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1.
Int J Oncol ; 50(3): 953-963, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28098886

RESUMO

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. ZnPc-induced phototoxicity was studied in two human esophageal cancer cell lines: OE-33 (adenocarcinoma) and Kyse-140 (squamous cell carcinoma). In vitro studies focused on the uptake and intracellular distribution of the novel ZnPc as well as on its growth inhibitory potential, reactive oxygen species (ROS) formation and the induction of apoptosis. The chicken chorioallantoic membrane assay (CAM assay) and studies on native Wistar rats were employed to determine the antineoplastic and antiangiogenic activity of ZnPc-PDT as well as the tolerability and safety of non-photoactivated ZnPc in vivo. ZnPc was taken up by cancer cells in a dose- and time-dependent manner and showed a homogeneous cytoplasmic distribution. Photoactivation of ZnPc-loaded (1-10 µM) cells led to a dose-dependent growth inhibition of esophageal adenocarcinoma and squamous cell carcinoma cells of >90%. The antiproliferative effect was based on ROS-induced cytotoxicity and the induction of mitochondria-driven apoptosis. In vivo studies on esophageal tumor plaques grown on the CAM revealed pronounced antiangiogenic and antineoplastic effects. ZnPc-PDT caused long-lasting changes in the vascular architecture and a marked reduction of tumor feeding blood vessels. Animal studies confirmed the good tolerability and systemic safety of ZnPc, as no changes in immunological, behavioral and organic parameters could be detected upon treatment with the non-photoactivated ZnPc. Our findings show the extraordinary photoactive potential of the novel ZnPc as a photosensitizer for PDT of esophageal cancer.


Assuntos
Inibidores da Angiogênese/farmacologia , Antineoplásicos/farmacologia , Neoplasias Esofágicas/terapia , Indóis/farmacologia , Compostos Organometálicos/farmacologia , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/farmacologia , Inibidores da Angiogênese/efeitos adversos , Inibidores da Angiogênese/farmacocinética , Animais , Antineoplásicos/efeitos adversos , Antineoplásicos/farmacocinética , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Embrião de Galinha , Membrana Corioalantoide/irrigação sanguínea , Membrana Corioalantoide/efeitos dos fármacos , Humanos , Indóis/efeitos adversos , Indóis/farmacocinética , Isoindóis , Compostos Organometálicos/efeitos adversos , Compostos Organometálicos/farmacocinética , Fármacos Fotossensibilizantes/efeitos adversos , Fármacos Fotossensibilizantes/farmacocinética , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo , Compostos de Zinco
2.
Phys Chem Chem Phys ; 18(16): 10964-75, 2016 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-27043894

RESUMO

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. Upon BDP-part excitation, a fast and highly efficient excitation energy transfer (EET) occurred resulting in strong quenching of its fluorescence and the formation of the first excited singlet state of SiPc or MSBDP. It was found that both EET and charge transfer (CT) processes competed with each other in the depopulation of the first excited singlet state of the MSBDP moiety. The former strongly superseded CT in nonpolar toluene, whereas the latter was dominant in a polar environment. Direct or indirect (via EET) excitation of the SiPc-part of the triad was followed by CT yielding the charge-separated (CS) species BDP-SiPc(˙-)-MSBDP(˙+). The energy gap between the CS state and the S1-state of the SiPc moiety was found to be only 0.06 eV in toluene, which facilitated the back CT process and resulted in the appearance of thermally activated delayed fluorescence. With increasing solvent polarity, the energy of the CS state reduced resulting in the disappearance of the delayed fluorescence in CHCl3, tetrahydrofuran or N,N-dimethylformamide. The charge recombination rate, k(CR), was very fast in polar DMF (3.3 × 10(10) s(-1)), whereas this process was two-orders of magnitude slower in nonpolar toluene (k(CR) = 4.0 × 10(8) s(-1)).

