RESUMEN
The synthesis and application of gold nanoparticles (AuNPs) have attracted much attention due to their interesting optical and chemical properties, as well as their utility in imaging, therapeutics, sensors, electronics, and catalysis. AuNPs are synthesized using multiple approaches, followed by chemical modification or encapsulation, to enhance their colloidal stability, biocompatibility, and targeting. Here, we report the one-step synthesis of gold-polyester nanoparticles for use as an imaging agent. The AuNPs were prepared inside polymeric NPs by means of ultraviolet irradiation of a gold salt in the presence of Irgacure I-2959 photoinitiator. We monitored the kinetic growth and nucleation of AuNPs (in vitro and ex vivo) over time using spectral analysis. Moreover, we investigated the cytotoxicity, localized plasmonic surface resonance (LSPR), and cellular imaging capabilities of the Au-polyester nanoparticles. The resulting Au-polyester NPs were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), dynamic light scattering (DLS), and transmission electron microscopy (TEM) to probe their chemical structure, size, zeta potential (ζ), and morphology, respectively. Furthermore, in vitro experiments showed that the NP formulation is stable over time and exhibits negligible toxicity against 3T3 fibroblast and U-87 MG glioblastoma cells. The results also demonstrated that the Au-polyester NPs exhibit excellent cellular imaging properties. This one-step strategy goes beyond current syntheses of gold-polyester nanoparticles because it can be used to synthesize the imaging agent in situ (i.e., in living cells) in lieu of conventional ex situ approaches.
Asunto(s)
Oro , Nanopartículas del Metal , Poliésteres , Células 3T3 , Animales , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Dispersión Dinámica de Luz , Oro/administración & dosificación , Oro/química , Oro/efectos de la radiación , Humanos , Nanopartículas del Metal/administración & dosificación , Nanopartículas del Metal/química , Nanopartículas del Metal/efectos de la radiación , Nanopartículas del Metal/ultraestructura , Ratones , Microscopía Confocal , Microscopía Electrónica de Transmisión , Microscopía Fluorescente , Poliésteres/administración & dosificación , Poliésteres/química , Poliésteres/efectos de la radiación , Propano/análogos & derivados , Propano/química , Propano/efectos de la radiación , Células RAW 264.7 , Espectroscopía Infrarroja por Transformada de Fourier , Rayos Ultravioleta , Difracción de Rayos XRESUMEN
Pulmonary delivery is a highly attractive alternative to injections for biologics such as therapeutic proteins. However, bioavailabilities generally suffer from the presence of phagocytic cells that clear particulate matter entering the lung. In this study, microgel particles were developed using an all-aqueous two-phase system approach and evaluated for their efficacy as an inhalable controlled release system. Norbornene- and thiol-modified four- and eight-armed polyâ¯(ethylene glycol) with an average molecular mass of 10,000â¯Da were prepared as macromonomers for microgel formation. Emulsions of precursor solution droplets containing macromonomers and Irgacureâ¯2959 as photocatalyst were prepared in a dextran solution. Irradiation with UV light was used to covalently crosslink the droplets by triggering the thiol-ene reaction. The resulting microgels were processed to dry powder inhaler formulations, and respirable aerodynamic sizes were assessed in vitro. Microgels were loaded with the model proteins lysozyme and bovine serum albumin, with encapsulation efficiencies of 51.5% and 73.6%, respectively. Depending on the macromonomer type, protein-loaded microgels released their cargo over a 6-14 day period. In an MTT assay, the particles did not show significant cytotoxicity, and their recognition by alveolar macrophages was considerably lower than for polystyrene control particles. This makes the microgels a promising pulmonary delivery system for proteins and other biologics.
