Effect of novel porphyrazine photosensitizers on normal and tumor brain cells

Photodynamic therapy (PDT) is a clinically approved procedure for targeting tumor cells. Though several different photosensitizers have been developed, there is still much demand for novel photosensitizers with improved properties. In this study we aim to characterize the accumulation, localization and dark cytotoxicity of the novel photosensitizers developed in-house derivatives of porphyrazines (pz I-IV) in primary murine neuronal cells, as well as to identify the concentrations at which pz still effectively induces death in glioma cells yet is nontoxic to nontransformed cells. The study shows that incubation of primary neuronal and glioma cells with pz I-IV leads to their accumulation in both types of cells, but their rates of internalization, subcellular localization and dark toxicity differ significantly. Pz II was the most promising photosensitizer. It efficiently killed glioma cells while remaining nontoxic to primary neuronal cells. This opens up the possibility of evaluating pz II for experimental PDT for glioma

Novel Tetraaryltetracyanoporphyrazine Vanadyl Complexes with Enhanced Electron Withdrawing Properties

International audienc

Reaction of Sodium with Phenyltrichlorosilane

Original Russian Text: V.V. Semenov, A.Yu. Nerovnya, V.A. Egorov, N.F. Cherepennikova, L.G. Klapshina, A.I. Kirillov, T.I. Lopatina, W.E. Douglas, G.A. Domrachev, 2006, published in Doklady Akademii Nauk, 2006, Vol. 407, No. 4, pp. 489–492.International audienc

Organometallic self-organized nanomaterials for nonlinear optics

International audienceNovel nonlinear optical polymeric film-producing nanocomposites based on bis(arene)chromium complexes incorporated into a CN-containing matrix have been developed. Polymer-precursors were prepared by the reaction of Cr(EtnC6H6?n)2 mixtures (n = 1,2,3) with CN-containing vinyl monomers (acrylonitrile, crotononitrile and ethylcyanoacrylate). The nonlinear-optical measurements in the absence of external electrical fields showed a "natural" anisotropy resulting from self-organization taking place during the film formation process. Measurements by the spectrally-resolved two-beam coupling method confirmed that the test composites exhibited a significant cubic nonlinear optical susceptibility of the ultra-fast electronic type

Unraveling of functional activity of primary hippocampal neuron-glial networks in photodynamic therapy based on tetracyanotetra(aryl)porphyrazines

The current efforts in photodynamic therapy (PDT) of brain cancer are focused on the development of novel photosensitizers with improved photodynamic properties, targeted specific localization, and sensitivity to the irradiation dose, ensuring the effectiveness of PDT with fewer side effects for normal nerve tissue. Here, we characterize the effects of four photosensitizers of the tetracyanotetra(aryl)porphyrazine group (pz I-IV) on the functional activity of neuron-glial networks in primary hippocampal cultures in their application in normal conditions and under PDT. The data revealed that the application of pz I-IV leads to a significant decrease in the main parameters of the functional calcium activity of neuron-glial networks and pronounced changes in the network characteristics. The observed negative effects of pz I-IV were aggravated under PDT. Considering the significant restructuring of the functional architectonics of neuron-glial networks that can lead to severe impairments in synaptic transmission and loss of brain functions, and the feasibility of direct application of PDT based on pz I-IV in the therapy of brain tumors is highly controversial. Nevertheless, the unique properties of pz I-IV retain a great prospect of their use in the therapy of tumors of another origin and cellular metabolism

Solution DFWM chi((3)) non-linear optical properties of poly[(arylene)silylene]s and poly[(arylene)(ethynylene)silylene]s containing tetra- or hypercoordinate silicon

The third-order optical nonlinearities of a series of conjugated poly[(arylene)(ethynylene)silylene]s, and also of a complementary series of poly[(arylene)silylene] statistical copolymers without acetylene groups, have been studied in chloroform solution by using the degenerate four-wave mixing technique with a Q-switched Nd:YAG laser-oscillator at 1064 nm and a pulse duration of ca. 6 ns. The polymers contain a variety of arylene groups including carbazole and anthracene. The electronic and nuclear contributions of the chi((3)) susceptibility and the thermal nonlinearity of the solutions were separated. The chi((3)) susceptibilities of some poly[(arylene)(ethynylene)silylene]s were found to be as high as \Re chi((3))\=0.95x10(-10) esu for solutions of concentration 50 g l(-1). The results show that the presence of a single 8-(dimethylamino)naphthyl ligand at silicon affording pentacoordination has a beneficial effect on the chi((3)) properties. Comparison of the results for the poly[(arylene)silylene]s with those for the poly[(arylene)(ethynylene)silylene]s suggests that the absence of acetylene groups in the former case has in general a deleterious effect on the chi((3)) properties. Confirmation of the order of magnitude of the non-linear response has been confirmed by Z-scan measurements with picosecond laser pulses on hybrid sol-gel silica films of two of the poly[(arylene)(ethynylene)silylene]s containing arylene amide groups

