Biomaterials lubricated for minimum frictional resistance.

To improve the frictional characteristics of a biomaterial, the mechanical performance of a lubricated surface was studied. In vitro friction tests showed that the coefficient of dynamic friction of the lubricated surface was about 0.01 against rabbit bladder and the coefficient of static friction increased with the preload period. The efficacy of a lubricated cystoscope was evaluated by an in vivo test simulating cystoscope operation. The maximal and the total resistance force on the cystoscope model were found to decrease with the surface lubrication. Histological study revealed that urethral damage caused by rubbing with the cystoscope model was reduced by this lubrication technique. Presumably, prolonged retention of water on the lubricated surface region prevented tissue adhesion to the foreign material.