DESIGN OF A NOVEL APPARATUS TO STUDY NITRIC-OXIDE (NO) INHIBITION OF PLATELET-ADHESION

Nitric oxide (NO) is a simple biological molecule which inhibits adhes ion and aggregation of platelets. A novel NO delivery device has been developed to quantitatively study the effects of NO concentration and flux on the adhesion of platelets to a surface. The slit-flow device i s lined with a protein-coated membrane through which NO gas permeates into a perfusing platelet suspension. A model predicting spatial NO co ncentrations and fluxes within the how slit was validated. At a wall s hear rate of 250 s(-1), platelet adhesion was inhibited 87% relative t o controls for exposures as low as 0.1 ppm NO. Corresponding model pre dictions of the aqueous NO concentration and fluxes at the surface wer e 0.15 nM, and between 0.5 and 1.1 nanomoles cm(-2) s(-1), respectivel y. Endothelial cells, which release NO to inhibit platelet adhesion in vivo, generate NO at an estimated flux similar to the above values. A t a NO exposure of 0.02 ppm, platelet inhibition was only 10%. The del ivery device is useful for other studies in which a knowledge of the s patial NO fluxes or concentrations is desired. Knowledge of these flux es or concentrations is beneficial towards the design of biomaterials incorporating NO to inhibit platelet adhesion. (C) 1998 Biomedical Eng ineering Society. [S0090-6964(98)00506-2].