Integration of a superconducting nanowire single-photon detector into a confocal microscope for time-resolved photoluminescence (TRPL)-mapping: Sensitivity and time resolution.

This report highlights the combination of the MicroTime 100 upright confocal fluorescence lifetime microscope with a Single Quantum Eos Superconducting Nanowire Single-Photon Detector (SNSPD) system as a powerful tool for photophysical research and applications. We focus on an application in materials science, photoluminescence imaging, and lifetime characterization of Cu(InGa)Se (CIGS) devices intended for solar cells. We demonstrate improved sensitivity, signal-to-noise ratio, and time-resolution in combination with confocal spatial resolution in the near-infrared (NIR) range, specifically in the 1000-1300 nm range.

Flow cytometry-based FRET identifies binding intensities in PPARγ1 protein-protein interactions in living cells.

PPARγ is a pharmacological target in inflammatory and metabolic diseases. Upon agonistic treatment or following antagonism, binding of co-factors is altered, which consequently affects PPARγ-dependent transactivation as well as its DNA-independent properties. Therefore, establishing techniques to characterize these interactions is an important issue in living cells.

Novel zinc phthalocyanine as a promising photosensitizer for photodynamic treatment of esophageal cancer.

Photodynamic therapy (PDT) has gathered much attention in the field of cancer treatment and is increasingly used as an alternative solution for esophageal cancer therapy. However, there is a constant need for improving the effectiveness and tolerability of the applied photosensitizers (PS). Here, we propose tetra-triethyleneoxysulfonyl substituted zinc phthalocyanine (ZnPc) as a promising PS for photodynamic treatment of esophageal cancer.

An artificial photosynthetic model based on a molecular triad of boron dipyrromethene and phthalocyanine.

A boron dipyrromethene (BDP) unit and its monostyryl derivative (MSBDP) were introduced at the axial positions of a silicon(iv) phthalocyanine (SiPc) core. The absorption spectrum of this compound virtually covered the entire visible region (300-700 nm) and could be interpreted as a superposition of the spectra of individual components. The intramolecular photoinduced energy and charge transfer processes of this triad were studied using steady-state and time-resolved spectroscopic methods in polar and nonpolar solvents.

Tetra-triethyleneoxysulfonyl substituted zinc phthalocyanine for photodynamic cancer therapy.

Photodynamic therapy (PDT) has emerged as an effective and minimally invasive treatment option for several diseases, including some forms of cancer. However, several drawbacks of the approved photosensitizers (PS), such as insufficient light absorption at therapeutically relevant wavelengths hampered the clinical effectiveness of PDT. Phthalocyanines (Pc) are interesting PS-candidates with a strong light absorption in the favourable red spectral region and a high quantum yield of cancer cell destroying singlet oxygen generation.

Brightness through local constraint--LNA-enhanced FIT hybridization probes for in vivo ribonucleotide particle tracking.

Imaging the dynamics of RNA in living cells is usually performed by means of transgenic approaches that require modification of RNA targets and cells. Fluorogenic hybridization probes would also allow the analysis of wild-type organisms. We developed nuclease-resistant DNA forced intercalation (FIT) probes that combine the high enhancement of fluorescence upon hybridization with the high brightness required to allow tracking of individual ribonucleotide particles (RNPs).

Synthesis and characterization of quantum dots designed for biomedical use.

Semiconductor quantum dots (QDs) have become promising nanoparticles for a wide variety of biomedical applications. However, the major drawback of QDs is their potential toxicity. Here, we determined possible cytotoxic effects of a set of QDs by systematic photophysical evaluation in vitro as well as in vivo.

Tracking of fluorescence nanoparticles with nanometre resolution in a biological system: assessing local viscosity and microrheology.

The aim of the study was to establish a user-friendly approach for single fluorescence particle 3D localization and tracking with nanometre precision in a standard fluorescence microscope using a point spread function (PSF) approach, and to evaluate validity and precision for different analysis methods and optical conditions with particular application to microcirculatory flow dynamics and cell biology. Images of fluorescent particles were obtained with a standard fluorescence microscope equipped with a piezo positioner for the objective. Whole pattern (WP) comparison with a PSF recorded for the specific set-up and measurement of the outermost ring radius (ORR) were used for analysis.

Formation and photoinduced processes of the host-guest complexes of a β-cyclodextrin-conjugated aza-BODIPY and tetrasulfonated porphyrins.

