Studies on cytocompatibility of human dermal fibroblasts on carbon nanofiber nanoparticle-containing bioprinted constructs

Functional nanocomposite-based printable inks impart strength, mechanical stability, and bioactivity to the printed matrix due to the presence of nanomaterials or nanostructures. Carbonaceous nanomaterials are known to improve the electrical conductivity, osteoconductivity, mechanical, and thermal properties of printed materials. In the current work, we have incorporated carbon nanofiber nanoparticles (CNF NPs) into methacrylated gelatin (GelMA) to investigate whether the resulting nanocomposite printable ink constructs (GelMA-CNF NPs) promote cell proliferation. Two kinds of printable constructs, cell-laden bioink and biomaterial ink, were prepared by incorporating various concentrations of CNF NPs (50, 100, and 150 µg/mL). The CNF NPs improved the mechanical strength and dielectric properties of the printed constructs. The in vitro cell line studies using normal human dermal fibroblasts (nHDF) demonstrated that CNF NPs are involved in cell-material interaction without affecting cellular morphology. Though the presence of NPs did not affect cellular viability on the initial days of treatment, it caused cytotoxicity to the cells on days 4 and 7 of the treatment. A significant level of cytotoxicity was observed in the highly CNF-concentrated bioink scaffolds (100 and 150 µg/mL). The unfavorable outcomes of the current work necessitate further study of employing functionalized CNF NPs to achieve enhanced cell proliferation in GelMA-CNF NPs-based bioprinted constructs and advance the application of skin tissue regeneration.