Synthesis and Characterization of Polyaniline-based Electroconductive Scaffolds and Investigation of Their Influence on Stem Cell Behavior

Abstract

Introduction: Electrical stimulation (ES) is a process in which cells cultured on the prepared electro-conductive scaffold. The ES process has been applied on different cell types including nervous, cardio-vascular, muscular, and stem cells. This process application is going to expanding in tissue engineering. Functional parameters of cells like proliferation, maturation, and differentiation has been reported to be improve by the ES. A range of biomaterials based on inherently electro-conductive polymers (IEPs) are developed for hosting of different cell types and applying the ES. Objective: The aim of this study was to synthesize and characterization of poly aniline – sulfonated cyclodextrin (PANI/SCD) inclusion complex. The PANI/SCD was applied to treat rabbite mesenchymel stem cells (rbMSCs) with the ES process. Also, the effect of the ES process on bioavailability of the rbMSCs was investigated. Methods: The PANI/SCD inclusion complex was synthesized using interfacial oxidative method in which the PANI and SCD with equal concentration were dissolved in organic and aqueous phases, respectively. Yielded powder was characterized using different methods including FT-IR, 1HNMR, XRD, SEM, and electrochemical impedance spectroscopy (EIS). Prepared PANI/SCD powder then, was compressed to form a disk with diameter of 15mm. The rbMSCs were cultured on the PANI/SCD disks for a week. Cell morphology was studied by FE-SEM micrographs. Cell biocompatibility of the material was investigated using MTT analysis. Finally, the cells were stimulated using a 100mV.mm-1 electrical potential for three time a day and each time for 20 minutes. The ES process was done using a commercial dry cell in a 6-well late. Results and discussion: using an interfacial polymerization approach. The effect of some parameters on reaction yield were investigated. The optimum condition was found with equal concentration of components and in presence of HCL as the dopant. The synthesized inclusion polymer was characterized using different analytical methods. The electrical conductivity of the PANI/SCD scaffold was equal to 2.23 µS.cm-1 in dedoped form. Obtained conductivity is satisfying for a dedoped polymer and shows the sulfonic group in SCD successfully acted as an internal dopant. An obvious improvement in the cell morphology was observed because of the ES process. The ES process has been shown to be a potential alternative for different growth factors in the structure of scaffolds. This process significantly improved the bioavalability, cell population coverage on the scaffold and apoptotic behaviour of the rbMSCs. Obtained results also bold the potential(s) of the ES in regenerative medicine and tissue engineering. Apoptotic behaviour of the rbMSCs was shown to be improved under the ES condition. The percentage of the cells in early and late apoptosis were reduced to 13.7% and 2.30%, respectively under the ES conditions. In conclusion, we prepared a semi self-doped polymer for applying the ES process on the rbMSCs. Based on the obtained results, we successfully showed that the sunthesized PANI/SCD polymer is able to both hosting the cells and treating them by electricity. Also, we showed that the ES process improves the functions of the rbMSCs, cultured on the prepared PANI/SCD scaffold.