Takashi Shiro

A device for visual detection of antigens and antibodies by means of light interference

Abstract A device for visual detection of antigens and antibodies was investigated. The device is composed of a light-reflecting substrate, a light-interfering layer and an immobilized antibody (antigen) layer. The detection is based on the colour change due to light interference before and after reaction of the immobilized antibody (antigen) with antigen (antibody) in an aqueous specimen. Theoretical analysis of the light interference suggested that the application of a light-reflecting layer on the surface of the device after an antigen-antibody reaction is effective for both glancing angle and clarity. Colloidal gold was found to be a good candidate for the layer. With a device of Ferrotype TM /SiO 2 (1000 A)/(mixed monomolecular film of anti-human IgG and methyl arachidate), 1 × 10 −7 g ml −1 of human IgG could be visually detected from the normal direction of the device.

Laser doping of boron-doped Si paste for high-efficiency silicon solar cells

Boron laser doping (LD) is a promising technology for high-efficiency solar cells such as p-type passivated locally diffused solar cells and n-type Si-wafer-based solar cells. We produced a printable phosphorus- or boron-doped Si paste (NanoGram® Si paste/ink) for use as a diffuser in the LD process. We used the boron LD process to fabricate high-efficiency passivated emitter and rear locally diffused (PERL) solar cells. PERL solar cells on Czochralski Si (Cz-Si) wafers yielded a maximum efficiency of 19.7%, whereas the efficiency of a reference cell was 18.5%. Fill factors above 79% and open circuit voltages above 655 mV were measured. We found that the boron-doped area effectively performs as a local boron back surface field (BSF). The characteristics of the solar cell formed using NanoGram® Si paste/ink were better than those of the reference cell.

A highly sensitive device for visual detection of antigens and antibodies by means of light interference

Abstract A highly sensitive device for the visual detection of antigens and antibodies by means of light interference has been investigated. The detection is based on the change in the light interference colour after the antigen-antibody reaction of an immobilized antibody (antigen) with an antigen (antibody) in a specimen. We investigate selective staining of the antibody part by colloidal gold treatment at an optimized pH value (colloidal gold method). We have also investigated selective staining of the antigen part on the immobilized antibody by treatment with a secondary antibody bearing colloidal gold (sandwich method). Both methods are found to enhance the sensitivity. According to the colloidal gold method, less than 1 ng/ml of anti-hCG can be visually detected by using a device with immobilized hCG. With the sandwich method, 1 ng/ml of human IgG can be visually detected by using a device with immobilized anti-human IgG.

LB film immobilized immunosensor with a charge detection type amplifier

Abstract In order to fabricate a miniturized solid-state sensor, a novel potentiometric immunosensor was designed by incorporating a new amplification system of charge detection type and an electrode covered with immunogloblin-G (IgG, antigen) immobilized in a Langmuir-Blodgett (LB) film. A surface potential change of 1 μV generated by the immuno-reaction between IgG and anti-IgG (antibody) could be measured with the amplification system, which made it possible to detect the anti-IgG with concentrations less than 5 x 10-8M. The intensity of surface potential change observed in the reaction was successfully correlated with the activity of the immobilized IgG by using luminescent enzyme immunoassay.

Plastic substrate technologies for flexible displays

A novel plastic substrate for flexible displays was developed. The substrate consisted of a polycarbonate (PC) base film coated with a gas barrier layer and a transparent conductive thin film. PC with ultra-low intrinsic birefringence and high temperature dimensional stability was developed for the base film. The retardation of the PC base film was less than 1 nm at a wavelength of 550 nm (film thickness, 120 μm). Even at 180 °C, the elastic modulus was 2 GPa, and thermal shrinkage was less than 0.01%. The surface roughness of the PC base film was less than 0.5 nm. A silicon oxide (SiOx) gas barrier layer was deposited on the PC base film by a DC magnetron reactive sputtering method. In addition, a unique organic-inorganic hybrid material is coated on the SiOx to further improve the gas-barrier performance. The water vapor transmission rate of the film was less than 0.05 g/m2/day at 40 °C and 100% relative humidity (RH), and the permeation of oxygen was less than 0.05 cc/m2•day•atm at 40 °C and 90% RH. Indium Zinc Oxide optimized for the plastic substrate was deposited on the other side of the SiOx film by the DC magnetron sputtering method. The transmittance was 87% and the resistivity was 3.5×10-4 ohm•cm.

59.4: Novel Retardation Film with Nano‐Scale Multi‐Layered Structure

We have developed a novel Z-plate with nano-scale multi-layered structure. The optically biaxial characteristics (nx<nz<ny) of that Z-plate is controlled by the combination of form birefringence and molecular orientation birefringence. The novel retardation film has been realized by new optical design and a new film process with a multi-layered polymer extrusion device.

A novel method of visual detection of antigens and antibodies by means of light interference

A novel method for detection of antigens and antibodies is proposed. The detection is based on the color change due to the light interference upon the antigen-antibody reaction with an antibody (or antigen) immobilized on a substrate with a light interference layer. By theoretical analysis, the application of a light-reflecting layer (colloidal gold) to the device after the reaction was found to be effective to visualization and contrast. With immobilized anti-human IgG, 1·10−7 g/ml of human IgG was sucessfully detected.