Peripheral Nerve Conduit: Materials and Structures

Abstract

Peripheral nerve injuries (PNIs) are the most common injury types to affect the nervous system. Restoration of nerve function after PNI is a challenging medical issue. Extended gaps in transected peripheral nerves are only repaired using autologous nerve grafting. This technique, however, in which nerve tissue is harvested from a donor site and grafted onto a recipient site in the same body, has many limitations and disadvantages. Recent studies have revealed artificial nerve conduits as a promising alternative technique to substitute autologous nerves. This Review summarizes different types of artificial nerve grafts used to repair peripheral nerve injuries. These include synthetic and natural polymers with biological factors. Then, desirable properties of nerve guides are discussed based on their functionality and effectiveness. In the final part of this Review, fabrication methods and commercially available nerve guides are described.

Aligned Fingolimod-Releasing Electrospun Fibers Increase Dorsal Root Ganglia Neurite Extension and Decrease Schwann Cell Expression of Promyelinating Factors

“…Several research groups are developing artificial nerve grafts that contain features that mimic the aligned organization of the native nervous system extracellular matrix (Arslantunali et al, 2014; Abbreviations: BDNF, brain-derived neurotrophic factor; BSA, bovine serum albumin; Cx32, connexin-32; DRG, dorsal root ganglia; GAP43, growth-associated protein 43; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; HFP, 1,1,1,3,3,3hexafluoro-2-propanol; HPLC, high-performance liquid chromatography; LCMS, liquid chromatography-mass spectrometry; MBP, myelin basic protein; mRNA, messenger ribonucleic acid; NCAM1, neural cell adhesion molecule 1; Oct6, octamer-binding factor 6; PBS, phosphate-buffered saline; PDGF-BB, plateletderived growth factor-BB; PDMS, polydimethylsiloxane; PLGA, poly(lactic-coglycolic acid); PLLA, poly-L-lactic acid; PMP2, peripheral myelin protein 2; qPCR, quantitative polymerase chain reaction; S1P, sphingosine-1-phosphate; SEM, scanning electron microscopy. Quan et al, 2016;Qian et al, 2018Qian et al, , 2019aHoushyar et al, 2019). Electrospinning can be used to generate a polymer scaffold with highly aligned topography.…”

Electrospinning Multilayered Scaffolds Loaded with Melatonin and Fe3O4 Magnetic Nanoparticles for Peripheral Nerve Regeneration

“…We also made microholes by a microneedle on the NGC for proper permeability, which was an essential factor for sufficient nutrients and oxygen exchange from the surrounding environment. [ 3 ]…”

“…Nerve guidance conduits (NGCs) have become a promising alternative to autologous nerve grafts and have been applied for nerve regeneration, along with continuous attempts of improvement including materials, structural design, and fabrication strategy. [ 2b,3 ] Natural derived materials such as collagen, chitosan, and hyaluronan have been widely used for constructing NGCs, but poor mechanical strength and nerve compression arising from fast degradation blocks their further application. [ 4 ] To handle these limitations, synthetic polymers gain frequent investigations, in which poly ε‐caprolactone (PCL) is an ideal biomaterial for tissue‐engineered scaffold due to its biocompatibility, biodegradability, flexible mechanical properties, and positive therapeutic effects on axonal regeneration and muscle functional recovery.…”

“…[ 6c,16 ] Besides, a satisfying NGC also calls for appropriate permeability for oxygen and metabolite. [ 1,3 ] Electrospinning has been used for fabricating biomimetic scaffold with incorporation of nanoparticles or supportive cells for enhanced performance; [ 17 ] nano‐scale structures and controllable mechanical properties have demonstrated positive effects on tissue engineering. [ 18 ] Thus, electrospinning technique is believed to be a feasible approach to design composite NGCs with multilayered structure.…”

Natural-Based Biomaterials for Peripheral Nerve Injury Repair

“…Peripheral nerve repair outcome after an injury is often poor, indeed it has been estimated that only 3% of patients recover sensibility while the motor function is recovered by less than 25% of patients (Houshyar et al, 2019).…”