Multi-channel chitosan–polycaprolactone conduits embedded with microspheres for controlled release of nerve growth factor

• Published in: Reactive & functional polymers Vol. 73; no. 1; pp. 149 - 159
• Main Authors: Liao, Chunyan, Huang, Junchao, Sun, Shaofa, Xiao, Bo, Zhou, Nuo, Yin, Dengke, Wan, Ying
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01.01.2013; Elsevier
• Subjects: Applied sciences; Biological and medical sciences; Chitosan–polycaprolactone copolymer; Chitsoan microsphere; Controlled release; Exact sciences and technology; Medical sciences; Multi-channel conduit; Natural polymers; Nerve growth factor; Physicochemistry of polymers; Starch and polysaccharides; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Technology. Biomaterials. Equipments; Nerve growth factor; Multi-channel conduit; Chitsoan microsphere; Chitosan–polycaprolactone copolymer; Controlled release; Biological properties; Encapsulation; Graft copolymer; Biodegradability; Porous material; Caprolactone copolymer; Chitosan―polycaprolactone copolymer; Biomaterial; Microencapsulation; Manufacturing; Release; Molding; Tissue engineering; Filled polymers; Control release polymer; Stress strain relation; Mechanical properties; Experimental study; In vitro; Biological activity; Hydrolysis; Compressive stress; Chitosan derivatives; Morphology; Oside polymer; Microgel; Chitosan; Kinetics; Nervous tissue
• ISSN: 1381-5148
• DOI: 10.1016/j.reactfunctpolym.2012.09.008

Nerve growth factor (NGF)-loaded chitosan microspheres were prepared via emulsification method using sodium tripolyphosphate as a crosslinker. Some selected chitosan microspheres were embedded into chitosan–polycaprolactone (CH–PCL) multi-channel conduits that can potentially be used for long-gap nerve repair. PCL percentages in the CH–PCLs were optimized into a region changing from around 30 to 42wt.% while the porosity and average channel diameter of the resulting multi-channel conduits were selected as about 80% and 200μm, respectively. SEM images confirmed that the channels inside the conduits were longitudinally arrayed with an approximately parallel arrangement, and the NGF-loaded microspheres appeared to be embedded into the wall of channels without blocking. The compressive properties in wet state and in vitro degradation rates of CH–PCL multi-channel conduits were found to be mainly manipulated by the PCL content in the CH–PCLs whereas the cumulative amount of released NGF from the conduits could be independently regulated by altering the initial NGF load inside the embedded microspheres. The optimal microsphere-embedded CH–PCL multi-channel conduits with a dimension of around 6mm in outer diameter and 30mm in length were able to administrate bioactivity-preserved NGF release in a sustained and controlled manner without significant initial burst release, and the release rates of the conduits could be maintained with approximately linear characteristic over a period of time longer than 6weeks.