微米級大孔徑絲素復(fù)合納米纖維支架的制備及性能研究

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本文關(guān)鍵詞：微米級大孔徑絲素復(fù)合納米纖維支架的制備及性能研究　出處：《浙江理工大學》2017年碩士論文　論文類型：學位論文

【摘要】：靜電紡絲納米纖維支架在纖維尺寸和結(jié)構(gòu)上與生物細胞生長環(huán)境的細胞外基質(zhì)(ECM)較相似,因此在皮膚、軟骨、角膜、神經(jīng)等組織工程領(lǐng)域有廣泛的應(yīng)用,但靜電紡納米纖維支架內(nèi)纖維排列緊密、纖維之間的空隙過小,使得細胞難以長入,無法構(gòu)成較厚的細胞組織。本文利用靜電紡絲技術(shù),結(jié)合材料犧牲法、負電壓收集著重研究對納米纖維支架厚度、孔徑和空隙率的影響,制備出接近細胞尺寸的微米級大孔徑納米纖維支架。本文選擇濃度為20wt%的PEG的氯仿溶液作為靜電噴霧溶液,該濃度下的溶液中的PEG大分子鏈處在半稀溶液中度纏結(jié)體系范圍內(nèi),在該纏結(jié)體系內(nèi)獲得靜電噴霧PEG微球的形貌最穩(wěn)定,且可用于靜電噴霧的電噴流率調(diào)節(jié)范圍也比較大,在流率為4 mL/h以下都能收集到形貌穩(wěn)定的PEG微球。結(jié)果表明在條件下可以制備出直徑10微米左右水溶性PEG微球,且在不同的靜電噴霧流率下都可以獲得尺寸、形貌穩(wěn)定的PEG微球。結(jié)合材料犧牲法,運用滾筒接收裝置收集混雜靜電噴霧PEG微球的SF/Gelatin納米纖維復(fù)合支架,調(diào)整靜電噴霧的流率來控制復(fù)合納米纖維支架中PEG微球的含量制備出不同孔徑及孔隙率規(guī)格的復(fù)合納米纖維支架;之后通過水洗去除摻雜在納米纖維支架中水溶性PEG微球,進一步增大復(fù)合納米纖維支架的孔徑及孔隙率;當PEG微球含量較高時,洗去的PEG微球后復(fù)合納米纖維支架平均孔徑可以達到20μm以上,但電紡支架的力學強度會隨著PEG含量的提高而顯著下降。為了提高納米纖維支架的厚度和孔徑,改用自制有機玻璃板結(jié)合金屬銅板收集裝置并連接負電壓電源有效減小靜電紡絲收集的面積,在針頭處連接+15 kV高壓電源并在圓形銅板處連接負高壓電源可以制備出3 mm厚的SF/PCL納米纖維支架;建立坐標系,分析針頭與圓形金屬板中心之間和PMMA平板上的電場分布情況,探索出在接近圓孔收集板處電場強度顯著提高,使纖維受到向外擴散時間和電場力也減少,導(dǎo)致納米纖維更多集中往連接負電壓的圓孔處靠攏;最后利用樣品截面SEM照片分析孔徑,得出超厚納米纖維支架的孔徑隨納米纖維支架厚度增加而變大,當厚度d600μm時,其厚度區(qū)域內(nèi)的納米纖維支架的孔徑可以達到25μm以上。
[Abstract]:Electrostatic spinning nanofiber scaffolds are similar in size and structure to ECM in the living cell environment, and therefore in the skin, cartilage, and cornea. Nerve and other tissue engineering fields have been widely used, but the fibers in the scaffold of electrospun nanofibers are tightly arranged and the gap between the fibers is too small, which makes it difficult for cells to grow into the scaffold. In this paper, the effect of negative voltage collection on the thickness, pore size and porosity of nanofiber scaffolds was studied by using electrospinning technique and material sacrificial method. Micron sized nano-fiber scaffolds of near cell size were prepared. Chloroform solution of PEG with concentration of 20 wt% was selected as electrostatic spray solution in this paper. The PEG macromolecular chains in the solution at this concentration are in the range of degree entanglement in semi-dilute solution, and the morphology of electrostatic sprayed PEG microspheres is the most stable in the entangled system. And the range of EFI rate can be used for electrostatic spray is also relatively large. The PEG microspheres with stable morphology can be obtained when the flow rate is less than 4 mL/h. The results show that the water-soluble PEG microspheres with a diameter of about 10 microns can be prepared under the conditions. PEG microspheres with stable size and morphology can be obtained under different electrostatic spray flow rates. The SF/Gelatin nanofiber composite scaffold with hybrid electrostatic sprayed PEG microspheres was collected by drum receiving device. Adjusting the flow rate of electrostatic spray to control the content of PEG microspheres in composite nanofiber scaffold, the composite nanofiber scaffolds with different pore sizes and porosity specifications were prepared. After that, the water-soluble PEG microspheres doped in the nanofiber scaffold were removed by washing to further increase the pore size and porosity of the composite nanofiber scaffold. When the content of PEG microspheres is high, the average pore size of the composite nanofiber scaffolds after washing PEG microspheres can reach more than 20 渭 m. However, the mechanical strength of electrospun scaffolds will decrease with the increase of PEG content, in order to increase the thickness and pore size of nano-fiber scaffolds. Using self-made plexiglass plate combined with metal copper plate collecting device and connecting negative voltage power supply can effectively reduce the area of electrostatic spinning collection. The 3mm thick SF/PCL nanofiber scaffold can be fabricated by connecting the 15 kV high voltage power supply at the needle and the negative high voltage power supply at the circular copper plate. The electric field distribution between the needle and the center of the circular metal plate and on the PMMA plate was analyzed in the coordinate system, and the electric field intensity was significantly increased near the circular hole collecting plate. The diffusion time and electric field force of the fibers are also reduced, which leads to more concentration of the nanofibers towards the round holes connected with negative voltage. At last, the pore size of ultra-thick nanofiber scaffold was analyzed by SEM photographs of the sample section, and the pore size increased with the increase of the thickness of nano-fiber scaffold, when the thickness of nano-fiber scaffold was 600 渭 m. The pore size of nanofiber scaffold in its thickness region can reach more than 25 渭 m.
【學位授予單位】：浙江理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：R318.08;TQ340.64

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