NP Content Research Articles

Uptake, translocation and health risk assessment of nonylphenol in vegetables under reclaimed water irrigation

AbstractNonylphenol (NP) is one of the typical endocrine‐disrupting chemicals (EDCs), which can be harmful at very low concentrations. Municipal sewage and reclaimed water are its two main sources. EDCs can enter into the soil with reclaimed water irrigation and accumulate in plants, causing environmental and human health risks. The occurrence and migration of NP in soil‐crop systems were studied by pot experiments of lettuce and eggplants simulating long‐term irrigation with reclaimed water. The health risks were also evaluated. The experiments set treatments with different initial soil NP concentrations (0.28–6.42 mg/kg) and soil moisture (60%–90% field water capacity [FC]). After harvest, the NP in edible parts of lettuce and eggplants were 35.80–54.30 and 15.45–23.38 μg/kg, respectively. The residual amounts of NP in the soil‐lettuce system and soil‐eggplant system were limited with the residual rates of 0.9%–24.4% and 0.3%–14.5%, respectively. The results showed that the lettuce and eggplant tissues had the highest bioconcentration factors (BCFs) in 75% FC and the translocation factors (TFs) tended to decrease with the initial soil NP contents increased. The noncancer hazard quotients (HQ) for adults and children exposed to NP had the order of 10−5, which showed little health risk for reclaimed water irrigation.

Effect of fertility levels and stress mitigating chemicals on nutrient content, uptake, intercropping advantage and competition effect in cowpea-baby corn intercropping

The primary goal of this study was to analyze how various row ratios of intercrops, in conjunction with different fertilizer levels with spray of two stress mitigating chemical, affect nutrient content, land productivity, and economic viability during Summer season. Furthermore, we aimed to explore the competitive dynamics within legume/cereal intercropping systems. Hence, A field experiment at Agriculture University, Kota, during the summers of 2019 and 2020, investigated different cowpea + baby corn intercropping system's intercropping indices, nutrient dynamics, uptake, and post-harvest soil nutrient balance under varying recommended fertilizer levels and foliar spray of stress mitigating chemicals. Using a split-split plot design replicated four times, the experiment involved thirty treatment combinations, including five intercropping techniques viz. Sole cowpea, sole baby corn, cowpea + baby corn 2:1, cowpea + baby corn 3:1, cowpea + baby corn 4:1 in the main plot, three fertility levels viz. 100 %, 125 % and 150 % recommended dose of fertilizer (RDF) in subplots, and two stress mitigation chemicals; CaCl2 0.5 % and KNO3 1% in sub-subplots. The findings revealed notable trends, including nitrogen (N) and (P) content in cowpea seeds and straw, baby corn cobs and fodder, as well as enhanced land-equivalent ratio (LER) and monetary advantage index (MAI) within the cowpea + baby corn 2:1 row ratio. However, despite these advantages, total N and P uptake were markedly higher in sole crops. Notably, sole cowpea demonstrated the highest actual N and P balance and lowest was under sole baby corn. Among the fertility levels, the 150 % RDF level exhibited the most favorable outcomes across various parameters, including LER, MAI, NP content, and uptake in both crops. Additionally, higher fertility levels correlated with increased apparent and actual soil nutrient balances. While, among stress mitigation chemicals, CaCl2 0.5 % resulted in significantly heightened N and P uptake. Hence, to optimize intercropping dynamics and maintain soil nutrient balance, it is advisable to intensify cowpea cultivation along with baby corn in a 2:1 row ratio, utilizing 150 % RDF is beneficial. Additionally, alleviating higher temperature stress during the summer season can be achieved by applying a 0.5 % solution CaCl2 through spraying at the flowering and pod development stages of cowpea.

