Abstract
We report a fluorescence approach for the highly selective and sensitive detection of catecholamines using magnetite nanoparticles (Fe3O4 NPs) in the presence of Amplex UltraRed (AUR) and H2O2. Fe3O4 NPs catalyze H2O2-mediated oxidation of AUR. The resulting product fluoresces (excitation/emission maxima, ca. 568/587nm) more strongly, relative to AUR. When catecholamines bind to Fe3O4, the complexes that are formed induce decreased activity of Fe3O4 NPs, mediated through the coordination between Fe3+ on the NP surface and the catechol moiety of catecholamines. As a result, Fe3O4 NPs-catalyzed H2O2-mediated oxidation of AUR is inhibited by catecholamines. The limits of detection for dopamine (DA), l-DOPA, norepinephrine, and epinephrine were 3nM, 3nM, 3nM, and 6nM, respectively. The Fe3O4 NPs-H2O2-AUR probe exhibited high selectivity (>1000-fold) toward catecholamines over other tested biomolecules that commonly exist in urine. Four catecholamines had similar sensitivity because the inhibition of the Fe3O4 NPs activity relies on the presence of the catechol moiety. This approach also allowed the determination of tyrosinase activity because tyrosinase catalyzes the conversion of l-tyrosine to l-DOPA. We validated the practicality of the use of the Fe3O4 NPs-H2O2-AUR probe for the determination of the concentrations of DA in urine samples.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
