In situ Time-Resolved Spectroelectrochemistry Reveals Limitations of Biohybrid Photoelectrode Performance

Nawrocki, Wojciech J.; Jones, Michael R.; Frese, Raoul N.; Croce, Roberta; Friebe, Vincent M.

doi:10.2139/ssrn.4149955

Cited by 2 publications

(6 citation statements)

References 62 publications

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“…The biophotoelectrode activity was measured in an electrochemical cell containing 1.5 mM water-soluble ubiquinone-0 (Q 0 ) as an electron acceptor at an applied potential of +160 mV versus the standard hydrogen electrode (SHE). To exclude acceptor side (i.e., Q B /Q 0 ) limitations or short-circuits from controlling RC turnover, 4 the light intensity was lowered to 2.6 mW cm –2 such that peak photocurrents were in a linear regime with respect to the light intensity ( Figure S2 ). To characterize dependence on its concentration, cyt c was titrated into the electrolyte, and, after equilibration, the photocurrent during 30 s of illumination was recorded ( Figure 3 a).…”

Section: Resultsmentioning

confidence: 99%

“…The high efficiency and adaptability of natural photosynthetic reaction center (RC) proteins underpin their potential as sustainable components in biohybrid photoelectrodes for solar energy conversion and applications such as biosensing. , These intramembrane pigment proteins use light energy to separate charge across the photosynthetic membrane followed by external electron transfer that stabilizes the intraprotein charge separation and hence the energy conversion. A principal challenge in the development of biohybrid RC photoelectrodes is achieving an efficient transfer of electrons from the electrode following photochemical charge separation within the RC . The electrostatic interactions occurring between proteins and the electrode, and between adjacent proteins, form interfacial boundaries that may result in kinetic bottlenecks in the biohybrid electron transfer chain .…”

Section: Introductionmentioning

confidence: 99%

“…A principal challenge in the development of biohybrid RC photoelectrodes is achieving an efficient transfer of electrons from the electrode following photochemical charge separation within the RC. 4 The electrostatic interactions occurring between proteins and the electrode, 5 and between adjacent proteins, 6 form interfacial boundaries that may result in kinetic bottlenecks in the biohybrid electron transfer chain. 4 Improvement of the performance of biophotoelectrodes requires a better understanding of the impact of these interfaces on electron transfer from the electrode.…”

Section: Introductionmentioning

confidence: 99%

“… 4 The electrostatic interactions occurring between proteins and the electrode, 5 and between adjacent proteins, 6 form interfacial boundaries that may result in kinetic bottlenecks in the biohybrid electron transfer chain. 4 Improvement of the performance of biophotoelectrodes requires a better understanding of the impact of these interfaces on electron transfer from the electrode.…”

Section: Introductionmentioning

confidence: 99%

“…A recent study using spectroelectrochemistry has shown that a limiting factor for RC turnover on an electrode is a kinetic bottleneck associated with cyt c- mediated electron transfer, 4 indicating a parameter that could be adjusted for better overall performance. In the present work, we characterized biophotoelectrode performance in response to modifications expected to impact the electrostatic interfaces between the RC and cyt c and cyt c and an electrode.…”

Section: Introductionmentioning

confidence: 99%

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The Role of Electrostatic Binding Interfaces in the Performance of Bacterial Reaction Center Biophotoelectrodes

Moort

Jones

Frese

et al. 2023

ACS Sustainable Chem. Eng.

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Photosynthetic reaction centers (RCs) efficiently capture and convert solar radiation into electrochemical energy. Accordingly, RCs have the potential as components in biophotovoltaics, biofuel cells, and biosensors. Recent biophotoelectrodes containing the RC from the bacterium Rhodobacter sphaeroides utilize a natural electron donor, horse heart cytochrome c (cyt c), as an electron transfer mediator with the electrode. In this system, electrostatic interfaces largely control the protein–electrode and protein–protein interactions necessary for electron transfer. However, recent studies have revealed kinetic bottlenecks in cyt-mediated electron transfer that limit biohybrid photoelectrode efficiency. Here, we seek to understand how changing protein–protein and protein–electrode interactions influence RC turnover and biophotoelectrode efficiency. The RC–cyt c binding interaction was modified by substituting interfacial RC amino acids. Substitutions Asn-M188 to Asp and Gln-L264 to Glu, which are known to produce a higher cyt-binding affinity, led to a decrease in the RC turnover frequency (TOF) at the electrode, suggesting that a decrease in cyt c dissociation was rate-limiting in these RC variants. Conversely, an Asp-M88 to Lys substitution producing a lower binding affinity had little effect on the RC TOF, suggesting that a decrease in the cyt c association rate was not a rate-limiting factor. Modulating the electrode surface with a self-assembled monolayer that oriented the cyt c to face the electrode did not affect the RC TOF, suggesting that the orientation of cyt c was also not a rate-limiting factor. Changing the ionic strength of the electrolyte solution had the most potent impact on the RC TOF, indicating that cyt c mobility was important for effective electron donation to the photo-oxidized RC. An ultimate limitation for the RC TOF was that cyt c desorbed from the electrode at ionic strengths above 120 mM, diluting its local concentration near the electrode-adsorbed RCs and resulting in poor biophotoelectrode performance. These findings will guide further tuning of these interfaces for improved performance.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The Role of Electrostatic Binding Interfaces in the Performance of Bacterial Reaction Center Biophotoelectrodes

Moort

Jones

Frese

et al. 2023

ACS Sustainable Chem. Eng.

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Rewiring photosynthetic electron transport chains for solar energy conversion

Lawrence,

Egan,

Hoefer

et al. 2023

Nat Rev Bioeng

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Photosynthetic organisms have evolved versatile electron transport chains capable of the efficient conversion of solar energy into chemical energy. Researchers can engineer these electron transport pathways to drive new-to-nature processes in a class of systems we term "rewired photosynthetic electron transport chains" (R-PETCs). R-PETCs can be used for the light-driven production of electricity or chemicals and exhibit numerous advantages over the synthetic systems widely used for these applications, including enhanced stability, versatility, and sustainability. In this review we summarise the current state of R-PETC research, highlighting major advances alongside outstanding research problems. We also provide descriptions of R-PETC development, outlining the different classes of R-PETCs, the research tools used in their construction, and the key design considerations important for achieving high-performances. Finally, we identify future avenues for R-PETC research which we expect will enhance performances sufficiently to make these systems suitable for a variety of real-world applications.

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In situ Time-Resolved Spectroelectrochemistry Reveals Limitations of Biohybrid Photoelectrode Performance

Cited by 2 publications

References 62 publications

The Role of Electrostatic Binding Interfaces in the Performance of Bacterial Reaction Center Biophotoelectrodes

The Role of Electrostatic Binding Interfaces in the Performance of Bacterial Reaction Center Biophotoelectrodes

Rewiring photosynthetic electron transport chains for solar energy conversion

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