Scientists Say: Hydrogel

Hydrogels are polymer materials that can absorb lots of water

a glass bowl is filled to the brim with shiny wet orbs of all different colors

These colorful hydrogel toys, called Orbeez, may look yummy — but do not eat! If swallowed, these hydrogel beads can absorb water inside the body and create dangerous blockages in the gut.

Yulia Naumenko/Getty Images

Hydrogel (noun, “HY-droh-jel”)

Hydrogels are polymer-based materials that can hold a lot of water. Inside a hydrogel, chainlike polymer molecules form a mesh. Those polymers easily latch onto molecules of water (H2O). But the polymers are also tightly tangled or bonded together. This keeps them from coming apart. As a result, a hydrogel can hold its shape even after soaking up lots of water. Some hydrogels can absorb hundreds of times their own weight in H2O. 

Some hydrogels are made of natural polymers. Others are made with synthetic polymers. Jell-O, for instance, is a hydrogel made with gelatin. That’s a natural polymer made from collagen, found in animal tissue. Synthetic hydrogels have many uses. They are especially good for making medical tools or other objects that must safely touch living tissue. Why? Because hydrogels, like living tissue, are mostly water. Hydrogels are found in contact lenses. They are also used to make medical implants and bandages. Hydrogels can even be used to grow new human tissue in the lab.

In a sentence

Hydrogels could be used to soak up water from seemingly dry air.

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Maria Temming is the Assistant Managing Editor at Science News Explores. She has bachelor's degrees in physics and English, and a master's in science writing.

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