It has four chambers, blood vessels and it beats — sort of.
In a first, scientists have 3D printed a heart using human tissue. Though the heart is much smaller than a human's (it's only the size of a rabbit's), and there's still a long way to go until it functions like a normal heart, the proof-of-concept experiment could eventually lead to personalized organs or tissues that could be used in the human body, according to a study published Monday (April 15) in the journal Advanced Science.