The capture of magnetic colloids at flow regimes specific to the capillary blood vessels

Magnetic drug targeting (MDT) of tumors situated in the cavity of the human body is difficult because the magnetic field and its gradients decrease rapidly with the distance from the magnets. Here a dipolar magnetic device is used to investigate the magnetic capture of colloidal magnetic particles (MPs) in capillary tubes at flow velocities similar to that encountered in the capillary beds of tumours. The capture of MPs is influenced by the gradient of the magnetic field, the flow velocity, the particle concentration and their surface properties. This work shows the potential of MDT for targeting tumours positioned at medium distances from the surface of the body (e.g. head, neck, breast, hands and legs).