Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.027
Filtrar
1.
Phys Chem Chem Phys ; 22(8): 4574-4580, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32048659

RESUMO

The organization of multiple subcellular compartments is controlled by liquid-liquid phase separation. Phase separation of this type occurs with the emergence of interfacial tension. Aqueous two-phase systems formed by two non-ionic polymers can be used to separate and analyze biological macromolecules, cells and viruses. Phase separation in these systems may serve as the simple model of phase separation in cells also occurring in aqueous media. To better understand liquid-liquid phase separation mechanisms, interfacial tension was measured in aqueous two-phase systems formed by dextran and polyethylene glycol and by polyethylene glycol and sodium sulfate in the presence of different additives. Interfacial tension values depend on differences between the solvent properties of the coexisting phases, estimated experimentally by parameters representing dipole-dipole, ion-dipole, ion-ion, and hydrogen bonding interactions. Based on both current and literature data, we propose a mechanism for phase separation in aqueous two-phase systems. This mechanism is based on the fundamental role of intermolecular forces. Although it remains to be confirmed, it is possible that these may underlie all liquid-liquid phase separation processes in biology.


Assuntos
Biotecnologia/métodos , Extração Líquido-Líquido , Água/química , Separação Celular , Dextranos/química , Complexos Multiproteicos/química , Complexos Multiproteicos/isolamento & purificação , Polietilenoglicóis/química , Sulfatos/química , Tensão Superficial , Vírus/isolamento & purificação
2.
Biosens Bioelectron ; 151: 111970, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31868609

RESUMO

Herein, a credible construction strategy to improve electrochemiluminescence (ECL) of luminol was developed based on Cu2O-Au heterostructures. Summarily, gold nanoparticles (AuNPs) were anchored on surface of Cu2O nanocube (Cu2O@AuNPs) by spontaneous reduction reaction. Then, luminol molecules were concentrated on Cu2O@AuNPs using L-Cysteine (Cys) as covalent linkage to build the composite emitter (Cu2O@AuNPs-Cys-luminol). The enhancement mechanism was realized by following aspects: (I) Cu2O@AuNPs worked as electrocatalyst for glucose to generate coreactant of H2O2 in situ, avoiding the instability of direct addition of H2O2. (II) luminol molecules were firmly attached on Cu2O@AuNPs to achieve centralized and strong luminescence at low consumption. (III) Cys acted as an intramolecular coreactant and directly linked to luminol to increase luminous efficiency. To validate the effectiveness, a sandwiched immunoassay was built using concanavalinA (ConA) as analyte. Electroreduced graphene film as substrate provided phenoxy-derivatized dextran (DexP) with abundant binding sites and improved conductivity. To improve the specificity, DexP was used to identify ConA via the specific carbohydrate-ConA interaction. Then, Cu2O@AuNPs-Cys-luminol was modified on electrode as ECL signal indicator. The ECL immunosensor achieved determination of ConA with low detection limit of 2.9 × 10-5 ng/mL and excellent stability of continuous potential scan for 8 cycles. Experimental results demonstrated that the proposed construction strategy made considerable progress in ECL efficiency and stability of luminol. The creational pattern of construction strategy achieves high detection capabilities to ConA and expands the applicability of luminol in ECL system. It is expected to have more potential application value in immunoassay with universality.


Assuntos
Cobre/química , Ouro/química , Luminol/química , Nanopartículas Metálicas/química , Técnicas Biossensoriais , Concanavalina A/análise , Cisteína/química , Dextranos/química , Técnicas Eletroquímicas , Eletrodos , Peróxido de Hidrogênio/química , Limite de Detecção , Medições Luminescentes , Oxirredução , Sensibilidade e Especificidade , Propriedades de Superfície
3.
Pharm Res ; 37(1): 14, 2019 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-31873808

