Density gradient separation of sperm for artificial insemination.

Human spermatozoa for clinical procedures such as IUI or IVF, or for diagnostic or research studies of sperm fertilizing ability, must be separated from the seminal plasma environment not only as soon as possible after ejaculation but also as efficiently as possible, minimizing seminal plasma and bacterial carryover. Furthermore, in addition to technical simplicity and robustness, a sperm preparation method needs to select not just the more motile and morphologically normal spermatozoa but also those spermatozoa with reduced DNA damage. Currently the most effective and efficient technique for this is density gradient centrifugation, which has been extensively validated through research and clinical application. An optimized protocol based on silane-coated colloidal silica products is provided.