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1.
J Photochem Photobiol B ; 194: 21-31, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30897400

RESUMO

Aedes aegypti mosquitos are widespread vectors of several diseases and their control is of primary importance for biological and environmental reasons, and novel safe insecticides are highly desirable. An eco-friendly photosensitizing magnetic nanocarrier with larvicidal effects on Aedes aegypti was proposed. The innovative core-shell hybrid nanomaterial was synthesized by combining peculiar magnetic nanoparticles (called Surface Active Maghemite Nanoparticles - SAMNs, the core) and chlorin-e6 as photosensitizer (constituting the shell) via self-assembly in water. The hybrid nanomaterial (SAMN@chlorin) was extensively characterized and tested for the photocidal activity on larvae of Aedes aegypti. The SAMN@chlorin core-shell nanohybrid did not present any toxic effect in the dark, but, upon light exposure, showed a higher photocidal activity than free chlorin-e6. Moreover, the eco-toxicity of SAMN@chlorin was determined in adults and neonates of Daphnia magna, where delayed toxicity was observed only after prolonged (≥4 h) exposure to intense light, on the green alga Pseudokirchneriella subcapitata and on the duckweed Lemna minor on which no adverse effects were observed. The high colloidal stability, the physico-chemical robustness and the magnetic drivability of the core-shell SAMN@chlorin nanohybrid, accompanied by the high photocidal activity on Aedes aegypti larvae and reduced environmental concerns, can be proposed as a safe alternative to conventional insecticides.


Assuntos
Aedes , Compostos Férricos/química , Inseticidas/química , Larva , Nanopartículas/química , Porfirinas/química , Animais , Clorofíceas/efeitos dos fármacos , Clorofíceas/efeitos da radiação , Daphnia/efeitos dos fármacos , Daphnia/efeitos da radiação , Inseticidas/toxicidade , Luz , Porfirinas/toxicidade , Propriedades de Superfície , Água/química
2.
Photochem Photobiol Sci ; 15(5): 618-25, 2016 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-27064601

RESUMO

Photodynamic therapy (PDT) is a treatment of cancer whereby tumours are destroyed by reactive oxygen species generated upon photoactivation of a photosensitizer drug. Hydrophobic photosensitizers are known to be ideal for PDT; however, their hydrophobicity necessitates that they are typically administered using emulsions. Here, a delivery vehicle for photodynamic therapy based on the co-self-assembly of both a Zn(ii)-phthalocyanine derivative photosensitizer and a polyethylene glycol (PEG) derivative onto gold nanoparticles is reported. The PEG on the particle surface ensured that the conjugates were water soluble and enhanced their retention in the serum, improving the efficiency of PDT in vivo. The pharmacokinetic behaviour of the nanoparticle conjugates following intravenous injection into C57/BL6 mice bearing a subcutaneous transplanted B78H1 amelanotic melanoma showed a significant increase of retention of the nanoparticles in the tumour. PDT tumour destruction was achieved 3 h following injection of the nanoparticle conjugates leading to a remarkable 40% of the treated mice showing no tumour regrowth and complete survival. These results highlight that dual functionalised nanoparticles exhibit significant potential in PDT of cancer especially for difficult to treat cancers such as amelanotic melanoma.


Assuntos
Portadores de Fármacos/química , Indóis/administração & dosagem , Melanoma Amelanótico/tratamento farmacológico , Compostos Organometálicos/administração & dosagem , Fármacos Fotossensibilizantes/administração & dosagem , Neoplasias Cutâneas/tratamento farmacológico , Pele/efeitos dos fármacos , Animais , Feminino , Ouro/química , Interações Hidrofóbicas e Hidrofílicas , Indóis/química , Indóis/farmacocinética , Indóis/uso terapêutico , Isoindóis , Melanoma Amelanótico/metabolismo , Melanoma Amelanótico/patologia , Nanopartículas Metálicas/química , Camundongos Endogâmicos C57BL , Compostos Organometálicos/química , Compostos Organometálicos/farmacocinética , Compostos Organometálicos/uso terapêutico , Fotoquimioterapia , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacocinética , Fármacos Fotossensibilizantes/uso terapêutico , Polietilenoglicóis/química , Pele/metabolismo , Pele/patologia , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Compostos de Zinco
3.
J Mater Chem B ; 3(15): 3001-3010, 2015 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-32262500

