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Silica nanoparticles for the layer-by-layer assembly of fully electro-active cytochrome c multilayers.

Feifel SC, Lisdat F - J Nanobiotechnology (2011)

Bottom Line: Moreover, the combination of nanoparticles with biomolecules on electrodes is a matter of particular interest since several examples with high activities and direct electron transfer have been found.This study demonstrates the ability to construct fully electro-active cyt c multilayer assemblies by using carboxy-modified silica nanoparticles.Thus it can be shown that functional, artificial systems can be build up following natural examples of protein arrangements.

View Article: PubMed Central - HTML - PubMed

Affiliation: Biosystems Technology, University of Applied Sciences, Wildau 15745, Germany. feifel@th-wildau.de

ABSTRACT

Background: For bioanalytical systems sensitivity and biomolecule activity are critical issues. The immobilization of proteins into multilayer systems by the layer-by-layer deposition has become one of the favorite methods with this respect. Moreover, the combination of nanoparticles with biomolecules on electrodes is a matter of particular interest since several examples with high activities and direct electron transfer have been found. Our study describes the investigation on silica nanoparticles and the redox protein cytochrome c for the construction of electro-active multilayer architectures, and the electron transfer within such systems. The novelty of this work is the construction of such artificial architectures with a non-conducting building block. Furthermore a detailed study of the size influence of silica nanoparticles is performed with regard to formation and electrochemical behavior of these systems.

Results: We report on interprotein electron transfer (IET) reaction cascades of cytochrome c (cyt c) immobilized by the use of modified silica nanoparticles (SiNPs) to act as an artificial matrix. The layer-by-layer deposition technique has been used for the formation of silica particles/cytochrome c multilayer assemblies on electrodes. The silica particles are characterized by dynamic light scattering (DLS), Fourier transformed infrared spectroscopy (FT-IR), Zeta-potential and transmission electron microscopy (TEM). The modified particles have been studied with respect to act as an artificial network for cytochrome c and to allow efficient interprotein electron transfer reactions. We demonstrate that it is possible to form electro-active assemblies with these non-conducting particles. The electrochemical response is increasing linearly with the number of layers deposited, reaching a cyt c surface concentration of about 80 pmol/cm2 with a 5 layer architecture. The interprotein electron transfer through the layer system and the influence of particle size are discussed.

Conclusions: This study demonstrates the ability to construct fully electro-active cyt c multilayer assemblies by using carboxy-modified silica nanoparticles. Thus it can be shown that functional, artificial systems can be build up following natural examples of protein arrangements. The absence of any conductive properties in the second building block clearly demonstrates that mechanisms for electron transfer through such protein multilayer assemblies is based on interprotein electron exchange, rather than on wiring of the protein to the electrode.The construction strategy of this multilayer system provides a new controllable route to immobilize proteins in multiple layers featuring direct electrochemistry without mediating shuttle molecules and controlling the electro-active amount by the number of deposition steps.

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Schematic representation of the SiNPs/cyt c multilayer architecture. Schematic representation of an SiNPs/cyt c multilayer assembly prepared on a monolayer electrode (M). Layer structure [SiNPs/cyt c]n (n = 1, 2, 3, 4). Yellow arrows indicate the direct electron transfer between the cyt c molecules and onto the electrode.
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Figure 6: Schematic representation of the SiNPs/cyt c multilayer architecture. Schematic representation of an SiNPs/cyt c multilayer assembly prepared on a monolayer electrode (M). Layer structure [SiNPs/cyt c]n (n = 1, 2, 3, 4). Yellow arrows indicate the direct electron transfer between the cyt c molecules and onto the electrode.

Mentions: The demonstrated binding forces between SiNPs and cyt c are strong enough for the arrangement of layered architectures, but this is only one precondition for a functional system with an electro-active protein. To ascertain the electrochemical characteristics, SiNP/cyt c multilayers have been prepared on a MU/MUA modified gold electrode. The SiNPs are introduced in the cyt c assemblies as schematically illustrated in Figure 6.


