Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Environ Technol ; : 1-12, 2021 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-33390095

RESUMO

This work proposes a novel technology for environmental remediation based on mesoporous silica spheres, which were successfully synthesized by the solvothermal method using the cetyltrimethylammonium bromide as a structuring agent. The adsorbent was designed to remove cationic dyes at strong acidic conditions. The surface was modified by a careful thermal treatment aiming at the condensation of silanol to siloxane groups. The adsorbent was characterized by XRD, SEM, FTIR, N2 adsorption/desorption and the equilibrium technique to determine the pHpzc. The kinetic of the adsorption followed a pseudo-second-order model and the process was ruled by physical forces. The isotherms were fitted to Freundlich and Temkin models, indicating that the physisorption occurred with multilayer formation, with the interaction adsorbate-adsorbate being relevant to the whole process. The adsorption capacity was approximately 60 mg g-1 and the adsorbents performance in the fast-contact system showed removal of 65%wt. of a 93 mg L-1 methylene blue (MB) solution in a single application.

2.
J Photochem Photobiol B ; 212: 112039, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33002779

RESUMO

In this study we report a novel theranostic lipid-polymer liposome, obtained from DPPC and the triblock copolymer F127 covalently modified with 5(6)-carboxyfluorescein (CF) for photodynamic applications. Due to the presence of F127, small unilamellar vesicle (SUV) liposomes were synthesized by a simple and fast thin-film hydration method without the need for an extrusion process. The vesicles have around 100 nm, low polydispersity and superb solution stability. The clinically used photosensitizer verteporfin (VP) was entrapped into the vesicles, mostly in monomeric form, with 90% loading efficiency. Stern-Volmer and fluorescence lifetime assays showed heterogeneous distribution of the VP and CF into the vesicles, ensuring the integrity of their individual photophysical properties. The theranostic properties were entirely photoactivatable and can be trigged by a unique wavelength (470 nm). The feasibility of the system was tested against the Glioblastoma multiforme cell line T98G. Cellular uptake by time-resolved fluorescence microscopy showed monomerized VP (monoexponential decay, 6.0 ns) at nucleus level, while CF was detected at the membrane by fluorescence microscopy. The strategy's success was supported by the reduction of 98% in the viability of T98G cells by the photoactivated lipid-polymer liposome with [VP] = 1.0 µmol L-1. Therefore, the novel theranostic liposome is a potential system for use in cancer and ocular disease therapies.

3.
J Mater Chem B ; 2020 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-32936201

RESUMO

We report herein the design, preparation, characterization and biological evaluation of a thermoresponsive gel based on binary mixtures of Pluronic® co-polymers F127 and P123, the latter being covalently functionalized with a nitric oxide (NO) photodonor (NOPD). The weight ratio between the two polymeric components is optimized in order to observe gelation of their saline water solution in the range of 32-35 °C, in order to exploit the therapeutic properties of NO for potential ocular applications. Rheological measurements were performed to evaluate the gelation temperature and, hence, to select a co-polymer mixture specifically appropriate for the reference application. Integration of the NOPD into the polymeric scaffold does not affect its rheological and spectroscopic properties, making it a good absorber of visible light both in solution and in the gel phase. Irradiation of the saline solution of the polymeric components with visible light triggers NO release, which occurs with an efficiency of more than one order of magnitude faster than that observed for the isolated NOPD. The polymeric system fully preserves such photobehavior after gelation as demonstrated by the effective NO photorelease from the gel matrix and its diffusion in the supernatant upon illumination. The gel is well-tolerated in both dark and light conditions by corneal cells, while being able to induce growth inhibition towards Staphylococcus aureus under visible light irradiation and has high moduli which can contribute to an adequate retention time within the eyes.

4.
Molecules ; 25(16)2020 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-32784931

RESUMO

ß-Cyclodextrin (ß-CD) is an oligosaccharide composed of seven units of D-(+)-glucopyranose joined by α-1,4 bonds, which is obtained from starch. Its singular trunk conical shape organization, with a well-defined cavity, provides an adequate environment for several types of molecules to be included. Complexation changes the properties of the guest molecules and can increase their stability and bioavailability, protecting against degradation, and reducing their volatility. Thanks to its versatility, biocompatibility, and biodegradability, ß-CD is widespread in many research and industrial applications. In this review, we summarize the role of ß-CD and its derivatives in the textile industry. First, we present some general physicochemical characteristics, followed by its application in the areas of dyeing, finishing, and wastewater treatment. The review covers the role of ß-CD as an auxiliary agent in dyeing, and as a matrix for dye adsorption until chemical modifications are applied as a finishing agent. Finally, new perspectives about its use in textiles, such as in smart materials for microbial control, are presented.

