Preparation and Cytocompatibility Evaluation of PLLA-Graphene Composite Nanofibers

Composite nanofibers of poly(L-lactic acid)-graphene (PLLA-Gr) were prepared by electrospinning. The morphology and chemical structure of the electrospun PLLA-Gr fibrous mats were examined by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Raman Spectroscopy. The thermal, mechanical properties and wettability were characterized by means of DSC, TG, tensile tests and water contact angle measurement. Thereafter, cytocompatibility in terms of adhesion and proliferation of Schwann cells (SCs) on the composite nanofibrous scaffolds was evaluated by MTT assay and SEM observation. The results showed that Gr could be dispersed well in the PLLA nanofibers at a lower content. With the increasing of Gr content (m(Gr):m(PLLA)) from 0 to 2.0%, the resultant fiber diameters varied in a manner of thinning down at first and then increasing slightly. When m(Gr)∶m(PLLA) was increased to 1.0%, the diameter of PLLA-Gr nanofibers reached the minimum of (0.50±0.19) μm, with a corresponding tensile strength increased maximally by 50% compared to that from the electrospun pure PLLA nanofibers. Moreover, crystallinity of the nanofibrous PLLA-Gr membranes was governed by the content and dispersivity of Gr within the PLLA matrix. MTT assay at 1, 4 and 7 days showed that PLLA-Gr composite nanofibers could promote adhesion and proliferation of the Schwann cells. The electrospun nanofibrous PLLA-Gr is of good cytocompatibility.