Professor Yong-Gu Lee's research team develops a self-assembling medical stent by using 3D printing

□ Professor Yong-Gu Lee's research team at the School of Mechanical Engineering at the Gwangju Institute of Science and Technology (GIST, President Seung Hyeon Moon) has developed a medical stent ** production technique that can automatically transform and assemble flat structures into cylindrical structures after being created by using 4D printing technology *.

* 4D Printing: The concept of 'time' is added to the 3D printing technology so that a desired form can be created in a certain environment over a certain amount of time.

** Medical stent: A cylindrical medical device that enlarges restricted blood vessels or bile ducts and esophagus in the body to restore normal functions.

□ According to the Korea Health Industry Development Institute, the market for medical stents is expected to reach US $10 billion in 2019 and is expected to grow. Currently, government departments such as Food and Drug Administration, Ministry of Science, Technology and Information, Ministry of Health and Welfare, and Ministry of Industry and Commerce have a proactive attitude toward medical devices using 3D/4D printing technology and are planning related support projects.

∘ However, stents are currently manufactured individually using molds. This is an expensive process because it includes labor and manufacturing costs.

□ The team succeeded in fabricating a cylindrical stent using 3D printing technology by developing a technique of flattening and transforming a material into a cylindrical shape by immersing it in ethanol.

∘ The reason for the printing a flat material is because it can reduce the production time much more than printing a cylinder, and this can save money by reducing the amount of support * material.

* Support: A material that supports the structure in 3D printing.

□ In addition, special designs have helped to ensure that the deformation from a flat shape to a cylindrical shape can be achieved, and the cylindrical shape can be stable for a period of time after the transformation has been completed. The team found that the deformation was maintained for a period of time in an environment without ethanol even after the transformation was completed.

∘ Biocompatible material **, which is commercially available as a 3D printer material, automatically expands in the body due to the environment such as body temperature, pH, humidity, etc., so that the narrowed vessel or duct can be restored. And it is also possible to make individual customized shapes that can increase the effectiveness. Another great advantage is that it is easy to produce anywhere in the world without the need for a 3D printer.

** Biocompatible Material: A material that can be used inside the body without being rejected by tissues or organs.

□ Professor Lee said, "Although this is a highly marketable field, stents are the number one imported medical device in Korea. We expect this technology to contribute to replacing imports and increasing global market share."

□ This study was led by Professor Yong-Gu Lee of the School of Mechanical Engineering with Woorim Choi and Tae-Young Kim and was supported by the Ministry of Science and Technology, Ministry of Information and Communication, and by IT and SW convergence industry source technology development project for the Information and Communication Technology Promotion Center. The results of this research were published online on April 16, 2018, in Macromolecular Materials and Engineering.