Researchers from Japan and China have developed innovative 4D printed vascular stents that expand naturally at body temperature, eliminating the need for external heating and potentially enabling safer and less invasive cardiovascular treatments, according to findings published on Wednesday, January 15 in the journal Advanced Functional Materials.
The breakthrough addresses a critical global health challenge, as cardiovascular diseases (CVDs) remain the leading cause of death worldwide, responsible for 19.2 million deaths in 2023 according to data from the Global Burden of Disease study. Approximately 80 percent of cardiovascular disease deaths occur in low and middle income countries, where access to advanced medical treatments remains limited.
The research team, led by Professor Shinjiro Umezu from the Graduate School of Advanced Science and Engineering at Waseda University in Japan, successfully fabricated micro architected coronary artery stents through projection micro stereolithography 4D printing technology using a polycaprolactone based shape memory polymer composite.
Existing vascular stent devices often require complex, invasive deployment procedures, making it necessary to explore novel materials and manufacturing technologies that could enable medical devices to work more naturally with the human body. The development of patient specific, adaptively deployable vascular stents is crucial to advance minimally invasive cardiovascular therapies and make vascular treatments safe and less burdensome for both patients and healthcare providers.
The researchers precisely modulated the thermal transition temperature to approximately 37 degrees Celsius by utilizing diethyl phthalate as a plasticizer, facilitating quick and automatic shape recovery without external heating. This innovation represents a significant departure from traditional stent deployment methods that often require balloon catheters or other mechanical devices to expand the stent within blood vessels.
Projection micro stereolithography 4D printing technology utilizes ultraviolet light to create micro sized objects with high resolution features. Scientists used this technology to create coronary artery stents measuring just millimeters in diameter. The fourth dimension refers to the stent’s ability to change shape over time in response to body temperature.
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. In vitro studies using human umbilical cells exhibited excellent cytocompatibility, while in vivo implantation experiments in mice indicated strong potential for clinical application.
Professor Umezu emphasized the immense potential of the 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, Umezu stated.
The research team included Yannan Li, Yifan Pan, Chaolun Xu, Jianxian He, Jingao Xu, Dr. Kewei Song, and Dr. Ze Zhang from Waseda University, Professor Chikahiro Imashiro and Dr. Kayo Hirose from The University of Tokyo, Dr. Chen Gao from Southeast University in China, Dr. Junbo Jiang from South China University of Technology, and Professor Runhuai Yang from Anhui Medical University in China.
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, blood vessel rupture, and coronary artery disease, often require vascular treatments. Traditional stent materials and deployment techniques have improved patient outcomes significantly over the past three decades, but challenges including restenosis, thrombosis, and the need for invasive procedures persist.
The coronary artery stents developed in this study exhibit high operational feasibility and engineering controllability. These advantages demonstrate highly tunable and personalized fabrication of stents for diverse patient groups. The findings showcase a generalized approach for the development of vascular implants, with significant potential for clinical translation.
Professor Umezu stated the 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.
Shape memory polymers have emerged as promising materials for biomedical applications due to their ability to recover their original shape when triggered by specific stimuli such as temperature, light, or chemical signals. The polycaprolactone based composite used in this research offers biocompatibility, biodegradability, and precisely tunable mechanical properties.
The American Heart Association released updated cardiovascular disease statistics in January 2026 showing 626 million prevalent cases of cardiovascular disease globally in 2023, more than double the 311 million cases recorded in 1990. Ischemic heart disease, intracerebral hemorrhage, ischemic stroke, and hypertensive heart disease remain the leading cardiovascular causes of disability adjusted life years worldwide.
Waseda University, located in Tokyo, is a leading private research university that has maintained dedication to academic excellence and innovative research since its founding in 1882. The university has produced eight prime ministers and numerous leaders in business, science, technology, literature, sports, and film.
Professor Umezu is affiliated with both the Graduate School of Advanced Science and Engineering, Department of Integrative Bioscience and Biomedical Engineering, and the Graduate School of Creative Science and Engineering, Department of Modern Mechanical Engineering at Waseda University. His research interests include mechanical engineering, mechanics and mechatronics, robotics and intelligent systems, green fabrication, biofabrication, and 3D printing. He has published approximately 300 research papers and received more than 2,000 citations.
The study was published in Advanced Functional Materials under the title Adaptive 4D Printed Vascular Stents with Low Temperature Activated and Intelligent Deployment with digital object identifier 10.1002/adfm.202521468.
