Cytotoxicity and transcriptome changes triggered by CuInS₂/ZnS quantum dots in human glial cells

Area of Science:

• Nanotechnology
• Materials Science
• Toxicology

Background:

• Cadmium-free quantum dots (QDs) like CuInS2/ZnS offer potential applications but require thorough biological safety assessment.
• Understanding the in vitro toxicity of CuInS2/ZnS QDs is crucial for their safe development and application.

Purpose of the Study:

• To investigate the in vitro toxicity of CuInS2/ZnS quantum dots on the U87 human glioma cell line.
• To evaluate the cellular uptake, impact on cell viability, and gene expression changes induced by CuInS2/ZnS QDs.

Main Methods:

• U87 cells were exposed to varying concentrations of CuInS2/ZnS QDs.
• Cellular uptake was assessed using fluorescence imaging and flow cytometry.
• Cell viability was determined via MTT assay.
• Gene expression profiles were analyzed using transcriptome sequencing.

Main Results:

• CuInS2/ZnS QDs were effectively internalized by U87 cells, primarily localizing in the cytoplasm, with over 90% uptake at 25 μg/mL.
• Cell viability showed a transient increase at 24 hours for higher concentrations (50 and 100 μg/mL) but no significant reduction at later time points (48 and 72 hours).
• Transcriptome analysis revealed significant alterations in gene expression, with 220 genes upregulated and 1515 downregulated, impacting functions related to nucleosomes, chromosome-DNA binding, and chromosome assembly.

Conclusions:

• CuInS2/ZnS quantum dots are internalized by U87 cells and do not decrease cell viability in vitro.
• Significant modulation of the gene expression profile occurs following exposure to CuInS2/ZnS QDs.
• These findings highlight the importance of understanding the genotoxic potential of CuInS2/ZnS QDs for their responsible application.