Mechanochemical approach for the capping of mixed core CdS/ZnS nanocrystals: Elimination of cadmium toxicity

• Published in: Journal of colloid and interface science Vol. 486; pp. 97 - 111
• Main Authors: Bujňáková, Zdenka, Baláž, Matej, Dutková, Erika, Baláž, Peter, Kello, Martin, Mojžišová, Gabriela, Mojžiš, Ján, Vilková, Mária, Imrich, Ján, Psotka, Miroslav
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15-01-2017
• Subjects: Biological Transport; Caco-2 Cells; Cadmium Compounds - chemistry; Cadmium Compounds - pharmacology; Capping; CdS/ZnS nanocrystals; Cell Survival - drug effects; Contrast Media - chemistry; Contrast Media - pharmacology; Cysteine - chemistry; Diffusion; Fluorescence; HCT116 Cells; HeLa Cells; Humans; Kinetics; l-cysteine; MCF-7 Cells; Mechanochemistry; Microscopy, Fluorescence; Nanoparticles - chemistry; Nanoparticles - ultrastructure; Particle Size; Polyvinylpyrrolidone; Povidone - chemistry; Quantum Dots - chemistry; Quantum Dots - ultrastructure; Sulfides - chemistry; Sulfides - pharmacology; Surface Properties; Suspensions; Toxicity; Zinc Compounds - chemistry; Zinc Compounds - pharmacology; Capping; CdS/ZnS nanocrystals; l-cysteine; Polyvinylpyrrolidone; Toxicity; Mechanochemistry
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2016.09.033

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The wet mechanochemical procedure for the capping of the CdS and CdS/ZnS quantum dot nanocrystals is reported. l-cysteine and polyvinylpyrrolidone (PVP) were used as capping agents. When using l-cysteine, the dissolution of cadmium(II) was almost none for CdS/ZnS nanocrystals. Moreover, prepared CdS- and CdS/ZnS-cysteine nanosuspensions exhibited unimodal particle size distributions with very good stability, which was further supported by the zeta potential measurements. The Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy showed the successful embedment of cysteine into the structure of the nanocrystals. Additionally, the optical properties were examined, and the results showed that the cysteine nanosuspension has promising fluorescence properties. On the other hand, PVP was not determined to be a very suitable capping agent for the present system. In this case, the release of cadmium(II) was higher in comparison to the l-cysteine capped samples. The nanosuspensions were successfully used for in vitro studies on selected cancer cell lines. Using fluorescence microscopy, it was evidenced that the nanocrystals enter the cell and that they can serve as imaging agents in biomedical applications.