Influence of micro and submicro poly(lactic-glycolic acid) fibers on sensory neural cell locomotion and neurite growth.

For successful peripheral nerve regeneration, a complex interplay of growth factors, topographical guidance structure by cells and extracellular matrix proteins, are needed. Aligned fibrous biomaterials with a wide variety in fiber diameter have been used successfully to support neuronal guidance. To better understand the importance of size of the topographical features, we investigated the directionality of neuronal migration of sensory ND7/23 cells on aligned electrospun poly(lactic-glycolic acid) PLGA fibers in the range of micrometer and submicrometer diameters by time-lapse microscopy. Cell trajectories of single ND7/23 cells were found to significantly follow topographies of PLGA fibers with micrometer dimensions in contrast to PLGA fibers within the submicrometer range, where cell body movement was observed to be independent of fibrous structures. Moreover, neurite alignment of ND7/23 cells on various topographies was assessed. PLGA fibers with micrometer dimensions significantly aligned 83.3% of all neurites after 1 day of differentiation compared to similar submicrometer structures, which orientated 25.8% of all neurites. Interestingly, after 7 days of differentiation ND7/23 cells on submicrometer PLGA fibers increased their alignment of neurites to 52.5%. Together, aligned PLGA fibers with micrometer dimensions showed a superior influence on directionality of neuronal migration and neurite outgrowth of sensory ND7/23 cells, indicating that electrospun micro-PLGA fibers might represent a potential material to induce directionality of neuronal growth in engineering applications for sensory nerve regeneration.