静电纺丝制备PU/PVDF压电性细胞支架及其应用于创伤愈合领域的研究
|
摘要
研究背景及目的
创伤敷料可以加速创伤愈合。目前已上市或正在研发的敷料根据材质不同大致可分为传统敷料、天然敷料、合成敷料、药物敷料和组织工程敷料等几大类。这些敷料通过不同的机制发挥作用，包括促进细胞迁移、粘附及增殖，抑制细菌生长，促进吸收，保持创面湿润及防止粘连等。研究表明电刺激能够促进多种生长因子的表达和分泌，影响细胞的增殖、分化及再生等功能。电刺激在促进骨折修复及神经再生、治疗骨质疏松、慢性溃疡等领域已有应用，但将其应用于创伤敷料的研发尚未见报道。
许多早先的研究表明压电物质可以用于制备具有电刺激效应的生物材料。压电物质分为无机和有机两大类，前者又分为压电晶体(单晶体)和压电陶瓷(多晶体)，分别以石英晶体和钛酸钡陶瓷为代表；后者又称压电聚合物，以聚偏二氟乙烯(PVDF)为代表。压电物质在生物材料领域的应用，最常见的是压电陶瓷应用于骨组织工程。由于压电陶瓷刚性强弹性弱，不适合应用于血管、神经、筋膜等软组织，因此压电聚合物PVDF近年来受到了很多关注。PVDF是一种多晶型聚合物，常见的晶型主要有α、β及γ三种。通常自由基聚合反应合成的PVDF主要由α晶型构成，不显示压电性。α晶型通过机械拉伸或电场极化可以转变为压电性很强的β晶型。有研究报道，通过静电纺丝可以直接从PVDF溶液得到β晶型的PVDF纤维。
静电纺丝综合了电喷雾和传统干法纺丝的特点，是一种通过强电场力对带静电荷的聚合物溶液或熔体进行拉伸，从而得到微米或纳米级超细纤维的加工工艺。静电纺丝在过滤、个体防护、传感器、自清洁、催化载体、光电磁、复合增强等许多领域都有应用，由于静电纺丝制备的纤维支架具有类似天然细胞外基质结构的特点，其相互连通的孔隙有利于细胞长入，高度的表面积体积比扩大了支架与细胞的接触面积，因此静电纺丝支架在组织工程领域也具有广阔的应用前景。
有研究报道，通过静电纺丝制备的聚偏二氟乙烯-三氟乙烯(PVDF-TrFE)支架具有良好的细胞相容性，在组织工程领域有潜在的应用前景，然而该研究并未涉及压电性对细胞功能的影响。此外，由于PVDF-TrFE氟树脂的力学性能不佳，因此单纯的PVDF-TrFE支架尚不能完全达到创伤敷料的要求。为改善现有研究的不足，本课题拟制备一种可应用于创伤愈合领域的压电性静电纺丝细胞支架，先通过压电系数测定及晶型表征验证支架的压电性，进而通过体内外实验分析探讨支架的压电性对成纤维细胞功能的影响。
研究方法
1、以PU作为改善支架力学性能的成分与PVDF混合，通过静电纺丝制备不同比例成分的PU/PVDF支架。
2、用电子万能试验机测量支架的抗拉强度及断裂伸长率，薄膜压电系数测试仪测量支架的压电系数，选择力学性能和压电性能都较好的一种比例成分的PU/PVDF支架进行后续实验。用扫描电子显微镜观察支架的微观形态，进而测量支架的纤维直径及孔径。通过X射线衍射(XRD)、差示扫描量热(DSC)和傅里叶转换红外光谱(FTIR)分析等方法研究静电纺丝前后PVDF的晶型变化。
3、在支架上培养NIH3T3细胞，通过激光共聚焦显微镜和扫描电子显微镜观察支架表面的细胞形态，通过CCK-8检测比较支架与组织培养聚苯乙烯(即普通细胞培养板或培养瓶的构成材料)的细胞相容性。
4、将支架粘贴在BioFlex Culture Plate孔底的硅胶弹性膜上，利用FX-4000T体外培养细胞加力系统使支架发生形变，从而激发压电性。通过划痕实验、粘附实验、定量PCR和Western blot等方法，研究支架的压电性对迁移、粘附及分泌细胞外基质等成纤维细胞主要功能的影响。
5、将支架植入SD大鼠皮下以验证支架的生物相容性，通过扫描电子显微镜、切片HE染色、激光共聚焦显微镜、流式细胞学检测和力学性能测试等方法，研究支架的压电性对体内成纤维细胞的刺激作用。
实验结果
1、获得理想形态纤维的静电纺丝最佳参数为流速0.8ml/h、电压15kV、接收距离20cm。选择PU/PVDF (1:1)支架进行后续实验，该支架的纤维直径和孔径分别为1.41±0.32μm、11.47±1.14μm。X射线衍射、差示扫描量热和红外光谱分析的结果表明，经过静电纺丝加工，PVDF粉末中的α晶型PVDF已基本上转变为PU/PVDF支架中的β晶型PVDF。
2、激光共聚焦显微镜和扫描电子显微镜观察的结果显示，NIH3T3细胞能在PU/PVDF支架上正常生长和增殖。CCK-8检测的结果表明，PU/PVDF支架的细胞相容性与组织培养聚苯乙烯相当，NIH3T3细胞能在支架上正常增殖。
3、划痕实验、粘附实验、定量PCR和Western blot的结果显示，实验组(压电激发的PU/PVDF支架)细胞层的迁移、粘附及分泌细胞外基质等功能均高于两个对照组(压电激发的PU支架和非压电激发的PU/PVDF支架)，确认了使成纤维细胞功能增强的因素是PU/PVDF支架的压电性而非支架本身的化学成分或压电激发的处理过程。压电激发的PU/PVDF支架由于产生了电刺激效应，因而增强了支架细胞层的功能。
4、扫描电子显微镜、切片HE染色和激光共聚焦显微镜观察的结果显示，颅顶部皮下植入(很少发生形变)的PU/PVDF支架表面细胞的活跃程度与PU支架相当，而背部及腹部皮下植入(经常发生形变)的PU/PVDF支架表面细胞的活跃程度均较PU支架高，确认了使体内成纤维细胞活跃程度增强的因素是PU/PVDF支架的压电性而非支架本身的化学成分或支架的植入部位。植入背部及腹部皮下的PU/PVDF支架会随大鼠的自主活动经常发生形变，从而产生对支架表面细胞(主要是成纤维细胞)有刺激作用的压电效应，进而增强细胞的活跃程度。力学性能测试的结果显示，背部及腹部皮下植入的PU/PVDF支架的细胞复合程度较PU支架高，也说明了PU/PVDF支架对细胞有刺激作用，提高了支架的细胞复合程度。
结论
1、本课题通过静电纺丝制备了不同比例成分的PU/PVDF支架，其中以PU/PVDF(1:1)支架的力学性能和压电性能均适中。该支架在保证压电性能的同时，其力学性能也能达到创伤敷料的要求。
2、对PU/PVDF支架的微观形态进行了观察，测量了支架的纤维直径及孔径。通过晶型表征证实了支架中的PVDF主要由压电性的β晶型构成。
3、通过体外细胞实验验证了PU/PVDF支架的细胞相容性，证实了支架的压电性能够增强成纤维细胞的迁移、粘附及分泌等功能。
4、通过大鼠皮下植入验证了PU/PVDF支架的生物相容性，证实了支架的压电性对体内成纤维细胞的刺激作用。
5、本课题制备的PU/PVDF压电性细胞支架可作为一种能加速创面愈合且成本低廉的新型创伤敷料，在创伤愈合领域具有良好的应用前景。
Background and objectives
Wound healing is a process in which the skin (or other tissues) repairs itself afterinjury. The process can be accelerated and enhanced by the use of wound dressings. Thusfar, different types of wound dressings have been developed based on the specific material,structure and drug that are favourable for wound healing. However, wound dressings basedon electrical stimulation have not been reported yet.
Electrical stimulation influences cell behaviors such as proliferation, differentiationand regeneration. A number of previous studies have shown that piezoelectric materials thatgenerate electrical charges in response to mechanical strain may be used to preparebioactive electrically charged surfaces. Polyvinylidene fluoride (PVDF) is a piezoelectricpolymer that exists in at least three regular phases: α, β and γ phases, etc. Common freeradical polymerisation-processed PVDF is typically in the nonpiezoelectric α phase. Toobtain the piezoelectric β phase, the α phase PVDF needs to be mechanically stretched toorient the molecular chains and then poled under tension. Reports have indicated thatelectrospinning is a simple technique to form the the piezoelectric β phase of PVDF directlyfrom solution.
Electrospinning is an attractive approach for the fabrication of fibers with diametersranging from a few nanometers to several micrometers by creating an electrically chargedjet of polymer solution or melt. This technique has been recently introduced as the mostpromising technique to manufacture scaffolds for tissue engineering applications. Thescaffolds could partially mimic the structure and function of natural extracellular matrices(ECM), thereby enhancing cell adhesion via1) the interconnectivity of voids favourable forcell in-growth and2) the high surface area to volume ratio, which enlarges cell-scaffoldinterface.