A bis(permethylated β-cyclodextrin)-substituted aza-BODIPY has been prepared, which forms stable 1 : 1 host-guest complexes with metal-free and zinc(II) tetrasulfonated porphyrins in water. The resulting complexes exhibit predominantly a photoinduced energy or electron transfer process depending on the porphyrin-based guest.

Photoinduced energy and charge transfer in a p-phenylene-linked dyad of boron dipyrromethene and monostyryl boron dipyrromethene.

Boron dipyrromethenes (BDPs) are excellent building blocks for design of artificial light harvesting and charge separation systems. In the present work, we report the results of photophysical studies of a novel dyad, in which a BDP and a mono-styryl BDP (MSBDP) are covalently linked to each other at the meso-position via a p-phenylene unit. It was found that the photophysical properties of the dyad dissolved in polar as well as nonpolar solvents are strongly affected by two different types of interactions between the BDP and MSBDP parts, namely excitation energy transfer and photoinduced electron transfer.

A boron dipyrromethene-phthalocyanine pentad as an artificial photosynthetic model.

A silicon(IV) phthalocyanine with two axial p-phenylene-linked boron dipyrromethene and monostyryl boron dipyrromethene moieties has been prepared. The resulting pentad absorbs strongly in most of the UV-visible region and serves as an artificial photosynthetic antenna-reaction centre model.

Sequential energy and charge transfer processes in mixed host-guest complexes of subphthalocyanine, porphyrin and phthalocyanine chromophores.

Porphyrins, phthalocyanines and subphthalocyanines are three attractive classes of chromophores with intriguing properties making them suitable for the design of artificial photosynthetic systems. The assembly of these components by a supramolecular approach is of particular interest as it provides a facile means to build multi-chromophoric arrays with various architectures and tuneable photophysical properties. In this paper, we show the formation of mixed host-guest supramolecular complexes that consist of a β-cyclodextrin-conjugated subphthalocyanine, a tetrasulfonated porphyrin and a series of silicon(IV) phthalocyanines substituted axially with two β-cyclodextrins via different spacers.

Formation and photoinduced processes of a self-assembled subphthalocyanine-porphyrin-phthalocyanine supramolecular complex.

We report herein the formation and excitation energy transfer property of a ternary supramolecular complex of subphthalocyanine-porphyrin-phthalocyanine held by host-guest interactions.

Switching the photoinduced processes in host-guest complexes of β-cyclodextrin-substituted silicon(IV) phthalocyanines and a tetrasulfonated porphyrin.

Porphyrins and phthalocyanines are two attractive classes of functional dyes for the construction of artificial light harvesting and charge separation molecular systems. The assembly of these components by supramolecular approach is of particular interest as this provides a facile route to build multi-chromophoric arrays with various architectures and tuneable photophysical properties. We report herein a series of host-guest complexes formed between a tetrasulfonated porphyrin and several silicon(IV) phthalocyanines substituted axially with two permethylated β-cyclodextrin units via different spacers.

Formation and energy transfer property of a subphthalocyanine-porphyrin complex held by host-guest interactions.

A stable 2 : 1 host-guest complex is formed between a beta-cyclodextrin-conjugated subphthalocyanine and a tetrasulfonated porphyrin in water. The complex exhibits an energy transfer property from the excited subphthalocyanine to the porphyrin core with an excitation energy transfer quantum yield of 0.38.

Spectroscopic study of electron and energy transfer in novel silicon phthalocyanine--boron dipyrromethene triads.

Phthalocyanines (Pcs) and boron dipyrromethenes (BDPs) are two versatile classes of functional dyes suitable for design of artificial light harvesting and charge separation systems. In the present work, we report the results of photophysical investigations of two novel non-sandwich-type BDP-Pc heterotriads, in which two BDP or mono-styryl BDP moieties are linked to the central atom of a silicon(iv) phthalocyanine core (triad 4 and 5, respectively). It was found that the photophysical properties of the triads in toluene and N,N-dimethylformamide (DMF) are strongly affected by two different types of interaction between the BDP and the Pc parts, namely excitation energy transfer (EET) and photoinduced charge transfer (CT).

Spectroscopic study of NH-tautomerism in novel cycloketo-tetraphenylporphyrins.

The NH-tautomerism is a fundamental property of all metal-free porphyrins. In the present study it was investigated for three novel nonsymmetrical cycloketo-tetraphenylporphyrins in isotropic solutions. The combination of steady-state absorption and fluorescence techniques with decay-associated fluorescence spectroscopy was demonstrated to be a powerful tool to bring into light the photophysical properties of individual NH-tautomers even at room temperature.

