Comparative studies of biological activity of cadmium-based quantum dots with different surface modifications

Abstract

This paper presents a modification of the surface of CdS/ZnS and CdSe x S 1−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 CdSe x S 1−x / ZnS-MPA and CdSe x S 1−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.

New insights into the safety assessment of quantum dots: potential release pathways, environmental transformations, and health risks

“…302–305 CdTe QDs can trigger mitochondrial dysfunction in hepatocytes via ROS, leading to apoptosis, 306 and CdSe/ZnS QDs can lead to ROS accumulation, altered phagocytosis, and increased apoptosis in macrophages. 211 The excessive accumulation of ROS generated by QDs which can mediate not only the induction of apoptosis but also other forms of ROS-mediated cell death can also be triggered, such as autophagy, 307–312 inflammation, 201,203,216,313–316 pyroptosis, 203,214,316 necrosis, 317–319 and ferroptosis. 320…”

The State of the Art of Theranostic Nanomaterials for Lung, Breast, and Prostate Cancers

“…The core materials are generally composed of CdSe, CdTe, CdS, ZnS, ZnSe, PbS and PbSe, InP, and InGaP, with a core-shell structure of 1 to 10 nm in diameter [ 15 ]. The inorganic coating with ZnS and CdS on the particle’s surface improves the photoluminescent quantum efficiency and protects the nucleus from oxidation in biological environments, as they are formed from inorganic elements whose cytotoxicity can be significant even at low concentrations [ 16 , 17 ].…”

Modification of fluorescent nanocrystals with 6-thioguanine: monitoring of drug delivery

“…No signs of precipitation were observed for at least 4 weeks of storage. To obtain MAA-capped CdSe x S 1-x /ZnS QDs, the procedure described in our previous report was exploited (Kalinowska et al 2018).…”

“…The obtained mixture was sonicated for 20 min to finalize acidic digestion of nanocrystals. Cadmium ion was determined by means of anodic stripping voltammetry according to methodology described in our previous reports (Kalinowska et al 2018). The method of multiple standard addition (min.…”