A recent study has reported the preparation and in vitro cytocompatibility of poly (vinylidene fluoride-trifluoroethylene)(PVDF-TrFE) electrospun scaffolds and argued thatthere is tremendous potential of the scaffolds for tissue engineering applications. However,the exact piezoelectric effect on the cultured cells was not investigated. In the current study,PU/PVDF scaffolds are prepared by electrospinning. Polyurethane (PU) is a thermoplasticelastomer that has been widely used as prostheses. It is co-electrospun with PVDF becauseof the improved elasticity of the resulting scaffolds. The crystalline phase of PVDF in thescaffolds is characterized, and the piezoelectric effect on fibroblast activities in vitro and invivo are thoroughly investigated with the aim of demonstrating the possible application forwound healing.
Methods
1. PU/PVDF scaffolds of different composition ratios ranging from1:3to3:1(V/V)were prepared by electrospinning.
2. The tensile strength and elongation at break of the scaffolds were tested using anelectronic universal testing machine. The piezoelectric coefficient (d33) of the scaffoldswere tested using Thin/Thick film Piezoelectric Analyzer. Scaffolds that kept a balancebetween mechanical property and piezoelectric property were used for the followingexperiments. The crystalline phase of PVDF in the scaffolds was characterized by X-raydiffraction (XRD), differential scanning calorimetry (DSC) and Fourier transform infraredspectroscopy (FTIR), respectively.
3. NIH3T3cells were cultured on the scaffolds. Cell morphologies on the PU/PVDFscaffolds were observed by laser scanning confocal microscopy (LSCM) and scanningelectron microscopy (SEM). CCK-8assays were performed to compare thecytocompatibility of the scaffolds with that of the tissue culture polystyrene (TCPS).
4. To excite piezoelectricity, BioFlex Culture Plates were used with FX-4000TFlexercell tension plus system. The scaffolds were stuck to the flexible silicone bottom ofthe culture plates. Pressure applied to the silicone membrane was then transmitted to thescaffolds, thereby exciting their piezoelectricity. Wound-healing assay, cell-adhesion assay,quantitative RT-PCR and Western blot analyses were performed to investigate piezoelectriceffect of the scaffolds on fibroblast activities.
5. The scaffolds were subcutaneously implanted in Sprague-Dawley (SD) rats to verifytheir biocompatibility. SEM, HE staining, LSCM, flow cytometry (FCM) and mechanical testing were performed to investigate the piezoelectric effect of the scaffolds on fibrosis invivo.
Results
1. The parameters for bead-free scaffolds produced from the PU/PVDF solutions wereas follows: flow rate0.8ml/h, applied voltage15kV and collecting distance20cm. ThePU/PVDF (1:1) scaffolds were used for the following experiments. The mean fiberdiameter and pore size of the scaffolds were1.41±0.32μm and11.47±1.14μm, respectively.XRD, DSC and FTIR analyses had revealed that the electrospinning process had altered thePVDF crystalline phase from the α phase to the β phase.
2. SEM and LSCM revealed that NIH3T3cells grew and proliferated normally on thePU/PVDF scaffolds. CCK-8assays revealed that the cytocompatibility of the scaffolds wascomparable to that of the TCPS.
3. Wound-healing assay, cell-adhesion assay, quantitative RT-PCR and Western blotanalyses revealed that the fibroblasts cultured on the piezoelectric-excited PU/PVDFscaffolds showed enhanced migration, adhesion and secretion. The enhanced cell functionswere due to the piezoelectric effect rather than the scaffolds composition or thepiezoelectric excitation process. Piezoelectric excitation of the PU/PVDF scaffolds causedthe electrical stimulation, which then enhanced the the cell functions.
4. The cells on the implanted scaffolds were mainly fibroblasts. SEM, HE staining andLSCM revealed that the cell activites of the PU/PVDF scaffolds and the PU scaffoldsimplanted in the vertex were almost the same, whereas the cell activites of the PU/PVDFscaffolds were higher than those of the PU scaffolds implanted in the back and abdomen.The enhanced cell activities of the PU/PVDF scaffolds implanted in the back and abdomenwere due to the piezoelectric effect, which was caused by random animal movementsfollowed by mechanical deformation of the scaffolds. Mechanical testing revealed that thefibrosis level of the PU/PVDF scaffolds were higher than that of the PU scaffolds implantedin the back and abdomen. This also indicated that the PU/PVDF scaffolds stimulated cellsand thus increased the fibrosis level.
Conclusions
1. PU/PVDF scaffolds of different composition ratios were prepared byelectrospinning, among which PU/PVDF (1:1) scaffolds kept a balance between mechanical property and piezoelectric property.
2. The micromorphology of the PU/PVDF scaffolds was observed, followed bymeasurement of the fiber diameter and pore size of the scaffolds. Crystalline phasecharacterization confirmed that the PVDF in the scaffolds was mainly in the piezoelectric βphase.
3. The fibroblasts cultured on the PU/PVDF scaffolds showed normal morphology andproliferation. The fibroblasts cultured on the piezoelectric-excited scaffolds showedenhanced migration, adhesion and secretion.
4. The cell activities of the PU/PVDF scaffolds subcutaneously implanted in SD ratswere enhanced due to the piezoelectrical stimulation, which was caused by random animalmovements followed by mechanical deformation of the scaffolds.
5. The scaffolds are potential candidates for wound healing applications.
创伤敷料可以加速创伤愈合。目前已上市或正在研发的敷料根据材质不同大致可分为传统敷料、天然敷料、合成敷料、药物敷料和组织工程敷料等几大类。这些敷料通过不同的机制发挥作用，包括促进细胞迁移、粘附及增殖，抑制细菌生长，促进吸收，保持创面湿润及防止粘连等。研究表明电刺激能够促进多种生长因子的表达和分泌，影响细胞的增殖、分化及再生等功能。电刺激在促进骨折修复及神经再生、治疗骨质疏松、慢性溃疡等领域已有应用，但将其应用于创伤敷料的研发尚未见报道。
许多早先的研究表明压电物质可以用于制备具有电刺激效应的生物材料。压电物质分为无机和有机两大类，前者又分为压电晶体(单晶体)和压电陶瓷(多晶体)，分别以石英晶体和钛酸钡陶瓷为代表；后者又称压电聚合物，以聚偏二氟乙烯(PVDF)为代表。压电物质在生物材料领域的应用，最常见的是压电陶瓷应用于骨组织工程。由于压电陶瓷刚性强弹性弱，不适合应用于血管、神经、筋膜等软组织，因此压电聚合物PVDF近年来受到了很多关注。PVDF是一种多晶型聚合物，常见的晶型主要有α、β及γ三种。通常自由基聚合反应合成的PVDF主要由α晶型构成，不显示压电性。α晶型通过机械拉伸或电场极化可以转变为压电性很强的β晶型。有研究报道，通过静电纺丝可以直接从PVDF溶液得到β晶型的PVDF纤维。
静电纺丝综合了电喷雾和传统干法纺丝的特点，是一种通过强电场力对带静电荷的聚合物溶液或熔体进行拉伸，从而得到微米或纳米级超细纤维的加工工艺。静电纺丝在过滤、个体防护、传感器、自清洁、催化载体、光电磁、复合增强等许多领域都有应用，由于静电纺丝制备的纤维支架具有类似天然细胞外基质结构的特点，其相互连通的孔隙有利于细胞长入，高度的表面积体积比扩大了支架与细胞的接触面积，因此静电纺丝支架在组织工程领域也具有广阔的应用前景。
有研究报道，通过静电纺丝制备的聚偏二氟乙烯-三氟乙烯(PVDF-TrFE)支架具有良好的细胞相容性，在组织工程领域有潜在的应用前景，然而该研究并未涉及压电性对细胞功能的影响。此外，由于PVDF-TrFE氟树脂的力学性能不佳，因此单纯的PVDF-TrFE支架尚不能完全达到创伤敷料的要求。为改善现有研究的不足，本课题拟制备一种可应用于创伤愈合领域的压电性静电纺丝细胞支架，先通过压电系数测定及晶型表征验证支架的压电性，进而通过体内外实验分析探讨支架的压电性对成纤维细胞功能的影响。
研究方法
1、以PU作为改善支架力学性能的成分与PVDF混合，通过静电纺丝制备不同比例成分的PU/PVDF支架。
2、用电子万能试验机测量支架的抗拉强度及断裂伸长率，薄膜压电系数测试仪测量支架的压电系数，选择力学性能和压电性能都较好的一种比例成分的PU/PVDF支架进行后续实验。用扫描电子显微镜观察支架的微观形态，进而测量支架的纤维直径及孔径。通过X射线衍射(XRD)、差示扫描量热(DSC)和傅里叶转换红外光谱(FTIR)分析等方法研究静电纺丝前后PVDF的晶型变化。
3、在支架上培养NIH3T3细胞，通过激光共聚焦显微镜和扫描电子显微镜观察支架表面的细胞形态，通过CCK-8检测比较支架与组织培养聚苯乙烯(即普通细胞培养板或培养瓶的构成材料)的细胞相容性。
4、将支架粘贴在BioFlex Culture Plate孔底的硅胶弹性膜上，利用FX-4000T体外培养细胞加力系统使支架发生形变，从而激发压电性。通过划痕实验、粘附实验、定量PCR和Western blot等方法，研究支架的压电性对迁移、粘附及分泌细胞外基质等成纤维细胞主要功能的影响。
5、将支架植入SD大鼠皮下以验证支架的生物相容性，通过扫描电子显微镜、切片HE染色、激光共聚焦显微镜、流式细胞学检测和力学性能测试等方法，研究支架的压电性对体内成纤维细胞的刺激作用。
实验结果
1、获得理想形态纤维的静电纺丝最佳参数为流速0.8ml/h、电压15kV、接收距离20cm。选择PU/PVDF (1:1)支架进行后续实验，该支架的纤维直径和孔径分别为1.41±0.32μm、11.47±1.14μm。X射线衍射、差示扫描量热和红外光谱分析的结果表明，经过静电纺丝加工，PVDF粉末中的α晶型PVDF已基本上转变为PU/PVDF支架中的β晶型PVDF。
2、激光共聚焦显微镜和扫描电子显微镜观察的结果显示，NIH3T3细胞能在PU/PVDF支架上正常生长和增殖。CCK-8检测的结果表明，PU/PVDF支架的细胞相容性与组织培养聚苯乙烯相当，NIH3T3细胞能在支架上正常增殖。