Switching the photo-induced energy and electron-transfer processes in BODIPY-phthalocyanine conjugates.

Two novel silicon(IV) phthalocyanines substituted axially with two BODIPY or mono-styryl BODIPY moieties have been synthesised, which exhibit predominantly a photo-induced energy or electron-transfer process in toluene depending on the axial substituents.

Annulated dinuclear metal-free and Zn(II) phthalocyanines: photophysical studies and quantum mechanical calculations.

The results of steady-state and time-resolved absorption and fluorescence experiments as well as quantum mechanical density functional theory (DFT) calculations of metal-free and Zn(II) mononuclear and dinuclear (sharing a common benzene ring) phthalocyanines are presented. A detailed comparison between measured and calculated absorption spectra of all compounds is done, showing a good agreement between theory and experiment. The NH tautomerization for phthalocyanines with an extended pi-electron system was shown for the first time at room temperature.

The first observation of 4f-luminescence in new heteronuclear lanthanide-germanium complexes.

New lanthanide-germanium complexes with diethylenetriaminepentaacetic acid (DTPA) have been synthesized and were characterized by means of elemental analysis, IR-, UV-absorption and luminescent spectroscopy. The 4f-luminescence of heteronuclear Ln(Ge-DTPA)2 (Ln=Sm, Eu, Tb, Dy) complexes in aqueous solutions was investigated for the first time.

The influence of solvent polarity and metalation on energy and electron transfer in porphyrin-phthalocyanine heterotrimers.

Heteroporphyrin and -phthalocyanine arrays represent an attractive class of light harvesters and charge-separation systems exhibiting an easy route of synthesis and high chemical stability. In the present work, we report the results of photophysical investigations of two novel non-sandwich-type porphyrin-phthalocyanine heterotriads, in which two meso-tetraphenylporphyrin rings (H2TPP or ZnTPP) are linked to the central silicon atom of a silicon(IV) phthalocyanine core. It was found that the photophysical properties of the triads (H2Tr and ZnTr) in N,N-dimethylformamide (DMF) and toluene are strongly affected by two different types of interaction between the porphyrin (P) and the phthalocyanine (Pc) parts, namely excitation energy transfer (EET) and photoinduced charge transfer.

Synthesis and in vitro testing of a pyropheophorbide-a-fullerene hexakis adduct immunoconjugate for photodynamic therapy.

The employment of carriers to enhance drug selectivity is one of the strategies to increase the efficacy and reduce the side effects of antitumor therapy. The concept of a modular carrier system (MCS) was developed to construct a complex drug having a high efficacy and selectivity. An MCS employs diverse units or modules: beside the therapeutic unit, an addressing unit (e.

Photoinduced energy and electron transfer processes in hexapyropheophorbide a- fullerene [C(60)] molecular systems.

The photophysical properties of the novel hexapyropheophorbide a (P6), and hexakis (pyropheophorbide a)-C60 (FP6) were studied and compared with those of hexakis (pyropheophorbide a)-fullerene [5:1] hexaadduct (FHP6). It was found that after light absorption the pyropheophorbide a molecules in all three compounds undergo very efficient energy transfer as well as partly excitonic interactions. The last process results in the formation of energy traps, which could be resolved experimentally.

Synthesis and photophysical properties of annulated dinuclear and trinuclear phthalocyanines.

Metal-free mononuclear, dinuclear and trinuclear phthalocyanines were prepared by a mixed cyclotetramerisation of a 1,2,4,5-tetracyanobenzene derivative and 4,5-bis(2,6-dimethylphenoxy)phthalonitrile. For the first time, a pi-electron-conjugated trinuclear phthalocyanine was synthesised with phthalocyanine units connected by common annulated benzene rings. The Q band of the trinuclear compound in solution occurs at lambda = 944 nm whereas those of the dinuclear and mononuclear compounds are at lambda = 853/830 and 701/664 nm, respectively.

Dissipation of electronic excitation energy within a C60 [6:0]-hexaadduct carrying 12 pyropheophorbide a moieties.

The synthesis and photophysical studies of a fullerene [6:0]-hexaadduct that carries 12 pyropheophorbide a units are reported. The synthesis started with the malonate 1, which was coupled under template conditions to C(60)() to give the hexaadduct 2. After removal of the protecting group with acid the dodecakis amino-substituted precursor compound 3 was generated.