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N-Acetylgalactosamine-6-sulfatase (GALNS) is an enzyme whose deficiency is related to the lysosomal storage disease Morquio A. For the development of effective therapeutic approaches against this disease, the design of suitable enzyme enhancers (i.e. pharmacological chaperones) is fundamental. The natural substrates of GALNS are the glycosaminoglycans keratan sulfate and chondroitin 6-sulfate, which mainly display repeating units of sulfated carbohydrates. With a biomimetic approach, gold nanoparticles (AuNPs) decorated with simple monosaccharides, sulfated ligands (homoligand AuNPs), or both monosaccharides and sulfated ligands (mixed-ligand AuNPs) were designed here as multivalent inhibitors of GALNS. Among the homoligand AuNPs, the most effective inhibitors of GALNS activity are the ß-D-galactoside-coated AuNPs. In the case of mixed-ligand AuNPs, ß-D-galactosides/sulfated ligands do not show better inhibition than the ß-D-galactoside-coated AuNPs. However, a synergistic effect is observed for α-D-mannosides in a mixed-ligand coating with sulfated ligands that reduced IC50 by one order of magnitude with respect to the homoligand α-D-mannoside-coated AuNPs. SAXS experiments corroborated the association of GALNS with ß-D-galactoside AuNPs. These AuNPs are able to restore the enzyme activity by almost 2-fold after thermal denaturation, indicating a potential chaperoning activity towards GALNS. This information could be exploited for future development of nanomedicines for Morquio A. The recent implications of GALNS in cancer and neuropathic pain make these kinds of multivalent bionanomaterials of great interest towards multiple therapies.
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Condroitina Sulfatases , Nanopartículas Metálicas , Ouro , Acetilgalactosamina , Monossacarídeos , Ligantes , Sulfatos , Espalhamento a Baixo Ângulo , Difração de Raios X , LisossomosRESUMO
An approach for reducing toxicity and enhancing therapeutic potential of supramolecular polyamine phosphate nanoparticles (PANs) through PEGylation of polyamines before their assembly into nanoparticles is presented here. It is shown that the number of polyethylene glycol (PEG) chains for polyamine largely influence physico-chemical properties of PANs and their biological endpoints. Poly(allylamine hydrochloride) (PAH) are functionalized through carbodiimide chemistry with three ratios of PEG molecules per PAH chain: 0.1, 1, and 10. PEGylated PAH is then assembled into PANs by exposing the polymer to phosphate buffer solution. PANs decrease size and surface charge with increasing PEG ratios as evidenced by dynamic light scattering and zeta potential measurements, with the ten PEG/PAH ratio PANs having practically zero charge. Small angle X-ray scattering (SAXS) proves that PEG chains form a shell around a polyamine core, which is responsible for the screening of positive charges. MTT experiments show that the screening of amine groups decreases nanoparticle toxicity, with the lowest toxicity for the 10 PEG/PAH ratio. Fluorescence correlation spectroscopy (FCS) proves less interaction with proteins for PEGylated PANs. Positron emission tomography (PET) imaging of 18 F labelled PANs shows longer circulation time in healthy mice for PEGylated PANs than non-PEGylated ones.
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Nanopartículas , Fosfatos , Animais , Camundongos , Nanopartículas/toxicidade , Poliaminas/toxicidade , Polietilenoglicóis , Espalhamento a Baixo Ângulo , Difração de Raios XRESUMO
The interaction of polyamine poly(allylamine hydrochloride) with Na3PO4, Na4P2O7, Na5P3O10, Na6P6O18, and (NaPO3)26 salts and the formation of polyamine phosphate nanoparticles (PANs) are studied here. Dynamic light scattering, isothermal titration calorimetry (ITC), electrophoretical mobility measurements, atomic force microscopy, and transmission electron microscopy are used to explore the formation, stability, and pH sensitivity of PANs. An optimal concentration for PAN formation is found for each phosphate salt in terms of the most stable size and lowest polydispersity index of the nanoparticles. The minimal concentration of phosphate ions for PAN formation decreases with the increasing number of phosphate groups per phosphate salt. ITC measurements show that all polyphosphates display a characteristic endothermic peak, which is not present when monophosphates are used for PAN formation. pH stability of PANs depends on the type of phosphate salt. PANs formed with small phosphates show a small window of stability with pH from 8 to 9, while those formed with long phosphates are stable in more acidic pH environments. Our findings open multiple possibilities for fine-tuning the pH sensitivity of PANs by varying phosphate salts for potential applications in drug delivery.
