3. Results
3.1. Nanofiber fabrication and physical characterization
We have previously fabricated nanofibers with tunable fiber thickness and porosities using RJS [11] and [17]. In this study, we asked if we could create highly aligned, anisotropic hybrid protein-polymer nanofibers by the same method. For this purpose, we allowed the fibers that collect in the periphery of the collector to wrap around and collect around the rotating reservoir (Fig. 1A; Supplementary Video 1). The rotating reservoir provides tension to the nanofibers, creating densely packed, highly aligned nanofibrous scaffolds that we term super-aligned nanofiber (SANF) constructs (Fig. 1B). These SANF constructs demonstrate robust centimeter (Fig. 1C), millimeter (Fig. 1D), and micrometer scale (Fig. 1E) alignment. The nanofibers were bead-free with narrow diameter distribution. Fiber diameter increased with increasing protein concentration (Fig. 1F). Median fiber diameter was not significantly different between PCL, PCL/Collagen-75/25, and PCL/Gelatin-75/25 SANFs. Fiber diameter significantly increased as the percentage of protein increased to 50% and 75% (Fig. 1F). PCL/Gelatin-25/75 fibers had a median fiber diameter in excess of 1 micron and therefore require a higher RJS spinning velocity to fabricate nanofibers [11] and [17].