Uptake and intracellular distribution of collagen-functionalized single-walled carbon nanotubes

Carbon nanotubes (CNTs) have shown great potential for biological and medical applications because of their intrinsic unique properties. However, applications of CNTs have been severely restricted by their super-hydrophobicity and easy aggregation in aqueous medium, which are related to cytotoxicity and other negative cellular effects. In this study, single-walled carbon nanotubes (SWCNTs) were functionalized with collagen (collagen-SWCNTs). The collagen-SWCNTs retained the inherent properties of SWCNTs and the suspension solution was stable for months. The cellular effects, uptake and intracellular distribution of the collagen-SWCNTs were investigated by using them for culture of bovine articular chondrocytes (BACs). The collagen-SWCNTs showed no obvious negative cellular effects and high amount of SWCNTs were internalized by cells. The internalized collagen-SWCNTs were distributed in the perinuclear region and retained in the cells for more than one week. Adsorption of SWCNTs by extracellular matrix (ECM) was shown to be an important step for cellular uptake of SWCNTs. The high stability, easy cellular uptake and long retention in cells of the collagen-SWCNTs will facilitate the biomedical and biotechnological applications of SWCNTs.