Toxicity assays in nanodrops combining bioassay and morphometric endpoints

Area of Science:

• Toxicology
• Cell Biology
• Biotechnology

Background:

• Chemical hazard management and drug ADMETOX prediction require advanced in vitro toxicity assays.
• Reducing animal testing necessitates high-throughput and relevant in vitro methods.

Purpose of the Study:

• To develop and validate a novel in vitro toxicity testing method.
• To assess chemical hazards within the REACH policy framework.

Main Methods:

• Utilized a genetically engineered, stress-sensitive hepatic cell line (HepG2) in a nanodrop Cell-on-Chip format.
• Monitored Enhanced-Green Fluorescent Protein expression controlled by Heat Shock Protein promoters upon exposure to toxicants.
• Performed multiparametric analyses using image-based screening for individual cell identification.

Main Results:

• Observed chemical-specific responses in HepG2 cells, characterized by distinct dynamics and amplitude.
• Determined IC50 values for Cadmium Chloride (CdCl2) and Sodium Arsenate (NaAsO2), consistent with published data.
• Demonstrated superior sensitivity of stress promoter activation and cell morphology parameters over cell mortality.

Conclusions:

• Pre/sub-lethal cell stress indicators provide significant insights into toxicant effects.
• This represents a first-generation high-throughput, high-content assay for in vitro chemical hazard assessment.
• The developed assay is suitable for compliance with REACH policy requirements.