Growing organs in a lab is no longer science fiction. Universities have already proven that you can grow tissue or blood vessels with 3D printers. One company has now taken it a step further, however, by combining the two.

NewScientist reports that Organovo, a San Diego-based medical company, has created a fully functioning human liver via 3D printing. The only catch is that these livers are ridiculously tiny.

Organovo was able to create its tiny livers by using a 3D printer to layer cell after cell until fully functioning liver tissue was formed. It also used cells from blood vessels to ensure that the tissue was getting all of the nutrients that it needed.

For now, the tissue can only live for five days. During that time, however, researchers are able to put it through a number of tests. The hope is that this first batch of liver tissue can be used to reduce the amount of time needed to test new drugs as the 3D printed liver reacts to treatment just like a real liver would.

Of course, the ultimate goal is to create a full-sized human liver. Thousands of people die each year waiting for a transplant. With 3D printed organs, doctors would be able to create a liver from the patient’s own cells so as to ensure perfect compatibility.

Let’s just hope that the advent of 3D printed organs doesn’t throw us into a dystopian world reminiscent of Repo.