Exposure to toxic metals like cadmium has been associated with adverse pregnancy outcomes such as miscarriage, preterm birth and low birth weight. Because these effects are difficult and ethically challenging to study directly in pregnant women, how such exposures affect pregnancy has remained poorly understood.

The placenta-on-a-chip model developed by Dan Huh, J. Peter Skirkanich professor in bioengineering, and colleagues at Penn Engineering offers a way to investigate these questions using living human cells. In a study published in Nature Biomedical Engineering, the team led by Huh, together with collaborators at Princeton, Sogang University in Seoul, Korea, and Rutgers University, used the bioengineered model to examine how cadmium, a toxic metal found in food, drinking water and tobacco smoke, affects the placenta's ability to support a developing fetus.

The group's experiments revealed that cadmium can impair the placenta even at relatively low exposure levels that do not kill cells. The researchers also identified a protein that helps protect placental tissue, along with metabolic changes that could provide clues to exposure-related damage.

Recreating the maternal–fetal interface
In the placenta, maternal and fetal blood circulate in separate compartments and exchange nutrients and other substances across a thin layer of tissue. Huh and his collaborators developed a microfluidic device that recreates key features of this maternal–fetal interface.

The device is built with human placental cells isolated from donated placentas. On one side, a layer of these cells is exposed to flowing fluid that simulates maternal blood. On the other, a three-dimensional tissue structure contains a network of fetal blood vessels embedded in a hydrogel scaffold.

The model also incorporates oxygen conditions that more closely reflect those inside the placenta than conventional cell culture systems. Researchers can introduce additional cell types, including placental immune cells, to investigate more complex biological responses.

Huh's earlier placenta-on-a-chip research focused on how drugs cross the placental barrier.

"Our new work expands the original capabilities of the technology and allows us to emulate the human maternal–fetal interface with greater fidelity and study the effect of environmental toxins under more realistic conditions," says Huh. "We can now ask not only whether cadmium crosses the barrier but also how it affects the placenta's ability to perform its key physiological functions." ...

No other traveler has ever journeyed so far from home.

Voyager 1 is about to become the first human-made object to reach a distance of one light-day from Earth, or about 16 billion miles. ½

Like most cats, Cooper used to love climbing into cardboard boxes. But one day, a box full of foam packing peanuts caught this tabby by surprise. Her owner, Sean McGrath, soon heard a commotion coming from the box and pulled her out. Thanks to static electricity, foam pellets now clung to her fur from head to tail.

Cooper seemed stunned. “She just stood there, frozen,” says McGrath, 44, of St. John, Canada. He snapped a photo before brushing her off. That picture, taken 20 years ago, eventually found its way to Wikipedia. Cooper unwittingly came to embody static electricity. She has appeared in textbooks, college lectures and more — all to help explain this sticky science.

Static electricity is common in everyday life. It’s why rubbing a balloon on your head makes your hair cling to it. It’s why clothing fresh from the dryer can stick to your legs. It’s also behind the painful shock you sometimes get when you touch a doorknob.

But the science of static electricity is surprisingly mysterious.

We know it’s caused by an electric charge moving between objects when they touch. But how — exactly — does that happen? In most situations, “we really have no clue,” says Galien Grosjean. A physicist, he works at the Autonomous University of Barcelona in Spain. He’s one of a small, quirky group of scientists who are obsessed with static electricity. The crew includes physicists, engineers, chemists and materials scientists.

Each researcher in this group holds a piece of the static-electricity puzzle. But they’re finally putting some of the pieces together to make progress...