Research labs use many types of 3D printers to construct everything from fossil replicas to tissues of beating heart cells. Arthur Olson’s team at the Scripps Research Institute in La Jolla, California, produces models of molecules; some are shown here partway through the printing process.
Chemists and molecular biologists have long used models to get a feel for molecular structures and make sense of X-ray and crystallography data. Just look at James Watson and Francis Crick, who in 1953 made their seminal discovery of DNA's structure with the help of a rickety construction of balls and sticks.
These days, 3D printing is being used to mock up far more complex systems, says Arthur Olson, who founded the molecular graphics lab at the Scripps Research Institute in La Jolla, California, 30 years ago. These include molecular environments made up of thousands of interacting proteins, which would be onerous-to-impossible to make any other way. With 3D printers, Olson says, “anybody can make a custom model”. But not everybody does: many researchers lack easy access to a printer, aren't aware of the option or can't afford the printouts (which can cost $100 or more).
Yet Olson says that these models can bring important insights. When he printed out one protein for a colleague, they found a curvy 'tunnel' of empty space running right through it. The conduit couldn't be seen clearly on the computer screen, but a puff of air blown into one side of the model emerged from the other. Determining the length of such tunnels can help researchers to work out whether, and how, those channels transport molecules. Doing that on the computer would have required some new code; with a model, a bit of string did the trick.
3D printer 'inks' aren't limited to plastic. Biologists have been experimenting with printing human cells — either individually or in multi-cell blobs — that fuse together naturally. These techniques have successfully produced blood vessels and beating heart tissue. The ultimate dream of printing out working organs is still a long way off — if it proves possible at all. But in the short term, researchers see potential for printing out 3D cell structures far more life-like than the typical flat ones that grow in a Petri dish.