Scientists have long known that stem cells naturally cling to feeder cells as they grow in petri dishes. Researchers have thought that this attachment occurs because feeder cells serve as a support system, providing stems cells with essential nutrients.

But a new study that successfully grew stem cells with dead, or fixed, feeder cells suggests otherwise. The discovery (“Chemically fixed autologous feeder cell-derived niche for human induced pluripotent stem cell culture”), described in the Journal of Materials Chemistry B, challenges the theory that feeder cells provide nutrients to growing stem cells. It also means that the relationship between the two cells is superficial, according to Binata Joddar, Ph.D., a biomedical engineer at The University of Texas at El Paso (UTEP).

“We've proved an important phenomenon,” said Dr. Joddar, who runs UTEP's inspired materials and stem-cell based tissue engineering lab. “And it suggests that these feeder cells, which are difficult to grow, may not be important at all for stem cell growth.”

In the study, feeder cells were chemically fixed before living stem cells were placed in the same dish. Like organs that are preserved with formaldehyde, this kept the feeder cells' physical appearance the same, but essentially killed them.

Even though the feeder cells were dead, the stem cells still latched on and grew successfully.

The discovery offers a simpler and more cost-effective way to grow stem cells, which has proved difficult over the years, according to Dr. Joddar.

“Because feeder cells don't need to stay alive in the process, we can store them at room temperature and spend less time cultivating them,” said Dr. Joddar, who believes the finding suggests that stem cells may only like the “topology” of feeder cells.

“hiPS cells [human induced pluripotent stem cells] cultured on chemically fixed feeders formed teratomas in vivo, characterized by all three germ layers,” wrote the investigators. “The chemically fixed autologous feeders may be used as a substitute for large scale culture of hiPS cells as a convenient in-house and a cost-effective method.”

“This makes me think that we use a nanomanufacturing approach to grow stem cells,” continued Dr. Joddard “We could mimic feeder cells' nanotopology with 3D printing techniques and skip using feeder cells altogether in the future.”