Ultralong and highly axially aligned nerve guide conduits produced by electro-centrifugal spinning

The fabrication of nerve guide conduits (NGCs) with axially aligned fibers has been realized by electrospinning; however, the reported maximum length of such NGCs is limited to 2 cm which cannot repair a long injured peripheral nerve. In this context, a modified electro-centrifugal spinning (ECS) system is developed to produce ultralong and highly axially aligned NGCs. To this end, medical-grade poly(lactic-co-glycolic acid) PLGA with L-to-G ratios of 8/2, 7/3, and 5/5 loaded with antibiotic ciprofloxacin (CIP) are used to investigate the corresponding spinning mechanisms and drug release behaviors. Specifically speaking, first, the effects of chloroform/trifluoroethanol co-solvents and drug loading on the spinnability and fiber orientation of PLGA are systematically investigated, and tubular conduits are produced with the established method. Second, uniaxial tensile tests and cyclic compressive tests for the conduits with and without drug loading are conducted; PLGA conduits with an L-to-G ratio of 8/2 are further annealed to enhance their mechanical properties. Last, the drug release behavior of the conduits in vitro is studied. As a result, highly fiber-aligned NGCs with a length of over 10 cm, combined with excellent mechanical properties and well-controlled drug release features can be efficiently produced. Therefore, this work provides a practical strategy for producing NGCs with high efficiency.