Synergistic effects of electrospun PLLA fiber dimension and pattern on neonatal mouse cerebellum C17.2 stem cells.

Topographical features, including fiber dimensions and pattern, are important aspects in developing fibrous scaffolds for tissue engineering. In this study aligned poly(l-lactide) (PLLA) fibers with diameters of 307+/-47, 500+/-53, 679+/-72 and 917+/-84 nm and random fibers with diameters of 327+/-40, 545+/-54, 746+/-82 and 1150+/-109 nm were obtained by optimizing the electrospinning parameters. We cultured neonatal mouse cerebellum C17.2 cells on the PLLA fibers. These neural stem cells (NSCs) exhibited significantly different growth and differentiation depending upon fiber dimension and pattern. On aligned fibers cell viability and proliferation was best on 500 nm fibers, and reduced on smaller or larger fibers. However, on random fibers cell viability and proliferation was best with the smallest (350 nm) and largest (1150 nm) diameter fibers. Polarized and elongated cells were orientated along the fiber direction on the aligned fibers, with focal contacts bridging the cell body and aligned fibers. Cells of spindle and polygonal morphologies were randomly distributed on the random fibers, with no focal contacts observed. Moreover, longer neurites were obtained on the aligned fibers than random fibers within the same diameter range. Thus, the surface topographic morphologies of fibrous scaffolds, including fiber pattern, dimensions and mesh size, play roles in regulating the viability, proliferation and neurite outgrowth of NSCs. Nevertheless, our results indicated that aligned 500 nm fiber are most promising for fine tuning the design of a nerve scaffold.