具有管中管結(jié)構(gòu)復(fù)合神經(jīng)導(dǎo)管的制備及材料性能研究
發(fā)布時(shí)間：2018-07-15 11:55
【摘要】：隨著神經(jīng)損傷發(fā)生率的大幅度上升,神經(jīng)移植已不能很好地滿足需要,新方向的探索變得尤為重要,神經(jīng)導(dǎo)管作為一種新的治療方法應(yīng)運(yùn)而生。神經(jīng)導(dǎo)管組織工程支架可以為神經(jīng)的生長提供良好的微環(huán)境,理想的神經(jīng)導(dǎo)管還能促進(jìn)受損神經(jīng)的愈合或?yàn)樯窠?jīng)的生長提供導(dǎo)向作用。本文設(shè)計(jì)了一種管中管新構(gòu)型的神經(jīng)導(dǎo)管,詳細(xì)討論了各部分材料的基本性能,對管中管結(jié)構(gòu)神經(jīng)導(dǎo)管的可行性進(jìn)行初步探索,期望復(fù)合結(jié)構(gòu)的神經(jīng)導(dǎo)管會對神經(jīng)再生起到積極作用。 通過靜電紡絲法制備得到的納米纖維,由于具有較高的孔隙率、較大的比表面積及高表面能等優(yōu)勢,能夠從納米尺度來模仿天然細(xì)胞外基質(zhì),被廣泛地應(yīng)用于組織工程支架材料、傷口敷料及藥物載體等方面。因此本文首先采用靜電紡絲技術(shù)制備神經(jīng)導(dǎo)管的外管支架,通過旋轉(zhuǎn)接收裝置、優(yōu)化紡絲參數(shù),制備得到仿細(xì)胞外基質(zhì)的有序納米纖維支架,作為細(xì)胞生長的支撐,促進(jìn)細(xì)胞的遷移及增殖。另外,濕法中空纖維成型是一步法連續(xù)制備中空纖維導(dǎo)管的有效途徑,在制備管內(nèi)部纖維導(dǎo)管時(shí)采用濕法紡絲技術(shù)。 本文選用脂肪族聚碳酸丁二脂(PBC)、甲殼素納米晶須(ChW)、高密度殼聚糖(HCS)及表面功能化的多壁碳納米管(f-MWNTs)作為基本支架材料,通過靜電紡絲接收裝置的改進(jìn)、材料組合、表面改性等,系統(tǒng)地研究評價(jià)了這類材料用作神經(jīng)修復(fù)組織工程材料的力學(xué)性能、細(xì)胞相容性及降解性能等。主要研究工作如下： 1.通過靜電紡絲法制備無規(guī)和有序PBC納米纖維,研究了接收線速度對納米纖維基本性能的影響。之后研究了低溫等離子表面改性技術(shù)對纖維表面親水性的影響,并通過等離子改性方法誘導(dǎo)纖維表面接枝明膠,以增強(qiáng)纖維表面的生物相容性。研究表明,PBC可以均勻地溶解于甲酸、DMF、六氟異丙醇及氯仿等有機(jī)溶劑中,但僅溶解于甲酸能夠得到表面光滑、粗細(xì)均勻的納米級纖維；通過轉(zhuǎn)軸法可以成功制備得到PBC有序納米纖維,隨著旋轉(zhuǎn)線速度的增大,纖維的排列有序度、晶區(qū)及分子鏈的取向度、結(jié)晶度以及力學(xué)性能都有所增大。 2.為了進(jìn)一步提高外管有序納米纖維的力學(xué)性能。首先通過酸解法制備得到納米級甲殼素晶須,然后將其與PBC進(jìn)行共混復(fù)合,通過靜電紡絲法制備得到納米級復(fù)合纖維,研究發(fā)現(xiàn)利用酸解法制得的甲殼素晶須的長度范圍為180-680nm,直徑分布范圍為15-30nm,平均長徑比為14.7,且將晶須分散到甲酸中24h后對表面形貌的觀察發(fā)現(xiàn),在短時(shí)間內(nèi)甲酸并不會影響到晶須形貌,為下一步實(shí)驗(yàn)提供了依據(jù)；對將不同含量的晶須添到PBC中制得復(fù)合納米纖維的研究表明,當(dāng)晶須含量為5.0wt%時(shí),制得的納米纖維表面光滑、直徑分布均勻且隨著晶須的加入結(jié)晶度、熱穩(wěn)定性及力學(xué)性能得到顯著提高。之后采用低溫等離子技術(shù)對表面進(jìn)行改性處理并用明膠接枝以賦予纖維表面新的生物相容性,使其親水性得到了很大的提高,且更有利于神經(jīng)細(xì)胞RSC96的黏附與增殖。 3.采用高密度殼聚糖(HCS)來制備導(dǎo)管內(nèi)部的中空纖維。