Direct Observation of Triplet State Emission of Single Molecules:  Single Molecule Phosphorescence Quenching of Metalloporphyrin and Organometallic Complexes by Molecular Oxygen and Their Quenching Rate Distributions

2003 ◽  
Vol 125 (43) ◽  
pp. 13198-13204 ◽  
Author(s):  
Erwen Mei ◽  
Sergei Vinogradov ◽  
Robin M. Hochstrasser
Keyword(s):  
Triplet State ◽  
Molecular Oxygen ◽  
Direct Observation ◽  
Single Molecule ◽  
Single Molecules ◽  
Organometallic Complexes ◽  
Quenching Rate ◽  
Phosphorescence Quenching

Photophysics of novel 22π porphyrinoids

2012 ◽  
Vol 16 (05n06) ◽  
pp. 499-507 ◽  
Author(s):  
Daniel O. Mártire ◽  
Sigrid Russell ◽  
Hans-Jürgen Dietrich ◽  
Carlos J. Cobos ◽  
Silvia E. Braslavsky
Keyword(s):  
Triplet State ◽  
Molecular Oxygen ◽  
Photophysical Properties ◽  
Intersystem Crossing ◽  
Quenching Rate ◽  
Triplet Energy ◽  
Singlet Molecular Oxygen ◽  
Time Resolved ◽  
Quenching Rate Constant ◽  
New Compounds

The photophysical properties of toluene solutions of two new 22π expanded porphycene compounds were measured using a combination of various steady-state and time-resolved techniques. The determined triplet energy (E T = 109 ± 3) kJ.mol-1, coincident with the calculated E T = (96.0 ± 10) kJ.mol-1, of both red absorbing compounds is higher than the energy required to excite ground state molecular oxygen to singlet molecular oxygen. However, the intersystem crossing yield is very low (ca. 10-2), which makes these compounds poor photosensitizers. The triplet state yield of the two expanded 22π porphyrinoid compounds is much lower than that of the parent porphycene, whereas their fluorescence is as high (ca. 30%) as the value for porphycene. The slower than diffusional quenching rate constant of a porphycene triplet state by the two new compounds reflects a steric hindering factor of the exothermic energy transfer.

scholarly journals Three-dimensional total-internal reflection fluorescence nanoscopy with nanometric axial resolution by photometric localization of single molecules

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Alan M. Szalai ◽  
Bruno Siarry ◽  
Jerónimo Lukin ◽  
David J. Williamson ◽  
Nicolás Unsain ◽  
...  
Keyword(s):  
Single Molecule ◽  
Total Internal Reflection ◽  
Single Molecules ◽  
Fluorescence Microscope ◽  
Internal Reflection ◽  
Total Internal Reflection Fluorescence ◽  
Axial Position ◽  
Localization Microscopy ◽  
Localization Precision ◽  
Single Molecule Localization Microscopy

AbstractSingle-molecule localization microscopy enables far-field imaging with lateral resolution in the range of 10 to 20 nanometres, exploiting the fact that the centre position of a single-molecule’s image can be determined with much higher accuracy than the size of that image itself. However, attaining the same level of resolution in the axial (third) dimension remains challenging. Here, we present Supercritical Illumination Microscopy Photometric z-Localization with Enhanced Resolution (SIMPLER), a photometric method to decode the axial position of single molecules in a total internal reflection fluorescence microscope. SIMPLER requires no hardware modification whatsoever to a conventional total internal reflection fluorescence microscope and complements any 2D single-molecule localization microscopy method to deliver 3D images with nearly isotropic nanometric resolution. Performance examples include SIMPLER-direct stochastic optical reconstruction microscopy images of the nuclear pore complex with sub-20 nm axial localization precision and visualization of microtubule cross-sections through SIMPLER-DNA points accumulation for imaging in nanoscale topography with sub-10 nm axial localization precision.

Interfacial charge transfer events of BODIPY molecules: single molecule spectroelectrochemistry and substrate effects

2014 ◽  
Vol 16 (42) ◽  
pp. 23150-23156 ◽  
Author(s):  
Jia Liu ◽  
Caleb M. Hill ◽  
Shanlin Pan ◽  
Haiying Liu
Keyword(s):  
Charge Transfer ◽  
Single Molecule ◽  
Single Molecules ◽  
Transfer Mechanism ◽  
Substrate Effects ◽  
Interfacial Charge Transfer ◽  
Charge Transfer Mechanism ◽  
Nanostructured Substrates ◽  
Interfacial Charge

BODIPY dye single molecules on nanostructured substrates are studied with a single molecule spectroelectrochemistry technique to reveal the heterogeneous charge transfer mechanism.

scholarly journals A method for imaging single molecules at the plasma membrane of live cells within tissue slices

2020 ◽  
Vol 153 (1) ◽  
Author(s):  
Gregory I. Mashanov ◽  
Tatiana A. Nenasheva ◽  
Tatiana Mashanova ◽  
Catherine Maclachlan ◽  
Nigel J.M. Birdsall ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Lines ◽  
Single Molecule ◽  
Cardiac Tissue ◽  
Single Molecules ◽  
Live Cells ◽  
Biological Macromolecules ◽  
Tissue Slices ◽  
Tissue Samples ◽  
Mammalian Cell Lines

Recent advances in light microscopy allow individual biological macromolecules to be visualized in the plasma membrane and cytosol of live cells with nanometer precision and ∼10-ms time resolution. This allows new discoveries to be made because the location and kinetics of molecular interactions can be directly observed in situ without the inherent averaging of bulk measurements. To date, the majority of single-molecule imaging studies have been performed in either unicellular organisms or cultured, and often chemically fixed, mammalian cell lines. However, primary cell cultures and cell lines derived from multi-cellular organisms might exhibit different properties from cells in their native tissue environment, in particular regarding the structure and organization of the plasma membrane. Here, we describe a simple approach to image, localize, and track single fluorescently tagged membrane proteins in freshly prepared live tissue slices and demonstrate how this method can give information about the movement and localization of a G protein–coupled receptor in cardiac tissue slices. In principle, this experimental approach can be used to image the dynamics of single molecules at the plasma membrane of many different soft tissue samples and may be combined with other experimental techniques.

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