Limits...
A Decaheme Cytochrome as a Molecular Electron Conduit in Dye-Sensitized Photoanodes.

Hwang ET, Sheikh K, Orchard KL, Hojo D, Radu V, Lee CY, Ainsworth E, Lockwood C, Gross MA, Adschiri T, Reisner E, Butt JN, Jeuken LJ - Adv Funct Mater (2015)

Bottom Line: The system is assembled by forming a densely packed MtrC film on an ultra-flat gold electrode, followed by the adsorption of approximately 7 nm TiO2 nanocrystals that are modified with a phosphonated bipyridine Ru(II) dye (RuP).The step-by-step construction of the MtrC/TiO2 system is monitored with (photo)electrochemistry, quartz-crystal microbalance with dissipation (QCM-D), and atomic force microscopy (AFM).Photocurrents are dependent on the redox state of the MtrC, confirming that electrons are transferred from the TiO2 nanocrystals to the surface via the MtrC conduit.

View Article: PubMed Central - PubMed

Affiliation: School of Biomedical Sciences, University of Leeds Leeds, LS2 9JT, UK E-mail: L.J.C.Jeuken@leeds.ac.uk ; The Astbury Centre for Structural Molecular Biology, University of Leeds Leeds, LS2 9JT, UK.

ABSTRACT

In nature, charge recombination in light-harvesting reaction centers is minimized by efficient charge separation. Here, it is aimed to mimic this by coupling dye-sensitized TiO2 nanocrystals to a decaheme protein, MtrC from Shewanella oneidensis MR-1, where the 10 hemes of MtrC form a ≈7-nm-long molecular wire between the TiO2 and the underlying electrode. The system is assembled by forming a densely packed MtrC film on an ultra-flat gold electrode, followed by the adsorption of approximately 7 nm TiO2 nanocrystals that are modified with a phosphonated bipyridine Ru(II) dye (RuP). The step-by-step construction of the MtrC/TiO2 system is monitored with (photo)electrochemistry, quartz-crystal microbalance with dissipation (QCM-D), and atomic force microscopy (AFM). Photocurrents are dependent on the redox state of the MtrC, confirming that electrons are transferred from the TiO2 nanocrystals to the surface via the MtrC conduit. In other words, in these TiO2/MtrC hybrid photodiodes, MtrC traps the conduction-band electrons from TiO2 before transferring them to the electrode, creating a photobioelectrochemical system in which a redox protein is used to mimic the efficient charge separation found in biological photosystems.

No MeSH data available.


Related in: MedlinePlus

Left: Schematic representation of the layered MtrC/TiO2 system on a SAM-modified gold electrode and the interfacial electron-transfer steps required for the generation of a ­photocurrent. Right: The molecular structure of the cation Ru(bpy)2(4,4'-(PO3H2)2bpy)2+ (RuP).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4493899&req=5

fig01: Left: Schematic representation of the layered MtrC/TiO2 system on a SAM-modified gold electrode and the interfacial electron-transfer steps required for the generation of a ­photocurrent. Right: The molecular structure of the cation Ru(bpy)2(4,4'-(PO3H2)2bpy)2+ (RuP).

Mentions: Besides using biosystems for light harvesting, many studies have been performed with inorganic systems such as semiconducting nanoparticles or quantum dots.[21,22] Although inorganic materials do not suffer the generally short lifespan of their biological counterparts, they often suffer in their quantum yield as they are not as efficient in charge separation. In biology, charge separation proceeds by a series of fast electron-transfer steps along a chain or wire of redox centers. Here, we report on a hybrid system where we have coupled a dye-sensitized TiO2 nanocrystal to a decaheme protein from Shewanella oneidensis MR-1, known as MtrC (Figure1). In this biomimetic system, the dye-sensitized nanocrystal functions as the light-harvesting center and MtrC provides a long redox chain for charge separation. Electron transfer across the 10 hemes in MtrC will spatially separate the photoinduced charge from the nanocrystal, potentially reducing charge recombination. The successful construction of the biohybrid system is confirmed by a ­photoswitching behavior where the photocurrent depends on the redox state of the MtrC electrical bridge.


