Researchers at the National Institutes of Health announced Thursday that they have developed a device that puts a "mini-placenta" on a chip to better understand the organ's role in pregnancy, highlighting new technology that's showing up in labs across the country and may reduce the amount of animal testing over time.

Studies like these are generally done on the micro level. Human cells are grown onto the chips, which look something like a computer flash drive and are designed to mimic the functions of full organs. The technology is said to be more accurate and less costly than studying human cells in dishes or similar cells in animals.

"I try not to hate on people doing animal experiments — we do that, too," said Roberto Romero, who has been studying placentas with the chip at the National Institute of Child Health and Human Development. "But we can do this [with the chip] before we go to the animal."

In Romero's work, the device is cheap to make (about $10 a piece), and it's easier to study than mice — not to mention, there are some big difference between the placentas in mice and the placentas in humans. The chip takes about a day to make, with about a week to grow the cells.

The NIH plans to use the technology to study the inner workings of the human placenta in ways never done before. The temporary organ found in pregnant mothers, described by Romero as "completely understudied,"  acts like a "crossing guard" for substances moving from a woman to her fetus, according to a study released Thursday in the Journal of Maternal-Fetal & Neonatal Medicine.

The researchers replicated the organ by putting maternal cells from a delivered placenta on one compartment in the device and fetal cells from an umbilical cord on another. They then tested how substances like glucose are transferred from the two compartments.

Generally, studying the placenta is time-consuming and dangerous because it's risky for the fetus. But now the team at NIH — including researchers from the University of Pennsylvania, Wayne State University/Detroit Medical Center, Seoul National University and Asan Medical Center in South Korea — can figure out how different materials move across that barrier.

Romero said that may lead to big discoveries for the health of children, such as how viruses and chemicals passing from mother to fetus can affect development.

"It allows us to ask many, many questions that are difficult to answer," he said.

But the technology doesn't stop there. Institutions across the country are following up on the concept, pioneered at the Wyss Institute at Harvard University. Wyss has managed to put together a mini-lung, kidney and intestine on a chip, while the University of California-Berkeley has made a similar device that has live, pumping heart cells.

UC Berkeley researchers are testing heart drugs on human cardiac muscle cells housed in an inch-long silicone device. The video shows cardiac muscle cells before and after exposure to isoproterenol, a drug used to treat certain heart ailments. (Anurag Mathur/University of California, Berkeley)

Emulate Inc., a biotech company in Boston, also announced Thursday that it will be using the technology to recreate thrombosis — better known as a blood clot — to see how drugs can affect blood flow and the interaction of platelets.

Don Ingber, director of the Wyss Institute, suggests that as the technology gains popularity, it will speed up the process for pharmaceutical companies to test new drugs for targeted populations.

"It's caught on because it's so visual and so meaningful," Ingber said. "You're seeing some interdisciplinary interaction between engineering and biology. It's very moving and very powerful."