RESUMO

We have developed a multifunctional polymer-based nanoplatform for bimodal cancer phototherapy. It was achieved by electrostatic entangling of two anionic photoactivable components, a commercial porphyrin and a tailored nitro-aniline derivative, within the cationic shell of polymeric nanoparticles (NPs) based on polymethyl methacrylate. The combination of steady-state and time-resolved spectroscopic and photochemical techniques shows that the two photoresponsive agents do not interfere with each other while being in close proximity in the same polymeric scaffold and can thus operate in parallel under the exclusive control of light stimuli. Specifically, visible light triggers satisfactory red fluorescence emission and generation of singlet oxygen (1O2) from one component and release of nitric oxide (NO) from the other. Fluorescence microscopy analysis provides unambiguous evidence for the internalization of the NPs within B78H1 melanoma cells, where they induce amplified mortality due to a combinatory effect of the two photogenerated cytotoxic species.

4.
Acta Trop ; 123(3): 239-43, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22668835

RESUMO

Biolarvicides, such as microbial formulations based on Bacillus thuringiensis and B. sphaericus, have been found to be highly effective against mosquito larvae and are currently employed as eco-friendly alternatives to synthetic chemical insecticides for vector control. Recently, a porphyrin of natural origin has been suggested as a sunlight-activatable larvicide against the dengue vector Aedes aegypti. In order to validate the approach for the control of the malaria vector, we tested the photo-larvicidal activity of a novel porphyrin, namely meso-tri(N-methyl-pyridyl), mono(N-dodecyl-pyridyl)porphine, C12, associated with two specifically selected carriers, against Anopheles gambiae s.s. and An. arabiensis larvae, both laboratory reared and collected from malaria endemic sites in Burkina Faso. Both C12-porphyrin formulates, when administered to larvae at a 50µM porphyrin dose, were accumulated in the alimentary canal. Subsequent exposure of the porphyrin-loaded larvae to sunlight for short times (0.5-3h) led to a complete mortality. The high efficacy exhibited by a "foodstuff" porphyrin formulate also in the presence of typical larval food particles opens promising perspectives for the development of an effective photocidal larvicide.


Assuntos
Anopheles/efeitos dos fármacos , Inseticidas/farmacologia , Controle de Mosquitos/métodos , Porfirinas/farmacologia , Luz Solar , Animais , Bacillus thuringiensis/patogenicidade , Burkina Faso , Feminino , Inseticidas/química , Larva/efeitos dos fármacos , Controle Biológico de Vetores/métodos , Porfirinas/química , Análise de Sobrevida
5.
Photochem Photobiol Sci ; 11(2): 294-301, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22011789

RESUMO

The increasing use of photosensitized processes for disinfection of microbiologically polluted waters requires a precise definition of the factors controlling the degree of photosensitivity in target and non-target organisms. In this regard, tests with protozoa and invertebrates which have a natural habitat in such waters may be used as first screening methods for the assessment of possible hazards for the ecosystem. A new cationic porphyrin, namely meso-tri(N-methyl-pyridyl)mono(N-dodecyl-pyridyl)porphine (C12), is tested in this work on the protozoan Ciliophora Colpoda inflata and Tetrahymena thermophila and the Crustacea Branchiopoda Artemia franciscana and Daphnia magna. The protocol involved 1 h incubation with porphyrin doses in the 0.1-10.0 µM range and subsequent irradiation with visible light at a fluence rate of 10 mW cm(-2). The results indicate that C12 porphyrin has a significant affinity for C. inflata and T. thermophila; this is also shown by fluorescence microscopic analyses. C. inflata cysts were resistant to the phototreatment up to a porphyrin dose of 0.6 µM. The effects of C12 on cysts have been evaluated at 3 and 24 h after the end of the phototreatment; a delay in the excystment process was observed. T. thermophila was fairly resistant to the phototreatment with C12 porphyrin. The data obtained with the two crustaceans indicated that the effects of dark- and photo-treatment with C12 need to be closely examined for every organism. A. franciscana is more resistant, probably owing to its ability to adapt to extreme conditions, while the high level of photosensitivity displayed by Daphnia magna represents a potential drawback, as this organism is often selected as a reference standard for assessing the environmental safety. Thus, while C12 photosensitisation can represent a useful tool for inducing a microbicidal or larvicidal action on polluted waters, the irradiation protocols must be carefully tailored to the nature of the specific water basin, and in particular to its biotic characteristics.


