Researchers fabricate micro-architected coronary artery stents comprising polycaprolactone-based shape-memory polymer composite

Cardiovascular diseases constitute a major global health concern. Various complications that affect normal blood flow in arteries and veins, such as stroke, blood clot formation in veins, blood vessel rupture, and coronary artery disease, often require vascular treatments. However, existing vascular stent devices often require complex, invasive deployment procedures, making it necessary to explore novel materials and manufacturing technologies that could enable such medical devices to work more naturally with the human body. Moreover, the development of patient-specific, adaptively deployable vascular stents is crucial to further advance minimally invasive cardiovascular therapies and make vascular treatments safe and less burdensome for both patients and healthcare providers.

In an innovative breakthrough, a team of researchers from Japan and China, led by Professor Shinjiro Umezu from the Graduate School of Advanced Science and Engineering, Waseda University, Japan, has successfully developed a new 4D-printed vascular stent that expands naturally at body temperature, eliminating the need for external heating and potentially enabling safer and less invasive treatments.

The team also included Yannan Li, Yifan Pan, Chaolun Xu, Jianxian He, Jingao Xu, Dr. Kewei Song, and Dr. Ze Zhang from Waseda University, Prof. Chikahiro Imashiro and Dr. Kayo Hirose from The University of Tokyo, Japan, Dr. Chen Gao from Southeast University, China, Dr. Junbo Jiang from South China University of Technology, and Prof. Runhuai Yang from Anhui Medical University, China. Their novel findings have been published online in the journal Advanced Functional Materials on January 15, 2026.

In this study, the researchers leveraged a polycaprolactone-based shape-memory polymer composite to fabricate micro-architected coronary artery stents through projection micro-stereolithography 4D printing technology. This technology utilizes ultraviolet light to create micro-sized objects with high-resolution features. Scientists used this technology to create such micro-coronary artery stents. Notably, they precisely modulated the thermal transition temperature to approximately 37 °C by utilizing diethyl phthalate as a plasticizer, facilitating quick and automatic shape recovery with no external heating.

Finite element simulations and a viscoelastic stress relaxation model confirm that the developed stents remarkably balance mechanical flexibility and radial strength, and demonstrate long-term biomechanical compliance. Moreover, while in vitro studies using human umbilical cells exhibited excellent cytocompatibility, in vivo implantation experiments in mice indicated the potential for clinical application.

Prof. Umezu points out the immense potential of their innovative next-generation technology. “Our work provides a robust platform for next-generation adaptive vascular stents with programmable mechanics, intelligent deployment, smoother integration with human body, and reduced need for complex procedures, offering significant potential for personalized treatment in anatomically complex vascular structure.”

The present work may help address challenges in vascular treatments and could be utilized in other implantable medical devices. The coronary artery stents developed in this study highlights high operational feasibility and engineering controllability. These advantages also demonstrate highly tunable and personalized fabrication of stents for diverse patient groups. The findings of the study showcase a generalized approach for the development of vascular implants, with significant potential for clinical translation.

“Consequently, our research could contribute to future vascular stent technologies used in minimally invasive procedures, potentially simplifying deployment and reducing the need for additional equipment. The same approach may be applicable to other implantable medical devices that are designed to respond to the body’s natural environment,” highlights Prof. Umezu.

Reference
Authors: Yannan Li^a, Yifan Pan^b, Chikahiro Imashiro^c, Chaolun Xu^b, Jianxian He^b, Jingao Xu^b, Kewei Song^b, Ze Zhang^b, Chen Gao^e, Junbo Jiang^f, Runhuai Yang^g, Kayo Hirose^d, and Shinjiro Umezu^a,b
Title of original paper: Adaptive 4D-Printed Vascular Stents with Low-Temperature-Activated and Intelligent Deployment
Journal: Advanced Functional Materials
DOI: 10.1002/adfm.202521468
Affiliations: ^aGraduate School of Advanced Science and Engineering, Department of Integrative Bioscience and Biomedical Engineering, Waseda University, Japan
^bGraduate School of Creative Science and Engineering, Department of Modern Mechanical Engineering, Waseda University, Japan
^c Graduate School of Engineering, The University of Tokyo, Japan
^dAnesthesiology and Pain Relief Center, The University of Tokyo Hospital, Japan
^eSchool of Biological Science and Medical Engineering, Southeast University, China
^fDepartment of Rehabilitation Medicine, Guangzhou First People’s Hospital, School of Medicine, South China University of Technology, China
^gThe Chaohu Hospital of Anhui Medical University, China


About Waseda University
Located in the heart of Tokyo, Waseda University is a leading private research university that has long been dedicated to academic excellence, innovative research, and civic engagement at both the local and global levels since 1882. The University has produced many changemakers in its history, including eight prime ministers and many leaders in business, science and technology, literature, sports, and film. Waseda has strong collaborations with overseas research institutions and is committed to advancing cutting-edge research and developing leaders who can contribute to the resolution of complex, global social issues. The University has set a target of achieving a zero-carbon campus by 2032, in line with the Sustainable Development Goals (SDGs) adopted by the United Nations in 2015.

To learn more about Waseda University, visit https://www.waseda.jp/top/en


About Professor Shinjiro Umezu
Dr. Shinjiro Umezu is a Professor at Waseda University, Japan. He is affiliated with both the Graduate School of Advanced Science and Engineering, Department of Integrative Bioscience and Biomedical Engineering, as well as the Graduate School of Creative Science and Engineering, Department of Modern Mechanical Engineering. His research interests include mechanical engineering, mechanics and mechatronics, robotics and intelligent systems, green fabrication, biofabrication, and 3D printing. He has published about 300 research papers on these topics and received more than 2,000 citations. He is a member of Japanese Society of Mechanical Engineers and Society of Precision Engineering.