Scalable micro-cavity bilayer lipid membrane arrays for parallel ion channel recording

Abstract

a b s t r a c tA compact, scalable and high-throughput bilayer ion channel recording platform capable of simultaneous data acquisition from multiple bilayers is presented. Microfluidic chips house micro-cavities over which bilayers are made; each connected to a custom-made compact electronic readout circuit based on ASICs (Application-Specific Integrated Circuits). The micro-cavities are fabricated using a simple dry-film resist process on a glass wafer. Single 15 mm × 15 mm glass chips contain four separately addressable bilayers, each with integrated Ag/AgCl electrodes. The number of bilayers is scaled by increasing the number of ASICs and four-cavity chips. Each chip can be cleaned and re-used many times and the cavity-suspended lipid bilayers are stable for up to 10 days. System performance is demonstrated with simultaneous electrical recordings of the ion channels gramicidin A and ␣-hemolysin in multiple bilayers.

Screening ion-channel ligand interactions with passive pumping in a microfluidic bilayer lipid membrane chip

“…Without flow, bilayers were stable for 10 days (maximum length of experiment) as presented by authors in an earlier piece of work. 27 With a continuous flow of $0.4-0.5 ll/min, the bilayers were stable for several hours.…”

“…These chips interface with a master board that contains discrete amplifiers for current recording. 27 The chip is made using laminated dry film resist to define both the aperture and the flow channel (Figs. 1(a) and 1(b)).…”

“…Electrical recordings are made using discrete integrated Ag/AgCl electrodes. Each glass chip can hold up to four bilayers, each of which is recorded in parallel, 27 but in this work we use a single aperture. Compared with traditional BLM electrophysiology systems, 11,28,29 both the bilayer and the shunt capacitance are reduced, enabling higher bandwidth low-noise electrical recordings.…”

“…Details of the microfluidic chip fabrication have been described previously 27 (detailed in the supplementary material Fig. S1 (Ref.…”

Microfluidic platform for bilayer experimentation

“…For instance, lifetimes of 15 h were reported for apertures with a diameter of 15-50 µm produced in a 20 µm thick parylene film, 46 this being extended to up to 120 h for sub-micrometer apertures (Figure 2.4 c), 54 and a record of 10 days has been reached for 20-µm size apertures made in TMMF material. 55 However, it is worth mentioning that not only the size of the aperture matters, but also the ratio between the height and the diameter plays an important role for bilayer formation. 56 Furthermore, monitoring bilayer formation in too small structures becomes challenging, since the bilayer capacitance compares with the stray capacitance of the device, 54 and the BLM is not visible anymore.…”