RESUMO

PURPOSE: The aim of this study is to determine the effects of saccharide-containing excipients on the surface composition of spray-dried protein formulations and their matrix heterogeneity. METHODS: Spray-dried formulations of myoglobin or bovine serum albumin (BSA) were prepared without excipient or with sucrose, trehalose, or dextrans. Samples were characterized by solid-state Fourier-transform infrared spectroscopy (ssFTIR), differential scanning calorimetry (DSC), size exclusion chromatography (SEC) and scanning electron microscopy (SEM). Protein surface coverage was determined by X-ray photoelectron spectroscopy (XPS), while conformational differences were determined by solid-state hydrogen/deuterium exchange with mass spectrometry (ssHDX-MS). RESULTS: Structural differences were exhibited with the inclusion of different excipients, with dextran formulations indicating perturbation of secondary structure. XPS indicated sucrose and trehalose reduced protein surface concentration better than dextran-containing formulations. Using ssHDX-MS, the amount of deuterium incorporation and populations present were the largest in the samples processed with dextrans. Linear correlation was found between protein surface coverage and ssHDX-MS peak area (R2 = 0.853) for all formulations with saccharide-containing excipients. CONCLUSIONS: Lower molecular weight species of saccharides tend to enrich the particle surface and reduce protein concentration at the air-liquid interface, resulting in reduced population heterogeneity and improved physical stability, as identified by ssHDX-MS.


Assuntos
Excipientes/química , Mioglobina/química , Soroalbumina Bovina/química , Química Farmacêutica/métodos , Dessecação/métodos , Deutério/química , Dextranos/química , Espectrometria de Massas/métodos , Sacarose/química , Propriedades de Superfície , Trealose/química
4.
Chem Commun (Camb) ; 55(92): 13880-13883, 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31675031

RESUMO

Based on the unique property of preferential sequestration of guest molecules, coacervate microdroplets are proposed as enzyme active membrane-free protocells, in which uricase is loaded for efficient detoxification of uric acid in serum.


Assuntos
Urato Oxidase/metabolismo , Ácido Úrico/metabolismo , Células Artificiais/química , Dextranos/química , Corantes Fluorescentes/química , Humanos , Polietilenos/química , Estabilidade Proteica , Compostos de Amônio Quaternário/química , Solubilidade , Ácido Úrico/sangue
5.
J Agric Food Chem ; 67(47): 13108-13118, 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31738546

RESUMO

Glucansucrases can be used to glucosylate various plant-derived phenolic compounds by using sucrose as donor substrate. We applied Lactobacillus reuteri TMW 1.106 dextransucrase to glucosylate the acceptor substrates caffeic acid and gallic acid. Subsequently, monoglucosylated and in particular oligo- and polyglucosylated conjugates were characterized by using different chromatographic techniques and two-dimensional NMR spectroscopy. Both acceptors were substituted at positions O3 and O4. Under the conditions used, two monoglucosylated products were formed for caffeic acid, whereas only one O3-monosubstituted conjugate was detected for gallic acid. However, both acceptors resulted in O4-substituted oligo- and polyglucosylated conjugates, the amount of which was higher from gallic acid than from caffeic acid. Profile analysis tensiometry suggested that, in contrast to unmodified dextrans, oligo- and polymeric glucoconjugates of gallic acid are highly interfacially active. Overall, we provide the first detailed characterization of enzymatically conjugated oligo- and polymeric dextrans, which may have further potential as functional ingredients.


Assuntos
Proteínas de Bactérias/química , Ácidos Cafeicos/química , Ácido Gálico/química , Glucose/química , Glucosiltransferases/química , Lactobacillus reuteri/enzimologia , Biocatálise , Dextranos/química , Glicosilação
6.
Int J Nanomedicine ; 14: 8421-8432, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31749616

