Microfluidics as an emerging paradigm for assisted reproductive technology: A sperm separation perspective

Millions of people are subject to infertility worldwide and one in every six people, regardless of gender, experiences infertility at some period in their life, according to the World Health Organization. Assisted reproductive technologies are defined as a set of procedures that can address the infertility issue among couples, culminating in the alleviation of the condition. However, the costly conventional procedures of assisted reproduction and the inherent vagaries of the processes involved represent a setback for its successful implementation. Microfluidics, an emerging tool for processing low-volume samples, have recently started to play a role in infertility diagnosis and treatment. Given its host of benefits, including manipulating cells at the microscale, repeatability, automation, and superior biocompatibility, microfluidics have been adopted for various procedures in assisted reproduction, ranging from sperm sorting and analysis to more advanced processes such as IVF-on-a-chip. In this review, we try to adopt a more holistic approach and cover different uses of microfluidics for a variety of applications, specifically aimed at sperm separation and analysis. We present various sperm separation microfluidic techniques, categorized as natural and non-natural methods. A few of the recent developments in on-chip fertilization are also discussed.

X and Y chromosome-bearing spermatozoa are equally able to uptake and internalize exogenous DNA by sperm-mediated gene transfer in swine

Since proteomic differences between male X/Y chromosome-bearing gametes have recently been described, a question has been raised: could these differences be responsible for different behavior between X and Y chromosome-bearing spermatozoa during the binding and internalization of exogenous DNA in the swine species? In order to investigate this hypothesis, our group studied the process of the uptake and internalization of exogenous DNA in X and Y chromosome-bearing sperm sub-populations. No significant differences were found between sperm types in both the uptake and internalization of exogenous DNA. The quantity of internalized exogenous DNA was significantly lower than that of the uptaken DNA. In conclusion, our results showed that X and Y chromosomes-bearing spermatozoa have the same binding capacity and internalization of DNA, and the proteomic differences between them do not seem to interfere with these complex processes.