Electroactive 3D printable poly(3,4-ethylenedioxythiophene)-graft-poly(ε-caprolactone) copolymers as scaffolds for muscle cell alignment

The development of tailor-made polymers to build artificial three-dimensional scaffolds to repair damaged skin tissues is gaining increasing attention in the bioelectronics field. Poly(3,4-ethylene dioxythiophene) (PEDOT) is the gold standard conducting polymer for the bioelectronics field due to its high conductivity, thermal stability, and biocompatibility; however, it is insoluble and infusible, which limits its processability into three dimensional scaffolds. Here, poly(3,4-ethylendioxythiophene)-graft-poly(epsilon-caprolactone) copolymers, PEDOT-g-PCL, with different molecular weights and PEDOT compositions, were synthesized by chemical oxidative polymerization to enhance the processability of PEDOT. First, the chemical structure and composition of the copolymers were characterized by nuclear magnetic resonance, infrared spectroscopy, and thermogravimetric analysis. Then, the additive manufacturing of PEDOT-g-PCL copolymers by direct ink writing was evaluated by rheology and 3D printing assays. The morphology of the printed patterns was further characterized by scanning electron microscopy and the conductivity by the four-point probe. Finally, the employment of these printed patterns to induce muscle cells alignment was tested, proving the ability of PEDOT-g-PCL patterns to produce myotubes differentiation.