Mechanochemistry of Chitosan-Coated Zinc Sulfide (ZnS) Nanocrystals for Bio-imaging Applications

Abstract

The ZnS nanocrystals were prepared in chitosan solution (0.1 wt.%) using a wet ultra-fine milling. The obtained suspension was stable and reached high value of zeta potential (+57 mV). The changes in FTIR spectrum confirmed the successful surface coating of ZnS nanoparticles by chitosan. The prepared ZnS nanocrystals possessed interesting optical properties verified in vitro. Four cancer cells were selected (CaCo-2, HCT116, HeLa, and MCF-7), and after their treatment with the nanosuspension, the distribution of ZnS in the cells was studied using a fluorescence microscope. The particles were clearly seen; they passed through the cell membrane and accumulated in cytosol. The biological activity of the cells was not influenced by nanoparticles, they did not cause cell death, and only the granularity of cells was increased as a consequence of cellular uptake. These results confirm the potential of ZnS nanocrystals using in bio-imaging applications.

Synthesis and characterization of Zinc/Chitosan-Folic acid complex

“…ZnS/Chitosan sample had the ZP value of 58.63 ± 0.93 mV which is close to the values observed before for similar samples ( Bujňáková et al., 2017a ). Also, it is worth noting that ZP of ZnS/CS is much higher than that of ZnS alone (∼19 mV), indicating that these nanoparticles are more stable in the presence of chitosan ( Bujňáková et al., 2017a ). Then, the ZP of ZnS/CS-FA was measured to be 49.57 ± 1.62 mV.…”

“…This high positive value is expected for the chitosan as its pKa is ∼6.5, making it positively charged under acidic conditions. Also, much higher positive ZP values were reported earlier for chitosan under acidic conditions ( Bujňáková et al., 2017a ). ZnS/Chitosan sample had the ZP value of 58.63 ± 0.93 mV which is close to the values observed before for similar samples ( Bujňáková et al., 2017a ).…”

“…Also, much higher positive ZP values were reported earlier for chitosan under acidic conditions ( Bujňáková et al., 2017a ). ZnS/Chitosan sample had the ZP value of 58.63 ± 0.93 mV which is close to the values observed before for similar samples ( Bujňáková et al., 2017a ). Also, it is worth noting that ZP of ZnS/CS is much higher than that of ZnS alone (∼19 mV), indicating that these nanoparticles are more stable in the presence of chitosan ( Bujňáková et al., 2017a ).…”

“…In ZnS/CS sample, the peak observed at 228 nm corresponds to chitosan which is red shifted compared to pure chitosan (∼208 nm), indicating interactions between chitosan and ZnS. Then the broad peak observed from 270 nm–330 nm for ZnS/CS can be attributed to ZnS nanocrystals, which is blue shifted in comparison with bulk ZnS (343 nm) ( Bujňáková et al., 2017a ; Ghosh et al., 2006 ). On the other hand, red shifted chitosan peak was also observed for ZnS/CS-FA sample at 229 nm.…”

Mechanochemical Synthesis and Characterization of CuInS2/ZnS Nanocrystals

“…The environmental aspects of these processes are particularly attractive [24,25,26]. Several chalcogenide/ZnS nanocrystals obtained by mechanochemical synthesis by our research group was published in several papers [27,28,29,30,31,32]. Regarding to the topic of this paper–preparation of CuInS 2 /ZnS, the core-shell structures or QDs have been predominantly prepared previously e.g.…”