Abstract Graphene oxide (GO) is considered to be a promising nanomaterial for biomedical applications due to its small two-dimensional shape besides its electrical and mechanical properties. However, ...only a few data concerning the cell responses to this material have been described and the GO biocompatibility has not been yet fully assessed. In the present study, graphene oxide nanosheets (GOs) decorated with 1-arm (1-GOs) and 6-arm (6-GOs) poly(ethylene glycol-amine) (PEG) have been incubated with cultured Saos-2 osteoblasts, MC3T3-E1 preosteoblasts and RAW-264.7 macrophages to analyze several key cell markers for in vitro biocompatibility evaluation. The results demonstrate that, after internalization, GO nanosheets are localized on F-actin filaments inducing cell-cycle alterations, apoptosis and oxidative stress in these cell types. The observed GOs effects must be considered in further studies focused on photothermal cancer therapy as a synergistic factor.
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•Macrophage/lymphocyte response to graphene oxide nanosheets (GOs) was evaluated.•GOs localized on F-actin filaments of RAW macrophages increase TNF-α release.•GOs reduced primary ...immune cell proliferation in the presence of specific stimuli.•GOs did not induce proinflammatory cytokine secretion on primary immune cells.•These weak inflammation properties can be positive for hyperthermia cancer therapy.
Graphene oxide (GO) has attracted the scientific community attention due to its novel properties and wide range of potential applications including hyperthermia cancer therapy. However, little is known about the GO effects on the immune function which involves both innate and adaptive defence mechanisms through the activation of different cell populations and secretion of several cytokines. The effect of different GO nanosheets designed for hyperthermia cancer therapy on macrophage and lymphocyte function should be determined before using GO for this application.
The effects of GO nanosheets with 1 (1-GOs) and 6 arms (6-GOs) of polyethylene glycol on RAW-264.7 macrophages and primary splenocytes (as approximation to the in vivo situation) were evaluated through the proinflammatory cytokine secretion and the modulation of cell proliferation in the presence of specific stimuli for either T-lymphocytes (concanavalin A, anti-CD3 antibody) or B-lymphocytes/macrophages (lipopolysaccharide).
6-GOs significantly increased the secretion of TNF-α by RAW-264.7 macrophages without alteration of IL-6 and IL-1β levels. The treatment of primary splenocytes with 1-GOs and 6-GOs in the presence of concanavalin A, anti-CD3 antibody and lipopolysaccharide, produced significant dose-dependent decreases of cell proliferation and IL-6 levels, revealing weak inflammatory properties of GOs which are favourable for hyperthermia cancer therapy.
Graphene and its derivatives are very promising nanomaterials for biomedical applications and are proving to be very useful for the preparation of scaffolds for tissue repair. The response of immune ...cells to these graphene-based materials (GBM) appears to be critical in promoting regeneration, thus, the study of this response is essential before they are used to prepare any type of scaffold. Another relevant factor is the variability of the GBM surface chemistry, namely the type and quantity of oxygen functional groups, which may have an important effect on cell behavior. The response of RAW-264.7 macrophages to graphene oxide (GO) and two types of reduced GO, rGO15 and rGO30, obtained after vacuum-assisted thermal treatment of 15 and 30 min, respectively, was evaluated by analyzing the uptake of these nanostructures, the intracellular content of reactive oxygen species, and specific markers of the proinflammatory M1 phenotype, such as CD80 expression and secretion of inflammatory cytokines TNF-α and IL-6. Our results demonstrate that GO reduction resulted in a decrease of both oxidative stress and proinflammatory cytokine secretion, significantly improving its biocompatibility and potential for the preparation of 3D scaffolds able of triggering the appropriate immune response for tissue regeneration.
