本文選題：聚氨酯 + 形狀記憶過程��； 參考：《重慶大學》2016年博士論文

【摘要】：形狀記憶聚氨酯(SMPU)具有良好的生物相容性、力學性能和形狀記憶性能,在生物醫(yī)學領(lǐng)域備受關(guān)注。SMPU軟段與硬段因熱力學不相容而形成的相分離微納結(jié)構(gòu)是其具有形狀記憶效應(yīng)(SME)的結(jié)構(gòu)基礎(chǔ),而賦形、固定和形狀回復則是其體現(xiàn)SME的必需過程。賦形和回復這兩個動態(tài)過程可改變相分離微納結(jié)構(gòu);回復過程還可產(chǎn)生回復應(yīng)變。為了更深入地理解SME對SMPU生物相容性的影響機制,指導SMPU的結(jié)構(gòu)設(shè)計和加工,需深入認識SMPU形狀記憶過程中相分離微納結(jié)構(gòu)的變化及其與回復應(yīng)變對細胞行為的調(diào)控。但迄今為止,尚缺乏相關(guān)研究。本文采用廣角X射線衍射(WAXD)、小角X射線散射(SAXS)、傅里葉全反射紅外光譜(ATR-FTIR)、差示掃描量熱(DSC)、原子力顯微鏡(AFM)、掃描電鏡(SEM)等技術(shù)考察了拉伸賦形與形狀回復過程對SMPU薄膜相分離微納結(jié)構(gòu)的影響及影響機制,并以成骨細胞為模型細胞考察了微納結(jié)構(gòu)與回復應(yīng)變對細胞形態(tài)的調(diào)控作用。主要研究內(nèi)容和結(jié)論如下:(1)拉伸賦形對SMPU薄膜微納結(jié)構(gòu)的影響本文采用軟段為聚乳酸-聚乙二醇三嵌段共聚物(PDLLA-PEG-PDLLA),硬段為六亞甲基二異氰酸酯(HDI)和哌嗪(PPZ)的嵌段SMPU作為模型材料,以聚(DL-乳酸)(PDLLA)為對照材料,采用溶液澆注法制備SMPU和PDLLA薄膜,考察拉伸賦形(拉伸率為0%,50%,100%,200%)對SMPU相分離微納結(jié)構(gòu)的影響,為深入理解賦形對細胞形態(tài)的調(diào)控及調(diào)控機理奠定基礎(chǔ)。(1)未賦形SMPU薄膜具有明顯的相分離結(jié)構(gòu),硬段逐級聚集形成硬段微區(qū)、獨立“島”結(jié)構(gòu)和納米纖維,在軟段相中形成無序的硬段相化學“圖案”;而對照材料PDLLA薄膜表面均一、平滑,僅出現(xiàn)因微弱結(jié)晶而導致的相分離現(xiàn)象。(2)拉伸賦形使光滑的PDLLA表面出現(xiàn)了垂直于拉伸方向排列的納米突起。而在SMPU表面,拉伸賦形導致硬段微區(qū)與“島”結(jié)構(gòu)的長軸垂直于拉伸方向并且沿拉伸方向聚集,最終導致納米纖維平行于拉伸方向,表明拉伸賦形可以改變SMPU的表面微納結(jié)構(gòu)并提高納米纖維的有序性,提示對SMPU拉伸賦形可望成為一種制備有序化學“圖案”的新方法。(2)拉伸賦形所致相分離微納結(jié)構(gòu)對細胞粘附與蛋白吸附的影響分別以成骨細胞和纖連蛋白(Fn)為模型細胞和模型蛋白,采用免疫熒光染色技術(shù)考察拉伸誘導的微納結(jié)構(gòu)對細胞形態(tài)與蛋白吸附的影響。結(jié)果顯示:細胞長軸與Fn組裝的蛋白纖維在SMPU薄膜表面均平行于拉伸方向,而在PDLLA薄膜表面則均垂直于拉伸方向,表明拉伸誘導的表面微納結(jié)構(gòu)可以調(diào)控細胞取向與蛋白組裝,提示賦形處理可影響SMPU材料-細胞相互作用。同時,該結(jié)果進一步證實,拉伸賦形可成為一種制備有序化學“圖案”以調(diào)控細胞行為的新方法。(3)回復介質(zhì)對薄膜形狀回復與微納結(jié)構(gòu)的調(diào)控回復過程是SMPU體現(xiàn)形狀變化的過程,在醫(yī)學應(yīng)用中通常是在體液環(huán)境中發(fā)生。考察體液回復環(huán)境對SMPU相分離微納結(jié)構(gòu)和形狀回復的影響及其機制,可為全面、深入地理解SMPU生物相容性提供理論基礎(chǔ),也可指導SMPU醫(yī)學應(yīng)用方案的制定。因此,本研究將拉伸賦形SMPU薄膜兩端固定以保持應(yīng)變恒定,將其置于32°C空氣或細胞培養(yǎng)液DMEM中靜置24h;隨后,去除薄膜兩端固定裝置并分別升高空氣或DMEM的溫度使薄膜自由回復。通過考察介質(zhì)環(huán)境對薄膜形狀回復和表面微納結(jié)構(gòu)的影響,探討體液環(huán)境影響SMPU形狀記憶過程的相關(guān)機理�！笆芟蕖碧幚碇荚谑贡∧そ�(jīng)歷薄膜-細胞復合物在形狀回復之前的處理過程(詳見(4)),以便更準確地理解材料回復對細胞行為的調(diào)控機制。(1)定量檢測了回復力和回復率的動態(tài)變化,發(fā)現(xiàn)薄膜在前20 min回復較快,在2 h內(nèi)方可完成回復�！笆芟蕖碧幚韺熨x形薄膜的表面微納結(jié)構(gòu)無顯著影響,但會因為應(yīng)力松弛而降低薄膜形狀回復力和回復率。薄膜在DMEM中的形狀回復力和回復率明顯低于空氣中,DSC分析表明其機制與水分子增塑SMPU鏈段而導致應(yīng)力松弛增強有關(guān)。上述結(jié)果表明,介質(zhì)環(huán)境對形狀回復性能有明顯影響。(2)在空氣中回復時,薄膜表面的硬段組裝未完全回復到無序狀態(tài),多數(shù)納米纖維與拉伸方向呈40°夾角排列,這與應(yīng)力松弛導致的薄膜形狀未完全回復有關(guān);而在DMEM中回復時,薄膜表面硬段聚集增強,出現(xiàn)明顯的纖維狀和點狀硬段微區(qū),且納米纖維與拉伸方向間的夾角也多高于40°,這可能與水分子增塑引起的不完全回復以及水分子與軟段形成的氫鍵作用有關(guān)。上述結(jié)果表明,回復介質(zhì)明顯影響SMPU薄膜的表面微納結(jié)構(gòu),這為后續(xù)深入理解回復過程對細胞行為的影響奠定了基礎(chǔ)。(4)薄膜形狀回復應(yīng)變與微納結(jié)構(gòu)對細胞形態(tài)的調(diào)控回復應(yīng)變可能對細胞施加持續(xù)力學刺激。因此,考察回復應(yīng)變對細胞行為的調(diào)控作用,可為SMPU生物相容性的評價提供一條基于生物力學的新思路。為考察回復應(yīng)變和微納結(jié)構(gòu)對細胞形態(tài)的調(diào)控作用,本研究將成骨細胞接種于拉伸賦形SMPU薄膜表面,于32°C下培養(yǎng)24h后去除薄膜兩端固定裝置,并將薄膜-細胞復合物轉(zhuǎn)入37°C細胞培養(yǎng)箱中讓薄膜自由回復。利用活細胞工作站追蹤細胞對薄膜形狀回復的響應(yīng),并用免疫熒光染色技術(shù)觀察薄膜回復后成骨細胞形態(tài)隨培養(yǎng)時間的變化,利用CCK-8技術(shù)初步考察薄膜形狀回復對成骨細胞后期(1-7d)增殖行為的影響。(1)SMPU薄膜回復的總應(yīng)變隨拉伸率增加而增大,拉伸率為50%、100%和200%時其回復總應(yīng)變(%)分別為17.55±3.34、27.87±2.93和34.80±2.60。(2)活細胞工作站和免疫熒光染色結(jié)果顯示:在薄膜回復初期(≤4h),SMPU回復應(yīng)變使成骨細胞趨于垂直于拉伸方向排列,且細胞取向變化與拉伸率有關(guān),表明SMPU回復應(yīng)變作為一種力刺激可以調(diào)控成骨細胞形態(tài)。(3)SMPU薄膜形狀回復24h后,細胞取向與薄膜表面納米纖維取向一致,表明隨著細胞培養(yǎng)時間的延長,回復應(yīng)變對細胞取向的調(diào)控作用會逐漸被基底微納結(jié)構(gòu)所取代。(4)CCK-8檢測結(jié)果顯示,薄膜形狀回復后1-7天內(nèi),回復薄膜表面的細胞數(shù)明顯高于未回復薄膜表面。該結(jié)果表明,回復應(yīng)變可以作為一種力學刺激調(diào)控細胞形態(tài)并促進細胞增殖,SMPU可望用作一種新型的動態(tài)細胞培養(yǎng)基底。綜上所述,本論文在系統(tǒng)考察賦形、回復和回復介質(zhì)對SMPU相分離微納結(jié)構(gòu)調(diào)控的基礎(chǔ)上,揭示了SMPU形狀記憶過程中其微納結(jié)構(gòu)與回復應(yīng)變對細胞形態(tài)的調(diào)控及相關(guān)機理,為深入理解SMPU生物相容性提供了理論基礎(chǔ),相關(guān)研究結(jié)果對SMPU材料的設(shè)計與加工具有明顯的指導意義。同時,本論文也初步驗證了SMPU在有序圖案化加工技術(shù)和動態(tài)細胞培養(yǎng)系統(tǒng)中的潛在應(yīng)用價值。
