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[30] Insertion of ion channels into planar lipid bilayers by vesicle fusion

1992; Academic Press; Linguagem: Inglês

10.1016/0076-6879(92)07032-j

1557-7988

Pedro Labarca, Ramón Latorre,

Nanopore and Nanochannel Transport Studies

This chapter describes the experimental procedures used to insert ion channels derived from cell membranes into planar lipid bilayers using fusion approaches. Planar lipid bilayers amenable to ion channel insertion can be produced, either by the painting technique or from two lipid monolayers spread at the air–water interface. The painted bilayers also contain solvent; the presence of solvent means that painted bilayers possess electrical capacitances that are notoriously smaller than those of cell membranes. Purified ion channels reconstituted in planar bilayers allow for detailed studies on the ion selectivity, voltage dependence chemical modulation, and pharmacological properties associated with a well-defined molecular structure. Most channels are perfectly cation or perfectly anion selective. However, most channels found in cell membranes are cation selective. A common artifact is the development of conductance increases that result from massive fusion of lipid vesicles to the planar bilayer.