This work reports a computational study, focused on graphene (G) and graphene oxide (GO) interfaces with titanium dioxide (TiO2), and an experimental assay on the photocatalytic activity of TiO2/G ...and TiO2/GO nanocomposites in the degradation of two different pollutants: methylene blue and ciprofloxacin. Both carbon nanostructures were compared due to their different chemical structure: GO is a G derivative with oxygen functional groups which should promote a closer chemical interaction with TiO2 nanoparticles. Computational models of the fundamental properties of the composites indicated potentially improved photocatalytic activity compared to TiO2, namely lower band gaps and charge carrier segregation at the interfaces. These fundamental properties match qualitatively experimental results on methylene blue, which was more effectively degraded by TiO2/G and TiO2/GO nanocomposites than by pure TiO2 under UV light. In contrast, the same nanocomposites were found to be less efficient to degrade ciprofloxacin than pure TiO2 under visible and UV light. Therefore, this work showcases the relevance of an efficient matching between the catalyst and the molecular properties and structure of the pollutant.
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•Computational studies (DFTB+) for the calculation of the G/TiO2 and GO/TiO2 interfaces.•Efficient photocatalytic degradation of methylene blue with G/TiO2 and GO/TiO2.•Relevant comparison between computational and experimental data.•Reveals the importance of physical-chemical properties to match catalyst/pollutant.
The observations from the Juno spacecraft in polar orbit of Jupiter provide for the first time a complete view of Jupiter's radio emissions from all latitudes. Characterizing the latitudinal ...distribution of radio emissions' occurrence and intensity is a useful step for elucidating their origin. Here, we analyze for that purpose the first 3 years of observations from the Waves experiment on the Juno spacecraft (mid‐2016 to mid‐2019). Two prerequisites for the construction of the latitudinal distribution of intensities for each Jovian radio component are (a) to work with absolute flux densities and (b) to be able to associate each radio measurement with a specific radio component. Accordingly, we develop a method to convert the Juno/Waves data in flux densities and then we build a catalog of all Jovian radio components over the first 3 years of Juno's orbital mission. From these, we derive occurrence and intensity distributions versus observer's latitude and frequency for each component; these will be the basis for future detailed studies and interpretations of each component's characteristics and origin.
Key Points
We build a processing pipeline of Juno/Waves data that include conversion to absolute flux densities
We build a catalog of all Jovian radio components over the first 3 years of Juno's orbital mission
We derive occurrence and intensity distributions versus observer's latitude and frequency for each component
Among the wide range of strategies to target skin repair/regeneration, tissue engineering (TE) with stem cells at the forefront, remains as the most promising route. Cell sheet (CS) engineering is ...herein proposed, taking advantage of particular cell–cell and cell–extracellular matrix (ECM) interactions and subsequent cellular milieu, to create 3D TE constructs to promote full-thickness skin wound regeneration. Human adipose derived stem cells (hASCs) CS were obtained within five days using both thermoresponsive and standard cell culture surfaces. hASCs-based constructs were then built by superimposing three CS and transplanted into full-thickness excisional mice skin wounds with delayed healing. Constructs obtained using thermoresponsive surfaces were more stable than the ones from standard cell culture surfaces due to the natural adhesive character of the respective CS. Both CS-generating strategies lead to prolonged hASCs engraftment, although no transdifferentiation phenomena were observed. Moreover, our findings suggest that the transplanted hASCs might be promoting neotissue vascularization and extensively influencing epidermal morphogenesis, mainly through paracrine actions with the resident cells. The thicker epidermis, with a higher degree of maturation characterized by the presence of rete ridges-like structures, as well as a significant number of hair follicles observed after transplantation of the constructs combining the CS obtained from the thermoresponsive surfaces, reinforced the assumptions of the influence of the transplanted hASCs and the importance of the higher stability of these constructs promoted by cohesive cell–cell and cell–ECM interactions. Overall, this study confirmed the potential of hASCs CS-based constructs to treat full-thickness excisional skin wounds and that their fabrication conditions impact different aspects of skin regeneration, such as neovascularisation, but mainly epidermal morphogenesis.
•Bacterial cellulose/graphene oxide (BC/GO) aerogels were prepared by solvent mixing.•A small amount of DMSO addition during hydrogel formation allow pores orientation.•BC/GO reduced with NH3 ...(gas-phase) show enhanced mechanical and thermal performance.•The reduced BC/GO aerogels present notable values of electric conductivity.
