Evaluation of a Novel Fluorescent Marker for Continuous Live Imaging of Preimplantation Embryos

This study evaluates ChromaLIVETM, a multichromatic, mix-and-read fluorescent marker developed for continuous live-cell imaging, in the context of embryology. The aim was to evaluate whether this marker is compatible with dynamic embryonic development up to the blastocyst stage, with minimal impact on embryo viability, integrity, or normal growth of mouse embryos at the 2-cell stage that were cultured to the blastocyst stage under time-lapse imaging conditions, either in the presence or absence of ChromaLIVETM. Results showed comparable blastocyst formation rates between ChromaLiveTM and the control group, as well as similar proportions of high-quality blastocysts. Although minor but statistically significant delays were noted in two kinetics events (t3 and tSB), other developmental timings remained unaffected. Time-lapse confocal fluorescence imaging demonstrated that ChromaLIVETM dye provided stable, bright, high-resolution 3D visualizations of cellular compartments including membranes, cytoplasm and embryonic structures such as trophectoderm, inner cell mass and blastocoel throughout development. Finally, transcriptomic analyses revealed a limited set of gene-expression differences between stained and unstained embryos; although these included developmental and metabolic pathways, embryos developed to the blastocyst stage comparably to controls.