On-Chip Enzyme Immunoassay of a Cardiac Marker Using a Microfluidic Device Combined with a Portable Surface Plasmon Resonance System

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• 作者：Ryoji Kurita ; Yoshimi Yokota ; Yukari Sato ; Fumio Mizutani ; Osamu Niwa
• 刊名：Analytical Chemistry
• 出版年：2006
• 出版时间：August 1, 2006
• 年：2006
• 卷：78
• 期：15
• 页码：5525 - 5531
• 全文大小：272K
• 年卷期：v.78,no.15(August 1, 2006)
• ISSN：1520-6882

文摘

This paper reports a miniaturized immunosensor designed to determine a trace level cardiac marker, B-typenatriuretic peptide (BNP), using a microfluidic devicecombined with a portable surface plasmon resonance(SPR) sensor system. Sample BNP solution was introduced into the microchannel after an immunoreactionwith acetylcholine esterase-labeled antibody (conjugate),and only unbound conjugate was trapped on the BNP-immobilized surface in the flow channel. Then, the thiolcompound generated by the enzymatic reaction with thetrapped conjugate was accumulated on a gold thin filmlocated downstream in the microchannel to monitor thereal-time SPR angle shift. We achieved a detectableconcentration range of 5 pg/mL-100 ng/mL by monitoring the SPR angle shift, which covers the required detection range for the BNP concentrations found in blood. Thissuccess resulted from the use of a T-shaped microfluidicdevice structure, which prevents the sample solution fromflowing over the gold film used for SPR detection. We wereable to measure trace levels of BNP peptide (15 fg) within30 min since the procedure with our immunosensor issimpler than a multistep immunoassay through the simultaneous use of a labeled enzymatic reaction and thereal-time monitoring of enzymatic product accumulationin the microfluidic device. We employed the procedureto detect serum BNP by using spiked samples in humanserum and achieved satisfactory recovery for heat-treatedsamples to denature the esterase in the serum before theimmunoreaction.