Chromium-containing organometallic nanomaterials for non-linear optics

International audienceNovel nonlinear optical polymeric film-producing nanocomposites based on bis(arene)chromium complexes incorporated into a CN-containing matrix have been developed. Polymer-precursors were prepared by the reaction of Cr(EtnC6H6 n)2 (n = 1,2,3) with CN-containing vinyl monomers (acrylonitrile, crotononitrile or ethyl 2-cyanopropenoate). Extraordinarily high third-order nonlinear optical susceptibilities of the ultra-fast electronic type have been demonstrated at various wavelengths for polymer films prepared from these composites by using the Z-scan technique and the spectrally-resolved two-beam coupling method. A notable electro-optical response of the composite with an essential contribution of orientational effects was established. The electron-diffraction pattern in films and the presence of a non-zero electro-optical coefficient in the absence of an external poling field indicates the formation of self-organized structures. In CrPAN and [CrPAN]+TCNE–, a single Cr-C distance was found in the EXAFS data refinement, showing that the arene rings are parallel and symmetric as in bis(benzene)chromium. The Cr-C distances in these two materials are very similar to the 2.13 Angstroms in bis(benzene)chromium. In [CrPAN]+OH–, more than one metal-carbon distance was resolved, showing either that the two arene rings are at different distances from the metal, or that they are tilted rather than parallel

Synthesis and thermal transformations of polyphosphosiloxane based on trimethyl phosphate and (3-aminopropyl)triethoxysilane

International audienceA method for the synthesis of polyphosphosiloxane by the thermal condensation of an equimolar mixture of trimethyl phosphate and (3-aminopropyl)triethoxysilane at 200 °C was developed. The reaction affords ethanol and polyphosphosiloxane-{Si(OEt)[(CH2)3NR1R2]-O-P(O)(OMe)-O}n-(R1 = H, Me; R2 = Me), whose composition and structure were confirmed by 1H, 13C, and 31P NMR spectroscopy, IR spectroscopy, and elemental analysis. The scheme of polymerization involving the intermediate formation of methyl-and dimethylphosphoric acids and their condensation with ethoxysilanes was proposed. The calcination of the obtained polyphosphosiloxane in vacuo at 350 °C results in the elimination of the amino groups and alkoxide substituents, and a spatially cross-linked polymer is formed as an amorphous powder. Its further thermolysis at 600 and 1000 °C gives crystalline phosphosilicates Si5O(PO4)6 or SiP2O7. Their amorphous and crystalline samples were characterized by IR spectroscopy, X-ray diffraction analysis, and solid-state 13C and 31P spectroscopy

Cyanoarylporphyrazines with high viscosity sensitivity : a step towards dosimetry-assisted photodynamic cancer treatment

Despite the significant relevance of photodynamic therapy (PDT) as an efficient strategy for primary and adjuvant anticancer treatment, several challenges compromise its efficiency. In order to develop an "ideal photosensitizer" and the requirements applied to photosensitizers for PDT, there is still a need for new photodynamic agents with improved photophysical and photobiological properties. In this study, we performed a detailed characterization of two tetracyanotetra(aryl)porphyrazine dyes with 4-biphenyl (pz II) and 4-diethylaminophenyl (pz IV) groups in the periphery of the porphyrazine macrocycle. Photophysical properties, namely, fluorescence quantum yield and lifetime of both photosensitizers, demonstrate extremely high dependence on the viscosity of the environment, which enables them to be used as viscosity sensors. Pz II and pz IV easily enter cancer cells and efficiently induce cell death under light irradiation. Using fluorescence lifetime imaging microscopy, we demonstrated the possibility of assessing local intracellular viscosity and visualizing viscosity changes driven by PDT treatment with the compounds. Thus, pz II and pz IV combine the features of potent photodynamic agents and viscosity sensors. These data suggest that the unique properties of the compounds provide a tool for PDT dosimetry and tailoring the PDT treatment regimen to the individual characteristics of each patient