Studies On The Interaction Machanism Of Aunps And CdTe QDs

Gold nanoparticles (AuNPs) have been widely used in the fields of biosensor, biologicalimaging and diagnostics as its prominent virtues including optical, electrical, chemicalcharacteristics as well as excellent biocompatibility. Quantum dots (QDs) are a kind ofsemiconductor nanocrystals restricted in three-dimension. The incomparable luminescenceproperties of QDs to traditional organic dyes have stimulated the increasing attention ofreseachers in various fields in recent years. In this paper, a series of studies have been lauchedbased on the interaction between AuNPs and CdTe QDs.1. Different sizes of AuNPs (5nm,13nm,21nm) were separately synthesized andwater-soluble CdTe QDs (2.8nm) was prepared. The synthesized nanoparticles werecharacterized by TEM, UV-vis absorption spectroscopy, fluorescence emission spectrum andX-ray diffraction so on. The results showed that the products have good dispersibility,uniform size and stable photochemical properties.2. With the aids of Au-S bond and amido bond, single-stranded DNA molecules wereconnected to the surface of AuNPs (13nm) and CdTe QDs, respectively. The modifiednanoparticles were characterized by TEM, UV-vis absorption spectroscopy, fluorescenceemission spectrum and dynamic light scattering (DLS) so on.3. The interaction of three sizes AuNPs with CdTe QDs were investigated byfluorescence emission spectrum. Moreover, the interaction mechanism of AuNPs with CdTeQDs was elucidated with the modified Stern-Volmer equation and fluorescence resonanceenergy transfer (FRET) theory. The results indicated that the interaction mechanism isrelatively complex. It may be concluded that there is mainly energy transfer, also there may beelectron transfer and so on. 4. To further reveal the interaction machanism of AuNPs with CdTe QDs, the modifiedAuNPs and QDs by connecting single-stranded DNA molecules were employed in this study.The experimental results showed that the fluorescence quenching efficiency is higher and thequenching effect is more obvious when the single-stranded DNA molecules arecomplementary. It is mainly due to DNA hybridization reaction, leading to be closer eachother for AuNPs and QDs.