Biodegradable shape-memory block co-polymers for fast self-expandable stents
✍ Scribed by Liang Xue; Shiyao Dai; Zhi Li
- Book ID
- 104004015
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 945 KB
- Volume
- 31
- Category
- Article
- ISSN
- 0142-9612
No coin nor oath required. For personal study only.
✦ Synopsis
Block co-polymers PCTBVs (M n of 36,300e65,300 g/mol, T m of 39e40 and 142 C) containing hyperbranched three-arm poly(3-caprolactone) (PCL) as switching segment and microbial polyester PHBV as crystallizable hard segment were designed as biodegradable shape-memory polymer (SMP) for fast selfexpandable stent and synthesized in 96% yield by the reaction of three-arm PCL-triol (M n of 4200 g/mol, T m of 47 C) with methylene diphenyl 4,4 0 -diisocyanate isocynate (MDI) to form the hyperbrached MDIlinked PCL (PTCM; M n of 25,400 g/mol and a T m of 38 C), followed by further polymerization with PHBVdiol (M n of 2200 g/mol, T m of 137 and 148 C). The polymers were characterized by 1 H NMR, GPC, DSC, tensile test, and cyclic thermomechanical tensile test. PCTBVs showed desired thermal properties, mechanical properties, and ductile nature. PCTBV containing 25 wt% PHBV (PCTBV-25) demonstrated excellent shape-memory property at 40 C, with R f of 94%, R r of 98%, and shape recovery within 25s. PCTBV-25 was also shown as a safe material with good biocompatibility by cytotoxicity tests and cell growth experiments. The stent made from PCTBV-25 film showed nearly complete self-expansion at 37 C within only 25 s, which is much better and faster than the best known self-expandable stents.