RESUMEN
In biological systems, nanoparticles interact with biomolecules, which may undergo protein corona formation that can result in noncontrolled aggregation. Therefore, comprehending the behavior and evolution of nanoparticles in the presence of biological fluids is paramount in nanomedicine. However, traditional lab-based colloid methods characterize diluted suspensions in low-complexity media, which hinders in-depth studies in complex biological environments. Here, we apply X-ray photon correlation spectroscopy (XPCS) to investigate silica nanoparticles (SiO2) in various environments, ranging from low to high complex biological media. Interestingly, SiO2 revealed Brownian motion behavior, irrespective of the complexity of the chosen media. Moreover, the SiO2 surface and media composition were tailored to underline the differences between a corona-free system from protein corona and aggregates formation. Our results highlighted XPCS potential for real-time nanoparticle analysis in biological media, surpassing the limitations of conventional techniques and offering deeper insights into colloidal behavior in complex environments.
Asunto(s)
Nanopartículas , Corona de Proteínas , Dióxido de Silicio , Dióxido de Silicio/química , Nanopartículas/química , Corona de Proteínas/química , Fotones , Coloides/química , Propiedades de SuperficieRESUMEN
The field of soft matter teems with molecules and aggregates of molecules that have internal size-modulating degrees of freedom. Proteins, peptides, microgels, polymers, micelles, and even some colloids can exist in multiple-often just two dominating-states with different effective sizes, where size can refer to the volume or to the cross-sectional area for particles residing on surfaces. The size-dependence of their accessible states renders the behavior of these particles pressure-sensitive. The Bragg-Williams model is among the most simple mean-field methods to translate the presence of inter-particle interactions into an approximate phase diagram. Here, we extend the Bragg-Williams model to account for the presence of particles that are immersed in a solvent and exist in two distinct states, one occupying a smaller and the other one a larger size. The basis of the extension is a lattice-sublattice approximation that we use to host the two size-differing states. Our model includes particle-solvent interactions that act as an effective surface tension between particles and solvent and are ignorant of the state in which the particles reside. We analyze how the energetic preference of the particles for one or the other state affects the phase diagrams. The possibility of a single phase-two phases-single phase sequence of phase transitions as a function of increasing temperature is demonstrated.
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Coloides , Micelas , Coloides/química , Polímeros/química , Temperatura , SolventesRESUMEN
Colloidal suspensions of monodisperse spherical particles have been extensively studied since one of the main advantages of these systems is their similarity to atomic ones. This property has been used successfully in basic science to understand the equilibrium and non-equilibrium behavior of model colloids and to correlate them with their atomic counterparts. In contrast, suspensions used in technological processes are usually more complex. Nevertheless, for their effective applications, it is crucial to understand their properties, such as the microstructure, dynamics, and flow behavior, as well as the mechanisms underlying their self-organization. The first step towards this knowledge is switching from monodisperse suspensions to moderately complex ones, namely binary mixtures. Therefore, the present review aims to summarize the current knowledge about the phase behavior of binary mixtures of spherical colloids with different inter-particle interactions, such as nearly hard spheres, electrostatic repulsion/attraction, depletion attraction, and attraction due to DNA hybridization. A comparison of experimental work with theoretical predictions is described for binary suspensions studied in three and two dimensions. Several open questions are outlined in the conclusions.
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Coloides , ADN , Coloides/química , Tamaño de la Partícula , SuspensionesRESUMEN
In this work, monodisperse silica-coated gold nanoparticles (NPs) were synthesized and used for obtaining aqueous colloidal dispersions with an optimum relationship between colloidal stability and photothermal activity. The idea behind this design was to produce systems with the advantages of the presence of a silica shell (biocompatibility, potential for surface modification, and protecting effect) with a minimal loss of optical and thermal properties. With this aim, the photothermal properties of NPs with silica shells of different thicknesses were analyzed under conditions of high radiation extinction. By using amorphous, gel-like silica coatings, thicknesses higher than 40 nm could be obtained without an important loss of the light absorption capacity of the colloids and with a significant photothermal response even at low NP concentrations. The effects produced by changes in the solvent and in the NP concentration were also analyzed. The results show that the characteristics of the shell control both, the photothermal effect and the optical properties of the colloidal dispersions. As the presence of a silica shell strongly enhances the possibilities of adding cargo molecules or probes, these colloids can be considered of high interest for biomedical therapies, sensing applications, remote actuation, and other technological applications.