Asunto(s)
Hidrogeles/administración & dosificación , Microesferas , Muramidasa/administración & dosificación , Polietilenglicoles/administración & dosificación , Albúmina Sérica Bovina/administración & dosificación , Administración por Inhalación , Animales , Línea Celular , Preparaciones de Acción Retardada/administración & dosificación , Preparaciones de Acción Retardada/química , Hidrogeles/química , Pulmón/metabolismo , Macrófagos Alveolares/efectos de los fármacos , Macrófagos Alveolares/metabolismo , Ratones , Muramidasa/química , Fagocitosis , Polietilenglicoles/química , Propano/administración & dosificación , Propano/análogos & derivados , Propano/química , Propano/efectos de la radiación , Albúmina Sérica Bovina/química , Rayos UltravioletaRESUMEN
Polymerization reactions conducted inside cells must be compatible with the complex intracellular environment, which contains numerous molecules and functional groups that could potentially prevent or quench polymerization reactions. Here we report a strategy for directly synthesizing unnatural polymers in cells through free radical photopolymerization using a number of biocompatible acrylic and methacrylic monomers. This offers a platform to manipulate, track and control cellular behaviour by the in cellulo generation of macromolecules that have the ability to alter cellular motility, label cells by the generation of fluorescent polymers for long-term tracking studies, as well as generate a variety of nanostructures within cells. It is remarkable that free radical polymerization chemistry can take place within such complex cellular environments. This demonstration opens up a multitude of new possibilities for how chemists can modulate cellular function and behaviour and for understanding cellular behaviour in response to the generation of free radicals.
Asunto(s)
Radicales Libres/química , Polimerizacion/efectos de la radiación , Ácidos Polimetacrílicos/síntesis química , Poliestirenos/síntesis química , Acrilatos/química , Acrilatos/efectos de la radiación , Acrilatos/toxicidad , Citoesqueleto de Actina/efectos de los fármacos , Compuestos de Anilina/química , Compuestos de Anilina/efectos de la radiación , Compuestos de Anilina/toxicidad , Movimiento Celular/efectos de los fármacos , Fluorescencia , Células HeLa , Humanos , Metacrilatos/química , Metacrilatos/efectos de la radiación , Metacrilatos/toxicidad , Propano/análogos & derivados , Propano/química , Propano/efectos de la radiación , Fase S/efectos de los fármacos , Estirenos/química , Estirenos/efectos de la radiación , Estirenos/toxicidad , Rayos Ultravioleta , Compuestos de Vinilo/química , Compuestos de Vinilo/efectos de la radiación , Compuestos de Vinilo/toxicidadRESUMEN
In this study we explore the preparation of core-crosslinked micelles of linear-dendritic methoxy-poly(ethylene glycol) (MPEG)-co-poly(ester-sulfide) (PES) polymers to improve the stability of such polymeric micelle systems against premature disintegration and drug release. A series of MPEG-PES copolymers were synthesised via stepwise reactions of acetylation and thiol-ene photoreaction. Surface tension measurement showed that the copolymers with ethenyl surface groups could self-associate in dilute aqueous solutions to form micelles. Crosslinking within the micelle cores in the presence of dithioerythritol (DTT) linker was initiated under UV radiation. The formation of core-crosslinked micelles was confirmed by HPLC in combination with charged aerosol detection (CAD). The copolymers were found to readily hydrolyse under acidic conditions due to the ester-containing dendrons. Drug solubilisation capacities of the micellar solutions were determined using griseofulvin as a poorly water-soluble model drug. The solubility of griseofulvin showed a 10-fold enhancement in 1% w/v micelle solution and increased with the concentration of the copolymers. Drug release studies indicated that a more sustained release of griseofulvin was achieved for the core-crosslinked micelles compared to the non-crosslinked micelles, attributable to greater stability of the crosslinked core structure. The findings of this study present a new pathway towards developing biodegradable polymeric nanocarriers.
