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1.
Phys Chem Chem Phys ; 23(24): 13760-13767, 2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-34132295

RESUMO

A novel rotary switch, overcoming the disadvantages of hydrazone based switches with competitive proton acceptor sub-rotors, has been designed. The new compound contains a pyridyl ring and a COOH group as sub-rotors, which provides engagement of the pyridyl nitrogen atom and leads to the existence of a single isomer in the ground state. The availability of acidic functionality in the rotor creates conditions for excited state intramolecular proton transfer (ESIPT), which exhibits anti-Kasha behavior.

2.
Photochem Photobiol ; 97(4): 710-717, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33393108

RESUMO

Fluorescent and computational methods were used to elucidate the binding expedient of 2-carbamido-1,3-indandione (CAID) tautomers to nucleotides. The dependence of the fluorescence emission of CAID loaded nucleic acids sequences to compound concentration, temperature and time variation was investigated. It was found that the subject compound binds to nucleic acids but does not intercalate. According to our quantum-chemical calculations on the conjugation between CAID and nucleotides, the binding in the formed complexes may be through hydrogen bonds. Two possible types of complexes were considered-CAID to the phosphate group and CAID to the nucleobase. To estimate the binding affinity, the interaction energies of the formed complexes were calculated. Tautomer 2-carboamide-1-hydroxy-3-oxo-indane is preferred in the formation of complexes, and the phosphate group complexes were more stable. Generally, the guanosine and deoxyguanosine monophosphate complexes were the most preferred regardless of the complex type. Because of the lack of cytotoxic effect on untransformed cell lines of mouse embryo fibroblasts Balb/c 3T3 according to our previous report (Markova et al, (2017) Bulg Chem Commun, 49D, 221-226) and the affinity to nucleic acids, we can suggest that the subject compound could be suitable to be used as a novel type of fluorescent biomarker.

3.
J Biomol Struct Dyn ; 39(15): 5563-5578, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32677584

RESUMO

Abiotic synthesis of nucleobases and amino acids is of critical importance as it sheds light on potential prebiotic chemical reactions. During thermal decomposition of formamide in vacuum conditions, purine, cytosine, adenine, hypoxanthine, uracil, pterin, urea, urocanic acid, glycine, alanine and norvaline were detected. The compounds were obtained without catalyst by heating at 100-180 °C or microwave heating of formamide. Reaction network of self-catalyzed chemical reactions is suggested, showing how from only one parent molecule, nucleobases, urea and the amino acid glycine can be produced. The reaction pathways are theoretically determined using SCS-MP2 calculations.Communicated by Ramaswamy H. Sarma.

4.
Biochim Biophys Acta Gen Subj ; 1865(1): 129773, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33132199

RESUMO

BACKGROUND: Quinazolines 1 to 6, with an aromatic or aryl-vinyl substituent in position 2 are selected with the aim to compare their structures and biological activity. The selection includes a natural alkaloid, schizocommunin, and the synthetic 2-(2'-quinolyl)-3H-quinazolin-4-one, known to interact with guanine-quadruplex dependent enzymes, respectively telomerase and topoisomerase. METHODS: Breast cancer cells of the MDA cell line have been used to study the bioactivity of the tested compounds by the method of Comet Assay and FACS analyses. We model observed effects assuming stacking interactions of studied heterocycles with a naked skeleton of G-quadruplex, consisting of guanine quartet layers and potassium ions. Interaction energies are computed using a dispersion corrected density functional theory method, and an electron-correlated molecular orbital theory method. RESULTS: Selected compounds do not remarkably delay nor change the dynamics of cellular progression through the cell cycle phases, while changing significantly cell morphology. Our computational models quantify structural effects on heterocyclic G4-complex stabilization energies, which directly correlate with observed biological activity. CONCLUSION: Our computational model of G-quadruplexes is an acceptable tool for the study of interaction energies of G-quadruplexes and heterocyclic ligands, predicting, and allowing design of novel structures. GENERAL SIGNIFICANCE: Genotoxicity of quinazolin-4-one analogues on human breast cancer cells is not related to molecular metabolism but rather to their interference with G-quadruplex regulatory mechanisms. Computed stabilization energies of heterocyclic ligand complexes of G-quadruplexes might be useful in the prediction of novel telomerase / helicase, topoisomerase and NA polymerase dependent drugs.


Assuntos
Quadruplex G/efeitos dos fármacos , Quinazolinas/química , Quinazolinas/farmacologia , Linhagem Celular Tumoral , Desenho de Fármacos , Descoberta de Drogas , Humanos , Indóis/química , Indóis/farmacologia , Modelos Moleculares , Quinazolinonas/química , Quinazolinonas/farmacologia , Telômero/química
5.
Sensors (Basel) ; 20(19)2020 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-33003353

RESUMO

Immobilization of proteins on a surface plasmon resonance (SPR) transducer is a delicate procedure since loss of protein bioactivity can occur upon contact with the untreated metal surface. Solution to the problem is the use of an immobilization matrix having a complex structure. However, this is at the expense of biosensor selectivity and sensitivity. It has been shown that the matrix-assisted pulsed laser evaporation (MAPLE) method has been successfully applied for direct immobilization (without a built-in matrix) of proteins, preserving their bioactivity. So far, MAPLE deposition has not been performed on a gold surface as required for SPR biosensors. In this paper we study the impact of direct immobilization of heme proteins (hemoglobin (Hb) and myoglobin (Mb)) on their bioactivity. For the purpose, Hb and Mb were directly immobilized by MAPLE technique on a SPR transducer. The bioactivity of the ligands immobilized in the above-mentioned way was assessed by SPR registration of the molecular reactions of various Hb/Mb functional groups. By SPR we studied the reaction between the beta chain of the Hb molecule and glucose, which shows the structural integrity of the immobilized Hb. A supplementary study of films deposited by FTIR and AFM was provided. The experimental facts showed that direct immobilization of an intact molecule was achieved.


Assuntos
Técnicas Biossensoriais , Hemoglobinas/análise , Proteínas Imobilizadas/análise , Mioglobina/análise , Ressonância de Plasmônio de Superfície , Ouro
6.
Molecules ; 25(1)2019 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-31881750

RESUMO

The development of ionic liquids based on active pharmaceutical ingredients (API-ILs) is a possible solution to some of the problems of solid and/or hydrophobic drugs such as low solubility and bioavailability, polymorphism and an alternative route of administration could be suggested as compared to the classical drug. Here, we report for the first time the synthesis and detailed characterization of a series of ILs containing a cation amino acid esters and anion ketoprofen (KETO-ILs). The affinity and the binding mode of the KETO-ILs to bovine serum albumin (BSA) were assessed using fluorescence spectroscopy. All compounds bind in a distance not longer than 6.14 nm to the BSA fluorophores. The estimated binding constants (KA) are in order of 105 L mol-1, which is indicative of strong drug or IL-BSA interactions. With respect to the ketoprofen-BSA system, a stronger affinity of the ILs containing l-LeuOEt, l-ValOBu, and l-ValOEt cation towards BSA is clearly seen. Fourier transformed infrared spectroscopy experiments have shown that all studied compounds induced a rearrangement of the protein molecule upon binding, which is consistent with the suggested static mechanism of BSA fluorescence quenching and formation of complexes between BSA and the drugs. All tested compounds were safe for macrophages.


Assuntos
Líquidos Iônicos/síntese química , Líquidos Iônicos/metabolismo , Cetoprofeno/síntese química , Soroalbumina Bovina/metabolismo , Animais , Bovinos , Morte Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ésteres/síntese química , Ésteres/química , Transferência Ressonante de Energia de Fluorescência , Líquidos Iônicos/química , Líquidos Iônicos/toxicidade , Cetoprofeno/química , Cetoprofeno/toxicidade , Cinética , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Camundongos , Estrutura Secundária de Proteína , Células RAW 264.7 , Soroalbumina Bovina/química , Solubilidade , Solventes/química , Água/química
7.
Biomed Opt Express ; 10(8): 4115-4125, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31452998

RESUMO

Using an original model of stress-induced colon adenocarcinoma, we uncover atypical vasorelaxation effects of a mucosa injection of epinephrine assessed by laser speckle contrast imaging and a significant increase of fluorescent intensity of 5-ALA/PpIX from malignant colon tissues by a mucosa injection of nitroglycerine. We clearly demonstrate a high activity of adrenergic and nitrergic mechanisms underlying this phenomenon and discuss their application in improving of optical approaches for effective diagnosis of gastrointestinal cancer.

8.
Z Naturforsch C J Biosci ; 74(7-8): 183-191, 2019 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-31194695

RESUMO

The photodynamic impact of water-soluble zwitterionic zinc phthalocyanines (ZnPc1-4) was studied on pathogenic bacterial strains after specific light exposure (LED 665 nm). The structural differences between the studied ZnPc1-4 are in the positions and the numbers of substitution groups as well as in the bridging atoms (sulfur or oxygen) between substituents and macrocycle. The three peripherally substituted compounds (ZnPc1-3) are tetra-2-(N-propanesulfonic acid)oxypyridine (ZnPc1), tetra-2-(N-propanesulfonic acid)mercaptopyridine (ZnPc2), and octa-substituted 2-(N-propanesulfonic acid)mercaptopyridine (ZnPc3). The nonperipherally substituted compound is tetra-2-(N-propanesulfonic acid)mercaptopyridine (ZnPc4). The uptake and localization capability are studied on Gram (+) Enterococcus faecalis and Gram (-) Pseudomonas aeruginosa as suspensions and as 48 h biofilms. Relatively high accumulations of ZnPc1-4 show bacteria in suspensions with different cell density. The compounds have complete penetration in E. faecalis biofilms but with nonhomogenous distribution in P. aeruginosa biomass. The cytotoxicity test (Balb/c 3T3 Neutral Red Uptake) with ZnPc1-4 suggests the lack of dark toxicity on normal cells. However, only ZnPc3 has a minimal photocytotoxic effect toward Balb/c 3T3 cells and a comparable high potential in the photoinactivation of pathogenic bacterial species.


Assuntos
Anti-Infecciosos/farmacologia , Enterococcus faecalis/efeitos dos fármacos , Indóis/química , Compostos Organometálicos/química , Pseudomonas aeruginosa/efeitos dos fármacos , Zinco/química , Anti-Infecciosos/química
9.
Z Naturforsch C J Biosci ; 73(5-6): 221-228, 2018 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-29306935

RESUMO

Photodynamic inactivation (PDI) has been featured as an effective strategy in the treatment of acute drug-resistant infections. The efficiency of PDI was evaluated against three periodontal pathogenic bacteria that were tested as drug-resistant strains. In vitro studies were performed with four water-soluble cationic Zn(II) phthalocyanines (ZnPc1-4) and irradiation of a specific light source (light-emitting diode, 665 nm) with three doses (15, 36 and 60 J/cm2). The well detectable fluorescence of ZnPcs allowed the cellular imaging, which suggested relatively high uptakes of ZnPcs into bacterial species. Complete photoinactivation was achieved with all studied ZnPc1-4 for Enterococcus faecalis (E. faecalis) at a light dose of 15 J/cm2. The photodynamic response was high for Prevotella intermedia (P. intermedia) after the application of 6 µM of ZnPc1 and a light dose of 36 J/cm2 and for 6 µM of ZnPc2 at 60 J/cm2. P. intermedia was inactivated with ZnPc3 (4 log) and ZnPc4 (2 log) with irradiation at an optimal dose of 60 J/cm2. Similar photoinactivation results (2 log) were achieved for Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) treated with 6 µM ZnPc1 and ZnPc2 at a light dose of 60 J/cm2. The study suggested that PDI with quaternized Zn(II) phthalocyanines and specific light irradiation appears to be a very useful antimicrobial strategy for effective inactivation of drug-resistant periodontal pathogens.


Assuntos
Antibacterianos/farmacologia , Indóis/farmacologia , Compostos Organometálicos/farmacologia , Doenças Periodontais/microbiologia , Fármacos Fotossensibilizantes/farmacologia , Aggregatibacter actinomycetemcomitans/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Farmacorresistência Bacteriana/efeitos dos fármacos , Enterococcus faecalis/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Doenças Periodontais/tratamento farmacológico , Prevotella intermedia/efeitos dos fármacos
10.
Biomed Opt Express ; 8(11): 5040-5048, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-29188101

RESUMO

Photodynamic treatment (PDT) causes a significant increase in the permeability of the blood-brain barrier (BBB) in healthy mice. Using different doses of laser radiation (635 nm, 10-40 J/cm2) and photosensitizer (5-aminolevulinic acid - 5-ALA, 20 and 80 mg/kg, i.v.), we found that the optimal PDT for the reversible opening of the BBB is 15 J/cm2 and 5-ALA, 20 mg/kg, exhibiting brain tissues recovery 3 days after PDT. Further increases in the laser radiation or 5-ALA doses have no amplifying effect on the BBB permeability, but are associated with severe damage of brain tissues. These results can be an informative platform for further studies of new strategies in brain drug delivery and for better understanding of mechanisms underlying cerebrovascular effects of PDT-related fluorescence guided resection of brain tumor.