3.
Photodiagnosis Photodyn Ther ; 13: 148-157, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26162500

RESUMO

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. Here, we evaluated the suitability of tetra-triethyleneoxysulfonyl substituted zinc phthalocyanine (ZnPc) as novel PS for PDT. ZnPc-induced phototoxicity, induction of apoptosis as well as cell cycle arresting effects was studied in the human gastrointestinal cancer cell lines of different origin. Photoactivation of ZnPc-pretreated (1-10 µM) cancer cells was achieved by illumination with a broad band white light source (400-700 nm) at a power density of 10 J/cm(2). Photoactivation of ZnPc-loaded cells revealed strong phototoxic effects, leading to a dose-dependent decrease of cancer cell proliferation of up to almost 100%, the induction of apoptosis and a G1-phase arrest of the cell cycle, which was associated with decrease in cyclin D1 expression. By contrast, ZnPc-treatment without illumination did not induce any cytotoxicity, apoptosis, cell cycle arrest or decreased cell growth. Antiangiogenic effects of ZnPc-PDT were investigated in vivo by performing CAM assays, which revealed a marked degradation of blood vessels and the capillary plexus of the chorioallantoic membrane of fertilized chicken eggs. Based on our data we think that ZnPc may be a promising novel photosensitizer for innovative PDT.


Assuntos
Indóis/administração & dosagem , Indóis/síntese química , Neoplasias Experimentais/tratamento farmacológico , Compostos Organometálicos/administração & dosagem , Compostos Organometálicos/síntese química , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/administração & dosagem , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Humanos , Isoindóis , Neoplasias Experimentais/patologia , Fármacos Fotossensibilizantes/síntese química , Resultado do Tratamento , Compostos de Zinco
4.
Angew Chem Int Ed Engl ; 53(42): 11370-5, 2014 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-25167966

RESUMO

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). In our design, a single thiazole orange (TO) intercalator dye is linked as a nucleobase surrogate and an adjacent locked nucleic acid (LNA) unit serves to introduce a local constraint. This closes fluorescence decay channels and thereby increases the brightness of the probe-target duplexes. As few as two probes were sufficient to enable the tracking of oskar mRNPs in wild-type living Drosophila melanogaster oocytes.


Assuntos
Benzotiazóis/química , Corantes Fluorescentes/química , Substâncias Intercalantes/química , Oligonucleotídeos/química , Quinolinas/química , Ribonucleotídeos/análise , Animais , Sequência de Bases , Proteínas de Drosophila/genética , Drosophila melanogaster/química , Drosophila melanogaster/genética , Fluorescência , Modelos Moleculares , Hibridização de Ácido Nucleico , RNA Mensageiro/análise
5.
Int J Pharm ; 466(1-2): 382-9, 2014 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-24657286

RESUMO

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. QDs were synthesized by the hydrothermal aqueous route with sizes in the range of 2.0-3.5 nm. Cytotoxic effects of QDs were studied in the human pancreatic carcinoid cell line BON. Cadmium telluride QDs with or without zinc sulfide shell and coated with 3-mercaptopropionic acid (MPA) were highly cytotoxic even at nanomolar concentrations. Capping with l-glutathione (GSH) or thioglycolic acid (TGA) reduced the cytotoxicity of cadmium telluride QDs and cadmium selenide QDs. Determination of the toxicity of QDs revealed IC50 values in the micromolar range. In vivo studies showed good tolerability of CdSe QDs with ZnS shell and GSH capping. We could demonstrate that QDs with ZnS shell and GSH capping exhibit low toxicity and good tolerability in cell models and living organisms. These QDs appear to be promising candidates for biomedical applications such as drug delivery for enhanced chemotherapy or targeted delivery of light sensitive substances for photodynamic therapy.


Assuntos
Compostos de Cádmio/química , Glutationa/química , Pontos Quânticos/química , Pontos Quânticos/toxicidade , Compostos de Selênio/química , Sulfetos/química , Compostos de Zinco/química , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Embrião de Galinha , Membrana Corioalantoide/metabolismo , Sistemas de Liberação de Medicamentos , Humanos
6.
Chem Commun (Camb) ; 49(46): 5277-9, 2013 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-23632437

RESUMO

A bis(permethylated ß-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.


Assuntos
Compostos Aza/química , Compostos de Boro/química , Corantes Fluorescentes/química , Porfirinas/química , beta-Ciclodextrinas/química , Fluorescência , Espectrometria de Fluorescência , Sulfonas/química , Água/química
7.
Phys Chem Chem Phys ; 15(18): 6912-9, 2013 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-23549348

RESUMO

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. The first process delivers the excitation energy to the first excited singlet state of the MSBDP-part upon excitation of the BDP unit. The direct or indirect (via excitation energy transfer) population of the first excited singlet state of the MSBDP moiety is followed by hole transfer to generate the charge-separated state. In non-polar toluene, the probability of charge separation is low, whereas in polar acetonitrile the charge separation quantum yield is close to unity, resulting in strong quenching of the MSBDP fluorescence.


