A new method for protein separation by the gold nanotubules membrane based on the immunoreaction between antibody and antigen was described. The gold nanotubules can be electrolessly plated within the pores of polycarbonate nanoporous filtration membranes. The capture antibody, bovine IgG, was modified onto the inner wall of An nanotubules by glutaraldehyde interlinking method. The transport behaviour of detecting antibody through the nanotubules modified with capture antibody was investigated. When the diameter of the nanotubule was much larger than the size of the antibodies, there was no obvious difference between the transport rates for the proteins studied here through nanotubules. When the diameter of the nanotubule was ca. 30 nm, the transport of the goat anti-cat antibody through the nanotubules membrane was slow. Compared with goat anti-cat IgG, goat anti-bovine antibody transported through nanotubules membrane faster due to the immunoreaction between goat anti-bovine antibody and bovine IgG modified onto the pores of the membrane and the separation efficiency was 5.6. The results indicated that the gold nanotubule membranes showed good separating capability for protein without the loss of activity of the antibodies. (c) 2007 Published by Elsevier B.V.