Synthesis and Spectral Studies of CdTe-Dendrimer Conjugates.

Srabanti Ghosh,Abhijit Saha

doi:10.1007/s11671-009-9339-1

Abstract

In order to couple high cellular uptake and target specificity of dendrimer molecule with excellent optical properties of semiconductor nanoparticles, the interaction of cysteine-capped CdTe quantum dots with dendrimer was investigated through spectroscopic techniques. NH2-terminated dendrimer molecule quenched the photoluminescence of CdTe quantum dots. The binding constants and binding capacity were calculated, and the nature of binding was found to be noncovalent. Significant decrease in luminescence intensity of CdTe quantum dots owing to noncovalent binding with dendrimer limits further utilization of these nanoassemblies. Hence, an attempt is made, for the first time, to synthesize stable, highly luminescent, covalently linked CdTe–Dendrimer conjugate in aqueous medium using glutaric dialdehyde (G) linker. Conjugate has been characterized through Fourier transform infrared spectroscopy and transmission electron microscopy. In this strategy, photoluminescence quantum efficiency of CdTe quantum dots with narrow emission bandwidths remained unaffected after formation of the conjugate.

Highlights

Rapid advances in nanotechnology and nanoscience have spurred interests in developing a variety of nanostructured materials
It is expected that the self-assembly of the dendrimer molecules onto NPs provide a route to modifying the NPs for targeted imaging of cancer cells [16]
The average size of CdTe QDs was found to be 3.2 nm as determined from Transmission electron microscopy (TEM) images, which is in good agreement with the size (3.0 nm) determined from the correlation of particle size and optical band gap

Summary

Introduction

Rapid advances in nanotechnology and nanoscience have spurred interests in developing a variety of nanostructured materials. Keywords Quantum dots Á Dendrimer Á Conjugate Á Infrared spectroscopy Á Luminescence A number of reports have been published in which biological molecules have been attached onto the surface of QDs. optimization of conjugation process is a prerequisite for the use of QDs in biomedical applications.

Results

Conclusion