On-chip oocyte cumulus removal using vibration-induced flow

Abstract

Cumulus removal (CR), the removal of the small protective granulosa cells that surround an oocyte, is a crucial step in assisted reproductive technologies (ART). Traditional CR methods rely on vortexing or manual pipetting, which can result in inconsistencies and variability. Here, we present an open-surface platform featuring pillars that actively separates differently sized particles and removes cumulus cells from oocytes through vibration-induced flow (VIF). The platform removed 99% of small particles from the loading chamber by generating a local flow through the pillar array and separating smaller particles from larger particles. The platform was then used to remove cumulus cells from oocytes. CR under different actuation powers, time exposures, and hyaluronidase (HA) concentrations was optimized. The CR of up to 23 oocytes was accomplished simultaneously without any oocyte loss. Finally, mouse cumulus-oocyte complexes (COCs) were inseminated and CR was performed using both manual pipetting (control) and VIF. No statistical difference was observed in the fertilization and blastocyst rates, which were 90.7%, and 50.0% using manual pipetting, respectively, and 93.1% and 43.1% using VIF respectively. This platform automates CR process and reduces the technical manual labor involved in ART, paving the way for standardization and consistency within ART protocols.