A novel microfluidic device for selecting human sperm to increase the proportion of morphologically normal, motile sperm with uncompromised DNA integrity

Abstract

Objective: We assessed a microfluidic method of sperm selection. Methods: Sperm was collected from 33 infertile, but otherwise healthy donors. We established a microfluidic device consisting of a 250 μm diameter microchannel of 3 cm in length, to mimic the oviduct. Human tubal fluid was pumped through the tubule at 500 μm s⁻¹, and 5 ml sperm was added. The movement of sperm was observed for 30 min using a Live Cell Imaging System. Sperm motility was assessed by using a Computer-aided Sperm Analysis System, morphological parameters were observed by conventional light microscopy and transmission electron microscopy, and DNA integrity was measured by comet assay. We compared the fitness of sperm selected using a microfluidic device with pre-selection sperm and sperm selected by the density gradient and swim-up method. Results: Microfluidic selection improved motility parameters of all 33 samples. Sperm selected by using the microfluidic device had higher rates of average ratio of sperm fast swimming forward average sperm activity ratio, value derivation for the curvilinear, value derivation for straight-line velocities, value derivation for average path, amplitude of lateral head displacement, amplitude of cross-frequency, progression ratios of linearity, progression ratios of wobble, progression ratios of straightness, and lower rates of deformity than sperm selected using conventional methods (p < 0.05). Furthermore, the DNA integrity of sperm selection by our device was better maintained than that selected by traditional methods (p < 0.05). Conclusion: This method can not only minimize damage to the sperm structure, but also increase the effectiveness of selection.