We present a novel method for processing bacterial cellulose/graphene oxide (BC/GO) aerogels with multifunctional properties. The addition of a small amount of dimethyl sulfoxide (DMSO) to the aqueous dispersion of the nanomaterials during the gelification process affected the water freezing temperature of the system and thereby affecting the porous structure of the aerogel obtained after liophilization. The possibility to obtain small and elongated pore with axial orientation allowed a significant improvement of the structural stability of the aerogels. Moreover, the aerogels reduction by thermal treatment with ammonia gas induced crosslinking between the different nanophases, thus given an incremental factor for the mechanical performance of the aerogels under harsh conditions. The resulting aerogels also showed significant improvements in terms of thermal stability and electrical conductivity. These multifunctional BC/GO aerogels present high potential as sustainable and ecological alternative materials for lightweight packaging, filters for atmosphere and water treatment, or energy applications.
Cellulose/Ag nanocomposites were prepared using two distinct methodologies and two cellulose substrates: vegetable and bacterial cellulose. These nanocomposites were characterized in terms of their ...morphology and chemical composition. Detailed studies on the antibacterial activity of these materials were carried out for Bacillus subtilis, Staphylococcus aureus and Klebsiella pneumoniae. Silver nanoparticles present in the cellulosic fibers in concentrations as low as 5.0x10(-4)wt.% make these nanocomposites effective antibacterial materials. We anticipate that the versatile use of these cellulose-based nanocomposites can bring a promising strategy to produce a wide range of interesting materials where antibacterial properties are crucial.
Congenital disorders of glycosylation (CDG) are a rapidly growing family of genetic diseases caused by defects in glycosylation. Nearly 100 CDG types are known so far. Patients present a great ...phenotypic diversity ranging from poly- to mono-organ/system involvement and from very mild to extremely severe presentation. In this literature review, we summarize the liver involvement reported in CDG patients. Although liver involvement is present in only a minority of the reported CDG types (22 %), it can be debilitating or even life-threatening. Sixteen of the patients we collated here developed cirrhosis, 10 had liver failure. We distinguish two main groups: on the one hand, the CDG types with predominant or isolated liver involvement including MPI-CDG, TMEM199-CDG, CCDC115-CDG, and ATP6AP1-CDG, and on the other hand, the CDG types associated with liver disease but not as a striking, unique or predominant feature, including PMM2-CDG, ALG1-CDG, ALG3-CDG, ALG6-CDG, ALG8-CDG, ALG9-CDG, PGM1-CDG, and COG-CDG. This review aims to facilitate CDG patient identification and to understand CDG liver involvement, hopefully leading to earlier diagnosis, and better management and treatment.
Selected bacterial strains were immobilised on the surface of hydroxyapatite (Ca10(PO4)6(OH)2 – HAp) of natural origin (fish bones). The capacity of the material, alone and in combination with the ...bacterial strains to act as heavy metal removers from aqueous streams was assessed. Pseudomonas fluorescens (S3X), Microbacterium oxydans (EC29) and Cupriavidus sp. (1C2) were chosen based on their resistance to heavy metals and capacity of adsorbing the metals.
These systems were tested using solutions of Zn(II), Cd(II) and in solutions containing both metals. A synergistic effect between the strains and HAp, which is effective in removing the target heavy metals on its own, was observed, as the combination of HAp with the bacterial strains led to higher adsorption capacity for both elements.
For the solutions containing only one metal the synergistic effect was greater for higher metal concentrations; 1C2 and EC29 were the most effective strains for Zn(II) and Cd(II) respectively, while S3X was less effective. Overall, an almost four-fold increase was observed for the maximum adsorption capacity for Zn(II) when 1C2 was employed – 0.433 mmol/g in comparison of 0.121 mmol/g for the unmodified HAp. For Cd(II), on the other hand, an almost three-fold increase was registered with EC29 bacterial strain – 0.090 vs 0.036 mmol/g for the unmodified HAp. When the solutions containing both metals were tested, the effect was more marked for lower concentrations.
► Bacterial strains were successfully immobilised on a hydroxyapatite (HAp) surface. ► The combined HAp + bacteria systems were used for removal of Zn(II) and Cd(II). ► The removal efficiency was higher for both metals if compared with unmodified HAp. ► Different strains showed different abilities for metals removal.
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