Asunto(s)
Dendrímeros/química , Micelas , Poliésteres/química , Polietilenglicoles/química , Reactivos de Enlaces Cruzados/química , Reactivos de Enlaces Cruzados/efectos de la radiación , Dendrímeros/efectos de la radiación , Ditioeritritol/química , Ditioeritritol/efectos de la radiación , Liberación de Fármacos , Griseofulvina/química , Poliésteres/efectos de la radiación , Polietilenglicoles/efectos de la radiación , Propano/análogos & derivados , Propano/química , Propano/efectos de la radiación , Solubilidad , Rayos UltravioletaRESUMEN
pH-Degradable PVA nanogels, which are prepared by photo-crosslinking thermo-preinduced PVA nanoaggregates in water without any surfactants or toxic organic solvents, are used for intracellular PTX release and anticancer treatment. These nanogels fast degraded at mildly acidic conditions with a pH-triggered PTX release, and the degradation products are only native PVA and poly(hydroxyethyl acrylate) (PHEA) as well as acetaldehyde without any toxic byproducts. The nanogel sizes could be tailored by different temperatures during the crosslinking process. The results of confocal microscopy and flow cytometry revealed that smaller nanogels exhibited enhanced internalization with MCF-7 cells than the ones treated with larger nanogels, by which the smaller PTX-loaded nanogels induced a more significant cytotoxicity against MCF-7 cells. GRAPHIC ABSTRACT: pH-Degradable PVA nanogels can be prepared by photo-crosslinking of thermo-preinduced nanoaggregates with tailored nanogel sizes given their pH-triggered PTX release and fast acid-degradation into native PVA and cell-compatible poly(hydroxyethyl acrylate) (PHEA) as well as acetaldehyde.
Asunto(s)
Sistemas de Liberación de Medicamentos , Nanoestructuras , Ácidos Polimetacrílicos , Alcohol Polivinílico , Células A549 , Antineoplásicos Fitogénicos/administración & dosificación , Antineoplásicos Fitogénicos/química , Bencenosulfonatos/química , Bencenosulfonatos/efectos de la radiación , Supervivencia Celular/efectos de los fármacos , Preparaciones de Acción Retardada , Liberación de Fármacos , Fluoresceína-5-Isotiocianato/administración & dosificación , Fluoresceína-5-Isotiocianato/química , Colorantes Fluorescentes/administración & dosificación , Colorantes Fluorescentes/química , Geles , Humanos , Concentración de Iones de Hidrógeno , Células MCF-7 , Nanoestructuras/administración & dosificación , Nanoestructuras/química , Nanoestructuras/efectos de la radiación , Paclitaxel/administración & dosificación , Paclitaxel/química , Ácidos Polimetacrílicos/administración & dosificación , Ácidos Polimetacrílicos/química , Ácidos Polimetacrílicos/efectos de la radiación , Alcohol Polivinílico/administración & dosificación , Alcohol Polivinílico/química , Alcohol Polivinílico/efectos de la radiación , Propano/análogos & derivados , Propano/química , Propano/efectos de la radiación , Rayos UltravioletaRESUMEN
The synthesis of 5-aryl-1,3-diphenylpyrazole via the reactions of 3-aryl-2,3-epoxy-1-phenyl-1-propanone with phenylhydrazine was carried out in 69-99% yields at room temperature under ultrasound irradiation. This method provides several advantages such as operational simplicity, higher yield and environment friendly.
Asunto(s)
Ácido Clorhídrico/química , Fenilhidrazinas/química , Fenilhidrazinas/efectos de la radiación , Propano/química , Propano/efectos de la radiación , Pirazoles/síntesis química , Pirazoles/efectos de la radiación , Sonicación/métodos , Catálisis , Ácido Clorhídrico/efectos de la radiación , Dosis de RadiaciónRESUMEN
The mean size of fluorescent nanoparticles produced in a propane flame has been measured with an in-situ technique employing a femtosecond laser to excite the sample and a streak camera for time-resolved detection of the fluorescence. The time profile of the fluorescence anisotropy showed a Gaussian behaviour, typical of free rotor reorientation. By measuring its width, we estimated an average carbon particle diameter of 3.3 nm, thus confirming the existence of combustion produced nanoparticles. The technique proves to be applicable to the study of gas-phase nanoparticles, both in combustion and environmental studies.