Bio-inspired stretchable and self-healable nanocomposite gelatin hydrogel with low silica nanoparticle content and brilliant angle/strain-independent structural colors

Stretchable and self-healable structural-colored nanocomposite gelatin hydrogel with photonic structure of random dense/loose regions of non-close-packed silica nanoparticles (SiO2 NPs) is developed via convenient and scalable polymer-mediated assembly. The formation of the special photonic structure with overall low SiO2 NP content is characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The small-angle X-ray scattering test indicates the existence of short-range order, which is consistent with the TEM and SEM results. The dense photonic structure consisting of SiO2 NP chains and domains, and the loose structure consisting of abundant solitary SiO2 NPs, accounts for pronounced and uniform structural colors via combined effects of coherent scattering of light by dense structure, and Mie scattering of solitary NPs. These structural colors are independent of viewing angles and large mechanical strains. The dynamic physical and chemical bonding of the gelatin hydrogel network matrix enables self-healing functions and good deformability. Moreover, salt treatment of the structural-colored gelatin hydrogel networks enhances physical crosslinking and the mechanical strength of the hydrogel. The resilient, flexible and self-healable structural-colored nanocomposite hydrogel with low SiO2 NP content has great potential in wearable photonics, cosmetics, and various other color-related fields. This work also sheds light on enhancing non-iridescent structural colors through advanced photonic design.

Wound Dressing Based on Silver Nanoparticle Embedded Wool Keratin Electrospun Nanofibers Deposited on Cotton Fabric: Preparation, Characterization, Antimicrobial Activity, and Cytocompatibility.

Wool keratin (WK) protein is attractive for wound dressing and biomedical applications due to its excellent biodegradability, cytocompatibility, and wound-healing properties. In this work, WK-based wound dressings were prepared by depositing WK/poly(vinyl alcohol) (PVA) and silver nanoparticle (Ag NP)-embedded WK/PVA composite nanofibrous membranes on cotton fabrics by electrospinning. Ag NPs were biosynthesized by reduction and stabilization with sodium alginate. The formed Ag NPs were characterized by ultraviolet-visible and Fourier transform infrared (FTIR) spectroscopy, and their size was determined by transmission electron microscopy and image analysis. The formed Ag NPs were spherical and had an average diameter of 9.95 nm. The produced Ag NP-embedded WK/PVA composite nanofiber-deposited cotton fabric surface was characterized by FTIR and dynamic contact angle measurements, and the nanofiber morphologies were characterized by scanning electron microscopy. The average diameter of the nanofibers formed by 0.1% Ag NP-embedded WK/PVA solution was 146.7 nm. The antibacterial activity of the surface of cotton fabrics coated with electrospun composite nanofibers was evaluated against the two most common wound-causing pathogens, Staphylococcus aureus and Pseudomonas aeruginosa. The cotton fabric coated with 0.1% Ag NP-embedded WK/PVA nanofibers showed very good antibacterial activity against both pathogens, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay results showed good cytocompatibility against L-929 mouse fibroblast cells. However, the increase in Ag NP content in the nanofibers to 0.2% negatively affected the cell viability due to the high release rate of Ag ions. The results achieved show that the developed wound dressing has good potential for wound healing applications.

Identification and quantification of trace metal(loid)s in water-extractable road dust nanoparticles using SP-ICP-MS