RESUMO

Purpose: Immune activation with T cell tumor infiltration is beneficial for the prognosis of patients suffering from solid cancer. Depending on their immune status, solid tumors can be immunologically classified into three groups: "hot" tumors are infiltrated with T lymphocytes, "cold" tumors are not infiltrated and "immune excluded" tumors are only infiltrated in the peripheral tumor tissue. Checkpoint inhibitors provide new therapeutic options for "hot" tumors by triggering the immune response of T cells. In order to enable this for cold tumors as well, T cells must be enriched in the tumor. Therefore, we use the principle of magnetic targeting to guide T cells loaded with citrate-coated superparamagnetic iron oxide nanoparticles (SPIONCitrate) to the tumor by an externally applied magnetic field. Methods: SPIONCitrate were produced by alkaline coprecipitation of iron(II) and iron(III) chloride and in situ coating with sodium citrate. The concentration-dependent cytocompatibility of the particles was determined by flow cytometry and blood stability assays. Atomic emission spectroscopy was used for the quantification of the particle uptake into T lymphocytes. The attractability of the loaded cells was observed by live-cell imaging in the presence of an externally applied magnetic field. Results: SPIONCitrate displayed good cytocompatibility to T cells and did not show any sign of aggregation in blood. Finally, SPIONCitrate-loaded T cells were strongly attracted by a small external magnet. Conclusion: T cells can be "magnetized" by incorporation of SPIONCitrate for magnetic targeting. The production of the particle-cell hybrid system is straightforward, as the loading process only requires basic laboratory devices and the loading efficiency is sufficient for cells being magnetically controllable. For these reasons, SPIONCitrate are potential suitable candidates for magnetic T cell targeting.


Assuntos
Ácido Cítrico/química , Dextranos/química , Imunoterapia , Magnetismo , Nanopartículas de Magnetita/química , Neoplasias/imunologia , Neoplasias/terapia , Linfócitos T/metabolismo , Linhagem Celular Tumoral , Dextranos/sangue , Dextranos/toxicidade , Dextranos/ultraestrutura , Humanos , Ferro/metabolismo , Nanopartículas de Magnetita/toxicidade , Nanopartículas de Magnetita/ultraestrutura , Neoplasias/sangue , Espécies Reativas de Oxigênio/metabolismo
7.
Int J Nanomedicine ; 14: 6813-6830, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31692568

RESUMO

Background: We recently showed that quercetin-conjugated iron oxide nanoparticles (QNPs) promoted the bioavailability of quercetin (Qu) in the brain of rats and improved the learning and memory of diabetic rats. In this study, we characterized the modifications in the antitoxic effects of Qu after conjugation. Materials and methods: We conjugated Qu to dextran-coated iron oxide nanoparticles (DNPs) and characterized DNPs and QNPs using FTIR, XRD, DLS, Fe-SEM, and EDX analyzes. The antiradical properties of Qu, DNPs, and QNPs were compared by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity assay. Catalase-like activities of DNPs and QNPs were estimated using catalase activity assay kit, and the antitoxic effects of Qu and QNPs were evaluated with spectrophotometry, MTT assay, flow cytometry, and real-time q-PCR. Results: Qu had a stronger anti-radical activity than DNPs and its activity decreased after being conjugated to DNPs. The catalase-like activity of DNPs remained intact after conjugation. DNPs had less toxicity on PC12 cells viabilities as compared to free Qu, and the conjugation of Qu with DNPs attenuated its cytotoxicity. Furthermore, MTT assay results indicated 24 h pretreatment with Qu had more protective effects than QNPs against H2O2-induced cytotoxicity, while Qu and QNPs had the same effects for 48 and 72 h incubation. Although the total antioxidant capacity of Qu was attenuated after conjugation, the results of flow cytometry and real-time q-PCR confirmed that 24 h pretreatment with the low concentrations of Qu and QNPs had the similar antioxidant, anti-inflammatory, and anti-apoptotic effects against the cytotoxicity of H2O2. Conclusion: Qu and QNPs showed the similar protective activities against H2O2-induced toxicity in PC12 cells. Given the fact that QNPs have magnetic properties, they may serve as suitable carriers to be used in neural research and treatment.


