About 2 decades ago, with the invention of the i-STAT® System (Abbott Laboratories), clinical laboratories began moving blood and serum through microchannels for efficient point-of-care diagnostics. To produce the most precise microchannels, valves, and chambers ≤100 μm wide, researchers turned to silicon. But silicon is expensive, and throughout the last decade, scientists have searched for other materials that could be put to use. Although many have claimed that their inventions could serve as cheaper, simpler diagnostic tools, few have pushed the potential of these new technologies to serve the developing world, where low-cost, simple-to-use diagnostic tools can be game-changing. Enter George M. Whitesides, a professor of chemistry at Harvard University who specializes in “labs-on-chips.” Dr. Whitesides and his laboratory have created micropatterned, paper-based analytical devices (μPADs), a paper microfluidics tool the size of a postage stamp (Fig. 1). The technology is currently being licensed for development to Dr. Whitesides' nonprofit company, Diagnostics for All. Clinical Chemistry chatted with Dr. Whitesides about his tool, as well as with Dr. Peter Wilding, a professor emeritus of laboratory and pathology at the University of Pennsylvania (who published one of the first reports on microfluidics in this journal). Fig. 1. A low-cost, micropatterned, paper-based device the size of a postage stamp was designed to use blood from a fingerstick to measure 3 markers of liver function. The device enables quantitative analysis of alkaline phosphatase (ALP), aspartate aminotransferase (AST) and total protein markers within 35 min. Reproduced with permission from Vella et al. (1). The paper microchip is a first-of-its-kind vertical-flow diagnostic tool composed of paper, wax, and a filter. Whitesides began thinking about a new technology for the developing world when he was working for the …