[Abstract]:Shape memory polyurethane (SMPU) has good biocompatibility, mechanical properties and shape memory properties. In the biomedical field, the phase separation micro nano structure formed by the thermodynamic incompatibility between the.SMPU soft segment and the hard segment is the structural basis of the shape memory effect (SME), while the shape, the fixed and the shape recovery are the embodiment of the SME. The two dynamic processes can change the phase separation micro nano structure, and the recovery process can also produce the response strain. In order to understand the mechanism of the effect of SME on the biocompatibility of SMPU, and to guide the structure design and processing of SMPU, it is necessary to understand the changes of the phase separation microstructure in the memory process of the SMPU shape and its relationship. Back strain regulation on cell behavior. But so far, there is a lack of relevant research. In this paper, wide angle X ray diffraction (WAXD), small angle X ray scattering (SAXS), Fourier total reflection infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), atomic force microscopy (AFM), scanning electron microscopy (SEM) and other techniques have been used to investigate the process of shape and shape recovery. The influence and influence mechanism of SMPU thin film phase separation micro nano structure and the effect of osteoblast on the regulation of cell morphology by micro nano structure and response strain. The main research contents and conclusions are as follows: (1) the effect of stretching on the microstructure of SMPU thin films in this paper is the soft segment of polylactic acid polyethylene glycol block copolymerization The hard segment (PDLLA-PEG-PDLLA), the block SMPU of six methylene diisocyanate (HDI) and piperazine (PPZ) was used as model material, and SMPU and PDLLA thin films were prepared by solution pouring method with poly (DL- lactic acid) (PDLLA) as the control material. The effect of tensile morphology (tensile rate of 0%, 50%, 100%, 200%) on the microstructure of SMPU phase separation was investigated. The shape has laid the foundation for the regulation and regulation mechanism of cell morphology. (1) the unshaped SMPU film has a distinct phase separation structure, hard segments gather to form hard segments, independent "island" structure and nanofibers, forming a disordered hard phase chemical "pattern" in the soft segment, while the surface of the control material PDLLA film is homogeneous and smooth. The phenomenon of phase separation caused by weak crystallization. (2) stretching and forming the smooth surface of the PDLLA surface appears to be a nano projection perpendicular to the direction of tension. On the SMPU surface, the stretch forming causes the hard segment and the long axis of the "island" structure to be perpendicular to the tensile direction and gather along the tensile direction, eventually leading to the nanofibers parallel to the direction of tension. It is indicated that stretching can change the surface microstructure of SMPU and improve the order of nanofibers. It is suggested that the shape of SMPU can be a new method to prepare the ordered chemical "pattern". (2) the effects of the phase separation microstructures on the cell adhesion and protein adsorption are osteoblasts and fibronectin (Fn), respectively. The effects of tensile induced micro nanostructures on cell morphology and protein adsorption were investigated by immunofluorescence staining. The results showed that the protein fibers assembled by the long axis of the cell and Fn were parallel to the direction of tension on the surface of the SMPU film, while the surface of the PDLLA film was perpendicular to the tensile direction, indicating that the tensile induction was induced. Surface microstructures can regulate cell orientation and protein assembly, suggesting that shaped treatment can affect the interaction between SMPU materials and cells. At the same time, the result further confirms that stretching can be a new method to prepare ordered chemical "patterns" to regulate cell behavior. (3) the control of the shape recovery and microstructure of the membrane by the recovery medium. The process of recovery is the process of shape change in SMPU, which usually occurs in the body fluid environment in medical applications. The effect of the body fluid recovery environment on the SMPU phase separation and the shape recovery and its mechanism can provide a theoretical basis for comprehensive and in-depth understanding of the biocompatibility of SMPU, and also guide the formulation of the SMPU medical application. Therefore, the tension - shaped SMPU film is fixed at both ends to keep the strain constant, and 24h is placed in the 32 degree C air or cell culture solution DMEM. Then, the film is removed and the temperature of the air or DMEM is elevated to the free recovery of the film. The film shape recovery and the surface micronano structure are investigated by the investigation of the medium environment. The influence of the body fluid environment on the SMPU shape memory process. "Limited" treatment aims to make the film undergo the process of the membrane cell complex before the shape recovery (4), in order to more accurately understand the regulation mechanism of the material response to the cell behavior. (1) the quantitative detection of the dynamic changes in the recovery and recovery rate It is found that the film has a fast recovery in the first 20 min and can complete the recovery in 2 h. "Limited" treatment has no significant effect on the surface microstructure of the stretched thin film, but it will reduce the shape recovery force and recovery rate because of the stress relaxation. The shape recovery force and recovery rate of the thin film in DMEM are obviously lower than that in the air, and the DSC analysis shows that the mechanism of the film is lower than that in the air. The results show that the medium environment has an obvious influence on the shape recovery performance. (2) the hard segment assembly of the surface of the film is not completely recovered to the disorder state, and most nanofibers are arranged in a 40 degree angle in the direction of tensile, which is caused by the stress relaxation in the air. (2) in the air, the hard segment assembly of the film surface is not completely recovered to the disordered state. The film shape is not fully recovered, but when the DMEM is recovered, the hard segment aggregation of the film surface is enhanced, and the fiber and spot hard segments appear obviously, and the angle between the nanofibers and the tensile direction is more than 