Electro-optical BLM chips enabling dynamic imaging of ordered lipid domains

Abstract

Studies of lipid rafts, ordered microdomains of sphingolipids and cholesterol within cell membranes, are essential in probing the relationships between membrane organization and cellular function. While in vitro studies of lipid phase separation are commonly performed using spherical vesicles as model membranes, the utility of these models is limited by a number of factors. Here we present a microfluidic device that supports simultaneous electrical measurements and confocal imaging of on-chip bilayer lipid membranes (BLMs), enabling real-time multi-domain imaging of membrane organization. The chips further support closed microfluidic access to both sides of the membrane, allowing the membrane boundary conditions to be rapidly changed and providing a mechanism for dynamically adjusting membrane curvature through application of a transmembrane pressure gradient. Here we demonstrate the platform through the study of dynamic generation and dissolution of ordered lipid domains as membrane components are transported to and from the supporting annulus containing solvated lipids and cholesterol.

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

“…Although the combination of electrical and optical measurements provides insight into the membrane properties, this approach is limited to the “macro” scale as only the surface area of the bilayer can be measured using bright field microscopy. For a better understanding of processes occurring at the molecular level, as for instance lipid diffusion and organization in the membrane9, 43, 44 or single nanopore activity measurements,45 high resolution techniques such as confocal microscopy are required.…”

Characterizing the Lateral Friction of Nanoparticles on On‐Chip Integrated Black Lipid Membranes

“…Different approaches have been developed to form membranes over the created wells or apertures 26. Lipid bilayer self‐assembly through vesicle deposition is widely used for on‐chip BLM formation 24, 27–30. In addition, BLM formation by the contact of two lipid monolayers at the oil/water interface inside a flow chamber has been demonstrated 31, 32…”

Rotational chambers on fluidic channels for the repetitive formation of optically observable lipid-bilayer membranes

“…However, the method is hardly compatible with microscope observation of the bilayer, because the bilayer is formed in a vertical manner to a focal plane of a microscope. Although there were some methods for optical observable bilayer [8][9][10][11][12][13][14], it is impossible to simply reform the lipid bilayer with the methods. We recently reported a device that formed optically observable lipid bilayer based on the droplets contact method [15].…”