High Yield, Reproducible and Quasi‐Automated Bilayer Formation in a Microfluidic Format

Abstract A microfluidic platform is reported for various experimentation schemes on cell membrane models and membrane proteins using a combination of electrical and optical measurements, including confocal microscopy. Bilayer lipid membranes (BLMs) are prepared in the device upon spontaneous and instantaneous thinning of the lipid solution in a 100‐μm dry‐etched aperture in a 12.5‐μm thick Teflon foil. Using this quasi‐automated approach, a remarkable 100% membrane formation yield is reached (including reflushing in 4% of the cases), and BLMs are stable for up to 36 h. Furthermore, the potential of this platform is demonstrated for (i) the in‐depth characterization of BLMs comprising both synthetic and natural lipids (1,2‐diphytanoyl‐ sn ‐glycero‐3‐phosphocholine (DPhPC) and L ‐α‐phosphatidylcholine ( L ‐α‐PC)/cholesterol, respectively) in terms of seal resistance, capacitance, surface area, specific capacitance, and membrane hydrophobic thickness; (ii) confocal microscopy imaging of phase separation in sphingomyelin/L‐α‐PC/cholesterol ternary membranes; (iii) electrical measurements of individual nanopores (α‐hemolysin, gramicidin); and (iv) indirect assessment of the alteration of membrane properties upon exposure to chemical stimuli using the natural nanopore gramicidin as a sensor.