Assuntos
Artemia/efeitos dos fármacos , Daphnia/efeitos dos fármacos , Água Doce/microbiologia , Insetos Vetores/efeitos dos fármacos , Porfirinas/farmacologia , Tetrahymena thermophila/efeitos dos fármacos , Poluição Química da Água/prevenção & controle , Animais , Anti-Infecciosos/farmacologia , Artemia/efeitos da radiação , Cílios/efeitos dos fármacos , Cílios/efeitos da radiação , Daphnia/efeitos da radiação , Escuridão , Ecossistema , Controle de Insetos , Insetos Vetores/efeitos da radiação , Fármacos Fotossensibilizantes/farmacologia , Compostos de Piridínio , Tetrahymena thermophila/citologia , Tetrahymena thermophila/efeitos da radiação , Trofozoítos/efeitos dos fármacos , Trofozoítos/efeitos da radiação
6.
J Environ Pathol Toxicol Oncol ; 30(3): 261-71, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22126619

RESUMO

Porphyrins have been shown to act as very efficient photosensitizing agents against a broad number of microbial pathogens, including bacteria, fungi, and protozoa. This property has promising applications at a clinical level for the treatment of infectious diseases by photodynamic therapy. Moreover, this technique is also being used to address environmental problems of high significance, such as the decontamination of wastewaters, the disinfection of fish-farming tanks, the protection of animal species (e.g., amphibians and reptiles) that are endangered by pathogens whose life cycle takes place largely in aqueous media, and the control of populations of noxious insects. Such diversified applications take advantage of the availability of a truly large number of porphyrin derivatives with chemical structures that can be tailored to comply with the physical and chemical properties as well as the biological features of several milieus. In addition, the property typical of porphyrins to absorb essentially all of the wavelengths in the sun emission spectrum allows the promotion of processes largely based on natural resources with significant energy savings and low impact on ecosystems.


Assuntos
Infecções Bacterianas/prevenção & controle , Micoses/prevenção & controle , Fotoquimioterapia , Fármacos Fotossensibilizantes/uso terapêutico , Infecções por Protozoários/prevenção & controle , Poluentes da Água/efeitos adversos , Animais , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/etiologia , Biodiversidade , Desinfecção , Ecossistema , Humanos , Insetos , Micoses/tratamento farmacológico , Micoses/etiologia , Porfirinas/uso terapêutico , Infecções por Protozoários/tratamento farmacológico , Infecções por Protozoários/etiologia
7.
PLoS Negl Trop Dis ; 5(12): e1434, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22206031

