In 1991, physicist Erwin Neher and cell physiologist Bert Sakmann of the Max Planck Institute for Biophysical Chemistry in Göttingen, Germany were awarded the Nobel Prize for their 1974 development of the Patch Clamp, the first device to measure the flow of electrical current through single-ion channel proteins embedded in membranes, confirming the existence of single ion channels. 
     In a Patch Clamp apparatus a tiny glass pipette filled with salt solution is placed against a plasma membrane of a living cell. A small amount of suction is applied, forming a tight seal between the 0.5m diameter pipette tip and an ion channel. All ions that pass through the channel then flow into the pipette, and the incredibly small electrical currents - on the scale of a picoampere, or 10^{-12 Amp}, lasting only 10-100 msec can be recorded*.