A rapid form of 3D printing that uses sound and light could one day produce copies of human organs made from a person’s own cells, allowing for a range of drug tests.
Traditional 3D printers build from a hard base, layer by layer. This is time consuming and risks damage to printed objects when they are removed from the printing bed. David Collins at the University of Melbourne and his colleagues have taken a different approach, which they call “dynamic interface printing”.
The new printer is essentially a pressurised hollow tube that is lowered into a bath of resin. Air pressure maintains an interface between the open end of the tube and the resin, which cures and hardens when exposed to light. By projecting slices of an object onto this interface one at a time, the printer can build up a 3D structure.
Speakers are used to vibrate the interface, creating waves that speed up the curing process. This means the printer is much faster than comparable resin 3D printers, laying down 0.7 millimetres of structure per second compared with a previous record of 0.14 millimetres of structure per second, says Collins.
So far, the researchers have printed objects up to 3 centimetres in diameter and 7 centimetres long, with a resolution of 15 micrometres. “That allows us to print structures on the scale of a single cell,” says Collins.
Because the printed object floats in the resin as it is created, Collins says the printer can also handle difficult constructions. “We can print really soft, really delicate structures using really soft materials, softer than anything currently being used,” he says. “The ability to print materials mimicking the stiffness of native tissues makes this printer a great approach for growing cells and functional tissues.”
Since the printing interface is permeable rather than solid, it could also be used for “multi-material” printing – in other words, says Collins, you could first print bone tissue, then tendons and then skin.
One of the first applications of the 3D printer the team envisages is to be able to take tissue samples from a patient and print functional, custom tissue models. This could one day mean that multiple functional 3D kidneys for a patient could be printed quickly and tested with an array of drugs to see which ones work best, says Collins.
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