Numerous applications exist for graphene-based materials, such as graphene oxide (GO) nanosheets. Increased concentrations of GO nanosheets in the environment have the potential to have a large ...negative effect on the aquatic environment, with consequences for benthic organisms, such as polychaetes. The polychaete Hediste diversicolor mobilises the sediments, hence altering the availability of contaminants and the nutrients biogeochemical cycle. As such, this study proposes to assess the effects of different GO nanosheet concentrations on the behaviour, feeding activity, mucus production, regenerative capacity, antioxidant status, biochemical damage and metabolism of H. diversicolor. This study evidenced that H. diversicolor exposed to GO nanosheets had a significantly lower ability to regenerate their bodies, took longer to feed and burrow into the sediment and produced more mucus. Membrane oxidative damage (lipid peroxidation) increased in exposed specimens. The increased metabolic rate (ETS) evidenced a higher energy expenditure in exposed organisms (high use of ready energy sources – soluble sugars) to fight the toxicity induced by GO nanosheets, such as SOD activity. The increase in SOD activity was enough to reduce reactive oxygen species (ROS) induced by GO on cytosol at the lowest concentrations, avoiding the damage on proteins (lower PC levels), but not on membranes (LPO increase). This study revealed that the presence of GO nanosheets, even at the lower levels tested, impaired behavioural, physiological, and biochemical traits in polychaetes, suggesting that the increase of this engineered nanomaterial in the environment can disturb these benthic organisms, affecting the H. diversicolor population. Moreover, given the important role of this group of organisms in coastal and estuarine food webs, the biogeochemical cycle of nutrients, and sediment oxygenation, there is a real possibility for repercussions into the estuarine community.
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•Exposure to GO increased feeding and burrowing time and mucus production.•Regeneration capacity significantly diminished in organisms exposed to GO.•Exposure to GO increased the metabolic rate (ETS) and decreased sugars content.•Membrane damage (LPO) was observed in polychaetes exposed to lower GO concentrations.
Graphene oxide (GO) assists a diverse set of promising routes to build bioactive neural microenvironments by easily interacting with other biomaterials to enhance their bulk features or, ...alternatively, self-assembling toward the construction of biocompatible systems with specific three-dimensional (3D) geometries. Herein, we first modulate both size and available oxygen groups in GO nanosheets to adjust the physicochemical and biological properties of polycaprolactone–gelatin electrospun nanofibrous systems. The results show that the incorporation of customized GO nanosheets modulates the properties of the nanofibers and, subsequently, markedly influences the viability of neural progenitor cell cultures. Interestingly, the partially reduced GO (rGO) nanosheets with larger dimensions trigger the best cell response, while the rGO nanosheets with smaller size provoke an accentuated decrease in the cytocompatibility of the resulting electrospun meshes. Then, the most auspicious nanofibers are synergistically accommodated onto the surface of 3D-rGO heterogeneous porous networks, giving rise to fibrous-porous combinatorial architectures suitable for enhancing adhesion and differentiation of neural cells. By varying the chemical composition of the nanofibers, it is possible to adapt their performance as physical crosslinkers for the rGO sheets, leading to the modulation of both pore size and structural/mechanical integrity of the scaffold. Importantly, the biocompatibility of the resultant fibrous-porous systems is not compromised after 14 days of cell culture, including standard differentiation patterns of neural progenitor cells. Overall, in light of these in vitro results, the reported scaffolding approach presents not only an indisputable capacity to support highly viable and interconnected neural circuits but also the potential to unlock novel strategies for neural tissue engineering applications.
A significant number of therapeutics derived from natural polymers and plants have been developed to replace or to be used in conjunction with existing dressing products. The use of the therapeutic ...properties of aloe vera could be very useful in the creation of active wound dressing materials. The present work was undertaken to examine issues concerning structural features, topography, enzymatic degradation behavior, antibacterial activity and cellular response of chitosan/aloe vera-based membranes. The chitosan/aloe vera-based membranes that were developed displayed satisfactory degradation, roughness, wettability and mechanical properties. A higher antibacterial potency was displayed by the blended membranes. Moreover, in vitro assays demonstrated that these blended membranes have good cell compatibility with primary human dermal fibroblasts. The chitosan/aloe vera-based membranes might be promising wound dressing materials.
