Because the demand for donors' organs and tissues is so high, researchers have spent years engineering synthetic tissues that could be transplanted into humans. But that's not very easy to do—many of the gel-like tissues have been too mushy to be moved into a living organism, and without the intricate pathways in the tissue through which oxygen and other nutrients can travel, the living cells inside don't survive long.

Now a team of researchers from Wake Forest University has created a 3D bioprinting tool that creates large synthetic bone, cartilage, and muscle tissue that is viable for weeks or months at a time when implanted in animals. With a bit more work, the researchers believe these 3D printed tissues could be transplanted into humans, according to a study published today in Nature Biotechology.