Electrophoretic Transport of Biomolecules Through Carbon Nanotube Membranes

Electrophoretic transport of proteins across electrochemically oxidized multi-walled carbon nanotube (MWCNT) membranes has been investigated. Small charged protein, lysozyme, was successfully pumped across MWCNT membranes by electric field while rejecting larger bovine serum albumin (BSA). Transport of the lysozome was reduced by a factor of about 30 in comparison to bulk mobility and consistent with Rankin equation predictions for hindered diffusion. Mobilities between 0.33-1.4x10^-9 m2/V-s were observed and are approximately 10 fold faster than comparable ordered nanoporous membranes. Diffusion coefficients are orders of magnitude higher than other nanoporous systems due to minimal interactions with CNT graphitic surface. For mixtures of BSA and lysozyme complete rejection of BSA is seen with electrophoretic separations.