Many important discoveries in cell biology have been made by introducing specific compounds into a certain cell and observing the effect. Several methods have been used for the introduction of the compounds. For example, permeabilizing the cell by electroporation (an electric shock that has been demonstrated to poke holes in the plasma membrane), the use of biologic molecules (such as streptolysin 0) to create channels in the plasma membrane, or detergents to dissolve hoies in the plasma membrane. Several laboratories have shown these methods to be effective, but one questions the physiologic state of a holey cell. Liposomes or similar vehicles can be packed with compounds and fused with the cells of interest, but this method of introduction has drawbacks as well.