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Biomolecular interactions detected magnetically
Highly uniform nanoparticles with magnetic iron oxide cores can be attached covalently to oligonucleotides, proteins, and small organic molecules and then used to detect interactions among such species in functional genomics and proteomics studies. find that the nanoparticles act as "magnetic relaxation switches" by changing the relaxation state of protons in surrounding water molecules. This effect can be picked up by nuclear magnetic resonance or magnetic resonance imaging instruments, making it possible to detect interactions among molecules to which the nanoparticles are attached. The researchers show that the method can detect DNA, mRNA, and protein interactions, as well as protease activity, in a high-throughput array format and with high sensitivity. The iron oxide crystals they use are nontoxic and are already in routine clinical use, so in vivo imaging applications may be possible, they say.
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