RESUMO

BACKGROUND: Control of the mosquito vector population is the most effective strategy currently available for the prevention of dengue fever and the containment of outbreaks. Photo-activated oxidants may represent promising tools for developing effective, safe and ecofriendly novel larvicides. The purpose of this study was to evaluate the potential of the synthetic meso-substituted porphyrin meso-tri(N-methylpyridyl), meso-mono(N-tetradecylpyridyl)porphine (C14) as a photoactivatable larvicide against the dengue vector Aedes (Stegomyia) aegypti. METHODOLOGY: The photophysical and photochemical properties of the C14 molecule were assessed spectrophotometrically. Photomediated larvicidal efficacy, route of intake and site of action were determined on Ae. aegypti larvae by laboratory bioassays and fluorescence microscopy. Using powdered food pellet for laboratory rodents (a common larval food used in the laboratory) as a carrier for C14, loading-release dynamics, larvicidal efficacy and residual activity of the C14-carrier complex were investigated. MAIN FINDINGS: The C14 molecule was found to exert a potent photosensitizing activity on Ae. aegypti larvae. At irradiation intervals of 12 h and 1 h, at a light intensity of 4.0 mW/cm(2), which is 50-100 times lower than that of natural sunlight, LC(50) values of 0.1 µM (0.15 mg/l) and 0.5 µM (0.77 mg/l) were obtained, respectively. The molecule was active after ingestion by the larvae and caused irreversible, lethal damage to the midgut and caecal epithelia. The amphiphilic nature of C14 allowed a formulate to be produced that not only was as active against the larvae as C14 in solution, but also possessed a residual activity of at least two weeks, in laboratory conditions. CONCLUSIONS: The meso-substituted synthetic porphyrin C14, thanks to its photo-sensitizing properties represents an attractive candidate for the development of novel photolarvicides for dengue vector control.


Assuntos
Aedes/efeitos dos fármacos , Inseticidas/administração & dosagem , Inseticidas/química , Fármacos Fotossensibilizantes/administração & dosagem , Fármacos Fotossensibilizantes/química , Porfirinas/administração & dosagem , Porfirinas/química , Animais , Bioensaio , Dengue/prevenção & controle , Vetores de Doenças , Inseticidas/isolamento & purificação , Inseticidas/farmacocinética , Mucosa Intestinal/efeitos dos fármacos , Larva/efeitos dos fármacos , Luz , Microscopia de Fluorescência , Fármacos Fotossensibilizantes/isolamento & purificação , Fármacos Fotossensibilizantes/farmacocinética , Porfirinas/isolamento & purificação , Porfirinas/farmacocinética , Espectrofotometria , Análise de Sobrevida
8.
Nature ; 444(7121): 835, 2006 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-17167469

RESUMO

Amber provides an effective medium for conservation of soft-bodied microorganisms, but finds older than 135 million years are very rare and have not so far contained any microbial inclusions. Here we describe 220-million-year-old droplets of amber containing bacteria, fungi, algae and protozoans that are assignable to extant genera. These inclusions provide insight into the evolution and palaeoecology of Lower Mesozoic microorganisms: it seems that the basal levels of food webs of terrestrial communities (biocoenoses) have undergone little or no morphological change from the Triassic to the Recent.


Assuntos
Âmbar , Biodiversidade , Fósseis , Microbiologia , Animais , Bactérias/isolamento & purificação , Eucariotos/isolamento & purificação , Fungos/isolamento & purificação , Fatores de Tempo
9.
Lasers Surg Med ; 38(5): 468-81, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16788934

RESUMO

BACKGROUND AND OBJECTIVES: Photodynamic therapy (PDT) appears to be endowed with several favorable features for the treatment of infections originated by microbial pathogens, including a broad spectrum of action, the efficient inactivation of antibiotic-resistant strains, the low mutagenic potential, and the lack of selection of photoresistant microbial cells. Therefore, intensive studies are being pursued in order to define the scope and field of application of this approach. RESULTS: Optimal cytocidal activity against a large variety of bacterial, fungal, and protozoan pathogens has been found to be typical of photosensitizers that are positively charged at physiological pH values (e.g., for the presence of quaternarized amino groups or the association with polylysine moieties) and are characterized by a moderate hydrophobicity (n-octanol/water partition coefficient around 10). These photosensitizers in a micromolar concentration can induce a >4-5 log decrease in the microbial population after incubation times as short as 5-10 minutes and irradiation under mild experimental conditions, such as fluence-rates around 50 mW/cm2 and irradiation times shorter than 15 minutes. CONCLUSIONS: PDT appears to represent an efficacious alternative modality for the treatment of localized microbial infections through the in situ application of the photosensitizer followed by irradiation of the photosensitizer-loaded infected area. Proposed clinical fields of interest of antimicrobial PDT include the treatment of chronic ulcers, infected burns, acne vulgaris, and a variety of oral infections.


