Discrete, Oxidized Multi-Walled Carbon Nanotubes for Efficient Plasmid DNA Transfection

Background Carbon nanotubes have been identified as a possible plasmid and drug delivery method but are not developed enough to be as effective compared to other commercial methods such as lipid nanoparticles, electroporation and viral particles due to cytotoxicity and non-competitive transfection rates. Results Here, a stable dispersion of discrete, oxidized multi-walled carbon nanotubes (Fig. 1) was developed (do-MWCNT) using a lipid-like surfactant, DSPE-PEG-NH ₂ 2000 MW, and a cationic polymer 270k MW bPEI, that demonstrate better transfection-related gene expression with less cytotoxicity than commercially available lipid nanoparticles. The stable dispersion was then used to deliver a plasmid of 8.78kb with expression measured via qPCR that was comparable to Lipofectamine 3000. Analogous studies with discrete functionalized single wall carbon nanotubes showed further improvements with cell health. Conclusion Carbon nanotubes are capable of comparable transfection to lipid nanoparticles only after plasmid DNA is incubated with a dispersion for an extended period of time compared to lipid nanoparticles, 96 hours. This implies the limiting mechanism of nanotube transfection is pDNA binding. The novelty of single walled carbon nanotubes is also demonstrated by matching the surface surfactant conditions between the single and multi-walled carbon nanotube dispersions. It is further implied that the optimal geometry of carbon nanotube for transfection has yet to be explored.