Oocyte all-surfaces' imaging method using micro-scale rotational flow.

In this work, the authors report an all-surfaces' image capturing method of a single oocyte that uses micro-scale rotational flow. Here, the authors used this method gently and indirectly rotated the single pronuclear zygotes (physical properties are similar to those of oocytes) to obtain images of all its surfaces in 0.33 s. The necessary equipment to realise this method consists of only a syringe pump and a microfluidic chip with a single 40 µm diameter orifice. Assessment of viability and quality of oocytes or embryos during the process of intra cytoplasmic sperm injection) and in vitro fertilisation is important for good embryo development. At present, manual morphological evaluation is the most common method to assess viability and quality of oocytes. Usually, during the manual morphological evaluation, the operator is required to manipulate the oocyte to achieve its full surface image. However, manipulation is difficult, even for an experienced operator. Conventional methods using the principles of mechanics, electronics, or magnetism require a complex system. Conventional methods using principles of fluids or optics also have limitations about target size and transparency. Here, a method is proposed and proved of using rotational flow to gently capture and rotate a mouse zygote without using a complex control system and achieved its full surface image in 0.33 s. The method offers a new tool for morphological evaluation of assessment of viability and quality of oocytes. [ABSTRACT FROM AUTHOR]