Electrospun Gelatin Constructs with Tunable Fiber Orientation Promote Directed Angiogenesis

The field of therapeutic angiogenesis has been predominantly concentrated in modalities that incorporate pro-angiogenic growth factors and/or cells within polymeric constructs that are implanted into the ischemic region. There is growing evidence that construct architecture can significantly affect growth factor activity, cellular viability and differentiation potential. Electrospinning is an attractive but simple scaffold fabrication technique that offers several advantages over traditional fabrication approaches to prepare highly organized structures for therapeutic angiogenesis applications. We recently described the fabrication of nanofibrous scaffolds with aligned fiber orientation that directed cell migration and orientation (i.e.human umbilical vein endothelial cells). Herein we demonstrate the ability of bFGF containing nanofibrous gelatin B scaffolds with controlled fiber orientation to promote capillary formation in vivo. Aligned scaffolds loaded with bFGF induced the highest levels of reperfusion (73% increased in LDPI ratios by day 21 post ischemia induction) in comparison to all other groups including scaffolds with random fiber orientation. Furthermore, the newly formed vasculature, assessed by confocal microscopy, had a parallel alignment along the axis of the scaffold’s fibers. In contrast, no vessel directionality was observed in the animals treated with scaffolds with random fiber orientation in the presence or absence of bFGF.