1. A method for manipulating particles using a fluidized bed, the method comprising:rotating a chamber about a substantially horizontal axis to create a centrifugal force field, the chamber comprising an inlet and an outlet;
flowing a first stream containing a first media and particles into the chamber through the inlet, wherein flowing the first stream acts to create a force which opposes the centrifugal force;
forming a fluidized bed of particles in the chamber, wherein the forces substantially immobilize the particles in the fluidized bed by the summation of vector forces acting on the particles;
collecting the first media substantially without particles passing through the outlet of the chamber; then
manipulating the particles in the fluidized bed, wherein said manipulating is selected from the group consisting of removing, concentrating, diluting, exchanging media, harvesting, transferring, dispensing, transfecting, electroporating, separating, extracting, isolating, selecting, purifying, coating, binding, physically modifying, and altering the environment; and thereafter
removing the particles from the fluidized bed, wherein removing the particles comprises:
flowing a second stream into the chamber through the outlet, wherein flowing the second stream acts to create a force at least partially in the same direction as the centrifugal force field; and
collecting the particles passing through the inlet of the chamber.