Standard buffer solution used to prepare wash media for the sperm wash procedure and sperm processing should be pharmaceutical grade, sterile and cellculture-tested. Although sterilization and cell-culture testing can be performed in one’s own laboratory – and some large laboratories do so to save cost – it is easier for most IUI laboratories to purchase buffer solutions and media that are sterile and already cell-culture-tested.
- HUMAN TUBAL FLUID MEDIUM (HTF) During simple sperm washing technique human tubal fluid (HTF) media is used. HTF is available commercially or can be prepared as per formulation given by Quinn et al, 1985. The sperm washing technique with HTF media leads to high yield of spermatozoa from good quality semen sample for intra-uterine insemination (IUI). Human tubal fluid (HTF) media contains HEPES (4-(2-hydroxyethyl)- 1-piperazineethanesulfonic acid ) that act as a buffering agent by maintaining the physiological pH. The media is supplemented with human serum albumin (HSA), 5mg/ml.
- SINGLE DENSITY GRADIENT MEDIUM A single density gradient media consist of 80% (v/v) gradient that is composed of colloidal silica coated with silane that has property to separate sperms from other cell types and debris according to their density. The normal progressively motile spermatozoa will swim actively through the gradient material to form a soft pellet at the bottom of the tube.
- A simple two-step discontinuous double density gradient preparation method is most widely applied and typically consists of 45% (v/v) density top layer and 90% (v/v) density lower layer, 100% density gradient is also available commercially. Discontinuous density gradients provide the best selection of good quality spermatozoa from other cell types and debris. It’s easier to standardize swim-up technique as results are more consistent.