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Metabolic disease is epidemiologically linked to severe complications upon influenza virus infection, thus vaccination is a priority in this high-risk population. Yet, vaccine responses are less effective in these same hosts. Here we examined how the timing of diet switching from a high-fat diet to a control diet affected influenza vaccine efficacy in diet-induced obese mice. Our results demonstrate that the systemic meta-inflammation generated by high-fat diet exposure limited T cell maturation to the memory compartment at the time of vaccination, impacting the recall of effector memory T cells upon viral challenge. This was not improved with a diet switch post-vaccination. However, the metabolic dysfunction of T cells was reversed if weight loss occurred 4 weeks before vaccination, restoring a functional recall response. This corresponded with changes in the systemic obesity-related biomarkers leptin and adiponectin, highlighting the systemic and specific effects of diet on influenza vaccine immunogenicity.
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Dieta Hiperlipídica , Vacinas contra Influenza , Obesidade , Infecções por Orthomyxoviridae , Animais , Camundongos , Vacinas contra Influenza/imunologia , Vacinas contra Influenza/administração & dosagem , Dieta Hiperlipídica/efeitos adversos , Obesidade/imunologia , Obesidade/metabolismo , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/prevenção & controle , Camundongos Endogâmicos C57BL , Vacinação , Camundongos Obesos , Leptina/metabolismo , Masculino , Feminino , Adiponectina/metabolismo , Linfócitos T/imunologiaRESUMO
OBJECTIVES: The current in vitro study aims to evaluate silk fibroin with and without the addition of graphene as a potential scaffold material for regenerative endodontics. MATERIAL AND METHODS: Silk fibroin (SF), Silk fibroin/graphene oxide (SF/GO) and silk fibroin coated with reduced graphene oxide (SF/rGO) scaffolds were prepared (n = 30). The microarchitectures and mechanical properties of scaffolds were evaluated using field emission scanning electron microscopy (FESEM), pore size and water uptake, attenuated total reflectance fourier transformed infrared spectroscopy (ATR-FTIR), Raman spectroscopy and mechanical compression tests. Next, the study analyzed the influence of these scaffolds on human dental pulp stem cell (hDPSC) viability, apoptosis or necrosis, cell adhesion, odontogenic differentiation marker expression and mineralized matrix deposition. The data were analyzed with ANOVA complemented with the Tukey post-hoc test (p < 0.005). RESULTS: SEM analysis revealed abundant pores with a size greater than 50 nm on the surface of tested scaffolds, primarily between 50 nm and 600 µm. The average value of water uptake obtained in pure fibroin scaffolds was statistically higher than that of those containing GO or rGO (p < 0.05). ATR-FTIR evidenced that the secondary structures did not present differences between pure fibroin and fibroin coated with graphene oxide, with a similar infrared spectrum in all tested scaffolds. Raman spectroscopy showed a greater number of defects in the links in SF/rGO scaffolds due to the reduction of graphene. In addition, adequate mechanical properties were exhibited by the tested scaffolds. Regarding biological properties, hDPSCs attached to scaffolds were capable of proliferating at a rate similar to the control, without affecting their viability over time. A significant upregulation of ALP, ON and DSPP markers was observed with SF/rGO and SF/GO groups. Finally, SF/GO and SF/rGO promoted a significantly higher mineralization than the control at 21 days. SIGNIFICANCE: Data obtained suggested that SF/GO and SF/rGO scaffolds promote hDPSC differentiation at a genetic level, increasing the expression of key osteo/odontogenic markers, and supports the mineralization of the extracellular matrix. However, results from this study are to be interpreted with caution, requiring further in vivo studies to confirm the potential of these scaffolds.
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Fibroínas , Grafite , Humanos , Fibroínas/química , Alicerces Teciduais/química , Engenharia Tecidual/métodos , Grafite/química , Polpa Dentária , Diferenciação Celular , Água , Proliferação de Células , Células-TroncoRESUMO
Pregnant women and infants are considered high-risk groups for increased influenza disease severity. While influenza virus vaccines are recommended during pregnancy, infants cannot be vaccinated until at least six months of age. Passive transfer of maternal antibodies (matAbs) becomes vital for the infant's protection. Here, we employed an ultrasound-based timed-pregnancy murine model and examined matAb responses to distinct influenza vaccine platforms and influenza A virus (IAV) infection in dams and their offspring. We demonstrate vaccinating dams with a live-attenuated influenza virus (LAIV) vaccine or recombinant hemagglutinin (rHA) proteins administered with adjuvant resulted in enhanced and long-lasting immunity and protection from influenza in offspring. In contrast, a trivalent split-inactivated vaccine (TIV) afforded limited protection in our model. By cross-fostering pups, we show the timing of antibody transfer from vaccinated dams to their offspring (prenatal versus postnatal) can shape the antibody profile depending on the vaccine platform. Our studies provide information on how distinct influenza vaccines lead to immunogenicity and efficacy during pregnancy, impact the protection of their offspring, and detail roles for IgG1 and IgG2c in the development of vaccine administration during pregnancy that stimulate and measure expression of both antibody subclasses.