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Nanopartículas del Metal , Nanocáscaras , Coloides/química , Oro/química , Nanopartículas del Metal/química , Dióxido de Silicio/química , SuspensionesRESUMEN
A ferrofluid with 1,2-Benzenediol-coated iron oxide nanoparticles was synthesized and physicochemically analyzed. This colloidal system was prepared following the typical co-precipitation method, and superparamagnetic nanoparticles of 13.5 nm average diameter, 34 emu/g of magnetic saturation, and 285 K of blocking temperature were obtained. Additionally, the zeta potential showed a suitable colloidal stability for cancer therapy assays and the magneto-calorimetric trails determined a high power absorption density. In addition, the oxidative capability of the ferrofluid was corroborated by performing the Fenton reaction with methylene blue (MB) dissolved in water, where the ferrofluid was suitable for producing reactive oxygen species (ROS), and surprisingly a strong degradation of MB was also observed when it was combined with H2O2. The intracellular ROS production was qualitatively corroborated using the HT-29 human cell line, by detecting the fluorescent rise induced in 2,7-dichlorofluorescein diacetate. In other experiments, cell metabolic activity was measured, and no toxicity was observed, even with concentrations of up to 4 mg/mL of magnetic nanoparticles (MNPs). When the cells were treated with magnetic hyperthermia, 80% of cells were dead at 43 °C using 3 mg/mL of MNPs and applying a magnetic field of 530 kHz with 20 kA/m amplitude.
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Coloides/química , Coloides/farmacología , Hipertermia Inducida/métodos , Nanopartículas Magnéticas de Óxido de Hierro/química , Especies Reactivas de Oxígeno/metabolismo , Catecoles/química , Línea Celular , Coloides/síntesis química , Citotoxinas/síntesis química , Citotoxinas/química , Citotoxinas/farmacología , Humanos , Concentración de Iones de Hidrógeno , Magnetismo , Microscopía Electrónica de Transmisión , Oxidantes/síntesis química , Oxidantes/química , Oxidantes/farmacología , Espectroscopía Infrarroja por Transformada de Fourier , Temperatura , Difracción de Rayos XRESUMEN
Tuberculosis is the top infectious disease worldwide and the development of a vaccine and diagnostic tools to control the disease is a priority that requires a better understanding of the factors involved in the pathogenesis of Mycobacterium tuberculosis, the infectious agent. It is known that bacterial cell surface components are released, interact with immune cell receptors, and may traffic toward host cell structures. Many of these compounds are lipids that have been associated with mycobacterial virulence. However, their hydrophobic nature has frequently hampered their biological study. In this work, silica particles were coated with functional lipids to obtain a colloidal bioinspired system based on nonhydrosoluble glycolipids. Mycobacterium tuberculosis phosphatidylinositol mannosides (PIMs), known to interact with receptors of innate immune cells, were purified from the M. tuberculosis H37Rv type strain, and used to prepare large unilamellar liposomes in combination with zwitterionic phosphatidyl choline. Then, bacillary-like Santa Barbara Amorphous-15 (SBA-15) silica particles were cationized and the vesicle fusion method was used to promote the attachment of anionic PIM-containing lipid bilayers. Thermogravimetric analysis, x-ray diffraction, N2 adsorption-desorption isotherm analysis, Fourier transform infrared spectroscopy, electron microscopy, and zeta potential analyses were used to characterize the materials obtained. The as-prepared PIM-containing colloids, named PIM@SBA-15, showed biocompatibility toward human fibroblasts and were found to colocalize with Toll-like receptor (TLR)2 upon their incubation with THP1-derived macrophages. Furthermore, the particles induced the formation of pseudopods and were internalized into phagocytic cells. In all, these data suggest the usefulness of PIM@SBA-15 particles to better comprehend the interactions between immune cells and PIMs.
