Production of chitosan scaffolds by lyophilization or electrospinning: which is better for peripheral nerve regeneration?

Both lyophilization and electrospinning are commonly used to make chitosan scaffolds.However,it remains unknown which method is better for cell growth.In this study,we established the following groups:(1)lyophilization group-chitosan scaffolds were prepared by lyophilization method and seeded with Schwann cells from Sprague-Dawley rats aged 3-5 days;(2)electrospinning group-chitosan scaffolds were prepared by electrospinning method and seeded with Schwann cells;(3)control group-Schwann cells were cultured on culture dishes.The growth of Schwann cells was evaluated by immunofluorescence and scanning electron microscopy.Western blot assay was performed to explore the mechanism of Schwann cell growth.Both materials were non-toxic and suitable for the growth of Schwann cells.The pores produced by electrospinning were much smaller than those produced by lyophilization.The proliferation rate and adhesion rate of Schwann cells in the electrospinning group were higher than those in the lyophilization group.Schwann cells cultured on electrospinning scaffolds formed a Bungner band-like structure,and a much greater amount of brain-derived neurotrophic factor was secreted,which can promote the growth of neurons.Our findings show that the chitosan scaffold prepared by the electrospinning method has a nanofiber structure that provides an extracellular matrix that is more favorable for cell-cell interactions.The electrospinning method is more suitable for nerve regeneration than the lyophilization method.This research was approved by the Medical Ethical Committee of Dalian Medical University(approval No.AEE1-2016-045)on March 3,2016.