Monitoring proliferative activities of hormone-like odorants in human breast cancer cells by gene transcription profiling and electrical impedance spectroscopy.

The human estrogen receptor alpha (ERα) mediates the proliferative action of hormones in breast cancer cells by regulating the expression of target genes to control cellular functions. Current methodologies do not permit a real-time assessment of these processes in living cells. We overcome this limitation using electrical cell-substrate impedance sensing for measuring ERα-regulated signaling processes indicative of the onset of cell proliferation to target them for compound screenings.

A synthetic membrane protein in tethered lipid bilayers for immunosensing in whole blood.

Tethered lipid bilayers, containing a transmembrane synthetic ligand-gated ion channel (SLIC), have been formed on gold surfaces. The SLIC was designed as a highly selective receptor and reporter protein to detect antibodies in whole blood, which are of importance in malaria diagnosis. The specific binding of the antibody to the sensor surface was monitored on-line with label-free surface-sensitive techniques either optically by surface plasmon resonance in whole blood or electrically by measuring the channel activity of SLIC in blood serum.

Probing the function of ionotropic and G protein-coupled receptors in surface-confined membranes.

This article reports on recent electrical and optical techniques for investigating cellular signaling reactions in artificial and native membranes immobilized on solid supports. The first part describes the formation of planar artificial lipid bilayers on gold electrodes, which reveal giga-ohm electrical resistance and the insertion and characterization of ionotropic receptors therein. These membranes are suited to record a few or even single ion channels by impedance spectroscopy.

Stable self-assembly of a protein engineering scaffold on gold surfaces.

The outer membrane protein OmpF from Escherichia coli is a member of a large family of beta-barrel membrane proteins. Some, like OmpF, are pore-forming proteins whilse others are active transporters or enzymes. We have previously shown that the receptor-binding domain (R-domain) of the toxin colicin N binds with high affinity to OmpF reconstituted into tethered lipid bilayers on gold electrodes.