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摘要
Magnetic bead-based biosensors are becoming a hot spot in biomedical fields. A Dynabeads-labeled immunoassay has been developed using a micro fluxgate biosensor for the detection of alpha fetoprotein (AFP) and carcinoembryonic antigen (CEA). The micro fluxgate sensors with a rectangular permalloy core with sides of equal width and three-dimensional solenoid coils are fabricated by microelectro-mechanical-system (MEMS) technology, including thick photoresist lithography and electroplating. The immune reaction of biomarkers is accomplished on a separated Au film substrate surface with a self-assembled layer. Sandwich immunoassay is used to specifically capture and label the biomarker. Dynabeads are conjugated into the biomarker by a streptavidin-biotin system. The micro fluxgate-based sensing system was characterized firstly in different concentrations of Dynabeads. It is found that a concentration as low as 0.1 mu g ml(-1) (90 Dynabeads) can be detected by this sensing system with an external magnetic field in the range of 643 mu T to 1180 mu T. The AFP and CEA with different concentrations were detected by the sensing system. The results reveal that a minimum detectable concentration of 1 pg ml(-1) was achieved in the measuring ranges of 724 mu T to 1150 mu T for AFP, and 670 mu T to 1110 mu T for CEA. Compared with a micro fluxgate sensor with a ribbon core for the detection of biomarkers, the micro fluxgate sensor with an electroplated permalloy core possesses a wider linear measuring range, and could make it possible to integrate a micro fluxgate-based biosensing system produced on a large scale, with an expanded application field and reduced costs.
- 出版日期2015
- 单位上海交通大学
