Applications of biological pores in nanomedicine, sensing, and nanoelectronics.

Using novel synthetic lipids, a tethered bilayer membrane (tBLM) was formed onto a gold electrode such that a well-defined ionic reservoir exists between the gold surface and the bilayer membrane. Self-assembled monolayers of reservoir-forming lipids were first adsorbed onto the gold surface using gold−sulfur interactions, followed by the formation of the tBLM using the self-assembly properties of phosphatidylcholine-based lipids in aqueous solution. The properties of the tBLM were investigated by impedance spectroscopy. The capacitance of the tBLM indicated the formation of bilayer membranes of comparable thickness to solvent-free black (or bilayer) lipid membranes (BLM). The ionic sealing ability was comparable to those of classical BLMs. The function of the ionic reservoir was investigated using the potassium-specific ionophore valinomycin. Increasing the size of the reservoir by increasing the length of the hydrophilic region of the reservoir lipid or laterally spacing the reservoir lipid results in a...

Tethered Lipid Bilayer Membranes: Formation and Ionic Reservoir Characterization

Adsorption of a monolayer of dimyristoyl-L-α-phosphatidylcholine from dispersions of small unilamellar vesicles onto hydrophobic surfaces was investigated by means of a combined surface plasmon res...

Fusion of Small Unilamellar Lipid Vesicles to Alkanethiol and Thiolipid Self-Assembled Monolayers on Gold

Surface plasmon resonance spectroscopy as a tool for investigating the biochemical and biophysical properties of membrane protein systems. II: Applications to biological systems.

A novel β-cyclodextrin (β-CD) functionalized by a mercaptopropionic acid that was attached to a single 6-deoxyaminoglucose unit has been synthesized in the disulfide form. The flexible single-thiol spacer allows the formation of a monomolecular film by self-assembly onto gold, yielding a high packing density with a surface coverage of 99.6% and a capacitance of 9 μF/cm2, determined by impedance spectroscopy. MALDI-MS and XPS analysis clearly showed that the modified cyclodextrin is chemisorbed on the gold surface by Au−S bonds. Addition of 3-mercaptopropionic acid to the preformed β-CD monolayer considerably improved the intensity of the MALDI mass spectra signals. The incorporation of anilinonaphthalenesulfonates into the β-CD cavity was observable by impedance spectroscopy using the electroactive markers [Fe(CN)6]3-/[Fe(CN)6]4-.

Self-Assembled Monolayers of Monofunctionalized Cyclodextrins onto Gold: A Mass Spectrometric Characterization and Impedance Analysis of Host−Guest Interaction

Cary Miller

Papers

K+ sensitive bilayer supporting electrodes