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Coloides/química , Fosfatidilinositoles/química , Dióxido de Silicio/química , Materiales Biocompatibles/química , Materiales Biocompatibles/metabolismo , Materiales Biocompatibles/farmacología , Línea Celular , Supervivencia Celular/efectos de los fármacos , Humanos , Macrófagos/citología , Macrófagos/inmunología , Macrófagos/metabolismo , Mycobacterium tuberculosis/metabolismo , Fagocitosis/efectos de los fármacos , Fosfatidilinositoles/metabolismo , Porosidad , Tuberculosis/metabolismo , Tuberculosis/microbiología , Tuberculosis/patología , Liposomas Unilamelares/químicaRESUMEN
The use of noble metal nanoparticles in biomedical and biotechnological applications is nowadays well established. Particularly, silver nanoparticles (AgNPs) were proven to be effective for instance as a biocide agent. They also find applications in tumor therapies and sensing applications being encouraging tools for in-vivo imaging. In this framework, whenever they are in contact with living systems, they are rapidly coated by a protein corona thereby influencing a variety of biological events including cellular uptake, blood circulation lifetime, cytotoxicity and, ultimately, the therapeutic effect. Taking these considerations into account, we have explored the behavior of polymer-coated AgNPs in model protein environments focusing on the self-development of protein coronas. The polymers polyethyleneimine (PEI), polyvinylpyrrolidone (PVP) and poly(2-vinyl pyridine)-b-poly(ethylene oxide) (PEO-b-P2VP) were used as stabilizing agents. The chemical nature of the polymer capping remarkably influences the behavior of the hybrid nanomaterials in protein environments. The PEO-b-P2VP and PVP-stabilized AgNPs are essentially inert to the model proteins adsorption. On the other hand, the PEI-stabilized AgNPs interact strongly with bovine serum albumin (BSA). Nevertheless, the same silver colloids were evidenced to be stable in IgG and lysozyme environments. The BSA adsorption into the PEI-stabilized AgNPs is most probably driven by hydrogen bonding and van der Waals interactions as suggested by isothermal titration calorimetry data. The development of protein coronas around the AgNPs may have relevant implications in a variety of biological events. Therefore, further investigations are currently underway to evaluate the influence of its presence on the cytotoxicity, hemolytic effects and biocide properties of the produced hybrid nanomaterials.
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Coloides/química , Polímeros/química , Corona de Proteínas/química , Albúmina Sérica Bovina/química , Plata/química , Adsorción , Animales , Calorimetría , Bovinos , Pollos , Dispersión Dinámica de Luz , Nanopartículas/ultraestructura , Polietileneimina/química , Povidona/química , Espectrometría de Fluorescencia , Espectrofotometría UltravioletaRESUMEN
AIMS: To use an agroindustrial waste (orange peels) as a source of polyphenols as a reducing medium for obtaining silver nanoparticles by greener method. BACKGROUND: Several techniques have been employed for AgNPs synthesis, nevertheless, most of them involve the use of toxic chemicals in the process. The use of fungi, bacteria, and plant extracts as subtracts for green synthesis is an ecofriendly alternative, although hypothetic, route for AgNPs large scale synthesis. In the case of plant extracts, it is believed that polyphenols are the biomolecules responsible for the reduction and stabilization of the Ag+ ions into AgNPs, being a sustainable and ecological option; polyphenols could be obtained from plant waste and agroindustrial subproducts. OBJECTIVE: To develop an efficient, greener, and low-cost method of AgNPs production using natural products. METHODS: The basic principle of silver nanoparticles synthesis is the interaction in a mixture of silver nitrate (source of Ag+ ions) and the orange peel extract (reducing and stabilizing agent) under certain conditions. Five treatments were carried out, evaluating several parameters during AgNPs synthesis such as pH, orange peel extract-silver nitrate ratio, time and conditions of incubation, irradiation of UV light, irradiation of microwave, and temperature. RESULT: The synthesis of silver nanoparticles from an agroindustrial waste as the orange peel was successfully carried out and checked by visual evaluation, UV-Vis spectroscopy, and EDS analysis. The particle size was estimated between 42.82 nm to 151.75 nm, having a spherical and ovoid morphology. DISCUSSION: Through the analysis of several synthesis conditions, it has become possible to establish a suitable treatment to increase antibacterial yield and evaluate morphology and size traits in order to acquire the best conditions for a future industrial scale synthesis. CONCLUSION: The orange peel aqueous extract resulted as a great source of polyphenols, allowing the successful synthesis of silver nanoparticles in mild conditions. Thus, obtained AgNPs revealed an increased antibacterial effect and potential against Gram-positive bacteria such as Staphyloccocus aureus.
