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2008 Design of Medical Devices Conference Abstracts

Construction of a Magnetic Biosensor for Pathogen Detection OPEN ACCESS

[+] Author and Article Information
Yuanpeng Li, Hyungsoon Im, Xiaofeng Yao, Sang-Hyun Oh, Jian-Ping Wang

Department of Electrical and Computer Engineering,  University of Minnesota, Minneapolis, MN, 55455, USADepartment of Chemical Engineering and Materials Science,  University of Minnesota, Minneapolis, MN, 55455, USA

Marlene Castro, Wei-Shou Hu

Department of Electrical and Computer Engineering,  University of Minnesota, Minneapolis, MN, 55455, USADepartment of Chemical Engineering and Materials Science,  University of Minnesota, Minneapolis, MN, 55455, USA

J. Med. Devices 2(2), 027529 (Jun 12, 2008) (1 page) doi:10.1115/1.2936202 History: Published June 12, 2008

Abstract

Current methods for pathogen detection require days before a result is available, while biosensors offer the advantage of quick, on the spot results. In this project we present the proof of concept of a biosensor that uses giant magnetoresistance (GMR) sensors and a microfluidic system. The bioprobe consists of a 30 bp oligonucleotide, 5 functionalized with a thiol group (T-DNA30) immobilized on a gold surface. Hybridization was tested with a 5-biotinylated oligonucleotide complementary to T-DNA30 to which Streptavidin-R-Phycoerythrin was attached later. The difference in fluorescence between the target sample and control samples was observed using a scanning laser confocal fluorescence microscope. The GMR device consists of an Ir0.8Mn0.2Co0.9Fe0.1CuCo0.9Fe0.1Ni0.82Fe0.12 multilayer structure. Magnetic nanoparticles were deposited directly on the surface of the GMR sensors. An external magnetic field was employed to polarize the nanoparticles, which can then be detected by comparing the resistance change loops of the GMR sensors before and after their deposition. A transparent elastomer, polydimethylsiloxane (PDMS), was used for the microfluidic system. The system comprises two microfluidic channels separated by a 200μm PDMS wall. The channel width is 200μm and its height 100μm. The PDMS channel was permanently bonded to the SiO2 surface of the GMR sensor. The integrated biosensor will immobilize thiolated DNA on the gold surface below which the GMR device is located. For hybridization, biotinylated DNA will be used. Finally, magnetic nanoparticles, coated with streptavidin will be attached to the hybridized DNA and detected by the GMR device.

Copyright © 2008 by American Society of Mechanical Engineers
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