Asunto(s)
Algoritmos , Calor , Rayos Láser , Modelos Químicos , Propano/química , Propano/efectos de la radiación , Espectrometría de Fluorescencia/métodos , Anisotropía , Simulación por ComputadorRESUMEN
Electron spin resonance measurement of gamma-ray-irradiated propane hydrates shows that the normal propyl radical withdraws hydrogen from the adjacent propane molecule through the hexagonal planes of the hydrate cage without water molecule bridging.
Asunto(s)
Hidrógeno/química , Propano/química , Espectroscopía de Resonancia por Spin del Electrón , Radicales Libres/química , Radicales Libres/efectos de la radiación , Rayos gamma , Hidrógeno/efectos de la radiación , Propano/efectos de la radiación , Temperatura , Factores de Tiempo , Agua/químicaRESUMEN
Adhesives provide a needle-free method of wound closure and do not require local anaesthetics. Polymeric adhesives have been used for about 3 decades for joining several tissues of the organism. Also, they can accomplish other tasks, such as haemostasis and the ability to seal air leakages and have the potential to serve as delivery systems. PCL was modified with 2-isocyanatoethylmethacrylate to form a macromer that was crosslinked via UV irradiation using Irgacure 2959 by CIBA as the photoinitiating agent. The characterization of the materials was accomplished by: attenuated total reflectance-Fourier transform infrared (ATR-FTIR), swelling capacity determination, evaluation of adhesive capacity (by reaction with aminated substrates) and determination of surface energy by contact angle measurement. Thermal characterization of the adhesive was performed by dynamical mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA). The morphology of PCL networks was observed using scanning electron microscopy (SEM) both after crosslinking process and following biodegradation in human plasma. The haemocompatibility of the membranes was also evaluated by thrombosis and haemolysis tests.
Asunto(s)
Materiales Biocompatibles , Isocianatos/química , Metacrilatos/química , Poliésteres/química , Propano/análogos & derivados , Adhesivos Tisulares/química , Rayos Ultravioleta , Adhesividad , Animales , Biotransformación , Coagulación Sanguínea/efectos de los fármacos , Hemólisis/efectos de los fármacos , Humanos , Isocianatos/metabolismo , Isocianatos/farmacología , Isocianatos/efectos de la radiación , Ensayo de Materiales , Metacrilatos/metabolismo , Metacrilatos/farmacología , Metacrilatos/efectos de la radiación , Microscopía Electrónica de Rastreo , Fotoquímica , Poliésteres/metabolismo , Poliésteres/farmacología , Poliésteres/efectos de la radiación , Propano/química , Propano/efectos de la radiación , Conejos , Espectroscopía Infrarroja por Transformada de Fourier , Propiedades de Superficie , Termogravimetría , Factores de Tiempo , Adhesivos Tisulares/metabolismo , Adhesivos Tisulares/farmacología , Adhesivos Tisulares/efectos de la radiación , Agua/químicaRESUMEN
The frequency distribution of clustered ionizations produced by a proton beam was measured in a nanodosimetric volume of the size of a DNA segment by means of an ion-counting nanodosimeter in the energy range from 0.4 to 3.5 MeV. In order to meet the needs of the ion-counting nanodosimeter, the accelerator's primary beam was reduced in intensity by means of Rutherford scattering. The comparison between experimental results and Monte Carlo simulations show a good agreement in the energy dependence of the mean cluster size, while the experimental cluster size distributions show a higher amount of large ionization clusters compared with those obtained with the simulations.
