ted trapping of polystyrene spheres, and of various types of living cells: mouse fibroblast (NIH-313), yeast (Saccharomyces cerevisae), and algae (Chlamydomonas reinhardtii). The trapped particle and location of the magnetic trap can be translated in three dimensions by independent manipulation of the magn

ransduction of energy by microorganisms. We use the power produced by eukaryotic flagella in intact cells of the unicellular, photosynthetic algae Chlamydomonas reinhardtii to transport loads in microfluidic networks. These motile microorganisms -- which we refer to in this context as "microoxen" -- move mi