Metal (M = Cr, Mo, W, Re) carbonyl complexes with porphyrin and carborane isocyanide ligands: light-induced oxidation and carbon oxide release for antitumor efficacy.

The tetrapyrrolic macrocycle as a scaffold for various chemical modifications provides broad opportunities for the preparation of complex multifunctional conjugates suitable for binary antitumor therapies. Typically, illumination with monochromatic light triggers the photochemical generation of reactive oxygen species (ROS) (photodynamic effect). However, more therapeutically valuable effects can be achieved upon photoactivation of tetrapyrrole derivatives.

Fast Reaction of the Prussian Blue Based Nanozyme "Artificial Peroxidase" with the Substrates: Pre-Steady-State Kinetic Approach.

This letter introduces the pre-steady-state kinetic approach, which is traditional for evaluation of elementary constants in molecular (enzyme) catalysis, for nanozymes. Apparently, the most active peroxidase-mimicking nanozyme based on catalytically synthesized Prussian Blue nanoparticles has been chosen. The elementary constants () for the nanozymes' reduction by an electron-donor substrate (being the fastest stage according to steady-state kinetic data) have been determined by means of stopped-flow spectroscopy.

Pharmaceutical Approach to Develop Novel Photosensitizer Nanoformulation: An Example of Design and Characterization Rationale of Chlorophyll α Derivative.

In this study, we described physico-chemical properties of novel nanoformulation of photosensitizer-pyropheophorbide α 17-diethylene glycol ester (XL) (chlorophyll α derivative), revealing insights into antitumor activity and maintaining quality, meeting the pharmaceutical approach of new nanoformulation design. Our formulation, based on poly(lactic-co-glycolic acid) (PLGA) nanoparticles, increased XL solubility and selective tumor-targeted accumulation. In our research, we revealed, for the first time, that XL binding to polyvinyl alcohol (PVA) enhances XL photophysical activity, providing the rationale for PVA application as a stabilizer for nanoformulations.

The effect of substituent position and solvent on thermal Z‒E isomerization of dihydroquinolylazotetrazole dyes: kinetic, thermodynamic, and spectral approaches.

Kinetic and thermodynamic parameters have been investigated for the thermal Z‒E isomerization of dihydroquinolylazotetrazole dyes with alkyl substituents (Me, t-Bu, and Adm) at positions 1 (dyes 2) and 2 (dyes 3) of the tetrazole moiety in two solvents of different polarity, acetonitrile (MeCN) and toluene. The experimental results show crucial dependence of these parameters on a substituent position in the tetrazole moiety and on a solvent. For dyes 2, E and ΔH are lower in MeCN than in toluene that results in a high increase in the lifetimes of the Z isomers: from milliseconds in MeCN to minutes in toluene.

Perfluorocarbon Nanoemulsions with Fluorous Chlorin-Type Photosensitizers for Antitumor Photodynamic Therapy in Hypoxia.

The efficacy of photodynamic therapy (PDT) strictly depends on the availability of molecular oxygen to trigger the light-induced generation of reactive species. Fluorocarbons have an increased ability to dissolve oxygen and are attractive tools for gas delivery. We synthesized three fluorous derivatives of chlorin with peripheral polyfluoroalkyl substituents.

Photoinduced Reduction of Novel Dual-Action Riboplatin Pt(IV) Prodrug.

Controlled photoreduction of Pt(IV) prodrugs is a challenging task due to the possibility of targeted light-controlled activation of anticancer agents without affecting healthy tissues. Also, a conjugation of photosensitizers and clinically used platinum drugs into one Pt(IV) prodrug allows combining photodynamic therapy and chemotherapy approaches into one molecule. Herein, we designed the cisplatin-based Pt(IV) prodrug Riboplatin with tetraacetylriboflavin in the axial position.

Fluorescent boron difluoride curcuminoides as perspective materials for bio-visualization.

Curcuminoids of boron difluoride, 1-aryl(hetaryl)-5-phenylpenta-2,4-dien-1-onates of boron difluoride, have been synthesized. A comparative study of the electronic structure, luminescent properties and their potential for applications in bio-imaging has been carried out. The influence of the electronic structure of α-substituents on the luminescence of compounds was studied by the methods of stationary and time-resolved luminescence spectroscopy and DFT modeling.

Benzylidene Cyclopentanone Derivative Photoinitiator for Two-Photon Photopolymerization-Photochemistry and 3D Structures Fabrication for X-ray Application.