Assuntos
Boro/química , Porfobilinogênio/análogos & derivados , Porfobilinogênio/síntese química , Porfobilinogênio/química , Solventes/química , Espectrofotometria Ultravioleta , Termodinâmica
8.
Chem Commun (Camb) ; 49(29): 2998-3000, 2013 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-23459500

RESUMO

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.


Assuntos
Materiais Biomiméticos/química , Boro/química , Indóis/química , Compostos de Organossilício/química , Complexo de Proteínas do Centro de Reação Fotossintética/química , Porfobilinogênio/análogos & derivados , Materiais Biomiméticos/síntese química , Materiais Biomiméticos/metabolismo , Transferência de Energia , Complexo de Proteínas do Centro de Reação Fotossintética/metabolismo , Porfobilinogênio/química , Espectrofotometria
9.
Phys Chem Chem Phys ; 14(42): 14573-84, 2012 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-23015070

RESUMO

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 ß-cyclodextrin-conjugated subphthalocyanine, a tetrasulfonated porphyrin and a series of silicon(IV) phthalocyanines substituted axially with two ß-cyclodextrins via different spacers. We found that the three components form supramolecular complexes held by host-guest interactions in aqueous solution. Upon excitation of the subphthalocyanine part of the complex, the excitation energy is delivered to the phthalocyanine unit via excitation energy transfer and the porphyrin chromophore acts as an energy transfer bridge enabling this process. It was shown that photo-induced charge transfer also takes place. A sequential electron transfer process from the porphyrin unit to the phthalocyanine moiety and subsequently from the subphthalocyanine moiety to the porphyrin unit takes place, and the probability of this process is controlled by the linker between ß-cyclodextrin and phthalocyanine. The lifetime of the charge-separated state was found to be 1.7 ns by transient absorption spectroscopy.


Assuntos
Indóis/química , Compostos de Organossilício/química , Porfirinas/química , Termodinâmica , beta-Ciclodextrinas/química , Transporte de Elétrons , Isoindóis , Estrutura Molecular , Espectrometria de Fluorescência , Fatores de Tempo
10.
Chem Commun (Camb) ; 48(38): 4597-9, 2012 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-22466224

RESUMO

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


Assuntos
Indóis/química , Porfirinas/química , Ciclodextrinas/química , Transferência de Energia , Isoindóis , Luz
11.
Phys Chem Chem Phys ; 13(39): 17633-41, 2011 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-21887428

RESUMO

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 ß-cyclodextrin units via different spacers. As shown by electronic absorption and fluorescence spectroscopic methods, the two components bind spontaneously in a 1:1 manner in water with large binding constants in the range of 1.1 × 10(7) to 3.5 × 10(8) M(-1). The photophysical properties of the resulting supramolecular complexes have also been studied in detail using steady-state and time-resolved optical spectroscopic methods. It has been found that two major photoinduced processes, namely fluorescence resonance energy transfer and charge transfer are involved which are controlled by the spacer between the ß-cyclodextrin units and the silicon centre of phthalocyanine. Despite the fact that charge transfer is a thermodynamically favourable process for all the complexes, only the ones with a tetraethylene glycol or oxo linker exhibit an efficient charge transfer from the excited phthalocyanine to the porphyrin entity. The lifetimes of the corresponding charge-separated states have been determined to be 200 and 70 ps by picosecond pump-probe experiments.


Assuntos
Indóis/química , Compostos de Organossilício/química , Porfirinas/química , beta-Ciclodextrinas/química , Eletroquímica , Estrutura Molecular , Processos Fotoquímicos , Espectrometria de Fluorescência , Termodinâmica
12.
Phys Chem Chem Phys ; 12(27): 7366-70, 2010 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-20520887

RESUMO

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.


