Ryuji Kawano

A parylene nanopore for stable planar lipid bilayer membranes

This paper describes a microfluidic device for a high through-put ion channel recordings, in which planar bilayer lipid membranes (BLMs) are spanning across a nanometer-sized poly(p-xylylene) (parylene) pore (Figure 1). To make the nanopore, a micrometer-sized pore of parylene was prepared by photolithography, and then parylene was additionally deposited on to the micropore with the isotropic vaporization. As a result, we successfully obtained an 800 nm diameter pore in the parylene film. In addition, BLM was able to be formed stably at the parylene nanpores that was built into the microfluidic device with upper and lower fluidic channels. We also demonstrated to reconstitute of alpha-hemolysin (αHL) into the BLMs. This device will provide a high reliability platform for the ion-channel recordings.

Mechanical pumpless giant liposome trapping system using parylene micro filter for biological assay

This paper proposes a non-chemical, mechanical giant liposome trapping method using a parylene filter with micrometer-order-sized holes. Giant liposomes can be useful reaction sites for biological assays, where immobilization of the liposomes is the key protocol for microscopic observation. The proposed mechanical trapping method using the parylene filter and gentle flow does not require pretreatments on the liposomes that are time consuming and costly. In addition, this method does not strongly bind but only traps the liposomes, which allows the liposomes to be chemically treated while being trapped and then, to be released. We demonstrated size-dependent trapping, solution exchange and releasing of liposomes. The proposed trapping method and microfluidic device are readily applicable to highly efficient giant liposome assays.

Horizontal lipid bilayers formed by droplets contact method on patterned micro-droplets

We developed horizontal lipid bilayers by the Droplets Contact Method (DCM). DCM is the easiest and most efficient method to form lipid bilayers. However, the lipid bilayers formed by our previous method could not be used for simultaneous electrophysiological and optical measurements because the bilayers are vertically oriented and therefore optically invisible. We performed DCM on patterned micro-droplets, so that the horizontal lipid bilayers were obtained. We visualized the lipid bilayer formation by an optical microscope and detected the current signals of the pore-forming membrane protein, α-hemolysin.