Stable Free-Standing Lipid Bilayer Membranes in Norland Optical Adhesive 81 Microchannels

Abstract

ABSTRACT. We report a simple, cost-effective and reproducible method to form free-standing lipid bilayer membranes in microdevices made with Norland Optical Adhesive (NOA81).Surface treatment with either alkylsilane or fluoroalkylsilane enables the self-assembly of stable DPhPC and DOPC/DPPC membranes. Capacitance measurements are used to characterize the lipid bilayer and to follow its formation in real-time. With current recordings, we detect the insertion of single α-Hemolysin pores into the bilayer membrane, demonstrating the possibility of using this device for single-channel electrophysiology sensing applications. Optical transparency of the device and vertical position of the lipid bilayer with respect to the microscope focal plane, allows easy integration with other single-molecule techniques, such as optical tweezers. Therefore, this method to form long-lived lipid bilayers finds a wide range of applications, from sensing measurements to biophysical studies of lipid bilayers and associated proteins.

Hydrodynamic shear dissipation and transmission in lipid bilayers

“…Freestanding lipid bilayers are formed in microfluidic devices following a previously described protocol ( 38 , 39 ) ( Materials and Methods ). The microfluidic devices consist of two parallel rectangular microchannels (100- m high and 500- m wide) with several apertures between the two channels, where lipid bilayers are formed ( Fig.…”

“…Microfluidic devices were fabricated following the technique from Marin and coworkers ( 38 , 39 ). Specifically, we prepared devices with two parallel rectangular microchannels (100- m high and 500- m wide) with several 85- m-wide apertures where the two channels meet and lipid bilayers can form ( Fig.…”

“…Here, we perform active, noncontact, two-point microrheology to characterize the viscous and frictional properties of the bilayer. Our approach uses a planar freestanding lipid bilayer ( 38 , 39 ). The planar geometry of the freestanding membranes allows us to decouple in- and out-of-plane deformations, which facilitates the interpretation of the measurements using hydrodynamic models ( 22 , 36 , 37 ).…”

Microfluidic Formation of Double-Stacked Planar Bilayer Lipid Membranes by Controlling the Water-Oil Interface

“…Furthermore, when we changed the number of pillars from 2 to 4, five-layered flow and double-stacked pBLMs were formed ( Figure S4, Video S3 ). While it is very difficult to observe the surface of pBLMs in our system, because the pBLMs were vertically placed, we expected that the shape of pBLMs is almost square and the pBLMs are surrounded by annulus by reference to a previous work to form the free-standing pBLM by using a microchannel [ 31 ]. By contrast, without guide pillars, five-layered flow was not formed as expected from the simulation.…”

“…Arrayed pBLMs are automatically formed by sequentially flowing aqueous and lipid/oil solutions through microchannels comprising a main flow channel and closed chambers ( Figure S1b ). Furthermore, microfluidic technologies have been applied not only to provide high-throughput platforms but also to increase the stability of the pBLMs and to reduce the noise level for electrophysiological measurements, and to be able to flush/refresh solutions [ 27 , 28 , 29 , 30 , 31 ]. However, these microfluidic methods have not been applied to the formation of multiple-stacked pBLMs.…”