Promotion of cell growth with magnetically enhanced single-walled carbon nanotubes

We demonstrate that purified and functionalized single walled carbon nanotubes (SWNTs) promote the growth of NIH3T3 mouse fibroblast cells under a magnetic field. The SWNTs are functionalized in acidic solutions by attaching carboxyl groups (–COOH) on their surfaces. Functionalized SWNTs (fSWNTs) exhibit a ferromagnetic property when dispersed in water. Cytotoxicity after the delivery of the fSWNTs into the cells is significantly reduced due to the complete removal of toxic metallic impurities during the functionalization process. The efficient uptake of the fSWNTs by the cells is confirmed through transmission electron microscopy (TEM). It is discovered that the growth of the NIH3T3 cells treated with the fSWNTs is enhanced by up to 25% than control cells when an external magnetic field is applied. Our findings may lead to the non-invasive and non-toxic drug delivery as well as targeted cell therapy with fSWNTs.