In Vitro Fertilization on a Single-Oocyte Positioning System Integrated with Motile Sperm Selection and Early Embryo Development

Abstract

In vitro fertilization (IVF) technology has been broadly applied to solve human infertility in recent years. However, the physical tools for IVF remain unchanged over several decades before microfluidic technology was introduced in this field. Here, we report a novel microdevice that integrates each step of IVF, including oocyte positioning, sperm screening, fertilization, medium replacement, and embryo culture. Oocytes can be singly positioned in a 4 × 4 array of octacolumn units. The four symmetrical straight channels, crossing at the oocyte positioning region, allowed efficient motile sperm selection and facilitated rapid medium replacement. The fertilization process and early embryonic development of the individual zygote was traced with microscopic recording and analyzed by in situ fluorescent staining. The murine sperm motility was increased from 60.8 ± 3.4% to 96.1 ± 1.9% through the screening channels. The embryo growth rate and blastocyst formation were similar between the routine Petri dish group and the microdevice group. The healthy blastocysts developed in the microdevice could be conveniently retrieved through a routine pipetting operation and used for further embryo transfer.

Paper-Based Quantification of Male Fertility Potential

“…In the context of fertility, traditional channel-based devices have been developed for sperm selection (18 -22 ), embryo development (23)(24)(25), and semen analysis (14, 26 -28 ). Recently, paper has emerged as a scalable diagnostic platform (29 -32 ).…”

Recent advances in microfluidic diagnostic and treatment systems for assisted reproductive technologies in developing countries

“…These microfluidic devices can be used by pipetting sample liquid without complex fluid manipulation systems, such as electric pumps and bulbs, leading to the advantages of simplicity and low cost. Since the 1990s, microfluidic devices for sperm counts and motility analyses have been investigated by Kricka et al [39], and microfluidic POC systems for semen diagnostics sorting motile sperms or on-chip IVF using LOC have been reported [40][41][42][43][44][45][46][47][48][49][50][51]. Moreover, in addition to motile sperm separation, fluid flow-and viscosity-associated chemotaxis and mechanotaxis of mammalian sperm were investigated using microfluidic channels [45].…”

Microfluidics for sperm research

“…Another microdevice has been presented to perform each step of IVF, including oocyte positioning, fertilization, embryo culture, and sperm screening ( Figure 2E) [42]. Oocytes were individually positioned in a 4Â4 matrix of cylindrical units located at the intersection of two perpendicular microchannels, which enabled effective motile sperm separation and fast suspension-medium replacement.…”

“…Scanning electron micrograph of the 4Â4 array of cylindrical units for single oocytes. Reproduced, with permission, from[42]. (F) An interfacial valve-based microfluidic chip for thermotactic evaluation of human sperm.…”