A Review of Bioactive Release from Nerve Conduits as a Neurotherapeutic Strategy for Neuronal Growth in Peripheral Nerve Injury

Table 1

Salient features of an ideal nerve conduit.

Conduit features and requirements	Importance and function	References
Mechanical attributes	(i) Should not bend, buckle, or kink postimplantation; (ii) Be able to maintain structural integrity to support tissue growth	[2, 16, 24]
	(i) Overly pliable conduits are unable to withstand pressure from growing and surrounding tissues; (ii) Rigid conduits may cause compression and damage to growing and surrounding tissues; For example, blood vessels and nerve stumps; (iii) Sufficient flexibility to withstand body movements, particularly at joint sites	[24, 25, 30]
Biodegradation rate	(i) Should degrade at a rate corresponding to tissue regeneration; (ii) Premature disintegration removes provision of support structure; (iii) Lengthy degradation may cause compression and inflammation of newly generated tissues	[30, 31]
Semipermeability	(i) Should allow exchange of oxygen and nutrients and elimination of waste products between internal and external environment of conduit; (ii) Prevent infiltration of inflammatory cells and fibrotic tissue; (iii) Prevent escape of neurotrophic growth factors secreted by damaged nerve stumps and from system	[16, 24, 30]
Physical and 3D guidance cues	(i) Cylindrical and channel-based structures for growth cone guidance; (ii) Prevent axonal misdirection during regeneration towards distal nerve	[15, 24, 29]
Ability to deliver growth factors or Schwann cells	(i) Enhancement of functional recovery and axonal regeneration; (ii) Important for neuronal survival and differentiation; (iii) Schwann cells for support of axon regeneration and remyelination	[22, 30, 32–35]
Processing requirements	Maintenance of stability during handling, sterilization, storage, and surgical procedures	[24]