5.
Colloids Surf B Biointerfaces ; 181: 837-844, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31252220

RESUMO

Liposomes are membrane models and excellent Drug Delivery Systems. However, their preparation is expensive, labor intensive, time consuming, and sometimes toxic. Recently, we published an innovative methodology for the production of homogeneous Small Unilamellar Vesicles (SUV) through a simple, fast, relatively low cost, and reproducible process that resulted in very stable vesicles. The methodology involves a small amount of F127 triblock Pluronic® copolymer (0.02% m/V) to a phospholipid (DPPC, DOPC, and DSPC), followed by the solid dispersion methodology. After that, during the thin-film hydration process (of lipids and F127), SUVs are quickly formed after 30 s of sonication using bath equipment at a low frequency of 42 kHz. The resultant colloidal solution was homogeneous with liposomes lower than ˜100 nm of hydrodynamic diameter. The SUV formation is highly temperature dependent. However, it functions independently from the lipid´s phase (gel or liquid-crystal phases). A preparation with Pluronic P123 did not lead to homogeneous SUV. We found that the conditions for SUV formation feature a mixture of F127 and lipids at above a critical temperature. This temperature is not the copolymer´s CMT (micelle is not required). Interestingly, the long PEO groups of F127 play an essential role in this SUV formation, which is proposed to be governed by the "Budding Off" model. The findings show a complex combination of factors: a sum of the sonoporation, the oscillation effects of the compressed/dilated regions, the frequency of oscillation, and the temperature-dependence on long PEO groups. Also, the outer lipid monolayer interaction might by responsible for generating "daughter" vesicles from "mother" vesicles in the mechanism.


Assuntos
Sonicação , Tamanho da Partícula , Poloxaleno/química , Poloxâmero/química , Propriedades de Superfície , Temperatura , Lipossomas Unilamelares/síntese química , Lipossomas Unilamelares/química
6.
Nanomaterials (Basel) ; 9(6)2019 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-31159241

RESUMO

This contribution reports the design, preparation, photophysical and photochemical characterization, as well as a preliminary biological evaluation of mesoporous silica nanoparticles (MSNs) covalently integrating a nitric oxide (NO) photodonor (NOPD) and a singlet oxygen (1O2) photosensitizer (PS) and encapsulating the anticancer doxorubicin (DOX) in a noncovalent fashion. These MSNs bind the NOPD mainly in their inner part and the PS in their outer part in order to judiciously exploit the different diffusion radius of the cytotoxic NO and 1O2. Furthermore this silica nanoconstruct has been devised in such a way to permit the selective excitation of the NOPD and the PS with light sources of different energy in the visible window. We demonstrate that the individual photochemical performances of the photoactive components of the MSNs are not mutually affected, and remain unaltered even in the presence of DOX. As a result, the complete nanoconstruct is able to deliver NO and 1O2 under blue and green light, respectively, and to release DOX under physiological conditions. Preliminary biological results performed using A375 cancer cells show a good tolerability of the functionalized MSNs in the dark and a potentiated activity of DOX upon irradiation, due to the effect of the NO photoreleased.

