3D multi-channel bi-functionalized silk electrospun conduits for peripheral nerve regeneration

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Neuroscience

Background:

• Peripheral nerve injuries often result in incomplete recovery, despite advances in treatment.
• Autografts, the current standard, have limitations including donor site morbidity and tissue availability.
• Biomimetic nerve graft substitutes offer a promising alternative for enhancing nerve regeneration.

Purpose of the Study:

• To fabricate and characterize multichanneled silk electrospun conduits bi-functionalized with Nerve Growth Factor (NGF) and Ciliary Neurotropic Factor (CNTF).
• To create a biomimetic nerve guide that mimics the native nerve's fascicular architecture and extracellular matrix.
• To evaluate the potential of these functionalized conduits for peripheral nerve regeneration.

Main Methods:

• Silk fibroin was electrospun into conduits with longitudinally oriented channels and aligned nanofibers.
• Conduits were bi-functionalized with NGF and CNTF.
• Physicochemical properties, growth factor release (ELISA), and mechanical behavior (tensile testing) were analyzed.
• Mechanical properties were compared to rat sciatic nerve.

Main Results:

• The fabricated conduits mimicked the perineurium-like structure with tunable channel dimensions.
• Silk fibroin functionalization did not alter its secondary structure or chemical properties.
• No passive release of growth factors was observed, preventing protein accumulation.
• The nerve guides exhibited mechanical properties (4.0 ± 0.6 MPa ultimate peak stress, 156.8 ± 46.7% elongation at failure) comparable to native rat sciatic nerve.

Conclusions:

• A novel bi-functionalized nerve conduit using electrospun silk nanofibers was successfully designed and characterized.
• The conduit's multichannel, aligned nanofiber structure and incorporated growth factors show potential for peripheral nerve regeneration.
• These bioactive silk tubes represent a promising biocompatible nerve guidance conduit for future clinical applications.