Connecting 3-D-printed tissue to working blood vessels in the body may be the most significant step yet toward the creation of functional artificial organs for humans. It means that artificial organs that could survive long term in the body are technologically feasible. The researchers told the Gulf News that their next step is to print more complex organs.

“They were able to get large constructs that were viable long enough to be implanted, which is not trivial at all,” Gordana Vunjak-Novakovic, a biomedical engineer at Columbia University, told The Verge. “This is an important study that shows, convincingly and elegantly, that custom-designed tissues can be produced in lab.”

This month, after a Russian company successfully transplanted a working thyroid gland onto a mouse, the company’s CEO remarked that fully-printed organs may be as few as 15 years away.