Tubular Nerve Guide and Epineurial Repair: Comparison of Techniques for Neurorrhaphy

In order to improve the guidance potential of a nerve entubulation bridging device, highly aligned textures were formed on the inner surface of semipermeable hollow fiber membranes (HFMs) during the wet phase inversion process. By precisely controlling the fabrication parameters, such as polymer solution flow rate, coagulant solution flow rate, and the air-gap distance, also called drop height, different-sized aligned grooves can be fabricated on the inner surface of HFMs. Preliminary studies using in vitro dorsal root ganglion (DRG) regeneration assay showed that both the alignment and outgrowth rate of regenerating axons increased significantly on HFMs with aligned textures compared to those on HFMs with a smooth inner surface. Studies in progress are evaluating axonal outgrowth and regeneration using in vivo sciatic-nerve and spinal-cord-injury models.

Section: Discussionmentioning

confidence: 99%

Fabrication of semipermeable hollow fiber membranes with highly aligned texture for nerve guidance

Zhang

Wen

2005

“…6 -14 Experimental work with animals was first reported using decalcified bone as a tube. 15 Later, work on biomaterials such as collagen, 16 -20 polytetrafluoroethylene, 21 silicon, 19,22 polyethylene, [23][24][25] poly-L-lactic acid/caprolactone, 12,26 -30 polyglycolide, 31 poly(L-lactide-co-glycolide) (PLGA), 32,33 collagen-polyglycolide, 34 and poly(phosphoester) 4,5 as nerve guide…”

Section: Introductionmentioning

confidence: 99%

Peripheral nerve regeneration by microbraided poly(L‐lactide‐co‐glycolide) biodegradable polymer fibers

Bini

Gao

et al. 2003

155

Tiny tubes with fiber architecture were developed by a novel method of fabrication upon introducing some modification to the microbraiding technique, to function as nerve guide conduit and the feasibility of in vivo nerve regeneration was investigated through several of these conduits. Poly(L-lactide-co-glycolide) (10:90) polymer fibers being biocompatible and biodegradable were used for the fabrication of the conduits. The microbraided nerve guide conduits (MNGCs) were characterized using scanning electron microscopy to study the surface morphology and fiber arrangement. Degradation tests were performed and the micrographs of the conduit showed that the degradation of the conduit is by fiber breakage indicating bulk hydrolysis of the polymer. Biological performances of the conduits were examined in the rat sciatic nerve model with a 12-mm gap. After implantation of the MNGC to the right sciatic nerve of the rat, there was no inflammatory response. One week after implantation, a thin tissue capsule was formed on the outer surface of the conduit, indicating good biological response of the conduit. Fibrin matrix cable formation was seen inside the MNGC after 1 week implantation. One month after implantation, 9 of 10 rats showed successful nerve regeneration. None of the implanted tubes showed tube breakage. The MNGCs were flexible, permeable, and showed no swelling apart from its other advantages. Thus, these new poly(L-lactide-co-glycolide) microbraided conduits can be effective aids for nerve regeneration and repair and may lead to clinical applications.

“…5,8 Attempts in creating suitable alternatives to address the limitations associated with the use of nerve autografts has produced a wide array of tissue engineered nerve guides (TENGs) to bridge the transected nerve. 7 An assortment of biomaterials such as collagen, 9 poly (L-lactide), 10 polyamides, 11 poly (phosphoesters), 12 and poly (ethylene) 13 have been used in combination with numerous processing techniques to fabricate synthetic alternatives, which can provide a physical substrate for the regenerating neural defect. 14…”

Section: Introductionmentioning

confidence: 99%

Fabrication and characterization of biomimetic multichanneled crosslinked‐urethane‐doped polyester tissue engineered nerve guides

Tran

Choy

Cao

et al. 2013

Biomimetic scaffolds that replicate the native architecture and mechanical properties of target tissues have been recently shown to be a very promising strategy to guide cellular growth and facilitate tissue regeneration. In this study, porous, soft, and elastic crosslinked urethane-doped polyester (CUPE) tissue engineered nerve guides were fabricated with multiple longitudinally oriented channels and an external non-porous sheath to mimic the native endoneurial microtubular and epineurium structure, respectively. The fabrication technique described herein is highly adaptable and allows for fine control over the resulting nerve guide architecture in terms of channel number, channel diameter, porosity, and mechanical properties. Biomimetic multichanneled CUPE guides were fabricated with various channel numbers and displayed an ultimate peak stress of 1.38 ± 0.22 MPa with a corresponding elongation at break of 122.76 ± 42.17 %, which were comparable to that of native nerve tissue. The CUPE nerve guides were also evaluated in vivo for the repair of a 1 cm rat sciatic nerve defect. Although histological evaluations revealed collapse of the inner structure from CUPE TENGs, the CUPE nerve guides displayed fiber populations and densities comparable with nerve autograft controls after 8 weeks of implantation. These studies are the first report of a CUPE-based biomimetic multichanneled nerve guide and warrant future studies towards optimization of the channel geometry for use in neural tissue engineering.