3、划痕实验、粘附实验、定量PCR和Western blot的结果显示，实验组(压电激发的PU/PVDF支架)细胞层的迁移、粘附及分泌细胞外基质等功能均高于两个对照组(压电激发的PU支架和非压电激发的PU/PVDF支架)，确认了使成纤维细胞功能增强的因素是PU/PVDF支架的压电性而非支架本身的化学成分或压电激发的处理过程。压电激发的PU/PVDF支架由于产生了电刺激效应，因而增强了支架细胞层的功能。
4、扫描电子显微镜、切片HE染色和激光共聚焦显微镜观察的结果显示，颅顶部皮下植入(很少发生形变)的PU/PVDF支架表面细胞的活跃程度与PU支架相当，而背部及腹部皮下植入(经常发生形变)的PU/PVDF支架表面细胞的活跃程度均较PU支架高，确认了使体内成纤维细胞活跃程度增强的因素是PU/PVDF支架的压电性而非支架本身的化学成分或支架的植入部位。植入背部及腹部皮下的PU/PVDF支架会随大鼠的自主活动经常发生形变，从而产生对支架表面细胞(主要是成纤维细胞)有刺激作用的压电效应，进而增强细胞的活跃程度。力学性能测试的结果显示，背部及腹部皮下植入的PU/PVDF支架的细胞复合程度较PU支架高，也说明了PU/PVDF支架对细胞有刺激作用，提高了支架的细胞复合程度。
结论
1、本课题通过静电纺丝制备了不同比例成分的PU/PVDF支架，其中以PU/PVDF(1:1)支架的力学性能和压电性能均适中。该支架在保证压电性能的同时，其力学性能也能达到创伤敷料的要求。
2、对PU/PVDF支架的微观形态进行了观察，测量了支架的纤维直径及孔径。通过晶型表征证实了支架中的PVDF主要由压电性的β晶型构成。
3、通过体外细胞实验验证了PU/PVDF支架的细胞相容性，证实了支架的压电性能够增强成纤维细胞的迁移、粘附及分泌等功能。
4、通过大鼠皮下植入验证了PU/PVDF支架的生物相容性，证实了支架的压电性对体内成纤维细胞的刺激作用。
5、本课题制备的PU/PVDF压电性细胞支架可作为一种能加速创面愈合且成本低廉的新型创伤敷料，在创伤愈合领域具有良好的应用前景。
Background and objectives
Wound healing is a process in which the skin (or other tissues) repairs itself afterinjury. The process can be accelerated and enhanced by the use of wound dressings. Thusfar, different types of wound dressings have been developed based on the specific material,structure and drug that are favourable for wound healing. However, wound dressings basedon electrical stimulation have not been reported yet.
Electrical stimulation influences cell behaviors such as proliferation, differentiationand regeneration. A number of previous studies have shown that piezoelectric materials thatgenerate electrical charges in response to mechanical strain may be used to preparebioactive electrically charged surfaces. Polyvinylidene fluoride (PVDF) is a piezoelectricpolymer that exists in at least three regular phases: α, β and γ phases, etc. Common freeradical polymerisation-processed PVDF is typically in the nonpiezoelectric α phase. Toobtain the piezoelectric β phase, the α phase PVDF needs to be mechanically stretched toorient the molecular chains and then poled under tension. Reports have indicated thatelectrospinning is a simple technique to form the the piezoelectric β phase of PVDF directlyfrom solution.
Electrospinning is an attractive approach for the fabrication of fibers with diametersranging from a few nanometers to several micrometers by creating an electrically chargedjet of polymer solution or melt. This technique has been recently introduced as the mostpromising technique to manufacture scaffolds for tissue engineering applications. Thescaffolds could partially mimic the structure and function of natural extracellular matrices(ECM), thereby enhancing cell adhesion via1) the interconnectivity of voids favourable forcell in-growth and2) the high surface area to volume ratio, which enlarges cell-scaffoldinterface.
A recent study has reported the preparation and in vitro cytocompatibility of poly (vinylidene fluoride-trifluoroethylene)(PVDF-TrFE) electrospun scaffolds and argued thatthere is tremendous potential of the scaffolds for tissue engineering applications. However,the exact piezoelectric effect on the cultured cells was not investigated. In the current study,PU/PVDF scaffolds are prepared by electrospinning. Polyurethane (PU) is a thermoplasticelastomer that has been widely used as prostheses. It is co-electrospun with PVDF becauseof the improved elasticity of the resulting scaffolds. The crystalline phase of PVDF in thescaffolds is characterized, and the piezoelectric effect on fibroblast activities in vitro and invivo are thoroughly investigated with the aim of demonstrating the possible application forwound healing.
Methods
1. PU/PVDF scaffolds of different composition ratios ranging from1:3to3:1(V/V)were prepared by electrospinning.
2. The tensile strength and elongation at break of the scaffolds were tested using anelectronic universal testing machine. The piezoelectric coefficient (d33) of the scaffoldswere tested using Thin/Thick film Piezoelectric Analyzer. Scaffolds that kept a balancebetween mechanical property and piezoelectric property were used for the followingexperiments. The crystalline phase of PVDF in the scaffolds was characterized by X-raydiffraction (XRD), differential scanning calorimetry (DSC) and Fourier transform infraredspectroscopy (FTIR), respectively.
3. NIH3T3cells were cultured on the scaffolds. Cell morphologies on the PU/PVDFscaffolds were observed by laser scanning confocal microscopy (LSCM) and scanningelectron microscopy (SEM). CCK-8assays were performed to compare thecytocompatibility of the scaffolds with that of the tissue culture polystyrene (TCPS).
4. To excite piezoelectricity, BioFlex Culture Plates were used with FX-4000TFlexercell tension plus system. The scaffolds were stuck to the flexible silicone bottom ofthe culture plates. Pressure applied to the silicone membrane was then transmitted to thescaffolds, thereby exciting their piezoelectricity. Wound-healing assay, cell-adhesion assay,quantitative RT-PCR and Western blot analyses were performed to investigate piezoelectriceffect of the scaffolds on fibroblast activities.
5. The scaffolds were subcutaneously implanted in Sprague-Dawley (SD) rats to verifytheir biocompatibility. SEM, HE staining, LSCM, flow cytometry (FCM) and mechanical testing were performed to investigate the piezoelectric effect of the scaffolds on fibrosis invivo.
Results
1. The parameters for bead-free scaffolds produced from the PU/PVDF solutions wereas follows: flow rate0.8ml/h, applied voltage15kV and collecting distance20cm. ThePU/PVDF (1:1) scaffolds were used for the following experiments. The mean fiberdiameter and pore size of the scaffolds were1.41±0.32μm and11.47±1.14μm, respectively.XRD, DSC and FTIR analyses had revealed that the electrospinning process had altered thePVDF crystalline phase from the α phase to the β phase.
2. SEM and LSCM revealed that NIH3T3cells grew and proliferated normally on thePU/PVDF scaffolds. CCK-8assays revealed that the cytocompatibility of the scaffolds wascomparable to that of the TCPS.
3. Wound-healing assay, cell-adhesion assay, quantitative RT-PCR and Western blotanalyses revealed that the fibroblasts cultured on the piezoelectric-excited PU/PVDFscaffolds showed enhanced migration, adhesion and secretion. The enhanced cell functionswere due to the piezoelectric effect rather than the scaffolds composition or thepiezoelectric excitation process. Piezoelectric excitation of the PU/PVDF scaffolds causedthe electrical stimulation, which then enhanced the the cell functions.
4. The cells on the implanted scaffolds were mainly fibroblasts. SEM, HE staining andLSCM revealed that the cell activites of the PU/PVDF scaffolds and the PU scaffoldsimplanted in the vertex were almost the same, whereas the cell activites of the PU/PVDFscaffolds were higher than those of the PU scaffolds implanted in the back and abdomen.The enhanced cell activities of the PU/PVDF scaffolds implanted in the back and abdomenwere due to the piezoelectric effect, which was caused by random animal movementsfollowed by mechanical deformation of the scaffolds. Mechanical testing revealed that thefibrosis level of the PU/PVDF scaffolds were higher than that of the PU scaffolds implantedin the back and abdomen. This also indicated that the PU/PVDF scaffolds stimulated cellsand thus increased the fibrosis level.
