title: Manufacture of porous polymer nerve conduits through a lyophilizing and wire-heating process.
abstract: We have developed a method for nerve tissue regeneration using longitudinally oriented channels within biodegradable polymers created by a combined lyophilizing and wire-heating process. This type of cell-adhesive scaffold provides increased area to support and guide extending axons subsequent to nerve injury. Utilizing Ni-Cr wires as mandrels to create channels in scaffold increased safety, effectiveness, and reproducibility. The scaffolds tested were made from different biodegradable polymers, chitosan and poly(D,L-lactide-co-glycolide) (PLGA), because of their availability, ease of processing, low inflammatory response, and approval by the FDA. According to our experimental results, the high permeability and the characteristic porous structure of chitosan proved to be a better material for nerve guidance than PLGA. The scanning electron micrographs revealed that the scaffolds were consistent along the longitudinal axis with channels being distributed evenly throughout the scaffolds. There was no evidence to suggest merging or splitting of individual channels. The diameter of the channels was about 100 mum, similar to the 115 micromameter of the Ni-Cr wire. Regulating the size and quantity of the Ni-Cr wires allow us to control the number and the diameter of the channels. Furthermore, the neutralizing processes significantly influenced the porous structure of chitosan scaffolds. Using weak base (NaHCO(3) 1M) to neutralize chitosan scaffolds made the porous structure more uniform. The innovative method of using Ni-Cr wires as mandrels could be easily tailored to other polymer and solvent systems. The high permeability and the characteristic porous structure of chitosan made it a superior material for nerve tissue engineering. These scaffolds could be useful for guiding regeneration of the peripheral nerve or spinal cord after a transection injury.
authors.affiliation: Institute of Biomedical Engineering, College of Engineering, College of Medicine, National Taiwan University, Taipei, Republic of China.
authors.forename: Yi-Cheng
authors.initials: YC
authors.lastname: Huang
authors.forename: Yi-You
authors.initials: YY
authors.lastname: Huang
authors.forename: Chun-Chieh
authors.initials: CC
authors.lastname: Huang
authors.forename: Hwa-Chang
authors.initials: HC
authors.lastname: Liu
mesh_terms: D020341:Absorbable Implants; D001369:Axons / Q000378:metabolism; D001672:Biocompatible Materials / Q000737:chemistry*; D048271:Chitosan / Q000737:chemistry; D002857:Chromium / Q000737:chemistry; D005612:Freeze Drying; D048091:Guided Tissue Regeneration / Q000379:methods*; D006358:Hot Temperature; D007249:Inflammation; D019344:Lactic Acid / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D009416:Nerve Regeneration; D009417:Nerve Tissue; D009532:Nickel / Q000737:chemistry; D011091:Polyesters / Q000737:chemistry; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry*; D019736:Prostheses and Implants; D023822:Tissue Engineering
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; D011108:Polymers; D002857:Chromium; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D009532:Nickel; D048271:Chitosan