Assuntos
Transferência de Energia/efeitos da radiação , Indóis/efeitos da radiação , Luz , Fotossíntese , Porfirinas/efeitos da radiação , beta-Ciclodextrinas/efeitos da radiação , Transferência de Energia/fisiologia , Indóis/química , Isoindóis , Porfirinas/química , Análise Espectral , Água/química , beta-Ciclodextrinas/química
13.
Phys Chem Chem Phys ; 11(30): 6430-40, 2009 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-19809675

RESUMO

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). The first process delivers the excitation to the first excited singlet state of the Pc-part upon initial BDP-part excitation. The probability of EET supersedes that of CT in toluene, whereas the latter transfer process dominates in BDP-part depopulation when triads are dissolved in polar DMF. The direct or indirect (via EET) population of Pc moiety is followed by the hole transfer to the charge-separated state in 4 (in DMF) and in 5 (in DMF and toluene). At the same time, it was found that CT is energetically unfavorable for the triad 4 in toluene upon excitation of the Pc-part. The charge-recombination in DMF occurs very fast with a decay time of 40 and 30 ps for 4 and 5, respectively, whereas toluene stabilizes the charge-separated state, prolonging the lifetime to 4.5 and 1.7 ns, respectively.


Assuntos
Corantes/química , Indóis/química , Compostos de Organossilício/química , Fotoquímica/métodos , Espectrofotometria/métodos , Boro/química , Físico-Química/métodos , Eletroquímica/métodos , Elétrons , Luz , Modelos Químicos , Modelos Estatísticos , Estrutura Molecular , Espectrometria de Fluorescência/métodos , Fatores de Tempo , Tolueno/química
14.
J Chem Phys ; 130(13): 134509, 2009 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-19355753

RESUMO

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. For all investigated free-base porphyrins, the equilibrium concentration of one tautomer, named T1, which has a lower frequency of the S(0,0)-->S(1,0) transition, was found to be higher than the concentration of the other tautomer, named T2, even at room temperature. Lowering the temperature enriches the population of tautomer T1 and it becomes dominant in absorption and fluorescence. The fluorescence decay time of tautomer T1 was found to be approximately three times shorter compared to that of tautomer T2, whereas both tautomers have similar fluorescence quantum yields. In contrast only one conformation exists for zinc cycloketo-porphyrin, which was used as reference compound.


Assuntos
Porfirinas/química , Análise Espectral , Isomerismo , Modelos Químicos , Modelos Teóricos , Estereoisomerismo
15.
Chem Commun (Camb) ; (12): 1517-9, 2009 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-19277375

RESUMO

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.


Assuntos
Compostos de Boro/química , Elétrons , Indóis/química , Silício/química , Corantes Fluorescentes/química , Isoindóis , Estrutura Molecular , Fotoquímica , Radiossensibilizantes/química , Tolueno/química
16.
J Phys Chem B ; 112(29): 8466-76, 2008 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-18582011

RESUMO

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 photophysical properties of all possible NH tautomers of metal-free dinuclear Pc have been fully characterized. In the first tautomer, Pc(parallel), both pairs of hydrogen atoms are parallel to the connection line of two Pc units. The maximum of the lowest-energy Q absorption band, lambda abs, in Pc(parallel) is located at 832 nm, whereas the spectral position of the fluorescence maximum lies at lambdafl=837 nm. The second NH tautomer, Pc(perpendicular) (lambdaabs=853 nm, lambdafl=860 nm), presents the two pairs of hydrogen atoms perpendicularly orientated to the covalent axis, and the third one, Pc(mix) (lambdaabs=864 nm, lambdafl=872 nm), contributing in a minor extend to the absorption and fluorescence spectra of the metal-free dinuclear phthalocyanine, has one perpendicular and one parallel pair of hydrogen atoms. Obviously, only one configuration exists in the case of the Zn(II)-containing dinuclear phthalocyanine (lambdaabs=845 nm, lambdafl=852 nm).

