Nanotube Membrane Sensors: Resistive Sensing and Ion Channel Mimetics

Abstract

Nanotubule membranes are utilized for sensing applications and ion channel mimetics. The nanotubule membranes are composed of either gold or alumina. The gold nanotubule membranes are prepared via electroless deposition of Au on to the pore walls of a polycarbonate membrane, ie, the pores act as templates for the nanotubes. These membranes are a new class of molecular sieves and can be used to separate small molecules on the basis of molecular size. In addition, the use of these membranes in new approaches to electrochemical sensing is discussed. In this case, a current is forced through the nanotubes, and analyte molecules present in a contacting solution phase modulate the value of this transmembrane current. We further discuss synthetic micropore and nanotube membranes that mimic the function of a ligand-gated ion channel, ie, these membranes can be switched from an ‘off’ state (no or low ion current through the membrane) to an ‘on’ state (higher ion current) in response to the presence of a chemical stimulus, eg, drug or surfactant. Ion channel mimics are based on both modified Au nanotube and microporous alumina membranes. First published online: July 12, 2002.