Cytotoxicity and immune response of CdSe/ZnS Quantum dots towards a murine macrophage cell line

Abstract

The quantum dots (QDs) community has raised great concerns about the exposure and possible cytotoxicity impact of QDs to biological systems since the majority of QDs are made from heavy metals such as cadmium and lead. It is well known that macrophage cells serve as the first line of immune defense against exogenous substances, but the toxicity of QDs on macrophages remains poorly understood to date and some reported literature even have shown inconsistent results. In this study, we aimed at investigating the cytotoxicity and immune response of CdSe/ZnS QDs in mouse macrophage cells. Our confocal images showed that CdSe/ZnS QDs were captured by macrophages and were located in the cytoplasmic region. The flow cytometry assay showed that the uptake efficiency of QDs within cells was as high as 90%. More importantly, the cells treated with QDs showed a decrease in the cell viability and an enhanced gene transcription of cytokines IL-6 and TNFa was observed, but no changes were detected in the mechanism of releasing cytokines IL-6 and TNFa in the cells. These results suggest that the treatment of CdSe/ZnS QDs is indeed affecting the cell viability of the macrophages but did not cause any obvious immune response changes in the cells.

Immunotoxicity assessment of CdSe/ZnS quantum dots in macrophages, lymphocytes and BALB/c mice

“…The influence of CdSe/ZnS QDs on macrophages was discovered to be non-time dependent. Such phenomena might be resulted from the competitive uptake process between the neutral red and QDs because CdSe/ZnS QDs was mainly captured by macrophages within 2 h [ 12 ], which resulted in decreased uptake of the neutral red. However, 2 h later, the QDs-treated macrophages were activated, and the uptake ability of them was elevated.…”

“…The day before experiment, RAW264.7 macrophages (5.0 × 10 5 /dish) were seeded in 3.5 cm dishes. Macrophages were left untreated or exposed to 1.25 and 2.5 nM CdSe/ZnS QDs for 24 or 48 h. Then the cells were fixed, stained with DAPI, and imaged according to the procedure published previously [ 12 ].…”

“…T lymphocytes, B lymphocytes and natural killer cells) are important immune cells which mediated the innate and adapted immunity of human body. Previously, we have reported that carboxyl-terminated CdSe/ZnS QDs inhibited the cell proliferation of macrophages and the data showed that CdSe/ZnS QDs treatments indeed affect the cell viability of the macrophages [ 12 ]. But the molecular mechanisms responsible for QDs-mediated cytotoxicity remain unknown.…”

Quantum dot encapsulation in virus-like particles with tuneable structural properties and low toxicity

“…Cellular uptake efficiency of nanoparticles depends largely on the nanoparticle surface chemistries 52,53 as well as the type and origin of the cells. 54,55 In order to study whether VLP encapsulation interfered with the cellular uptake efficiency, we compared the intracellular uorescence intensity levels of RAW cells incubated with T ¼ 1 and T ¼ 3 assemblies as well as with 'bare' QDs ( Fig.…”

Nanoparticles for Bioapplications: Study of the Cytotoxicity of Water Dispersible CdSe(S) and CdSe(S)/ZnO Quantum Dots

“…There are various methods to determine the toxicity of QDs in both in vivo and in vitro studies. In vivo studies may involve introducing QDs to microorganisms [25] or the use of animal models [26,27,28,29,30], whereas in vitro toxicity features the treatment of various cell types with QDs in order to investigate the cytotoxicity of nanocrystals in mammalian cell lines [31,32,33,34,35,36,37,38,39,40,41,42,43]. A common feature in all reports of cadmium-based QDs, including CdTe, CdSe, and CdS, is that Cd is a primary source of toxicity.…”