Simple bandages are easy to use. They cover and protect wounds, giving them time to heal. Now scientists say they are developing new kinds of bandages. They have begun adding small sensors to bandages. making them more sensitive. This is the technology used in popular wearable devices, such as smart watches and fitness trackers.

Scientists are also making new materials, called hydrogels. Hydrogels are similar to human skin. Researchers at the Massachusetts Institute of Technology have found a way to combine these two technologies.

They created a stretchy material that is similar to human tissue. The new product has wires that lie in a "z" shaped design. The wires connect to the electronic sensors and stretch easily without breaking contact to the sensors.

Xuanhe Zhao teaches mechanical engineering at MIT. He says the resulting product becomes a type of "smart-wound dressing." It can react to changes in the skin around it.

For example, Zhao says, if there is a sudden increase in temperature, a command will be sent. That command can control the delivery of a drug to a special location. LED lights in the bandage could warn patients and doctors about changes in the wound. Medication can quickly spread across the bandage, through tiny passages.

Researchers say the new material can be used both on the skin, and inside the body. But it will be some time before these "smart bandages" reach the hospital or drug stores.