Detection of Bacteria in Suspension Using a Superconducting Quantum Interference Device

Grossman, H. L. ; Myers, W. R. ; Vreeland, V. J. ; Bruehl, R. ; Alper, M. D.

Technical Information Center Oak Ridge Tennessee

关键词: Biological detection;    Bacteria;    Magnetic fields;    Particles;    Assaying;   

RP-ID  :  DE2005836039

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

We demonstrate a technique for detecting magnetically-labeled Listeria monocytogenes and for measuring the binding rate between antibody-linked magnetic particles and bacteria. This assay, which is both sensitive and straightforward to perform, can quantify specific bacteria in a sample without the need to immobilize the bacteria or wash away unbound magnetic particles. In the measurement, we add 50 nm diameter superparamagnetic particles, coated with antibodies, to a liquid sample containing L. monocytogenes. We apply a pulsed magnetic field to align the magnetic dipole moments and use a high transition temperature Superconducting Quantum Interference Device (SQUID), an extremely sensitive detector of magnetic flux, to measure the magnetic relaxation signal when the field is turned off.