Intrinsic peroxidase-like activity of ferromagnetic nanoparticles

The work built off a seminal finding by Gao and colleagues, published in 2007 in Nature Nanotechnology, showing that nanoparticles, long believed to be biologically and chemically inert, could in fact possess enzyme-like properties. In that study, Gao showed that an iron oxide nanoparticle behaved similarly to a peroxidase, an enzyme found naturally that catalyzes oxidative reactions, often using hydrogen peroxide.

ArticleNature Nanotechnology 2, 577 - 583 (2007) 
Published online: 26 August 2007 | doi:10.1038/nnano.2007.260

Intrinsic peroxidase-like activity of ferromagnetic nanoparticles

Lizeng Gao 1, 2, 3, 6, Jie Zhuang 1, 2, 3, 6, Leng Nie 3, 4, Jinbin Zhang 1, 2, 3, Yu Zhang 5, Ning Gu 5, Taihong Wang 4, Jing Feng 1, 2, Dongling Yang 1, 2, Sarah Perrett 1 & Xiyun Yan 1, 2

Abstract
Nanoparticles containing magnetic materials, such as magnetite (Fe3O4), are particularly useful for imaging and separation techniques. As these nanoparticles are generally considered to be biologically and chemically inert, they are typically coated with metal catalysts, antibodies or enzymes to increase their functionality as separation agents. Here, we report that magnetite nanoparticles in fact possess an intrinsic enzyme mimetic activity similar to that found in natural peroxidases, which are widely used to oxidize organic substrates in the treatment of wastewater or as detection tools. Based on this finding, we have developed a novel immunoassay in which antibody-modified magnetite nanoparticles provide three functions: capture, separation and detection. The stability, ease of production and versatility of these nanoparticles makes them a powerful tool for a wide range of potential applications in medicine, biotechnology and environmental chemistry.

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