Per- and Polyfluoroalkyl Substances (PFAS) Cytotoxicity and Genotoxicity in HepG2 Human Hepatoma Cells

Abstract Per- and polyfluoroalkyl substances (PFASs) commonly occur as complex mixtures, yet the relationships among PFAS structure, cytotoxicity, and DNA strand-break responses remain incompletely resolved. We evaluated 11 PFASs selected to span environmentally prevalent and regulatory-relevant perfluorocarboxylic acids (PFCAs), perfluorosulfonic acids (PFSAs), and fluorotelomer sulfonates (FTSs) in HepG2 cells using MTT cell-viability and alkaline comet assays. Individual PFAS showed a wide range of cytotoxic potency after 24 h, with IC50 ranging from 5700 μM for perfluorobutanoic acid (PFBA) to 0.3 μM for 8:2 FTS. Cytotoxic potency followed the order 8:2 FTS > PFOS > PFNA > PFOA > PFHxS > 6:2 FTS > HFPO-DA > PFHxA > PFBS > 4:2 FTS > PFBA. A PFAS mixture test was conducted to investigate the effects of PFAS type and concentration. Short-chain PFAS pairs exhibited predominantly antagonistic interactions, whereas 4:2 FTS + 8:2 FTS showed the most consistent synergistic pattern. DNA strand-break responses did not parallel cytotoxic potency: PFOA produced the largest tail moment, whereas 8:2 FTS was the most cytotoxic PFAS. LC–MS/MS exposure verification quantified PFAS concentration in the medium and identified condition-dependent losses for PFOS and 8:2 FTS. These findings provide screening-level evidence that PFAS hazard ranking depends on both chemical structure and end point, while the high administered concentrations and in vitro exposure limitations preclude direct inference to environmental risk.