Much like the checkout clerk uses a machine that scans the barcodes on packages to identify what customers bought at the store, scientists use powerful microscopes and their own kinds of barcodes to help them identify various parts of a cell, or types of molecules at a disease site. But their barcodes only come in a handful of "styles," limiting the number of objects scientists can study in a cell sample at any one time. Researchers at the Wyss Institute for Biologically Inspired Engineering at Harvard University have created a new kind of barcode that could come in an almost limitless array of styles - with the potential to enable scientists to gather vastly more vital information, at one given time, than ever before. The method harnesses the natural ability of DNA to self-assemble, as reported today in the online issue of Nature Chemistry.