Surface endotoxin contamination and hemocompatibility evaluation of materials
Maitz M.F., Teichmann J., Sperling C., Werner C
J Biomed Mater Res B Appl Biomater (2008). DOI:10.1002/jbm.b.31247 (in press)
To evaluate the blood compatibility of new materials a clear distinction between properties of the materials and effects due to surface contamination by adsorbed endotoxins is essential. The present study compares direct contact approaches and elution methods with water, organic solvents, non-ionic and zwitter-ionic
detergents for determination of surface-adsorbed endotoxin by the limulus amoebocyte lysate (LAL) test and determines the blood compatibility of various surfaces with controlled endotoxin contamination in vitro. The LAL test in direct contact with an endotoxin-contaminated surface was concluded to be not practicable for most devices and its sensitivity showed a high dependence on surface characteristics. Among the elution methods, 0.2% Tween-20 showed most stable elution characteristics and
appears therefore preferable. Biological reactions at in vitro blood exposure were found to be only minimally influenced by adsorbed endotoxin during the time window of two hours, allowing for a straightforward discrimination between materials and endotoxin dependent reactions.