Assuntos
Antioxidantes/farmacologia , Compostos Férricos/química , Peróxido de Hidrogênio/toxicidade , Nanopartículas Metálicas/uso terapêutico , Quercetina/farmacologia , Animais , Antioxidantes/química , Antioxidantes/farmacocinética , Catalase/farmacologia , Dextranos/química , Liberação Controlada de Fármacos , Compostos Férricos/farmacologia , Depuradores de Radicais Livres/química , Depuradores de Radicais Livres/farmacologia , Nanopartículas Metálicas/química , Células PC12 , Quercetina/química , Quercetina/farmacocinética , Ratos , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
8.
Carbohydr Polym ; 226: 115308, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31582057

RESUMO

The paper focuses on the development of drug delivery systems based on hydrogels of dextran phosphate (DP) for local cancer therapy. The hydrogels were characterized by physicochemical properties including functional group content, morphology, gel fraction, pH-responsive swelling. The desirable pH-sensitive drug release behavior of these hydrogels was demonstrated by a drug release test with Prospidine-loaded hydrogels (DP-Pr hydrogels) at different pH values. In vitro degradation of the DP-Pr hydrogels was determined under simulated physiological conditions. The cytotoxicity of the blank DP hydrogels and DP-Pr hydrogels with different Pr concentrations was evaluated with HeLa and HЕр-2 cells. Investigations of antitumor efficiency in vivo showed that administration of DP-Pr hydrogels in comparison with an aqueous solution of Pr results in the increase of antitumor activity, prolongation of therapeutic action and growth of a number of animals cured. Therefore, such pH-responsive DP hydrogels could be promising candidates as drug delivery carriers.


Assuntos
Antineoplásicos/administração & dosagem , Dextranos/química , Portadores de Fármacos/química , Hidrogéis/química , Prospídio/administração & dosagem , Animais , Liberação Controlada de Fármacos , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Ratos
9.
J Agric Food Chem ; 67(46): 12806-12815, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31650841

RESUMO

Lactic acid bacteria are known to produce extracellular polysaccharides such as α-glucan, levan, and inulin, which are promising for applications in food systems because of their prebiotic properties. In this work, a novel glucansucrase (GS) Gtf-DSM from Lactobacillus ingluviei DSM 14792 was recombinantly expressed and biochemically characterized as a dextransucrase capable of producing a dextran polysaccharide with four types of linkages, including 69% (α1 → 6), 24% (α1 → 3), 6% (α1 → 4), and 1% (α1 → 2). Intriguingly, the dextransucrase Gtf-DSM had a sequence identity of 99.3% with the reuteransucrase GtfO producing a reuteran with 21% (α1 → 6) and 79% (α1 → 4) linkages. Thus, the dextransucrase Gtf-DSM is a unique target for understanding the linkage specificity of GSs and the investigation of site-directed mutagenesis using Gtf-DSM and GtfO as templates is underway.


Assuntos
Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Glucosiltransferases/química , Glucosiltransferases/metabolismo , Lactobacillus/enzimologia , Proteínas de Bactérias/genética , Dextranos/química , Dextranos/metabolismo , Glucosiltransferases/genética , Glicosiltransferases/química , Glicosiltransferases/genética , Glicosiltransferases/metabolismo , Lactobacillus/química , Lactobacillus/genética , Lactobacillus/metabolismo , Mutagênese Sítio-Dirigida , Especificidade por Substrato
10.
Adv Mater ; 31(44): e1904032, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31550402

RESUMO

Nanosheets have thicknesses on the order of nanometers and planar dimensions in the micrometer range. Nanomaterials that are capable of converting reversibly between 2D nanosheets and 3D structures in response to specific triggers can enable construction of nanodevices. Supra-molecular lipid nanosheets and their triggered conversions to 3D structures including vesicles and cups are reported. They are produced from lipid vesicles upon addition of amphiphilic peptides and cationic copolymers that act as peptide chaperones. By regulation of the chaperoning activity of the copolymer, 2D to 3D conversions are reversibly triggered, allowing tuning of lipid bilayer structures and functionalities.