Micron- and submicron-scale 3D structure realization nowadays is possible due to the two-photon photopolymerization (TPP) direct laser writing photolithography (DLW photolithography) method. However, the achievement of lithographic features with dimensions less than 100 nm is in demand for the fabrication of micro-optical elements with high curvature values, including X-ray microlenses. Spectroscopic and photochemical study of a photoinitiator (PI) based on a methyl methacrylate derivative of 2,5-bis(4-(dimethylamino)benzylidene) cyclopentanone was performed.

Characterization of a Novel Amphiphilic Cationic Chlorin Photosensitizer for Photodynamic Applications.

A novel amphiphilic cationic chlorin derivative was investigated as a promising photosensitizer for photodynamic therapy. Two cationic -N(CH) groups on the periphery of the macrocycle provide additional hydrophilization of the molecule and ensure its electrostatic binding to the mitochondrial membranes and bacterial cell walls. The presence of a hydrophobic phytol residue in the same molecule results in its increased affinity towards the phospholipid membranes while decreasing its stability towards aggregation in aqueous media.

Mechanistic aspects of the transamination reactions catalyzed by D-amino acid transaminase from Haliscomenobacter hydrossis.

Pyridoxal-5'-phosphate-(PLP-) dependent D-amino acid transaminases (DAATs) catalyze stereoselective reversible transfer of the amino group between D-amino acids and keto acids. In vivo DAATs are commonly known to synthesize D-glutamate for cell wall peptidoglycans. Today DAATs meet increasing attention for application in the synthesis of D-amino acids, whereas little is known about the mechanism of substrate recognition and catalytic steps of the D-amino acids conversion by DAATs.

Intramolecular photo-driven charge transfer in a series of pyridyl substituted phenyloxazoles. Structural relaxation in meta-substituted ethylpyridinium derivative of phenyloxazole.

A series of pyridyl (pyridinium) substituted benzoxazoles were studied by steady state absorption, fluorescence spectroscopy, time-resolved fluorescence spectroscopy, fs pulse absorption and polarization spectroscopy, and quantum-chemical calculations. The spectral and kinetic parameters of the fluorophores in MeCN and EtOAc were obtained experimentally and were calculated by means of DFT and TDDFT methods. A scheme including four transient excited states was proposed for the interpretation of differential absorption kinetics of the charged fluorophores.

Fluorescence characteristics of lipofuscin fluorophores from human retinal pigment epithelium.

Lipofuscin granules accumulate in the retinal pigment epithelium (RPE) with age, especially in patients with visual diseases, including progressive age-related macular degeneration (AMD). Bisretinoids and their photooxidation and photodegradation products are major sources of lipofuscin granule fluorescence. The present study focused on examining the fluorescence decay characteristics of bisretinoid photooxidation and photodegradation products to evaluate the connection between fluorescence lifetime and spectral characteristics of target fluorophore groups.

DNA sequence-specific ligands. XVIII. Synthesis, physico-chemical properties; genetic, virological, and biochemical studies of fluorescent dimeric bisbenzimidazoles DBPA(n).

A set of AT-specific fluorescent dimeric bisbenzimidazoles DBPA(n) with linkers of different lengths bound to DNA in the minor groove were synthesized and their genetic, virological, and biochemical studies were performed. The DBPA(n) were shown to be effective inhibitors of the histon-like protein H-NS, a regulator of the DNA transcription factor, as well as of the Aliivibrio logei Quorum Sensing regulatory system in E. coli cells.

Photoactivated biscarbocyanine dye with two conjugated chromophores: complexes with albumin, photochemical and phototoxic properties.

Complexes of photosensitizers with blood proteins play an essential role in their delivery to the cell, as well as in the efficacy of photodynamic therapy. Biscarbocyanine dye non-covalently binds human serum albumin (HSA), the dissociation constant of the dye with albumin being Kd = (1.7 ± 0.

Complex formation of albumin with tricarbocyanine dyes containing phosphonate groups.

The spectral characteristics, binding constants with bovine (BSA) and human serum albumin (HSA) and lifetimes of fluorescence in PBS and EtOH solutions and in the presence of BSA in PBS were measured for novel indotricarbocyanine dyes bearing remote phosphonate groups. These parameters are close to those for indocyanine green (ICG) indicating that the Coulomb interaction does not play a significant role in complex formation, and the binding is determined by the interaction of the dye polymethine chain with albumin. The fluorescence lifetimes of the complexes with BSA strongly indicate the formation of complexes of two types with different lifetimes.