Kasumi Ikegami

A miniature Clark-type oxygen electrode using a polyelectrolyte and its application as a glucose sensor

A miniature Clark-type oxygen electrode was fabricated by anisotropically etching silicon. A two-gold-electrode configuration was used and a double-layered gas-permeable membrane was formed directly on the electrolyte, poly(vinyl-4-ethylpyridinium bromide) in the sensitive area. These materials improved the electrodes stability in long-term storage and sterilization tolerance to a practical level. The 90% response time averaged 80 s and residual current 10%, with a good linear calibration curve. The oxygen electrode was also used to make an integrated sensor for the simultaneous determination of glucose and oxygen. The glucose sensors response time was 50-110 s, with good linearity in glucose concentrations between 56 microM and 1.1 mM at 37 degrees C, pH 7.0.

Disposable oxygen electrodes fabricated by semiconductor techniques and their application to biosensors

Abstract We fabricated a miniature Clark-type oxygen electrode using semiconductor techniques. The oxygen electrode features V-grooves to contain a 0.1 M KCl electrolyte impregnated in a gel, and a directly formed gas-permeable membrane over the gel. A fast response and a good linearity from zero oxygen concentration to saturation was obtained using the Ag/AgCl anode. The oxygen electrode was used in a disposable miniature CO 2 sensor. Also, an l -lysine sensor was developed that functions by immobilizing l -lysine decarboxylase on the sensitized area of the CO 2 sensor.

Holographic Recording Material Containing Poly-N-vinylcarbazole

A volume phase holographic recording material with high diffraction efficiency and high durability against humidity has been developed. The holographic material consists of Poly-N-vinylcarbazole (PVCz) as a base polymer, camphorquinone as an initiator and thioflavine-T as a sensitizer. This film is sensitive to argon ion laser light, and exposure energy of 500 mJ/cm2 is required to realize high diffraction efficiency. After recording a latent image of a fringe pattern by exposure, a hologram was developed by swelling and shrinking of the film with two sorts of solvent. The thickness of the hologram could be reduced to 2.5 μm, because the PVCz hologram has a large amplitude of the refractive index modulation related with the crystallinity modulation. The high diffraction efficiency coupled with the thin layer made an incident light angle wide enough to maintain a high diffraction efficiency around the Bragg angle.

Photoconduction of Copper Phthalocyanine-Binder Photoconductor Sensitized with Poly-N-vinylcarbazole

A nontoxic organic photoconductor for near infrared light has been developed. It consists of poly-N-vinylcarbazole (PVCz) dispersed in a copper phthalocyanine (CuPc)-binder resin system. PVCz has been selected from among several electron donating compounds that are considered to be able to reduce the induction period (TN) that is a typical imperfection of the binary system. The optimum mixing ratio of the three components (CuPc, PVCz, and a binder resin) was determined after examining film-forming ability, charge acceptance, and exposure energy for half-decay of the surface potential (E1/2). The photoconductor, composed of E-crystal form of CuPc (40 wt/%), PVCz (10 wt/%), and a polyester binder resin (50 wt/%), has an E1/2 of 3.2 , ¿J/cm2 at a light of 760 nm. It has a charge acceptance of 800 V, in accordance with the p-type. conduction of CuPc, when a positive surface charge is used.