Enhancing developmental rate and quality of mouse single blastomeres into blastocysts using a microplatform

The present work reports the beneficial effects of using a microplatform on the development of mouse single blastomeres (SBs) to the blastocyst stage. Development of blastocysts from SBs separated from two- and four-cell stage embryos (two- and four-cell SBs) can provide a valuable supply both for couples who use fertility-assisted techniques and farm animals. As a step forward, we introduce three chips that provide the possibility of culturing SBs separately, in groups, and in the vicinity of the intact embryo (co-culture), while each well of the chips is assigned to an isolated SB. Two- and four-cell SBs co-cultured with intact embryos showed 97.1% and 76.6% developmental rates and up to 34.1% and 49.1% growth relative to the microdroplet method (control). We examined the quality of developed blastocysts by assessing the total cell number, the number of inner cell mass (ICM) according to the octamer-binding transcription factor 4 marker (OCT4), and trophectoderm (TE). Co-culture of SBs with an intact embryo in a chip with nanoscale culture medium volume also increased the cell population of the developed embryo. The ICM:TE ratio, which is the most important blastocyst quality parameter, also indicated that developed two-cell SBs have a higher degree of similarity to intact embryos despite fewer numbers of total cells.