The Tungara Frog's bubble has won an award. In 2010, a team of researchers developed a foam—a model based on nature—that absorbs carbon dioxide from the air and produces sugar from it that can be converted into biofuel. For this, the researchers won the Earth Award. Now the foam of the Tongara frog can provide another advancement, this time in medicine.

Tongara frogs usually lay eggs during the mating season and wrap them with foam to form a foam bed, so to speak. This protects the offspring from drying out and from predators for 10 days, until the amphibian is large enough.

It is on these foam bags, except when Paul Hoskisson, a molecular microbiologist at Glasgow Strathclyde University, wanders in the jungles of Trinidad in the Caribbean. He wrote on his website that even when he was a little boy, he always took home buckets full of fish, snakes and frogs. Now as a researcher, he is continuing his childhood dreams. However, this time, he was interested in the peculiar bubble of the Tongara Frog. With the permission of the on-site forest ranger, he collected the nest.

The foam of Tongara frog has very special characteristics.

(Photo: Wikimedia Commons / Brian Gratwicke / cc by-sa 2.0)

Because the frog bubble is unusually stable. On the other hand, artificial foam and other natural foams usually decompose so fast that when you think of foam on beer or latte macchiato, you can observe them. But bathing and shaving foam is only a short-lived pleasure. In contrast, the frog's foam can withstand ten days of showers and storms. Hoskisson wanted to know exactly the reason and simulate the amphibian foam in the best case.

Therefore, as he described in the "Royal Society Open Science" magazine, he analyzed foam samples from the Caribbean Sea according to all the rules of microscopy and spectroscopy. The white matter is mainly composed of six kinds of proteins. These parts are arranged like clams, with the water-loving side of the molecule facing inward and the waterproof side facing outward. In Hoskisson's laboratory, the foam can easily withstand a force equivalent to a wind speed of 45 kilometers per hour. On the other hand, the egg white will collapse in the middle.

Hoskisson recognized the medical potential with such remarkable characteristics: the pores of the foam bubbles are suitable as pharmaceutical containers. Medical foam used for bandages has been particularly important for the care of wounds and scars. They slowly release drugs, such as antibiotics, and protect the injured area of ​​the skin from infection. For poorly healed wounds, such as burn patients' wounds, the foam can also contain painkillers and anti-inflammatory drugs.

But nowadays, wound dressings usually have to be changed every few hours. This disrupts the healing process because the newly formed skin is again subjected to mechanical pressure. In addition, bacteria can penetrate at the moment of exchange. According to the researchers, if the drug is administered through the frog foam within a few days, the interval between dressing changes can be extended.

Hoskisson hopes that because the foam in nature can protect the reproductive cells of amphibians, it should be well tolerated. For testing, he applied foam to human skin cells in the laboratory. In fact, cells divide normally and are not affected. The team of researchers then filled the antibiotic rifampicin into foam bubbles up to 3 mm in size. He was able to prove that the active ingredient was slowly released from the frog foam within 7 days.

In order to get closer to the super stable frog foam, Hoskisson now hopes to include all six proteins in the foam produced by the microorganisms. However, research is still needed before finding a fully developed bandage with foam wound protection à la Tungara frog.