Influence of carbon nanotube scaffolds on human cervical carcinoma HeLa cell viability and focal adhesion kinase expression

Five types of carbon nanotube (CNT) scaffolds were prepared by vacuum filtration of the dispersed single-wall carbon nanotubes (SWCNTs), acid-treated SWCNTs, multi-wall carbon nanotubes (MWCNTs), acid-treated MWCNTs, and amylose-wrapped SWCNTs in water onto porous poly(vinylidene chloride) membranes. The influence of these scaffolds on human cervical carcinoma HeLa cells was investigated by WST-1 assay, acridine orange/ethidium bromide double staining and 1,1′-dioctadecyl-3,3,3′,3′tetram-ethylindocarbocyanine perchlorate staining. The results indicated that the viability of HeLa cells cultured on these scaffolds decreased in the following order: amylose-wrapped SWCNTs > acid-treated MWCNTs > MWCNTs > acid-treated SWCNTs > SWCNTs. Cells cultured on SWCNTs and on acid-treated SWCNTs were found undergoing apoptosis with damaged cell membrane and condensed chromatin. The result of an immunocytochemical test showed that both “dot-like” and “dash-like” focal adhesion kinases (FAKs) mainly distributed at the periphery of cells cultured on SWCNTs, while “dot-like” FAKs distributed in the whole cell body of cells cultured on MWCNTs. We therefore hypothesize that FAK expression might play a key role in controlling cell viability for cells cultured on CNT scaffolds.