Effect of Ligand Charge on Electron-Transfer Rates of Water-Soluble Gold Nanoparticles

2015 ◽  
Vol 119 (21) ◽  
pp. 11296-11300 ◽  
Author(s):  
David Crisostomo ◽  
Rachel R. Greene ◽  
David E. Cliffel
Keyword(s):  
Gold Nanoparticles ◽  
Electron Transfer ◽  
Water Soluble ◽  
Transfer Rates

scholarly journals Cryo-EM structure and kinetics reveal electron transfer by 2D diffusion of cytochrome c in the yeast III-IV respiratory supercomplex

2021 ◽  
Vol 118 (11) ◽  
pp. e2021157118
Author(s):  
Agnes Moe ◽  
Justin Di Trani ◽  
John L. Rubinstein ◽  
Peter Brzezinski
Keyword(s):  
Electron Transfer ◽  
Respiratory Chain ◽  
Water Soluble ◽  
Three Dimensions ◽  
Oxidoreductase Activity ◽  
Transfer Rates ◽  
Cellular Processes ◽  
Membrane Bound ◽  
Kinetics Of ◽  
Positively Charged

Energy conversion in aerobic organisms involves an electron current from low-potential donors, such as NADH and succinate, to dioxygen through the membrane-bound respiratory chain. Electron transfer is coupled to transmembrane proton transport, which maintains the electrochemical proton gradient used to produce ATP and drive other cellular processes. Electrons are transferred from respiratory complexes III to IV (CIII and CIV) by water-soluble cytochrome (cyt.) c. In Saccharomyces cerevisiae and some other organisms, these complexes assemble into larger CIII2CIV1/2 supercomplexes, the functional significance of which has remained enigmatic. In this work, we measured the kinetics of the S. cerevisiae supercomplex cyt. c-mediated QH2:O2 oxidoreductase activity under various conditions. The data indicate that the electronic link between CIII and CIV is confined to the surface of the supercomplex. Single-particle electron cryomicroscopy (cryo-EM) structures of the supercomplex with cyt. c show the positively charged cyt. c bound to either CIII or CIV or along a continuum of intermediate positions. Collectively, the structural and kinetic data indicate that cyt. c travels along a negatively charged patch on the supercomplex surface. Thus, rather than enhancing electron transfer rates by decreasing the distance that cyt. c must diffuse in three dimensions, formation of the CIII2CIV1/2 supercomplex facilitates electron transfer by two-dimensional (2D) diffusion of cyt. c. This mechanism enables the CIII2CIV1/2 supercomplex to increase QH2:O2 oxidoreductase activity and suggests a possible regulatory role for supercomplex formation in the respiratory chain.

Quantification of electron transfer rates of different facets on single gold nanoparticles during catalytic reactions

2013 ◽  
Vol 49 (45) ◽  
pp. 5204 ◽  
Author(s):  
Moonjung Eo ◽  
Jayeon Baek ◽  
Hyeon Don Song ◽  
Suseung Lee ◽  
Jongheop Yi
Keyword(s):  
Gold Nanoparticles ◽  
Electron Transfer ◽  
Catalytic Reactions ◽  
Transfer Rates

Photochemical reactions in organized assemblies. 40. Amylose and carboxymethylamylose inclusion complexes with photoreactive molecules

1985 ◽  
Vol 63 (6) ◽  
pp. 1315-1319 ◽  
Author(s):  
Brian R. Suddaby ◽  
Raymond N. Dominey ◽  
Y. Hui ◽  
David G. Whitten
Keyword(s):  
Electron Transfer ◽  
Photochemical Reactions ◽  
Water Soluble ◽  
Enhanced Fluorescence ◽  
Transfer Rates ◽  
Back Electron Transfer ◽  
Organized Assemblies ◽  
Stilbene Derivatives ◽  
Polypyridine Complexes ◽  
Ruthenium Polypyridine

This paper focuses on a study of unimolecular and bimolecular photoreactions occurring with reactants which can be incorporated into the linear polysugars amylose and carboxymethylamylose. Hydrophobic and surfactant trans (E) stilbene derivatives form complexes in which the stilbene chromophore shows enhanced fluorescence and reduced trans → cis isomerization efficiencies. The reactivity of the excited surfactant–stilbene singlet towards the quencher iodide ion has been compared in water/dimethylsulfoxide in the presence and absence of amylose under conditions where complex formation is nearly complete. Some relatively hydrophobic viologen dications have also been found to form complexes with the water soluble carboxymethylamylose. Although the dications complex relatively weakly, the partially reduced monocations complex more strongly. This results in selective retardation of back electron transfer rates when the viologens are used as electron transfer quencher-oxidants for certain luminescent ruthenium polypyridine complexes.

