Hyaluronan is a molecule that is found around eggs in the human body. Mature, viable sperm bind to hyaluronan molecules and break them down on their journey to meet and fertilise an egg.

Physiological intracytoplasmic sperm injection (pICSI) is a type of ICSI (Intracytoplasmic Sperm Injection (ICSI) – Oasis Fertility Centre) insemination in which a solution containing hyaluronan is added to the sperm. Only mature sperm with better DNA quality bind to the hyaluronan. These sperm are easily identifiable as they cease swimming forward, instead beating their tails but remaining stationary. Embryologists are then able to select sperm for ICSI injection from the affected group of sperm.

It is thought that the use of sperm that has demonstrated hyaluronan binding may improve clinical outcomes in some patients.