Conclusions
1. PU/PVDF scaffolds of different composition ratios were prepared byelectrospinning, among which PU/PVDF (1:1) scaffolds kept a balance between mechanical property and piezoelectric property.
2. The micromorphology of the PU/PVDF scaffolds was observed, followed bymeasurement of the fiber diameter and pore size of the scaffolds. Crystalline phasecharacterization confirmed that the PVDF in the scaffolds was mainly in the piezoelectric βphase.
3. The fibroblasts cultured on the PU/PVDF scaffolds showed normal morphology andproliferation. The fibroblasts cultured on the piezoelectric-excited scaffolds showedenhanced migration, adhesion and secretion.
4. The cell activities of the PU/PVDF scaffolds subcutaneously implanted in SD ratswere enhanced due to the piezoelectrical stimulation, which was caused by random animalmovements followed by mechanical deformation of the scaffolds.
5. The scaffolds are potential candidates for wound healing applications.
引文
1.程玲,高勇,周静,徐玉茵,张娟丽.医用敷料的分类及特点.中国医疗设备2011;26(5):99-101.
2.熊兰,漆洪波,姚陈果,米彦,王士彬.电刺激促进创伤修复的研究进展.国外医学生物医学工程分册2005;28(3):184-7.
3.宋亚文,谢利民.电刺激促进骨折愈合的历史和现状.中国骨伤2003;16(12):764-6.
4.张立宁王兴林.电刺激对周围神经再生的影响.中国康复理论与实践2006;12(7):588-90.
5.谢肇,李起鸿.低频脉冲电磁场治疗绝经后骨质疏松的机制.中国临床康复2003;7(9):1419-21.
6. Peters EJ, Lavery LA, Armstrong DG, Fleischli JG. Electric stimulation as an adjunct toheal diabetic foot ulcers: a randomized clinical trial. Arch Phys Med Rehabil,2001;82(6):721-5
7. Li Z, Qu Y, Zhang X, Yang B. Bioactive nano-titania ceramics with biomechanicalcompatibility prepared by doping with piezoelectric BaTiO3. Acta Biomater2009;5:2189-95.
8. Bouaziz A, Richert A, Caprani A. Vascular endothelial cell responses to differentelectrically charged poly(vinylidene fluoride) supports under static and oscillating flowconditions. Biomaterials1997;18:107-12.
9. Feng J, Yuan H, Zhang X. Promotion of osteogenesis by a piezoelectric biologicalceramic. Biomaterials1997;18:1531-4.
10. Valentini RF, Vargo TG, Gardella JA, Aebischer P. Electrically charged polymericsubstrates enhance nerve fiber outgrowth in vitro. Biomaterials1992;13:183-90.
11. Fine EG, Valentini RF, Bellamkonda R, Aebischer P. Improved nerve regenerationthrough piezoelectric vinylidenefluoride-trifluoroethylene copolymer guidancechannels. Biomaterials1991;12:775-80.
12.李争彩,林书玉.聚偏氟乙烯的性能以及和压电陶瓷的比较.菏泽学院学报2007;29(2):51-4.
13.张军英,李新开,王清海,冀克俭.聚偏氟乙烯的晶体结构及应用.工程塑料应用2008;36(12):79-81.
14.杜春慧,操建华,左丹英,朱宝库,徐又一.聚偏氟乙烯的多晶型及结晶行为的研究进展.功能材料2004;35:3325-9.
15. Andrew JS, Mack JJ, Clarke DR. Electrospinning of polyvinylidene difluoride-basednanocomposite fibers. J Mater Res2008;23:105-14.
16. Ren X, Dzenis Y. Novel continuous poly(vinylidene fluoride) nanofibers. Mater ResSoc Symp Proc.2006;920:55-62.
17. Zhao Z, Li J, Yuan X, Li X, Zhang Y, Sheng J. Preparation and properties ofelectrospun poly(vinylidene fluoride) membranes. J Appl Polym Sci2005;97:466-74.
18. Koombhongse S, Liu W, Reneker DH. Flat polymer ribbons and other shapes byelectrospinning. J Polym Sci Pol Phys2001;39:2598-606.
19.薛聪,胡影影,黄争鸣.静电纺丝原理研究进展.高分子通报2009;(6):38-47.
20.佟艳斌.静电纺丝技术研究及纳米纤维的应用前景.内蒙古民族大学学报2008;14(4):18-20.
21.王兴雪,王海涛,钟伟,杜强,许元泽.静电纺丝纳米纤维的方法与应用现状.非织造布2007;15(2):14-20.
22.王艳春,逯春民.静电纺丝纳米纤维在特殊领域的研究现状和应用.高科技纤维与应用2006;31(1):45-8.
23.吴卫星,段斌,袁晓燕,姚康德.静电纺丝制备聚合物超细纤维的研究及应用.材料导报2005;19(2):72-5.
24. Sill TJ, Von Recum HA. Electrospinning: Applications in drug delivery and tissueengineering. Biomaterials2008;29:1989-2006.
25. Weber N, Lee YS, Shanmugasundaram S, Jaffe M, Arinzeh TL. Characterization and invitro cytocompatibility of piezoelectric electrospun scaffolds. Acta Biomater2010;6:3550-6.
1.刘太奇,许远秦,操彬彬,陈曦.熔体静电纺丝及其装置的研究进展.新技术新工艺2009;(12):93-6.
2.李珍,王军.静电纺丝可纺性影响因素的研究成果.合成纤维2008;(9):6-11.
3.刘芸,戴礼兴.静电纺丝纤维形态及其主要影响因素.合成技术及应用2005;20(1):25-9.
4.于才渊,于春健,朱琳.静电雾化的理论研究及技术应用的进展.干燥技术与设备2003;(1):12-4.
5. Andrew JS, Clarke DR. Effect of electrospinning on the ferroelectric phase content ofpolyvinylidene difluoride fibers. Langmuir2008;24:670-2.
6. Fong H, Chun I, Reneker DH. Beaded nanofibers formed during electrospinning.Polymer1999;40:4585-92.
7.齐中华，俞昊，张瑜，陈彦模.三氯甲烷/乙醇混合溶剂对聚乳酸电纺成形影响的研究.合成纤维2009;(3):40-4.
1. Hattori T, Ohigashi H, Hikosaka M. The crystallization behaviour and phase diagram ofextended-chain crystals of poly(vinylidene fluoride) under high pressure. Polymer1996;37:85-91.
2. Bormashenko Y, Pogreb R, Stanevsky O, Bormashenko E. Vibrational spectrum ofPVDF and its interpretation. Polym Test2004;23:791-6.
3. Salimi A, Yousefi AA. Analysis Method FTIR studies of β-phase crystal formation instretched PVDF films. Polym Test2003;22:699-704.
4. Andrew JS, Clarke DR. Effect of electrospinning on the ferroelectric phase content ofpolyvinylidene difluoride fibers. Langmuir2008;24:670-2.
5. Neidh fer M, Beaume F, Ibos L, Bernèsc A. Lacabannec C. Structural evolution ofPVDF during storage or annealing. Polymer2004;45:1679-88.
6. Laroche G, Marois Y, Guidoin R, King MW, Martin L, How T, Douville Y.Polyvinylidene fluoride (PVDF) as a biomaterial: From polymeric raw material tomonofilament vascular suture. J Biomed Mater Res1995;29:1525-36.
7. Sencadas V, Lanceros-Méndez S, Mano JF. Characterization of poled and non-poledβ-PVDF films using thermal analysis techniques. Thermochim Acta2004;424:201-7.
8. Jungnickel BJ. Poly (vinylidene fluoride)(overview) in: J.C. Salamone (Ed), PolymericMaterials Handbook. CRC Press Inc, NewYork1999;p.7115-22.
1.秦全红.成纤维细胞在皮肤创伤愈合中的作用及其调控.国外医学·创伤与外科基本问题分册2000;21(1):33-8.
2.宋少岩,刘志成.聚乳酸生物材料灭菌方法的研究.中国医疗器械信息2009;15(9):28-30.
3. Weber N, Lee YS, Shanmugasundaram S, Jaffe M, Arinzeh TL. Characterization and invitro cytocompatibility of piezoelectric electrospun scaffolds. Acta Biomater2010;6:3550-6.
1. Zhang J, Wang JH. Mechanobiological response of tendon stem cells: implications oftendon homeostasis and pathogenesis of tendinopathy. J Orthop Res2010;28(5):639-43.
2. Hao Y, Xu C, Sun SY, Zhang FQ. Cyclic stretching force induces apoptosis in humanperiodontal ligament cells via caspase-9. Arch Oral Biol2009;54:864-70.
3. Wescott DC, Pinkerton MN, Gaffey BJ, Beggs KT, Milne TJ, Meikle MC. OsteogenicGene Expression by Human Periodontal Ligament Cells under Cyclic Tension. J DentRes2007;86(12):1212-6.
4. Tang L, Lin Z, Li YM. Effects of different magnitudes of mechanical strain onOsteoblasts in vitro. Biochem Biophys Res Commun2006;344(1):122-8.
5. Yang YQ, Li XT, Rabie AB, Fu MK, Zhang D. Human periodontal ligament cellsexpress osteoblastic phenotypes under intermittent force loading in vitro. Front Biosci2006;11:776-81.