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Antibacterianos/farmacología , Citrus sinensis/química , Tecnología Química Verde , Nanopartículas del Metal/química , Plata/farmacología , Coloides/química , Bacterias Grampositivas/efectos de los fármacos , Nanopartículas del Metal/ultraestructura , Pruebas de Sensibilidad Microbiana , Soluciones , Espectrometría por Rayos X , Espectrofotometría Ultravioleta , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
BACKGROUND: The incorporation of hydrocolloids into starch dispersions modifies their techno-functional properties, such as gelatinization, retrogradation, syneresis, and texture, among others. Their main function is to improve these properties and to promote greater stability of starch gels. Thus, the main objective of this study was to evaluate the effect of adding colloids (guar gum and xanthan gum) on the texture properties (hardness, elasticity, cohesiveness, and gumminess) and syneresis of the starch gels made from the common variety of arrowroot. Analysis of variance (ANOVA) and regression were carried out to analyze the effects of the treatments and variables with their respective interactions. RESULTS: The addition of guar gum and xanthan gum influenced the stability of the starch gels studied, and it was capable of reducing syneresis even at low concentrations, with a greater effect for xanthan gum. Both gums were capable of inhibiting syneresis at concentrations above 0.5%, throughout the storage time studied (5 days). The addition of these hydrocolloids was also shown to influence the following texture parameters: hardness, cohesiveness, and gumminess, but showed no effect on gel elasticity. CONCLUSION: The addition of hydrocolloids was shown to be an alternative way of increasing the stability and enhancing the textural properties of the starch gels in arrowroot. © 2020 Society of Chemical Industry.
Asunto(s)
Galactanos/química , Mananos/química , Marantaceae/química , Extractos Vegetales/química , Gomas de Plantas/química , Polisacáridos Bacterianos/química , Almidón/química , Coloides/química , Elasticidad , Geles/química , Dureza , ReologíaRESUMEN
BACKGROUND: The biodegradable and biocompatible nature of pectin-based films is of particular interest in wound dressing applications, due to its non-toxicity, pH-sensitivity and gelling activity. An approach to improve the mechanical properties, the release profile of bioactive compounds as well as the performance in wet environments of pectin-based films is mixing with other biopolymers. OBJECTIVE: To prepare hydrocolloid films based on crosslinked pectin / starch blend loaded with bioactive extracts from leaves of G. tinctoria and U. molinae with controlled release of bioactive compounds and healing property. METHODS: The hydrocolloid films were characterized by FTIR, SEM, and TGA-FTIR techniques and their tensile properties, water uptake, and polyphenolic release profile in aqueous media were evaluated. The dermal anti inflammatory activity of the hydrocolloid films was assessed by the mouse ear inflammation test. The wound healing property of the loaded hydrocolloid films was explored in a rat model and in a clinical trial (sacrum pressure ulcer). RESULTS: The films showed an adequate water-uptake capacity between 100-160%. The release of active compounds from the hydrocolloid films followed the Korsmeyer-Peppas equation. The mechanical properties of hydrocolloid films were not affected by the plant extracts within the concentration range used. The incorporation of the bioactive extracts in the polysaccharide films inhibited the topical edematous response by about 50%. The topical application of the loaded hydrocolloid film on the pressure ulcer is completely closed after 17 days without showing any adverse reaction. CONCLUSION: A novel hydrocolloid matrix was produced from crosslinked starch-pectin, which exhibited suitable chemical-physical properties to be used as a carrier of plant extracts with wound healing properties.
