Nano Archive

Multiparameter magnetic relaxation switch assays

Taktak, Sonia and Sosnovik, David and Cima, Michael J. and Weissfeder, Ralph and Josephson, Lee (2007) Multiparameter magnetic relaxation switch assays. ANALYTICAL CHEMISTRY, 79 (23). pp. 8863-8869.

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Official URL: http://dx.doi.org/10.1021/ac701976p

Abstract

Magnetic nanoparticles (NPs) can serve as magnetic relaxation switches (MRSVs), switching from a dispersed to a clustered state, or the reverse, due to the presence of molecular targets, with changes in the spin-spin relaxation time of water (T-2). Biotinylated NP probes reacted with an avidin molecular target to form stable NP clusters, which permitted several NMR parameters to be measured as a function of cluster size. Associated with avidin-induced NP cluster formation was an increase in the spin-spin relation rate (1/T-2), while the spin-lattice relaxation rate (1/T-1)was unaffected. On the basis of the selective effects of NP cluster formation on T-2, we developed a T-1/T-2 interrogation method where NP probe concentration and avidin analyte were unknown and both were determined. A third NMR parameter examined was the replication of T-2 measurements, which were used to rapidly determine whether the ratio of avidin to biotinylated NP was optimal or whether additional biotinylated NP was needed. The T-1/T-2 and T-2 replication interrogation methods illustrate how MRSw assays can employ multiple parameters, instead of relying only on T-2, to obtain information about the reaction of NPs with molecular targets.

Item Type:Article
Subjects:Physical Science > Nanomagnetics
Material Science > Nanostructured materials
Material Science > Nanochemistry
ID Code:1160
Deposited By:Anuj Seth
Deposited On:17 Dec 2008 10:17
Last Modified:17 Dec 2008 10:17

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