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Title: | 具有可切換形狀記憶特性之殼聚醣-生物可降解聚胺酯冷凍凝膠 A Biodegradable Chitosan-Polyurethane Cryogel with Switchable Shape Memory |
Authors: | Chih-Yu Fu 傅智煜 |
Advisor: | 徐善慧(Shan-hui Hsu) |
Keyword: | 形狀記憶聚胺酯交聯劑,形狀記憶冷凍凝膠,殼聚醣,可注射性,生物 可降解性, cryogel,polyurethane,chitosan,shape memory,injectable, |
Publication Year : | 2021 |
Degree: | 碩士 |
Abstract: | 冷凍凝膠是在單體或聚合物的冷凍溶液中形成的凝膠基質,其具有相互連通的大孔、結構穩定性和可壓縮性等的優點。同時,熱誘導形狀記憶材料在生醫領域中有著相當大的潛力,因為形狀記憶行為可以使材料被固定於小形狀並藉由微創手術植入欲修補之位置,最後通過外部刺激使材料恢復其初始之大形狀。但是,到目前為止沒有文獻報導關於形狀記憶冷凍凝膠的研究。本研究合成了具有形狀記憶特性的水基可生物降解的雙官能聚胺酯,並將其用作納米粒子交聯劑與殼聚醣相互反應形成形狀記憶冷凍凝膠。在形狀記憶過程中,使用原位廣角 X 射線散射(WAXS)和小角度 X 射線散射(SAXS)闡明了熱誘導形狀記憶的機理。原位 WAXS 在形狀固定和恢復的過程中顯示出交聯劑和冷凍凝膠的結晶度變化。原位 SAXS 揭示了交聯劑和冷凍凝膠的結晶位向,這些結晶位向在形狀記憶過程中扮演著舉足輕重的地位。本研究在不同環境下(空氣中或水中)探討形狀記憶冷凍凝膠的恢復行為。在空氣中的形狀記憶測試如下:將條形冷凍凝膠在 50℃下變形為 U 形並在-20℃環境中固定形狀,最後在 50℃的空氣中恢復為條形。在水中的形狀記憶測試如下:於空氣中將條形冷凍凝膠在 50℃下變形為 U 形並在-20℃環境中固定形狀,然後將此 U 形冷凍凝膠壓縮成團並放入 4℃的水中,冷凍凝膠在 4℃的水中預計恢復為 U 形,這意味著冷凍凝膠的彈性恢復能力;在 37℃的水中預計恢復為條型,這代表冷凍凝膠的可切換形狀記憶形狀,而藉由可切換形狀的能力,可以將尺寸較大的 10 毫米 × 10 毫米 × 1.1 毫米的片狀形狀記憶冷凍凝膠,或是複雜結構(如:字母 N、T 或是 U)的形狀記憶冷凍膠固定為棒狀,通過 16 G 針頭擠出並在 37℃的水中恢復為初始形狀。而在此形狀記憶冷凍凝膠支架中生長的人骨髓間充質幹細胞亦表現出長期的增殖能力和形成軟骨的潛能。總結來說,本研究製備了具有大尺寸或複雜結構的可注射形狀記憶可分解殼聚醣-聚胺酯冷凍凝膠,具有良好的細胞相容性,且未來在組織工程與微創手術具有應用潛力。 Cryogels are matrices that are formed in moderately frozen solutions of monomeric or polymeric precursors. They have the advantages of interconnected macropores, structural stability, and compressibility. Meanwhile, thermally induced shape memory is an attractive feature of certain functional materials. Although there have been several works concerning shape memory cryogels, little work has been done on shape memory cryogels with biodegradability. In this study, a water-based biodegradable difunctional polyurethane with shape memory property was synthesized and used as the nanoparticulate crosslinker to react with chitosan to form shape memory cryogel. The thermally-induced shape memory mechanism was clarified using in-situ wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS)during the shape memory process. The in-situ WAXS showed the changes of crystallinity in the crosslinker and the cryogel during the shape fixation and recovery processes. The in-situ SAXS revealed the orientation of crystallinity of the crosslinker and the cryogel as the mechanism for shape memory. The strip-shape cryogel was deformed at 50℃ to U-shape and fixed at - 20℃, which was squeezable at 25℃ and returned to the strip-shape at 50℃ in air. The shape recovery was further tested in water under two different temperatures. The injected cryogel recovered to the U-shape in 4℃ water, representing elastic recovery, and transformed to the long strip in 37℃ water, representing the switchable shape memory. Moreover, the shape memory cryogel sheet with a large dimension (10 mm × 10 mm × 1.1 mm cryogel sheet) or in complex structure (N, T, or U shapes) could be fixed as a rod, injected through a 16 G needle, and return to their original shapes in 37℃ water, all of which could not be achieved by the conventional cryogel. Human mesenchymal stem cells grown in the shape memory cryogel scaffolds displayed long-term proliferation and chondrogenic potential. The unique injectability and cytocompatibility suggested potential applications of shape memory cryogel as injectable and expandable templates for tissue engineering and minimally invasive surgery. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/74326 |
DOI: | 10.6342/NTU202100767 |
Fulltext Rights: | 有償授權 |
Appears in Collections: | 高分子科學與工程學研究所 |
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