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Structural and Functional Hierarchy in Photosynthetic Energy Conversion-from Molecules to Nanostructures.

Szabó T, Magyar M, Hajdu K, Dorogi M, Nyerki E, Tóth T, Lingvay M, Garab G, Hernádi K, Nagy L - Nanoscale Res Lett (2015)

Bottom Line: Recently, we adapted several physical and chemical methods for binding RCs to different nanomaterials.It is generally found that the P(+)(QAQB)(-) charge pair, which is formed after single saturating light excitation is stabilized after the attachment of the RCs to the nanostructures, which is followed by slow reorganization of the protein structure.This can be a basis of sensing element of bio-hybrid device for biosensor and/or optoelectronic applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Physics and Informatics, University of Szeged, Rerrich B. tér 1., H-6721, Szeged, Hungary. tiberatosz@gmail.com.

ABSTRACT
Basic principles of structural and functional requirements of photosynthetic energy conversion in hierarchically organized machineries are reviewed. Blueprints of photosynthesis, the energetic basis of virtually all life on Earth, can serve the basis for constructing artificial light energy-converting molecular devices. In photosynthetic organisms, the conversion of light energy into chemical energy takes places in highly organized fine-tunable systems with structural and functional hierarchy. The incident photons are absorbed by light-harvesting complexes, which funnel the excitation energy into reaction centre (RC) protein complexes containing redox-active chlorophyll molecules; the primary charge separations in the RCs are followed by vectorial transport of charges (electrons and protons) in the photosynthetic membrane. RCs possess properties that make their use in solar energy-converting and integrated optoelectronic systems feasible. Therefore, there is a large interest in many laboratories and in the industry toward their use in molecular devices. RCs have been bound to different carrier matrices, with their photophysical and photochemical activities largely retained in the nano-systems and with electronic connection to conducting surfaces. We show examples of RCs bound to carbon-based materials (functionalized and non-functionalized single- and multiwalled carbon nanotubes), transitional metal oxides (ITO) and conducting polymers and porous silicon and characterize their photochemical activities. Recently, we adapted several physical and chemical methods for binding RCs to different nanomaterials. It is generally found that the P(+)(QAQB)(-) charge pair, which is formed after single saturating light excitation is stabilized after the attachment of the RCs to the nanostructures, which is followed by slow reorganization of the protein structure. Measuring the electric conductivity in a direct contact mode or in electrochemical cell indicates that there is an electronic interaction between the protein and the inorganic carrier matrices. This can be a basis of sensing element of bio-hybrid device for biosensor and/or optoelectronic applications.

No MeSH data available.


Related in: MedlinePlus

a AFM image of the SWCNT/RC complex. RCs are bound to amine-functionalized SWCNTs. b Circular dichroism (CD) spectra of RC in detergent solution and bound to SWCNTs as indicated. c Absorption change of the SWCNT/RC complex at 450 nm after a single-turnover saturating Xe flash excitation at different incubation times, as indicated. d The amplitude of the absorption change of different RC samples as a function of the incubation time. Filled and empty circles and triangles represent RCs and SWCNT/RC complexes at room temperature and at 4 °C, respectively
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Fig6: a AFM image of the SWCNT/RC complex. RCs are bound to amine-functionalized SWCNTs. b Circular dichroism (CD) spectra of RC in detergent solution and bound to SWCNTs as indicated. c Absorption change of the SWCNT/RC complex at 450 nm after a single-turnover saturating Xe flash excitation at different incubation times, as indicated. d The amplitude of the absorption change of different RC samples as a function of the incubation time. Filled and empty circles and triangles represent RCs and SWCNT/RC complexes at room temperature and at 4 °C, respectively

Mentions: The long-term stability of the system, which depends on many internal and external factors, is very important for potential applications. Figure 6 shows results of different structural (AFM) and functional (CD, LD, flash photolysis) experiments showing the successful binding of RCs. It is to be noted that after 3 months, the stability drops very suddenly in every sample under the experimental conditions we conducted up to now [38]. However, in the absence of CNTs the inactivation is much faster. There are indirect (via monitoring flash-induced absorption change at specific wavelength or monitoring the redox state of the secondary quinone acceptor by EPR [37]) or direct (measuring the change in the light-induced conductivity of MWCNT bundles/RC composites [40]) proofs of redox interaction between CNTs and the RCs.Fig. 6


Structural and Functional Hierarchy in Photosynthetic Energy Conversion-from Molecules to Nanostructures.

