Blood compatibility of a ferulic acid (FA)-eluting PHBHHx system for biodegradable magnesium stent application

Magnesium stent has shown potential application as a new biodegradable stent. However, the fast degradation of magnesium stent limited its clinic application. Recently, a biodegradable and drug-eluting coating system was designed to prevent magnesium from fast degradation by adding ferulic acid (FA) in poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) by a physical method. In vitro study has demonstrated that the FA-eluting system exhibited strong promotion to the endothelialization, which might be a choice for the stent application. In this paper, the hemolysis rate, the plasma recalcification time (PRT), the plasma prothrombin time (PT) and the kinetic clotting time of the FA-eluting films were investigated and the platelet adhesion was observed in order to assess the blood compatibility of the FA-eluting PHBHHx films in comparison with PHBHHx film. The results have shown that the addition of FA had no influence on the hemolysis, but prolonged PRT, PT and the clotting time and reduced the platelet adhesion and activation, displaying that the FA-eluting PHBHHx exhibited better blood compatibility than PHBHHx. In addition, the effect of alkali treatment on the blood compatibility of FA-eluting PHBHHx was also studied. It was indicated that alkali treatment had no effect on the hemolysis and the coagulation time, but enhanced slightly the platelet adhesion. All these demonstrated that FA-eluting PHBHHx film had good blood compatibility and might be a candidate surface coating for the biodegradable magnesium stent.