Counting Single Redox Turnovers: Fluorogenic Antioxidant Conversion and Mass Transport Visualization via Single Molecule Spectroelectrochemistry

Godin, Robert; Cosa, Gonzalo

doi:10.1021/acs.jpcc.6b06183

Cited by 17 publications

(11 citation statements)

References 44 publications

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“…These are two‐segment trap‐reporter (chromanol‐BODIPY) probes that become fluorescent upon trapping lipid peroxyl radicals. The new probes have been instrumental in monitoring ROS within lipid membranes in high throughput, within single cells and in single molecule studies . The preserved chromanol head group in the probes has warranted for highly efficient trapping of lipid peroxyl radicals, the chain carriers in lipid chain auto‐oxidation (rate constants of 3 × 10 6 m −1 s −1 and 6 × 10 3 m −1 s −1 have been reported for α ‐tocopherol in homogeneous solution and lipid bilayers, respectively ).…”

Section: Introductionmentioning

confidence: 99%

Tuning Photoinduced Electron Transfer Efficiency of Fluorogenic BODIPY‐α‐Tocopherol Analogues

Greene

Lincoln

Cosa

2018

Photochem & Photobiology

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Fluorogenic analogues of α‐tocopherol developed by our group have been instrumental in monitoring reactive oxygen species (ROS) within lipid membranes. Prepared as two‐segment trap‐reporter (chromanol‐BODIPY) probes, photoinduced electron transfer (PeT) was utilized to provide these probes with an off/on switch mechanism warranting the necessary sensitivity. Herein, we rationalize within the context of Marcus theory of electron transfer how substituents on the BODIPY core and linker length joining the trap and reporter segments, tune PeT efficiency. DFT and electrochemical studies were used to estimate the thermodynamic driving force of PeT in our constructs. By tuning the redox potential over a 400 mV range, we observed over an order of magnitude increase in PeT efficiency. Increasing the linker length between the chromanol and BODIPY by 2.8 angstroms, in turn, decreased PeT efficiency 2.7‐fold. Our results illustrate how substituent and linker choice enable “darkening” the off state of fluorogenic probes based on BODIPY fluorophores, by favoring PeT over radiative emission from the singlet excited state manifold. Ultimately, our work brings light to the sensitivity ceiling one may achieve in developing fluorogenic antioxidant analogues of α‐tocopherol. The work provides general guidelines applicable to those developing fluorogenic probes based on PeT.

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Section: Introductionmentioning

confidence: 99%

Tuning Photoinduced Electron Transfer Efficiency of Fluorogenic BODIPY‐α‐Tocopherol Analogues

Greene

Lincoln

Cosa

2018

Photochem & Photobiology

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“…B-VK Q displays reversible turn-on fluorescence upon two-electron and two-proton reduction of the menadione moiety to its menadiol counterpart. It retains the redox specificity and reversibility imparted from the menadione moiety, as validated via a suite of chemical reactions and SEC techniques . Our own SEC studies provide preliminary results in this direction.…”

Section: Discussionmentioning

confidence: 70%

“…In order to correlate applied redox potential with emission intensity for B-VK Q upon its electrochemical reduction, we turned to fluorescence microscopy-based spectroelectrochemistry (SEC), a powerful tool that allows for monitoring trace amounts of fluorescent molecules under electrochemical control. − SEC experiments were performed on a confocal microscope setup to enable visualization of newly generated fluorescent compounds (Figure A). An electrochemical cell was custom-built by gluing a glass tube on top of a coverslip coated with optically transparent platinized ITO (working electrode).…”

Section: Resultsmentioning

confidence: 99%

Monitoring Chemical and Biological Electron Transfer Reactions with a Fluorogenic Vitamin K Analogue Probe

et al. 2016

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We report herein the design, synthesis, and characterization of a two-segment fluorogenic analogue of vitamin K, B-VK, prepared by coupling vitamin K, also known as menadione (a quinone redox center), to a boron-dipyrromethene (BODIPY) fluorophore (a lipophilic reporter segment). Oxidation-reduction reactions, spectroelectrochemical studies, and enzymatic assays conducted in the presence of DT-diaphorase illustrate that the new probe shows reversible redox behavior on par with that of vitamin K, provides a high-sensitivity fluorescence signal, and is compatible with biological conditions, opening the door to monitor remotely (i.e., via imaging) redox processes in real time. In its oxidized form, B-VK is non-emissive, while upon reduction to the hydroquinone form, B-VK, BODIPY fluorescence is restored, with emission quantum yield values of ca. 0.54 in toluene. Density functional theory studies validate a photoinduced electron transfer intramolecular switching mechanism, active in the non-emissive quinone form and deactivated upon reduction to the emissive dihydroquinone form. Our results highlight the potential of B-VK as a fluorogenic probe to study electron transfer and transport in model systems and biological structures with optimal sensitivity and desirable chemical specificity. Use of such a probe may enable a better understanding of the role that vitamin K plays in biological redox reactions ubiquitous in key cellular processes, and help elucidate the mechanism and pathological significance of these reactions in biological systems.

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“…Raman is a technique with low sensitivity but it can be largely improved using surface enhanced Raman scattering (SERS) substrates . Finally, fluorescence is a really sensitive and selective technique making it easy to work at a suitable time‐scale.…”

Section: Whatmentioning

confidence: 99%

Spectroelectrochemical Sensing: Current Trends and Challenges

et al. 2019

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Spectroelectrochemistry (SEC) has been used for more than 50 years, but this set of techniques has not been widely used for quantitative analysis. For many years, no commercial instruments were available, which made very difficult to spread the use of SEC. Nowadays, only the creativity of the researchers is required to exploit the capabilities of SEC. This review is written with the aim of showing the potential of SEC, mainly for analytical chemistry. Here, we explain what SEC is, how analytical responses can be obtained, why these techniques are useful for sensors, with a brief description of its advantages in use, and, finally, we try to show the challenges that must be addressed in the next years. SEC can resolve interesting analytical problems using the high amount of data provided by this intrinsic trilinear technique. Given the quantitative analysis point of view of this review, the discussion of the SEC techniques is focused on UV/Vis absorption, photoluminescence and Raman SEC.

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Counting Single Redox Turnovers: Fluorogenic Antioxidant Conversion and Mass Transport Visualization via Single Molecule Spectroelectrochemistry

Cited by 17 publications

References 44 publications

Tuning Photoinduced Electron Transfer Efficiency of Fluorogenic BODIPY‐α‐Tocopherol Analogues

Tuning Photoinduced Electron Transfer Efficiency of Fluorogenic BODIPY‐α‐Tocopherol Analogues

Monitoring Chemical and Biological Electron Transfer Reactions with a Fluorogenic Vitamin K Analogue Probe

Spectroelectrochemical Sensing: Current Trends and Challenges

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