Fabrication of electrospun silk fibroin scaffolds coated with graphene oxide and reduced graphene for applications in biomedicine

• Fibres coated with reduced graphene (SF/RG) became electronic conductors.
• Coated mats preserve the topography of the pure electrospun silk fibroin meshes.
• Cell proliferation was equal (Tukey, p > 0.05) on coated and non-coated mats.
• SF/RG is oxidised and reduced (− 0.4 V peak) as observed by cyclic voltammetry.
• SF/RG is able to sense physical and chemical conditions during reaction.

Silk fibroin and graphene are both promising biomaterials described in the bibliography. Hybrid scaffolds combining their properties could be attractive for tissue engineering applications. In this work, a new methodology to produce electrospun fibroin scaffolds coated with graphene materials is provided. The mechanical, electrical and electrochemical properties of the materials attained were characterised. The fibre diameters were measured (from 3.9 to 5.2 μm). The samples coated with reduced graphene were electronic conductors and electroactive in liquid electrolytes, showing maximum oxidation and reduction (around − 0.4 V peak). The chronoamperometric responses showed a reduction shoulder, pointing to the entrance of balancing cations from the solution by nucleation–relaxation: the reaction induced structural changes in the graphene. In order to check the biocompatibility of the materials, they were seeded with L929 fibroblasts. The excellent biocompatibility of silk fibroin meshes was maintained after coating with graphene, being the proliferation results equal in all the treatments 7 days after the seeding (Tukey, p > 0.05).The conductive and electroactive properties of meshes coated with reduced graphene allow the potential application of local electric fields or local ionic currents to cell cultures, biological interfaces or animal models without host response.

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