Alkaline Post-Treatment of Cd(II)–Glutathione
Coordination Polymers: Toward Green Synthesis of Water-Soluble and
Cytocompatible CdS Quantum Dots with Tunable Optical Properties
- Publication date
- Publisher
Abstract
In this study, we demonstrate a facile
and environmentally friendly
method for the synthesis of glutathione (GSH)-capped water-soluble
CdS quantum dots (QDs) with a high cytocompatibility and a tunable
optical property based on alkaline post-treatment of Cd–GSH
coordination polymers (CPs). Cd–GSH CPs are synthesized with
the coordination reaction of Cd<sup>2+</sup> with GSH at different
pH values, and the CdS QDs are then formed by adding NaOH to the aqueous
dispersion of the Cd–GSH CPs to break the coordination interaction
between Cd<sup>2+</sup> and GSH with the release of sulfur. The particle
size and optical property of the as-formed CdS QDs are found to be
easily tailored by simply adjusting the starting pH values of GSH
solutions used for the formation of Cd–GSH CPs, in which the
wavelengths of trap-state emission of the QDs red-shift with an increase
in the sizes of the QDs that is caused by an increase in the starting
pH values of GSH solutions. In addition, the use of GSH as the capping
reagent eventually endows the as-formed CdS QDs with enhanced water
solubility and good cytocompatibility, as demonstrated with HeLa cells.
The method demonstrated here is advantageous in that the cadmium precursor
and the sulfur source are nontoxic and easily available, and the size,
optical properties, water solubility, and cytocompatibilty of the
as-formed CdS QDs are simply achieved and experimentally regulated.
This study offers a new and green synthetic route to water-soluble
and cytocompatible CdS QDs with tunable optical properties