Stimulus-responsive gels: Promising materials for the construction of micro actuators and sensors

Polymer gels are very promising for the realization of devices which function autonomously in response to physical or chemical stimuli. Because they can also be used as basic building blocks in constructing very inexpensive devices, the authors have used polymer gels to construct microactuators for use in measuring glucose concentrations. In a micropump, an external solution is withdrawn by changing the temperature. The sampling time is also adjusted by using a pH change caused by an enzymatic reaction. The same mechanism can be applied to the construction of a spontaneously functioning biosensor, through which glucose concentrations can be measured from changes in length of the liquid column.