Assuntos
Dextranos/química , Bicamadas Lipídicas/química , Nanoestruturas/química , Peptídeos/química , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Conformação Molecular , Propriedades de Superfície
11.
Microb Cell Fact ; 18(1): 153, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31506087

RESUMO

BACKGROUND: Dextransucrases are extracellular enzymes, which catalyze the formation of α-1→6-linked glucose polymers from sucrose. These enzymes are exclusively expressed by lactic acid bacteria, which commonly acidify the extracellular environment due to their physiology. Dextransucrases are thus confronted with steadily changing reaction conditions in regards to the environmental pH, which can further affect the amount of released dextransucrases. In this work, we studied the effect of the environmental pH on the release, the productivity and the product specificity of the dextransucrase expressed by Lactobacillus (L.) hordei TMW 1.1822. Dextransucrases were recovered as crude extracts at pH 3.5-pH 6.5 and then again used to produce dextrans at these pH values. The respectively produced dextran amounts and sizes were determined and the obtained results finally systematically correlated. RESULTS: Maximum dextran amounts were produced at pH 4.0 and pH 4.5, while the productivity of the dextransucrases significantly decreased at pH 3.5 and pH 6.5. The distribution of dextran amounts produced at different pH most likely reflects the pH dependent activity of the dextransucrases released by L. hordei, since different transglycosylation rates were determined at different pH using the same dextransucrase amounts. Moreover, similar hydrolysis activities were detected at all tested conditions despite significant losses of transglycosylation activities indicating initial hydrolysis prior to transglycosylation reactions. The molar masses and rms radii of dextrans increased up to pH 5.5 independently of the stability of the enzyme. The gelling properties of dextrans produced at pH 4.0 and pH 5.5 were different. CONCLUSIONS: The presented methodological approach allows the controlled production of dextrans with varying properties and could be transferred and adapted to other microbes for systematic studies on the release and functionality of native sucrases or other extracellular enzymes.


Assuntos
Dextranos/biossíntese , Dextranos/química , Glucosiltransferases/química , Glucosiltransferases/metabolismo , Lactobacillus/enzimologia , Concentração de Íons de Hidrogênio , Cinética , Especificidade por Substrato
12.
Chem Commun (Camb) ; 55(80): 12052-12055, 2019 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-31535680

RESUMO

In this paper we report the kinetics based detection of single nucleotide variation (SNV) at room temperature by allele specific extension with different concentrations and types of crowding agents. In general, the crowding conditions enhanced the specificity in the detection of SNV.


Assuntos
DNA/genética , Nucleotídeos/genética , Polimorfismo de Nucleotídeo Único , Alelos , Animais , Pareamento Incorreto de Bases , Técnicas Biossensoriais/métodos , Bovinos , Dextranos/química , Transferência Ressonante de Energia de Fluorescência/métodos , Corantes Fluorescentes/química , Cinética , Polietilenoglicóis/química , Soroalbumina Bovina/química , Temperatura Ambiente
13.
J Oleo Sci ; 68(10): 959-965, 2019 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-31511465

RESUMO

Protein hydrolysis on the freeze-thaw stability of emulsions prepared with soy protein - dextran conjugates were investigated. Soy protein isolate-dextran (SPI-D) and soy protein hydrolysates-dextran (SPH-D) conjugates with different degree of hydrolysis (DH) were formed by Maillard reaction. The formation of protein-polysaccharide conjugates between SPI/SPH and dextran molecules was confirmed by SDS-PAGE; this finding was consistent with the degree of glycation and the browning index. The freeze-thaw emulsion stability was investigated. The results confirmed that the SPH3-D (DH at 3%) emulsion with 3% DH of SPI exhibited the lowest creaming index after experiencing 1, 2, and 3 freeze-thaw cycles , with results of 7.69%, 20.74% and 31.30%, respectively. The SPH3-D emulsion had a significantly lower average particle size, which was reduced by 48.28% compared to the SPI-D emulsion. Meanwhile, the SPH3-D solution had low interfacial tension. The confocal laser scanning microscopy analysis indicated that the SPH3-D emulsions were strongly stable against the freeze-thaw treatment and could be used as effective emulsifiers in frozen foods.


