Ecotoxicology currently lacks automated, user-friendly, and cost-effective bioanalytical platforms, as it still relies largely on conventional aquatic toxicity testing, which is time-consuming, labor-intensive, and inherently low throughput. In this study, we optimized a microfluidic Lab-on-a-Chip (LOC) platform to perform automated Fish Embryo Toxicity (FET) bioassays using marine fish embryos of Sparus aurata. The device enables loading and immobilization of large numbers of embryos and, when coupled with a peristaltic pump, supports continuous microperfusion of test chemicals in either closed- or open-loop configurations, while also allowing embryo recovery for downstream analyses. To validate the method and assess its applicability for marine FET assays, we tested copper and zinc as model inorganic contaminants. Chip-based assays and conventional static exposures data (adapted from OECD Test Guideline 236) were compared by fitting survival data to dose–response curves to derive 48 h percent lethal concentrations (LCx). For copper, LC50 values were similar across both systems, with no significant difference between dose–response relationships. In contrast, zinc elicited system-dependent effects: Embryos exhibited higher tolerance in chip-based assays, with a statistically significant divergence from static exposures. Time-resolved toxicokinetic–toxicodynamic modelling (GUTS framework) further revealed distinct survival dynamics: Copper caused abrupt mortality with moderate model performance (r2 ≈ 0.6), whereas zinc induced gradual effects that were well captured (r2 = 0.96). This study provides the first demonstration of an optimized chip-based platform for automated FET bioassays in a marine fish species, Sparus aurata. Our findings highlight the potential of LOC technologies, particularly when combined with mechanistic modelling, to advance high-throughput aquatic ecotoxicology.
Campana et al. (Sun,) studied this question.