By Michelle Durham

PHILADELPHIA (CBS) - Scientists at the University of Pennsylvania have teamed up with their counterparts all over the world, working to develop human organs from the stem cells of the patient.

Using a 3-D printer, and other tools, their goal is to eradicate the risk of rejection by building organs that won’t require the immunosuppressant drugs current patients have to take.

Professor of Innovation in the Department of Bioengineering at the University of Pennsylvania, Dr. Christopher Chen says he and his colleagues have been working hard on using stem cells to engineer tissues.

“One of the big limitations for being able to assemble the cells into larger structures such as hearts or livers [is that] once you form a tissue that is larger then a certain size all the cells in the center of that block will starve because they are not getting access to oxygen or blood,” explains Dr. Chen.

Postdoctoral fellow Jordan Miller who works with Chen saw an exhibit featuring donated human organs filled with silicone so Miller wondered if he could create the pathways for the blood flow first and then build the organs around it.

Right now they can make pathways the size of a pinky, but Chen and Miller hope that in 10 years time the technology will be advanced enough to create an organ from these gels in their lab.

But it will be many more years before they can be transplanted into a patient.