Elsevier

Materials Science and Engineering: C

Volume 83, 1 February 2018, Pages 130-142
Materials Science and Engineering: C

Nano-fibrous and ladder-like multi-channel nerve conduits: Degradation and modification by gelatin

https://doi.org/10.1016/j.msec.2017.11.020Get rights and content

Highlights

  • Gelatin coating was used for modifying multi-channel nanofibrous nerve conduits.

  • Gelatin modification improved the flexibility, degradation and biocompatibility.

  • Nanofibers and bioactivity play a synergistic effect on neuron-oriented differentiation.

Abstract

We recently fabricated multi-channel PLLA nerve conduits (NCs, conduits diameter: ~ 3 mm, channels diameter: ~ 200 μm) with nano-fibrous microstructure (NNCs) and ladder-like microstructure (LNCs), and found the nanofibers in the NNCs promote differentiation of nerve stem cells (NSCs) into neurons. In the present study, we evaluated the degradation profile of NNCs and LNCs, and observed that NNCs degraded too fast to implant. To delay the degradation and retain the nano-scale effect of NNCs, we used gelatin to wrap (2% w/v gelatin) or embed (8% w/v gelatin) NNCs and LNCs via vacuum infusion and chemical cross-linking with genipin. NNCs-wrapped maintained their original nano-fibrous microstructure, but NNCs-embedded presented a porous morphology without nanofibers appearing. Incorporation of gelatin did not change their compressive moduli, but increased the creep recovery ratios of LNCs and NNCs. In vitro degradation revealed that integrity was maintained and the mass loss was < 5% for NNCs-wrapped after 10 weeks, in comparison with 15% mass loss and collapsed structure of the pure NNCs after 4 weeks. Meanwhile, there were no obvious changes in the degradation of LNCs with modification. Nerve stem cells (NSCs) were then seeded onto the six NCs represented as: NNCs, NNCs-wrapped, NNCs-embedded, LNCs, LNCs-wrapped, and LNCs-embedded. Immunocytochemistry analysis demonstrated that gelatin coating enhanced the adhesion and proliferation of NSCs, and the NNCs-wrapped scaffold promoted the differentiation proportion of NSCs into neurons from 25.8% (on pure NNCs) to 53.4% after 14 days of seeding. On the other hand, only 14.3% of neurons were derived from the differentiation of the seeded NSCs on the NNCs-embedded. NNCs-wrapped would be a good choice for future studies in nerve injury repair in vivo due to its appropriate degradation rate, flexibility, and nano-scale effect.

Keywords

PLLA
Nanofibrous multi-channel nerve conduits
Gelatin modification
Flexibility
Delay degradation
Neural stem cells behavior

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