An automated ELISA system using a pipette tip as a solid phase and a pH-sensitive field effect transistor as a detector.

A fully automated ELISA system was constructed using a pipette tip as a solid phase, urease as a detecting enzyme, and a pH-FET as a detector of urease activity. The inner wall of the end part of a pipette tip was used as a solid phase, and the urease activity of the conjugate, captured after a two-step immunoreaction, was measured by coupling the pipette tip with the pH-FET in a pH-measuring cell. Full automation of the ELISA system was achieved by using a disposable reagent cartridge and three pipetters for all mechanical operations, including sample dilution and B/F separation. This system can treat 60 samples per hour with an assay time of 21 min for all assay configurations. The system was applied to two-step sandwich assays for AFP, CEA, HBsAg, and HBsAb, a two-step competition assay for HBcAb, and a second antibody assay for HTLV-I Ab.

[1]  I. Weeks,et al.  Chemiluminescence immunoassay: an overview. , 1986, Clinical science.

[2]  J. Gosling.  A decade of development in immunoassay methodology. , 1990, Clinical chemistry.

[3]  M. Nakamura,et al.  Online pH,pCO2 andpO2 monitoring system using two-way cyclic pumping of lactate Ringer as a baseline solution , 2006, Medical and Biological Engineering and Computing.

[4]  J. Cox,et al.  A rapid semi quantitative capillary enzyme immunoassay for digoxin. , 1983, Clinica chimica acta; international journal of clinical chemistry.

[5]  P Bergveld,et al.  Development of an ion-sensitive solid-state device for neurophysiological measurements. , 1970, IEEE transactions on bio-medical engineering.

[6]  H. Kiyokawa,et al.  Detection of antibodies to human T‐lymphotropic virus type I by using synthetic peptides , 1990, International journal of cancer.

[7]  K. Healey,et al.  Monoclonal hybridoma antibodies against human IgE and their use in a rapid and sensitive enzyme immunoassay for the semiquantitative assessment of total IgE levels in human blood. , 1983, International archives of allergy and applied immunology.

[8]  J. Hurrell,et al.  A new enzyme immunoassay system suitable for field use and its application in a snake venom detection kit. , 1982, Clinica chimica acta; international journal of clinical chemistry.

[9]  M. Meyerhoff,et al.  [29] Electrode-based enzyme immunoassays using urease conjugates , 1980 .

[10]  J. Corrie,et al.  Immunoassays for clinical chemistry , 1983 .

[11]  L. Kricka,et al.  Chemiluminescent enzyme immunoassay of alpha-fetoprotein based on an adamantyl dioxetane phenyl phosphate substrate. , 1989, Clinical chemistry.

[12]  A. Kohama,et al.  Continuous monitoring of arterial and tissue Pco2 , 1984, Critical Care Medicine.

[13]  J. Briggs.  Biosensors emerge from the laboratory , 1987, Nature.

[14]  E. Sheldon,et al.  Picogram quantitation of total DNA using DNA-binding proteins in a silicon sensor-based system. , 1990, Analytical biochemistry.

[15]  M. Meyerhoff,et al.  Electrode-Based Enzyme Immunoassays usings urease conjugates. , 1979, Methods in enzymology.