Cytotoxicity & Viability Assays


Our cytotoxicity and viability assays provide quantitative evaluation of compound-induced cell damage and survival—critical for distinguishing therapeutic efficacy from toxicity in drug discovery. These assays are optimized for high reproducibility and throughput, supporting early-stage compound screening, lead optimization, and preclinical safety assessment for flavivirus inhibitors and other therapeutic candidates.

Key Assay Technologies

MTT & MTS Assays

Colorimetric detection of mitochondrial dehydrogenase activity to measure viable cell number. Optimized for 96/384-well formats with reduced background interference from small molecules.

Readout: Absorbance (570 nm)

LDH Release Assay

Quantification of lactate dehydrogenase (LDH) leakage from damaged cells to assess membrane integrity. Validated for both adherent and suspension cell lines.

Readout: Absorbance (490 nm)

Live/Dead Staining

Fluorescence-based dual staining (calcein-AM for live cells, ethidium homodimer for dead cells) for direct visualization and quantification of cell viability via high-content imaging.

Readout: Fluorescence (Ex485/Em535, Ex528/Em617)

ATP Luminescence Assay

Ultra-sensitive detection of intracellular ATP (a marker of metabolically active cells) using luciferase-based luminescence. Ideal for low-cell-number samples and high-throughput screening.

Readout: Luminescence (Relative Light Units)

Assay Performance Specifications

96/384 Well Plate Formats
24-72 Incubation Hours
<5% CV (Intra-Assay)
<10% CV (Inter-Assay)
100-10k Cells/Well (Optimal)

Assay Design & Validation

  • Dose-Response Profiling: Automated generation of IC50 values for compound cytotoxicity, with 8-10 concentration points per compound
  • Cell Line Specificity: Assays optimized for relevant cell models (e.g., Vero cells for flavivirus studies, HeLa/SH-SY5Y for human cell toxicity)
  • Positive Controls: Standardized controls (e.g., staurosporine, Triton X-100) to ensure assay robustness across batches
  • Media Interference Testing: Evaluation of compound solubility and media interaction to eliminate false-positive/negative results
  • Reproducibility Testing: Validation across multiple operators and equipment to meet GLP-compliant standards for preclinical studies

Research Applications

Early-Stage Compound Screening

High-throughput assessment of cytotoxicity for large compound libraries to prioritize candidates with low toxicity profiles.

Therapeutic Index Calculation

Comparison of antiviral/therapeutic efficacy (EC50) vs. cytotoxicity (CC50) to determine therapeutic index (TI = CC50/EC50) for lead compounds.

Mechanism of Toxicity Studies

Combination with apoptosis/necrosis markers (e.g., caspase activation, reactive oxygen species) to distinguish cell death mechanisms induced by compounds.

In Vitro Safety Assessment

Evaluation of compound toxicity in primary human cells (e.g., hepatocytes, neurons) to predict in vivo safety profiles.

← Back to Cellular Assays