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Human astrovirus is a positive-sense, single-stranded RNA virus. Astrovirus infection causes gastrointestinal symptoms and can lead to encephalitis in immunocompromised patients. Positive-strand RNA viruses typically utilize host intracellular membranes to form replication organelles, which are potential antiviral targets. Many of these replication organelles are double-membrane vesicles (DMVs). Here, we show that astrovirus infection leads to an increase in DMV formation through a replication-dependent mechanism that requires some early components of the autophagy machinery. Results indicate that the upstream class III phosphatidylinositol 3-kinase (PI3K) complex, but not LC3 conjugation machinery, is utilized in DMV formation. Both chemical and genetic inhibition of the PI3K complex lead to significant reduction in DMVs, as well as viral replication. Elucidating the role of autophagy machinery in DMV formation during astrovirus infection reveals a potential target for therapeutic intervention for immunocompromised patients. IMPORTANCE These studies provide critical new evidence that astrovirus replication requires formation of double-membrane vesicles, which utilize class III phosphatidylinositol 3-kinase (PI3K), but not LC3 conjugation autophagy machinery, for biogenesis. These results are consistent with replication mechanisms for other positive-sense RNA viruses suggesting that targeting PI3K could be a promising therapeutic option for not only astrovirus, but other positive-sense RNA virus infections.
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Mamastrovirus , Fosfatidilinositol 3-Quinase , Replicação Viral , Humanos , Autofagia , Classe III de Fosfatidilinositol 3-Quinases/metabolismo , Membranas Intracelulares/metabolismo , Organelas , Fosfatidilinositol 3-Quinase/metabolismo , Vírus de RNA , Mamastrovirus/fisiologia , Transdução de SinaisRESUMO
Human astrovirus is a positive sense, single stranded RNA virus. Astrovirus infection causes gastrointestinal symptoms and can lead to encephalitis in immunocompromised patients. Positive strand RNA viruses typically utilize host intracellular membranes to form replication organelles, which are potential antiviral targets. Many of these replication organelles are double membrane vesicles (DMVs). Here we show that astrovirus infection leads to an increase in DMV formation, and this process is replication-dependent. Our data suggest that astrovirus infection induces rearrangement of endoplasmic reticulum fragments, which may become the origin for DMV formation. Transcriptional data suggested that formation of DMVs during astrovirus infection requires some early components of the autophagy machinery. Results indicate that the upstream class III phosphatidylinositol 3-kinase (PI3K) complex, but not LC3 conjugation machinery, is utilized in DMV formation. Inhibition of the PI3K complex leads to significant reduction in viral replication and release from cells. Elucidating the role of autophagy machinery in DMV formation during astrovirus infection reveals a potential target for therapeutic intervention for immunocompromised patients. Importance: These studies provide critical new evidence that astrovirus replication requires formation of double membrane vesicles, which utilize class III PI3K, but not LC3 conjugation autophagy machinery for biogenesis. These results are consistent with replication mechanisms for other positive sense RNA viruses. This suggests that targeting PI3K could be a promising therapeutic option for not only astrovirus, but other positive sense RNA virus infections.
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Silk gut fibers were produced from the silkworm Samia cynthia ricini silk glands by the usual procedure of immersion in a mildly acidic solution and subsequent stretching. The morphology of the silk guts was assessed by scanning electron microscopy, and their microstructure was assessed by infrared spectroscopy and X-ray diffraction. It was found that both naturally spun and Samia silk guts share a common semicrystalline microstructure. The mechanical characterization of the silk guts revealed that these fibers show an elastomeric behavior when tested in water, and exhibit a genuine ground state to which the fiber may revert independently of its previous loading history. In spite of its large cross-sectional area compared with naturally spun silk fibers, Samia silk guts show values of work to fracture up to 160 MJ m-3, much larger than those of most of their natural counterparts, and establish a new record value for this parameter in silk guts.
