Long-term in vivo corrosion behavior, biocompatibility and bioresorption mechanism of a bioresorbable nitrided iron scaffold.
Pure iron as a potential bioresorbable material for bioresorbable coronary scaffold has major disadvantages of slow corrosion and bioresorption. However, so far, there are neither quantitative data of long-term in vivo corrosion nor direct experimental evidence for bioresorption of pure iron and its alloys, which are fundamental and vital for developing novel Fe-based alloys overcoming the intrinsic drawbacks of pure iron. This work systemically investigated scaffold performance, long-term in vivo corrosion behavior and biocompatibility of a nitrided iron coronary scaffold and explored its bioresorption mechanism. It was found that the 70μm Fe-based scaffold was superior to a state of the art Co-Cr alloy stent (Xience Prime™) in terms of crossing profile, recoil and radial strength. Mass loss was 76.0±8.5wt% for the nitrided iron scaffold and 44.2±11.4wt% for the pure iron scaffold after 36months implantation in rabbit abdominal aorta (p<0.05). The Fe-based scaffold showed good long-term biocompatibility in both rabbit and porcine model. Its insoluble corrosion products were demonstrated biosafe and could be cleared away by macrophages from in situ to adventitia to be indiscernible by Micro Computed Tomography and probably finally enter the lymphatics and travel to lymph nodes after 53months implantion in porcine coronary artery. The results indicate that the nitrided iron scaffold with further improvements shall be promising for coronary application.



Pure iron as a potential bioresorbable material has major disadvantages of slow corrosion and bioresorption. However, so far, there are neither quantitative data of long-term in vivo corrosion nor direct experimental evidence for bioresorption of pure iron and its alloys. Only this work systemically investigated long-term in vivo corrosion behavior and biocompatibility of a nitrided iron coronary scaffold up to 53months after implantation and explored its bioresorption mechanism. These are fundamental and vital for developing novel Fe-based alloys overcoming the intrinsic drawbacks of pure iron. Novel testing and section-preparing methods were also provided in this work to facilitate future research and development of novel Fe-based alloy scaffolds.
College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China; R&D Center, Lifetech Scientific (Shenzhen) Co Ltd, Shenzhen 518057, China.
Wenjiao
W
Lin
R&D Center, Lifetech Scientific (Shenzhen) Co Ltd, Shenzhen 518057, China.
Li
L
Qin
R&D Center, Lifetech Scientific (Shenzhen) Co Ltd, Shenzhen 518057, China.
Haiping
H
Qi
R&D Center, Lifetech Scientific (Shenzhen) Co Ltd, Shenzhen 518057, China. Electronic address: zhangdeyuan_2012@163.com.
Deyuan
D
Zhang
R&D Center, Lifetech Scientific (Shenzhen) Co Ltd, Shenzhen 518057, China.
Gui
G
Zhang
Department of Cardiology, Fuwai Hospital, Beijing 100037, China.
Runlin
R
Gao
Department of Cardiology, Fuwai Hospital, Beijing 100037, China.
Hong
H
Qiu
R&D Center, Lifetech Scientific (Shenzhen) Co Ltd, Shenzhen 518057, China.
Ying
Y
Xia
Shenzhen Testing Center of Medical Devices, Shenzhen 518057, China.
Ping
P
Cao
College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China.
Xiang
X
Wang
College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China. Electronic address: zhengwei75@126.com.
Wei
W
Zheng
D020341:Absorbable Implants; D000818:Animals; D001011:Aorta; D001807:Blood Vessel Prosthesis; D003343:Corrosion; D058085:Iron Compounds / Q000737:chemistry*; D008297:Male; D008422:Materials Testing; D011817:Rabbits; D054457:Tissue Scaffolds / Q000737:chemistry*
D058085:Iron Compounds
Biocompatibility; Bioresorption mechanism; Fe-based alloy; In vivo corrosion profile; Scaffold performance