Silica nanoparticles for the layer-by-layer assembly of fully electro-active cytochrome c multilayers.

Feifel SC, Lisdat F - J Nanobiotechnology (2011)

Schematic representation of the SiNPs/cyt c multilayer architecture. Schematic representation of an SiNPs/cyt c multilayer assembly prepared on a monolayer electrode (M). Layer structure [SiNPs/cyt c]n (n = 1, 2, 3, 4). Yellow arrows indicate the direct electron transfer between the cyt c molecules and onto the electrode.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3278367&req=5

Figure 6: Schematic representation of the SiNPs/cyt c multilayer architecture. Schematic representation of an SiNPs/cyt c multilayer assembly prepared on a monolayer electrode (M). Layer structure [SiNPs/cyt c]n (n = 1, 2, 3, 4). Yellow arrows indicate the direct electron transfer between the cyt c molecules and onto the electrode.
Mentions: The demonstrated binding forces between SiNPs and cyt c are strong enough for the arrangement of layered architectures, but this is only one precondition for a functional system with an electro-active protein. To ascertain the electrochemical characteristics, SiNP/cyt c multilayers have been prepared on a MU/MUA modified gold electrode. The SiNPs are introduced in the cyt c assemblies as schematically illustrated in Figure 6.

Bottom Line: Moreover, the combination of nanoparticles with biomolecules on electrodes is a matter of particular interest since several examples with high activities and direct electron transfer have been found.This study demonstrates the ability to construct fully electro-active cyt c multilayer assemblies by using carboxy-modified silica nanoparticles.Thus it can be shown that functional, artificial systems can be build up following natural examples of protein arrangements.

View Article: PubMed Central - HTML - PubMed

Affiliation: Biosystems Technology, University of Applied Sciences, Wildau 15745, Germany. feifel@th-wildau.de

ABSTRACT

Background: For bioanalytical systems sensitivity and biomolecule activity are critical issues. The immobilization of proteins into multilayer systems by the layer-by-layer deposition has become one of the favorite methods with this respect. Moreover, the combination of nanoparticles with biomolecules on electrodes is a matter of particular interest since several examples with high activities and direct electron transfer have been found. Our study describes the investigation on silica nanoparticles and the redox protein cytochrome c for the construction of electro-active multilayer architectures, and the electron transfer within such systems. The novelty of this work is the construction of such artificial architectures with a non-conducting building block. Furthermore a detailed study of the size influence of silica nanoparticles is performed with regard to formation and electrochemical behavior of these systems.

Results: We report on interprotein electron transfer (IET) reaction cascades of cytochrome c (cyt c) immobilized by the use of modified silica nanoparticles (SiNPs) to act as an artificial matrix. The layer-by-layer deposition technique has been used for the formation of silica particles/cytochrome c multilayer assemblies on electrodes. The silica particles are characterized by dynamic light scattering (DLS), Fourier transformed infrared spectroscopy (FT-IR), Zeta-potential and transmission electron microscopy (TEM). The modified particles have been studied with respect to act as an artificial network for cytochrome c and to allow efficient interprotein electron transfer reactions. We demonstrate that it is possible to form electro-active assemblies with these non-conducting particles. The electrochemical response is increasing linearly with the number of layers deposited, reaching a cyt c surface concentration of about 80 pmol/cm2 with a 5 layer architecture. The interprotein electron transfer through the layer system and the influence of particle size are discussed.

Conclusions: This study demonstrates the ability to construct fully electro-active cyt c multilayer assemblies by using carboxy-modified silica nanoparticles. Thus it can be shown that functional, artificial systems can be build up following natural examples of protein arrangements. The absence of any conductive properties in the second building block clearly demonstrates that mechanisms for electron transfer through such protein multilayer assemblies is based on interprotein electron exchange, rather than on wiring of the protein to the electrode.The construction strategy of this multilayer system provides a new controllable route to immobilize proteins in multiple layers featuring direct electrochemistry without mediating shuttle molecules and controlling the electro-active amount by the number of deposition steps.

Show MeSH
Related in: MedlinePlus