The fluorescence intensity and lifetime of the 4,4′-difluoro-4-bora-5-(p-oxoalkyl)phenyl-3a,4a-diaza-s-indacene (1) show a strong correlation with viscosity medium due to viscosity-dependent twisting 5-phenyl group, which gives access dark nonemissive excited state. We propose sensitive versatile method for measuring local microviscosity in biological systems, based on determination 1. Fluorescence imaging (FLIM) performed live cells incubated 1 demonstrates distinct intracellular molecular...

We report intracellular fluorescence lifetime imaging (FLIM) and anisotropy measurements of two meso-substituted fluorophores based on the boron−dipyrrin (BODIPY) structure. Both dyes incorporate hydrophobic groups, which render them membrane-soluble. have obtained values for quantum yields, radiative nonradiative rate constants, lifetimes, time-resolved data in homogeneous methanol/glycerol solutions varying viscosities from 0.6 to 950 cP. find that lifetimes rotational correlation times...

Singlet molecular oxygen, O2(a1Δg), can be created in a single cell from ground-state O2(X3Σg−), upon focused laser irradiation of an intracellular sensitizer. This cytotoxic species subsequently detected by its 1270 nm phosphorescence (a1Δg → X3Σg−) with subcellular spatial resolution. The singlet oxygen lifetime determines diffusion distance and hence the volume element which singlet-oxygen-initiated perturbation occurs. In this study, time-resolved produced sensitizers chlorin (Chl)...

Understanding of cellular regulatory pathways that involve lipid membranes requires the detailed knowledge their physical state and structure. However, mapping viscosity diffusion in complex composition is currently a non-trivial technical challenge. We report fluorescence lifetime spectroscopy imaging (FLIM) meso-substituted BODIPY molecular rotor localised leaflet model various compositions. prepare large giant unilamellar vesicles (LUVs GUVs) containing phosphatidylcholine (PC) lipids...

Abstract We present polarization‐resolved fluorescence measurements of fluorescent molecular rotors 9‐(2‐carboxy‐2‐cyanovinyl)julolidine (CCVJ), 9‐(2,2‐dicyanovinyl)julolidine (DCVJ), and a meso ‐substituted boron dipyrromethene (BODIPY‐C 12 ). The photophysical properties these molecules are highly dependent on the viscosity surrounding solvent. relationship between their quantum yields medium is given by an equation first described presented Förster Hoffmann can be used to determine...

The only way to visually observe cellular viscosity, which can greatly influence biological reactions and has been linked several human diseases, is through viscosity imaging. Imaging allowed the mapping of in cells, next frontier targeted imaging organelles their microenvironments. Here we present a fluorescent molecular rotor/FLIM framework image both organellar membrane fluidity, using combination chemical targeting organelle extraction. For demonstration, matrix fluidity mitochondria,...

Modification of the structure a porphyrin dye shows significant change in rate charge recombination between injected electrons TiO2 and oxidized anchored to it following optical excitation, offering an insight into fundamental understanding processes occurring at dye/semiconductor interface.

Current photodynamic therapy (PDT) of cancer is limited by inefficiencies involved in specifically targeting photosensitizers to tumors. Although antibodies are being explored as vehicles, they present significant challenges, particularly terms pharmacokinetics and drug-coupling. We describe here a novel effective system covalently attach multiple photosensitizer molecules (both preclinical, pyropheophorbide-a clinically approved, verteporfin photosensitizers) single-chain Fvs. Further, we...

The sol-to-gel transition was monitored via the use of time-resolved recording fluorescence emission viscosity-sensitive probes. Two dyes were chosen for study, water-soluble DASPMI and a hydrophobic BODIPY, steady-state, time-tagged measurements performed. These techniques, coupled with probes different solubility, allowed complementary lifetime intensity data to be obtained from introduced into matrix-forming mixture produce sol−gel derived monoliths. precursors used as examples. A...

Sensing of the biophysical properties membranes using molecular reporters has recently regained widespread attention. This was elicited by development new probes exquisite optical and increased performance, combined with developments in fluorescence detection. Here, we report on lifetime imaging various rigid flexible fluorescent dyes to probe synthetic biological at steady state as well upon action external membrane-modifying agents. We tested solvatochromic Nile red...

The electroluminescent polymer blends with respect to the phosphorescent porphyrin, PtOEP were discussed. interactions between blend components based on charge transfer or neutral species studied. resulted in emission quenching of guest molecule phosphorescence.

Abstract Understanding viscosity in complex environments remains a largely unanswered question despite its importance determining reaction rates vivo. Here, time‐resolved fluorescence anisotropy imaging (TR‐FAIM) is combined with fluorescent molecular rotors (FMRs) to simultaneously determine two non‐equivalent viscosity‐related parameters heterogeneous environments. The parameters, FMR rotational correlation time and lifetime, are extracted from decays, which show dip‐and‐rise behavior due...

Photodynamic therapy (PDT) is a clinically-approved but rather under-exploited treatment modality for cancer and pre-cancerous superficial lesions. It utilises cold laser or LED to activate photochemical reaction between light activated drug (photosensitiser-drug) oxygen generate cytotoxic species. These free radical species damage cellular components leading cell death. Despite its benefits, the complexity, limited potency side effects of PDT have led poor general usage. However, research...

We report on the luminescence of a tetraphenylporphyrin, TPP-d, blended into poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene], MEH-PPV. find significant energy transfer from MEH-PPV to porphyrin, in spite low absorption porphyrin at emission wavelength MEH-PPV, reflected Förster radius (2.5 nm) smaller than for materials with larger spectral overlap. The overall photoluminescence, PL, efficiency decreases monotonically increasing content, whereas contribution total efficiency,...

We present a theoretical and experimental study of electrical pulsed excitation in polymer light-emitting diodes (LEDs). find that the low mobility results relatively high charge density within an electrically pumped structure. The broad spectrum charge-induced absorption its overlap with ground-state pose significant barrier for achieving net gain lasing. suggest approach might circumvent this problem using suitable emitters appropriate driving scheme. also methods ultrafast modulation LEDs...