Assuntos
Anticoagulantes/química , Dextranos/química , Congelamento , Proteínas de Soja/química , Emulsões , Hidrólise , Estabilidade Proteica , Proteínas de Soja/isolamento & purificação
14.
Int J Pharm ; 570: 118654, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31476378

RESUMO

The use of nanoparticles for pulmonary delivery poses challenges such as the presence of anatomical barriers and the loss of bioactive components. Excipients are often used to facilitate delivery. Excipients suitable for nanoparticle delivery are still being explored. Herein we introduce for the first time, spray-dried glycine microparticle-based excipients loaded with nanoparticles of the size range known to be taken up by alveolar macrophages. Using a microfluidic jet spray dryer, we produced glycine microparticles-based excipients which are spherical, uniform, cenospheric (hollow at core), and "coral-like" with average diameter of 60 ±â€¯10 µm, 29 ±â€¯0.8% porosity, and showed their effective loading with glycine coated iron oxide superparamagnetic nanoparticles (GSPIONs). Our loading protocol with nanoparticles further increased microsphere porosity and improved aerodynamic performance unlike the dense, solid commercial excipient, Lactohale200™. This demonstrates a feasible approach for delivery of such nanoparticles in the lung.


Assuntos
Glicina/química , Pulmão/efeitos dos fármacos , Nanopartículas/administração & dosagem , Nanopartículas/química , Células A549 , Linhagem Celular Tumoral , Dextranos/química , Portadores de Fármacos/química , Composição de Medicamentos/métodos , Sistemas de Liberação de Medicamentos/métodos , Excipientes/química , Humanos , Macrófagos/efeitos dos fármacos , Nanopartículas de Magnetita/química , Tamanho da Partícula , Porosidade
15.
Anal Bioanal Chem ; 411(25): 6745-6754, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31482291

RESUMO

In the literature, there are reports of the utilization of various hydrogels to create generic platforms for protein microarray applications. Here, a novel strategy was developed to obtain high-performance microarrays. In it, a dextran hydrogel is used to covalently immobilize oligonucleotides and proteins. This method employs aqueous solutions of dextran methacrylate (Dx-MA), which is a biocompatible photopolymerizable monomer. Capture probes are immobilized inside the hydrogel via a light-induced thiol-acrylate coupling reaction at the same time as the dextran polymer is formed. Hydrogel microarrays based on this technique were prepared on different surfaces, such as a Blu-ray Disk and polycarbonate or alkene-functionalized glass slides, and these systems showed high probe-loading capabilities and good biorecognition yields. This methodology presents advantages such as a low cost, a short analysis time, a low limit of detection, and multiplexing capabilities, among others. Confocal fluorescence microscopy analysis demonstrated that in these hydrogel-based microarrays, receptor immobilization and the biorecognition event occurred within the hydrogel and not merely on the surface.


Assuntos
Dextranos/química , Ácidos Nucleicos Imobilizados/química , Metacrilatos/química , Química Click/métodos , Hidrogéis/química , Ácidos Nucleicos/análise , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Cimento de Policarboxilato/química , Compostos de Sulfidrila/química
16.
ACS Appl Mater Interfaces ; 11(38): 34707-34716, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31482705

RESUMO

It is of great significance to develop biocompatible and degradable gene carriers with stimuli-enhanced gene therapy and imaging function. In this work, low-cytotoxic polycation PGEA (ethanolamine-functionalized poly(glycidyl methacrylate))-functionalized dextran-quantum dot (QD) nanohybrids (DQ-PGEA) were proposed as safe and efficient gene carriers via a facile and feasible method. The highly water-soluble dextran gives the carrier good stability, biocompatibility, and abundant modification sites, while QDs allow fluorescence (FL) imaging. Taking advantage of the pH-responsive self-destruction characteristic introduced by Schiff base linkages, DQ-PGEA nanohybrids could not only result in enhanced gene release but also contribute to the elimination of the carriers. Reduced (nondegradable) DQ-PGEA-R nanohybrids were also synthesized as counterparts to reveal the superiority of the responsive DQ-PGEA carriers. The effectiveness of the as-prepared gene delivery systems was verified adopting the antioncogene p53 in the mouse model of breast cancer. As expected, DQ-PGEA nanohybrids demonstrated a superior gene transfection performance and antitumor inhibition compared with their counterparts. Meanwhile, the gene delivery processes could be tracked in real time to visualize the therapeutic processes and realize FL imaging-guided gene therapy. The current multifunctional stimuli-responsive nanoplatforms with the self-destruction feature are intriguing candidates to achieve enhanced gene therapy for tumor treatment.


