title: Release and lubricating properties of amniotic surfactants and the very hydrophobic surfaces of the amnion, chorion, and their interface.
abstract: Surface hydrophobicity of 17 fresh human chorioamniotic membranes was measured as the contact angle (theta) subtended when a drop of saline is placed upon any non-wettable surface. The contact angle averaged 75.5 +/- 4.2 degrees and 76.8 +/- 5.6 degrees on the epithelial surfaces of the amnion and chorion, respectively. The interface proved to be particularly hydrophobic, averaging 108.2 +/- 8.7 degrees on the amnionic side and 121.7 +/- 4.2 degrees on the chorionic side, especially when compared with 108 degrees for Teflon. High surface hydrophobicity implies good boundary (solid-to-solid) lubrication, good release from neighboring tissues, and water repellency, which is a possible factor enabling the chorioamniotic membrane to retain amniotic fluid. Good release (68 to 71%) and boundary lubrication (coefficient of kinetic friction = 0.24 +/- 0.072) were obtained from oriented monolayers of the phospholipid extracted from samples of human amniotic fluid obtained from term patients by amniocentesis. These results support the concept that the amnionic and chorionic membrane surfaces exhibit good release and boundary lubrication probably imparted by adsorbed surfactant.
mesh_terms: D000650:Amnion / Q000187:drug effects / Q000502:physiology*; D002823:Chorion / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D008153:Lubrication; D010743:Phospholipids / Q000494:pharmacology; D011247:Pregnancy; D013499:Surface Properties
chemical_list: D010743:Phospholipids