title: Comparison between two different methods of immobilizing NGF in poly(DL-lactic acid-co-glycolic acid) conduit for peripheral nerve regeneration by EDC/NHS/MES and genipin.
abstract: For surface modification and nerve regeneration, chitosan, followed by nerve growth factor (NGF), was immobilized onto the interior surface of poly (lactic acit-co-glycolic) conduits, using EDC/NHS/MES system (EDCs) and genipin (GP). Four new conduits were, therefore, obtained and named by immobilizing order-EDCs/EDCs, GP/EDCs, EDCs/GP, and GP/GP groups. The immobilized methods used were evaluated and compared, respectively. The researchers found that the EDCs- and GP-cross-linked chitosan displayed higher hydrophilic than pure poly (DL-lactic acid-co-glycolic acid) (PLGA) in water contact angle experiment, which meant the cell compatibility was improved by the modification. Scanning electron microscopic observations revealed that the GP-cross-linking of chitosan greatly improved cell compatibility while cultured rat PC12 cells were flatter and more spindle-shaped than EDCs-cross-linked chitosan. The results concerning the GP-cross-linked chitosan revealed significant proliferation of the seeded cells relative to pure PLGA films, as determined by counting cells and MTT assay. The NGF was released from the modified conduits in two separate periods--an initial burst in 5 days and then slow release from day 10 to day 40. The GP/EDCs group had the highest NGF value among all groups after the 5th day. Finally, the controlled-release conduits were used to bridge a 10 mm rat sciatic nerve defect. Six weeks following implantation, morphological analysis revealed the highest numbers of myelinated axons in the midconduit and distal regenerated nerve in GP/EDCs group. Therefore, the results confirm that GP/EDCs groups with good cell compatibility and effective release of NGF can considerably improve peripheral nerve regeneration.
authors.affiliation: Department of Chemical Engineering, National Chung Hsing University, Taichung, Taiwan, Republic of China.
authors.forename: Shu-Chih
authors.initials: SC
authors.lastname: Hsieh
authors.forename: Cheng-Ming
authors.initials: CM
authors.lastname: Tang
authors.forename: Wen-Tao
authors.initials: WT
authors.lastname: Huang
authors.forename: Ling-Ling
authors.initials: LL
authors.lastname: Hsieh
authors.forename: Chun-Mei
authors.initials: CM
authors.lastname: Lu
authors.forename: Chen-Jung
authors.initials: CJ
authors.lastname: Chang
authors.forename: Shan-hui
authors.initials: SH
authors.lastname: Hsu
mesh_terms: D017738:Alkanesulfonic Acids / Q000378:metabolism*; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D005022:Ethyldimethylaminopropyl Carbodiimide / Q000378:metabolism*; D048091:Guided Tissue Regeneration / Q000295:instrumentation / Q000379:methods; D020007:Implants, Experimental; D057889:Iridoid Glycosides / Q000378:metabolism*; D039823:Iridoids; D019344:Lactic Acid / Q000737:chemistry*; D008297:Male; D008422:Materials Testing; D009025:Morpholines / Q000378:metabolism*; D020932:Nerve Growth Factor / Q000737:chemistry* / Q000378:metabolism; D009416:Nerve Regeneration / Q000502:physiology*; D016716:PC12 Cells; D010525:Peripheral Nerves / Q000502:physiology; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D051381:Rats; D017207:Rats, Sprague-Dawley; D013388:Succinimides / Q000378:metabolism*; D013499:Surface Properties
chemical_list: D017738:Alkanesulfonic Acids; D001672:Biocompatible Materials; D057889:Iridoid Glycosides; D039823:Iridoids; D009025:Morpholines; D013388:Succinimides; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; C004550:2-(N-morpholino)ethanesulfonic acid; D019344:Lactic Acid; D020932:Nerve Growth Factor; C007834:genipin; C001426:N-hydroxysuccinimide; D005022:Ethyldimethylaminopropyl Carbodiimide