Tissue Engineering focuses on the repair and regeneration of damaged tissues using living cells and biomaterials. In the body, cells and tissues are highly organized at the micro- and nanoscale. Accordingly, micro- and nanotechnology tools can be used both to dissect how cells respond to their environment and to fabricate living tissues. In addition, cells interact to form tissues with properties that are greater than the sum of their parts. These 'emergent' properties in tissue biology can be studied with computational approaches as part of the new science of 'systems biology.