Papers - SAKAI Go
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Selective and repeatable detection of human serum albumin by using piezoelectric immunosensor
Sakai G., Saiki T., Uda T., Miura N., Yamazoe N.
Sensors and Actuators: B. Chemical 24 ( 1-3 ) 134 - 137 1995.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Sensors and Actuators: B. Chemical
Improvements of the sensitivity and stability of a piezoelectric immunosensor for human serum albumin (HSA) have been examined. A change in resonance frequency (ΔF: sensitivity) is observed when an HSA solution is allowed to flow onto a quartz-crystal sensor immobilized with anti-HSA monoclonal antibody. ΔF is found to increase further by about three times upon subsequent exposure to a flow of the polyclonal antibody solution owing to the formation of a complex of HSA sandwiched between the two types of antibody. The final value of ΔF varies almost linearly with the HSA concentration in the range 0-20 ppm, with a sensitivity of ≈ Hz ppm-1. The resonance frequency returns reversibly to the initial level on exposure to an acidic buffer solution (pH 3.0). Furthermore, the measurement of HSA can be repeated up to about 30 times with the same sensor without a significant change in sensitivity. These results confirm that the sensor has sufficient sensitivity as well as good repeatability to be applied to a liquid flow-type HSA assay system. © 1995.
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Selective Detection of HSA (Human Serum Albumin) by Piezoelectric Immunosensor Reviewed
共著者：G. Sakai, T. Saiki, T. Uda, N. Miura, Yamazoe
Sensors and Actuators B, Vol. 24-25, 134-137 24-25 134 - 137 1995.3
Language：English Publishing type：Research paper (scientific journal)
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Miura N., Higobashi H., Sakai G., Takeyasu A., Uda T., Yamazoe N.
Sensors and Actuators: B. Chemical 13 ( 1-3 ) 188 - 191 1993.5
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Sensors and Actuators: B. Chemical
We have developed an immunosensor based on a piezoelectric quartz resonator, which detects methamphetamine (MA) in liquids from a shift of the resonant frequency. The sensor has MA-albumin conjugates immobilized on the resonator and its resonant frequency shifts downward on contact with the monoclonal antibody to MA dissolved in the phosphate buffer solution. Under the condition of a fixed concentration of the antibody, the frequency shift is attenuated by mixing MA with the antibody solution. Based on this principle, it has been possible to detect 0.02-100 ppm MA with a detection time of about 7 min. The sensor has proved to be sensitive and stable enough to detect the critical concentration (1 ppm) of MA in human urine. © 1993.
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Piezoelectric Crystal Immunosensor for Sensitive Detection of Methamphetamine (Stimulant Drug) in Human Urine Reviewed
共著者：N. Miura, H. Higobashi, G. Sakai, A. Takeyasu, T. Uda, N. Yamazoe
Sensors and Actuators B, Vol. 13-14, 188-191 13-14 188 - 191 1993.5
Language：English Publishing type：Research paper (scientific journal)
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Miura N., Minamoto H., Sakai G., Yamazoe N.
Sensors and Actuators: B. Chemical 5 ( 1-4 ) 211 - 217 1991.8
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Sensors and Actuators: B. Chemical
A new type of piezoelectric crystal sensor coated with a sputtered noble metal (Pt, Pd, Ir, or Pt-Ir) film is proposed for the detection of inflammable gases, such as H2, CO and isobutane diluted with air, in the temperature range 100-400 °C. Its sensing principle utilizes an increase in resonance frequency of the quartz crystal with the increase in temperature due to the oxidation of an inflammable gas on the coated catalyst film. Experiments show that the sensitivity increases linearly with H2concentration up to 0.4 vol.%, with a 90% response time of about 20 s to 0.3 vol.% H2at 200 °C. The sensitivity is dependent on the operation temperature due to the temperature-dependent resonance frequency of the crystal. Among the various coating films tested, sputtered Pt-Ir film gives the best sensor, with high sensitivity to inflammable gases and high resistance to interference by coexisting water vapour. © 1991.
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New Type Calorimetric Gas Sensor Using Temperature Characteristics of Piezoelectric Quartz Crystal Fitted with Noble Metal Catalyst Film Reviewed
共著者：N. Miura, H. Minamoto, G. Sakai, N. Yamazoe
Sensors and Actuators B, Vol. 5, 211-217 5 211 - 217 1991.8
Language：English Publishing type：Research paper (scientific journal)