Abstract: A bindable target such as a bacterial cell, virus, or molecule is captured from a liquid by contacting the liquid with magnetically attractable particles have an affinity for the target, and causing said particles to move repeatedly through said liquid to at least one solid support zone by attractive magnetic forces to capture the target onto said particles. The particles may be ferromagnetic, paramagnetic or superparamagnetic particles and may bear antibody, antibody binding fragments, a substance having an epitope capable of reacting in a specific manner with an antibody, an aptamer, a nucleic acid sequence or a nucleic acid analogue sequence, biotin, avidin or streptavidin.