本文選題：細菌纖維素納米晶須 + 溫敏性��； 參考：《華中科技大學(xué)》2016年博士論文

【摘要】：細菌纖維素(Bacterial Cellulose,BC)是木醋桿菌生產(chǎn)的天然高分子材料,擁有納米纖維組成的三維網(wǎng)絡(luò)結(jié)構(gòu)。通過β-(1,4)-糖苷鍵鏈接而成的纖維素高分子鏈,表面具有大量的羥基基團,容易通過各種化學(xué)方法進行功能性修飾,其中包括高分子接枝反應(yīng)(耦合接枝和引發(fā)接枝)、陽離子化反應(yīng)以及其他共價和非共價的反應(yīng)。BC兼具優(yōu)良的生物相容性、高結(jié)晶度以及良好的機械性能等獨特的理化性質(zhì),在化工和醫(yī)用材料等領(lǐng)域具有廣闊的應(yīng)用前景。為了進一步拓展BC在醫(yī)用材料方面的應(yīng)用前景,本文制備了納米尺寸的細菌纖維素(細菌纖維素納米晶須,Bacterial Cellulose Nanowhisker,BCNW),通過溫敏性高分子對其進行功能性修飾,得到新的具有溫敏性的生物材料,并對該生物材料作為栓塞材料的潛在應(yīng)用前景進行了初步的研究。本文首先對酸水解和冷凍研磨制備BCNW的方法進行比較,結(jié)果顯示酸水解的方法能夠更徹底的破壞BC膜的網(wǎng)絡(luò)結(jié)構(gòu)得到納米尺寸的BCNW;對BC的親水性、持水性、機械性能以及生物相容性進行測試,結(jié)果表明BC具有很好的親水性和持水性(含水量達97%),擁有典型的水凝膠性質(zhì),展現(xiàn)出良好的生物相容性。接下來,通過原子轉(zhuǎn)移自由基聚合(Atom Transfer Radical Polymerization,ATRP)將最具有標志性的溫敏聚合物聚N-異丙基丙烯酰胺(PNIPAM)引發(fā)聚合在納米晶須的表面形成溫敏共聚物BCNW-g-PNIPAM。通過傅立葉轉(zhuǎn)換紅外光譜和核磁共振氫譜證明了該聚合作用的成功性。經(jīng)透射電鏡展示了其納米結(jié)構(gòu)伴隨溫度的變化而產(chǎn)生的差異。差示掃描量熱法證明該共聚物具有溫敏性質(zhì),并且其低臨界溶解溫度依然低于人體溫度。細胞毒性實驗表明了BCNW對于提高材料的生物相容性的重要性。本文進一步研究,選擇生物相容性較好的溫敏高分子聚2-甲基-2-丙烯酸-2-(2-甲氧基乙氧基)乙酯(PMEO_2MA)進行相關(guān)溫敏納米材料的制備。通過ATRP的聚合方法得到具有溫敏性質(zhì)的BCNW-g-PMEO_2MA,并通過傅立葉轉(zhuǎn)換紅外光譜和核磁共振氫譜證明了該聚合作用的成功性。濁度法測試表明該共聚物的低臨界溶解溫度為28.5℃。然后添加寡聚乙二醇甲基丙烯酸酯(OEGMA)與PMEO_2MA進行共混聚合,接枝到BCNW表面,通過控制兩種單體共混聚合的比例,得到了低臨界溶解溫度為31.5℃的溫敏性共聚物BCNW-g-P(OEGMA-co-MEO_2MA)。BCNW-gPMEO_2MA與BCNW-g-P(OEGMA-co-MEO_2MA)的低臨界溶解溫度都展現(xiàn)出離子依賴性。共聚物的細胞毒性實驗證明其細胞相容性更好,所以該溫敏共聚物具有作為栓塞材料的潛力。
[Abstract]:Bacterial cellulose (Bacterial Celluloseus) is a natural polymer material produced by Acetobacter xylophilus, which has a three-dimensional network structure composed of nanofibers. A chain of cellulose polymers linked by 尾 -chlorion 4- glucoside bonds has a large number of hydroxyl groups on the surface, and it is easy to be modified by various chemical methods. It includes polymer graft reaction (coupling grafting and initiating grafting, cationic reaction and other covalent and non-covalent reactions. BC has excellent biocompatibility, high crystallinity and good mechanical properties, etc.) It has a broad application prospect in the fields of chemical industry and medical materials. In order to further expand the application prospect of BC in medical materials, we prepared bacterial cellulose (bacterial Cellulose nanowhisker BCNWN) with nanometer size, and modified it by thermo-sensitive polymers. A new thermosensitive biomaterial was obtained and the potential application prospect of the biomaterial as an embolic material was preliminarily studied. In this paper, the methods of preparing BCNW by acid hydrolysis and freezing grinding are compared. The results show that the method of acid hydrolysis can destroy the network structure of BC membrane more thoroughly to obtain nano-size BCNW. The mechanical properties and biocompatibility of BC were tested. The results showed that BC had good hydrophilicity and water holdup (water content was 97%, typical hydrogel property, and showed good biocompatibility. Next, the most iconic thermo-sensitive polymer, poly (N-isopropylacrylamide) PNIPAM, was initiated by atom transfer radical polymerization (Atom Transfer Radical Polymerization) to form a thermo-sensitive copolymer BCNW-g-PNIPAM on the surface of nano-whiskers. The success of the polymerization was proved by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). Transmission electron microscopy (TEM) shows the difference between the nanostructures and the temperature. The differential scanning calorimetry (DSC) shows that the copolymer has the property of temperature sensitivity and its low critical solution temperature is still lower than the human body temperature. Cytotoxicity tests show the importance of BCNW in improving the biocompatibility of materials. In this paper, a thermo-sensitive polymer, poly (2-methyl-2-acrylic acid) -2-methoxy ethoxy ethyl ester (PMEO _ 2MA) with good biocompatibility, was selected to prepare the thermo-sensitive nano-materials. The thermo-sensitive BCNW-g-PMEO2MAwas obtained by the polymerization of ATRP. The success of the polymerization was proved by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) hydrogen spectroscopy. The turbidimetric test showed that the low critical solution temperature of the copolymer was 28.5 鈩，

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