title: Planar Hall magnetoresistive aptasensor for thrombin detection.
abstract: The use of aptamer-based assays is an emerging and attractive approach in disease research and clinical diagnostics. A sensitive aptamer-based sandwich-type sensor is presented to detect human thrombin using a planar Hall magnetoresistive (PHR) sensor in cooperation with superparamagnetic labels. A PHR sensor has the great advantages of a high signal-to-noise ratio, a small offset voltage and linear response in the low-field region, allowing it to act as a high-resolution biosensor. In the system presented here, the sensor has an active area of 50 µm × 50 µm with a 10-nm gold layer deposited onto the sensor surface prior to the binding of thiolated DNA primary aptamer. A polydimethylsiloxane well of 600-µm radius and 1-mm height was prepared around the sensor surface to maintain the same specific area and volume for each sensor. The sensor response was traced in real time upon the addition of streptavidin-functionalized magnetic labels on the sensor. A linear response to the thrombin concentration in the range of 86 pM-8.6 µM and a lower detection limit down to 86 pM was achieved by the proposed present method with a sample volume consumption of 2 µl. The proposed aptasensor has a strong potential for application in clinical diagnosis.
authors.affiliation: Department of Materials Science and Engineering, Chungnam National University, Daejeon 305-764, South Korea.
authors.forename: B
authors.initials: B
authors.lastname: Sinha
authors.affiliation: Department of Materials Science and Engineering, Chungnam National University, Daejeon 305-764, South Korea; Department of Emerging Materials, Daegu Gyeongbuk Institute of Science and Technology, Daegu 711-873, South Korea.
authors.forename: T S
authors.initials: TS
authors.lastname: Ramulu
authors.affiliation: Department of Materials Science and Engineering, Chungnam National University, Daejeon 305-764, South Korea; Department of Emerging Materials, Daegu Gyeongbuk Institute of Science and Technology, Daegu 711-873, South Korea.
authors.forename: K W
authors.initials: KW
authors.lastname: Kim
authors.affiliation: Department of Materials Science and Engineering, Chungnam National University, Daejeon 305-764, South Korea; Department of Emerging Materials, Daegu Gyeongbuk Institute of Science and Technology, Daegu 711-873, South Korea.
authors.forename: R
authors.initials: R
authors.lastname: Venu
authors.affiliation: Nano-Mechanical Systems Research Division, Korea Institute of Machinery & Materials, Daejeon 305-600, South Korea.
authors.forename: J J
authors.initials: JJ
authors.lastname: Lee
authors.affiliation: Department of Materials Science and Engineering, Chungnam National University, Daejeon 305-764, South Korea; Department of Emerging Materials, Daegu Gyeongbuk Institute of Science and Technology, Daegu 711-873, South Korea. Electronic address: cgkim@dgist.ac.kr.
authors.forename: C G
authors.initials: CG
authors.lastname: Kim
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation*; D004867:Equipment Design; D006801:Humans; D057230:Limit of Detection; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D013917:Thrombin / Q000032:analysis*
chemical_list: D052157:Aptamers, Nucleotide; D058185:Magnetite Nanoparticles; C081676:thrombin aptamer; D013917:Thrombin
keywords: Aptasensor; Planar Hall magnetoresistive sensor; Sandwich; Thrombin