Construction of tissue-engineered scaffold for peripheral nerve regeneration with nano-sliver and collagen and their physical and chemical examinations

Abstract

Objective To construct a kind of nanosilver-embedded collagen scaffold for peripheral nerve regeneration and to investigate its physical and chemical characters and biocompatibility.Methods The nanosilver particles at different concentrations of 1,2,3,4,5 and 6 mg/L were added into collagen respectively while pure water of the same amount was added in the control groups.Improved cryodesiccation was used to construct the nanosilver-embedded collagen scaffold with micro-channels.The nanosilver-embedded collagen scaffold suitable for the peripheral nerve was selected according to the diameters of micro-channels upon scanning electron microscopy and the tensile strength at the axial direction of the scaffold.The in vivo cytotoxicity of the selected scaffold was tested in 5 SD newborn rats,the in vivo degradation rate of the selected scaffold in 8 adult male SD rats and the in vivo cumulative toxicity of the nanosilver in 12 adult male SD rats.The best nanosilver-embedded collagen scaffold for peripheral nerve regeneration after injury was determined according to the comprehensive properties examined.Results The micro-channels of the nanosilver-embedded collagen scaffold were the most suitable for the peripheral nerve when the concentrations of nanosilver in the collagen were 1 or 2 mg/L.Tensile strength at the axial direction of the collagen scaffold embedded with 2 mg/L nanosilver was 0.22 MPa,better than the other groups.The collagen scaffold embedded with 2 mg/L nanosilver degraded in vivo gradually and completely after 4 months with no cytotoxicity or storage of toxicity.The contents of silver in the brain,spinal cord,liver and kidney were all lower than 1 ng/mL.Conclusion The collagen scaffold embedded with 2 mg/L nanosilver best suits the peripheral nerve regeneration after injury,because it has good tensile strength,can be fully degraded in vivo,and is free from cytotoxicity or storage of toxicity. Key words: Nanocomposites; Nerve regeneration; Tissue engineering; Peripheral nerve; Tissue scaffold