Assuntos
Infecções Bacterianas/tratamento farmacológico , Micoses/tratamento farmacológico , Doenças Parasitárias/tratamento farmacológico , Fotoquimioterapia , Acne Vulgar/tratamento farmacológico , Bactérias/ultraestrutura , Humanos , Técnicas In Vitro , Doenças Periodontais/tratamento farmacológico , Doenças Periodontais/microbiologia , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacologia , Cicatrização/efeitos dos fármacos , Ferimentos e Lesões/tratamento farmacológico , Ferimentos e Lesões/microbiologia
10.
Photochem Photobiol Sci ; 2(6): 668-72, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12859151

RESUMO

Incubation of Acanthamoeba palestinensis cells with a tetracationic phthalocyanine (RLP068) at concentrations ranging between 0.2 and 1.0 microM, caused a ready uptake of the photosensitizer with recoveries of the order of 0.5-2.5 nmol per mg of cell protein. The amount of cell-bound phthalocyanine did not appreciably change with incubation times ranging between 0.5 and 3 h. Fluorescence microscopic investigations showed an obvious accumulation of the phthalocyanine at the level of the vacuolar membranes. A nearly complete photoinduced cell death occurred upon irradiating A. palestinensis cells with 600-700 nm light with a total energy of 15-30 J cm(-2) using 1.0 microM RLP068 in the incubation medium. DAPI staining of the photosensitized cells indicates significant damage of the nucleus. On the other hand, photosensitization of the protozoan cells does not directly involve the mitochondria as shown by the lack of photoinduced decrease in the activity of typical mitochondrial enzymes, such as NADH dehydrogenase and citrate synthase.


Assuntos
Acanthamoeba/efeitos dos fármacos , Acanthamoeba/efeitos da radiação , Indóis/farmacologia , Compostos Organometálicos/farmacologia , Fármacos Fotossensibilizantes/farmacologia , Acanthamoeba/citologia , Animais , Morte Celular/efeitos dos fármacos , Morte Celular/efeitos da radiação , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/efeitos da radiação , Citrato (si)-Sintase/metabolismo , Relação Dose-Resposta a Droga , Indóis/química , Indóis/farmacocinética , Isoindóis , Microscopia de Fluorescência , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/efeitos da radiação , NADH Desidrogenase/metabolismo , Compostos Organometálicos/química , Compostos Organometálicos/farmacocinética , Fotoquimioterapia/métodos , Transtornos de Fotossensibilidade , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacocinética
11.
Photochem Photobiol Sci ; 1(8): 560-4, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12659497

RESUMO

Colpoda inflata cysts accumulate significantly large amounts of meso-substituted cationic porphyrins, including meso-tetrakis(N-methyl-4-pyridyl)porphine (TMP-C1) and its mono-N-methyldecyl (TMP-C10) and -tetradecyl (TMP-C14) analogues upon incubation for 1 h with 1-48 microM porphyrin concentrations. All three porphyrins at concentrations greater than 10 microM exhibited a significant toxicity toward the cysts, in particular lowering the degree of excystment. Upon visible light irradiation of the porphyrin-loaded cysts, extensive photodamage was observed even in the presence of 1 microM porphyrin, as shown by light microscopy observations and counting of vegetative emerging cells The presence of one decyl or tetradecyl hydrocarbon chain caused about 10-fold enhancement of the phototoxic effects.


Assuntos
Eucariotos/efeitos dos fármacos , Fármacos Fotossensibilizantes/farmacologia , Porfirinas/farmacologia , Animais , Cátions , Eucariotos/efeitos da radiação , Microscopia
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