Automated Lab-on-a-Chip Technology for Fish Embryo Toxicity Tests Performed under Continuous Microperfusion (μFET)

Feng Zhu, Adriana Wigh, Timo Friedrich, Alain Devaux, Sylvie Bony, Dayanthi Nugegoda, Jan Kaslin, Donald Wlodkowic

The fish embryo toxicity (FET) biotest has gained popularity as one of the alternative approaches to acute fish toxicity tests in chemical hazard and risk assessment. Despite the importance and common acceptance of FET, it is still performed in static multi-well plates and requires laborious and time-consuming manual manipulation of specimens and solutions. This work describes design and validation of a microfluidic Lab-on-a-Chip technology for automation of the zebrafish embryo toxicity test common in aquatic ecotoxicology. The innovative device supports rapid loading and immobilization of large numbers of zebrafish embryos suspended in a continuous microfluidic perfusion as a means of toxicant delivery. Furthermore we also present development of a customized mechatronic automation interface that includes a high-resolution USB microscope, LED cold light illumination and miniaturized 3D printed pumping manifolds that were integrated to enable time-resolved in situ analysis of developing fish embryos. To investigate the applicability of the microfluidic FET (μFET) in toxicity testing, copper sulfate, phenol, ethanol, caffeine and dimethyl sulfoxide were tested as model chemical stressors. Results obtained on a chip-based system were compared with the conventional static FET protocols. This work provides evidence that FET analysis performed under microperfusion opens a brand new alternative for inexpensive automation in aquatic ecotoxicology.