6. Kanno T, Takahashi T, Ariyoshi W. Tensile Mechanical Strain Up-Regulates Runx2andOsteogenic Factor Expression in Human Periosteal Cells: Implications for DistractionOsteogenesis. J Oral Maxil Surg2005;63:499-504.
7.沈敏,田学隆,张平意,李烽.基于直流电刺激的细胞生长培养系统的研制.医疗卫生装备2005;26(5):19-20.
1. Zeleny J. The electrical discharge from liquid points, and a hydrostatic method ofmeasuring the electric intensity at their surfaces. Phys Rev1914;3:69-91.
2. Formhals A. Process and apparatus for preparing artificial threads. US Patent No.1975504,1934.
3. Vonnegut B, Newbauer RL. Production of monodisperse liquid particles by electricalatomization. J Colloid Sci1952;7:616-22.
4. Drozin VG. The electrical dispersion of liquids as aerosols. J Colloid Sci1955;10:158-64.
5. Simons HL. Process and Apparatus for Producing Patterned Nonwoven Fabrics. USPatent3280229,1966.
6. Baumgarten PK. Electrostatic spinning of acrylic microfibers. J Colloid Interface Sci1971;36:71-9.
7. Ramakrishna S, Fujihara K, Teo WE, Yong T, Ma Z, Ramaseshan R. Electrospunnanofibers: solving global issues. Mater Today2006;9:40-50.
8. Kidoaki S, Kwon IK, Matsuda T. Mesoscopic spatial designs of nano and microfibermeshes for tissue-engineering matrix and scaffold based on newly devisedmultilayering and mixing electrospinning techniques. Biomaterials2005;26:37-46.
9. Stankus JJ, Guan J, Fujimoto K, Wagner WR. Microintegrating smooth muscle cellsinto a biodegradable, elastomeric fiber matrix. Biomaterials2006;27:735-44.
10. Taylor GI. Electrically Driven Jets. Proc R Soc Lond, A Math Phys Sci,(1934-1990),1969;313,453-75.
11. Andrew JS, Clarke DR. Effect of electrospinning on the ferroelectric phase content ofpolyvinylidene difluoride fibers. Langmuir2008;24:670-2.
12. Chong EJ, Phan TT, Lim IJ, Zhang YZ, Bay BH, Ramakrishna S, et al. Evaluation ofelectrospun PCL/gelatin nanofibrous scaffold forwound healing and layered dermalreconstitution. Acta Mater2007;3:321–30.
13. Li D, Xia Y. Electrospinning of nanofibers: reinventing the wheel. Adv Mater2004;16:1151–70.
14. Dalton PD, Calvet JL, Mourran A, Klee D, M ller M. Melt electrospinning ofpoly(ethylene glycol-block-ε-caprolactone). Biotechnol J2006;1:998-1006.
15. Kim JS, Lee DS. Thermal properties of electrospun polyesters. Polym J2000;32:616–8.
16. Chun I, Reneker DH, Fong H, Fang X, Deitzel J, Tan NB, et al. Carbon nanofibers frompolyacrylonitrile and mesophase pitch. J Adv Mater1999;31:36–41.
17. Zhou H, Green TB, Joo YL. The thermal effects on electrospinning of polylactic acidmelts. Polymer2006;47:7497–505.
18. Zhmayev E, Zhou H, Joo YL. Modeling of non-isothermal polymer jets in meltelectrospinning. J Non-Newtonian Fluid Mech2008;153:95-108.
19. Pierschbacher MD, Ruoslahti E. Cell attachment activity of fibronectin can beduplicated by small synthetic fragments of the molecule. Nature1984;309:30-3.
20. Zeugolis DI, Khew ST, Yew ESY, Ekaputra AK, Tong YW, Yung LYL, et al.Electro-spinning of pure collagen nano-fibres–just an expensive way to make gelatin?Biomaterials2008;29:2293-305.
21. Matthews JA, Wnek GE, Simpson DG, Bowlin GL. Electrospinning of collagennanofibers. Biomacromolecules2002;3:232-8.
22. Rho KS, Jeong L, Lee G, Seo BM, Park YJ, Hong SD, et al. Electrospinning of collagennanofibers: effects on the behavior of normal human keratinocytes and early-stagewound healing. Biomaterials2006;27:1452-61.
23. Zhang Y, Ouyang H, Lim CT, Ramakrishna S, Huang ZM. Electrospinning of gelatinfibers and gelatin/PCL composite fibrous scaffolds. J Biomed Mater Res B ApplBiomater2005;72:156-65.
24. Kwon IK, Matsuda T. Co-electrospun nanofiber fabrics of poly (l-lactide-co-ε-caprolactone) with type I collagen or heparin. Biomacromolecules2005;6:2096-105.
25. Zhong S, Teo WE, Zhu X, Beuerman R, Ramakrishna S, Yung LY. Formation ofcollagen-glycosaminoglycan blended nanofibrous scaffolds and their biologicalproperties. Biomacromolecules2005;6:2998-3004.
26. Hong DP, Hoshino M, Kuboi R, Goto Y. Clustering of fluorine-substituted alcohols as afactor responsible for their marked effects on proteins and peptides. J Am Chem Soc1999;121:8427-33.
27. Cort JR, Andersen NH. Formation of a molten-globule-like state of myoglobin inaqueous hexafluoroisopropanol. Biochem Biophys Res Commun1997;233:687-91.
28. Kundu A, Kishore N.1,1,1,3,3,3-Hexafluoroisopropanol induced thermal unfolding andmolten globule state of bovine alpha-lactalbumin: calorimetric and spectroscopicstudies. Biopolymers2004;73:405-20.
29. Wang M, Hsieh AJ, Rutledge GC. Electrospinning of poly (MMA-co-MAA)copolymers and their layered silicate nanocomposites for improved thermal properties.Polymer2005;46:3407-18.
30. Kenawy ER, Bowlin GL, Mansfield K, Layman J, Simpson DG, Sanders EH, et al.Release of tetracycline hydrochloride from electrospun poly (ethylene-co-vinylacetate,poly (lactic acid), and a blend. J Control Release2002;81:57-64.
31. Saito N, Okada T, Horiuchi H, Murakami N, Takahashi J, Nawata M, et al.Biodegradable polymer as a cytokine delivery system for inducing bone formation. NatBiotechnol2001;19:332-5.
32. Langer R, Vacanti JP. Tissue Engineering. Science1993;260:920-6.
33. Nerem RM, Sambanis A. Tissue engineering: from biology to biological substitutes.Tissue Eng1995;1:3-13.
34. Hubbell JA. Biomaterials in tissue engineering. Biotechnology1995;13:565-76.
35. Friess W. Collagen–biomaterial for drug delivery. Eur J Pharm Biopharm1998;45:113-36.
36. He W, Horn SW, Hussain MD. Improved bioavailability of orally administeredmifepristone from PLGA nanoparticles. Int J Pharm2007;334:173-8.
37. Li WJ, Laurencin CT, Caterson EJ, Tuan RS, Ko FK. Electrospun nanofibrous structure:a novel scaffold for tissue engineering. J Biomed Mater Res2002;60:613-21.
38. Li C, Vepari C, Jin HJ, Kim HJ, Kaplan DL. Electrospun silk-BMP-2scaffolds for bonetissue engineering. Biomaterials2006;27:3115-24.
39. Li M, Mondrinos MJ, Gandhi MR, Ko FK, Weiss AS, Lelkes PI. Electrospun proteinfibers as matrices for tissue engineering. Biomaterials2005;26:5999-6008.
40. Yoshimoto H, Shin YM, Terai H, Vacanti JP. A biodegradable nanofiber scaffold byelectrospinning and its potential for bone tissue engineering. Biomaterials2003;24:2077-82.
41. Tuan RS, Boland G, Tuli R. Adult mesenchymal stem cells and cell-based tissueengineering. Arthritis Res Ther2003;5:32-45.
42. Jin HJ, Chen J, Karageorgiou V, Altman GH, Kaplan DL. Human bone marrow stromalcell responses to electrospun silk fibroin mats. Biomaterials2004;25:1039-47.
43. Ki CS, Kim JW, Hyun JH, Lee KH, Hattori M, Rah DK, et al. Electrospun threedimensional silk fibroin nanofibrous scaffold. J Appl Polym Sci2007;106:3922-8.
44. Thomas S. Wound management and dressings. Pharm Presse1990;1:37-57.
45. Coffee RA. A dispensing device and method for forming material. PCT InternationalApplication No: PCT/GB97/01968,1998.
46. Smith D, Reneker D, McManus A, Schreuder-Gibson H, Mello C, Sennet M, et al.Electrospun Fibers and an Apparatus Therefore. PCT International Application No:PCT/US00/27776,2001.
47. Kenawy R, Layman JM, Watkins JR, Bowlin GL, Matthews JA, Simpson DG, et al.Electrospinning of poly (ethylene-co-vinyl alcohol) fibers. Biomaterials2003;24:907-13.
48. Huang CF, Chang FC. Comparison of hydrogen bonding interaction betweenPMMA/PMAA blends and PMMA-co-PMAA copolymers. Polymer2003;44:2965-74.
49. Khil MS, Cha DI, Kim HY, Kim IS, Bhattarai N. Electrospun nanofibrous polyurethanemembrane as wound dressing. J Biomed Mater Res B2003;67:675-9.