Resuspension of road dust is a major source of airborne particulate matter (PM) in urban environments. Inhalation of ultrafine particles (UFP; < 0.1 μm) represents a health concern due to their ability to reach the alveoli and be translocated into the blood stream. It is therefore important to characterize chemical properties of UFPs associated with vehicle emissions. We investigated the capability of Single-Particle ICP-MS (SP-ICP-MS) to quantify key metal(loid)s in nanoparticles (NPs; < 0.1 μm) isolated from road dust collected in Toronto, Canada. Water extraction was performed to separate the <1-μm fraction from two different road dust samples (local road vs. arterial road) and a multi-element SP-ICP-MS analysis was then conducted on the samples' supernatants. Based on the particle number concentrations obtained for both supernatants, the metal(loid)-containing NPs could be grouped in the following categories: high (Cu and Zn, > 1.3 × 1011 particles/L), medium (V, Cr, Ba, Pb, Sb, Ce, La), low (As, Co, Ni, < 4.6 × 109 particles/L). The limit of detection for particle number concentration was below 5.5 × 106 particles/L for most elements, except for Cu, Co, Ni, Cr, and V (between 0.9 and 7.7 × 107 particles/L). The results demonstrate that road dust contains a wide range of readily mobilizable metal(loid)-bearing NPs and that NP numbers may vary as a function of road type. These findings have important implications for human health risk assessments in urban areas. Further research is needed, however, to comprehensively assess the NP content of road dust as influenced by various factors, including traffic volume and speed, fleet composition, and street sweeping frequency. The described method can quickly characterize multiple isotopes per sample in complex matrices, and offers the advantage of rapid sample scanning for the identification of NPs containing potentially toxic transition metal(loid)s at a low detection limit.

Synthesis, Characterization, and Ecotoxicology Assessment of Zinc Oxide Nanoparticles by In Vivo Models

The widespread use of zinc oxide nanoparticles (ZnO NPs) in multiple applications has increased the importance of safety considerations. ZnO NPs were synthesized, characterized, and evaluated for toxicity in Artemia salina and zebrafish (Danio rerio). NPs were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and ultraviolet-visible (UV-Vis) spectroscopy. The hydrodynamic size and stability of the ZnO NP surface were examined using a Zetasizer. Characterization techniques confirmed the ZnO wurtzite structure with a particle size of 32.2 ± 5.2 nm. Synthesized ZnO NPs were evaluated for acute toxicity in Artemia salina using the Probit and Reed and Muench methods to assess for lethal concentration at 50% (LC50). The LC50 was 86.95 ± 0.21 μg/mL in Artemia salina. Physical malformations were observed after 96 h at 50 μg/mL of exposure. The total protein and cytochrome P450 contents were determined. Further analysis was performed to assess the bioaccumulation capacity of zebrafish (Danio rerio) using ICP-OES. ZnO NP content in adult zebrafish was greater in the gastrointestinal tract than in the other tissues under study. The present analysis of ZnO NPs supports the use of Artemia salina and adult zebrafish as relevant models for assessing toxicity and bioaccumulation while considering absorption quantities.

Development of a novel NiCu nanoparticle-loaded polysaccharide-based hydrogel for 3D printing of customizable dressings with promising cytotoxicity against melanoma cells.

Polysaccharide hydrogels and metal alloy nanoparticles have already found use in a range of biomedical applications. Nickel-copper nanoparticles (NiCu NPs) are particularly promising due to their tunable properties, such as ferromagnetism, biocompatibility, and antimicrobial activity. At the same time, polysaccharide hydrogels made of polymer mixtures such as alginate and methylcellulose with incorporated metal alloy nanoparticles are reported in the scientific literature. In view of this, in this work, NiCu NPs are combined with polysaccharide hydrogels and 3D printed to construct geometrically customizable dressings with tailorable properties for melanoma treatment. This novel combination exploits the intrinsic magnetic properties of NiCu NPs and the same time builds on their less known properties to improve the mechanic stability of 3D printed materials, both contributing to a previously not reported application as potent cytotoxic dressing against melanoma cells. The dressings were evaluated in terms of their physico-chemical characteristics, and their potential application, namely melanoma cell cytotoxicity. While all dressings exhibited similar degradation profiles regardless of composition, the addition of NiCu NPs had an effect on the hydrophilicity, swelling rates, and topographical properties of the dressings. Compression results showed that the presence of NPs increased the stiffness of the dressings, while the ultimate tensile strength was highest at 0.31MPa for the dressings with 0.5wt% NPs. We show that although the base formulation of the dressings is biocompatible with skin-derived cells, dressings loaded with NPs exhibit promising antimelanoma activity. Extracts obtained from dressings containing 0.5wt% NPs reduced melanoma cell viability to 61%±11% and 40%±2% after 24h and 72h of soaking, respectively. Furthermore, extracts of dressings with 1wt% NPs reduced melanoma cell viability to less than 15% within the first 24h. By adjusting the NP content, the mechanical properties, surface roughness, and wettability can be tuned so that the dressings can be functionally customized. In addition, by using 3D printing as a fabrication process, the shape and composition of the dressings can be tailored to the patient's needs. The dressings also remained intact after soaking in simulated physiological solution for 14 days, indicating their suitability for long-term topical application.

