Abstract
This paper presents a modification of the surface of CdS/ZnS and CdSexS1−x/ZnS quantum dots (QDs) with 3-mercaptopropionic and 6-mercaptohexanoic acid. The obtained QDs were characterized using TEM, DLS, UV–Vis, and fluorescence spectroscopy. Flow cytometry was applied to evaluate the cytotoxicity of QDs and examine the type of death caused by the tested nanoparticles. In addition, the generation of reactive oxygen species after incubation of the tested cells with CdSexS1−x/ZnS–MPA and CdSexS1−x/ZnS–MHA QDs was evaluated. The study was conducted on three cell lines: adherent (A549 and MRC-5) and suspension ones (K562). The conducted research demonstrated that the tested nanoparticles exhibit concentration-dependent toxicity. It was observed that the surface modification influences the toxicity level of the examined QDs, and modification of their surface with the use of the ligand of longer carbon chain (MHA) reduces the toxicity in comparison with QDs–MPA. It was also found that all tested QDs caused the death of cells in the course of necrosis. Based on obtained results, it was concluded that the cytotoxicity of QDs is to a large extent related to reactive oxygen species (ROS) generation.
Highlights
Quantum dots (QDs) are non-organic fluorescent semiconductor nanocrystals, which usually consist of a core and a shell
We described the research on the cytotoxicity of core/shell CdSe/ZnS and C dSexS1−x/ZnS quantum dots modified with two different surface ligands: 3-mercaptopropionic acid (MPA) and 6-mercaptohexanoic acid (MHA)
High-quality quantum dots consisting of a core of a cadmium-based salt (CdS or CdSe) and a coat of ZnS obtained by organometallic synthesis are the most popular fluorescent nanocrystals
Summary
Quantum dots (QDs) are non-organic fluorescent semiconductor nanocrystals, which usually consist of a core and a shell. QDs possess preferable optical properties in comparison with organic fluorophores. These include more intensive and stable fluorescence, narrow, and symmetric emission peaks and broad absorption spectra (Huy et al 2018; Zhou et al 2015). One of the advantages of QDs is a possibility to conjugate a large number of different substances including peptides, aptamers, or antibodies to their surface (Chandan et al 2018). It can influence on the QD-conjugated cellular
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