This paper reviews recent advances in graphene-based biosensors development in order to obtain smaller and more portable devices with better performance for earlier cancer detection. In fact, the ...potential of Graphene for sensitive detection and chemical/biological free-label applications results from its exceptional physicochemical properties such as high electrical and thermal conductivity, aspect-ratio, optical transparency and remarkable mechanical and chemical stability. Herein we start by providing a general overview of the types of graphene and its derivatives, briefly describing the synthesis procedure and main properties. It follows the reference to different routes to engineer the graphene surface for sensing applications with organic biomolecules and nanoparticles for the development of advanced biosensing platforms able to detect/quantify the characteristic cancer biomolecules in biological fluids or overexpressed on cancerous cells surface with elevated sensitivity, selectivity and stability. We then describe the application of graphene in optical imaging methods such as photoluminescence and Raman imaging, electrochemical sensors for enzymatic biosensing, DNA sensing, and immunosensing. The bioquantification of cancer biomarkers and cells is finally discussed, particularly electrochemical methods such as voltammetry and amperometry which are generally adopted transducing techniques for the development of graphene based sensors for biosensing due to their simplicity, high sensitivity and low-cost. To close, we discuss the major challenges that graphene based biosensors must overcome in order to reach the necessary standards for the early detection of cancer biomarkers by providing reliable information about the patient disease stage.
The potential thermal regulation effect of rigid polyurethane (RPU) foams can be enhanced by the incorporation of phase change materials (PCM). The main goal of the present work is to evaluate the ...thermal characteristics of RPU panels using two different types of PCM (a commercial one and another based on paraffin and calcium carbonate) and to quantify their potential as thermal regulators of indoor spaces.
The experimental results obtained revealed that the RPU panels incorporating PCM can lead to a thermal amplitude reduction of about 3.5–1 °C (peak maximum temperature – peak minimum temperature). Furthermore, it was demonstrated that the performance of the RPU panel with PCM was enhanced when the external and internal mean temperature were closer to the melting peak temperature of the PCM. Additionally, it was also verified that the thermal amplitude reduction due to the PCM is more significant for the RPU panel incorporating PCM.
In brief, the results showed that the efficiency of the RPU panels incorporating PCM is not exclusively dependent on the presence and quantity of PCM (equivalent in wt% in all cases) but it is also affected by the imposed temperature profile and the PCM thermal properties.
•Rigid polyurethane foams (RPU) panels incorporating phase change materials (PCM).•Commercial microencapsulated PCM versus shape stabilized CaCO3 containing-PCM.•Inclusion of PCM on RPU panels enhances the thermal regulation of indoor spaces.•Efficiency of RPU panels is not exclusively dependent on the quantity of PCM.•Thermal performance is affected by the imposed temperature and the PCM properties.
This study focuses on the ability of commercial natural bath sponges, which are made from the skeletons of marine sponges, to sorb Hg from natural waters. The main component of these bath sponges is ...spongin, which is a protein-based material, closely related to collagen, offering a plenitude of reactive sites from the great variety of amino acids in the protein chains, where the Hg ions can sorb. For a dose of 40 mg L−1 and initial concentration of 50 μg L−1 of Hg(II), marine spongin (MS) removed ~90% of Hg from 3 water matrixes (ultrapure, bottled, and seawater), corresponding to a residual concentration of ~5 μg L−1, which tends to the recommend value for drinking water of 1 μg L−1. This value was maintained even by increasing the MS dosage, suggesting the existence of a gradient concentration threshold below which the Hg sorption mechanism halts. Kinetic modelling showed that the Pseudo Second-Order equation was the best fit for all the water matrixes, which indicates that the sorption mechanism relies most probably on chemical interactions between the functional groups of spongin and the Hg ions. This material can also be regenerated in HNO3 and reused for Hg sorption, with marginal losses in efficiency, at least for 3 consecutive cycles.
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•Pure marine sponge was tested as sorbent for Hg(II) removal in real waters.•Up to 89% Hg(II) removal from seawater using 40 mg L−1 of marine sponge.•Pseudo-second order kinetic model is the best fit for the experimental data.•Marine sponge samples could be regenerated and reused up to three times.
The increasing interest on the application of ionic liquids (ILs) to a wide range of processes and products has been hampered by a lack of toxicological data, mainly in what concerns novel cations, ...such as guanidinium, phosphonium, and functionalized and non-functionalized imidazolium-based ILs. The present study reports the toxicity of five guanidinium-, six phosphonium, and six imidazolium-based ILs, towards the luminescent marine bacteria
Vibrio fischeri. These new results clearly show that guanidinium-, unlike the imidazolium- and phosphonium-based ILs, do not follow the trend of increasing toxicity with the increase in the alkyl chain length. Moreover, the introduction of oxygenated groups on the alkyl chains, such as ether and ester, leads to a decrease of the toxicity of guanidinium and also imidazolium compounds. In what respects the effect of the different cations, it is possible to recognize that the phosphonium-based ILs seem to be more toxic when compared to the analog imidazolium-based ILs (with the same anion and alkyl chains).
