Multiwalled carbon nanotube-coated polyethylene terephthalate fibrous matrices for enhanced neuronal differentiation of mouse embryonic stem cells.

The next-generation of tissue scaffolds should incorporate 3-D structures with nanofeatures. Fibrous polyethylene terephthalate (PET) matrices have been widely studied as tissue engineering scaffolds, but their performance is limited by the lack of nanotopography. Carbon nanotubes can provide nanoscale structures similar to those present in natural extracellular matrices in vivo, but are difficult to use as 3-D scaffolds for tissue engineering. In this study, multiwalled carbon nanotubes (MWCNTs) were used to coat and provide nanofeatures on the surface of PET membranes and fibers. The effects of MWCNTs on the cellular functions of mouse embryonic stem (mES) cells cultured on the nanoengineered PET surface and 3-D scaffolds were investigated. In general, MWCNTs promoted cell adhesion and proliferation of mES cells while maintaining excellent cell viability in the growth medium. Neuronal differentiation was also significantly enhanced when cells were cultured in the differentiation medium. Different cell morphologies were observed in the presence of MWCNTs. Cells were stretched and well spread out in MWCNT-coated PET scaffolds, whereas cells were sporadically distributed in non-coated PET scaffolds. Furthermore, more filopodia were formed in MWCNT-coated PET matrices, suggesting increased interactions between scaffolds and cells. Also, neuronal cells differentiated from mES cells in the 3-D nanoengineered PET scaffolds formed extensive nerve networks around each fiber and neurite bridges between fibers. These findings suggest that MWCNTs can provide nanofeatures on PET fibrous matrices and enhance their performance as 3-D nanoengineered tissue engineering scaffolds.