11.
Z Naturforsch C J Biosci ; 72(3-4): 123-128, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-27845890

RESUMO

Various metal phthalocyanines have been studied for their capacity for photodynamic effects on viruses. Two newly synthesized water-soluble phthalocyanine Zn(II) complexes with different charges, cationic methylpyridyloxy-substituted Zn(II)- phthalocyanine (ZnPcMe) and anionic sulfophenoxy-substituted Zn(II)-phthalocyanine (ZnPcS), were used for photoinactivation of two DNA-containing enveloped viruses (herpes simplex virus type 1 and vaccinia virus), two RNA-containing enveloped viruses (bovine viral diarrhea virus and Newcastle disease virus) and two nude viruses (the enterovirus Coxsackie B1, a RNA-containing virus, and human adenovirus 5, a DNA virus). These two differently charged phthalocyanine complexes showed an identical marked virucidal effect against herpes simplex virus type 1, which was one and the same at an irradiation lasting 5 or 20 min (Δlog=3.0 and 4.0, respectively). Towards vaccinia virus this effect was lower, Δlog=1.8 under the effect of ZnPcMe and 2.0 for ZnPcS. Bovine viral diarrhea virus manifested a moderate sensitivity to ZnPcMe (Δlog=1.8) and a pronounced one to ZnPcS at 5- and 20-min irradiation (Δlog=5.8 and 5.3, respectively). The complexes were unable to inactivate Newcastle disease virus, Coxsackievirus B1 and human adenovirus type 5.


Assuntos
Complexos de Coordenação/síntese química , Indóis/síntese química , Fármacos Fotossensibilizantes/síntese química , Tolerância a Radiação/fisiologia , Inativação de Vírus , Zinco/química , Adenovírus Humanos/efeitos dos fármacos , Adenovírus Humanos/crescimento & desenvolvimento , Adenovírus Humanos/efeitos da radiação , Ânions , Cátions , Complexos de Coordenação/farmacologia , Vírus da Diarreia Viral Bovina Tipo 1/efeitos dos fármacos , Vírus da Diarreia Viral Bovina Tipo 1/crescimento & desenvolvimento , Vírus da Diarreia Viral Bovina Tipo 1/efeitos da radiação , Enterovirus Humano B/efeitos dos fármacos , Enterovirus Humano B/crescimento & desenvolvimento , Enterovirus Humano B/efeitos da radiação , Herpesvirus Humano 1/efeitos dos fármacos , Herpesvirus Humano 1/crescimento & desenvolvimento , Herpesvirus Humano 1/efeitos da radiação , Indóis/farmacologia , Lasers Semicondutores , Luz , Vírus da Doença de Newcastle/efeitos dos fármacos , Vírus da Doença de Newcastle/crescimento & desenvolvimento , Vírus da Doença de Newcastle/efeitos da radiação , Fármacos Fotossensibilizantes/farmacologia , Especificidade da Espécie , Eletricidade Estática , Vírus Vaccinia/efeitos dos fármacos , Vírus Vaccinia/crescimento & desenvolvimento , Vírus Vaccinia/efeitos da radiação
12.
Lasers Med Sci ; 31(8): 1591-1598, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27422105

RESUMO

Photodynamic inactivation (PDI) is a light-associated therapeutic approach suitable for treatment of local acute infections. The method is based on specific light-activated compound which by specific irradiation and in the presence of molecular oxygen produced molecular singlet oxygen and other reactive oxygen species, all toxic for pathogenic microbial cells. The study presents photodynamic impact of two recently synthesized water-soluble cationic lutetium (III) acetate phthalocyanines (LuPc-5 and LuPc-6) towards two pathogenic strains, namely, the Gram-negative bacterium Pseudomonas aeruginosa and a fungus Candida albicans. The photodynamic effect was evaluated for the cells in suspensions and organized in 48-h developed biofilms. The relatively high levels of uptakes of LuPc-5 and LuPc-6 were determined for fungal cells compared to bacterial cells. The penetration depths and distribution of both LuPcs into microbial biofilms were investigated by means of confocal fluorescence microscopy. The photoinactivation efficiency was studied for a wide concentration range (0.85-30 µM) of LuPc-5 and LuPc-6 at a light dose of 50 J cm-2 from red light-emitting diode (LED; 665 nm). The PDI study on microbial biofilms showed incomplete photoinactivation (<3 logs) for the used gentle drug-light protocol.


