Abstract
In order to find an inhibitory mechanism of platelet activation on HEMA-St block copolymer surfaces with an alternate lamella structure, the platelet response which pre incubated at 37°C for one hour to the block copolymer surfaces was analyzed at the ultrastructural level by scanning (SEM) and transmission electron microscopy (TEM). Especially, TEM data of platelets after contact with the block copolymer surfaces were quantified by image analyzer. PSt, HEMA-St random copolymer surfaces were prepared as polymers for comparison. The interaction between the platelets and the polymer surfaces (diameter of polymer beads, 150μm) was employed by experimental equipment under 37°C conditions based on the microsphere column method (column length, 10cm; column inner diameter, 3mm). The flow rate was carried out at 0.1ml/min for 15 minutes. The platelets after contact with the polymer surfaces were analyzed by TEM. And then, a number of storage granules per 1μm2 in unstimulated platelets and platelets after contact with the block copolymer surfaces were quantified by image analyzer. The platelets adhered to the polymer surfaces for an incubation period of 3 hours were analyzed by SEM and TEM. As a result, it was found that the block copolymer surfaces inhibit remarkably platelet activation in any case of enhancing platelet response activity by means of preincubating platelets at 37°C for one hour compared to that of PSt and the random copolymer surfaces. On the TEM image analysis of the platlets, the number of platelet storage granules on the block copolymer surfaces didn't indicate any significant difference when compared to that of unstimulated platelets. It was suggested that the block copolymer surfaces have an active inhibition effect on platelet activation.
