Intrinsic peroxidase-like activity of ferromagnetic nanoparticles

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.

TiO2@CeOx Core–Shell Nanoparticles as Artificial Enzymes with Peroxidase-Like Activity

“…In general, nanozymes require a higher peroxide concentration than HRP to reach the maximum activity. 34,35,38 Interestingly, our core-shell NPs escape this trend.…”

“…The results (double reciprocal plots) are shown in Figure S4 Table 1), but lower with respect to HRP (0.43 mM), 34 denoting a good affinity for TMB, which is a common feature of all inorganic mimics of peroxidase, such as Fe 3 O 4 , 34 CuO, 35 and FeS. 36,37 On the contrary, the affinity towards the oxidant is much scarcer.…”

Assessing nanoparticle toxicity in cell-based assays: influence of cell culture parameters and optimized models for bridging the in vitro–in vivo gap

“…observed an intrinsic peroxidase-like activity for unimpaired IONP in a cell free environment and Huang et al saw the same effect in mesenchymal stem cells, , where IONPs were found to promote cell proliferation 53,54 . Unlike for ROS induction the mechanism behind this protective effect has not yet been unravelled.…”

Fe3O4 Magnetic Nanoparticle Peroxidase Mimetic-Based Colorimetric Assay for the Rapid Detection of Organophosphorus Pesticide and Nerve Agent

“…11,12 In previous studies, we first reported that Fe 3 O 4 MNPs exhibit peroxidase activity that can catalyze the oxidation of peroxidase substrates in the presence of H 2 O 2 to produce a color reaction. 18 Since reported in 2007, the novel catalytic property of MNPs has been widely used for laboratory tests, biomedical detection, and environmental analysis. 19 23 Briefly, FeCl 3 ·6H 2 O (0.6 g) was dissolved in 20 mL of ethylene glycol followed by addition of 1.5 g of sodium acetate.…”

“…18 Although this acidic solution is not normally used for the AChE and CHO catalyzed H 2 O 2 generation reaction, the pH 5.0 acetate buffered assay solution permitted the achievement of enough color intensity from the MNP-catalyzed color reaction to carry on the OP neurotoxin inhibition reaction (Figure 1 left). The results suggest that, even at the acidic pH, the activity of enzymes AChE and CHO is high enough to generate sufficient H 2 O 2 for the MNP-catalyzed color reaction.…”