• Analytical Science and Technology
• /
• v.5 no.2
• /
• pp.177-184
• /
• 1992

A preparation method and response characteristics of a glucose sensor which consisted of pH-ISFET and glucose oxidase-immobilized membrane were investigated. The pH-ISFET glucose sensor was fabricated by immbilizing bovine serum albumin and glucose oxidase with glutaraldehyde on gate of the pH-ISFET. Effects of pH and concentration of working buffer and enzyme load on the pontentiometric response of the pH-ISFET glucose sensor were examined. Response characteristics for the determination of glucose in synthetic physiological saline solution(pH 7.4) were as follows. That is the concentration range of linear response, slope of linear response(sensitivity), and response time were $1.0{\times}10^{-4}{\sim}6.0{\times}10^{-3}M $, 4.1 mV/decade, and 12~15 min., respectively.

• Journal of Sensor Science and Technology
• /
• v.7 no.4
• /
• pp.271-278
• /
• 1998

A ISFET-based glucose sensor has inherent problems such as low sensitivity, drift effect and long response time. For that reason, a amperometric actuation technique was introduce to make a highly sensitivity of the ISFET glucose sensor with a Pt actuator, which electrolyzes $H_2O_2$, one of the by a by-products of the oxidation reaction of glucose. Moreover, a potential-step measurement method detecting response by only the electrolysis of $H_2O_2$ was developed for eliminating a drift problem. The operation characteristics of ISFET-based glucose sensor was improved by using the amperometric actuation and a measurement techniques. The fabricated ISFET glucose sensor is shown good operation such as characteristics(30mM PBS, about 26mV/decade) and linearity. A portable glucose meter with a highly resolution by using the fabricated ISFET-based glucose sensor with Pt actuation was developed and its characteristics investigated.

• Journal of Sensor Science and Technology
• /
• v.1 no.2
• /
• pp.101-106
• /
• 1992

pH-ISFETs, the semiconductor pH sensors, were combined with immobilized enzyme membranes to prepare FET type urea and glucose sensors and its operational characteristics were investigated. Photolithography techniques were applied to immobilize enzymes on the $H^{+}$ sensing membrane of the pH-ISFET with photo-sensitive polymers, PVA-SbQ. Fabricated urea and glucose sensors could determine $0.5{\sim}50{\;}mg/dl$ urea concentrations and $10{\sim}1000{\;}mg/dl$ glucose concentrations, respectively.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.29A no.4
• /
• pp.58-63
• /
• 1992

Photolithography techniques were applied for immobilization of GOD membrane on the pH-ISFET with photo-sensitive polymers to realize ISEFT glucose sensor. This IC technology-compatible glucose sensor showed good sensing characteristics in the wide range of 10-1000 mg/dl glucose concentrations.

• Proceedings of the IEEK Conference
• /
• 2005.11a
• /
• pp.755-758
• /
• 2005

This paper describes the novel immunoassay sensing system for a portable clinical diagnosis system. It consists of a bead cage reactor and a CMOS integrated biosensor. It showed the simple and easy antibody coating method on beads by flow-through avidin biotin complex technology in a microfluidic device. It showed just 90 nL sample consumption and good result for the application of alpha feto protein. The bead cage reactor has the role of the antibody coating, antigen binding and enzyme linking for the electrochemical sensing method. The CMOS biosensor consists of ISFET (ion selective field effect transistor) biosensor and temperature sensor for detecting pH that is the byproduct of enzyme reaction. The sensitivity is 8 $kHz/^{\circ}C$ in a temperature sensor and 33 mV/pH in a pH sensor. After filling the 15 um polystyrene beads in bead cage, antibody flowed and reacted to beads. Subsequently, the biotinylated antigen flowed and bound to the antibody and GOD (glucose oxidase)-avidin conjugate flowed and reacted to the biotin of the biotinylated antigen. After this reaction process, glucose solution flowed and reacted to the GOD on beads. The hydrogen was generated by glucose-GOD reaction. And it was detected by the pH sensor.