Patchy gold coated Fe<inf>3</inf>O<inf>4</inf>nanospheres with enhanced catalytic activity applied for paper-based bipolar electrode-electrochemiluminescence aptasensors

Key Words:Sulfur compounds;Antigens - Catalyst activity - Electrodes - Electrolytic reduction - Gold coatings - Gold compounds - Hydrogen peroxide - Iron oxides - Magnetite - Oxidation - Peroxides - Rate constants - Synthesis (chemical);Bipolar electrodes - Carcinoembryonic antigen - Electrochemical reductions - Electrochemiluminescence - Enhanced catalytic activity - Fe3O4 - Michaelis-Menten constant - Morphological evolution

Abstract:In this work, novel multifunctional patchy gold coated Fe<inf>3</inf>O<inf>4</inf>hybrid nanoparticles (PG-Fe<inf>3</inf>O<inf>4</inf>NPs) have been successfully synthesized in aqueous medium via a facile adsorption-reduction method. A rational formation mechanism has been proposed by monitoring the morphological evolution. The PG-Fe<inf>3</inf>O<inf>4</inf>NPs retained the good magnetic property and exhibited excellent catalytical effeciency towards the electrochemical reduction of hydrogen peroxide. Chronoamperometric and amperometric experiments indicated a relatively high catalytic rate constant of 3.13 &times; 10⁵M^&minus;1s^&minus;1, a high sensitivity of 578.87 &micro;A mM^&minus;1cm^&minus;2and a low Michaelis-Menten constant of 462 &micro;M. Meanwhile, the introduction of patchy gold could help biofunctionalization via Au-S bond for different biodetection and biosensing purposes. Here, as an example, thiol-terminated aptamers were immobilized onto the patchy gold part as a signal probe to detect carcinoembryonic antigen (CEA). A related paper-based bipolar electrode-electrochemiluminescence (pBPE-ECL) aptasensor was fabricated as the low-cost, disposable and miniature platform. To improve the sensitivity, Au nanodendrites were electrodeposited at the BPE cathode as the matrix for Apt1 immobilization. This aptasensor showed a wide linear range of 0.1 pg mL^&minus;1&ndash;15 ng mL^&minus;1with a low detection limit of 0.03 pg mL^&minus;1, remaining competitive against other ones, and also demonstrating the PG-Fe<inf>3</inf>O<inf>4</inf>NPs have promising potential for catalysis and bioassays.<br/> &copy; 2018 Elsevier B.V.

Volume:114

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Translation or Not:no