Electroconductive poly(3,4-ethylenedioxythiophene) (PEDOT) nanoparticle-loaded silk fibroin biocomposite conduits for peripheral nerve regeneration

Peripheral nerve injury (PNI) often clinically relies on the use of nerve grafts taken from the patient to establish a therapeutic effect, though secondary site of injury and morbidity have prompted the medical community to find alternative solutions. A new trend in the development of biomaterials arises in the form of electro-conductive biomaterials, especially for electrically active tissues such as the peripheral nerves. In this work, novel poly(3,4-ethylenedioxythiophene) PEDOT nanoparticles (PEDOT NPs) were synthetized via the mini-emulsion method and were combined with silk fibroin (SF) to create conduits for PNI repair. The synthesized PEDOT NPs-loaded SF conduits showed optimal properties for peripheral nerve substitution from the physico-chemical and biological point of view. They displayed excellent mechanical and conductivity performance with the tensile moduli reaching 6.61 ± 0.55 MPa and the conduits reaching 5.4 · 10^–4 S cm⁻¹, respectively. The conduits did not possess apatite-forming capacity, which were resistant to bending occlusions for angles up to 50° and to suturing. The developed conduits are promising as a novel biomaterial for applications in peripheral nerve regeneration; in vitro experiments showed that they did not allow BJ fibroblast infiltration, avoiding scar tissue formation in the lumen, and they did not show any toxic effect for Schwann cells.