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Bombyx , Seda , Animais , Seda/química , Espectrofotometria Infravermelho , Difração de Raios XRESUMO
High-performance fibroin fibres are ideal candidates for the manufacture of scaffolds with applications in tissue engineering due to the excellent mechanical properties and optimal biocompatibility of this protein. In this work, the manufacture of high-strength fibres made from the silk glands of Samia cynthia ricini is explored. The glands were subjected to soaking in aqueous dissolutions of acetic acid and stretched to manufacture the fibres. The materials produced were widely characterized, in terms of morphology, mechanical properties, crystallinity and content of secondary structures, comparing them with those produced by the standard procedure published for Bombyx mori. In addition, mechanical properties and biocompatibility of a braided scaffold produced from these fibres was evaluated. The results obtained show that the fibres from B. mori present a higher degree of crystallinity than those from S. c. ricini, which is reflected in higher values of elastic modulus and lower values of strain at break. Moreover, a decrease in the elongation values of the fibres from S. c. ricini was observed as the concentration of acetic acid was increased during the manufacture. On the other hand, the study of the braided scaffolds showed higher values of tensile strength and strain at break in the case of S. c. ricini materials and similar values of elastic modulus, compared to those of B. mori, displaying both scaffolds optimal biocompatibility using a fibroblast cell line.
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Bombyx , Fibroínas , Manduca , Animais , Bombyx/metabolismo , Fibroínas/química , Manduca/metabolismo , Estrutura Secundária de Proteína , Seda/química , Engenharia TecidualRESUMO
Pregnant women, newborns, and infants under six months old are at the highest risk of developing severe and even fatal influenza. This risk is compounded by the inability to vaccinate infants under six months, highlighting the importance of vertically transferred immunity. This review identifies novel insights that have emerged from recent studies using animal models of pregnancy and vaccination. We also discuss the knowledge obtained using existing clinical trials that have evaluated influenza-specific serological responses in pregnant women and how these responses may impact early life immunity. We delineate the mechanisms involved in transferring specific maternal antibodies and discuss the consequences for early life immunity. Most importantly, we highlight the need for continued research using pregnant animal models and the inclusion of pregnant women, a commonly neglected population, when evaluating novel vaccine platforms to better serve and treat communicable diseases.
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Spider mites constitute an assemblage of well-known pests in agriculture, but are less known for their ability to spin silk of nanoscale diameters and high Young's moduli. Here, we characterize silk of the gorse spider mite Tetranychus lintearius, which produces copious amounts of silk with nano-dimensions. We determined biophysical characteristics of the silk fibres and manufactured nanoparticles and biofilm derived from native silk. We determined silk structure using attenuated total reflectance Fourier transform infrared spectroscopy, and characterized silk nanoparticles using field emission scanning electron microscopy. Comparative studies using T. lintearius and silkworm silk nanoparticles and biofilm demonstrated that spider mite silk supports mammalian cell growth in vitro and that fluorescently labelled nanoparticles can enter cell cytoplasm. The potential for cytocompatibility demonstrated by this study, together with the prospect of recombinant silk production, opens a new avenue for biomedical application of this little-known silk.
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Materiais Biocompatíveis , Teste de Materiais , Nanopartículas/química , Seda/química , Tetranychidae/química , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacocinética , Materiais Biocompatíveis/farmacologia , Linhagem Celular , Módulo de Elasticidade , Camundongos , Microscopia Eletrônica de Varredura , Nanopartículas/ultraestruturaRESUMO
We have previously demonstrated that endothelial targeting of gold nanoparticles followed by external beam irradiation can cause specific tumor vascular disruption in mouse models of cancer. The induced vascular damage may lead to changes in tumor physiology, including tumor hypoxia, thereby compromising future therapeutic interventions. In this study, we investigate the dynamic changes in tumor hypoxia mediated by targeted gold nanoparticles and clinical radiation therapy (RT). By using noninvasive whole-body fluorescence imaging, tumor hypoxia was measured at baseline, on day 2 and day 13, post-tumor vascular disruption. A 2.5-fold increase (P<0.05) in tumor hypoxia was measured two days after combined therapy, resolving by day 13. In addition, the combination of vascular-targeted gold nanoparticles and radiation therapy resulted in a significant (P<0.05) suppression of tumor growth. This is the first study to demonstrate the tumor hypoxic physiological response and recovery after delivery of vascular-targeted gold nanoparticles followed by clinical radiation therapy in a human non-small cell lung cancer athymic Foxn1nu mouse model.
