Gift-giving season is approaching, and with it comes a twinge of worry for parents of young children: The toys and gadgets that bring joy on holiday mornings often include small parts that can wind up in little ones’ mouths.
Researchers at the Massachusetts Institute of Technology, Brigham and Women’s Hospital, and Massachusetts General Hospital say they believe their latest invention can take the danger out of at least one of those parts — the button- and coin-cell batteries that power watches, musical greeting cards, and some playthings.
Smaller than a piece of candy, the batteries typically are not a choking hazard. And with chemicals securely encapsulated, the poisoning risk is low. Many times they pass through the body with no effect.
But lodged in a child’s esophagus or stomach, they can discharge an electrical current capable of burning a hole in the lining of internal organs. Resulting injuries can be serious or even fatal. Thirty-seven deaths have been reported since 1977 — 25 since 2008.
The local research team developed a battery coating that has been shown in lab tests to deactivate an ingested battery without compromising its performance in electronic devices.
If taken to market, the coating, which resembles a thin patch, would be a significant upgrade over current safety techniques.
Despite child-resistant packaging, warning labels, and public awareness campaigns by manufacturers, emergency room visits due to battery ingestion are on the rise — from about 1,500 in 2000 to 4,800 in 2010, according to estimates by the National Electronic Injury Surveillance System.
“Efforts to prevent swallowing are good, but we all know the gold standard is a safer battery,” said Toby Litovitz, medical director of the National Capital Poison Center, who has published research on battery injuries. “If this new technology works, it would be a game changer.”
Burns are possible because human tissue can mimic the metal contact strips found in the battery cases of electronic devices, drawing out power.
Litovitz, in her research, found permanent damage can occur in just two hours and saw cases where even “dead” batteries had enough residual charge to cause harm.
A harrowing episode four years ago prompted a Peoria, Ariz., couple to start a foundation devoted to educating parents about the hazards of battery ingestion. Their 1-year-old son, Emmett, swallowed a battery he had dislodged from a DVD remote control and needed surgery to repair his badly burned esophagus.
Now 5, the boy still consumes most of his food through a feeding tube that he probably will need for the rest of his life.
“Everybody has button batteries in their house, and so few people know the dangers,” said Karla Rauch, the boy’s mother and president of the Emmett’s Fight Foundation. “I’m just really excited about this coating. I don’t know if it’s foolproof yet, but the fact that people are working on it makes us super happy.”
To prevent injuries to children like Emmett, researchers tested a rubberlike material called quantum tunneling composite, which already is used in computer touch screens. It contains metal particles that are spread too far apart to conduct electricity — until they are squeezed closer together.
On a battery, the composite acts as a layer of insulation between the electrode and a child’s tongue, throat, or gastrointestinal tract, blocking the harmful zap. In a hearing aid, remote control, or other device, however, pressures applied in the battery case are strong enough to push the metal particles together and create a closed circuit for the juice to flow.
“It’s like a switch that converts from an insulator to a conductor, based on whether it’s in the device or not,” said Jeffrey Karp, associate professor at Brigham and Women’s and coauthor of a paper about the battery coating.
Karp’s collaborators include Giovanni Traverso, a gastroenterologist at MGH; Robert Langer, associate faculty member at MIT’s Institute for Medical Engineering and Science; and Bryan Laulicht, a former postdoctoral research fellow at the institute.
Karp said another year or two of testing is probably needed before coated batteries could start showing up in consumer electronics. They have been tested in pigs but not in humans and would need to prove their reliability in a wide range of electronics before manufacturers would trust them.
But battery makers said they welcomed a possible solution to a problem that keeps growing as more electronics enter circulation. In recent years, companies like Energizer and Duracell have started packaging batteries individually to make them harder for children to access and have experimented with coatings that taste bad, hoping kids will spit them out.
“Safety is a top priority, but the issue has been performance,” said Win Sakdinan, a Duracell spokesman. “So we’re always looking at new innovations.”