Sustainable Collagen Composites with Graphene Oxide for Bending Resistive Sensing.

This work reports on the development of collagen films with graphene oxide nanoparticles (GO NPs), aiming toward the development of a new generation of functional sustainable sensors. For this purpose, different GO NP contents up to 3 wt % were incorporated into a collagen matrix, and morphological, thermal, mechanical and electrical properties were evaluated. Independently of the GO NP content, all films display an increase in thermal stability as a result of the increase in the structural order of collagen, as revealed by XRD analysis. Further, the inclusion of GO NPs into collagen promotes an increase in the intensity of oxygen characteristic absorption bands in FTIR spectra, due to the abundant oxygen-containing functional groups, which lead to an increase in the hydrophilic character of the surface. GO NPs also influence the mechanical properties of the composites, increasing the tensile strength from 33.2 ± 2.4 MPa (collagen) to 44.1 ± 1.0 MPa (collagen with 3 wt % GO NPs). Finally, the electrical conductivity also increases slightly with GO NP content, allowing the development of resistive bending sensors.

Antioxidant properties of zinc oxide nanoparticles synthesised from Syzygium cumini seed extract

The jamun fruit, Syzygium cumini, is known for its significant antioxidant and antigenotoxic characteristics in addition to its antidiabetic effects. Although numerous plant parts are utilized in herbal preparations, the chemical makeup of the fruit and seed is little understood. The high phenolic content of the seed was recently reported. In this study, zinc oxide nanoparticles (ZnO NPs) from Syzygium cumini are synthesized, characterized and evaluated for their antioxidant characteristics (SC). SC seed extract was used to make ZnO NPs which were then studied using X-ray diffraction (XRD), Transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and Ultraviolet-visible spectroscopy. Several doses of nanoparticles were used in antioxidant assays such as the reducing power assay, the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and the hydrogen peroxide assay. It was discovered that the antioxidant activity increased along with the NP content.

Synthesis and characterization of highly efficient Te-doped Mn3O4 and s-g-C3N4 /Te- Mn3O4 nanocomposites as an excellent antimicrobial and photocatalytic agent

This work aims to synthesize manganese oxide nanoparticles (Mn3O4NPs) using a co-precipitation method and analyzed them through XRD, SEM and FT-IR. The XRD analysis confirmed the tetragonal hausmanite structure of the Mn3O4 NPs, while SEM revealed an average particle size of 9–20 nm. Kinetic studies demonstrated the efficient photooxidation of methylene blue with first-order kinetics under UV or visible light. Degradation efficiencies varied between 82% and 93% depending on the light source. Furthermore, we used the zone inhibition approach to assess the antibacterial potency of various Mn3O4 NP contents alongside human pathogenic bacteria, namely Escherichia coli and Staphylococcus aureus. The results of the qualitative antibacterial tests revealed that E. coli, a Gram-negative bacterium, is more sensitive to Mn3O4 NPs than are Gram-positive bacteria, with a maximum zone diameter of 28 mm (S. aureus). Alternatively, it was determined that S-g-C3N4/Te-Mn2O3 had the maximum antifungal activity against Alternaria solani at 28.9 mm and against. Colletotrichum gloeosporioides at 47.3 mm.