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Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Nanopartículas Metálicas/uso terapêutico , Hipóxia Tumoral , Células A549 , Animais , Carcinoma Pulmonar de Células não Pequenas/irrigação sanguínea , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/radioterapia , Ouro/uso terapêutico , Humanos , Neoplasias Pulmonares/irrigação sanguínea , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/radioterapia , Camundongos , Camundongos Nus , Imagem Óptica/métodos , Hipóxia Tumoral/efeitos dos fármacos , Hipóxia Tumoral/efeitos da radiação , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
PURPOSE: Tumor-associated antigens are a promising target of immunotherapy approaches for cancer treatments but rely on sufficient expression of the target antigen. This study investigates the expression of the carcinoembryonic antigen (CEA) on the surface of irradiated lung cancer cells in vitro using gold nanoparticles as radio-enhancer. METHODS: Human lung carcinoma cells A549 were irradiated and expression of CEA on the cell surface measured by flow cytometry 3 h, 24 h, and 72 h after irradiation to doses of 2 Gy, 6 Gy, 10 Gy, and 20 Gy in the presence or absence of 0.1 mg/ml or 0.5 mg/ml gold nanoparticles. CEA expression was measured as median fluorescent intensity and percentage of CEA-positive cells. RESULTS: An increase in CEA expression was observed with both increasing radiation dose and time. There was doubling in median fluorescent intensity 24 h after 20 Gy irradiation and 72 h after 6 Gy irradiation. Use of gold nanoparticles resulted in additional significant increase in CEA expression. Change in cell morphology included swelling of cells and increased internal complexity in accordance with change in CEA expression. CONCLUSIONS: This study showed an increase in CEA expression on human lung carcinoma cells following irradiation. Increase in expression was observed with increasing radiation dose and in a time dependent manner up to 72 h post irradiation. The results further showed that gold nanoparticles can significantly increase CEA expression following radiotherapy.
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Neoplasias Pulmonares , Nanopartículas Metálicas , Antígeno Carcinoembrionário , Ouro , Humanos , Pulmão , Neoplasias Pulmonares/radioterapiaRESUMO
INTRODUCTION: Recent studies indicate that alkaline phosphatase (ALP) may affect expression and activity of fatty acid (FA) transport proteins in placenta and other tissues. OBJECTIVE: To evaluate if disturbed FA profile in offspring of gestational diabetes mellitus (GDM) with different maternal pregestational weight could be related to maternal or neonatal ALP. METHODS: Prospective observational study of pregnant women recruited in the third trimester (25 controls, 23 lean-GDM, 20 obese-GDM). Fetal ultrasound was performed. At delivery, FAs were analyzed in placenta, maternal, and venous cord blood. Western blotting analysis of lipid carriers was performed in placenta. RESULTS: Newborns from obese-GDM tended to higher birthweight (p = 0.059) than those from both lean-GDM and controls. ALP in maternal blood tended to be lower in GDM (p = 0.170) while increased significantly in cord blood of obese-GDM with respect to controls (p = 0.039). Saturated FA percentages in cord blood were significantly higher (p < 0.000), while polyunsaturated FA (PUFA) percentages were lower (p = 0.003) in both GDM, which could be due to a lower expression of major family domain 2a receptor (MFSD2a) in the placenta. Plasma ALP in the offspring of obese-GDM was inversely associated to cord essential PUFAs (ß = -6.18, p = 0.005) and to placental MFSD2a (ß = -38.46, p = 0.014). CONCLUSIONS: Cord PUFA and placental MFSD2a are decreased in both lean and obese-GDM pregnancies. Higher ALP in cord blood of obese-GDM could play a role in the FA levels in these pregnancies.
