The influence of fibre diameter of electrospun substrates on Schwann cell behaviour and axonal outgrowth for nerve tissue engineering.

For tissue engineering applications, the distribution and growth of cells on a scaffold are key requirements. Appropriate fibrous substrates, functioning as a temporary extracellular matrix, can be easily prepared by electrospinning, which allows the obtainment fibrous matrices suitable as internal filler for nerve guidance channels (NGCs) to be applied in peripheral nerve repair. Gelatin micro or nano-fibres have been prepared by electrospinning technique by tuning gelatin concentration and solution flow rate. The influence of gelatine fibre diameter on cell adhesion and proliferation, was tested in vitro by using Schwann cells (SC) and Dorsal Root Ganglia (DRG) explant cultures. Cell adhesion was evaluated by quantifying cell spreading area, actin cytoskeleton organization and focal adhesion complex formation. Nano-fibres have been shown to promote cell spreading and actin cytoskeleton organization, resulting in higher cellular adhesion and proliferation rate in comparison to micro-fibres. Cell migration and motility were quantified by transwell and time lapse assays respectively. Cells cultured on micro-fibres displayed higher motility and migration rate in comparison to nano-fibres. Finally, neuritis outgrowth evaluated by culturing DRG explants on the different fibres resulted in higher neuritis outgrowth on micro-fibres in comparison to nano-fibres. These data provide a better understanding about glial cell and neuritis viability and organization on gelatin electrospun nano- and micro-fibres suggesting that micro-fibres can be a better filler to be used in the design of new device for peripheral nerve repair application.