(293b) Multiwall Carbon Nanotubes (MWCNTs) Coating of Polyethylene Terephthalate (PET) Fibrous Matrices for Enhanced 3-D Cell Cultures and Functions

Much effort has been devoted to developing 3-D scaffolds for cell culture in tissue engineering. Polyethylene terephthalate (PET) fibrous materials have advantages, including high specific surface area and high porosity, over spongeous scaffolds and microcarriers, and have been widely used as 3-D scaffolds in immobilizing and culturing various types of cells. Carbon nanotubes with unique electric and biochemical properties can facilitate cell adhesion, protein adsorption and cell differentiation. However, the carboxylated carbon nanotubes and surfactants, such as sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (SDBS), modified carbon nanotubes exhibited toxic effects on cells. In this study, nonwoven PET fibrous matrices were uniformly coated with gelatin-modified multiwall carbon nanotubes (MWCNTs), which provided unique biochemical and electric characteristics without impairing the bioactivity of cells. GFP-cell lines including CHO, murine embryonic stem (mES) and breast cancer cells cultured in the modified PET scaffolds showed improved adhesion and proliferation and different morphologies as compared to cells cultured in unmodified PET scaffolds. In general, cells were stretched and well spread on the surface of PET fibers coated with nanotubes, whereas cells in unmodified PET scaffolds were sporadically distributed and not well spread in the matrix. MWCNTs enhanced cell adhesion, due largely to the nano roughness, and also increased cell proliferation, which was online quantified using a fluorometer. Besides cell adhesion and proliferation, protein adsorption on the coated PET scaffolds and alkaline phosphatase activity (ALP) were also investigated. In addition, MWCNTs coating significantly increased the conductivity of the PET matrix, thus allowing its use as a 3-D scaffolding material in bone regeneration under the electric stimuli. The MWCNTs modified PET fibrous materials have good biocompatibility and can serve as functional biological scaffolds for tissue engineering.