Asunto(s)
Antiinflamatorios/farmacología , Reactivos de Enlaces Cruzados/farmacología , Pectinas/farmacología , Extractos Vegetales/farmacología , Úlcera por Presión/tratamiento farmacológico , Almidón/farmacología , Cicatrización de Heridas/efectos de los fármacos , Anciano , Animales , Antiinflamatorios/química , Vendajes , Coloides/química , Coloides/farmacología , Reactivos de Enlaces Cruzados/química , Femenino , Humanos , Magnoliopsida/química , Masculino , Ratones , Ratones Endogámicos , Myrtaceae/química , Pectinas/química , Extractos Vegetales/química , Hojas de la Planta/química , Úlcera por Presión/patología , Ratas , Ratas Sprague-Dawley , Almidón/químicaRESUMEN
Colloidal Liquid Aphrons (CLAs) are micron sized discrete spherical solvent droplets formed by the dispersion of polyaphrons into a bulk aqueous phase at a low phase volume ratio where they can be kept homogenously suspended with only minimal agitation. CLAs have high stability due to the presence of a surfactant 'shell' surrounding the solvent core, and possess large surface areas per unit volume for mass transfer due to their small size. Therefore, CLAs are well suited for applications in pre-dispersed solvent extraction (PSE), enzyme immobilization, and have the potential to be used as a drug delivery system. Using PSE, CLAs have been used to remove metals such as Ni2+, Cu2+, Fe3+, Cr3+ and Mg2+ from dilute streams, separate organic dyes such as Yellow 1 from wastewater, extract succinic and lactic acid, reactively extract phenylalanine, and separate suspensions. CLAs have also been used to immobilize enzymes such as lipase, lysozyme and albumins with cases of superactivity being reported due to the influence of surfactant and solvent interactions with the enzyme. Furthermore, due to their similarity to current drug delivery systems such as microemulsions and hydrogels, and other advantages, CLA systems have the potential to be adapted for drug delivery systems also. This article provides a complete list of the current applications of Colloidal Liquid Aphrons (CLAs) in PSE and enzyme immobilization, and also presents insight into how CLAs can be utilized as a drug delivery method in the future. Finally, this review ends by summarizing potentially interesting research areas to pursue in this field.
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Albúminas/química , Sistemas de Liberación de Medicamentos , Enzimas Inmovilizadas/química , Lipasa/química , Muramidasa/química , Coloides/química , Coloides/aislamiento & purificación , Coloides/metabolismo , Enzimas Inmovilizadas/metabolismo , Lipasa/metabolismo , Muramidasa/metabolismo , Tamaño de la Partícula , Solventes/química , Propiedades de SuperficieRESUMEN
Atomic force microscopy rheological measurements (Rheo-AFM) of the linear viscoelastic properties of single, charged colloids having a star-like architecture with a hard core and an extended, deformable double-stranded DNA (dsDNA) corona dispersed in aqueous saline solutions are reported. This is achieved by analyzing indentation and relaxation experiments performed on individual colloidal particles by means of a novel model-free Fourier transform method that allows a direct evaluation of the frequency-dependent linear viscoelastic moduli of the system under investigation. The method provides results that are consistent with those obtained via a conventional fitting procedure of the force-relaxation curves based on a modified Maxwell model. The outcomes show a pronounced softening of the dsDNA colloids, which is described by an exponential decay of both the Young's and the storage modulus as a function of the salt concentration within the dispersing medium. The strong softening is related to a critical reduction of the size of the dsDNA corona, down to ≈70% of its size in a salt-free solution. This can be correlated to significant topological changes of the dense star-like polyelectrolyte forming the corona, which are induced by variations in the density profile of the counterions. Similarly, a significant reduction of the stiffness is obtained by increasing the length of the dsDNA chains, which we attribute to a reduction of the DNA density in the outer region of the corona.
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Coloides/química , ADN/química , Elasticidad , Microscopía de Fuerza Atómica , Reología , Módulo de Elasticidad , Sales (Química)/química , Factores de Tiempo , ViscosidadRESUMEN
Latex extracted from Hevea brasiliensis tree has been used as a green alternative for preparing gold nanoparticles (Au NPs); however, no study evaluating the cytotoxic and genotoxic potential of Au NPs synthesised using H. brasiliensis has been published. The present study aimed to synthesise and characterise colloidal Au NPs using latex from H. brasiliensis and to evaluate their in vitro cytotoxicity and genotoxicity. Ideal conditions for the green synthesis of Au NPs were studied. In vitro cytotoxicity and genotoxicity of Au NPs in CHO-K1 cells was also evaluated. Our findings indicated that the ideal synthesis conditions of pH, temperature, reduction time, and concentrations of latex and HAuCl4 were 7.0, 85°C, 120â min, 3.3â mg/mL, and 5.0â mmol/L, respectively. LC5024â h of Au NPs was 119.164 ± 5.31â µg/mL. Lowest concentration of Au NPs tested presented minimal cytotoxicity and genotoxicity. However, high concentrations of Au NPs promoted DNA damage and cell death via apoptosis. On the basis of these findings, the authors optimised the use of an aqueous solution of H. brasiliensis latex as a reducing/stabilising agent for the green synthesis of Au NPs. Low concentrations of these NPs are biocompatible in normal cell types, suggesting that these NPs may be used in biological applications.