50. Katti DS, Robinson KW, Ko FK, Laurencin CT. Bioresorbable nanofiber-based systemsfor wound healing and drug delivery: optimization of fabrication parameters. J BiomedMater Res2004;70B:286-96.
51. Min BM, Lee G, Kim SH, Nam YS, Lee TS, Park WH. Electrospinning of silk fibroinnanofibers and its effect on the adhesion and spreading of normal by humankeratinocytes and fibroblasts in vitro. Biomaterials2004;25:1289-97.
52. Min BM, Jeong L, Nam YS, Kim JM, Kim JY, Park WH. Formation of silk fibroinmatrices with different texture and its cellular response to normal human keratinocytes.Int J Biol Macromol2004;34:223-30.
53. Wnek GE, Carr ME, Simpson DG, Bowlin GL. Electrospinning of nanofibersfibrinogen structures. Nano Lett2003;3:213-6.
54. Jia J, Duan YY, Wang SH, Zhang SF, Wang ZY. Preparation and characterization ofantibacterial silver-containing nanofibers for wound dressing applications. J US-ChinaMed Sci2007;4:52-4.
55. Spasova M, Paneva D, Manolova N, Radenkov P, Rashkov I. Electrospun chitosancoated fibers of poly (l-lactide) and poly (l-lactide)/poly (ethyleneglycol): preparationand characterization. Macromol Biosci2008;8:153-62
56. Kost J, Langer R. Responsive polymeric delivery systems. Adv Drug Deliv Rev2001;46:125-48.
57. Verreck G, Chun I, Peeters J, Rosenblatt J, Brewster ME. Preparation andcharacterization of nanofibers containing amorphous drug dispersions generated byelectrostatic spinning. Pharm Res2003;20:810-7.
58. Zong X, Fang D, Kim K, Ran S, Hsiao BS, Chu B, et al. Nonwoven nanofibermembranes of poly (lactide) and poly (glycolide-co-lactide) via electrospinning andapplication for antiadhesions. Polym. Preprints-Am Chem Soc Div Polym Chem2002;43:659-60.
59. Luu YK, Kim K, Hsiao BS, Chu B, Hadjiargyrou M. Development of a nanostructuredDNA delivery scaffold via electrospinning of PLGA and PLA-PEG block copolymers. JControl Release2003;89:341-53
60. Zeng J, Xu X, Chen X, Liang Q, Bian X, Yang X, et al. Biodegradable electrospunfibers for drug delivery. J Control Release2003;92:227-31
61. Jiang HL, Fang DF, Hsiao D, Chu B, Chen WL. Preparation and characterization ofibuprofen-loaded poly (lactide-co-clycolide)/poly (ethyleneglycol)-g-chitosanelectrospun membranes. J Biomater Sci Polym Ed2004;15:279-96.
62. Kim K, Luu YK, Chang C, Fang D, Hsiao BS, Chu B, et al. Incorporation andcontrolled release of a hydrophilic antibiotic using poly(lactide-co-glycolide)-basedelectrospun nanofibrous scaffolds. J Control Release2004;98:47-56.
63. Zhang YZ, Venugopal J, Huang ZM, Lim CT, Ramakrishna S. Crosslinking of theelectrospun gelatin nanofibers. Polymer2006;47:2911-7.
64. Sun ZC, Zussman E, Yarin AL, Wendorff JH, Greiner A. Compound core-shell polymernanofibers by co-electrospinning. Adv Mater2003;15:1929-32.
65. Dosunmu OO, Chase GG, Kantaphinan W, Reneker DH. Electrospinning of polymernanofibres from multiple jets on a porous tubular surface. Nanotechnology2006;17:1123-7.
66. Theron SA, Yarin AL, Zussman E, Kroll E. Multiple jets in electrospinning: experimentand modeling. Polymer2005;46:2889-99.
67. Wang X, Um IC, Fang D, Okamoto A, Hsiao BS, Chu B. Formation of water-resistanthyaluronic acid nanofibers by blowing-assisted electro-spinning and non-toxic posttreatments. Polymer2005;46:4853-67.
68. Thomas V, Jose MV, Chowdhury S, Sullivan JF, Dean DR, Vohra YK.Mechano-morphological studies of aligned nanofibrous scaffolds of polycaprolactonefabricated by electrospinning. J Biomater Sci Polym Ed2006;17:969-84.
69. Yang F, Murugan R, Wang S, Ramakrishna S. Electrospinning of nano/microscalepoly(l-lactic acid) aligned fibers and their potential in neural tissue engineering.Biomaterials2005;26:2603-10.
70. Xu CY, Inai R, Kotaki M, Ramakrishna S. Aligned biodegradable nanofibrous structure:a potential scaffold for blood vessel engineering. Biomaterials2004;25:877-86.
71. Chuangchote S, Supaphol P. Fabrication of aligned poly (vinyl alcohol) nanofibers byelectrospinning. J Nanosci Nanotechnol2006;6:125-9.
72. Ayres C, Bowlin GL, Henderson SC, Taylor L, Shultz J, Alexander J, et al. Modulationof anisotropy in electrospun tissue-engineering scaffolds: analysis of fiber alignment bythe fast Fourier transform. Biomaterials2006;27:5524-34.
2.熊兰,漆洪波,姚陈果,米彦,王士彬.电刺激促进创伤修复的研究进展.国外医学生物医学工程分册2005;28(3):184-7.
3.宋亚文,谢利民.电刺激促进骨折愈合的历史和现状.中国骨伤2003;16(12):764-6.
4.张立宁王兴林.电刺激对周围神经再生的影响.中国康复理论与实践2006;12(7):588-90.
5.谢肇,李起鸿.低频脉冲电磁场治疗绝经后骨质疏松的机制.中国临床康复2003;7(9):1419-21.
6. Peters EJ, Lavery LA, Armstrong DG, Fleischli JG. Electric stimulation as an adjunct toheal diabetic foot ulcers: a randomized clinical trial. Arch Phys Med Rehabil,2001;82(6):721-5
7. Li Z, Qu Y, Zhang X, Yang B. Bioactive nano-titania ceramics with biomechanicalcompatibility prepared by doping with piezoelectric BaTiO3. Acta Biomater2009;5:2189-95.
8. Bouaziz A, Richert A, Caprani A. Vascular endothelial cell responses to differentelectrically charged poly(vinylidene fluoride) supports under static and oscillating flowconditions. Biomaterials1997;18:107-12.
9. Feng J, Yuan H, Zhang X. Promotion of osteogenesis by a piezoelectric biologicalceramic. Biomaterials1997;18:1531-4.
10. Valentini RF, Vargo TG, Gardella JA, Aebischer P. Electrically charged polymericsubstrates enhance nerve fiber outgrowth in vitro. Biomaterials1992;13:183-90.
11. Fine EG, Valentini RF, Bellamkonda R, Aebischer P. Improved nerve regenerationthrough piezoelectric vinylidenefluoride-trifluoroethylene copolymer guidancechannels. Biomaterials1991;12:775-80.
12.李争彩,林书玉.聚偏氟乙烯的性能以及和压电陶瓷的比较.菏泽学院学报2007;29(2):51-4.
13.张军英,李新开,王清海,冀克俭.聚偏氟乙烯的晶体结构及应用.工程塑料应用2008;36(12):79-81.
14.杜春慧,操建华,左丹英,朱宝库,徐又一.聚偏氟乙烯的多晶型及结晶行为的研究进展.功能材料2004;35:3325-9.
15. Andrew JS, Mack JJ, Clarke DR. Electrospinning of polyvinylidene difluoride-basednanocomposite fibers. J Mater Res2008;23:105-14.
16. Ren X, Dzenis Y. Novel continuous poly(vinylidene fluoride) nanofibers. Mater ResSoc Symp Proc.2006;920:55-62.
17. Zhao Z, Li J, Yuan X, Li X, Zhang Y, Sheng J. Preparation and properties ofelectrospun poly(vinylidene fluoride) membranes. J Appl Polym Sci2005;97:466-74.
18. Koombhongse S, Liu W, Reneker DH. Flat polymer ribbons and other shapes byelectrospinning. J Polym Sci Pol Phys2001;39:2598-606.
19.薛聪,胡影影,黄争鸣.静电纺丝原理研究进展.高分子通报2009;(6):38-47.
20.佟艳斌.静电纺丝技术研究及纳米纤维的应用前景.内蒙古民族大学学报2008;14(4):18-20.
21.王兴雪,王海涛,钟伟,杜强,许元泽.静电纺丝纳米纤维的方法与应用现状.非织造布2007;15(2):14-20.
22.王艳春,逯春民.静电纺丝纳米纤维在特殊领域的研究现状和应用.高科技纤维与应用2006;31(1):45-8.
23.吴卫星,段斌,袁晓燕,姚康德.静电纺丝制备聚合物超细纤维的研究及应用.材料导报2005;19(2):72-5.
24. Sill TJ, Von Recum HA. Electrospinning: Applications in drug delivery and tissueengineering. Biomaterials2008;29:1989-2006.
25. Weber N, Lee YS, Shanmugasundaram S, Jaffe M, Arinzeh TL. Characterization and invitro cytocompatibility of piezoelectric electrospun scaffolds. Acta Biomater2010;6:3550-6.
