Sperm processing for advanced reproductive technologies: Where are we today?

Assisted reproductive technologies (ARTs) utilize sperm sorting methods to select viable sperm from the semen samples. Conventional sperm sorting techniques in current use are density gradient centrifugation, direct swim-up, and conventional swim-up. These methods use multiple centrifugation steps, which have been shown to generate reactive oxygen species (ROS) that decrease DNA integrity and damage sperm. Newer technologies, such as microfluidics, electrophoresis, motile sperm organelle morphology examination (MSOME), and birefringence eliminate the centrifugation steps and can improve the selection of sperm with higher DNA integrity, normal morphology, and motility as well as improved artificial insemination outcomes. In this review, we discuss some recent research in centrifugation and non-centrifugation based techniques and their effect on sperm quality and ART outcomes.