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Polymer brushes have a large potential for controlling properties such as surface lubrication or wetting through facile functionalization. Polymer chemistry, chain density, and length impact on the wetting properties of brushes. This study explores the use of diblock copolymer brushes with different block length and spatial arrangement of the blocks to tune surface wettability. Block copolymer brushes of the polyelectrolyte [2-(methacryloyloxy)ethyl] trimethylammonium chloride (PMETAC) with a contact angle of 17° and a hydrophobic block of (1)H, (1)H, (2)H, (2)H-perfluorodecyl Acrylate (PPFDA) with a contact angle of 130° are synthesized by RAFT polymerization. By changing the sequence of polymerization either block is synthesized as top or bottom block. By varying the concentration of initiator the length of the blocks is varied. Contact angle values with intermediate values between 17° and 130° are measured. In addition, by changing solvent pH and in presence of a different salt the contact angle of the copolymer brushes can be fine tuned. Brushes are characterized by atomic force microscopy, Raman confocal microscopy, and X-ray photoelectron spectroscopy.
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Polímeros/química , Concentração de Íons de Hidrogênio , Microscopia de Força Atômica , Microscopia Confocal , Espectroscopia Fotoeletrônica , Polimerização , Polímeros/síntese química , Solventes/química , Propriedades de Superfície , Temperatura , Água/química , MolhabilidadeRESUMO
Selective enhancement of directional migration of endotheliocytes (ECs) over vascular smooth muscle cells (SMCs) plays a significant role for the fast endothelialization of blood-contacting implants, in particular for the antirestenosis of vascular stents. Herein, a complementary density gradient of poly(2-hydroxyethyl methacrylate) (PHEMA) brushes and YIGSR peptide, a sequence specifically improving the mobility of ECs, was fabricated using a dynamically controlled reaction process. The gradients were visualized by fluorescent labeling and further quantified by X-ray photoelectron spectrometry (XPS) and quartz crystal microbalance with dissipation (QCM-d). The ECs exhibited preferential orientation and enhanced directional migration behavior on the gradient surface toward the region of lower PHEMA density and higher YIGSR density. The migration rate of the ECs was significantly enhanced to 5-fold, whereas the mobility of SMCs was not significantly influenced, leading to faster migration of ECs than SMCs. Therefore, the success of the complementary gradient relies on the appropriate interplay between the PHEMA brushes and the cell-specific ligands, enabling the selective guidance of EC migration.
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Movimento Celular/fisiologia , Células Endoteliais/metabolismo , Oligopeptídeos/química , Oligopeptídeos/metabolismo , Poli-Hidroxietil Metacrilato/química , Poli-Hidroxietil Metacrilato/metabolismo , Células Cultivadas , Centrifugação com Gradiente de Concentração/métodos , Humanos , Especificidade por Substrato/fisiologiaRESUMO
Fabrication of batch-wise efficient, user- and environmentally-friendly, and well-defined yield methods for the synthesis of graphite oxide, the main precursor to graphene oxide and its reduced derivative, is an essential and robust research field, yet is sparingly investigated or innovated in recent years. This Concept review showcases recent advances in the fabrication of electrochemical set ups that meet aforementioned design parameters, wherein working electrode construction is seen to play a key role in shaping the yield characteristics and aiding the mechanistic understanding of efficiency of adopted methods. Particularly, these advances pave the way for new and various tunable design parameters by fabricating different methods of encapsulating graphite powder instead of using conventional bare monolith forms of graphite as working electrode. Encapsulation geometry, pressure, and matrix material, as well as powder size are examples of such tunable design parameters, absent in the monolith methods. The encapsulation validates authenticity of real-time monitoring of electrochemical intercalation, exfoliation, and oxidation of graphite powder, thereby offering excellent and well-defined control on yield.
