Science is moving so fast it may soon be able to replace human body parts by simply printing them. Eventually that process will even mean printing directly into the body. For now a big step has been made with 3D printed body parts.

The breakthrough has involved scientists from Wake Forest Baptist Medical Centre printing body parts that actually function normally when implanted in living creatures.

We've already seen a 3D printed liver but the issue here was that without blood vessels to feed the cells it died. This new technique involves creating a sponge like structure, which can grow.

The machine that creates these wonders is called The Integrate Tissue and Organ Printing System, or Itop. This combines bio-degradable plastic for structure and water-based gel to hold cells.

These have already been implanted in animals where the plastic was broken down and replaced by natural proteins made by the cells. Blood vessel and nerves then grew into the implants.

On a human scale this could mean replacing a broken part of a jaw, say, with the exact shape needed.

In the future these printers may be able to print right into the human body, using the same material as the patient so rejection isn't an issue. Lost an arm? Just pop to your local limb dispenser and have a new one grown on. It's a long way off but we're going in that direction, and fast.

READ: 3D printed liver is here and it can survive for up to 40 days