The patch clamp technique is a laboratory technique in electrophysiology that allows the study of single or multiple ion channels in cells. The technique can be applied to a wide variety of cells, but is especially useful in the study of excitable cells such as neurons, cardiomyocytes, muscle fibers, and pancreatic beta cells. It can also be applied to the study of bacterial ion channels in specially prepared giant spheroplasts.The patch clamp technique is a refinement of the voltage clamp.