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The present study focuses on the elaboration of magnetic nanocomposites by the in situ incorporation of magnetite (Fe3O4) nanoparticles (NPs) with spherical and nanoflower-like morphologies in graphitic carbon nitride (g-C3N4) sheets using two different synthetic routes. Nanomaterials are characterized by TEM, SEM, XRD, FTIR, BET, zetametry, vibrating sample magnetometry, and UV-vis absorption spectroscopy. The decoration of the carbon nitride matrix with the magnetic NPs enhanced optical and textural properties. The influence of the morphology of the magnetic NPs on the adsorptive and photocatalytic properties of the nanocomposites under different pH conditions (4.5, 6.9, and 10.6) was assessed from batch tests to remove methylene blue (MB) from aqueous solutions. In extreme pH conditions, the nanocomposites exhibited lower or equivalent MB removal capacity compared to the pure g-C3N4. However, at neutral medium, the nanocomposite with incorporated Fe3O4 nanoflowers showed a significantly higher removal efficiency (80.7%) due to the combination of a high adsorption capacity and a good photocatalytic activity in this pH region. The proposed nanocomposite is a promising alternative to remove cationic dyes from water by magnetic assistance, since no pH adjustment of the polluted effluent is required, reducing costs and environmental impact in the dyeing industry.
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This study presents an optimized microwave-assisted method for the green synthesis of silver nanoparticles (AgNPs) using a root extract obtained from Pelargonium sidoides DC. The influence of temperature, reagent concentration, and irradiation time was systematically investigated to enhance synthesis yield. Characterization techniques including XRD, UV-vis, FTIR, XPS, and zetametry were employed to confirm the successful formation of nanoparticles with a metallic silver core (â¼17 nm) functionalized with organic molecules derived from the plant extract. The cytotoxicity of AgNPs was assessed using a cell viability assay, while the Minimum Inhibitory Concentration (MIC) of nanoformulation against pathogenic bacteria, including Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and the carbapenem-resistant Klebsiella pneumoniae (KPC), was determined using the Broth microdilution method. The nanoformulation synthesized with P. sidoides extract exhibited a dose-dependent response, demonstrating superior antimicrobial efficacy compared to the pure plant extract in most cases. The MIC values ranged from 0.85 to 17.1 µg mL-1, with particularly strong performance against the drug resistant KPC strain. The enhanced antimicrobial effect is attributed to the synergistic action of the metallic silver core and phytochemicals from P. sidoides on the surface of nanoparticles, which also contribute to notable colloidal stability of AgNPs at physiological pH levels.
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Porous transition metal oxides are widely studied as biocompatible materials for the development of prosthetic implants. Resurfacing the oxide to improve the antibacterial properties of the material is still an open issue, as infections remain a major cause of implant failure. We investigated the functionalization of porous titanium oxide obtained by anodic oxidation with amino acids (Leucine) as a first step to couple antimicrobial peptides to the oxide surface. We adopted a two-step molecular deposition process as follows: self-assembly of aminophosphonates to titanium oxide followed by covalent coupling of Fmoc-Leucine to aminophosphonates. Molecular deposition was investigated step-by-step by Atomic Force Microscopy (AFM) and X-ray Photoemission Spectroscopy (XPS). Since the inherent high roughness of porous titanium hampers the analysis of molecular orientation on the surface, we resorted to parallel experiments on flat titanium oxide thin films. AFM nanoshaving experiments on aminophosphonates deposited on flat TiO2 indicate the formation of an aminophosphonate monolayer while angle-resolved XPS analysis gives evidence of the formation of an oriented monolayer exposing the amine groups. The availability of the amine groups at the outer interface of the monolayer was confirmed on both flat and porous substrates by the following successful coupling with Fmoc-Leucine, as indicated by high-resolution XPS analysis.
