Droplet-interface-bilayer assays in microfluidic passive networks

Abstract

Basic biophysical studies and pharmacological processes can be investigated by mimicking the intracellular and extracellular environments across an artificial cell membrane construct. The ability to reproduce in vitro simplified scenarios found in live cell membranes in an automated manner has great potential for a variety of synthetic biology and compound screening applications. Here, we present a fully integrated microfluidic system for the production of artificial lipid bilayers based on the miniaturisation of droplet-interface-bilayer (DIB) techniques. The platform uses a microfluidic design that enables the controlled positioning and storage of phospholipid-stabilized water-in-oil droplets, leading successfully to the scalable and automated formation of arrays of DIBs to mimic cell membrane processes. To ensure robustness of operation, we have investigated how lipid concentration, immiscible phase flow velocities and the device geometrical parameters affect the system performance. Finally, we produced proof-of-concept data showing that diffusive transport of molecules and ions across on-chip DIBs can be studied and quantified using fluorescence-based assays.

In vitro synthesis of a Major Facilitator Transporter for specific active transport across Droplet Interface Bilayers

“…Although the first examples of DIBs involved only two droplets, manually manipulated, microscale technologies are transforming these systems. Microfluidics devices and 3D printing techniques that allow precise control of the contents and flow rate during droplet formation have been used to make DIBs networks of defined size, composition and spatial distribution that could provide a promising platform for further synthetic biology applications and the development of synthetic tissues101112.…”

Recent Advances in Applications of Droplet Microfluidics

“…Schlicht et al developed a scalable and automated formation of arrays by using droplet-interface-bilayer techniques to imitate cell membrane processes [71]. Recently, Cao et al thoroughly reviewed the toxicological screenings and applied sensing principles of organisms and cells inside microdroplets [72].…”

Droplet Manipulations in Two Phase Flow Microfluidics

“…Another method generates gas bubbles in the channel, and uses the hydrodynamic interaction between bubbles to automatically perform logic operations, forming AND/OR/NOT gates, a toggle flip-flop, a ripple counter, timing restoration and a ring oscillator [109]. As a purely passive technique, a channel geometry has been designed that serves as a shift register for water droplet in oil [110,111]. Very recently, ferrofluidic droplets atop a substrate incorporating multiple permalloy geometries were shown to automatically perform logic operations when a continuous rotating magnetic field is applied [65].…”