Scientists have grown a human ear built from a mould created by a 3D printer.

The team from Massachusetts General Hospital had a plastic surgeon help with the design of the ear model to ensure the shape and proportions were correct before printing it as a mould.

This was then cast in a special silicone compound and split along the outer contour, giving them two separate moulds.

These were lined with wire to keep their shape and filled with cow collagen, which gave them elasticity and strength, before the researchers took ear cartilage cells from sheep.

The cells were then grown inside rats until the team had enough cartilage to replace the cow collagen inside the ears, and they said the ears had enough definition in the curves and lines to be recognisable even after a layer of skin had been applied.

The scientists reported that the ears responded well to stress tests, keeping their shape.

The development shows the extent to which 3D printing can be used to create precise moulds for such uses, and perhaps foreshadows an increasing use of the technology in science.

At the start of July scientists at Princeton University sent cow cells mixed with a liquid gel through a printer, then tiny particles of silver, and printed out a ‘bionic ear’, with the silver forming a coiled antenna.

A startup called Modern Meadow is hoping to bioprint artificial raw meat and company Organovo Holdings has the ability to print a variety of human tissue and cell types.

The future could be rather spectacular, with the potential there to theoretically print real living tissue prosthetics and, one day perhaps, even working organs.