I think I would use dialysis. In my opinion, that method that will afford little loss of antibody. A spin column is much faster but will probably have lower yield. I would use a 0.1-0.5 ml Slide-a-lyzer cassette with 10K or 20K molecular weight cutoff, or something equivalent.

Another way would be to use a centrifugal ultrafiltration unit, such as a Microcon YM-10, which holds up to 400 µl. After concentrating the 200 µl sample down to about 20 µl, redilute it with reaction buffer to 400 µl. This reduces the gentamicin concentration about 20-fold Concentrate it again in the same unit to about 20 µl and redilute it again to 400 µl. The final gentamicin concentration will be reduced 400-fold from the start and will therefore be roughly equimolar with the antibody. One more round of concentration and dilution and the gentamicin concentration will be negligible.

Hi,

Using magnetic nanoparticles and pull-down assays for targeted antibody may be an option for this purpose. Additional clean up steps can confirm that you get aminoglycoside-free antibody isolates. I guess protein A or G ligand attached magnetics will help for antibody enrichment and getting rid of gentamycin since they have an affinity to Fc regions...

Good luck,

Emir.

I've used 40kDa Zeba Columns very successfully with very little loss.