7.
Colloids Surf B Biointerfaces ; 175: 530-544, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30579054

RESUMO

Liposomes are very attractive membrane models and excellent drug delivery systems. Concerning their drug delivery aspects, the mixing liposomes with biocompatible copolymers allows for stability and the incorporation of several drugs. We developed PEG coated vesicles from the mixture of DPPC and F127 Pluronic copolymer to obtain long-circulating nanoparticles (mixed vesicles). We employed an innovative process previously developed by us: a small amount of F127 mixed in DPPC, thin film preparation, followed by hydration (lipids plus F127) using a bath sonicator cleaner type, forming unilamellar spherical vesicles with diameter ∼100 nm. The formed PEG coated vesicles were incorporated with the xanthene dye Erythrosine B (ERY), and its ester derivatives as photosensitizers (PS) for photodynamic proposes. The F127/DPPC mixed vesicles promoted a higher PS incorporation, and with better thermal and kinetic stability, at least 60 days, when compared to conventional DPPC liposome. The binding constant and quenching analysis revealed that with a higher PS hydrophobicity, PS affinity increases toward the nanoparticle and results in a deeper PS location inside the lipid bilayer. An increment in the fluorescence quantum yield was observed, while the PS singlet oxygen generations remained high. Dialysis studies demonstrated that PS were released based on their hydrophobicity. Permeation analysis showed that all PS can reach the deeper regions of the skin. The Decyl Ester derivative/nanoparticle exhibited high photoactivity against Caco-2 cancer cells (in vitro studies). The PEG coated from F127/DPPC mixed vesicles are very promising nanocarriers for erythrosine and its derivatives.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Eritrosina/farmacologia , Lipossomos/química , Fármacos Fotossensibilizantes/farmacologia , Pele/efeitos dos fármacos , 1,2-Dipalmitoilfosfatidilcolina/química , Animais , Células CACO-2 , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Composição de Medicamentos/métodos , Orelha , Eritrosina/análogos & derivados , Eritrosina/química , Ésteres , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Humanos , Interações Hidrofóbicas e Hidrofílicas , Luz , Lipossomos/metabolismo , Lipossomos/farmacocinética , Lipossomos/efeitos da radiação , Permeabilidade , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/química , Poloxâmero/química , Polietilenoglicóis/química , Oxigênio Singlete/química , Oxigênio Singlete/metabolismo , Pele/metabolismo , Sonicação , Suínos
8.
Chemistry ; 24(30): 7664-7670, 2018 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-29603456

RESUMO

In this contribution, we report a novel entirely photocontrolled nanoplatform comprising a binary mixture of pluronic copolymers capable of self-assembling into core-shell micelles and co-entrapping two photoactivatable components: a benzoporphyrin photosensitizer for photodynamic therapy (PDT) and coumarin-photocaged chemotherapeutic agent Chlorambucil (CAB). The resulting supramolecular micellar assembly is about 30 nm in diameter with a polydispersity index <0.1, stable for more than 72 h, and exhibits excellent preservation of the photochemical properties of the two photoresponsive components, even though they are confined within the same host nanocarrier. Appropriate regulation of the relative concentrations of these components makes them capable of absorbing visible light in comparable amounts, leading to effective simultaneous photogeneration of singlet oxygen and photo-triggered release of CAB. This "on demand" release of cytotoxic combinations results in amplified anticancer activity against MCF-7 human breast adenocarcinoma cells.


Assuntos
Antineoplásicos/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Fármacos Fotossensibilizantes/química , Oxigênio Singlete/química , Antineoplásicos/química , Antineoplásicos/farmacocinética , Humanos , Células MCF-7 , Micelas , Fotoquimioterapia
9.
Photochem Photobiol ; 91(3): 518-25, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25644689

RESUMO

Aluminum Chloride Phthalocyanine (AlPcCl) can be used as a photosensitizer (PS) for Photodynamic Inactivation of Microorganisms (PDI). The AlPcCl showed favorable characteristics for PDI due to high quantum yield of singlet oxygen (ΦΔ ) and photostability. Physicochemical properties and photodynamic inactivation of AlPcCl incorporated in polymeric micelles of tri-block copolymer (P-123 and F-127) against microorganisms Staphylococcus aureus, Escherichia coli and Candida albicans were investigated in this work. Previously, it was observed that the AlPcCl undergoes self-aggregation in F-127, while in P-123 the PS is in a monomeric form suitable for PDI. Due to the self-aggregation of AlPcCl in F-127, this formulation did not show any effect on these microorganisms. On the other hand, AlPcCl formulated in P-123 was effective against S. aureus and C. albicans and the death of microorganisms was dependent on the PS concentration and illumination time. Additionally, it was found that the values of PS concentration and illumination time to eradicate 90% of the initial population of microorganisms (IC90 and D90 , respectively) were small for the AlPcCl in P-123, showing the effectiveness of this formulation for PDI.


Assuntos
Candida albicans/efeitos dos fármacos , Indóis/química , Micelas , Viabilidade Microbiana/efeitos dos fármacos , Compostos Organometálicos/química , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacologia , Poloxâmero/análogos & derivados , Poloxâmero/química , Staphylococcus aureus/efeitos dos fármacos , Cloreto de Alumínio , Luz , Fármacos Fotossensibilizantes/efeitos da radiação , Poloxâmero/farmacologia , Staphylococcus aureus/efeitos da radiação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA