In vivo biological safety evaluation of an iron-based bioresorbable drug-eluting stent.

Bioresorbable stents (BRS) are investigated and designed to revascularize occluded arteries. The iron-based bioresorbable stent is a promising device in interventional therapies, although it's corrosion and bioresorption rate remain challenging. In this work, we introduced a novel nitrided iron coronary stent (IBS) with enhanced degradation rate compared with pure iron stent. To evaluate the biosafety of this device, a sub-chronic systemic toxicity study was conducted and a stainless steel stent (Supporter™) served as a control. Here, the bioresorbable stent was first evaluated in rat abdominal aortic implantation model. When subjected to exaggerated exposure dose, no clinical signs of toxicity or mortality were observed in either, the IBS group or the control group. Histopathological examinations showed the corrosion particles of iron were encapsulated by fibrocytes and engulfed by macrophages, indicating that the degradation of iron was in the early stage. Our results demonstrated that the nitrided iron stent did not induce systemic toxicity under the experimental conditions.