Three-dimensional electrical conductive scaffold from biomaterial-based carbon microfiber sponge with bioinspired coating for cell proliferation and differentiation

Electrical responsive scaffolds are important for regulating adhesion, mitigation, and proliferation of electroactive cells in tissue engineering. Conventional approaches to fabricate suitable scaffolds with enhanced electrical conductivity require multiple steps including the surface coating of conductive polymers or the encapsulation of conductive fillers. In this work, a new type of three-dimensional porous carbon fiber sponge-based electrical conductive scaffold with a fiber diameter of 8.1 (+/- 2.1) mm was fabricated by one-step high-temperature carbonization at 800 degrees C from an abundantly available biomaterial - cotton. The as-carbonized cotton has a suitable pore size from several dozens to hundreds of micrometers, low toxicity, and good biocompatibility. Its hydrophilicity and biocompatibility were further modified by surface oxidation and polydopamine coating. The topological feature, surface functional groups, hydrophilicity, and electrical conductivity of the carbonized cotton were studied. The as-carbonized, oxidized, and polydopamine-coated scaffolds have electrical conductivities of 32.6, 44.9 and 128.2 S/m, respectively. The cytocompatibility and the effect of electrical stimulation on cell behavior were evaluated by cell culture with and without electrical stimulation. It was observed that the polydopamine coating significantly improved the hydrophilicity and cytocompatibility. The electrical stimulation accelerated cell proliferation and differentiation of nerve cells. This work demonstrated that carbonized biomaterial represents a promising material category that can be used for tissue engineering especially in electroactive tissues. (C) 2018 Elsevier Ltd. All rights reserved.