Mechanically Stable Lipid Bilayers in Teflon-Coated Silicon Chips for Single-Channel Recordings

We demonstrate the microfabrication of a low-noise silicon (Si) chip as a platform for suspending mechanically stable bilayer lipid membranes (BLMs). Microapertures with smoothly tapered edges were formed by isotropic etching in a silicon nitride layer deposited on a Si substrate. The surface of the Si chip was coated with insulator layers of Teflon and SiO2. The insulator coating worked to reduce the total capacitance, leading to noise reduction (1-2 pA in peak-to-peak after low-pass filtering at 1 kHz) and elimination of current transients (< 0.5 ms). Since the tapered edges were necessary to maintain mechanically stable BLMs, the entire chip except for the aperture was coated with the insulators. Owing to this process, the BLMs formed in the Si chips still showed high mechanical stability after coating with the insulator layers. The membranes withstood high applied voltage (±1 V) and mechanical shocks during solution exchanges. The mechanically stable BLMs having electric properties suitable for recording activities of biological channels will open up a variety of applications including high-throughput analysis of ion-channel proteins.