Open-source 3D-printed microscope with semiautomated liquid crystal polarizer setups: a new opportunity for detecting small phase retards in oocyte meiotic spindles

A microscope design was developed using 3D printing and liquid crystals to achieve variable polarization configurations and semi-automatic processes without the need for mechanical movement of polarizers and retarders. The device includes a polariscope composed of electronically controlled liquid crystals and a compliant mechanism for precise micrometric movements. Stepper motors and software control these movements, and the process of acquiring images requires connecting a sensor to a Raspberry Pi. The microscope's lens and extension tube assembly magnify the image 600 times. The study compares two polarization techniques: Stokes and ellipsometric polarization. Additionally, it analyzes crystals and meiotic spindles of maturing porcine oocytes. The ellipsometric technique is more effective in detecting low retards, as indicated by the results. This prototype has the potential to reduce the cost of in vitro fertilization in assisted reproduction laboratories, with a focus on animals of high genetic value.