Assuntos
Anti-Infecciosos/farmacologia , Biofilmes/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Indóis/farmacologia , Fármacos Fotossensibilizantes/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Acetatos/química , Acetatos/farmacologia , Anti-Infecciosos/metabolismo , Indóis/metabolismo , Lasers Semicondutores , Lutécio/química , Lutécio/farmacologia , Testes de Sensibilidade Microbiana , Viabilidade Microbiana , Fármacos Fotossensibilizantes/metabolismo
13.
Photodiagnosis Photodyn Ther ; 14: 98-103, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26940846

RESUMO

BACKGROUND: The development of new water-soluble photosensitizers for photodynamic therapy (PDT) applications is a very active research topic. Efforts have been made to obtain the far-red absorbing phthalocyanine complexes with molecular design that facilitates the uptake and selectivity for a high PDT efficiency. METHODS: The monomolecular lutetium(III) acetate phthalocyanines (LuPcs) substituted with methylpyridyloxy groups at non-peripheral (5) and peripheral (6) positions were synthesized by following the modification of the well-known synthetical routes. The photo-physicochemical properties of the both quaternized LuPcs were evaluated by the steady-state and time-resolved spectroscopy. The photochemical technique was applied to study the generation of the singlet oxygen. RESULTS: Two water-soluble and cationic LuPcs were synthesized and chemically characterized. The photo-physicochemical properties of absorption (675 and 685nm) and the red shifted fluorescence (704 and 721nm) as well as the fluorescence lifetimes (2.24 and 3.27ns) were studied. The promising values of singlet oxygen quantum yields (0.32 for 5 and 0.35 for 6) were determined. CONCLUSIONS: Lutetium(III) acetate phthalocyanine complexes were synthesized and evaluated with physicochemical properties suitable for future photodynamic therapy applications.


Assuntos
Indóis/síntese química , Indóis/uso terapêutico , Lutécio , Fotoquimioterapia , Indóis/química , Lutécio/química , Lutécio/uso terapêutico , Estrutura Molecular , Solubilidade , Água/química
14.
J Fluoresc ; 25(6): 1601-14, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26342735

RESUMO

The present work reports theoretical and experimental studies on the photophysical properties of two tautomeric forms of 2-carbamido-1,3-indandione (CAID). By means of UV-vis, steady-state and time-dependent fluorescence spectroscopy it is shown that both enol forms, 2-(hydroxylaminomethylidene)-indan-1,3-dione and 2-carboamide-1-hydroxy-3-oxo-indan, coexist in solution. On the base of spectroscopic studies of CAID interaction with human serum albumin and DNA sequences, it was shown that the compound has potential and it is suitable for use as fluorescent molecular probe for investigation of different biomolecules. CAID shows relatively high photostability within 3 h irradiation period. Such behavior of the investigated compound supposes possibilities for using of the CAID molecule as sunscreen because of strong absorption in UVA, UVB and UVC light spectra.

15.
J Sci Food Agric ; 95(14): 2901-7, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25445203

RESUMO

BACKGROUND: Thymol (2-isopropyl-5-methylphenol) is the main monoterpene phenol found in thyme essential oil. This compound has revealed several biological properties, including antibacterial, anti-inflammatory and antioxidant activities. In this work, a comparison was made between the performance of different green solvents (ethanol, limonene and ethyl lactate), by pressurized liquid extraction (PLE) and supercritical fluid extraction (SFE) at different conditions, to extract thymol from three different varieties of thyme (Thymus vulgaris, Thymus zygis and Thymus citriodorus). Additionally, new solubility data of thymol in limonene and ethanol at ambient pressure and temperatures in the range 30-43 °C are reported. RESULTS: The highest thymol recoveries were attained with T. vulgaris (7-11 mg g(-1)). No thymol could be quantified in the PLE samples of T. citriodorus. The highest concentrations of thymol in the extracts were obtained with limonene. Thymol is very soluble in both solvents, particularly in ethanol (∼900 mg g(-1) at ∼40 °C), and is the main compound (in terms of peak area) present in the essential oil extracts obtained. CONCLUSION: The three solvents show good capacity to extract thymol from T. vulgaris and T. zygis by PLE. Although PLE proved to be a suitable technology to extract thymol from thyme plants, the highest concentrations of thymol were obtained by SFE with supercritical CO2 .