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Coloides/química , Oro/química , Tecnología Química Verde , Hevea/química , Látex/química , Nanopartículas del Metal/química , Animales , Apoptosis , Células CHO , Pruebas de Carcinogenicidad , Supervivencia Celular , Cricetinae , Cricetulus , Daño del ADN , Concentración de Iones de Hidrógeno , Pruebas de Mutagenicidad , TemperaturaRESUMEN
Oxidative stress plays an essential role in the pathogenesis and progression of inflammatory bowel disease. Co-administration of antioxidants and anti-inflammatory drugs has shown clinical benefits. Due to its significant reactive oxygen species (ROS) scavenging ability, great interest has been focused on superoxide dismutase (SOD) for therapeutic use. However, oral SOD is exposed to biochemical degradation along gastrointestinal transit. Furthermore, the antioxidant activity of SOD must be achieved intracellularly, therefore its cell entry requires endocytic mediating mechanisms. In this work, SOD was loaded into nanoarchaeosomes (ARC-SOD), nanovesicles fully made of sn 2,3 ether linked phytanyl saturated archaeolipids to protect and target SOD to inflammatory macrophages upon oral administration. Antioxidant and anti-inflammatory activities of ARC-SOD, non-digested and digested in simulated gastrointestinal fluids, on macrophages stimulated with H2O2 and lipopolysaccharide were determined and compared with those of free SOD and SOD encapsulated into highly stable liposomes (LIPO-SOD). Compared to SOD and LIPO-SOD, ARC-SOD (170 ± 14 nm, -30 ± 4 mV zeta potential, 122 mg protein/g phospholipids) showed the highest antioxidant and anti-inflammatory activity: it reversed the cytotoxic effect of H2O2, decreased intracellular ROS and completely suppressed the production of IL-6 and TNF-α on stimulated J774 A.1 cells. Moreover, while the activity of LIPO-SOD was lost upon preparation, gastrointestinal digestion and storage, ARC-SOD was easy to prepare and retained its antioxidant capacity upon digestion in simulated gastrointestinal fluids and after 5 months of storage. Because of their structural and pharmacodynamic features, ARC-SOD may be suitable for oral targeted delivery of SOD to inflamed mucosa.
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Archaea/química , Sistemas de Liberación de Medicamentos , Inflamación/patología , Macrófagos/patología , Nanopartículas/química , Superóxido Dismutasa/metabolismo , Animales , Antiinflamatorios/farmacología , Células CACO-2 , Bovinos , Muerte Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Coloides/química , Humanos , Concentración de Iones de Hidrógeno , Lipopolisacáridos/farmacología , Liposomas , Macrófagos/efectos de los fármacos , Ratones , Estrés Oxidativo/efectos de los fármacos , Sustancias Protectoras/farmacología , Especies Reactivas de Oxígeno/metabolismo , Colato de Sodio/análisisRESUMEN
It is estimated that over 100 million people have been infected with human immunodeficiency virus (HIV-1) resulting in approximately 30 million deaths globally. Herein, we designed and developed novel nano-immunoconjugates using gold nanoparticles (AuNPs) and carboxymethylcellulose (CMC) biopolymer, which performed simultaneously as an eco-friendly in situ reducing agent and surface stabilizing ligand for the aqueous colloidal process. These AuNPs-CMC nanocolloids were biofunctionalized with the gp41 glycoprotein receptor (AuNPs-CMC-gp41) or HIV monoclonal antibodies (AuNPs-CMC_PolyArg-abHIV) for detection using the laser light scattering immunoassay (LIA). These AuNPs-CMC bioengineered nanoconjugates were extensively characterized by morphological and physicochemical methods, which demonstrated the formation of spherical nanocrystalline colloidal AuNPs with the average size from 12 to 20 nm and surface plasmon resonance peak at 520 nm. Thus, stable nanocolloids were formed with core-shell nanostructures composed of AuNPs and biomacromolecules of CMC-gp41, which were cytocompatible based on in vitro cell viability results. The AuNPs-CMC-gp41 nanoconjugates were tested against HIV monoclonal antibodies conjugates (AuNPs-CMC_PolyArg-abHIV) using the light scattering immunoassay (LIA) where they behaved as active nanoprobes for the detection at nM level of HIV-1 antigenic proteins. This strategy offers a novel nanoplatform for creating bioprobes using green nanotechnology for the detection of HIV-1 and other virus-related diseases.