Molecularly Imprinted Sensor for Ascorbic Acid Based on Gold Nanoparticles and Multiwalled Carbon Nanotubes

2020 ◽  
Vol 16 (7) ◽  
pp. 905-913
Author(s):  
Youyuan Peng ◽  
Qingshan Miao
Keyword(s):  
Carbon Nanotubes ◽  
Gold Nanoparticles ◽  
Ascorbic Acid ◽  
Multiwalled Carbon Nanotubes ◽  
Ph Value ◽  
Biological Fluids ◽  
Water Soluble ◽  
Multiwalled Carbon ◽  
Experimental Conditions ◽  
Molecularly Imprinted

Background: L-Ascorbic acid (AA) is a kind of water soluble vitamin, which is mainly present in fruits, vegetables and biological fluids. As a low cost antioxidant and effective scavenger of free radicals, AA may help to prevent diseases such as cancer and Parkinson’s disease. Owing to its role in the biological metabolism, AA has also been utilized for the therapy of mental illness, common cold and for improving the immunity. Therefore, it is very necessary and urgent to develop a simple, rapid and selective strategy for the detection of AA in various samples. Methods: The molecularly imprinted poly(o-phenylenediamine) (PoPD) film was prepared for the analysis of L-ascorbic acid (AA) on gold nanoparticles (AuNPs) - multiwalled carbon nanotubes (MWCNTs) modified glass carbon electrode (GCE) by electropolymerization of o-phenylenediamine (oPD) and AA. Experimental parameters including pH value of running buffer and scan rates were optimized. Scanning electron microscope (SEM), fourier-transform infrared (FTIR) spectra, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were utilized for the characterization of the imprinted polymer film. Results: Under the selected experimental conditions, the DPV peak currents of AA exhibit two distinct linear responses ranging from 0.01 to 2 μmol L-1 and 2 to 100 μmol L-1 towards the concentrations of AA, and the detection limit was 2 nmol L-1 (S/N=3). Conclusion: The proposed electrochemical sensor possesses excellent selectivity for AA, along with good reproducibility and stability. The results obtained from the analysis of AA in real samples demonstrated the applicability of the proposed sensor to practical analysis.

Quantification of Electron Transfer Rates to a Solid Phase Electron Acceptor through the Stages of Biofilm Formation from Single Cells to Multicellular Communities

2010 ◽  
Vol 44 (7) ◽  
pp. 2721-2727 ◽  
Author(s):  
Jeffrey S. McLean ◽  
Greg Wanger ◽  
Yuri A. Gorby ◽  
Martin Wainstein ◽  
Jeff McQuaid ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Electron Acceptor ◽  
Biofilm Formation ◽  
Solid Phase ◽  
Single Cells ◽  
Transfer Rates

Synthesis and Characterization of Water-Soluble Monolayer-Protected Gold Nanoparticles

2011 ◽  
Vol 415-417 ◽  
pp. 617-620 ◽  
Author(s):  
Yan Su ◽  
Ying Yun Lin ◽  
Yu Li Fu ◽  
Fan Qian ◽  
Xiu Pei Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Gold Nanoparticles ◽  
Average Particle Size ◽  
Water Soluble ◽  
Synthesis And Characterization ◽  
Average Particle ◽  
Transmission Electron

Water-soluble gold nanoparticles (AuNPs) were prepared using 2-mercapto-4-methyl-5- thiazoleacetic acid (MMTA) as a stabilizing agent and sodium borohydride (NaBH4) as a reducing agent. The AuNPs product was analyzed by transmission electron microscopy (TEM), UV-vis absorption spectroscopy and Fourier transform infrared spectroscopy (FTIR). The TEM image shows that the particles were well-dispersed and their average particle size is about 5 nm. The UV-vis absorption and FTIR spectra confirm that the MMTA-AuNPs was stabilized by the carboxylate ions present on the surface of the AuNPs.

scholarly journals Water-soluble low-molecular-weight cellulose chains radially oriented on gold nanoparticles

Cellulose ◽  
2011 ◽  
Vol 18 (4) ◽  
pp. 929-936 ◽  
Author(s):  
Yukiko Enomoto-Rogers ◽  
Hiroshi Kamitakahara ◽  
Arata Yoshinaga ◽  
Toshiyuki Takano
Keyword(s):  
Molecular Weight ◽  
Gold Nanoparticles ◽  
Water Soluble ◽  
Low Molecular Weight
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