Comparison of Zinc Oxide Nanoparticle Integration into Non-Woven Fabrics Using Different Functionalisation Methods for Prospective Application as Active Facemasks.

The development of advanced facemasks stands out as a paramount priority in enhancing healthcare preparedness. In this work, different polypropylene non-woven fabrics (NWF) were characterised regarding their structural, physicochemical and comfort-related properties. The selected NWF for the intermediate layer was functionalised with zinc oxide nanoparticles (ZnO NPs) 0.3 and 1.2wt% using three different methods: electrospinning, dip-pad-dry and exhaustion. After the confirmation of ZnO NP content and distribution within the textile fibres by morphological and chemical analysis, the samples were evaluated regarding their antimicrobial properties. The functionalised fabrics obtained via dip-pad-dry unveiled the most promising data, with 0.017 ± 0.013wt% ZnO NPs being mostly located at the fibre's surface and capable of total eradication of Staphylococcus aureus and Escherichia coli colonies within the tested 24 h (ISO 22196 standard), as well as significantly contributing (**** p < 0.0001) to the growth inhibition of the bacteriophage MS2, a surrogate of the SARS-CoV-2 virus (ISO 18184 standard). A three-layered structure was assembled and thermoformed to obtain facemasks combining the previously chosen NWF, and its resulting antimicrobial capacity, filtration efficiency and breathability (NP EN ISO 149) were assessed. The developed three-layered and multiscaled fibrous structures with antimicrobial capacities hold immense potential as active individual protection facemasks.

Impact of Foliar Boron and Fertilizer Management Systems on Growth, Yield and Quality of Brinjal

A field experiment was conducted during the rainy season of 2017–18 at Horticulture Farm, S.K.N. Agriculture University, Jobner, Jaipur, Rajasthan to study the role of foliar spray of boron on the growth, yield, and quality of Brinjal (Solanum melongena L.) The study was laid with 18 treatments (TThree replicates of six treatments) viz., INM levels (control, 100% inorganic NPK, 75% inorganic NPK +25%VC (vermicompost), 50% inorganic NPK +50%VC, 25% inorganic NPK +75% VC, and 100%VC and boron levels (control, 100 ppm, and 200 ppm). It was observed that there was a significant (P &lt; 0.05) increase in the plant height and plant spread at 30, 60, and 90 DAT on the application of 75% inorganic NPK +25%VC on the brinjal crop, while the application of inorganic 50% NPK +50%VC significantly (P &lt; 0.05) increased chlorophyll content (mg.g-1), fruit length (cm), fruit weight (g), fruit yield ha-1 (q), Nitrogen and Phosphorus content in fruit (%), as compared to control but statistically at par with 25% inorganic NPK +75%VC. The application of boron (200ppm) significantly (P &lt; 0.05) increased the plant height and plant spread at 30, 60, and 90 DAT(cm), chlorophyll content (mg/g), fruit length (cm), fruit weight (g), fruit yield hectare-1(q), NP content in fruit (%), as compared to control and boron (100 ppm).

Assessing the Antifungal Activity of a Soft Denture Liner Loaded with Titanium Oxide Nanoparticles (TiO2 NPs)

Soft denture lining materials are susceptible to be colonized by different microorganisms, especially by Candida albicans (C. albicans), causing denture-induced stomatitis. This study was designed to evaluate the effectiveness of incorporating titanium dioxide nanoparticles (TiO2 NPs) into a soft denture liner towards reducing microbial activity. A total of 40 PEMA-TiO2 nanocomposites samples were fabricated by adding 0.0 wt.% (control), 1.0 wt.%, 1.5 wt.%, and 2 wt.% TiO2 NPs to a heat cured soft denture lining material (polyethyl methacrylate, PEMA). The prepared samples were divided into four groups (n = 10) according to the content of TiO2 NPs. The uniformity of TiO2 NPS distribution within the denture liner matrix was assessed using a Scanning Electron Microscope (SEM). The viable count of C. albicans was evaluated to test the antifungal resistance of the developed composite. The SEM images showed fairly homogeneous dispersion, with patches of TiO2 NPs agglomeration within the PEMA matrix and an increasing concentration of NPs with higher NP content. The particle map and EDX analysis confirmed the evidence of the TiO2 NPs. The mean viable count results for the control (0.0 wt.%) and 1.0 wt.%, 1.5 wt.%, and 2 wt.% TiO2 groups were 139.80, 12.00, 6.20, and 1.00, respectively, with a significant difference from the control group (p < 0.05). The antifungal activity also increased with the increase in the concentration of TiO2 NPs. The addition of TiO2 NPs into a heat-cured soft denture liner provided antifungal activity as evidenced by the reduced colonization of C. albicans. The antimicrobial activity of the liner material increased with the increased concentration of TiO2 NPS.

Nucleus pulposus cell-derived efficient microcarrier for intervertebral disc tissue engineering

Adipose-derived stem cells (ADSCs) show great potential for the treatment of intervertebral disc (IVD) degeneration. An ideal carrier is necessary to transplant ADSCs into degenerated IVDs without influencing cell function. Nucleus pulposus cells (NPCs) can synthesize and deposit chondroitin sulfate and type II collagen which are NP-specific extracellular matrix (ECM) and can also regulate the NP-specific differentiation of stem cells. Bioscaffolds fabricated based on the ECM synthesis functions of NPCs have possible roles in cell transplantation and differentiation induction, but it has not been studied. In this study, we first aggregated NPCs into pellets, and then, NPC-derived efficient microcarriers (NPCMs) were fabricated by pellet cultivation under specific conditions and optimized decellularization. Thirdly, we evaluated the microstructure, biochemical composition, biostability and cytotoxicity of the NPCMs. Finally, we investigated the NP-specific differentiation of ADSCs induced by the NPCMs in vitro and NP regeneration induced by the ADSC-loaded NPCMs in a rabbit model. The results indicated that the injectable NPCMs retained maximal ECM and minimal cell nucleic acid after optimized decellularization and had good biostability and no cytotoxicity. The NPCMs also promoted the NP-specific differentiation of ADSCs in vitro. In addition, the results of MRI, x-ray, and the structure and ECM content of NP showed that the ADSCs-loaded NPCMs can partly restored the degenerated NP in vivo. Our injectable NPCMs regenerated the degenerated NP and provide a simplified and efficient strategy for treating IVD degeneration.

Preparation of functionalZnOnanoparticles and their application asUVphotosensitizer and reinforcing agent for waterborne polyurethane acrylate composite coating

AbstractFunctional inorganic ZnO nanoparticles (ZnO NPs) have been designed and prepared, used as UV photosensitizers and reinforcing agents applied to waterborne polyurethane acrylate (WPUA) composite coating. The ZnO NPs are modified by the silane coupling agent, and the WPUA@ZnO NP composite coatings photoinitiated with different ZnO NP contents are prepared, their structure and properties are characterized by FTIR, XRD, SEM, BET, TG, and pencil hardness tester. The UV absorption of the inorganic photosensitizer ZnO NPs and the organic photosensitizer 1‐hydroxycyclohexyl phenone (184) in the composite coating is tested and analyzed separately by DRS UV‐3600 spectrophotometer. Three fabric‐based materials (cotton, PET, and PP) are dipped into the WPUA@184 composite emulsions and WPUA@ZnO NP composite emulsions, and their mechanical properties, water absorption and water contact angle (WCA) are tested. The results show that the absorbance of the WPUA@ZnO NP composite coating is 40.28% higher than that of the WPUA@184 composite coating. Compared with the PP‐WPUA@184 coatings, the stress of the PP‐WPUA@ZnO NP coatings increases by 41.19% and the strain increases by 34.39%. The water absorption of the cotton and PET coatings decreases under the three conditions. Their hydrophilicity and hydrophobicity are changed, and the fabric‐based coatings can be tuned for interfacial properties.

Diffusion Barrier Properties of the Intermetallic Compound Layers Formed in the Pt Nanoparticles Alloyed Sn-58Bi Solder Joints Reacted with ENIG and ENEPIG Surface Finishes

Pt-nanoparticle (NP)-alloyed Sn-58Bi solders were reacted with electroless nickel-immersion gold (ENIG) and electroless nickel-electroless palladium-immersion gold (ENEPIG) surface finishes. We investigated formation of intermetallic compounds (IMCs) and their diffusion barrier properties at reaction interfaces as functions of Pt NP content in the composite solders and duration of solid-state aging at 100 °C. At Sn-58Bi-xPt/ENIG interfaces, typical Ni3Sn4/Ni3P(P-rich layer) microstructure was formed. With the large consumption of the Ni-P layer, the Ni-P and Cu layers were intermixed and Cu atoms spread over the composite solder after 500 h of aging. By contrast, a (Pd,Ni)Sn4/thin Ni3Sn4 microstructure was observed at the Sn-58Bi-xPt/ENEPIG interfaces. The (Pd,Ni)Sn4 IMC effectively suppressed the consumption of the Ni-P layer and Ni3Sn4 growth, functioning as a good diffusion barrier. Therefore, the Sn-58Bi-xPt/ENEPIG joint survived 500 h of aging without microstructural degradation. Based on the experimental results and analysis of this study, Sn-58Bi-0.05Pt/ENEPIG is suggested as the optimum combination for future low-temperature soldering systems.

Short Depuration of Oysters Intended for Human Consumption Is Effective at Reducing Exposure to Nanoplastics.

Nanoplastics (NPs; <1 μm) have greater availability to marine organisms than microplastics (1-5000 μm). Understanding NP uptake and depuration in marine organisms intended for human consumption is imperative for food safety, but until now it has been limited due to analytical constraints. Oysters (Crassostrea gigas) were exposed to polystyrene NPs doped with palladium (Pd), allowing the measurements of their uptake into tissues by inductively coupled plasma mass spectrometry (ICP-MS) combined with electron microscopy. Oysters were exposed for 6 days (d) to "Smooth" or "Raspberry" NPs, followed by 30 d of depuration with the aim of assessing the NP concentration in C. gigas following exposure, inferring the accumulation and elimination rates, and understanding the clearance of Pd NPs during the depuration period. After 6 d, the most significant accumulation was found in the digestive gland (106.6 and 135.3 μg g-1 dw, for Smooth and Raspberry NPs, respectively) and showed the most evident depuration (elimination rate constant KSmooth = 2 d-1 and KRaspberry = 0.2 d-1). Almost complete depuration of the Raspberry NPs occurred after 30 d. While a post-harvesting depuration period of 24-48 h for oysters could potentially reduce the NP content by 75%, more research to validate these findings, including depuration studies of oysters from the field, is required to inform practices to reduce human exposure through consumption.

Catalytic degradation of methyl orange using beta cyclodextrin modified polyvinylidene fluoride mixed matrix membranes imbedded with in‐situ generated palladium nanoparticles

AbstractAzo dyes effluent can cause severe and chronic effects to living organisms since they are toxic, carcinogenic, and mutagenic. They color water, reduce dissolved oxygen, block light penetration, decrease the rate of photosynthesis and adversely affect the whole aquatic biota. Catalysis is one of the methods used in degrading azo dyes to less harmful species. Catalytic palladium nanoparticles (Pd NPs) are effective in the degradation of azo dyes owing to their large surface area and unique electronic properties. However, they are costly, unstable and easily aggregate; hence, a substrate is necessary to enhance their stability, reusability, durability, catalytic efficiency, and cost effectiveness. Herein, Pd NPs were in‐situ synthesized and immobilized in beta cyclodextrin (β‐CD) modified polyvinylidene‐fluoride (PVDF) membranes. The fabricated membranes were characterized using different techniques. Pd NPs slightly improved the properties and performance of the membranes. A complete catalytic degradation of methyl orange azo dye was carried out within 20 min in the presence of sodium borohydride and the increase in Pd NP content increased the rate of degradation. The membranes were recycled and reused five times with no considerable loss of catalytic performance. Therefore, PVDF/β‐CD‐Pd membranes proved to be self‐cleaning, reusable, and efficient in removal of methyl orange from water.

Enhanced Cd2+ adsorption and toxicity for microbial biofilms in the presence of TiO2 nanoparticles

Titanium dioxide nanoparticles (TiO2 NPs) easily combine with other pollutants such as heavy metals because of their excellent physiochemical properties. However, how such an interaction may affect the binding behavior of metals onto biofilms remains largely unclear. This study, examined the effects of TiO2 NPs on Cd2+ accumulation and toxicity for natural periphytic biofilms were examined. The adsorption kinetics showed that adding 0.1 and 1 mg/L TiO2–NPs increased the Cd2+ adsorption of biofilms at equilibrium by 23.5% and 35.8%, respectively. However, adding 10 mg/L TiO2 NPs increased the Cd2+ adsorption of biofilms at equilibrium by only 1.9%. The adsorption isotherms indicate that the presence of TiO2 NPs considerably increased the Cd2+ adsorption capacity of the biofilms; however, this effect became less prominent at high TiO2 NP concentrations. The optimum pH for Cd2+ adsorption increased with increasing Cd2+ and TiO2 NP contents. At low concentrations, the coexistence of Cd2+ and TiO2 NPs may facilitate their respective accumulation by stimulating the secretion of extracellular polymeric substances and enhancing the microbial activity of the biofilm. The presence of TiO2 NPs increases the surface binding energy between Cd2+ and functional groups such as carboxyl groups, enhancing the Cd2+ accumulation on the biofilm.

Poly(lactic-co-glycolide) based biodegradable electrically and magnetically active microenvironments for tissue regeneration applications

Polymer scaffolds are playing an increasing role in tissue engineering (TE), although there is still a need to improve their biomimicry of cellular microenvironments, by having smart scaffolds with an active response, which can improve tissue regeneration.This work reports on the novel combination of poly(lactic-co-glycolide) (PLGA) with the ionic liquid (IL) choline bis(trifluoromethylsulfonyl)imide ([Chol][TFSI]) or with iron oxide nanoparticles (Fe3O4, NP) in order to achieve biodegradable scaffolds with electroactive and magnetoactive response, respectively.The composites were processed into fiber and film morphologies. PLGA + IL fibers present diameters between 1.92 and 3.26 µm, decreased mechanical stiffness and elongation at yield with respect to the pristine polymer, and some fiber concentrations are not biocompatible. PLGA + IL films present a mean roughness 6.58 nm, increased mechanical stiffness with respect to the pristine polymer and decreased elongation at yield. The inclusion of IL increased the electrical conductivity of the polymer by 4 orders or magnitude. The diameter of PLGA + Fe3O4 fibers ranged from 0.62 to 1.36 µm, show an effective magnetic NP content yield between 52 and 78%, decreased stiffness and increased elongation at yield. PLGA + Fe3O4 films show a mean roughness of 5.07 nm, effective NP content yield between 77 and 97%, increased stiffness and elongation at yield.Cytotoxicity assays indicate that the PLGA + Fe3O4 materials are suitable for biomedical applications, independently of the filler content and morphology, whereas the IL containing samples are non-cytotoxic only in film morphology up to 5% wt. IL content.Finally, it is demonstrated that dynamic magneto mechanical stimulation of the PLGA + Fe3O4 samples allows the acceleration of the degradation rate of the samples.