The response of the polymer to pH or salt level makes the hydrogel “smart”. An application of this property is drug delivery. The hydrogel is called a carrier when loaded with medicine. As the swelling of the hydrogel increases, the chains of the network move further apart. As the chains move away from each other, the drug can diffuse more quickly through the hydrogel to the skin or other target area.
Researchers, such as Yun jung Heo, are working to develop a glucose responsive hydrogel for continuous glucose monitoring. The glucose sensor uses fluorescent hydrogel fibers. The sensor is implanted and the signal is accessed by wireless transmission.