Bilayer Cylindrical Conduit Consisting of Electrospun Polycaprolactone Nanofibers and DSC Cross‐Linked Sodium Alginate Hydrogel to Bridge Peripheral Nerve Gaps

Abstract

Herein, a bilayer cylindrical conduit (P‐CA) is presented consisting of electrospun polycaprolactone (PCL) nanofibers and sodium alginate hydrogel covalently cross‐linked with N,N′‐disuccinimidyl carbonate (DSC). The bilayer P‐CA conduit is developed by combining the electrospinning and outer–inner layer methods. Using DSC, as a covalent crosslinker, increases the degradation time of the sodium alginate hydrogel up to 2 months. The swelling ratio of the hydrogel is also 503% during the first 8 h. The DSC cross‐linked sodium alginate in the inner layer of the conduit promotes the adhesion and proliferation of nerve cells, while the electrospun PCL nanofibers in the outer layer provide maximum tensile strength of the conduit during surgery. P‐CA conduit promotes the migration of Schwann cells along the axon in a rat model based on functional and histological evidences. In conclusion, P‐CA conduit will be a promising construct for repairing sciatic nerves in a rat model.

Hydrogels for Tissue Engineering: Addressing Key Design Needs Toward Clinical Translation

“…Electrospun hydrogels based on both natural polymers such as collagen, gelatin, dextran, alginate, HA, or chitosan as well as synthetic polymers such as POEGMA ( Xu et al, 2016 ) have been reported, with other synthetic polymers such as poly (ethylene oxide) (PEO), poly (vinyl pyrrolidone) (PVP), or poly (vinyl acetate) (PVA) also in some cases included to promote chain entanglement in the precursor polymer solution and thus nanofiber formation instead of particle sprays. Stiffer degradable polymers such as poly (ε-caprolactone) (PCL) may also be added to increase the mechanical strength of the porous hydrogel scaffold, a key challenge with electrospinning ( Koosha and Mirzadeh, 2015 ; Xu et al, 2016 ; Majidi et al, 2018 ; Wakuda et al, 2018 ; Askarzadeh et al, 2020 ). Table 1 summarizes different materials and methods used for electrospinning hydrogels.…”

An Up‐to‐Date Review on Alginate Nanoparticles and Nanofibers for Biomedical and Pharmaceutical Applications

“…[265] Likewise, core-shell PCL-alginate electrospun NFs were proposed as substitutes for peripheral nerves. [266] These composite NFs promoted water absorption and biological activity of the neural precursors, leading to fasttracking of the sciatic nerve repair in a rat model. The nearfield electrospinning of alginate was also demonstrated.…”

Natural-Based Biomaterials for Peripheral Nerve Injury Repair

“…Alginate is also used successfully as a conduit internal filler for growth factor delivery in nerve regeneration ( Ohta et al, 2004 ; Pfister et al, 2007b , 2008 ) and for molecule controlled release at various pH values ( Augst et al, 2006 ; Gao et al, 2009 ; Jeon et al, 2009 ). In particular, alginate as internal filler leaves no residue 4 months after surgery in a cat model of 50 mm gap sciatic nerve injury repaired with tubulation ( Sufan et al, 2001 ) and is also able to promote specifically adhesion and proliferation of nerve cells in rats with 10 mm sciatic nerve gap 7 weeks after surgery ( Askarzadeh et al, 2020 ).…”