Graphene, as a promising biomaterial, has received great attention in biomedical fields due to its intriguing properties, especially the conductivity and biocompatibility. Given limited studies on the effects of graphene-based scaffolds on peripheral nerve regeneration in vitro and in vivo under electrical stimulation (ES), the present study was intended to systematically investigate how conductive graphene-based nanofibrous scaffolds regulate Schwann cell (SC) behavior including migration, proliferation and myelination, and PC12 cell differentiation in vitro via ES, and whether these conductive scaffolds could guide SC migration and promote nerve regeneration in vivo. Briefly, the reduced graphene oxide (RGO) was coated onto ApF/PLCL nanofibrous scaffolds via in situ redox reaction of the graphene oxide (GO). In vitro, RGO-coated ApF/PLCL (AP/RGO) scaffolds significantly enhanced SC migration, proliferation, and myelination including myelin-specific gene expression and neurotrophic factor secretion. The conditioned media of SCs cultured on AP/RGO scaffolds under ES could induce the differentiation of PC12 cells in a separate culture. In addition, PC12 cells cultured on the conductive AP/RGO scaffolds also showed elevated differentiation upon ES. In vivo implantation of the conductive AP/RGO nerve guidance conduits into rat sciatic nerve defects exhibited a similar healing capacity to autograft, which is the current gold standard in peripheral nerve regeneration. In view of the performance of AP/RGO scaffolds in modulating cell functions in vitro and promoting nerve regeneration in vivo, it is expected that the graphene-based conductive nanofibrous scaffolds would exhibit their potential in peripheral nerve repair and regeneration. STATEMENT OF SIGNIFICANCE: Despite the demonstrated capability of bridging the distal and proximal peripheral nerves, it remains a significant challenge with current artificial nerve conduits to achieve the desired physiological functions, e.g., the transmission of electrical stimuli. Herein, we explored the possibility of combining the conductive properties of graphene with electrospun nanofiber to create the electroactive biomimetic scaffolds for nerve tissue regeneration. In vitro and in vivo studies were carried out: (1) In vitro, the conductive nanofibrous scaffolds significantly promoted SC migration, proliferation and myelination including myelin specific gene expression and neurotrophicfactor secretion, and induced PC12 cell differentiation with electrical stimulation. (2) In vivo, the conductive nerve guidance conduit exhibited similar effects with the gold standard autograft. In view of the performance of this conductive scaffold in modulating the cell functions in vitro and promoting nerve regeneration in vivo, it is expected that the graphene-modified nanofibrous scaffolds will exhibit their potential in peripheral nerve repair and regeneration.

中文翻译：

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体外和体内电活性还原氧化石墨烯修饰的纳米纤维支架用于周围神经再生的研究。

石墨烯作为一种有前途的生物材料，由于其令人着迷的特性，特别是导电性和生物相容性，在生物医学领域引起了极大的关注。鉴于对石墨烯基支架在体外和体内在电刺激（ES）下对周围神经再生的影响的研究有限，本研究旨在系统研究导电石墨烯基纳米纤维支架如何调节雪旺细胞（SC）行为，包括体外通过ES迁移，增殖和髓鞘化以及PC12细胞分化，以及这些导电支架是否可以指导SC迁移并促进体内神经再生。简而言之，通过氧化石墨烯（GO）的原位氧化还原反应将还原的氧化石墨烯（RGO）涂覆到ApF / PLCL纳米纤维支架上。体外，涂有RGO的ApF / PLCL（AP / RGO）支架可显着增强SC迁移，增殖和髓鞘形成，包括髓鞘特异性基因表达和神经营养因子分泌。在ES下在AP / RGO支架上培养的SC的条件培养基可以在单独的培养物中诱导PC12细胞的分化。另外，在导电AP / RGO支架上培养的PC12细胞在ES上也显示出升高的分化。体内将导电的AP / RGO神经引导导管植入大鼠坐骨神经缺损显示出与自体移植相似的愈合能力，这是当前周围神经再生的金标准。鉴于AP / RGO支架在体外调节细胞功能并在体内促进神经再生的性能，预期基于石墨烯的导电纳米纤维支架将展示其在周围神经修复和再生中的潜力。意义声明：尽管已证明桥接远端和近端周围神经的能力，但对于当前的人工神经导管而言，要实现所需的生理功能（例如电刺激的传递）仍然是一项重大挑战。在本文中，我们探索了将石墨烯的导电特性与电纺纳米纤维相结合以创建用于神经组织再生的电活性仿生支架的可能性。进行了体外和体内研究：（1）在体外，导电纳米纤维支架显着促进了SC迁移，增殖和髓鞘形成，包括髓鞘特异性基因表达和神经营养因子分泌，并通过电刺激诱导PC12细胞分化。（2）在体内，传导性神经引导导管表现出与金标准自体移植相似的作用。考虑到该导电支架在体外调节细胞功能和促进体内神经再生的性能，预期石墨烯修饰的纳米纤维支架将在外周神经修复和再生中展现其潜力。