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This feature article deals with the self assembly and physical chemistry of polyelectrolytes: multilayers and brushes. The article highlights the interesting behavior of polyelectrolytes in nanoscale assemblies, giving more insight into the complexity of the formation of the assemblies. The water content of multilayers and brushes is studied during the assembly and in different ionic strengths. Similarities are found in the behavior of the brushes and multilayers with ionic strength, with regard to changes in the thickness and the water content. An invariance of the zeta potential with ionic strength is also observed for both systems, which can be explained as a result of conformational changes of the polymer chains. Finally, the combination of brushes and multilayers for surface modification is presented.
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Nanopartículas/química , Polímeros/química , Água/química , Concentração Osmolar , Propriedades de SuperfícieRESUMO
The main goal of this study is to evaluate the efficacy of the paclitaxel (PTX) drug formulated with a liposomal nanosystem (L-PTX) in a peritoneal carcinomatosis derived from ovarian cancer. In vitro cell viability studies with the human ovarian cancer line A2780 showed a 50% decrease in the inhibitory concentration for L-PTX compared to free PTX. A2780 cells treated with the L-PTX formulation demonstrated a reduced capacity to form colonies in comparison to those treated with PTX. Cell death following L-PTX administration hinted at apoptosis, with most cells undergoing initial apoptosis. A2780 cells exhibited an inhibitory migration profile when analyzed by Wound Healing and real-time cell analysis (xCELLigence) methods after L-PTX administration. This inhibition was related to decreased expression of the zinc finger E-box-binding homeobox 1 (ZEB1) and transforming growth factor 2 (TGF-ß2) genes. In vivoL-PTX administration strongly inhibited tumor cell proliferation in ovarian peritoneal carcinomatosis derived from ovarian cancer, indicating higher antitumor activity than PTX. L-PTX formulation did not show toxicity in the mice model. This study demonstrated that liposomal paclitaxel formulations are less toxic to normal tissues than free paclitaxel and are more effective in inhibiting tumor cell proliferation/migration and inducing ZEB1/TGF-ß2 gene expression.
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Antineoplásicos Fitogênicos/farmacologia , Carcinoma Epitelial do Ovário/tratamento farmacológico , Neoplasias Ovarianas/tratamento farmacológico , Paclitaxel/farmacologia , Animais , Antineoplásicos Fitogênicos/administração & dosagem , Apoptose/efeitos dos fármacos , Carcinoma Epitelial do Ovário/genética , Carcinoma Epitelial do Ovário/patologia , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Lipossomos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/patologia , Paclitaxel/administração & dosagem , Neoplasias Peritoneais/tratamento farmacológicoRESUMO
The widespread occurrence of nosocomial infections and the emergence of new bacterial strands calls for the development of antibacterial coatings with localized antibacterial action that are capable of facing the challenges posed by increasing bacterial resistance to antibiotics. The Layer-by-Layer (LbL) technique, based on the alternating assembly of oppositely charged polyelectrolytes, can be applied for the non-covalent modification of multiple substrates, including medical implants. Polyelectrolyte multilayers fabricated by the LbL technique have been extensively researched for the development of antibacterial coatings as they can be loaded with antibiotics, antibacterial peptides, nanoparticles with bactericide action, in addition to being capable of restricting adhesion of bacteria to surfaces. In this review, the different approaches that apply LbL for antibacterial coatings, emphasizing those that can be applied for implant modification are presented.
