Physiochemical and morphological dependent growth of NIH/3T3 and PC-12 on polyaniline-chloride/chitosan bionanocomposites

Abstract

Biomimetic scaffolds inspired by fields and forces of the natural environment of cells is essential in tissue engineering. This study reports on controlled growth of two model cell lines, NIH/3T3 (promiscuous, fibroblast) and PC-12 (electroresponsive, neural progenitor) cells, given electrical and topographical cues that were delivered from a bionanocomposite of polyaniline-chloride and chitosan (PAn-Cl/CHI). The conductivity and morphology of the scaffold were controlled by varying the wt% of PAn-Cl (0-50 wt%) in CHI and processing methods, air-drying (nanofeatured) versus lyophilization (microporous-reticulated), respectively. Bionanocomposites supported the growth of both cell types independent of the availability of receptor-mediated ligands (laminin). NIH/3T3 cells were less elongated on lyophilized (microporous-reticulated) and more conductive (higher wt% PAn-Cl) composites. PC-12 cells had higher viability and less aggregation when grown on conductive substrates. Air-dried bionanocomposites were more supportive of growth but not attachment of PC-12 cells, suggesting that processing of composites could provide an additional level of engineering control to alter the PC-12 cell attachment and growth. In general, PC-12 cells responded more distinctly and dramatically to the substrate properties than NIH/3T3 cells, supporting a clear role for electrical conductivity on neural cell behavior. Nerve growth factor(NGF)-induced differentiation of PC-12 cells resulted in extensive neurite extension in the presence of adsorbed laminin. In a substrate composition-dependent manner, extension and rate of neurite outgrowth were higher when cultured on the conductive substrates. Overall, this study demonstrates the suitability of conductive PAn-Cl/CHI scaffold to host different cell types and support their responses.

Keywords: Chitosan-bionanocomposites; Electrical-impedance; Laminin; NIH/3T3 cells; PC-12 differentiation; Polyaniline-nanofibers.