Controlled oxygen plasma treatment of single-walled carbon nanotube films improves osteoblastic cells attachment and enhances their proliferation

The effects of oxidative treatment of single-walled carbon nanotubes (SWCNTs) on the adhesion and proliferation of human osteoblasts (SAOS-2) were investigated. The surface properties of SWCNTs after oxygen plasma treatment were characterized by contact angle measurement, scanning electron microscopy and Raman spectroscopy. The immunofluorescent staining of vinculin, actin filaments and nuclei was used to probe cell adhesion and growth on SWCNT films. Our results show that adhesion and proliferation of human osteoblasts cultivated on SWCNT films indeed depends on the degree of an oxidative treatment. As an optimal procedure was found the treatment with oxygen plasma for 5 min. In the latter case the osteoblasts form a confluent layer with pronounced focal adhesions throughout the entire cell body. The optimal conditions compromise the effect of hydrophilic character of SWCNT films and the level of damage of SWCNT surface.