Introduction We employed a nanosilver-collagen scaffold and tested its effects on inhibiting bacteria and facilitating nerve regeneration. Methods Based on our previous research, we prepared bionic scaffolds with different concentrations of nanosilver and examined their internal structures by scanning electron microscopy and energy dispersive spectroscopy. We implanted these scaffolds or autologous nerve grafts into rats to repair a 10-mm injury of the sciatic nerve. Results The 2 mg/ml group showed a >10 mm bacterial inhibition zone in all 3 types of bacterial culture dishes. At day 60 postsurgery, the 2 mg/ml group also showed the highest amplitude of evoked potential (AMP) and nerve conduction velocity (NCV). The regenerating nerves in the 2 mg/ml group were denser and more mature, and with thicker and well-arrayed myelin sheath. Conclusions These results demonstrate that nanosilver scaffolds (2 mg/ml group) were effective in inhibiting bacteria both in vitro and in vivo, and reduced the contamination-caused immune responses, which in turn promoted nerve regeneration and functional recovery.

Design and construction of biocompatible tissue-eng ineered stents for long segment peripheral nerve re gen ration has become a significant research topic. However, i n the early of damaged, the immigration and aggrega tion of inflammatory cells and factors can induce a seconda ry nerve injury and peroxide damage to the injured nerves, which in turn can result in severe neuronal apoptos is. The use of immunosuppressant in the injury site can reduce the inflammatory reactions and secondary injury, an d build a conducive microenvironment for nerve rege neration. In this study, we prepared tissue-engineering perip heral nerve stent using FK506, where the release of fk506 into the periphery after microsphere degradation still needs to pass through the stent wall. Such double effect of slow-release significantly reduced the burst release and prolong ed the full release to 17 days. In our rat model of repairing a 20 mm sciatic nerve defect, 3 months after the surgery , the SFI and electrophysiological testing results of the ipsilateral side in group 1(FK506+PLGA+Stent) showed no signifi cant difference from those in the autologous nerve grafting group. Morphological results also indicated that in terms of either the number of regenerated axons or the degree of myelin maturity, the regeneration outcome in group 1 was close to that in autologous nerve grafting gr oup and significantly superior over that in the group 2(Onl y Stent). The slow-release FK506-eluting stent intr oduced in this study is easy for clinical application and provides a new experimental evidence of promoting periphera l nerve regeneration with tissue-engineering methods.

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.