40 degrees. This may be related to the incomplete recovery caused by the plasticization of water molecules and the hydrogen bond formed by the water molecules and the soft segments. The results show that the recovery medium obviously affects the surface micro nano structure of SMPU film, which lays the foundation for further understanding the effect of the recovery process on the cell behavior. (4) the response strain of the film shape recovery and the response strain of the microstructures to the cell morphology may be stimulated by the continued mechanical stimulation of the cells. Therefore, the response strain to the cells is investigated. The regulation of behavior can provide a new idea based on biomechanics for the evaluation of biocompatibility of SMPU. In order to investigate the regulation of response strain and micro nano structure on the cell morphology, the osteoblasts were inoculated on the surface of the stretched SMPU thin film. After the culture of 24h under 32 degree C, the two ends fixtures were removed and thin film thin films were removed. The cell complex was transferred into the 37 degree C cell culture box to make the film free recovery. The response of the cells to the film shape recovery was traced by the live cell workstation. The changes of the morphology of the osteoblasts were observed with the immunofluorescence staining technique, and the CCK-8 technique was used to examine the shape recovery of the film to the later stage of osteoblast (1-7d). The effect of proliferation behavior. (1) the total strain of SMPU film was increased with the increase of tensile rate, and the total strain was 50%, 100% and 200% (%) were 17.55 + 3.34,27.87 + 2.93 and 34.80 + 2.60. (2), respectively, and the results of immunofluorescence staining showed that at the early stage of the film recovery (less than 4h), the SMPU response strain made osteoblasts. The change of the cell orientation was related to the tensile rate in the vertical direction. It showed that the SMPU response strain could regulate the morphology of osteoblasts as a kind of force stimulation. (3) after the shape of SMPU film returned to 24h, the orientation of cell orientation was consistent with the orientation of nanofiber on the surface of the film. The control effect is gradually replaced by the basal microstructure. (4) the results of CCK-8 detection show that the number of cells on the surface of the film is significantly higher than that of the unrecovered membrane within 1-7 days after the shape of the film is restored. The results show that the response strain can be used as a mechanical stimulus to regulate cell morphology and promote cell proliferation, and SMPU is expected to be used as a new kind of new type of cell. On the basis of the systematic investigation of the regulation of the SMPU phase separation structure, this paper reveals the regulation and mechanism of the micro nano structure and the response strain on the cell morphology in the process of SMPU shape memory, and provides a theoretical basis for understanding the biocompatibility of SMPU in depth. The relevant research results have obvious guiding significance for the design and processing of SMPU materials. At the same time, this paper also preliminarily verifies the potential application value of SMPU in the ordered patterned processing technology and the dynamic cell culture system.
【學位授予單位】：重慶大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：R318.08

