patch clamp assay inside-out patch clamp assay A patch-clamp assay where a patch of the membrane is attached to the patch pipette, detached from the rest of the cell, and the cytosolic surface of the membrane is exposed to the external media, or bath. This provides the experimenter has access to the intracellular surface of the membrane via the bath and can manipulate the environment at the intracellular surface of single ion channels. For example, channels that are activated by intracellular ligands can then be studied through a range of ligand concentrations.