Assuntos
Dextranos , Técnicas de Transferência de Genes , Terapia Genética , Neoplasias Mamárias Experimentais , Nanocompostos , Pontos Quânticos , Proteína Supressora de Tumor p53 , Animais , Linhagem Celular Tumoral , Dextranos/química , Dextranos/farmacologia , Células HEK293 , Humanos , Concentração de Íons de Hidrogênio , Neoplasias Mamárias Experimentais/genética , Neoplasias Mamárias Experimentais/metabolismo , Neoplasias Mamárias Experimentais/patologia , Neoplasias Mamárias Experimentais/terapia , Camundongos , Nanocompostos/química , Nanocompostos/uso terapêutico , Ácidos Polimetacrílicos/química , Ácidos Polimetacrílicos/farmacologia , Pontos Quânticos/química , Pontos Quânticos/uso terapêutico , Proteína Supressora de Tumor p53/biossíntese , Proteína Supressora de Tumor p53/genética
17.
Int J Nanomedicine ; 14: 5785-5797, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31440047

RESUMO

Introduction: The targeted delivery of anti-cancer drugs to tumor tissue has been recognized as a promising strategy to increase their therapeutic efficacy and reduce side effects. Mesoporous silica-coated superparamagnetic Fe3O4 nanoparticles (NH2-MSNs), a kind of nanocarrier, can passively enter tumor tissues to enhance the permeability and retention of drugs. However, NH2-MSNs do not specifically bind to cancer cells. This drawback encouraged us to develop a more efficient nanocarrier for cancer therapy. Methods: Herein, we describe the development of an effective nanocarrier based on NH2-MSNs, which were modified with hyaluronic acid on their surface (HA-MSNs) and loaded with doxorubicin (DOX). We have successfully fabricated uniform spherical HA-MSNs nanocarriers. The targeting ability of this delivery system was evaluated through specific uptake by cells and IVIS imaging. Results: DOX-HA-MSNs nanocarriers displayed more dramatic cytotoxic activity against 4T1 breast cancer cells compared to GES-1 gastric mucosa cells. In vivo results revealed that once DOX-HA-MSNs nanocarriers are exposed to an external magnetic field, they could be rapidly attracted to the magnet and effectively cross the cytoplasmic membrane via CD44 receptor-mediated transcytosis. This allows them to access the cancer cell cytoplasm and release DOX based on changes in the physiological environment. Both in vitro and in vivo results demonstrated that the HA-MSNs nanocarriers provided better therapeutic efficacy. Conclusion: The HA-MSNs nanocarriers represent an effective new paradigm to treat cancers due to active targeting to the tumor cells. Moreover, the specific uptake by the tumor effectively protects normal tissues to reduce off-target side effects. The reported findings support further investigation of HA-MSNs for cancer therapy.


Assuntos
Dextranos/química , Sistemas de Liberação de Medicamentos , Ácido Hialurônico/química , Nanopartículas de Magnetita/química , Dióxido de Silício/química , Animais , Linhagem Celular Tumoral , Doxorrubicina/administração & dosagem , Doxorrubicina/farmacologia , Humanos , Nanopartículas de Magnetita/ultraestrutura , Camundongos , Nanopartículas/administração & dosagem , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Espectroscopia Fotoeletrônica , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Ensaios Antitumorais Modelo de Xenoenxerto
18.
J Food Sci ; 84(9): 2421-2431, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31404478

