Electroconductive, flexible, and printable graphene nanoplate-carbon nanotube-polydimethylsiloxane composite collectors for three-dimensional conformal electrospinning

The three-dimensional (3D) nanofibrous structure demonstrates significant potential in tissue engineering and regenerative medicine. As electrospinning is typically conducted on metal substrates, the integration of a nanofibrous structure with complex 3D non-conductive substrates remains challenging. Therefore, we suggest graphene nanoplate-carbon nanotube-polydimethylsiloxane (GCP) composites as a collector for 3D conformal electrospinning on non-conductive substrates. To prepare electroconductive, flexible, and printable GCP composite collectors, we formulate a GCP ink that is compatible with dip coating and printing processes. Using the GCP ink enables the facile and versatile fabrication of GCP composite collectors on non-conductive substrates, including 3D substrates. By dip coating and printing the GCP ink on a polydimethylsiloxane (PDMS) and water-soluble polyvinyl alcohol (PVA) substrate, 3D or patterned GCP-PDMS composite collectors and hollow GCP composite collectors by removing the PVA substrate are achieved, respectively. Subsequent electrospinning on the GCP-PDMS and hollow GCP composite collector fabricated spatially controlled nanofiber mats with 3D ear and knee cartilage shapes, patterned and aligned configurations, and 3D blood-vessel shape. Finally, as a potential application of artificial ear-cartilage implants, we demonstrate the enhanced biocompatibility and flexibility of 3D nanofiber mat-coated GCP-PDMS composites.