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Carboximetilcelulosa de Sodio/química , Oro/química , VIH-1/aislamiento & purificación , Inmunoensayo , Rayos Láser , Nanopartículas/química , Anticuerpos Monoclonales/inmunología , Línea Celular Tumoral , Supervivencia Celular , Coloides/química , Oro/inmunología , Células HEK293 , VIH-1/inmunología , Humanos , Conformación Molecular , Tamaño de la Partícula , Propiedades de SuperficieRESUMEN
Opuntia monacantha mucilage was investigated for its physicochemical characteristics and functional properties. The mucilage extraction yield was 12% (DW) and it consisted of 80.12% carbohydrates, 15.14% ashes, 3.55% proteins, and 1.19% lipids. Monosaccharide profiling demonstrated a predominantly presence of galactose, glucuronic acid, and arabinose. Viscosimetric measurements gave an intrinsic viscosity of 9.02â¯dL/g and a molar mass of 1.12â¯×â¯106â¯g/mol. Reconstituted mucilage solution (1% w/v) had a mean particle diameter (D4,3) of 648â¯nm and solubility above 85%. Its emulsifying capacity improved with the increment of mucilage solution in the emulsion; likewise, it provided high emulsion stability through different ratios of oil to polysaccharide solution. It displayed good foaming capacity, although its foam stability progressively reduced over time. In addition, its blending with ovalbumin resulted in a foaming capacity enhancement and in a markedly greater foam stability compared to ovalbumin alone. The rheological studies indicated the mucilage solutions exhibited shear-thinning behavior at concentrations between 1 and 10% and fairly stable viscous properties in the temperature range of 5-80⯰C. These outcomes support that O. monacantha mucilage may find potentially useful applications in food systems, particularly as an emulsifying, foaming and thickening agent, or as a stabilizer.
Asunto(s)
Fenómenos Químicos , Coloides/química , Opuntia/química , Mucílago de Planta/química , Emulsiones , Tamaño de la Partícula , Polvos , Solubilidad , Soluciones , Temperatura , ViscosidadRESUMEN
Magnetic hyperthermia is an oncological therapy where magnetic nanostructures, under a radiofrequency field, act as heat transducers increasing tumour temperature and killing cancerous cells. Nanostructure heating efficiency depends both on the field conditions and on the nanostructure properties and mobility inside the tumour. Such nanostructures are often incorrectly bench-marketed in the colloidal state and using field settings far off from the recommended therapeutic values. Here, we prepared nanoclusters composed of iron oxide magnetite nanoparticles crystallographically aligned and their specific absorption rate (SAR) values were calorimetrically determined in physiological fluids, agarose-gel-phantoms and ex vivo tumours extracted from mice challenged with B16-F0 melanoma cells. A portable, multipurpose applicator using medical field settings; 100 kHz and 9.3 kA m-1, was developed and the results were fully analysed in terms of nanoclusters' structural and magnetic properties. A careful evaluation of the nanoclusters' heating capacity in the three milieus clearly indicates that the SAR values of fluid suspensions or agarose-gel-phantoms are not adequate to predict the real tissue temperature increase or the dosage needed to heat a tumour. Our results show that besides nanostructure mobility, perfusion and local thermoregulation, the nanostructure distribution inside the tumour plays a key role in effective heating. A suppression of the magnetic material effective heating efficiency appears in tumour tissue. In fact, dosage had to be increased considerably, from the SAR values predicted from fluid or agarose, to achieve the desired temperature increase. These results represent an important contribution towards the design of more efficient nanostructures and towards the clinical translation of hyperthermia.
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Óxido Ferrosoférrico/química , Hipertermia Inducida , Melanoma Experimental/terapia , Nanopartículas/química , Sefarosa/química , Animales , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Coloides/química , Microscopía por Crioelectrón , Femenino , Magnetismo , Melanoma Experimental/diagnóstico , Melanoma Experimental/diagnóstico por imagen , Ratones , Ratones Endogámicos C57BL , Método de Montecarlo , Nanopartículas/metabolismo , Nanopartículas/toxicidad , Fantasmas de Imagen , TemperaturaRESUMEN
The use of colloidal particles as drug delivery carriers holds a great promise in terms of improvement of traditional treatment and diagnosis of human diseases. Nano- and microsized particles of a different composition including organic and inorganic materials can be fabricated with a great control over size, shape and surface properties. Nevertheless, only some few formulations have surpassed the benchtop and reached the bedside. The principal obstacle of colloidal drug delivery systems is their poor accumulation in target tissues, organs and cells, mainly by efficient sequestration and elimination by the mononuclear phagocytic system. Recent evidence suggests that, besides size, the surface character of colloidal systems is the most determinant design parameter that may ultimately guarantee successful biological performance. To approach these issues, materials designers and engineers can make use of multiple strategies and tools to finely modulate the particles' surface towards highly efficient and biocompatible materials. In this article, we provide an overview of the most relevant colloidal drug delivery systems, a summary of the available literature regarding the effects of surface charge, hydrophobicity and softness on biological response, and finally, we review the key points of surface modification strategies with organic, inorganic and biological materials.
