Design and characterization of a novel biocorrodible iron-based drug-eluting coronary scaffold

Long corrosion period and slow resorption in vivo remain major limitations for iron-based bioresorbable scaffolds. This work focused on the design and characterization of a novel iron-based drug-eluting coronary scaffold (IBS scaffold) made of nitrided iron materials. The 53 μm IBS scaffold shows good device performance comparable to a current mainstream drug-eluting coronary stent (Xience Prime™) due to the good comprehensive mechanical performance of nitrided iron materials. The novel design of a zinc barrier layer makes it possible for the IBS scaffold to have ultrathin struts and thick PDLLA coating of 12 μm to maintain adequate scaffolding (125 kPa) after 3 months implantation while having a significantly shortened corrosion period (13 months). The biocorrosion and bioresorption of the IBS scaffold could be effectively evaluated using Micro-CT, OCT and MRI methods. Although complete bioresorption of the corrosion products has not been observed yet, there are no identified biological problems for the IBS scaffold after implantation in rabbit abdominal aorta up to 13 months. This study demonstrates that the IBS scaffold with novel design has significantly shortened corrosion period and less amount of corrosion products without causing any biological problems after implantation up to 13 months, therefore is promising for coronary application.