Transparent Alumina Ceramics-Based Microfluidic Chip Enables on-Chip Cryopreservation for Mouse Oocyte

Oocyte cryopreservation plays a crucial role in safeguarding female fertility in clinical practice. However, commonly used cryopreservation methods involving tedious and time-consuming procedures, as well as uncontrolled variability between operators, which can easily lead to cell damage. Here, a novel method for cryopreserving oocytes using a transparent alumina ceramics-based microfluidic chip is developed, which provides an integrated platform for cryoprotectants (CPAs) loading/unloading, as well as freeze-thaw process and storage. The cryopreservation protocol is optimized to significantly simplify the overall process, reduce CPA osmotic damage, and achieve high-performance oocyte cryopreservation. The survival rate of oocyte cryopreserved with this method reached 86.23%. In comparison to conventional method, the recovered oocytes exhibit structural stability, functional integrity, genetic normality and higher developmental capacity. The study offers a low-cost, easy-to-operate, high-performance, on-chip semi-automatic cryopreservation technique for oocytes, which is of great significance for standardizing and automating the cryopreservation of female fertility, and has important potential for translational applications.