17.
J Phys Chem B ; 111(28): 8053-62, 2007 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-17583942

RESUMO

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. The first process results in appearance of the Pc fluorescence when the P-part is initially excited, and plays a dominant role in fast depopulation of the first excited singlet state of the P moiety. If the first excited singlet state of the Pc-part is populated (either directly or via EET), it undergoes fast depopulation by hole transfer (HT) to the charge-separated (CS) state. In polar DMF, the CS state is the lowest excited state, and the charge recombination occurs directly to the ground state. Using transient absorption spectroscopy, the lifetime of the CS state was estimated to be 30 and 20 ps for H2Tr and ZnTr, respectively. In nonpolar toluene, the energy gap between the first excited singlet state of the Pc-part and the CS state is very small, and back HT occurs in both triads, resulting in appearance of "delayed fluorescence" of the Pc-part with a decay time similar to the lifetime of the CS state (190 and 280 ps for H2Tr and ZnTr, respectively). Since the energy of the CS state of ZnTr in toluene is lower than that of H2Tr, the probability of back HT for ZnTr is lower. This was clearly proved by decay-associated fluorescence spectral measurements.


Assuntos
Compostos Heterocíclicos/química , Indóis/química , Porfirinas/química , Solventes/química , Zinco/química , Eletroquímica , Transporte de Elétrons , Transferência de Energia , Isoindóis , Estrutura Molecular , Silício/química , Espectrofotometria Atômica , Espectrofotometria Ultravioleta
18.
Bioconjug Chem ; 18(4): 1078-86, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17550226

RESUMO

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.g., an antibody) serves to direct the drug to its target, and a multiplying unit has the role of increasing the number of biological active moieties the system can carry. In this paper, we report on the synthesis of a modular carrier system in which the role of multiplying unit is given to a [5:1]fullerene hexakis adduct. This fullerene hexaadduct has five malonate spacers which can bind two therapeutic units (the photosensitizer pyropheophorbide-a) each, for a total of ten, and a longer malonate spacer which serves for the conjugation to the addressing unit, the monoclonal antibody rituximab. Confocal microscopy studies using Epstein-Barr virus-transformed B-lymphocytes and Jurkat cells showed that the antibody conjugate conserves the affinity for its receptor (CD20) and its selectivity toward CD20 positive B-lymphocytes. On the contrary, the antibody-free complex did not show any bounding or intracellular uptake.


Assuntos
Anticorpos Monoclonais/química , Antineoplásicos/química , Clorofila/análogos & derivados , Fulerenos/química , Imunoconjugados/química , Fotoquimioterapia , Fármacos Fotossensibilizantes/química , Anticorpos Monoclonais/farmacologia , Anticorpos Monoclonais Murinos , Antígenos CD20/imunologia , Antineoplásicos/farmacologia , Linfócitos B/efeitos dos fármacos , Linfócitos B/imunologia , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Clorofila/química , Clorofila/farmacologia , Portadores de Fármacos , Fulerenos/farmacologia , Humanos , Imunoconjugados/farmacologia , Linfoma de Células B/tratamento farmacológico , Linfoma de Células B/imunologia , Fármacos Fotossensibilizantes/farmacologia , Rituximab , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia
19.
J Phys Chem B ; 111(5): 998-1006, 2007 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-17266254

RESUMO

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. For P6, due to shorter distances between neighboring dye molecules, stronger interactions between pyropheophorbide a units than for FHP6 were observed. As a consequence, the excitation energy is delivered rapidly to traps formed by stacked pyropheophorbide a molecules resulting in the reduction of fluorescence, intersystem crossing, and singlet oxygen quantum yields compared to the values of FHP6. For FP6 the reduction of these values is much stronger due to an additional fast and efficient deactivation process, namely photoinduced electron transfer from pyropheophorbide a to the fullerene moiety. Consequently, FP6 can be considered as a combination of a light-harvesting system consisting of several separate pyropheophorbide a molecules and a charge-separating center.


Assuntos
Clorofila/análogos & derivados , Elétrons , Fulerenos/química , Clorofila/síntese química , Clorofila/química , Transferência de Energia , Modelos Moleculares , Estrutura Molecular , Fotoquímica , Sensibilidade e Especificidade , Espectrofotometria Ultravioleta/métodos
20.
Chemistry ; 12(5): 1468-74, 2006 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-16308880

RESUMO

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. Fluorescence quantum yields, fluorescence lifetimes and singlet-oxygen quantum yields of the compounds were determined.


Assuntos
Indóis/química , Radiossensibilizantes/química , Fluorescência , Indóis/síntese química , Isoindóis , Estrutura Molecular , Fotoquímica , Radiossensibilizantes/síntese química
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