Original Paper

Journal of Fluorescence

, Volume 22, Issue 1, pp 193-199

Microwave-Assisted Aqueous Synthesis of Highly Luminescent Carboxymethyl Chitosan-Coated CdTe/CdS Quantum Dots as Fluorescent Probe for Live Cell Imaging

  • Zhenyu HeAffiliated withCollege of Resource and Environmental Science, Wuhan UniversityWuhan Centers for Disease Prevention and Control
  • , Honghao ZhuAffiliated withWuhan Centers for Disease Prevention and Control
  • , Peijiang ZhouAffiliated withCollege of Resource and Environmental Science, Wuhan University Email author 

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Abstract

This paper describes the development of a simplified and rapid method for the aqueous synthesis of quantum dots (QDs) with CdTe cores and gradient CdS external shells (CdTe/CdS QDs) aided by microwave irradiation. Several synthesis parameters, such as molar ratio of reagents, pH, reaction temperature, and reaction time, were studied in details. Under the optimized conditions, highly effective CdTe/CdS QDs could be synthesized in aqueous phase in only 15 min. In order to improve the biocompatibility of the CdTe/CdS QDs, these QDs were then interacted with carboxymethyl chitosan (CMC) so as they could be used as fluorescent probes in the aqueous phase. With the incorporation of CMC, the stability of modified QDs was found to have improved significantly (from 4 months to more than 10 months at room temperature). The photoluminescence quantum yield (PLQY) of the modified QDs could reach 75%, other parameters include a full width at half maximum of the emission (FWHM) spectrum as 40 ~ 60 nm, and an average size, estimated from electron microscopic images, as 3.5 nm. As fluorescent probes, these modified QDs were successfully used for imaging live Madin–Darby canine kidney (MDCK) cells, in which the preliminary results indicated that these modified QDs demonstrated good biocompatibility and showed promising applications for bio-labeling and imaging.

Keywords

Quantum dots Aqueous synthesis Carboxymethyl chitosan Biological fluorescent labeling