Asunto(s)
Daño del ADN , ADN/genética , ADN/efectos de la radiación , Modelos Químicos , Propano/química , Propano/efectos de la radiación , Protones , Radiometría/métodos , Simulación por Computador , Relación Dosis-Respuesta en la Radiación , Iones , Dosis de RadiaciónRESUMEN
In the last years, the probability of the formation of ionisation clusters by primary alpha particles at 5.4 MeV in nanometric volumes of propane (20.6 and 24.0 nm in a material of density 1.0 g cm(-3)) was studied experimentally and by Monte Carlo simulation. Calculations were performed taking into account the single electron detection efficiency of the track-nanodosimetric counter, which was estimated on the base of Monte Carlo calculations of electron transport inside the detector. Now a new evaluation of the efficiency has been performed, pointing out a value lower than previously estimated. Besides, the efficiency of the counter in resolving temporally the collected electrons has been calculated, together with its effect on the measured distribution. On the base of these evaluations, a new comparison has been performed between measurements and calculations, pointing out a better agreement than previously reported.
Asunto(s)
Partículas alfa , Modelos Químicos , Nanotecnología/métodos , Propano/química , Propano/efectos de la radiación , Radiometría/métodos , Análisis por Conglomerados , Simulación por Computador , Relación Dosis-Respuesta en la Radiación , Transferencia Lineal de Energía , Microquímica/instrumentación , Microquímica/métodos , Modelos Estadísticos , Método de Montecarlo , Dosis de Radiación , Radiación Ionizante , Distribuciones EstadísticasRESUMEN
Tissue equivalent proportional counters (TEPC) allow the measurement of the ambient dose equivalent H(*)(10) in mixed fields. IRSN has been studying the design and the response of a TEPC in terms of neutron H(*)(10). First, a cylindrical counter was filled with propane gas at a low pressure. H(*)(10) measured in monoenergetic neutron fields underestimated the reference (>50%) at low energies (< 500 keV). A small amount of (3)He was then added to the gas in order to increase the response. The underestimation observed decreased but the results (> 40%) were not totally complying with the objectives (< 20%). Finally the choice was made to improve the analysis of the microdosimetric spectra y.d(y) in order to identify the energy of the incident neutrons. The analysis allows a better estimate of H(*)(10). The aim of this article is to describe the TEPC and the effect of these methods of optimisation.
Asunto(s)
Materiales Biomiméticos/química , Materiales Biomiméticos/efectos de la radiación , Gases/química , Helio/química , Helio/efectos de la radiación , Neutrones , Radiometría/instrumentación , Carga Corporal (Radioterapia) , Relación Dosis-Respuesta en la Radiación , Diseño de Equipo , Análisis de Falla de Equipo , Isótopos/química , Propano/química , Propano/efectos de la radiación , Dosis de Radiación , Radiometría/métodos , Efectividad Biológica RelativaRESUMEN
The paper presents data for measured ionization cluster size distributions by alpha particles in tissue equivalent media and comparison with the simulated data for liquid water. The experiments were carried out with a beam of 4.6 MeV alpha particles performed in a setup called the JET Counter. The theoretically derived cluster size distributions for alphas particles were obtained using the K-means algorithm. The simulation was carried out by Monte Carlo track structure calculations using cross sections for liquid water. The first moments of cluster size distributions, derived from K-means algorithm as a function of diameter of cluster centroid, were compared with the corresponding moments derived from the experiments for nitrogen and propane targets. It was found that the ratio of the first moments for water to gas targets correlates well with the corresponding ratio of the mean free paths for primary ionization by alpha particles in the two media. It is shown that the cluster size distributions for alpha particles in water, obtained from K-means algorithm, are in agreement with the corresponding distributions measured experimentally in nitrogen or propane gas targets of nanometer sizes.