► Toxicological profile of ILs towards
Vibrio fischeri. ► Various ILs families guanidinium, phosphonium, and imidazolium tested. ► Two different established trends: “side chain effect” and “cut-off” effect. ► Decrease in toxicity with the oxygenation of the side chains. ► Affect of anion related with the elongation of the alkyl chains conjugated.
For a while, gold nanoparticles (AuNPs) have been recognized as potential radiosensitizers in cancer radiation therapy, mainly due to their physical properties, making them appealing for medical ...applications. Nevertheless, the performance of AuNPs as radiosensitizers still raises important questions that need further investigation. Searching for selective prostate (PCa) radiosensitizing agents, we studied the radiosensitization capability of the target-specific AuNP-BBN in cancer versus non-cancerous prostate cells, including the evaluation of dose rate effects in comparison with non-targeted counterparts (AuNP-TDOTA). PCa cells were found to exhibit increased AuNP uptake when compared to non-tumoral ones, leading to a significant loss of cellular proliferation ability and complex DNA damage, evidenced by the occurrence of multiple micronucleus per binucleated cell, in the case of PC3 cells irradiated with 2 Gy of γ-rays, after incubation with AuNP-BBN. Remarkably, the treatment of the PC3 cells with AuNP-BBN led to a much stronger influence of the dose rate on the cellular survival upon γ-photon irradiation, as well as on their genomic instability. Overall, AuNP-BBN emerged in this study as a very promising nanotool for the efficient and selective radiosensitization of human prostate cancer PC3 cells, therefore deserving further preclinical evaluation in adequate animal models for prostate cancer radiotherapy.
Nowadays, the development of sustainable high-performance functional nanomaterials is in the spotlight. In this work, we report the preparation of a new generation of flexible and high ...electroconductive nanopapers based on nanofibrillated cellulose (NFC) and copper nanowires (CuNWs). Homogeneous red brick color nanopapers (thickness 30.2–36.4 μm) were obtained by mixing different amounts of NFC aqueous suspensions and CuNWs (1, 5, 10, 20, and 50 wt %), followed by vacuum filtration and drying. scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analysis confirmed the incorporation of the different amounts of CuNWs, and their uniform and random distribution. All of the nanomaterials displayed good mechanical properties, viz., Young’s modulus = 2.62–4.72 GPa, tensile strength = 30.2–70.6 MPa, and elongation at break = 2.3–4.1% for the nanopapers with 50 and 1 wt % of CuNWs mass fraction, respectively. The electrical conductivity of these materials strongly depends on the CuNW content, attaining a value of 5.43 × 104 S·m–1 for the nanopaper with a higher mass fraction. This is one of the highest values reported so far for nanocellulose-based conductive materials. Therefore, these nanopapers can be seen as an excellent inexpensive and green alternative to the current electroconductive materials for applications in electronic devices, energy storage, or sensors.
The inability of the heart to recover from an ischemic insult leads to the formation of fibrotic scar tissue and heart failure. From the therapeutic strategies under investigation, cardiac ...regeneration holds the promise of restoring the full functionality of a damaged heart. Taking into consideration the presence of vast numbers of fibroblasts and myofibroblasts in the injured heart, direct fibroblast reprogramming into cardiomyocytes using small drug molecules is an attractive therapeutic option to replenish the lost cardiomyocytes. Here, a spermine‐acetalated dextran‐based functional nanoparticle is developed for pH‐triggered drug delivery of two poorly water soluble small molecules, CHIR99021 and SB431542, both capable of increasing the efficiency of direct reprogramming of fibroblast into cardiomyocytes. Upon functionalization with polyethylene glycol and atrial natriuretic peptide, the biocompatibility of the nanosystem is improved, and the cellular interactions with the cardiac nonmyocytes are specifically augmented. The dual delivery of the compounds is verified in vitro, and the compounds exerted concomitantly anticipate biological effects by stabilizing β‐catenin (CHIR99021) and by preventing translocation of Smad3 to the nucleus of (myo)fibroblasts (SB431542). These observations highlight the potential of this nanoparticle‐based system toward improved drug delivery and efficient direct reprogramming of fibroblasts into cardiomyocyte‐like cells, and thus, potential cardiac regeneration therapy.
Pharmacological cellular reprogramming is a highly relevant therapeutic strategy toward cardiac regeneration, and the application of nanoparticles in this emerging field is scarcely explored. Here, a dual‐loaded multifunctional and cardiac‐specific nanoparticulate system for potential application in cellular reprogramming of nonmyocytes into cardiomyocyte‐like cells is reported, promoting pH‐triggered drug delivery and modulation of signaling factors involved in cardiac reprogramming.
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