Biodegradable vascular stents with high tensile and compressive strength: a novel strategy for applying monofilaments via solid-state drawing and shaped-annealing processes
- Authors
- Im, Seung Hyuk; Kim, Chang Yong; Jung, Youngmee; Jang, Yangsoo; Kim, Soo Hyun
- Issue Date
- 1-3월-2017
- Publisher
- ROYAL SOC CHEMISTRY
- Citation
- BIOMATERIALS SCIENCE, v.5, no.3, pp.422 - 431
- Indexed
- SCIE
SCOPUS
- Journal Title
- BIOMATERIALS SCIENCE
- Volume
- 5
- Number
- 3
- Start Page
- 422
- End Page
- 431
- URI
- https://scholar.korea.ac.kr/handle/2021.sw.korea/84180
- DOI
- 10.1039/c7bm00011a
- ISSN
- 2047-4830
- Abstract
- Monofilaments such as those consisting of polyamide (PA), polydioxanone (PDS), and poly(vinylidene fluoride) (PVDF), have been commonly used in various industries. However, most are non-biodegradable, which is unfavorable for many biomedical applications. Although biodegradable polymers offer significant benefits, they are still limited by their weak mechanical properties, which is an obstacle for use as a biomaterial that requires high strength. To overcome the current limitations of biodegradable monofilaments, a novel solid-state drawing (SSD) process was designed to significantly improve the mechanical properties of both PA and poly(L-lactic acid) (PLLA) monofilaments in this study. Both PA and PLLA monofilaments exhibited more than two-fold increased tensile strength and a highly reduced thickness using SSD. In X-ray diffraction and scanning electron microscopy analyses, it was determined that SSD could not only promote the a-crystal phase, but also smoothen the surface of PLLA monofilaments. To apply SSD-monofilaments with superior properties to cardiovascular stents, a shaped-annealing (SA) process was designed as the follow-up process after SSD. Using this process, three types of vascular stents could be fabricated, composed of SSD-monofilaments: double-helix, single-spring and doublespring shaped stents. The annealing temperature was optimized at 80 degrees C to minimize the loss of mechanical and physical properties of SSD-monofilaments for secondary processing. All three types of vascular stents were tested according to ISO 25539-2. Consequently, it was confirmed that spring-shaped stents had good recovery rate values and a high compressive modulus. In conclusion, this study showed significantly improved mechanical properties of both tensile and compressive strength simultaneously and extended the potential for biomedical applications of monofilaments.
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Collections - Graduate School > KU-KIST Graduate School of Converging Science and Technology > 1. Journal Articles
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