Methods for assembling biological molecules within lipid environments onto electrodes.

by Ha, Joomi; Henry, Charles Sherman; Fritsch, Ingrid


An ion channel polypeptide, Gramicidin A (gA), was assembled into org. films on electrodes to create and study possible materials for electrochem. sensing. One assembly method involves self-assembled "monolayers" (SAMs) from hexadecanethiol (C16SH) + gA mixts., followed by different solvent rinses. Ethanol rinses yield monolayers, but appear to remove gA. Water rinses form multiple layers of C16SH and gA. A second assembly method reproducibly forms bilayers by disruption of gA-contg. vesicles of dimyristoyl phosphatidylcholine (DMPC) onto ethanol-rinsed SAMs of C16SH + gA, followed by the water rinse. Ellipsometry verified the no. of layers of mols. in the films on the surfaces. Permeation of Fe(CN)63- is essentially negligible at all films. Electrochem. response to K+ and Mg2+ at bilayers and to Ag+ and Pb2+ at water-rinsed "SAMs" is consistent with the selectivity of the channel former of gA. The mere presence of gA might also cause this selectivity. Exact conformation of gA in these films has not yet been detd. [on SciFinder(R)]

Proceedings - Electrochemical Society