Embryo formation from low sperm concentration by using dielectrophoretic force

Abstract

A biochip system imitates the oviduct of mammals with a microfluidic channel to achieve fertilization in vitro of imprinting-control-region (ICR) mice. We apply a method to manipulate and to position the oocyte and the sperm of ICR mice at the same time in our microfluidic channel with a positive dielectrophoretic (DEP) force. The positive dielectrophoretic response of the oocyte and sperm was exhibited under applied bias conditions AC 10 Vpp waveform, 1 MHz, 10 min. With this method, the concentration of sperm in the vicinity of the oocyte was increased and enhanced the probability of natural fertilization. We used commercial numerical software (CFDRC-ACE+) to simulate the square of the electric field and analyzed the location at which the oocyte and sperm are trapped. The microfluidic devices were designed and fabricated with poly(dimethylsiloxane). The results of our experiments indicate that a positive DEP served to drive the position of the oocyte and the sperm to natural fertilization (average rate of fertilization 51.58%) in our microchannel structures at insemination concentration 1.5 × 10(6) sperm ml(-1). Embryos were cultured to two cells after 24 h and four cells after 48 h.

Improving ICSI: A review from the spermatozoon perspective

“…On one hand, a well-trained embryologist in an adequately equipped laboratory may not require usage of any of these techniques in order to ensure satisfactory results with ICSI. On the other hand, exemption for cases with previous failed fertilization [Huang et al 2015a;Huang et al 2015b;Nadalini et al 2014;Romany et al 2014] may be required. The field of IVF and the practice of ICSI would certainly benefit from standardization, at several levels, rather than relying on highly promising techniques 'of the future' that increase the cost and adds further levels of complexity to the already invasive nature of the technique.…”

Advances in Microfluidics‐Based Assisted Reproductive Technology: From Sperm Sorter to Reproductive System‐on‐a‐Chip

“…Various microfluidic mechanisms used for insemination. A) Microwell arrays for oocyte trapping; B) filter‐like microchannel design to confine the oocyte fabricated from cyclic olefin polymer (COP); C) egg cup oocyte trapping with on‐chip imaging of insemination process; D) oocyte trapping with positive DEP . The figures were redrawn with some changes from refs.…”

“…However, it is worth mentioning that none of the reported microfluidic IVF platforms had been equipped with a proper oocyte sorting mechanism to actively select high‐quality and healthy oocytes for fertilization. Figure 5 summarizes different microfluidic mechanisms used in the literature to inseminate oocyte, i.e., microwell arrays, filter‐like microchannel, egg‐cup structure, and noncontact positive DEP trapping . Han et al devised a two‐layer microfluidic device for oocyte trapping and subsequent insemination and embryo culture (Figure A).…”

“…In such device, sperms can inseminate the entrapped oocyte from the bottom microchannel, and an optical microscope can take the images of the insemination process. Huang et al devised a noncontact microfluidic platform to trap oocytes (Figure D). The authors showed the response of sperms and oocytes to positive DEP under the applied bias conditions.…”

Microfluidic assessment of swimming media for motility-based sperm selection

“…10,11 Recently, microfluidics emerged as a high-throughput, automated, and sensitive platform for studying gamete function, 12,13 sperm selection, 14,15 and embryo development. 16,17 Several factors urge the application of microfluidics for ARTs including: (1) providing a geometrically confined environment that closely mimics the in vivo environment, 18 (2) possibility of highly multiplexed sample analysis, 14 (3) operating with small sample volumes relevant for hypospermia (i.e. low semen volume), 19 and (4) possibility of on-chip visualization due to transparency of the microfluidic devices.…”