Enrichment of bovine X-sperm using microfluidic dielectrophoretic chip: A proof-of- concept study

Tuempong Wongtawan; Naruphorn Dararatana; Chommanart Thongkittidilok; Sudsaijai Kornmatitsuk; Bovornlak Oonkhanond

doi:10.1016/j.heliyon.2020.e05483

Enrichment of bovine X-sperm using microfluidic dielectrophoretic chip: A proof-of- concept study

Heliyon. 2020 Nov 11;6(11):e05483. doi: 10.1016/j.heliyon.2020.e05483. eCollection 2020 Nov.

Authors

Tuempong Wongtawan^{1

2

3}, Naruphorn Dararatana^{3

4}, Chommanart Thongkittidilok^{1

2}, Sudsaijai Kornmatitsuk^{3

5}, Bovornlak Oonkhanond⁴

Affiliations

¹ Akkhraratchakumari Veterinary College, Walailak University, Thai Buri Tha Sala, Nakhon Si Thammarat, 80160, Thailand.
² Centre for One Health, Walailak University, Thai Buri Tha Sala, Nakhon Si Thammarat, 80160, Thailand.
³ Laboratory of Veterinary Biomedicine, Mahidol University, Salaya, Puttamonthon, Nakhon Pathom, 73170, Thailand.
⁴ Department of Biomedical Engineering, Faculty of Engineer, Mahidol University, Salaya, Puttamonthon, Nakhon Pathom, 73170, Thailand.
⁵ Department of Clinical Science and Public Health, Faculty of Veterinary Science, Mahidol University, Salaya, Puttamonthon, Nakhon Pathom, 73170, Thailand.

Abstract

The microfluidic dielectrophoretic (MF-DEP) chip is a new, economical and readily-available technology that might be used to enrich X-sperm for increasing female offspring in dairy farms. In this study, we sought to develop an MF-DEP chip to enrich X bovine sperm. The MF-DEP chip was composed of an electrode attached to a glass slide and a microchannel made from polydimethylsiloxane. Sex-sorted sperm from flow cytometry were used to identify optimal electric field conditions while unsorted sperm were later tested for sorting efficiency. The results show that during dielectrophoresis some sperm attached to the electrode (called positive DEP; pDEP) whereas other moved away from the electrode (called negative DEP; nDEP). X and Y-sperm responded to dielectrophoresis differently depending on various factors such as buffers, voltages, and frequencies. We found that the condition 4 V 1 MHz significantly reduced (P < 0.05) the percentage of Y-sperm to nearly 30 and therefore enriched X-sperm. The sorting efficiency was dependent on buffer, bull, sorting cycle, flow rate, electrical voltage, and frequency. Notably, the best sorting buffer found in this experiment was the conducting buffer, but this buffer significantly reduced sperm viability and motility. Other sperm-friendly buffers, TRIS and mHTF, were also used, but could not enrich X-sperm. In conclusion, this is a proof of concept that the MF-DEP chip can be effectively used to enrich bovine X-sperm. However, more research must be performed particularly to find the best sorting buffer to effectively sex-sort sperm while providing high motility and sperm viability.

Keywords: Animal science; Bioengineering; Biomedical engineering; Chip; Dielectrophoresis; Microfluidics; Reproductive system; Sex-sorting; Sperm; Veterinary medicine.