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Fosfatase Alcalina/sangue , Diabetes Gestacional/enzimologia , Ácidos Graxos Insaturados/análise , Sangue Fetal/enzimologia , Obesidade/enzimologia , Adulto , Estudos de Casos e Controles , Ácidos Graxos Insaturados/sangue , Feminino , Sangue Fetal/química , Humanos , Obesidade/complicações , Placenta/química , Gravidez , Terceiro Trimestre da Gravidez , Estudos ProspectivosRESUMO
Stifling treatments are applied to silk cocoons in order to kill the pupae, preventing the emergence of moths and allowing to preserve the silk during long periods of time. All of them involve the application of aggressive steps, such as sun exposure, hot steam from boiling water or hot air, during hours or even days. None of the scientific articles related to silk fibroin biomaterials has previously taken into account this fact in its section of materials and methods. In this work, the consequences of the stifling treatments most commonly used by the silk producing countries and companies are explored in depth, using fibroin films as biomaterial model. The protein degradation (visualised by SDS-PAGE) was dramatically increased in all the fibroin dissolutions produced from stifled cocoons; heavy and light chains of fibroin were specially degraded, reducing their presence along the lanes of the gel compared to the negative control (untreated fresh cocoons). Structural changes are also described for annealed silk fibroin films. The ß-sheet content, analysed by means of infrared spectroscopy, was significantly higher when stifling was performed at higher temperature (70 °C and 85 °C). It is also exposed the impact of the stifling on the mechanical properties of the materials. Tensile strength and strain at break values were detected as significantly lower when this procedure was carried out by means of dry heat (85 °C) and sun exposure. On the other hand, and contrary to expectations, the proliferation of fibroblasts growing on the materials was improved by all the different stifling methods, compared to negative control, being this improvement, especially accentuated, on the films produced with fibroin purified from cocoons treated with dry heat.
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Materiais Biocompatíveis/química , Bombyx/química , Fibroínas/química , Seda/química , Animais , Técnicas de Cultura de Células/instrumentação , Proliferação de Células , Células Cultivadas , Eletroforese em Gel de Poliacrilamida , Fibroblastos/citologia , Humanos , Proteínas de Insetos/química , Pupa/química , Espectroscopia de Infravermelho com Transformada de Fourier , Resistência à TraçãoRESUMO
Tendon and ligament tissue engineering require scaffolds for the treatment of various conditions in the medical field. These must meet requirements such as high tensile strength, biocompatibility, fast and stable repair and a rate of degradation that allows the repair of the damaged tissue. In this work, we propose the use of silkworm gut fiber braids as materials to temporarily replace and repair this type of tissues. The mechanical characterization of the braids made with different number of silk gut fibers is provided, as well as a descriptive analysis of the proliferation and adhesion of cultures of adult human mesenchymal stem cells from bone marrow and fibroblasts (L929) on the braids. As expected, the breaking force increases linearly in the scaffold with the number of fibers, thus being a parameter adaptable to the specific requirements of the tissue to repair and the animal model of study. On the other hand, in all of the cases studied, the values obtained for the elastic modulus of the hydrated fibers were in the range of the ones reported for various human tendons and ligaments. Moreover, the scaffold demonstrated excellent biocompatibility in vitro, allowing the adhesion and proliferation, in the same culture conditions, of the two cell types studied, therefore posing as an ideal candidate to be employed in future in vivo studies that allow elucidating its behavior in the articular environment or extra-articular tendinous areas. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res B Part B: 2019. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2209-2215, 2019.
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Bombyx , Intestinos/química , Ligamentos , Células-Tronco Mesenquimais , Tendões , Engenharia Tecidual , Alicerces Teciduais/química , Animais , Linhagem Celular , Ligamentos/citologia , Ligamentos/metabolismo , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Camundongos , Tendões/citologia , Tendões/metabolismoRESUMO
Novel approaches to neural research require biocompatible materials capable to act as electrode structures or scaffolds for tissue engineering in order to stimulate or restore the functionality of damaged tissues. This work offers promising results that indicate the potential use of electrospun silk fibroin (SF) scaffolds coated with reduced graphene oxide (rGO) in this sense. The coated material becomes conductor and electroactive. A complete characterisation of SF/rGO scaffolds is provided in terms of electrochemistry, mechanical behaviour and chemical conformation of fibroin. The excellent biocompatibility of this novel material is proved with cultures of PC-12 cells. The coating with rGO improved the adhesion of cells in comparison with cells growing onto the surface of pure SF scaffolds. Also, the use of SF/rGO scaffolds combined with electrical stimulation promoted the differentiation into neural phenotypes reaching comparable or even superior levels to those obtained by means of the traditional treatment with neural growth factor (NGF).
