Department of Bioengineering, Rice University, Houston, TX, USA.
J Control Release. 2010 Apr 2;143(1):95-103. doi: 10.1016/j.jconrel.2009.12.009. Epub 2009 Dec 16.
In an effort to add to the versatility of three-dimensional scaffolds for tissue engineering applications, recent experimental designs are incorporating biological molecules such as plasmids and proteins within the scaffold structure. Such scaffolds act as reservoirs for the biological molecules of interest while regulating their release over various durations of time. Here, we describe the use of coaxial electrospinning as a means for the fabrication of fiber mesh scaffolds and the encapsulation and subsequent release of a non-viral gene delivery vector over a period of up to 60 days. Various fiber mesh scaffolds containing plasmid DNA (pDNA) within the core and the non-viral gene delivery vector poly(ethylenimine)-hyaluronic acid (PEI-HA) within the sheath of coaxial fibers were fabricated based on a fractional factorial design that investigated the effects of four processing parameters at two levels. Poly(epsilon-caprolactone) sheath polymer concentration, poly(ethylene glycol) core polymer molecular weight and concentration, and the concentration of pDNA were investigated for their effects on average fiber diameter, release kinetics of PEI-HA, and transfection efficiency. It was determined that increasing the values of each of the investigated parameters caused an increase in the average diameter of the fibers. The release kinetics of PEI-HA from the fibers were affected by the loading concentration of pDNA (with PEI-HA concentration adjusted accordingly to maintain a constant nitrogen to phosphorous (N:P) ratio within the complexes). Two-dimensional cell culture experiments with model fibroblast-like cells demonstrated that complexes of pDNA with PEI-HA released from fiber mesh scaffolds could successfully transfect cells and induce expression of enhanced green fluorescent protein (EGFP). Peak EGFP expression varied with the investigated processing parameters, and the average transfection observed was a function of poly(ethylene glycol) (core) molecular weight and concentration. Furthermore, fibroblast-like cells seeded directly onto coaxial fiber mesh scaffolds containing PEI-HA and pDNA showed EGFP expression over 60 days, which was significantly greater than the EGFP expression observed with scaffolds containing pDNA alone. Hence, variable transfection activity can be achieved over extended periods of time upon release of pDNA and non-viral gene delivery vectors from electrospun coaxial fiber mesh scaffolds, with release and subsequent transfection controlled by tunable coaxial fiber mesh fabrication parameters.
为了增加组织工程应用的三维支架的多功能性，最近的实验设计将生物分子如质粒和蛋白质纳入支架结构中。这种支架充当感兴趣的生物分子的储库，同时调节它们在不同时间长度内的释放。在这里，我们描述了使用同轴静电纺丝作为制造纤维网支架的方法，以及在长达 60 天的时间内封装和随后释放非病毒基因传递载体。根据考察四个加工参数在两个水平上的影响的部分因子设计，在核心中含有质粒 DNA(pDNA)的各种纤维网支架和在同轴纤维鞘中的非病毒基因传递载体聚(亚乙基亚胺)-透明质酸(PEI-HA)被制造出来。聚(己内酯)鞘聚合物浓度、聚(乙二醇)芯聚合物分子量和浓度以及 pDNA 浓度被考察其对平均纤维直径、PEI-HA 的释放动力学和转染效率的影响。结果表明，增加每个研究参数的值会导致纤维平均直径增加。PEI-HA 从纤维中的释放动力学受 pDNA 加载浓度的影响(相应调整 PEI-HA 浓度以保持复合物中的氮到磷(N:P)比恒定)。用模型成纤维样细胞进行的二维细胞培养实验表明，从纤维网支架中释放的 pDNA 与 PEI-HA 的复合物能够成功转染细胞并诱导增强型绿色荧光蛋白(EGFP)的表达。EGFP 表达的峰值随研究的加工参数而变化，观察到的平均转染效率是聚乙二醇(芯)分子量和浓度的函数。此外，直接接种到含有 PEI-HA 和 pDNA 的同轴纤维网支架上的成纤维样细胞在 60 天内表现出 EGFP 表达，明显高于单独含有 pDNA 的支架上观察到的 EGFP 表达。因此，通过从同轴纤维网支架中释放 pDNA 和非病毒基因传递载体，可以在延长的时间内实现可变的转染活性，释放和随后的转染受可调谐的同轴纤维网制造参数控制。
