Schematic of the sensor fabrication and operation. (A) MSEs were fabricated on pre-stressed polystyrene (clear rectangle), which was masked during gold deposition using an adhesive vinyl stencil (red). After sputtering a thin gold layer (yellow), the stencil was removed to reveal the patterned electrode. Thermal shrinking of the substrate resulted in structuring of the Au film. (B) Each MSE was masked to deposit lipid solution only on the sensing pad. The solvent was evaporated, forming a thin lipid film that was annealed under constant temperature and humidity conditions. Prior to sensing, a mask was applied onto the MSE pad to ensure a reproducible membrane sensing surface. (C) Schematic of the 3-electrode electrochemical sensing set up. The DMPC-coated MSE was used as the working electrode (WE), with a Pt wire as the auxiliary electrode (AE), and a standard Ag/AgCl reference electrode (RE). (D) 3D optical reconstruction of 20-nm-thick flat and 20–400 nm-thick wrinkled Au films. All optical images taken at the same magnification.