Szabó T, Magyar M, Hajdu K, Dorogi M, Nyerki E, Tóth T, Lingvay M, Garab G, Hernádi K, Nagy L - Nanoscale Res Lett (2015)

a AFM image of the SWCNT/RC complex. RCs are bound to amine-functionalized SWCNTs. b Circular dichroism (CD) spectra of RC in detergent solution and bound to SWCNTs as indicated. c Absorption change of the SWCNT/RC complex at 450 nm after a single-turnover saturating Xe flash excitation at different incubation times, as indicated. d The amplitude of the absorption change of different RC samples as a function of the incubation time. Filled and empty circles and triangles represent RCs and SWCNT/RC complexes at room temperature and at 4 °C, respectively
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4666181&req=5

Fig6: a AFM image of the SWCNT/RC complex. RCs are bound to amine-functionalized SWCNTs. b Circular dichroism (CD) spectra of RC in detergent solution and bound to SWCNTs as indicated. c Absorption change of the SWCNT/RC complex at 450 nm after a single-turnover saturating Xe flash excitation at different incubation times, as indicated. d The amplitude of the absorption change of different RC samples as a function of the incubation time. Filled and empty circles and triangles represent RCs and SWCNT/RC complexes at room temperature and at 4 °C, respectively
Mentions: The long-term stability of the system, which depends on many internal and external factors, is very important for potential applications. Figure 6 shows results of different structural (AFM) and functional (CD, LD, flash photolysis) experiments showing the successful binding of RCs. It is to be noted that after 3 months, the stability drops very suddenly in every sample under the experimental conditions we conducted up to now [38]. However, in the absence of CNTs the inactivation is much faster. There are indirect (via monitoring flash-induced absorption change at specific wavelength or monitoring the redox state of the secondary quinone acceptor by EPR [37]) or direct (measuring the change in the light-induced conductivity of MWCNT bundles/RC composites [40]) proofs of redox interaction between CNTs and the RCs.Fig. 6

Bottom Line: Recently, we adapted several physical and chemical methods for binding RCs to different nanomaterials.It is generally found that the P(+)(QAQB)(-) charge pair, which is formed after single saturating light excitation is stabilized after the attachment of the RCs to the nanostructures, which is followed by slow reorganization of the protein structure.This can be a basis of sensing element of bio-hybrid device for biosensor and/or optoelectronic applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Physics and Informatics, University of Szeged, Rerrich B. tér 1., H-6721, Szeged, Hungary. tiberatosz@gmail.com.

ABSTRACT
Basic principles of structural and functional requirements of photosynthetic energy conversion in hierarchically organized machineries are reviewed. Blueprints of photosynthesis, the energetic basis of virtually all life on Earth, can serve the basis for constructing artificial light energy-converting molecular devices. In photosynthetic organisms, the conversion of light energy into chemical energy takes places in highly organized fine-tunable systems with structural and functional hierarchy. The incident photons are absorbed by light-harvesting complexes, which funnel the excitation energy into reaction centre (RC) protein complexes containing redox-active chlorophyll molecules; the primary charge separations in the RCs are followed by vectorial transport of charges (electrons and protons) in the photosynthetic membrane. RCs possess properties that make their use in solar energy-converting and integrated optoelectronic systems feasible. Therefore, there is a large interest in many laboratories and in the industry toward their use in molecular devices. RCs have been bound to different carrier matrices, with their photophysical and photochemical activities largely retained in the nano-systems and with electronic connection to conducting surfaces. We show examples of RCs bound to carbon-based materials (functionalized and non-functionalized single- and multiwalled carbon nanotubes), transitional metal oxides (ITO) and conducting polymers and porous silicon and characterize their photochemical activities. Recently, we adapted several physical and chemical methods for binding RCs to different nanomaterials. It is generally found that the P(+)(QAQB)(-) charge pair, which is formed after single saturating light excitation is stabilized after the attachment of the RCs to the nanostructures, which is followed by slow reorganization of the protein structure. Measuring the electric conductivity in a direct contact mode or in electrochemical cell indicates that there is an electronic interaction between the protein and the inorganic carrier matrices. This can be a basis of sensing element of bio-hybrid device for biosensor and/or optoelectronic applications.

No MeSH data available.


Related in: MedlinePlus