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The increasing amount of organic dye-polluted wastewater from the textile industry makes the development of techniques for the efficient purification and reuse of wastewater an urgent issue. Accordingly, solid adsorbents based on three-dimensional (3D) reduced graphene oxide (rGO) aerogels combined with magnetic nanoparticles (rGO@Fe3O4) appear to be potential materials, which offer fast and efficient discoloration of dye solutions by dye adsorption, simultaneously acting as Fenton reaction nanocatalysts, and thus may eliminate organic dyes. In this work, 3D rGO@Fe3O4 aerogel nanocatalysts were synthesized via a low-energy, simple, one-step in situ method, in which GO and FeSO4·7H2O were simultaneously reduced. Consequently, monolithic porous nanocatalyst 3D structures were obtained, with a specific surface area of 241 m2 g-1 and pore volume 0.39 cm3 g-1. The nanocatalysts were applied for the degradation of Acid Red 1 azo-dye in aqueous solution in the presence of hydrogen peroxide, without the need for external energy. The effect of the adsorbent dose, and concentration of dye and peroxide on the dye removal was studied. The degradation of the dye was monitored by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. It was found that an increase in the amount of peroxide allowed complete degradation of the dye together with high molar mass side-products with a conjugated aromatic structure. The good nanocatalyst performance was explained based on the charge-transfer complex established between rGO and the magnetic nanoparticles, allowing the regeneration of ferrous ions during the Fenton process.
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HYPOTHESIS: Doxorubicin hydrochloride (DX) is widely used as a chemotherapeutic agent, though its severe side-effects limit its clinical use. A way to overcome these limitations is to increase DX latency through encapsulation in suitable carriers. However, DX has a high solubility in water, hindering encapsulation. The formulation of DX with sodium cholate (NaC) will reduce aqueous solubility through charge neutralization and hydrophobic interactions thus facilitating DX encapsulation into poloxamer (F127) micelles, increasing drug latency. EXPERIMENTS: DX/NaC/PEO-PPO-PEO triblock copolymer (F127) formulations with high DX content (DX-PMs) have been prepared and characterized by scattering techniques, transmission electron microscopy and fluorescence spectroscopy. Cell proliferation has been evaluated after DX-PMs uptake in three cell lines (A549, Hela, 4T1). Cell uptake of DX has been studied by means of confocal laser scanning microscopy and flow cytometry. FINDINGS: DX-PMs formulations result in small and stable pluronic micelles, with the drug located in the apolar core of the polymeric micelles. Cell proliferation assays show a delayed cell toxicity for the encapsulated DX compared with the free drug. Data show a good correlation between cytotoxic response and slow DX delivery to nuclei. DX-PMs offer the means to restrict DX delivery to the cell interior in a highly stable and biocompatible formulation, suitable for cancer therapy.
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Micelas , Poloxâmero , Disponibilidade Biológica , Doxorrubicina/farmacologia , Polietilenoglicóis , Colato de SódioRESUMO
This study aimed to evaluate the effects of an intratesticular injection of silver nanoparticles (AgNPs) on reproductive parameters and health of rats, and to evaluate the AgNPs biodistribution in order to develop a nanotechnological contraceptive agent for male animals. Treated animals received 220 µL of AgNPs solution (0.46 µg-Ag/ml) in each testicle and were euthanized: seven, 14, 28, and 56 days after injection. A significant decrease (p < 0.05) in the percentage of motile sperm in D7 (8.8%) was observed, comparing to the control (73.3%), D14 (86.0%), D28 (68.2%), and D56 (90.0%) groups. D7 group also presented a decrease (p < 0.05) in the percentage of normal spermatozoa. Additionally, D7 group showed an increase (p < 0.05) in abnormal midpiece and sperm head morphology compared to the Control group. Seminiferous tubules presented all germline cell types and spermatozoa for all groups. However, D7 group did not present spermatozoa in the epididymis, whereas some spermatozoa and cellular debris were visible in D14 and D28 groups. All animals presented hematological parameters, creatinine, and alanine aminotransferase values within the normal limits for Wistar rats. The percentage of silver found in the liver was always higher than in the other organs analyzed. A pioneering mathematical model is proposed, from which the half-life time of silver in the liver (17 days), spleen (23 days), lungs (30 days), and kidneys (35 days) was extracted. In conclusion, some acute and severe toxic effects were observed in sperm cells following intratesticular injection of AgNPs, although these effects were reversible. No adverse effects to general animal health were observed.