Assuntos
Cicloexenos/química , Etanol/química , Lactatos/química , Óleos Voláteis/química , Solventes/química , Terpenos/química , Timol/isolamento & purificação , Thymus (Planta)/química , Cromatografia com Fluido Supercrítico , Limoneno , Extratos Vegetais/química , Pressão , Solubilidade , Especificidade da Espécie , Timol/química , Thymus (Planta)/genética
16.
Photochem Photobiol ; 90(3): 628-40, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24164211

RESUMO

The Gram-negative Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum are major causative agents of aggressive periodontal disease. Due to increase in the number of antibiotic-resistant bacteria, antimicrobial Photodynamic therapy (aPDT) seems to be a plausible alternative. In this work, photosensitization was performed on Gram-positive and Gram-negative bacteria in pure culture using new-age cationic porphyrins, namely mesoimidazolium-substituted porphyrin derivative (ImP) and pyridinium-substituted porphyrin derivative (PyP). The photophysical properties of both the sensitizers including absorption, fluorescence emission, quantum yields of the triplet excited states and singlet oxygen generation efficiencies were evaluated in the context of aPDT application. The studied porphyrins exhibited high ability to accumulate into bacterial cells with complete penetration into early stage biofilms. As compared with ImP, PyP was found to be more effective for photoinactivation of bacterial strains associated with periodontitis, without any signs of dark toxicity, owing to its high photocytotoxicity.


Assuntos
Bactérias Gram-Negativas/isolamento & purificação , Bactérias Gram-Positivas/isolamento & purificação , Periodonto/microbiologia , Fotoquimioterapia , Fármacos Fotossensibilizantes/farmacologia , Porfirinas/farmacologia , Cátions , Espectroscopia de Ressonância Magnética , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
17.
Opt Express ; 21(25): 31453-61, 2013 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-24514719

RESUMO

Multilayer coatings composed of TiO(2), Ta(2)O(5), HfO(2), or Al(2)O(3) as high-index materials and SiO(2) as low-index material were investigated for laser-induced damage using 1 ps, 5 µJ pulses generated by a mode-locked Yb:YAG thin-disk oscillator operating at a wavelength of 1030 nm and repetition rate of 11.5 MHz. Previously reported linear band gap dependence of damage threshold at kHz repetition rates was confirmed also for the MHz regime. Additionally, we studied the effect of electric field distribution inside of the layer stack. We did not observe any significant influence of thermal effects on the laser-induced damage threshold in this regime.

18.
Eur J Med Chem ; 46(9): 4430-40, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21816518

RESUMO

Water-soluble phthalocyanine complexes of silicon (SiPc1) and germanium (GePc1) were synthesized. The absorbance of SiPc1 in water was with minor aggregation while GePc1 strongly aggregated in water. The fluorescence data in water showed low quantum yields of 0.073 (SiPc1) and 0.01 (GePc1) and similar lifetimes of 4.07 ns and 4.27 ns. The uptake of SiPc1 into Candida albicans cells was two orders of magnitude lower as compared to GePc1 and for both was dependent on the cell density. Fungal cells in suspension were completely inactivated after SiPc1 (1.8 µM) at soft light radiation (50 J cm(-2), 60 mW cm(-2)). The fungal biofilm formed on denture acrylic resin was inactivated with 3 log after fractionated light irradiation.