A Decaheme Cytochrome as a Molecular Electron Conduit in Dye-Sensitized Photoanodes.

Hwang ET, Sheikh K, Orchard KL, Hojo D, Radu V, Lee CY, Ainsworth E, Lockwood C, Gross MA, Adschiri T, Reisner E, Butt JN, Jeuken LJ - Adv Funct Mater (2015)

Left: Schematic representation of the layered MtrC/TiO2 system on a SAM-modified gold electrode and the interfacial electron-transfer steps required for the generation of a ­photocurrent. Right: The molecular structure of the cation Ru(bpy)2(4,4'-(PO3H2)2bpy)2+ (RuP).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493899&req=5

fig01: Left: Schematic representation of the layered MtrC/TiO2 system on a SAM-modified gold electrode and the interfacial electron-transfer steps required for the generation of a ­photocurrent. Right: The molecular structure of the cation Ru(bpy)2(4,4'-(PO3H2)2bpy)2+ (RuP).
Mentions: Besides using biosystems for light harvesting, many studies have been performed with inorganic systems such as semiconducting nanoparticles or quantum dots.[21,22] Although inorganic materials do not suffer the generally short lifespan of their biological counterparts, they often suffer in their quantum yield as they are not as efficient in charge separation. In biology, charge separation proceeds by a series of fast electron-transfer steps along a chain or wire of redox centers. Here, we report on a hybrid system where we have coupled a dye-sensitized TiO2 nanocrystal to a decaheme protein from Shewanella oneidensis MR-1, known as MtrC (Figure1). In this biomimetic system, the dye-sensitized nanocrystal functions as the light-harvesting center and MtrC provides a long redox chain for charge separation. Electron transfer across the 10 hemes in MtrC will spatially separate the photoinduced charge from the nanocrystal, potentially reducing charge recombination. The successful construction of the biohybrid system is confirmed by a ­photoswitching behavior where the photocurrent depends on the redox state of the MtrC electrical bridge.

Bottom Line: The system is assembled by forming a densely packed MtrC film on an ultra-flat gold electrode, followed by the adsorption of approximately 7 nm TiO2 nanocrystals that are modified with a phosphonated bipyridine Ru(II) dye (RuP).The step-by-step construction of the MtrC/TiO2 system is monitored with (photo)electrochemistry, quartz-crystal microbalance with dissipation (QCM-D), and atomic force microscopy (AFM).Photocurrents are dependent on the redox state of the MtrC, confirming that electrons are transferred from the TiO2 nanocrystals to the surface via the MtrC conduit.

View Article: PubMed Central - PubMed

Affiliation: School of Biomedical Sciences, University of Leeds Leeds, LS2 9JT, UK E-mail: L.J.C.Jeuken@leeds.ac.uk ; The Astbury Centre for Structural Molecular Biology, University of Leeds Leeds, LS2 9JT, UK.

ABSTRACT

In nature, charge recombination in light-harvesting reaction centers is minimized by efficient charge separation. Here, it is aimed to mimic this by coupling dye-sensitized TiO2 nanocrystals to a decaheme protein, MtrC from Shewanella oneidensis MR-1, where the 10 hemes of MtrC form a ≈7-nm-long molecular wire between the TiO2 and the underlying electrode. The system is assembled by forming a densely packed MtrC film on an ultra-flat gold electrode, followed by the adsorption of approximately 7 nm TiO2 nanocrystals that are modified with a phosphonated bipyridine Ru(II) dye (RuP). The step-by-step construction of the MtrC/TiO2 system is monitored with (photo)electrochemistry, quartz-crystal microbalance with dissipation (QCM-D), and atomic force microscopy (AFM). Photocurrents are dependent on the redox state of the MtrC, confirming that electrons are transferred from the TiO2 nanocrystals to the surface via the MtrC conduit. In other words, in these TiO2/MtrC hybrid photodiodes, MtrC traps the conduction-band electrons from TiO2 before transferring them to the electrode, creating a photobioelectrochemical system in which a redox protein is used to mimic the efficient charge separation found in biological photosystems.

No MeSH data available.


Related in: MedlinePlus