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Fibroínas/química , Animais , Materiais Biocompatíveis , Estimulação Elétrica , Grafite , Crescimento Neuronal , Células PC12 , Ratos , Seda , Engenharia Tecidual , Alicerces TeciduaisRESUMO
BACKGROUND & AIMS: Maternal-fetal transfer of docosahexaenoic acid (DHA) is impaired by gestational diabetes mellitus (GDM), but the underlying mechanisms are still unknown. MFSD2a was recently recognized as a lyso-phospholipid (lyso-PL) transporter that facilitates DHA accretion in brain. The role of this transporter in placenta is uncertain. We evaluated effects of GDM and its treatment (diet or insulin) on phospholipid species, fatty acid profile in women, cord blood and placental fatty acid carriers. METHODS: Prospective observational study of pregnant women recruited in the third trimester (25 controls, 23 GDM-diet, 20 GDM-insulin). Fetal ultrasound was performed at gestational week 38. At delivery, maternal and neonatal anthropometry was performed, and fatty acids in total lipids and phospholipid species were analyzed in placenta, maternal and venous cord blood. Western-blot analyses were performed for placental fatty acid carriers. RESULTS: Fetal abdominal circumference z-score at 38 weeks tended to higher values in GDM (P = 0.071), pointing toward higher fetal fat accretion in these babies. DHA percentage in cord serum total lipids (P = 0.029) and lyso-PL (P = 0.169) were reduced in GDM. Placental MFSD2a was reduced in both GDM groups and was positively correlated to DHA values in cord serum total lipids (r = 0.388, P = 0.003). Among established placental lipid carriers, only FATP4 was correlated to DHA concentration in placental lyso-PL. In all compartments, DHA percentage was inversely correlated to fetal abdominal circumference. CONCLUSIONS: In offspring of women with GDM treated either with diet or insulin, higher fetal fat accretion and lower placental MFSD2a contribute to reduce DHA availability. Lyso-PL appear to contribute to materno-fetal DHA transport.
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Diabetes Gestacional/dietoterapia , Diabetes Gestacional/tratamento farmacológico , Ácidos Docosa-Hexaenoicos/sangue , Sangue Fetal/química , Placenta/metabolismo , Proteínas Supressoras de Tumor/genética , Adolescente , Adulto , Glicemia/metabolismo , Estudos de Casos e Controles , Diabetes Gestacional/sangue , Dieta , Proteínas de Transporte de Ácido Graxo/sangue , Proteínas de Transporte de Ácido Graxo/genética , Ácidos Graxos/sangue , Feminino , Feto/metabolismo , Idade Gestacional , Humanos , Insulina/sangue , Insulina/uso terapêutico , Masculino , Fosfolipídeos/sangue , Gravidez , Terceiro Trimestre da Gravidez , Estudos Prospectivos , Simportadores , Adulto JovemRESUMO
This article describes how silk fibroin nanoparticles (SFNs) are capable of adsorbing and releasing quercetin (Q) and how its integrity is highly preserved, as confirmed by antioxidant activity assays. Q loading onto SFNs was optimized in terms of the Q/SFN ratio (w/w), time of adsorption and solvent mixture. Quercetin-loaded silk fibroin nanoparticles (QSFNs) were characterized using the dynamic light scattering technique to measure the diameter (Z-Average) and Z-potential (ζ). Loaded particles were slightly bigger than the SFNs, while their ζ was less negative. The antioxidant activity against DPPH showed that the Q loaded in QSFNs not only retains the antioxidant activity but also has a synergistic scavenging activity due the intrinsic antioxidant activity of the SF. The drug loading content (DLC) and the encapsulation efficiency (EE) varied with the relation between Q and SFN in the loading solution. The sustained release of Q occurred throughout the experiment both in phosphate buffer saline (pH 7.4) and simulated intestinal fluid (pH 6.8). The results point to SFNs as promising candidates for Q loading, transport and gastrointestinal delivery with potential applications in nanomedicine, while retaining their nano-size and their antioxidant properties.
