Triple functionalisation of single-walled carbon nanotubes with doxorubicin, a monoclonal antibody, and a fluorescent marker for targeted cancer therapy

Single-walled carbon nanotubes (SWCNTs) have been identified as a transporter for anti-cancer drugs, as they are capable of penetrating mammalian cell membranes and allow for a high drug loading due to their nanoscale dimensions and high aspect ratio. In addition, they can assist the targeting of therapeutic agents to the desired site of action by conjugation to antibodies or ligands of cancer cell surface receptors, which increases the effectiveness of the treatment and reduces side effects. In this work, we present a method for the triple functionalisation of oxidised SWCNTs with the anti-cancer drug doxorubicin, a monoclonal antibody, and a fluorescent marker at non-competing binding sites. The proposed methodology allows for the targeted delivery of the anti-cancer drug to cancer cells and the visualisation of the cellular uptake of SWCNTs by confocal microscopy. We show that the complex is efficiently taken up by cancer cells with subsequent intracellular release of doxorubicin, which then translocates to the nucleus while the nanotubes remain in the cytoplasm.