The present disclosure provides methods of making and applying metallized graphene fibers in bioelectronics applications. For example, platinized graphene fibers may be used as an implantable conductive suture for neural and neuro-muscular interfaces in chronic applications. In some embodiments, an implantable electrode includes a multi-layer graphene-fiber core, an insulative coating surrounding the multi-layer graphene-fiber core, and a metal layer disposed between the multi-layer graphene-fiber core and the insulative coating.