Highly electroconductive multiwalled carbon nanotubes as potentially useful tools for modulating calcium balancing in biological environments

Aiming to explore the mechanisms modulating cell-carbon nanotube interactions, we investigated whether Ca2+ ion balancing between intra- and extracellular environments could be affected by multiwalled carbon nanotubes (MWCNTs). We analyzed the effects induced by two different kinds of MWCNTs (as prepared and annealed at 2400°C) on the intracellular Ca2+ ion levels in rat electrically sensitive cells and on the intercellular junction integrity of rat adenocarcinoma colon cells and platelet aggregation ability, which depend on the Ca2+ concentration in the medium. MWCNTs, purified by annealing and more electroconductive as compared to nonannealed MWCNTs, affected Ca2+ ion balancing between extra- and intracellular environments and induced changes on Ca2+ ion-dependent cellular junctions and platelet aggregation, behaving as the calcium chelator ethylene glycol tetraacetic acid. This could be due to the sorption of cationic Ca2+ ions on CNTs surface because of the excess of negatively charged electrons on the aromatic units formed on MWCNTs after annealing.From the Clinical EditorThe authors investigated whether Ca2+ ion balance between intra- and extracellular space can be modulated by multiwalled carbon nanotubes (MWCNTs). Annealed nanotubes induced changes on Ca2+ dependent cellular junctions and platelet aggregation, behaving similary to ethylene glycol tetraacetic acid, an established calcium chelator.

Graphical AbstractPurified by annealing and electro-conductive MWCNTs affect Ca++ ion balancing between extra and intracellular environments, inducing: i) an early increase in cytosolic Ca++ ion levels in electrically sensitive neuronal-derived cells, possibly due to Ca++ mobilization from the intracellular storage compartments; ii) disruption of Ca++ ion-dependent cell-cell junction integrity; iii) decreased Ca++ ion-dependent platelet aggregation ability. These effects are likely due to the sorption of the cationic Ca++ ions on carbon nanotube surface because of the excess of negatively charged electrons on the aromatic units formed on MWCNTs after annealing.Figure optionsDownload high-quality image (159 K)Download as PowerPoint slide