Bring artificial gills to live under the sea

  There is such a beautiful myth: a kind fisherman rescued a golden fish on the beach that was about to die and put it back into the sea. In order to repay the fisherman, Xiaoyu gave him a sea avoiding pearl. From then on, the fisherman can freely travel between the Undersea Dragon Palace and the land.
  This story reflects people’s beautiful desire to conquer the sea. Today, through the hard work of scientists, this myth is becoming a reality.
The first “scuba”

  One day in June 1943, on the coast of Libya, several people opened a box and took out a strange shape from it. They called it “scuba”. The skinny man with a hooked nose is the world-famous inventor of scuba, Kustu, with his assistant standing next to him. They will use this scuba to conduct a diving test without water supply of oxygen and no safety signal rope connection. There are great risks in this unprecedented experiment.

  The so-called scuba is a knapsack-type oxygen cylinder diving device that has been widely used in diving activities today. It consists of a gas cylinder filled with high-pressure oxygen and helium mixed gas, an air supply regulator equipped with a special valve, and a hose and gas. Consists of a breathing mask connected to the bottle.
  Kustu puts a scuba weighing 30 kilograms on his back, puts on a swimming web, and bit the breathing mask on his mouth. Everything was ready, he took a firm step toward the sea, and gradually disappeared under the water.

  Time passed by, and the people on the shore were so nervous that they mentioned their throats… Finally, Kusitu and the silver-white oxygen cylinder were exposed to the sea, and people cheered for joy. He succeeded!
  Kustu’s invention opened a new chapter in the history of human diving. However, people are not satisfied with the limited diving time and underwater freedom provided by scuba. Why don’t fish drown in the water? Can you imitate fish gills and create an artificial gill that allows humans to directly absorb oxygen in the water?
Bird in the water

  In 1985, at the Tsukuba International Science and Technology Fair in Japan, there was an interesting exhibit-in a rectangular glass fish tank filled with clear water, there was a bird jumping happily!
  It turns out that the bird lives in a sealed glass “birdcage” in the water. The “birdcage” is connected by two tubes to a complex device that is also submerged in the tank. This complex device is an artificial gill that can obtain oxygen directly from the water and supply the birds to sustain life. This artificial gill was developed by Japanese scientists Nobunhisa Kawaguchi and Kuwanajiro spent ten years of hard work.
  Hidden in this artificial gill are more than 1,000 slender silicone rubber tubes 25 cm long and only 0.3 mm in diameter. These silicone rubber tubes have a “sieve”-like function-when water flows through the artificial gills, the tube wall can block the penetration of water molecules and “sieve” the oxygen molecules in the water into the inside of the thin tube. In this way, the numerous thin tubes provide enough oxygen to sustain life for the birds in the fish tank.
  Unfortunately, the ventilation efficiency of the currently used silicone rubber tubes is still too low. To obtain a large amount of oxygen from the water, the number of thin tubes must be greatly increased. It is estimated that to provide the amount of oxygen used by an adult, at least more than 20,000 such thin tubes are needed. The combination of so many thin tubes full of oxygen will make the artificial gills become a “life jacket” that prevents people from diving. In addition, silicone rubber has poor corrosion resistance to seawater, so long-term immersion in seawater will threaten the safety of divers. Therefore, this artificial gill made of silicone rubber tube cannot be put into use immediately.
  Can we find a more advanced and effective method?
The wonderful “hemoglobin sponge”

  In the early 1980s, American scientist Bownerbank successfully developed an artificial gill that can efficiently absorb oxygen from seawater. It is made of a special material called “hemoglobin sponge” based on the biochemical principle of fish gills absorbing oxygen in water.
  It turns out that in the blood of animals, there is a blood protein called “hemoglobin” that is specially used to exchange and transport oxygen molecules. Based on this scientific principle, Bowerbank used a special processing technique to fix hemoglobin purified from human blood on a sponge-like material made of silica and polyurethane to make a “hemoglobin sponge” . When this sponge is immersed in water, a large amount of hemoglobin firmly captures the oxygen molecules in the water. At this time, as long as a certain current is applied to the sponge, the oxygen molecules will break away from the “carrier” by themselves, become oxygen, and be continuously released.
  At present, scientists have made a “hemoglobin sponge” into an artificial gill for experiments. This artificial gill with a diameter of about 1 meter and a length of about 3 meters can provide 150 people with underwater oxygen, and the average “hemoglobin sponge” occupied by each person is less than 0.03 cubic meters. In recent years, Japanese scientists have also used “hemoglobin sponges” to make artificial gills, which people can wear on their heads and dive into the water for a week. It’s a pity that this artificial gill is large in size and inconvenient to use. But scientists predict that in the near future, there will be small and lightweight knapsack artificial gills. With the continuous improvement of technology, there will even be artificial gills in the form of masks or mouths in the future. At that time, people can live under the sea for a long time.