Asunto(s)
Coloides/química , Sistemas de Liberación de Medicamentos , Preparaciones Farmacéuticas/química , Animales , Electroquímica , HumanosRESUMEN
Bacteria-synthesized polysaccharides have attracted interest for biomedical applications as promising biomaterials to be used as implants and scaffolds. The present study tested the hypothesis that cellulose exopolysaccharide (CEC) produced from sugarcane molasses of low cost and adequate purity would be suitable as a template for 2D and 3D neuron and/or astrocyte primary cultures, considering its low toxicity. CEC biocompatibility in these primary cultures was evaluated with respect to cell viability, adhesion, growth and cell function (calcium imaging). Polystyrene or Matrigel® matrix were used as comparative controls. We demonstrated that the properties of this CEC in the 2D or 3D configurations are suitable for differentiation of cortical astrocytes and neurons in single or mixed cultures. No toxicity was detected in neurons that showed NMDA-induced Ca2+ influx. Unlike other polysaccharides of bacterial synthesis, the CEC was efficient as a support even in the absence of surface conjugation with extracellular matrix proteins, maintaining physiological characteristics of cultured neural cells. These observations open up the perspective for development of a novel 3D biofunctional scaffold produced from bacterial cellulose and obtained from renewable sources whose residues are not pollutants. Its low cost and possibility to be manufactured in scale are also suitable for potential applications in regenerative medicine.
Asunto(s)
Astrocitos/citología , Neuronas/patología , Polisacáridos/química , Cultivo Primario de Células , Saccharum/química , Animales , Materiales Biocompatibles , Calcio/química , Adhesión Celular , Proliferación Celular , Supervivencia Celular , Células Cultivadas , Coloides/química , Matriz Extracelular/metabolismo , Femenino , Hidrogeles/química , Imagenología Tridimensional , Inmunohistoquímica , Melaza , N-Metilaspartato/química , Neuronas/metabolismo , Ratas , Ratas Wistar , Estrés Mecánico , Ingeniería de Tejidos/métodosRESUMEN
BACKGROUND: Microcapsules fabricated using layer-by-layer self-assembly have unique properties, making them attractive for drug delivery applications. The technique has been improved, allowing the deposition of multiple layers of oppositely charged polyelectrolytes on spherical, colloidal templates. These templates can be decomposed by coating multiple layers, resulting in hollow shells. In this paper, we describe a novel drug delivery system for loading photosensitizer drugs into hollow multilayered microcapsules for photoprocess applications. METHODS: Manganese carbonate particles were prepared by mixing NH4HCO3 and MnSO4 and performing consecutive polyelectrolyte adsorption processes onto these templates using poly-(sodium 4-styrene sulfonate) and poly-(allylamine hydrocholoride). A photosensitizer was also incorporated into the layers. Hollow spheres were fabricated by removing the cores in the acidic solution. The hollow, multilayered microcapsules were studied by scanning electron microscopy, steady-state, and time-resolved techniques. Their biological activity was evaluated in vitro with cancer cells using a conventional MTT assay. RESULTS: The synthesized CaCO3 microparticles were uniform, non-aggregated, and highly porous spheres. The phthalocyanine derivatives loaded in the microcapsules maintained their photophysical behaviour after encapsulation. The spectroscopic results presented here showed excellent photophysical behaviour of the studied drug. We observed a desirable increase in singlet oxygen production, which is favourable for the PDT protocol. Cell viability after treatment was determined and the proposed microcapsules caused 80% cell death compared to the control. CONCLUSIONS: The results demonstrate that photosensitizer adsorption into the CaCO3 microparticle voids together with the layer-by-layer assembly of biopolymers provide a method for the fabrication of biocompatible microcapsules for use as biomaterials.