Assuntos
Biofilmes , Candida albicans/efeitos dos fármacos , Geranium/química , Indóis/farmacologia , Fotoquimioterapia , Fármacos Fotossensibilizantes/farmacologia , Silício/química , Indóis/química , Microscopia Confocal , Fármacos Fotossensibilizantes/química , Solubilidade , Espectrometria de Fluorescência , Espectrofotometria Infravermelho
19.
Photochem Photobiol Sci ; 10(1): 91-102, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21031201

RESUMO

Visible light-absorbing cationic water-soluble gallium(III) phthalocyanines (GaPcs) peripherally substituted with four and eight methylpyridyloxy groups were synthesized and investigated as antimicrobial photodynamic sensitizers. The inserted large gallium ion in the phthalocyanine ligand is axially substituted by one hydroxyl group which prevents aggregation of the complexes in aqueous solution. The cellular uptake and the photodynamic activity for the representative strains of the Gram positive bacteria methicillin-resistant Staphylococcus aureus(MRSA) and Enterococcus faecalis, of the Gram negative bacterium Pseudomonas aeruginosa and of the fungus Candida albicans in planktonic phase were studied. The tetra-methylpyridyloxy substituted GaPc1 showed lower cellular uptake compared to the octa-methylpyridyloxy substituted GaPc2. The photodynamic activity of the GaPcs was studied in comparison to methylene blue (MB) and a photodynamically active Zn(II)-phthalocyanine with the same substitution (ZnPcMe). Photodynamic treatment with 3.0 µM GaPc1 at mild light conditions (50 J cm(-2), 60 mW cm(-2)) resulted in a high photoinactivation of the microorganisms in the planktonic phase nevertheless the dark toxicity of GaPc1 towards MRSA and E. faecalis. GaPcs against fungal biofilm grown on polymethylmethacrylate (PMMC) resin showed a complete inactivation at a higher concentration of GaPc2 (6.0 µM) and of the referent sensitizer ZnPcMe. However, the bacterial biofilms were not susceptible to treatment of GaPcs with only 1-2 log reduction of the biofilm. The bacterial biofilm E. faecalis was effectively inactivated only with MB. The water-soluble octa-methylpyridyloxy substituted GaPc2 has a potential value for photodynamic treatment of C. albicans biofilms formed on denture acrylic resin.


Assuntos
Biofilmes/efeitos dos fármacos , Complexos de Coordenação/química , Gálio/química , Indóis/química , Fármacos Fotossensibilizantes/química , Plâncton/efeitos dos fármacos , Animais , Biofilmes/efeitos da radiação , Candida albicans/efeitos dos fármacos , Bovinos , Linhagem Celular , Embrião de Galinha , Chlorocebus aethiops , Complexos de Coordenação/síntese química , Complexos de Coordenação/toxicidade , Cães , Enterococcus/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Fármacos Fotossensibilizantes/síntese química , Fármacos Fotossensibilizantes/toxicidade , Plâncton/efeitos da radiação , Pseudomonas aeruginosa/efeitos dos fármacos , Espectrometria de Fluorescência
20.
FEMS Microbiol Lett ; 294(2): 133-40, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19431233

RESUMO

Antibacterial photodynamic therapy is a pioneering method for the inactivation of pathogenic bacteria. Four tetra alkyl-substituted cationic phthalocyanines with different hydrocarbon chains attached to the pyridyloxy group were synthesized. These photodynamic sensitizers were studied for antibacterial inactivation of a multidrug-resistant strain of Gram-negative bacterium Aeromonas hydrophila. Aeromonas species are recognized as etiological agents of a wide spectrum of diseases in humans and animals. The uptake of phthalocyanines by the bacterial cells decreased with an increase in cell density. Following the phthalocyanine solubility from hydrophilic to hydrophobic complexes, the accumulation capacity increased. Full inactivation was achieved with phthalocyanine with (methoxy) pyridyloxy substitution following a short exposure time, low drug concentration and mild irradiation. Although the phthalocyanine with the longest hydrocarbon chain (C12) has some toxic effect in the absence of light, substantial phototoxic effect was obtained with the optimal combination of drug-irradiation parameters.


Assuntos
Aeromonas hydrophila , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Interações Hidrofóbicas e Hidrofílicas , Indóis/farmacocinética , Fotoquimioterapia , Fármacos Fotossensibilizantes/farmacocinética , Aeromonas hydrophila/efeitos dos fármacos , Aeromonas hydrophila/efeitos da radiação , Relação Dose-Resposta a Droga , Relação Dose-Resposta à Radiação , Farmacorresistência Bacteriana Múltipla , Humanos , Indóis/administração & dosagem , Luz/efeitos adversos , Fármacos Fotossensibilizantes/administração & dosagem
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