Abstract: An apparatus includes a substrate having a top surface, a substantially regular array of raised structures located over the top surface, and a layer located on the top surface between the structures. Distal surfaces of the structures are farther from the top surface than remaining portions of the structures. The layer is able to contract such that the distal surfaces of the structures protrude through the layer. The layer is able to swell such that the distal surfaces of the structures are closer to the top surface of the substrate than one surface of the layer.

Abstract: The present invention provides an apparatus comprising a substrate and first and second disks. The disks are rotatably located over the substrate, each disk having an outer circumference with teeth thereon. The first disk is positioned to interleave one or more of its teeth with the teeth of the second disk. The substrate includes a channel with an exit port located near the teeth of one of the disks. Another apparatus comprises at least one disk rotatably located over a substrate and in a well of the substrate, the disk having an outer circumference with teeth thereon. The disk is positioned to provide a maximum distance of less than about 10 microns between each one the teeth and a nearest wall defining the well. The substrate includes a channel with an exit port located near the teeth of the disk.

Abstract: Provided is an apparatus. In one embodiment, this apparatus includes a substrate having a surface, and a plurality of nanostructures each having a first end and a second end, wherein the first end of each of the plurality of nanostructures is attached to the surface. At least a portion of the second ends of the plurality of nanostructures, in this embodiment, are bent toward one another to form two or more similarly configured clumps each including two or more nanostructures.