Researchers have long said that microfluidics (microscopic plumbing) technology has the potential to shrink a laboratory to the size of a postage stamp or smaller for quicker, easier disease testing. What if the lab was actually in a postage stamp? It might look something like this gizmo developed by Harvard University researchers, who carved a treelike pattern from waterproof polymer and imprinted it onto a slip of paper. The paper wicks up a test fluid—in this case, an artificial urine solution—while keeping out dirt and other contaminants. Chemicals embedded in the tips of the paper branches change color depending on the sample's contents, such as proteins, which show up here as blue and yellow. Stamp collectors, go check out the scientists' microfluidics Web site.