首先研究了HCS質(zhì)量分?jǐn)?shù)以及溫度等對紡絲漿液穩(wěn)定性的影響；而后進(jìn)行濕法紡絲制備了中空纖維,并對HCS中空纖維的化學(xué)結(jié)構(gòu)、晶體結(jié)構(gòu)和熱性能進(jìn)行了研究。結(jié)果表明,HCS的固含量為5wt%時(shí),紡絲過程順利進(jìn)行,擠出的漿液在凝固浴中形成的初生纖維結(jié)構(gòu)均勻,不會出現(xiàn)斷絲情況。紡絲溫度應(yīng)控制在20-30℃；凝固浴濃度為3wt%時(shí)所得的中空纖維熱力學(xué)及結(jié)構(gòu)性能較好。因此,在后續(xù)的實(shí)驗(yàn)研究中,將采用質(zhì)量分?jǐn)?shù)為5wt%HCS紡絲漿液,以質(zhì)量分?jǐn)?shù)為3wt%的NaOH-乙醇溶液作為凝固浴制備中空纖維。 4.采用碳納米管來增強(qiáng)HCS中空纖維的力學(xué)和電學(xué)性能。為了提高碳管在HCS溶液中的分散性及與HCS基體之間的相容性,通過表面沉積交聯(lián)法對碳管進(jìn)行表面修飾得到f-MWNTs。然后與HCS進(jìn)行混合制得復(fù)合中空纖維,并對其性能進(jìn)行了研究分析。研究發(fā)現(xiàn),經(jīng)過表面修飾得到的f-MWNTs的管身變得平直,纏結(jié)狀態(tài)也有所緩解,且在水中的分散性就明顯優(yōu)于MWNTs;對復(fù)合中空纖維的研究發(fā)現(xiàn)當(dāng)f-MWNTs的含量達(dá)到0.5wt%時(shí),f-MWNTs在HCS基體中的分布最為均勻,中空纖維的斷面形貌也最為致密；且復(fù)合纖維的拉伸強(qiáng)度和彈性模量均達(dá)到最大值,分別為9.33MPa和2.34GPa；在含水率相同的條件下,隨著碳管含量的增加復(fù)合纖維的電導(dǎo)率也增加。經(jīng)過等離子預(yù)處理和明膠接枝改性后,復(fù)合膜在各個(gè)壓力下的水通量都有了明顯的提高,且更有利于細(xì)胞的黏附與增殖。 5.管中管結(jié)構(gòu)的神經(jīng)導(dǎo)管外層通過將靜電紡有序納米纖維沿一定直徑的芯棒卷繞成管狀結(jié)構(gòu),內(nèi)部填充中空纖維,得到內(nèi)部通道不同的導(dǎo)管。對導(dǎo)管的壓縮性能的研究表明,5-通道神經(jīng)導(dǎo)管在形變量為25%時(shí),負(fù)荷力高達(dá)201cN,完全能夠滿足神經(jīng)導(dǎo)管徑向支撐力的要求；管中管結(jié)構(gòu)的神經(jīng)導(dǎo)管在受到外界壓力時(shí),形狀發(fā)生變化后能夠自然恢復(fù),即形變后也能承擔(dān)一定的支撐作用,符合神經(jīng)導(dǎo)管力學(xué)性能的要求。 因此本文所制備的管中管復(fù)合型神經(jīng)導(dǎo)管在親水性、降解性及細(xì)胞相容性上都有所提高,同時(shí)具有良好的機(jī)械性能,有望成為新一代的神經(jīng)修復(fù)組織工程支架。
[Abstract]:Neurovascular tissue engineering stent can provide a good microenvironment for the growth of nerve , and the ideal nerve catheter can promote the healing of damaged nerve or provide guidance for the growth of nerve .
The nano - fiber prepared by the electrostatic spinning method has the advantages of high porosity , larger specific surface area and high surface energy and the like , can imitate the natural extracellular matrix from nano - scale , is widely applied to tissue engineering scaffold materials , wound dressings and drug carriers and the like .
