3D printing molecules to order.

Popular Mechanics takes the 3D printer to the next level – synthesizing not new shapes, but new chemicals from scratch:

In a new study published in the journal Science today, [University of Illinois chemist Martin] Burke has announced the specs of a chemistry’s own version of the 3D printer—a machine that can systematically synthesize thousands of different molecules (including the ratanhine molecular family) from a handful of starting chemicals. Such a machine could not only make ratanhine step-by-step, but also could custom-create a dozen other closely-related chemicals—some never even synthesized before by humans. That could allow scientists to test the medicinal properties of a whole molecular family.

Whether you’re trying to form a ring of carbon atoms or strip away hydrogen atoms, each step requires a dose of starting chemicals, which Burke separates into distinct building blocks. Think of them as simple groups of chemical compounds like O2 or CO2 that snap together.

To perform each step, the machine connects a building block and then induces a chemical reaction and washes away the reaction’s byproducts—slowly building each molecule from the ground up. The building blocks are snapped together like LEGOs, allowing the chemicals to mix and a reaction to take place.