Cellular uptake of single-walled carbon nanotubes in 3D extracellular matrix-mimetic composite collagen hydrogels

Carbon nanotubes (CNTs) exhibit intrinsic unique physical and chemical properties that make them attractive candidates for biological and biomedicine applications. An efficient cellular uptake of CNTs is vital for many of these applications. However, most of the cellular uptake studies have been performed with a two-dimensional cell culture system. In this study, cellular uptake of single-walled carbon nanotubes (SWCNTs) was investigated by using a three-dimensional cell culture system. Bovine articular chondrocytes cultured in SWCNTs/collagen composite hydrogels maintained their proliferation capacity when compared to the culture in collagen hydrogels. Ultraviolet-visible- nearinfrared spectroscopy analysis revealed a high amount of SWCNTs were internalized by cells. Confocal Raman imaging showed that most of the internalized SWCNTs were distributed in the perinuclear region. The results indicated that SWCNTs could be internalized by chondrocytes when SWCNTs were incorporated in the three-dimensional biomimetic collagen hydrogels.