In this paper , the mechanical properties , cell compatibility and degradation properties of this kind of materials used as nerve repairing tissue engineering materials were systematically studied by using aliphatic polycarbonate ( PBC ) , chitin nano whisker ( ChW ) , high density chitosan ( HCS ) and surface functionalized multi - walled carbon nanotubes ( f - MWCNTs ) as the basic scaffold materials . The main research work is as follows :
1 . The influence of receiving linear velocity on the basic properties of nanofibers was studied by electrostatic spinning . The effect of low temperature plasma surface modification on fiber surface hydrophilicity was studied . The surface grafting gelatin was induced by plasma modification to enhance the biocompatibility of the fiber surface . The results showed that PBC could be dissolved in formic acid , DMF , hexafluoroisopropanol and chloroform , but only dissolved in formic acid to obtain the nano - fiber with smooth surface and uniform thickness .
By using the rotating shaft method , the PBC ordered nanofibers can be successfully prepared . With the increase of the rotating linear velocity , the arrangement order of the fibers , the orientation degree of the crystal region and the molecular chain , the crystallinity and the mechanical properties are increased .
2 . In order to further improve the mechanical properties of the ordered nano - fibers , the nano - sized chitin whiskers were prepared by an acid hydrolysis method . The nano - scale composite fibers were prepared by electrostatic spinning . The results showed that the length of the chitin whiskers prepared by acid hydrolysis was 180 - 680 nm , the diameter distribution range was 15 - 30 nm , the average length - to - diameter ratio was 14.7 , and the morphology of the whisker was not affected after 24 h in the formic acid .
It is shown that when the whisker content is 5.0 wt % , the surface of the prepared nanofiber is smooth , the diameter distribution is uniform and the crystallinity , the thermal stability and the mechanical property of the whisker are remarkably improved . The surface is modified by low - temperature plasma technology , and the surface is grafted with gelatin to give new biocompatibility to the surface of the fiber , so that the hydrophilicity is greatly improved , and the adhesion and proliferation of the nerve cell RSC96 are more favorable .
3 . High density chitosan ( HCS ) was used to prepare the hollow fiber inside the catheter . The effect of HCS mass fraction and temperature on the stability of spinning slurry was studied .
The hollow fibers were prepared by wet spinning , and the chemical structure , crystal structure and thermal properties of HCS hollow fibers were studied . The results showed that when the solid content of HCS was 5 % by weight , the spinning process proceeded smoothly .
Therefore , in the subsequent experimental study , the hollow fiber was prepared by using an HCS spinning slurry with mass fraction of 5 wt % and a NaOH - ethanol solution with a mass fraction of 3 wt % as a coagulation bath .
4 . Carbon nanotubes were used to enhance the mechanical and electrical properties of HCS hollow fibers . In order to improve the dispersion of carbon nanotubes in HCS solution and compatibility with HCS matrix , the surface modification of carbon nanotubes was carried out by surface deposition crosslinking method .
and the tensile strength and the elastic modulus of the composite fiber reach the maximum value , which is 9.33MPa and 2.34GPa , respectively ;
Under the condition of the same water content , the conductivity of the composite fiber increases with the increase of the content of the carbon tube . After plasma pretreatment and gelatin grafting modification , the water flux of the composite membrane under each pressure is obviously improved , and the cell adhesion and proliferation are more favorable .
5 . The outer layer of the nerve conduit of the tube structure of the tube is wound into a tubular structure along a mandrel with a certain diameter by the electrospun ordered nanofibers , and hollow fibers are filled in the tube to obtain different catheters of the inner channel .
When the nerve conduit in the tube is subjected to external pressure , the shape of the nerve conduit can be restored naturally after the shape is changed , that is , the nerve conduit of the tube structure can bear a certain supporting effect after deformation , and conforms to the requirements of the mechanical property of the nerve catheter .
therefore , the composite nerve conduit in the tube prepared in the present invention has improved hydrophilicity , degradability and cell compatibility , and has good mechanical properties , and is expected to be a new generation of nerve repair tissue engineering scaffold .
【學(xué)位授予單位】：東華大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：R318.08;TB383.1
本文編號：2123990
[Abstract]:Neurovascular tissue engineering stent can provide a good microenvironment for the growth of nerve , and the ideal nerve catheter can promote the healing of damaged nerve or provide guidance for the growth of nerve .
