3D printed biodegradable hydrogel-based multichannel nerve conduits mimicking peripheral nerve fascicules

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Neuroscience

Background:

• Peripheral nerve injury (PNI) presents significant clinical challenges, often hindered by poor axonal dispersion.
• Conventional single hollow lumen nerve guidance conduits (NGCs) struggle to replicate the complex fascicular structure of native nerves.
• Multichannel NGCs offer a promising alternative by mimicking the natural nerve architecture for improved regeneration.

Purpose of the Study:

• To develop and evaluate novel 3D printed hydrogel-based multichannel NGCs for enhanced peripheral nerve regeneration.
• To investigate the role of food-grade dyes in controlling photopolymerization and achieving high-resolution printing of microscale channels.
• To assess the efficacy of these multichannel NGCs in a rat sciatic nerve injury model.

Main Methods:

• Fabrication of multichannel NGCs using digital light processing (3D printing) with biodegradable and photocurable hydrogels (Gelatin methacryloyl - GelMA and polyethylene glycol diacrylate - PEGDA).
• Incorporation of food-grade dyes into the hydrogel solution to control light penetration, prevent overcuring, and enable high-resolution printing of 200 μm diameter channels.
• In vivo evaluation in a rat sciatic nerve gap model, assessing functional recovery (sensory, gait) and histological outcomes (muscle fiber regeneration).

Main Results:

• Successfully fabricated high-resolution, microscale multichannel NGCs with precise 200 μm diameter channels.
• Demonstrated that dye addition effectively regulated polymerization and enabled fine channel printing.
• In vivo studies showed significant improvements in paw sensory recovery, hindlimb gait function, and muscle fiber regeneration in rats treated with GelMA/PEGDA multichannel NGCs.
• Characterized hydrogel properties, including mechanical strength, pore size, and biodegradation rate, confirming their suitability for nerve regeneration.

Conclusions:

• Hydrogel-based, 3D printed multichannel NGCs represent a viable and effective strategy for treating peripheral nerve injuries.
• The use of dyes in photopolymerization is crucial for achieving the necessary resolution and control in fabricating complex microchannel structures.
• These advanced NGCs show significant potential for accelerating neurologic recovery and restoring function after nerve damage.