A simple zeta method for sperm selection based on membrane charge

Objective: The objectives were: [1] to develop a simple zeta potential method for sperm isolation; and [2] to analyze the sperm maturity, morphology, kinematic, and DNA parameters. Design: The phenomenon of sticky sperm adhering to slide surfaces was adapted for collecting charged sperm. Setting: Clinical and academic research environment. Patient(s): Discarded colloid-washed sperm from routine laboratory testing (n = 8). Intervention(s): Sperm were centrifuged in serum-free medium and collected for analyses. Main Outcome Measure(s): Kinematic parameters, DNA integrity, and maturity. Result(s): The percentages of mature (73.0% ± 0.5% vs. control 63.5% ± 0.5% SEM) and DNA intact sperm (85.0% ± 0.3% vs. 69.5% ± 0.5%) increased in the male factor subgroup. Strict normal morphology (19.3% ± 0.1% vs. 10.0% ± 0.1%), hyperactivation (7.0% ± 0.1% vs. 3.6% ± 0.1%), and progressive motility (29.1% ± 0.1% vs. 19.9% ± 0.1%) increased by twofold. Conclusion(s): The zeta method improved sperm parameters associated with increased fertilization and pregnancy after assisted reproduction procedures. Manipulation from the attaching-detaching process stimulated sperm metabolism without causing premature acrosome reactions. Total motility was unchanged suggesting a lack of association between total motility and zeta potential.