Asunto(s)
Partículas alfa , Biopolímeros/química , Biopolímeros/efectos de la radiación , Modelos Químicos , Modelos Moleculares , Radiometría/métodos , Análisis por Conglomerados , Simulación por Computador , Transferencia Lineal de Energía , Nitrógeno/química , Nitrógeno/efectos de la radiación , Propano/química , Propano/efectos de la radiación , Dosis de RadiaciónRESUMEN
The aim of this work was to study radiation and the effects of temperature on conductivity properties of polyvinyl alcohol (PVA)-based potassium hydroxide (KOH) and propylene carbonate (PC), where the ionic conduction preferentially occurs in the amorphous phase by free radicals ions through gamma-irradiation. Alkaline composite polymer electrolyte (ACPE) consisting of PVA, KOH and PC of different concentration ratios were prepared by solvent-casting technique. The ACPE were irradiated with different doses from 5 kGy up to 200 kGy. The conductivity properties of the electrolyte films were measured at different frequencies in the range 20 Hz to 1 MHz using LCR meter. The results showed that the conductivity properties were dependent on the radiation dose, temperature and the concentration of the polymer blends.
Asunto(s)
Electrólitos/efectos de la radiación , Hidróxidos/efectos de la radiación , Polímeros/efectos de la radiación , Alcohol Polivinílico/efectos de la radiación , Compuestos de Potasio/efectos de la radiación , Propano/análogos & derivados , Propano/efectos de la radiación , Temperatura , Relación Dosis-Respuesta en la Radiación , Conductividad Eléctrica , Electroquímica , Rayos gamma , HumanosRESUMEN
Further evidence on the reliability of the device called the Jet Counter (JC) for studying the formation of ionisation clusters at the nanometre level are presented. The new experimental data on the distributions of ionisation cluster size originating from a 2-10 nm size target in propane irradiated by 3.8 MeV alpha particles are described. The JC consists of a pulse-operated valve that injects an expanding jet of propane into an interaction chamber, where a sensitive volume in the form of a cylinder is created. The sensitive volume was irradiated by 3.8 MeV alpha particles. The resulting distribution of ion clusters, ranging from 2 to 10 nm in unit density gas, has been measured. A method of determining the efficiency of registration of single propane ions using an ion detector is described. A method of deconvolution of the measured to true cluster size distributions is also given. Finally, the measured cluster size distributions are compared with modelled distributions based on Monte Carlo calculations. The results for propane together with previous ones for nitrogen indicate the JC to be an efficient tool for the investigation of radiation quality at the nanometre level.
Asunto(s)
Algoritmos , Análisis de Falla de Equipo/métodos , Nanotecnología/instrumentación , Nanotubos/análisis , Propano/efectos de la radiación , Radiación Ionizante , Radiometría/instrumentación , Diseño Asistido por Computadora , Diseño de Equipo/métodos , Método de Montecarlo , Nanotecnología/métodos , Nanotubos/efectos de la radiación , Protección Radiológica/instrumentación , Protección Radiológica/métodos , Radiometría/métodos , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
Despite the importance of ionization yield formation in sub-cellular structures a few nanometres in size, with regard to radiation damage our present knowledge in this respect is almost exclusively based on Monte Carlo simulations which in turn are based on cross section sets for water vapour or liquid water. Experimental data, although urgently needed, are still missing because the direct measurement of ionization yields in sub-cellular structures or, at least, in nanometric volumes of liquid water, is not yet possible. The best feasible way to overcome this problem of measurement at present, is the use of highly sophisticated counters filled with gases at low operating pressure to simulate target volumes a few nanometres in diameter at unit density. An indispensable prerequisite of the reliability of such measurements is, however, a check of the equivalence of the ionization yield produced in a specified target gas and the yield to be expected in liquid water or biological material. For this purpose, the ionization yield formation by electrons and alpha-particles in liquid water was simulated using the Monte Carlo method and compared with that produced in propane-based tissue-equivalent gas (composition by volume 55% C3H8, 39.6% CO2, 5.4% N2). After a short summary of the most important physical aspects of ionization cluster formation, new results are presented and discussed from the point of view of radiation physics and radiation biology.