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Title: 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. In conclusion, the AuNC displays phosphorescence with large Stokes shift and microsecond lifetime.
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [2] ;  [1] ;  [2] ;  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. The Univ. of New Mexico, Albuquerque, NM (United States)
Publication Date:
OSTI Identifier:
1227636
Report Number(s):
LA-UR--15-23188
Journal ID: ISSN 0002-7863
Grant/Contract Number:
FA9550-12-1-0112; W911NF-14-1-0263; AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 137; Journal Issue: 36; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society (ACS)
Research Org:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; 36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY