Enhancement of membrane protein reconstitution on 3D free-standing lipid bilayer array in a microfluidic channel

The bio-sensory organs of living creatures have evolved to have the best sensing performance. They have 3-dimensional protrusions that have large surface areas to accommodate a large number of membrane proteins such as ion channels and G-protein coupled receptors, resulting in high sensitivity and specificity to target molecules. From the perspective of mimicking this system, BLM, which has been used extensively as a platform for a single nanopore-based sensing systems, has some limitations, i.e., some residual solvent, low mechanical stability, small surface area for appropriate stability, and difficulty in high-throughput fabrication. Herein, to eliminate these limitations, a solvent-free, size-controllable, 3-dimensional free-standing lipid bilayer (3DFLB) structure array with high stability (∼130 h) and high density (∼300,000 cm^-2) is proposed, and its structural advantages for efficient and rapid protein reconstitution, compared to BLM, is demonstrated by human 5-HT_3A receptor assay as well as α-hemolysin assay. A continuous process of 3DFLB array fabrication, 5-HT_3A reconstitution, and 5-HT detections in a microfluidic channel proves the applicability of the proposed structures as a highly-sensitive sensing platform mimicking bio-sensory organs.