Novel synthesis of β-cyclodextrin functionalized CdTe quantum dots as luminescent probes

A novel, inexpensive procedure for the preparation of highly fluorescent and water-soluble CdTe quantum dots (QDs) using beta-cyclodextrin (beta-CD) as surface-coating agents was fabricated through the substitution reaction at the C-6 position of mono-6-deoxy-6-(p-tolylsulfonyl)-cyclodextrin (6-TsO-beta-CD) by the-NH2 of (3-aminopropyl)triethoxysilane-coated CdTe QDs (APTES/CdTe QDs) under mild conditions. X-ray powder diffraction (XRD), Fourier transform infrared spectra (FT-IR), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), ultraviolet and visible (UV-vis) spectrophotometer, and fluorescence (FL) spectrophotometer were used to characterize the obtained nanoparticles, which proved that the CdTe QDs have been effectively modified by beta-CD. The quantum yields (QYs) of CdTe QDs, APTES/CdTe QDs and beta-CD/APTES/CdTe QDs in water comparative to Rhodamine 6G were about 17%, 12%, and 9%, respectively. A pair of isomer o,p'-DDT and p,p'-DDT was chosen as the template molecules to evaluate the molecular recognition properties of beta-CD/APTES/CdTe QDs. The results revealed that beta-CD/APTES/CdTe QDs simultaneously possessed unique optical properties of QDs and excellent molecules recognition ability of beta-CD through combining their individual distinct advantages. (C) 2012 Elsevier B. V. All rights reserved.