A Detection System Based on Giant Magnetoresistive Sensors and High-Moment Magnetic Nanoparticles Demonstrates Zeptomole Sensitivity: Potential for Personalized Medicine

This paper presents a novel architecture for a bio-detection system to reuse magnetoresistive sensors and improve its repeatability. The architecture is composed of two fixed magnetoresistive sensors, a movable biochip, a microfluidic device and two current straps. On the action of a magnetic field gradient generated by current strap, functional magnetic particles pass along the channel. Some particles are bound by a special reaction to the biochip surface, and magnetoresistive sensors on the two ends measure the number of particles of original state and subsequencial state. The signal difference of two magnetoresistive sensors reflect the number of the depletion magnetic particles captured by the biochip.

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Design and fabrication of non-superparamagnetic high moment magnetic nanoparticles for bioapplications

Journal of Nanoparticle Research ◽

10.1007/s11051-009-9761-4 ◽

2009 ◽

Vol 12 (4) ◽

pp. 1101-1106 ◽

Cited By ~ 5

Author(s):

Punnapob Punnakitikashem ◽

Shih-Hsin Chang ◽

Chien-Wen Huang ◽

J. Ping Liu ◽

Yaowu Hao

Keyword(s):

Magnetic Nanoparticles ◽

High Moment

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Colorimetric Detection System forSalmonella typhimuriumBased on Peroxidase-Like Activity of Magnetic Nanoparticles with DNA Aptamers

Journal of Nanomaterials ◽

10.1155/2015/527126 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 14

Author(s):

Ji Young Park ◽

Ha Young Jeong ◽

Moon Il Kim ◽

Tae Jung Park

Keyword(s):

Catalytic Activity ◽

Magnetic Nanoparticles ◽

Peroxidase Activity ◽

Detection System ◽

Low Cost ◽

Colorimetric Detection ◽

Food Poisoning ◽

Health Issues ◽

Color Changes ◽

Detection Systems

Recently, much attention has been devoted to food-related health issues. In particular, food-poisoning bacteria are becoming a serious threat to human health. So far, techniques used to detect these bacteria are time-consuming and laborious. To overcome these challenges, a biosensor with a simple platform was developed to detectSalmonella typhimurium. The colorimetric strategy is attractive because it enables simple and rapid sensing with the naked eyes. We used magnetic nanoparticles (MNPs), specific aptamers, and a colorimetric substrate, 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H2O2. Because MNPs display enzyme-like activities, they can undergo color changes with the help of a colorimetric substrate. In this system, MNPs were first incubated with aptamers that specifically interact with theSalmonellaspecies, reducing the peroxidase activity of the MNPs via DNA-mediated shielding of catalytic activity. After the addition ofSalmonellacells to the solution, specific aptamers on the MNPs interact with theSalmonella, consequently enhancing the peroxidase activity of the MNPs. Considering their low cost, easy separation, and stable activity, MNPs could be applied to various detection systems.

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