A microfluidic platform with cell-scale precise temperature control for simultaneous investigation of the osmotic responses of multiple oocytes.

The temperature-dependent oocyte membrane permeability plays a significant role in oocyte cryopreservation, such as optimizing the addition/removal of cryoprotective agents and the rate of cooling/rewarming. However, the systems for studying the temperature dependence of oocyte membrane permeability are either too complicated or unable to achieve wide-range precise temperature control. In addition, these systems cannot achieve the simultaneous observation of multiple oocytes. Here, we report a novel microfluidic platform that combines a precise local temperature heater/detector and a simple global water bath to achieve wide-range accurate temperature control without increasing the difficulty of fabrication, and it also realizes non-interfering, position-controllable and non-missing capture of multiple oocytes for parallel experiments to increase throughput. The permeability coefficients (Lp, Ps) of the mouse oocyte membrane exposed to cryoprotective agents (1.5 M EG and 1.5 M PG) at four temperatures (4, 15, 25 and 37 °C) are consistent with those reported in previous works, which proves the feasibility and practicality of the microfluidic platform in this study.