In-vitro toxicity of carbon nanotube/polylysine colloids to colon cancer cells

Single-walled carbon nanotubes (SWCNTs) are thoroughly purified and dispersed in an aqueous solution of high molecular weight poly-L-lysine (pLlys). Human intestinal epithelial Caco-2/TC7 cells are incubated with the SWCNT dispersions in pLlys, and their effects on cell viability are studied by image flow cytometry. No significant changes are observed in the cell culture wells up to pLlys concentrations of 10 g mL-1. However, high mortality is detected at pLlys concentrations of 100 g mL-1. The presence of oxygen-free SWCNTs does not modify the effects of pLlys on cell cultures at any of the tested concentrations (£ 1 g mL-1). In addition, SWCNTs having an 8 wt.% of surface oxygen are tested with identical results. Thus, purified SWCNTs, even bearing oxygen functional groups, act as inert particles in the cell culture medium. This result supports the applicability of SWCNTs as carriers in pharmacological formulations against digestive tract diseases.This work was funded by the Spanish Ministry MINECO and the European Regional Development Fund under the projects PRI-PIBAR-2011-1 and ENE2013-48816-C5-5-R, and the Government of Aragon and the European Social Fund (DGA-ESF-T66 Grupo Consolidado and DGA-ESF-B61 Grupo Consolidado).Peer reviewe