1.刘太奇,许远秦,操彬彬,陈曦.熔体静电纺丝及其装置的研究进展.新技术新工艺2009;(12):93-6.
2.李珍,王军.静电纺丝可纺性影响因素的研究成果.合成纤维2008;(9):6-11.
3.刘芸,戴礼兴.静电纺丝纤维形态及其主要影响因素.合成技术及应用2005;20(1):25-9.
4.于才渊,于春健,朱琳.静电雾化的理论研究及技术应用的进展.干燥技术与设备2003;(1):12-4.
5. Andrew JS, Clarke DR. Effect of electrospinning on the ferroelectric phase content ofpolyvinylidene difluoride fibers. Langmuir2008;24:670-2.
6. Fong H, Chun I, Reneker DH. Beaded nanofibers formed during electrospinning.Polymer1999;40:4585-92.
7.齐中华，俞昊，张瑜，陈彦模.三氯甲烷/乙醇混合溶剂对聚乳酸电纺成形影响的研究.合成纤维2009;(3):40-4.
1. Hattori T, Ohigashi H, Hikosaka M. The crystallization behaviour and phase diagram ofextended-chain crystals of poly(vinylidene fluoride) under high pressure. Polymer1996;37:85-91.
2. Bormashenko Y, Pogreb R, Stanevsky O, Bormashenko E. Vibrational spectrum ofPVDF and its interpretation. Polym Test2004;23:791-6.
3. Salimi A, Yousefi AA. Analysis Method FTIR studies of β-phase crystal formation instretched PVDF films. Polym Test2003;22:699-704.
4. Andrew JS, Clarke DR. Effect of electrospinning on the ferroelectric phase content ofpolyvinylidene difluoride fibers. Langmuir2008;24:670-2.
5. Neidh fer M, Beaume F, Ibos L, Bernèsc A. Lacabannec C. Structural evolution ofPVDF during storage or annealing. Polymer2004;45:1679-88.
6. Laroche G, Marois Y, Guidoin R, King MW, Martin L, How T, Douville Y.Polyvinylidene fluoride (PVDF) as a biomaterial: From polymeric raw material tomonofilament vascular suture. J Biomed Mater Res1995;29:1525-36.
7. Sencadas V, Lanceros-Méndez S, Mano JF. Characterization of poled and non-poledβ-PVDF films using thermal analysis techniques. Thermochim Acta2004;424:201-7.
8. Jungnickel BJ. Poly (vinylidene fluoride)(overview) in: J.C. Salamone (Ed), PolymericMaterials Handbook. CRC Press Inc, NewYork1999;p.7115-22.
1.秦全红.成纤维细胞在皮肤创伤愈合中的作用及其调控.国外医学·创伤与外科基本问题分册2000;21(1):33-8.
2.宋少岩,刘志成.聚乳酸生物材料灭菌方法的研究.中国医疗器械信息2009;15(9):28-30.
3. Weber N, Lee YS, Shanmugasundaram S, Jaffe M, Arinzeh TL. Characterization and invitro cytocompatibility of piezoelectric electrospun scaffolds. Acta Biomater2010;6:3550-6.
1. Zhang J, Wang JH. Mechanobiological response of tendon stem cells: implications oftendon homeostasis and pathogenesis of tendinopathy. J Orthop Res2010;28(5):639-43.
2. Hao Y, Xu C, Sun SY, Zhang FQ. Cyclic stretching force induces apoptosis in humanperiodontal ligament cells via caspase-9. Arch Oral Biol2009;54:864-70.
3. Wescott DC, Pinkerton MN, Gaffey BJ, Beggs KT, Milne TJ, Meikle MC. OsteogenicGene Expression by Human Periodontal Ligament Cells under Cyclic Tension. J DentRes2007;86(12):1212-6.
4. Tang L, Lin Z, Li YM. Effects of different magnitudes of mechanical strain onOsteoblasts in vitro. Biochem Biophys Res Commun2006;344(1):122-8.
5. Yang YQ, Li XT, Rabie AB, Fu MK, Zhang D. Human periodontal ligament cellsexpress osteoblastic phenotypes under intermittent force loading in vitro. Front Biosci2006;11:776-81.
6. Kanno T, Takahashi T, Ariyoshi W. Tensile Mechanical Strain Up-Regulates Runx2andOsteogenic Factor Expression in Human Periosteal Cells: Implications for DistractionOsteogenesis. J Oral Maxil Surg2005;63:499-504.
7.沈敏,田学隆,张平意,李烽.基于直流电刺激的细胞生长培养系统的研制.医疗卫生装备2005;26(5):19-20.
1. Zeleny J. The electrical discharge from liquid points, and a hydrostatic method ofmeasuring the electric intensity at their surfaces. Phys Rev1914;3:69-91.
2. Formhals A. Process and apparatus for preparing artificial threads. US Patent No.1975504,1934.
3. Vonnegut B, Newbauer RL. Production of monodisperse liquid particles by electricalatomization. J Colloid Sci1952;7:616-22.
4. Drozin VG. The electrical dispersion of liquids as aerosols. J Colloid Sci1955;10:158-64.
5. Simons HL. Process and Apparatus for Producing Patterned Nonwoven Fabrics. USPatent3280229,1966.
6. Baumgarten PK. Electrostatic spinning of acrylic microfibers. J Colloid Interface Sci1971;36:71-9.
7. Ramakrishna S, Fujihara K, Teo WE, Yong T, Ma Z, Ramaseshan R. Electrospunnanofibers: solving global issues. Mater Today2006;9:40-50.
8. Kidoaki S, Kwon IK, Matsuda T. Mesoscopic spatial designs of nano and microfibermeshes for tissue-engineering matrix and scaffold based on newly devisedmultilayering and mixing electrospinning techniques. Biomaterials2005;26:37-46.
9. Stankus JJ, Guan J, Fujimoto K, Wagner WR. Microintegrating smooth muscle cellsinto a biodegradable, elastomeric fiber matrix. Biomaterials2006;27:735-44.
10. Taylor GI. Electrically Driven Jets. Proc R Soc Lond, A Math Phys Sci,(1934-1990),1969;313,453-75.
11. Andrew JS, Clarke DR. Effect of electrospinning on the ferroelectric phase content ofpolyvinylidene difluoride fibers. Langmuir2008;24:670-2.
12. Chong EJ, Phan TT, Lim IJ, Zhang YZ, Bay BH, Ramakrishna S, et al. Evaluation ofelectrospun PCL/gelatin nanofibrous scaffold forwound healing and layered dermalreconstitution. Acta Mater2007;3:321–30.
13. Li D, Xia Y. Electrospinning of nanofibers: reinventing the wheel. Adv Mater2004;16:1151–70.
14. Dalton PD, Calvet JL, Mourran A, Klee D, M ller M. Melt electrospinning ofpoly(ethylene glycol-block-ε-caprolactone). Biotechnol J2006;1:998-1006.
15. Kim JS, Lee DS. Thermal properties of electrospun polyesters. Polym J2000;32:616–8.
16. Chun I, Reneker DH, Fong H, Fang X, Deitzel J, Tan NB, et al. Carbon nanofibers frompolyacrylonitrile and mesophase pitch. J Adv Mater1999;31:36–41.
17. Zhou H, Green TB, Joo YL. The thermal effects on electrospinning of polylactic acidmelts. Polymer2006;47:7497–505.
18. Zhmayev E, Zhou H, Joo YL. Modeling of non-isothermal polymer jets in meltelectrospinning. J Non-Newtonian Fluid Mech2008;153:95-108.
19. Pierschbacher MD, Ruoslahti E. Cell attachment activity of fibronectin can beduplicated by small synthetic fragments of the molecule. Nature1984;309:30-3.
20. Zeugolis DI, Khew ST, Yew ESY, Ekaputra AK, Tong YW, Yung LYL, et al.Electro-spinning of pure collagen nano-fibres–just an expensive way to make gelatin?Biomaterials2008;29:2293-305.
21. Matthews JA, Wnek GE, Simpson DG, Bowlin GL. Electrospinning of collagennanofibers. Biomacromolecules2002;3:232-8.
22. Rho KS, Jeong L, Lee G, Seo BM, Park YJ, Hong SD, et al. Electrospinning of collagennanofibers: effects on the behavior of normal human keratinocytes and early-stagewound healing. Biomaterials2006;27:1452-61.
23. Zhang Y, Ouyang H, Lim CT, Ramakrishna S, Huang ZM. Electrospinning of gelatinfibers and gelatin/PCL composite fibrous scaffolds. J Biomed Mater Res B ApplBiomater2005;72:156-65.
24. Kwon IK, Matsuda T. Co-electrospun nanofiber fabrics of poly (l-lactide-co-ε-caprolactone) with type I collagen or heparin. Biomacromolecules2005;6:2096-105.
25. Zhong S, Teo WE, Zhu X, Beuerman R, Ramakrishna S, Yung LY. Formation ofcollagen-glycosaminoglycan blended nanofibrous scaffolds and their biologicalproperties. Biomacromolecules2005;6:2998-3004.
26. Hong DP, Hoshino M, Kuboi R, Goto Y. Clustering of fluorine-substituted alcohols as afactor responsible for their marked effects on proteins and peptides. J Am Chem Soc1999;121:8427-33.
