A Biosensor Based on Magnetic Resonance Relaxation

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1264721 - ProrokConventional culture and susceptibility tests continue to remain the ?gold standard? for identifying pathogens in clinical and other settings. Many new pathogen detection approaches have aimed at replacing this standard by providing more rapid, more accurate and less expensive detection. Very promising techniques such as PCR, surface enhanced Raman, and others have proven adept at pathogen detection, but end users have not warmed up to their expense, extensive sample preparation and skill set necessary to perform them. The field continues to search for a rapid, sensitive, and specific detection technology that is cost-effective and easy to use. The proposed work aims to develop such a biosensor based on magnetic resonance relaxation switching. The method leverages a large body of work involving nanoscale contrast agents employed in nuclear magnetic resonance (NMR) imaging. The aim here is to develop a detection approach that mimics the human immune response to an invading pathogen, the release of 109 to 1012 specific antigens to guarantee quick contact with the pathogen. This proposed technique will employ magnetic nanoparticle contrast agents conjugated with specific capture agents to achieve a similar contact goal. Detection of the species will involve monitoring the average relaxation time (T2) of water protons in the solution, which is highly sensitive to the concentration and distribution of the magnetic nanoparticles present. With multiple nanoparticles attaching to each individual target species their distribution will be altered, and correspondingly, the average proton relaxation time will change. Although, this method leverages well established principles of NMR imaging, this measurement can be accomplished with a simple hand-held relaxometer. Content in layman?s termsThis proposal will develop new ways to detect bacteria and other pathogens in food or bodily fluids. This technology will use magnetic particles whose magnetic properties will change in predictable ways upon binding of bacteria. The authors envision being able to detect multiple bacteria using sets of unique magnetic nanoparticles.