Bridging the gap: gradient scaffolds as bioinstructive platforms for peripheral nerve repair.

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Neuroscience

Background:

• Peripheral nerve injury presents significant clinical challenges due to poor regeneration.
• Existing nerve guidance conduits (NGCs) often lack the necessary bioinstructive cues for effective nerve repair.
• Spatial gradients are crucial biological signals for directing cell migration and axonal growth.

Purpose of the Study:

• To review the mechanisms of gradient cues in regulating cellular and axonal responses.
• To summarize advances in designing and fabricating gradient nerve guidance conduits (NGCs).
• To highlight the synergistic effects of chemical gradients and structural guidance in promoting nerve regeneration.

Main Methods:

• Review of physicochemical processes (e.g., diffusion, adsorption, polymer formation) for establishing gradients.
• Analysis of materials design and fabrication strategies for incorporating physical and biochemical gradients.
• Synthesis of in vitro and in vivo studies on gradient NGC performance.

Main Results:

• Gradient NGCs incorporate spatially encoded physical properties (topography, stiffness) and biochemical components (growth factors, ECM).
• Chemically engineered gradients synergize with structural guidance to promote organized nerve regeneration.
• Demonstrated efficacy of gradient NGCs in promoting cellular and axonal responses in vitro and in vivo.

Conclusions:

• Gradient-based NGCs represent a promising biomaterial strategy for enhancing peripheral nerve regeneration.
• Further research is needed to address challenges in gradient stability, reproducibility, and scalable manufacturing for clinical translation.
• Gradient NGCs hold significant potential for future clinical applications in nerve repair.