A New Microfluidic Concept for Successful in Vitro Culture of Mouse Embryos

Abstract

Innovative techniques for gene editing have enabled accurate animal models of human diseases to be established. In order for these methods to be successfully adopted in the scientific community, the optimization of procedures used for breeding genetically altered mice is required. Among these, the in vitro fertilization (IVF) procedure is still suboptimal and the culture methods do not guarantee the development of competent embryos. Critical aspects in traditional in vitro embryo culture protocols include the use of mineral oil and the stress induced by repetitive handling of the embryos. A novel microfluidic system was designed and fabricated in poly dimethyl siloxane (PDMS) to allow for efficient in vitro production of mouse embryos. Culture experiments conducted by completing the industry gold standard Mouse Embryo Assay excluded any harmful fluidic stress and plastic toxicity. The developmental competence of the embryos developed in the device was consistently confirmed by high blastocyst rate (>80%), hatching and outgrowth rate, and matched with analysis of energy substrate metabolism and expression of genes related to implantation potential. Metabolomics analyses of spent culture media allowed for biologically important metabolite changes to be observed throughout embryo development, and for identification of specific overrepresented metabolic pathways affected by the microfluidic environment. Moreover, mass spectrometry data identified plastic-related compounds released in medium, and confirmed leaching of low molecular weight species into the culture medium that might be associated to un-crosslinked PDMS. Finally, these data show the potential for the system to study preimplantation embryo development and to improve the embryo culture techniques used for human assisted conception.