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Nanopartículas Metálicas/toxicidade , Reprodução/efeitos dos fármacos , Prata/toxicidade , Espermatozoides/efeitos dos fármacos , Testículo/efeitos dos fármacos , Alanina Transaminase/metabolismo , Animais , Epididimo/efeitos dos fármacos , Epididimo/metabolismo , Rim/efeitos dos fármacos , Rim/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Nanopartículas Metálicas/administração & dosagem , Ratos , Ratos Wistar , Prata/administração & dosagem , Prata/farmacocinética , Espermatozoides/metabolismo , Baço/efeitos dos fármacos , Baço/metabolismo , Testículo/metabolismo , Distribuição TecidualRESUMO
Aim: To investigate the effect of liposomes containing the classical cytotoxic drugs paclitaxel and doxorubicin (Lipo-Pacli/Dox), against a metastatic breast cancer model. We also investigated if Lipo-Pacli/Dox was capable of reverting the tolerogenic environment of metastatic lesions. Materials & methods: Immunogenic cell death induction by the Pacli/Dox combination was assessed in vitro. Antitumor activity and in vivo safety of Lipo-Pacli/Dox were evaluated using a 4T1 breast cancer mouse model Results: Lipo-Pacli/Dox, with a size of 189 nm and zeta potential of -5.01 mV, promoted immune system activation and partially controlled the progression of pulmonary metastasis. Conclusion: Lipo-Pacli/Dox was useful to control both primary tumor and lung metastasis in breast cancer (4T1) mice model. Additionally, Lipo-Pacli/Dox acts as an immunological modulator for this metastatic breast cancer model.
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Lipossomos , Neoplasias Pulmonares , Animais , Antibióticos Antineoplásicos , Linhagem Celular Tumoral , Doxorrubicina , Neoplasias Pulmonares/tratamento farmacológico , Linfócitos , Camundongos , Camundongos Endogâmicos BALB C , Paclitaxel , PrognósticoRESUMO
The quartz crystal microbalance with dissipation technique (QCM-D) and atomic force microscopy (AFM) have been employed to study the interaction of N-tetradecyl trimethyl ammonium bromide (TdTmAB) with polyelectrolyte multilayers containing poly(sodium 4-styrene sulfonate) (PSS) as the polyanion and either poly(allylamine hydrochloride) (PAH) or poly(diallyl dimethyl ammonium chloride) (PDADMAC) as the polycations. The multilayers were exposed to aqueous solutions of TdTmAB. This resulted in a selective removal of PDADMAC PSS layers while layers with PAH as polycation remained stable. It is suggested that PDADMAC/PSS multilayers can be employed as strippable protecting layers.
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The diffusion of sodium dithionite (S2O42-) through polyelectrolyte multilayers of poly(diallyl dimethyl ammonium chloride) (PDADMAC)/poly(styrene sodium sulfonate) (PSS) assembled on colloidal particles with the layer-by-layer technique is studied by means of flow cytometry and quenching assay. Fluorescence is provided by a layer of (7-nitrobenz-2-oxa-1,3-diazol-4yl) amino) hexanoate (NBD)-labeled poly(allyl amine hydrochloride) assembled below the PDADMAC/PSS multilayer. NBD is quenched by a redox reaction with S2O42-. NBD quenching is fast at short times but strongly retarded at longer times. Quenching is faster for PDADMAC as the top layer and for increasing concentrations of S2O42-. The quenching kinetics of NBD is described with a model assuming a non-Fickean diffusion of S2O42-, with diffusion coefficients that depend on time with an inverse power law. Diffusion coefficients show little dependence on the number of layers but are highly dependent on the concentration of S2O42-. Increasing the concentration of S2O42- over 10 mol/m3 results in a decrease of the diffusion coefficient, more evident at longer times. The non-Fickean behavior for S2O42- diffusion is explained on the basis of the trapping of dithionites in the multilayers.