27. Cort JR, Andersen NH. Formation of a molten-globule-like state of myoglobin inaqueous hexafluoroisopropanol. Biochem Biophys Res Commun1997;233:687-91.
28. Kundu A, Kishore N.1,1,1,3,3,3-Hexafluoroisopropanol induced thermal unfolding andmolten globule state of bovine alpha-lactalbumin: calorimetric and spectroscopicstudies. Biopolymers2004;73:405-20.
29. Wang M, Hsieh AJ, Rutledge GC. Electrospinning of poly (MMA-co-MAA)copolymers and their layered silicate nanocomposites for improved thermal properties.Polymer2005;46:3407-18.
30. Kenawy ER, Bowlin GL, Mansfield K, Layman J, Simpson DG, Sanders EH, et al.Release of tetracycline hydrochloride from electrospun poly (ethylene-co-vinylacetate,poly (lactic acid), and a blend. J Control Release2002;81:57-64.
31. Saito N, Okada T, Horiuchi H, Murakami N, Takahashi J, Nawata M, et al.Biodegradable polymer as a cytokine delivery system for inducing bone formation. NatBiotechnol2001;19:332-5.
32. Langer R, Vacanti JP. Tissue Engineering. Science1993;260:920-6.
33. Nerem RM, Sambanis A. Tissue engineering: from biology to biological substitutes.Tissue Eng1995;1:3-13.
34. Hubbell JA. Biomaterials in tissue engineering. Biotechnology1995;13:565-76.
35. Friess W. Collagen–biomaterial for drug delivery. Eur J Pharm Biopharm1998;45:113-36.
36. He W, Horn SW, Hussain MD. Improved bioavailability of orally administeredmifepristone from PLGA nanoparticles. Int J Pharm2007;334:173-8.
37. Li WJ, Laurencin CT, Caterson EJ, Tuan RS, Ko FK. Electrospun nanofibrous structure:a novel scaffold for tissue engineering. J Biomed Mater Res2002;60:613-21.
38. Li C, Vepari C, Jin HJ, Kim HJ, Kaplan DL. Electrospun silk-BMP-2scaffolds for bonetissue engineering. Biomaterials2006;27:3115-24.
39. Li M, Mondrinos MJ, Gandhi MR, Ko FK, Weiss AS, Lelkes PI. Electrospun proteinfibers as matrices for tissue engineering. Biomaterials2005;26:5999-6008.
40. Yoshimoto H, Shin YM, Terai H, Vacanti JP. A biodegradable nanofiber scaffold byelectrospinning and its potential for bone tissue engineering. Biomaterials2003;24:2077-82.
41. Tuan RS, Boland G, Tuli R. Adult mesenchymal stem cells and cell-based tissueengineering. Arthritis Res Ther2003;5:32-45.
42. Jin HJ, Chen J, Karageorgiou V, Altman GH, Kaplan DL. Human bone marrow stromalcell responses to electrospun silk fibroin mats. Biomaterials2004;25:1039-47.
43. Ki CS, Kim JW, Hyun JH, Lee KH, Hattori M, Rah DK, et al. Electrospun threedimensional silk fibroin nanofibrous scaffold. J Appl Polym Sci2007;106:3922-8.
44. Thomas S. Wound management and dressings. Pharm Presse1990;1:37-57.
45. Coffee RA. A dispensing device and method for forming material. PCT InternationalApplication No: PCT/GB97/01968,1998.
46. Smith D, Reneker D, McManus A, Schreuder-Gibson H, Mello C, Sennet M, et al.Electrospun Fibers and an Apparatus Therefore. PCT International Application No:PCT/US00/27776,2001.
47. Kenawy R, Layman JM, Watkins JR, Bowlin GL, Matthews JA, Simpson DG, et al.Electrospinning of poly (ethylene-co-vinyl alcohol) fibers. Biomaterials2003;24:907-13.
48. Huang CF, Chang FC. Comparison of hydrogen bonding interaction betweenPMMA/PMAA blends and PMMA-co-PMAA copolymers. Polymer2003;44:2965-74.
49. Khil MS, Cha DI, Kim HY, Kim IS, Bhattarai N. Electrospun nanofibrous polyurethanemembrane as wound dressing. J Biomed Mater Res B2003;67:675-9.
50. Katti DS, Robinson KW, Ko FK, Laurencin CT. Bioresorbable nanofiber-based systemsfor wound healing and drug delivery: optimization of fabrication parameters. J BiomedMater Res2004;70B:286-96.
51. Min BM, Lee G, Kim SH, Nam YS, Lee TS, Park WH. Electrospinning of silk fibroinnanofibers and its effect on the adhesion and spreading of normal by humankeratinocytes and fibroblasts in vitro. Biomaterials2004;25:1289-97.
52. Min BM, Jeong L, Nam YS, Kim JM, Kim JY, Park WH. Formation of silk fibroinmatrices with different texture and its cellular response to normal human keratinocytes.Int J Biol Macromol2004;34:223-30.
53. Wnek GE, Carr ME, Simpson DG, Bowlin GL. Electrospinning of nanofibersfibrinogen structures. Nano Lett2003;3:213-6.
54. Jia J, Duan YY, Wang SH, Zhang SF, Wang ZY. Preparation and characterization ofantibacterial silver-containing nanofibers for wound dressing applications. J US-ChinaMed Sci2007;4:52-4.
55. Spasova M, Paneva D, Manolova N, Radenkov P, Rashkov I. Electrospun chitosancoated fibers of poly (l-lactide) and poly (l-lactide)/poly (ethyleneglycol): preparationand characterization. Macromol Biosci2008;8:153-62
56. Kost J, Langer R. Responsive polymeric delivery systems. Adv Drug Deliv Rev2001;46:125-48.
57. Verreck G, Chun I, Peeters J, Rosenblatt J, Brewster ME. Preparation andcharacterization of nanofibers containing amorphous drug dispersions generated byelectrostatic spinning. Pharm Res2003;20:810-7.
58. Zong X, Fang D, Kim K, Ran S, Hsiao BS, Chu B, et al. Nonwoven nanofibermembranes of poly (lactide) and poly (glycolide-co-lactide) via electrospinning andapplication for antiadhesions. Polym. Preprints-Am Chem Soc Div Polym Chem2002;43:659-60.
59. Luu YK, Kim K, Hsiao BS, Chu B, Hadjiargyrou M. Development of a nanostructuredDNA delivery scaffold via electrospinning of PLGA and PLA-PEG block copolymers. JControl Release2003;89:341-53
60. Zeng J, Xu X, Chen X, Liang Q, Bian X, Yang X, et al. Biodegradable electrospunfibers for drug delivery. J Control Release2003;92:227-31
61. Jiang HL, Fang DF, Hsiao D, Chu B, Chen WL. Preparation and characterization ofibuprofen-loaded poly (lactide-co-clycolide)/poly (ethyleneglycol)-g-chitosanelectrospun membranes. J Biomater Sci Polym Ed2004;15:279-96.
62. Kim K, Luu YK, Chang C, Fang D, Hsiao BS, Chu B, et al. Incorporation andcontrolled release of a hydrophilic antibiotic using poly(lactide-co-glycolide)-basedelectrospun nanofibrous scaffolds. J Control Release2004;98:47-56.
63. Zhang YZ, Venugopal J, Huang ZM, Lim CT, Ramakrishna S. Crosslinking of theelectrospun gelatin nanofibers. Polymer2006;47:2911-7.
64. Sun ZC, Zussman E, Yarin AL, Wendorff JH, Greiner A. Compound core-shell polymernanofibers by co-electrospinning. Adv Mater2003;15:1929-32.
65. Dosunmu OO, Chase GG, Kantaphinan W, Reneker DH. Electrospinning of polymernanofibres from multiple jets on a porous tubular surface. Nanotechnology2006;17:1123-7.
66. Theron SA, Yarin AL, Zussman E, Kroll E. Multiple jets in electrospinning: experimentand modeling. Polymer2005;46:2889-99.
67. Wang X, Um IC, Fang D, Okamoto A, Hsiao BS, Chu B. Formation of water-resistanthyaluronic acid nanofibers by blowing-assisted electro-spinning and non-toxic posttreatments. Polymer2005;46:4853-67.
68. Thomas V, Jose MV, Chowdhury S, Sullivan JF, Dean DR, Vohra YK.Mechano-morphological studies of aligned nanofibrous scaffolds of polycaprolactonefabricated by electrospinning. J Biomater Sci Polym Ed2006;17:969-84.
69. Yang F, Murugan R, Wang S, Ramakrishna S. Electrospinning of nano/microscalepoly(l-lactic acid) aligned fibers and their potential in neural tissue engineering.Biomaterials2005;26:2603-10.
70. Xu CY, Inai R, Kotaki M, Ramakrishna S. Aligned biodegradable nanofibrous structure:a potential scaffold for blood vessel engineering. Biomaterials2004;25:877-86.
71. Chuangchote S, Supaphol P. Fabrication of aligned poly (vinyl alcohol) nanofibers byelectrospinning. J Nanosci Nanotechnol2006;6:125-9.
72. Ayres C, Bowlin GL, Henderson SC, Taylor L, Shultz J, Alexander J, et al. Modulationof anisotropy in electrospun tissue-engineering scaffolds: analysis of fiber alignment bythe fast Fourier transform. Biomaterials2006;27:5524-34.
© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |