Breakthroughs with bar codes

Abstract

Forty trillion is the kind of number that gives one pause. Consider it written out with its 13 zeros: 40,000,000,000,000. Assembling and maintaining a collection of 40 trillion of anything seems like a mind-bogglingly massive task. But in February the Danish biopharmaceutical company Nuevolution announced that it had created a library of 40 trillion unique molecules—quite possibly the largest collection of synthetic compounds in the world. You might think it would require every building in Copenhagen to store batches of 40 trillion different compounds. Not so, says Alex Haahr Gouliaev, Nuevolution’s chief executive officer. “All of that fits into an Eppendorf tube and is handled by one person for screening,” he says. The substance that makes it possible to maintain this multitudinous mixture of molecules is the same substance that contains the code of life—DNA. Nuevolution covalently attaches a short, unique strand of DNA to each of its 40 trillion