The nano - fiber prepared by the electrostatic spinning method has the advantages of high porosity , larger specific surface area and high surface energy and the like , can imitate the natural extracellular matrix from nano - scale , is widely applied to tissue engineering scaffold materials , wound dressings and drug carriers and the like .
In this paper , the mechanical properties , cell compatibility and degradation properties of this kind of materials used as nerve repairing tissue engineering materials were systematically studied by using aliphatic polycarbonate ( PBC ) , chitin nano whisker ( ChW ) , high density chitosan ( HCS ) and surface functionalized multi - walled carbon nanotubes ( f - MWCNTs ) as the basic scaffold materials . The main research work is as follows :
1 . The influence of receiving linear velocity on the basic properties of nanofibers was studied by electrostatic spinning . The effect of low temperature plasma surface modification on fiber surface hydrophilicity was studied . The surface grafting gelatin was induced by plasma modification to enhance the biocompatibility of the fiber surface . The results showed that PBC could be dissolved in formic acid , DMF , hexafluoroisopropanol and chloroform , but only dissolved in formic acid to obtain the nano - fiber with smooth surface and uniform thickness .
By using the rotating shaft method , the PBC ordered nanofibers can be successfully prepared . With the increase of the rotating linear velocity , the arrangement order of the fibers , the orientation degree of the crystal region and the molecular chain , the crystallinity and the mechanical properties are increased .
2 . In order to further improve the mechanical properties of the ordered nano - fibers , the nano - sized chitin whiskers were prepared by an acid hydrolysis method . The nano - scale composite fibers were prepared by electrostatic spinning . The results showed that the length of the chitin whiskers prepared by acid hydrolysis was 180 - 680 nm , the diameter distribution range was 15 - 30 nm , the average length - to - diameter ratio was 14.7 , and the morphology of the whisker was not affected after 24 h in the formic acid .
It is shown that when the whisker content is 5.0 wt % , the surface of the prepared nanofiber is smooth , the diameter distribution is uniform and the crystallinity , the thermal stability and the mechanical property of the whisker are remarkably improved . The surface is modified by low - temperature plasma technology , and the surface is grafted with gelatin to give new biocompatibility to the surface of the fiber , so that the hydrophilicity is greatly improved , and the adhesion and proliferation of the nerve cell RSC96 are more favorable .
3 . High density chitosan ( HCS ) was used to prepare the hollow fiber inside the catheter . The effect of HCS mass fraction and temperature on the stability of spinning slurry was studied .
The hollow fibers were prepared by wet spinning , and the chemical structure , crystal structure and thermal properties of HCS hollow fibers were studied . The results showed that when the solid content of HCS was 5 % by weight , the spinning process proceeded smoothly .
Therefore , in the subsequent experimental study , the hollow fiber was prepared by using an HCS spinning slurry with mass fraction of 5 wt % and a NaOH - ethanol solution with a mass fraction of 3 wt % as a coagulation bath .
4 . Carbon nanotubes were used to enhance the mechanical and electrical properties of HCS hollow fibers . In order to improve the dispersion of carbon nanotubes in HCS solution and compatibility with HCS matrix , the surface modification of carbon nanotubes was carried out by surface deposition crosslinking method .
and the tensile strength and the elastic modulus of the composite fiber reach the maximum value , which is 9.33MPa and 2.34GPa , respectively ;
Under the condition of the same water content , the conductivity of the composite fiber increases with the increase of the content of the carbon tube . After plasma pretreatment and gelatin grafting modification , the water flux of the composite membrane under each pressure is obviously improved , and the cell adhesion and proliferation are more favorable .
5 . The outer layer of the nerve conduit of the tube structure of the tube is wound into a tubular structure along a mandrel with a certain diameter by the electrospun ordered nanofibers , and hollow fibers are filled in the tube to obtain different catheters of the inner channel .
When the nerve conduit in the tube is subjected to external pressure , the shape of the nerve conduit can be restored naturally after the shape is changed , that is , the nerve conduit of the tube structure can bear a certain supporting effect after deformation , and conforms to the requirements of the mechanical property of the nerve catheter .
therefore , the composite nerve conduit in the tube prepared in the present invention has improved hydrophilicity , degradability and cell compatibility , and has good mechanical properties , and is expected to be a new generation of nerve repair tissue engineering scaffold .
【學(xué)位授予單位】：東華大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：R318.08;TB383.1
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