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Remotely assisted drug delivery by means of magnetic biopolymeric nanoplatforms has been utilized as an important tool to improve the delivery/release of hydrophobic drugs and to address their low cargo capacity. In this work, MnFe2O4 magnetic nanoparticles (MNPs) were synthesized by thermal decomposition, coated with citrate and then functionalized with the layer-by-layer (LbL) assembly of polyelectrolyte multilayers, with chitosan as polycation and sodium alginate as polyanion. Simultaneous conductimetric and potentiometric titrations were employed to optimize the LbL deposition and to enhance the loading capacity of nanoplatforms for curcumin, a hydrophobic drug used in cancer treatment. ~200â¯nm sized biopolymer platforms with ~12â¯nm homogeneously embedded MNPs were obtained and characterized by means of XRD, HRTEM, DLS, TGA, FTIR, XPS and fluorescence spectroscopy techniques to access structural, morphological and surface properties, to probe biopolymer functionalization and to quantify drug-loading. Charge reversals (±30â¯mV) after each deposition confirmed polyelectrolyte adsorption and a stable LbL assembly. Magnetic interparticle interaction was reduced in the biopolymeric structure, hinting at an optimized performance in magnetic hyperthermia for magneto-assisted drug release applications. Curcumin was encapsulated, resulting in an enhanced payload (~100⯵g/mg). Nanocytotoxicity assays showed that the biopolymer capping enhanced the biocompatibility of nanoplatforms, maintaining entrapped curcumin. Our results indicate the potential of synthesized nanoplatforms as an alternative way of remotely delivering/releasing curcumin for medical purposes, upon application of an alternating magnetic field, demonstrating improved efficiency and reduced toxicity.
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Alginatos/química , Quitosana/química , Curcumina/química , Compostos Férricos/química , Nanopartículas de Magnetita/química , Compostos de Manganês/química , Materiais Biocompatíveis/química , Sobrevivência Celular/efeitos dos fármacos , Curcumina/metabolismo , Curcumina/farmacologia , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Humanos , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Células MCF-7 , Tamanho da PartículaRESUMO
The impact of polyanions on the formation of lipid bilayers on top of polyelectrolyte multilayers (PEMs) with poly(allylamine hydrochloride) (PAH) as the top layer is studied for the deposition of vesicles of mixed lipid composition, 50:50 molar ratio of zwitterionic 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and negatively charged 1,2-dioleoyl-sn-glycero-3-phospho-l-serine (DOPS). PEMs are assembled with polystyrene sulfonate (PSS), poly(acrylic acid) (PAA), and alginic acid sodium salt (Alg) as polyanions. The assembly of the vesicles on the PEMs is followed by means of the quartz crystal microbalance with dissipation. Fluorescence recovery after photobleaching measurements are applied to evaluate bilayer formation. Whereas a bilayer is formed on top of PAH/PSS multilayers, the vesicles are adsorbed on top of PAH/Alg and PAH/PAA multilayers, remaining unruptured or only partially fused. The influence of the surface composition of the PEM and of the bulk properties of the film are analyzed. The phosphate ions present in phosphate-buffered saline (PBS) play a fundamental role in bilayer formation on top of PAH/PSS as they complex with PAH and render the surface potential close to zero. For PAH/PAA and PAH/Alg, PBS renders the surface negative. X-ray photoelectron spectroscopy shows that the dibasic phosphate ions from PBS complex preferentially with PAH in PAH/PAA and PAH/Alg multilayers, whereas monobasic phosphates complex with PAH in PAH/PSS. An explanation for the absence of bilayer formation on PAH/PAA and PAH/Alg is given on the basis of the different affinities of phosphate ions for PAH in combination with the different polyanions.