The Effect of Electrical Stimulation on Growth and Proliferation of Neural Cells Using Conductive Nanofibrous Scaffolds

Nowadays, the use of scaffolds in tissue engineering to repair and regenerate human lesions, including nervous injuries has been widely considered. Also, nanofibrous scaffolds due to their structural similarity with the extracellular matrix (ECM) in the body are found to be suitable substrates for cell growth. Therefore, the main focus of the present work is on the production of conductive nanofibrous scaffolds for neural cell culture and their electrical stimulation performance. Two biocompatible polymers including polycaprolactone (PCL) and poly(lactic-co-glycolicacid) (PLGA) were used as main materials, and polyaniline (PANI) was applied as a conductive polymer to create conductivity in the substrates. After determination and optimization of the electrospinning process factors, 4 types of nanofibrous scaffolds with 4 levels of conductive polymer (0%, 1%, 10% and 18%) were prepared. To investigate the effect of scaffolds' conductivity and electrical stimulation on the nerve cells behavior, a plate with steel electrodes was designed to apply electrical field to the scaffolds during cell culture experiments. SEM, Dino-Lite digital microscopy, Potentiostat-Galvanostat and 3-(4,5-dimethylthiazed-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were used to study the properties of scaffolds including hydrophilicity, conductivity, fiber diameter and the results of cell culture. By investigation of the physical properties of the scaffolds it was shown that increasing the amount of PANI in scaffolds causes significant drop in the fiber diameter and hydrophilicity. In cell culture experiment, shape and proliferation of nerve cells were studied. MTT assay and SEM images showed that electrical stimulation, proportional to the amount of polyaniline, enhanced neurite outgrowth compared to the scaffolds that were not subjected to electrical stimulation. Furthermore, proliferation of cells on conductive scaffolds (by 10% v/w of PANI) increased and subsequently the cell proliferation decreased with increasing conductive polymer content due to its toxicity.