title: Amplified Peroxidase-Like Activity in Iron Oxide Nanoparticles Using Adenosine Monophosphate: Application to Urinary Protein Sensing.
abstract: Numerous compounds such as protein and double-stranded DNA have been shown to efficiently inhibit intrinsic peroxidase-mimic activity in Fe3O4nanoparticles (NP) and other related nanomaterials. However, only a few studies have focused on finding new compounds for enhancing the catalytic activity of Fe3O4NP-related nanomaterials. Herein, phosphate containing adenosine analogs are reported to enhance the oxidation reaction of hydrogen peroxide (H2O2) and amplex ultrared (AU) for improving the peroxidase-like activity in Fe3O4NPs. This enhancement is suggested to be a result of the binding of adenosine analogs to Fe2+/Fe3+sites on the NP surface and from adenosine 5'-monophosphate (AMP) acting as the distal histidine residue of horseradish peroxidase for activating H2O2. Phosphate containing adenosine analogs revealed the following trend for the enhanced activity of Fe3O4NPs: AMP > adenosine 5'-diphosphate > adenosine 5'-triphosphate. The peroxidase-like activity in the Fe3O4NPs progressively increased with increasing AMP concentration and polyadenosine length. The Michaelis constant for AMP attached Fe3O4NPs is 5.3-fold lower and the maximum velocity is 2.7-fold higher than those of the bare Fe3O4NPs. Furthermore, on the basis of AMP promoted peroxidase mimicking activity in the Fe3O4NPs and the adsorption of protein on the NP surface, a selective fluorescent turn-off system for the detection of urinary protein is developed.
authors.affiliation: Department of Chemistry, National Sun Yat-sen University , Taiwan.
authors.forename: Ya-Chun
authors.initials: YC
authors.lastname: Yang
authors.affiliation: Department of Chemistry, National Sun Yat-sen University , Taiwan.
authors.forename: Yen-Ting
authors.initials: YT
authors.lastname: Wang
authors.affiliation: Department of Chemistry, National Sun Yat-sen University , Taiwan.|School of Pharmacy, College of Pharmacy, Kaohsiung Medical University , Taiwan.|Center for Nanoscience and Nanotechnology, National Sun Yat-sen University , Taiwan.
authors.forename: Wei-Lung
authors.identifier: http://orcid.org/0000-0001-9808-5863
authors.initials: WL
authors.lastname: Tseng
mesh_terms: D000249:Adenosine Monophosphate; D005290:Ferric Compounds; D006861:Hydrogen Peroxide; D053768:Metal Nanoparticles
chemical_list: D005290:Ferric Compounds; C000499:ferric oxide; D000249:Adenosine Monophosphate; D006861:Hydrogen Peroxide
keywords: adenosine monophosphate; amplex ultrared; human serum albumin; iron oxide nanoparticles; peroxidase mimic