Carbon Nanotube Meshes for Separating Proteins Electrophoretically

We report the development of a simple microfluidic device, which uses a carbon nanotube (CNT) membrane (CNTM) to separate two proteins based on their molecular weights (MW). The device was fabricated by traditional microfabrication techniques and chemical vapor deposition (CVD). Protein A (MW= 42 kDa) and aprotinin (MW= 6.5 kDa) were flowed through the CNTM in separate identical electrophoresis runs. The larger protein was observed to accumulate ahead of the CNTMs, whereas in the case of the smaller protein, no accumulation was observed, indicating that the buildup was due to the larger size of the higher MW protein. Electrophoresis on protein mixtures of 1) protein A and aprotinin and 2) protein A and lysozyme (MW= 17 kDa) was also performed and it was observed that only Protein A formed bands, wheras, the smaller proteins did not.