Etsuo Shinohara

Free-flow electrophoresis in a microfabricated chamber with a micromodule fraction separator. Continuous separation of proteins.

Continuous free flow electrophoresis of proteins was carried out in a microfabricated free flow electrophoresis (mFFE) module with the 30-microm thick slit of the separation. The newly developed micromodule fraction separator (MFS) was attached to the down-stream end site of the separation chamber of mFFE. By using the MFS, electrolyte solution from the separation chamber was introduced to the peristaltic pump without disturbing the electrolyte solution flow at the bottom side of the chamber. The separation of protein mixture samples was achieved by a hydroxypropylmethylcellulose pretreatment coating of the separation chamber. The pretreatment of the sample chamber effectively suppressed electroosmotic flow. All fractionated samples were collected using the MFS after continuous elecrophoresis and analyzed by reversed-phase HPLC. From the results of HPLC analyses none of the cytochrome c fractions at the other ports revealed cross talk phenomena at adjacent ports. A similar result occurred for the myoglobin. This means that these proteins were completely separated from each other by continuous mFFE, and the MFS functioned efficiently during continuous electrophoresis.

Effect of thermal treatment on crystal growth of the surface monolayer

Abstract In order to anneal the surface monolayer uniformly, a new trough system with a flat panel heater and a fluorescence microscope was constructed. The recrystallization process during thermal treatment of the monolayer was directly monitored by a fluorescence microscope. The crystal size of a double-chain ammonium monolayer was extremely increased by the thermal treatment. The practical advantage of the flat panel heater on the thermal treatment was demonstrated as a uniform size distribution of the crystalline domains.

Effect of thermal treatment on surface monolayer and Langmuir-Blodgett film prepared by polyion complex technique

Abstract A stable monolayer of a polymeric ion complex was formed at the air-water interface when dioctadecyldimethylammonium bromide was spread on an aqueous solution of potassium poly(vinyl sulphate). The polyion-complexed monolayer was annealed by a flat-panel heater located above the surface monolayer. The annealed monolayer deposited on an indium tin oxide electrode as a Y-type Langmuir-Blodgett film effectively blocked the electrochemical oxidation-reduction reaction of the ferricyanide ion.

Selective ion-sensing based on Langmuir-Blodgett films having potential sensitive dyes. Effect of monolayer matrix on host-guest interaction of valinomycin with potassium ion

Abstract Surface pressure-area isotherms of anionic monolayers, arachidic acid and didodecylphosphate, containing valinomycin and a potential sensitive dye were measured on both KCl and NaCl subphases. The isotherm indicated that a phase separated cluster of valinomycin was formed in the arachidic acid monolayer. Fluorescence imaging of the surface monolayer with a newly constructed fluorescence microscope attached to a Langmuir film balance proved phase separation in the arachidic acid monolayer. The isotherm of arachidic acid on a KCl subphase was very similar to that on the NaCl subphase, but a small contraction was found on the KCl subphase. An isotherm of a valinomycin monolayer complexed with potassium ion, however, was more expansive than that for pure valinomycin. A large expansion in the isotherm observed in a mixed monolayer with didodecylphosphate suggested that valinomycin was homogeneously distributed in the fluid monolayer matrix. The isotherm on the KCl subphase was very different from that...

Design of ion sensor based on Langmuir-Blodgett films having potential-sensitive dye: effect of surface treatment of solid substrate on potassium-ion sensing

Wolfbeis and Schatfer prepared ion-selective optrodes based on Langmuir-Blodgett (LB) tilms containing ionspecific ionophores and potential-sensitive dyes [l, 21. The ion was detected as a change of the membrane potential, which was monitored by measuring the fluorescence change of the potential dye. By using a newly constructed fluorescence microscope attached to a Langmuir fihn balance [3], we have succeeded in improving the sensing ability of the LB fihu optrodes [4,5]. The membrane potential and the sensing ability of the LB tihn are intrinsically influenced by the lihn properties. The surface of the solid substrate used for the film deposition is one of the most important factors in determining properties of the &II. In this paper, the effects of surface treatment of the quarts substrate on the tihn preparation and the sensing ability are investigated.

Multi Micro Reactors Consist of Individually Temperature Controlled Silicon Well Arrays Realizing Efficient Biochemical Reactions

8 × 12 multi micro reactors to realize efficient biochemical reactions were designed and fabricated. It has 12 lines of 8 micro well columns that have series heaters and temperature sensors to obtain PID temperature control. The sizes of each micro well are 2 mm × 2 mm, 500 µm in depth and 1.4 µl in volume. This enables many biochemical reactions under different temperature conditions at the same time. Finite element thermal analysis was performed to achieve precise and efficient temperature control of each well with smaller power consumption.

A New Application by Microfabricated Free Flow Electrophoresis Module

Using anion and cation dyes, separation and interaction between those dyes was investigated with a microfabricated free flow electrophoresis (FFE) module. Crossing the sample stream of dye solution in the separation bed of the FFE, interaction strength of two dyes was evaluated. The results suggested that the FFE module could use as a microreactor.

Continuous Free-Flow Electrophoresis Separation of Proteins by Microfabricated Chamber with Micromodule Fraction Separator

The technology of free flow electrophoresis (FFE) is now more than 40 years old [1] and the field is now experiencing a new development through microfabricated free flow electrophoresis (mFFE) module [2]. This paper will describe one system’s development and application of mFFE technology.

Free Flow Electrophoresis Module for Rapid Sample Preparation

Newly designed FFE modules and a control system were developed. The separation time during the sample flow from the inlet to the outlets was one second when a mixture of genomic DNA, plasmid and albmin was used as a sample. Very high-speed separation and collection system was realized by the microfabricated FFE module.

Free Flow Electrophoresis Module Fabricated with Pyrex Glass

In this study a free flow electrophoresis (FFE) module was constructed as a preparatory unit of the system to separate DNA from other contaminants in the specimens. The FFE module was made from Pyrex glass to apply high voltages and fabricated on a 4inch glass wafer that is easily processed by the semiconductor fabrication technology. The size of the module was 66x70mm, in which 47x40mm separation bed with 10 or 50 μm deep flow gap was constructed. Six inlets for buffer and one for the specimen at the head part and 30 outlets for collection of separated fractions were built at the tail part. Two gold wire electrodes were fixed to the both edges parallel to its flow direction. Flow of buffer and specimens was observed under a videocamera and all experiments were performed at a flow rate of 10mm/sec. To investigate its function a mixture of genomic DNA, plasmid, albumin and globulin in Tris-Hcl buffer of pH8 was applied to the F.F.E. with 1kv. The genomic DNA and plasmid were recovered from outlets 5&6, albumin from outlets 6&7 and globulin from 7&8.