Novel magnetic bovine serum albumin imprinted polymers with a matrix of carbon nanotubes, and their application to protein separation

Novel magnetic multi-walled carbon nanotubes@Fe3O4 molecularly imprinted polymers (MWNTs@Fe3O4-MIPs) intended for bovine serum albumin (BSA) recognition were successfully developed. The MWNTs@Fe3O4-MIPs were characterized with scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Scanning electron microscopy images showed that the Fe3O4 nanoparticles (diameter: 50-60 nm) were coated with a layer of MIPs with an average thickness of 25-30 nm. The magnetic material was easily dispersed and retrieved through the application of an external magnetic field. Adsorption experiments showed that the estimated maximum amount of BSA that could be adsorbed onto the MWNTs@Fe3O4-MIPs was 52.8 mg/g, and the time taken to reach equilibrium was about 40 min. Meanwhile, the MWNTs@Fe3O4-MIPs exhibited excellent selectivity towards (i.e., recognition of) BSA. The feasibility of the use of the MWNTs@Fe3O4-MIPs as a solid-phase extraction (SPE) sorbent was evaluated, and the results showed that the MWNTs@Fe3O4-MIPs were able to separate the template protein BSA from a binary protein solution. The proposed sorbent based on MWNTs@Fe3O4-MIPs for BSA separation exhibited satisfactory recoveries ranging from 92.0% to 97.3% in real samples. It was also successfully used for the purification of BSA from bovine calf serum.