【參考文獻】

相關(guān)期刊論文 前5條

1 王品品;王遠亮;李玉筱;馬宇飛;嚴維維;羅彥鳳;;新型組織工程用反應(yīng)性聚氨酯的合成與表征[J];材料導報;2013年12期

2 易國斌;王永亮;康正;崔亦華;廖兵;;兩親性PVP/PCL水凝膠中水的狀態(tài)[J];高分子材料科學與工程;2008年12期

3 朱冬妹;王飛;徐正;;利用疏水作用和熱敏性相分離構(gòu)筑聚合物核殼結(jié)構(gòu)和空心球[J];南京大學學報(自然科學版);2007年05期

4 吳丹;丁寅;王琪;;流體剪切力對大鼠成骨細胞增殖及細胞周期的影響[J];臨床口腔醫(yī)學雜志;2007年04期

5 曾躍民 ,胡金蓮 ,嚴灝景;Temperature Dependency of Water Vapor Permeability of Shape Memory Polyurethane[J];Journal of DongHua University;2002年03期

相關(guān)博士學位論文 前1條

1 阮長順;新型骨修復材料可降解哌嗪基聚氨酯脲的研究[D];重慶大學;2011年

相關(guān)碩士學位論文 前1條

1 張曉彥;哌嗪擴鏈的新型形狀記憶聚氨酯脲的研究[D];重慶大學;2012年

，

本文編號：1914872