Immunoassay systems based on immunoliposomes consisting of genetically engineered single-chain antibody

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• 作者：Kobatake ; Eiry ; Yun ; Kyusik ; Yanagida ; Yasuko ; Haruyama ; Tetsuya ; Kein&auml ; nen ; Kari ; Aizawa ; Masuo
• 关键词：Immunoliposome ; Single-chain antibody ; Fluoroimmunoassay ; Quartz crystal microbalance ; Atomic force microscopy
• 刊名：Sensors and Actuators B: Chemical
• 出版年：2000
• 出版时间：June 30, 2000
• 年：2000
• 卷：65
• 期：1-3
• 页码：42-45
• 全文大小：161 K

文摘

The single-chain antibody against 2-phenyloxazolone was modified with lipid molecules at its amino-terminus by genetic engineering. The engineered lipid-tagged antibody molecules were incorporated into liposomes consisting of phosphatidylcholine, and the immunoassay systems were constructed by the resulting immunoliposomes. One immunoassay system was based on fluoroimmunoassay. A competitive fluoroimmunoassay for caproic acid conjugate of 2-phenyloxazolone as a model antigen was performed with the calboxyfluoresceine-encapsulated immunoliposomes. Antigen could be determined in the concentration range from 10⁻⁷ to 10⁻⁹ M. The other system was based on quartz crystal microbalance (QCM). The immunoliposomes were competitively reacted with analyte to the hapten-immobilized surface of a crystal plate. The frequency change was observed by injection of the mixture of the immunoliposomes and analyte in a concentration dependent manner. In this competitive QCM assay, antigen could be measured in the concentration range from 10⁻⁵ to 10⁻⁸ M. Furthermore, direct observation of the immunoliposomes on the hapten-coated solid-surface by atomic force microscopy (AFM) was also performed in this study.