An artificial lipid bilayer formed on a PEG-coated glass for simultaneous electrical and optical measurement of single ion-channels

The purpose of this study is to develop an apparatus for simultaneous measurement of electrical and spectroscopic parameters of single ion-channels. We have combined the single channel recording apparatus with an artificial lipid bilayer and a fluorescence microscope designed to detect single fluorescent molecules. The artificial membranes were formed on a PEG (polyethylene glycol)-coated glass and observed with an objective-type total internal reflection fluorescence (TIRF) microscope. The lateral motion of a single lipid molecule (β-BODIPY 530/550 HPC) was recorded. The lateral diffusion constant of the lipid molecule was calculated from the trajectories of single molecules as D = 8.0 ± 4.0 × 10^-8 cm²/s. Ionic channels were incorporated into the membrane and single-channel current fluctuations were recorded. These data show the possibility of the present technique for simultaneous measurement of electrical and spectroscopic parameters of single-channel activities