A Hybrid DNA-Templated Gold Nanocluster For Enhanced Enzymatic Reduction of Oxygen.
We report the synthesis and characterization of a new DNA-templated gold nanocluster (AuNC) of ∼1 nm in diameter and possessing ∼7 Au atoms. When integrated with bilirubin oxidase (BOD) and single walled carbon nanotubes (SWNTs), the AuNC acts as an enhancer of electron transfer (ET) and lowers the overpotential of electrocatalytic oxygen reduction reaction (ORR) by ∼15 mV as compared to the enzyme alone. In addition, the presence of AuNC causes significant enhancements in the electrocatalytic current densities at the electrode. Control experiments show that such enhancement of ORR by the AuNC is specific to nanoclusters and not to plasmonic gold particles. Rotating ring disk electrode (RRDE) measurements confirm 4e(-) reduction of O2 to H2O with minimal production of H2O2, suggesting that the presence of AuNC does not perturb the mechanism of ORR catalyzed by the enzyme. This unique role of the AuNC as enhancer of ET at the enzyme-electrode interface makes it a potential candidate for the development of cathodes in enzymatic fuel cells, which often suffer from poor electronic communication between the electrode surface and the enzyme active site. Finally, the AuNC displays phosphorescence with large Stokes shift and microsecond lifetime.
Saumen
S
Chakraborty
Center for Micro-Engineered Materials (CMEM) and Department of Chemical & Biological Engineering, The University of New Mexico, Advanced Materials Laboratory , 1001 University Blvd. SE, Albuquerque, New Mexico 87106, United States.
Sofia
S
Babanova
Reginaldo C
RC
Rocha
Anil
A
Desireddy
Center for Micro-Engineered Materials (CMEM) and Department of Chemical & Biological Engineering, The University of New Mexico, Advanced Materials Laboratory , 1001 University Blvd. SE, Albuquerque, New Mexico 87106, United States.
Kateryna
K
Artyushkova
Amy E
AE
Boncella
Center for Micro-Engineered Materials (CMEM) and Department of Chemical & Biological Engineering, The University of New Mexico, Advanced Materials Laboratory , 1001 University Blvd. SE, Albuquerque, New Mexico 87106, United States.
Plamen
P
Atanassov
Jennifer S
JS
Martinez
D004247:DNA / Q000737:chemistry*; D004798:Enzymes / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D010100:Oxygen / Q000737:chemistry*
D004798:Enzymes; D006046:Gold; D004247:DNA; D010100:Oxygen