTs by dextrin chains. The Py-Dex-SWNTs assemblies were found to be significantly water-soluble because of the synergistic effect of dextrin chains and pyrene moieties. Py-Dex and Py-Dex-SWNTs were adequately characterized by NMR, UV-vis, fluorescence spectroscopy, Raman spectroscopy, matrix-assisted laser desorption/ionization-time of flight mass spectroscopy, and transmission electron microscopy. The tethering effect of dextrin toward pyrene moieties was clearly revealed and was found to be tunable by adjusting the length of dextrin chains. The fluorescence of pyrene moieties was sufficiently quenched by SWNTs with the support of dextrin chains. Furthermore, the Py-Dex-SWNTs assemblies were used for chiral selective sensing by introducing cyclodextrins as chiral binding sites. The rapid chiral sensing was successfully tested for different enantiomers. 1. Introduction Chirality plays an important role in various fields such as pharmaceuticals and biotechnology. The booming development of chirality researches demands rapid and sensitive analytical tools for chiral assays. During the past several decades, numerous studies have been focused on chiral analysis resulting in various techniques including various types of chromatography [1], capillary electrophoresis [2, 3], and chiral sensors [4]. Amongst those methods, the use of fluorescence has attracted much interest because it can offer the advantages of real-time analysis, high sensitivity, multiple sensing modes, and remote detection capabilities [5]. Chiral selective fluorescent methods are especially useful for the rapid and high-throughput assay of the enantiomeric composition of chiral substrates [6]. Generally, such a fluorescent method composed of a fluorophore and a chiral binding site. The chirality of the binding site could be achieved by introducing chiral selectors into the binding site. Significantly, some chiral cyclic compounds such as crown ethers, calixarenes, and cyclodextrins (CDs) have been found to be versatile chiral selectors through chiral selective inclusion. Thus, these compounds could be fabricated into fluorescence sensors for chiral recognition. On the other hand, as a result of the extraordinary chemical, electronic, and mechanical properties of single-walled carbon nanotubes (SWNTs), SWNTs-mediated self-assemblies are
%U http://www.hindawi.com/journals/ijac/2011/862692/