Date Published: October 15, 2017
Author(s): Anne Géraldine Guex, Jennifer L. Puetzer, Astrid Armgarth, Elena Littmann, Eleni Stavrinidou, Emmanuel P. Giannelis, George G. Malliaras, Molly M. Stevens.
Conjugated polymers have been increasingly considered for the design of conductive materials in the field of regenerative medicine. However, optimal scaffold properties addressing the complexity of the desired tissue still need to be developed. The focus of this study lies in the development and evaluation of a conductive scaffold for bone tissue engineering. In this study PEDOT:PSS scaffolds were designed and evaluated in vitro using MC3T3-E1 osteogenic precursor cells, and the cells were assessed for distinct differentiation stages and the expression of an osteogenic phenotype.
Tissue engineering approaches have been increasingly considered for the repair of non-union fractions, craniofacial reconstruction or large bone defect replacements. The design of complex biomaterials and successful engineering of 3-dimensional tissue constructs is of paramount importance to meet this clinical need. Conductive scaffolds, based on conjugated polymers, present interesting candidates to address the piezoelectric properties of bone tissue and to induce enhanced osteogenesis upon implantation. However, conductive scaffolds have not been investigated in vitro in great measure. To this end, we have developed a highly porous, electrically conductive scaffold based on PEDOT:PSS, and provide evidence that this purely synthetic material is a promising candidate for bone tissue engineering.
Conjugated polymers, in particular poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), have been numerously reported as potential candidates for biomedical applications and it has been hypothesised that they would present an ideal substrate for the growth and electrical stimulation of various cell types, most prominently osteogenic cells . Actual long term in vitro studies and evaluations of PEDOT:PSS as osteoinductive scaffolds are far fewer than the amount of published studies on material characterisation in other fields . To the best of our knowledge, this is the first report of the differentiation of osteogenic precursor cells into mature, mineralised osteoblasts on a porous PEDOT:PSS scaffold.
We could demonstrate the development of a highly porous, conductive scaffold based on PEDOT:PSS that supported the differentiation of pre-osteogenic precursor cells (MC3T3-E1) into mature osteoblasts.
Highly porous, conductive scaffolds were produced by freeze drying a PEDOT:PSS dispersion. Scaffolds present high pore interconnectivity and a median pore diameter above 50 µm, allowing for cell infiltration and matrix deposition within the void space. We could demonstrate that PEDOT:PSS is suitable as a scaffold for bone tissue engineering, indicated by the differentiation of osteogenic precursor cells (MC3T3-E1) into osteocalcin positively stained osteoblasts that express significantly enhanced levels of ALPL, RUNX2 and COL1A1 and deposit mineralised ECM.