Development of a microfluidic system structured on a modified polydimethylsiloxane device for the selection of bovine epididymal spermatozoa

Abstract

Microfluidic systems are on the rise in several studies that evaluate reproductive cells. However, the material used for manufacturing can still be considered relatively expensive. The objective of this study was to develop a new microfluidic device, using a modified polydimethylsiloxane ((PDMS) Silpuran®), test its viability and carry out a selection of bovine sperm. Sperm was collected from epididymis (n = 10) and evaluated at different incubation times (60 min, 120 min, 180 min) to assess polydimethylsiloxane toxicity, where a tube was used as a control and the microfluidic device as treatment. An additional ten epididymis were used for the sperm selection test, which utilized four types of solutions: in vitro maturation medium (IVM) with and without oocyte, progesterone and saline solution (SS). The Percoll gradient was used as a control and the microfluidic device as treatment. The kinetic parameters of sperm were evaluated using the computer-assisted semen analysis (CASA). Morphology was performed with Bengal Rose, the integrity, and viability of the sperm using the hypoosmotic test and fluorescent microscopy probes, respectively. Mann-Whitney test was used in the first experiment, Kruskall-Wallis variance analysis tests with post hoc and Student-Newman-Keuls used in the second experiment. Regarding the non-toxic effects, most motility parameters demonstrated the superiority of the microfluidic device compared to the control. In the second experiment, the sperm showed equivalence between the microfluidic device and the Percoll gradient Silpuran® PDMS was not toxic to the cells and can be efficient for selecting bovine sperm, achieving better results in a medium for IVM with or without oocytes.