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Antioxidantes/química , Sistemas de Liberação de Medicamentos , Fibroínas/química , Nanopartículas/química , Quercetina/química , Adsorção , Compostos de Bifenilo/química , Liberação Controlada de Fármacos , Fibroínas/ultraestrutura , Microscopia Eletrônica de Varredura , Nanopartículas/ultraestrutura , Picratos/químicaRESUMO
Chemically exfoliated MoS2 (ce-MoS2) has emerged in recent years as an attractive two-dimensional material for use in relevant technological applications, but fully exploiting its potential and versatility will most probably require the deployment of appropriate chemical modification strategies. Here, we demonstrate that extensive covalent functionalization of ce-MoS2 nanosheets with acetic acid groups (â¼0.4 groups grafted per MoS2 unit) based on the organoiodide chemistry brings a number of benefits in terms of their processability and functionality. Specifically, the acetic acid-functionalized nanosheets were furnished with long-term (>6 months) colloidal stability in aqueous medium at relatively high concentrations, exhibited a markedly improved temporal retention of catalytic activity toward the reduction of nitroarenes, and could be more effectively coupled with silver nanoparticles to form hybrid nanostructures. Furthermore, in vitro cell proliferation tests carried out with murine fibroblasts suggested that the chemical derivatization had a positive effect on the biocompatibility of ce-MoS2. A hydrothermal annealing procedure was also implemented to promote the structural conversion of the functionalized nanosheets from the 1T phase that was induced during the chemical exfoliation step to the original 2H phase of the starting bulk material, while retaining at the same time the aqueous colloidal stability afforded by the presence of the acetic acid groups. Overall, by highlighting the benefits of this type of chemical derivatization, the present work should contribute to strengthen the position of ce-MoS2 as a two-dimensional material of significant practical utility.
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Nanopores are a promising platform in next generation DNA sequencing. In this platform, an individual DNA strand is threaded into nanopore using an electric field, and enzyme-based ratcheting is used to move the strand through the detector. During this process the residual ion current through the pore is measured, which exhibits unique levels for different base combinations inside the pore. While this approach has shown great promise, accuracy is not optimal because the four bases are chemically comparable to one another, leading to small differences in current obstruction. Nucleobase-specific chemical tagging can be a viable approach to enhancing the contrast between different bases in the sequence. Herein we show that covalent modification of one or both of the pyrimidine bases by an osmium bipyridine complex leads to measureable differences in the blockade amplitudes of DNA molecules. We qualitatively determine the degree of osmylation of a DNA strand by passing it through a solid-state nanopore, and are thus able to gauge T and C base content. In addition, we show that osmium bipyridine reacts with dsDNA, leading to substantially different current blockade levels than exhibited for bare dsDNA. This work serves as a proof of principle for nanopore sequencing and mapping via base-specific DNA osmylation.
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Citosina/química , DNA/análise , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Osmio/química , Análise de Sequência de DNA/métodos , Timina/química , 2,2'-Dipiridil/química , DNA/química , Eletricidade , Nanoporos , Oligonucleotídeos/química , Coloração e Rotulagem/métodosRESUMO
The functionality of the placenta may affect neonatal adiposity and fetal levels of key nutrients such as long-chain polyunsaturated fatty acids. Fetal macrosomia and its complications may occur even in adequately controlled gestational diabetic (GDM) mothers, suggesting that maternal glycemia is not the only determinant of fetal glycemic status and wellbeing. We studied in vivo the placental transfer of fatty acids (FA) labeled with stable isotopes administered to 11 control and 9 GDM pregnant women (6 treated with insulin). Subjects received orally ¹³C-palmitic, ¹³C-oleic, and ¹³C-linoleic acids and ¹³C-docosahexaenoic acid (¹³C-DHA) 12 h before an elective caesarean section. FA were quantified by gas chromatography and ¹³C enrichments by gas chromatography-isotope ratio mass spectrometry. The ¹³C-FA concentration was higher in total lipids of maternal plasma in GDM patients versus controls, except for ¹³C-DHA. Moreover, ¹³C-DHA showed a lower placenta/maternal plasma ratio in GDM patients versus controls and a significantly lower cord/maternal plasma ratio. Other FA ratios studied were not different between GDM and controls. A disturbed ¹³C-DHA placental uptake occurred in GDM patients treated with diet or insulin, while the latter also had lower ¹³C-DHA levels in the venous cord. The tracer study pointed towards an impaired placental DHA uptake as a critical step, while the transfer of other ¹³C-FA was less affected. Patients with GDM treated with insulin could also have a greater fetal fat storage, which may have contributed to the reduced ¹³C-DHA in the venous cord observed. The DHA transfer to the fetus was reduced in GDM pregnancies compared to controls. This might have an influence on fetal neurodevelopment and long-term consequences for the child.