Magneto-Controlled Graphene Immunosensing Platform for Simultaneous Multiplexed Electrochemical Immunoassay Using Distinguishable Signal Tags

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• 作者：Juan Tang ; Dianping Tang ; Reinhard Niessner ; Guonan Chen ; Dietmar Knopp
• 刊名：Analytical Chemistry
• 出版年：2011
• 出版时间：July 1, 2011
• 年：2011
• 卷：83
• 期：13
• 页码：5407-5414
• 全文大小：1043K
• 年卷期：v.83,no.13(July 1, 2011)
• ISSN：1520-6882

文摘

A novel flow-through multiplexed immunoassay protocol for simultaneous electrochemical determination of carcinoembryonic (CEA) and alpha-fetoprotein (AFP) in biological fluids was designed using biofunctionalized magnetic graphene nanosheets (MGO) as immunosensing probes and multifunctional nanogold hollow microspheres (GHS) as distinguishable signal tags. The probes were fabricated by means of co-immobilization of primary anti-CEA (Ab₁) and anti-AFP (Ab₂) antibodies on the Fe₃O₄ nanoparticle-coated graphene nanosheets (MGO-Ab_1,2). The reverse-micelle method was used for the synthesis of distinguishable signal tags by encapsulation of horseradish peroxide (HRP)-thionine and HRP-ferrocene into nanogold hollow microspheres, respectively, which were utilized as labels of the corresponding GHS-Ab₁ and GHS-Ab₂. A sandwich-type immunoassay format was employed for the online detection of CEA and AFP by coupling a flow-through detection cell with an external magnet. The assay was based on the catalytic reduction of H₂O₂ at the various peak potentials in the presence of the corresponding mediators. Experimental results revealed that the multiplexed electrochemical immunoassay enabled the simultaneous monitoring of AFP and CEA in a single run with wide working ranges of 0.01鈥?00 ng mL^鈥? for AFP and 0.01鈥?0 ng mL^鈥? for CEA. The detection limits (LODs) for both analytes at 1.0 pg mL^鈥? (at 3s_B) were very low. No obvious nonspecific adsorption and cross-talk were observed during a series of analyses to detect target analytes. Intraassay and interassay coefficients of variation were <10%. Importantly, the methodology was evaluated for the analysis of clinical serum specimens, receiving a good correlation between the flow-through multiplexed electrochemical immunoassay and an electrochemiluminescence method as a reference.