RESUMO

Lutein is incorporated into foods as a natural yellow pigment and nutraceutical. The introduction of lutein into many foods and beverages, however, is problematic because of its strong hydrophobicity and poor chemical stability. In this research, lutein-loaded nanoemulsions were prepared to overcome this problem. Casein-dextran Maillard conjugates or physical complexes were utilized as emulsifiers, while either medium chain triglycerides (MCT) or grape seed oil (GSO) were used as carrier oils. The impact of resveratrol addition on nanoemulsion stability was also examined. The influence of storage temperature, pH, and CaCl2 concentration on the chemical and physical stability of the nanoemulsions was measured. The casein-dextran conjugates were highly effective at improving the physical resistance of the nanoemulsions to environmental stresses, but had a detrimental effect on their color stability. Conversely, nanoemulsions prepared from casein-dextran physical complexes were unstable around the protein's isoelectric point (pH 4.6), as well as upon addition of CaCl2 . Incorporation of resveratrol and GSO into the nanoemulsions decreased lutein degradation and color fading at all temperatures. This study shows that casein-dextran conjugates are highly effective at improving the physical stability of lutein-loaded nanoemulsions, while resveratrol and GSO are effective at improving their chemical stability. PRACTICAL APPLICATION: Lutein can be used by the food industry to create "clean label" and functional food products. The major challenges in incorporating lutein in foods are its poor chemical stability and its high hydrophobicity, which makes it difficult to incorporate. Emulsion-based delivery systems assembled from natural ingredients may address these challenges. In this study, the impact of Maillard conjugates fabricated from caseinate and dextran, as well as resveratrol addition, on the formation and stability of lutein-enriched nanoemulsions was determined. The information obtained from this study will help the formulation of more effective functional foods and beverage products.


Assuntos
Luteína/química , Resveratrol/química , Caseínas/química , Dextranos/química , Composição de Medicamentos , Estabilidade de Medicamentos , Emulsões/química , Temperatura Ambiente
19.
Carbohydr Polym ; 223: 115118, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31426975

RESUMO

New biocompatible amphiphilic block copolymers were prepared using two natural compounds as starting materials, a polysaccharide (dextran) and a bile acid (deoxycholic acid). The copolymers were synthesized by dipolar 1,3-cycloaddition reaction between dextran with azide end groups and deoxycholic acid - oligo(ethylene glycol)s polyester with propargyl end groups. Different copolymer composition were obtained by variation of molecular weights of dextran (Mn 4.5, 8, 15 kDa) and polyester (Mn 2-6 kDa), as well as the length of oligo(ethylene glycol) (2-4 ethylenglycol units) used for polyester synthesis. These copolymers can for micelle like aggregates in aqueous medium with nanometric size (50-600 nm) and spherical form, as assessed by light scattering, atomic force microscopy and transmission electron microscopy. Encapsulation of the hydrophobic drug curcumin in micelles could increase 68,181 times its water solubility, and curcumin release from micelles was slow and with reduced burst effect.


Assuntos
Antineoplásicos/química , Materiais Biocompatíveis/síntese química , Curcumina/química , Ácido Desoxicólico/química , Dextranos/química , Polímeros/síntese química , Tensoativos/síntese química , Materiais Biocompatíveis/química , Cápsulas/química , Liberação Controlada de Fármacos , Interações Hidrofóbicas e Hidrofílicas , Micelas , Conformação Molecular , Tamanho da Partícula , Polímeros/química , Solubilidade , Propriedades de Superfície , Tensoativos/química
20.
Carbohydr Polym ; 223: 115111, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31426984

RESUMO

An exopolysaccharide (EPS)-producing bacterial strain L3 was isolated from Hubei sausage and identified as Lactobacillus sakei via morphological, physiological, biochemical and 16S rDNA analysis. FT-IR spectroscopy and NMR revealed that L3 EPS was a dextran containing d-glucose residues with α-1,6 glycosidic linkage. Rheological studies showed that it had high viscosity at high concentration, low temperature, and acidic pH (pH 3.0). Scanning electron microscopy of the L3 dextran demonstrated a porous and branched morphology, and atomic force microscopy showed lumps of varying height on the rough surface of the L3 EPS polymer. The EPS was thermally stable up to 272°C and could coagulate sucrose-supplemented milk. Together, these results suggested that L3 EPS might have potential applications in food processing and other areas.


Assuntos
Dextranos/biossíntese , Dextranos/isolamento & purificação , Lactobacillus sakei/química , Produtos da Carne/microbiologia , Dextranos/química , Fermentação , Lactobacillus sakei/isolamento & purificação , Lactobacillus sakei/metabolismo , Tamanho da Partícula , Propriedades de Superfície
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA