High Nanoparticle Concentrations Research Articles

Synthesis and Characterization of 5-Fluoroacil Loaded Calcium Carbonate Nanoparticles for Targeted Cancer Therapy

Chemotherapy is often limited by its systemic toxicity and lack of specificity, necessitating the development of targeted drug delivery systems that can enhance therapeutic efficacy while minimizing adverse effects. Addressing this, our study aimed to synthesize and characterize 5-Fluorouracil loaded calcium carbonate nanoparticles derived from cockle shells. The research aimed at increasing site-specific drug release and reducing cytotoxicity. The nanoparticles were prepared using a simple co-precipitation method, ensuring eco-friendliness and cost-effectiveness. The encapsulation of 5-FU was confirmed by transmission electron microscopy (TEM), which revealed an increase in nanoparticle size from 19.2 ± 2.284 nm for the unloaded ones to 34.8 ± 4.066 nm for the 5-FU-loaded CaCO3 NPs. In vitro release studies demonstrated a pH-sensitive release profile, with more rapid drug release at pH 4.8 compared to pH 7.3. Biocompatibility assays on the HS-27 human skin fibroblast cell line indicated high cell viability, with over 90% maintained even at high nanoparticle concentrations (1000 µg/mL). In addition, cytotoxicity assays on the SW480 (primary colon cancer) and SW620 (metastatic colon cancer) cell lines showed a dose-dependent decrease in cell viability and demonstrated a more controlled and sustained release compared to free 5-FU, resulting in higher cell viability at all time points and concentra-tions. The 5-FU-loaded CaCO3 NPs significantly reduced the immediate cytotoxic effects observed with free 5-FU while effectively targeting cancer cells. These findings suggest that the 5-FU-CaCO3 NPs offer a promising alternative to conventional chemotherapy, providing targeted drug delivery with the potential for reduced systemic toxicity and enhanced therapeutic efficacy.

Thermal and Flow Characteristics of Alumina Nanofluids in Microfluidic Systems: A Low-Concentration Study

Microfluidic technologies and nanofluids represent a synergistic combination with significant potential for enhancing heat transfer and thermal management applications. This study investigates the thermal and flow characteristics of a 0.001 wt.% alumina (Al₂O₃)-water nanofluid within a custom-designed serpentine microfluidic channel. The nanofluid was prepared and characterized for its thermal conductivity, viscosity, specific heat, and density. Experimental microfluidic studies, supplemented by numerical simulations, were conducted to evaluate the fluid's behavior under controlled conditions. Results indicated a slight increase in thermal conductivity for the Al₂O₃ nanofluid compared to pure water, with increments ranging from 0.16% at 20°C to 0.30% at 80°C, attributed to enhanced Brownian motion of the nanoparticles. Viscosity measurements revealed marginal increases, suggesting minimal impact on fluid flow dynamics. The microfluidic experiments demonstrated a consistent pressure gradient and laminar flow regime, essential for precise control and efficient thermal management. Temperature contours showed effective heat dissipation, with a steady thermal gradient from the inlet to the outlet. The study concludes that low-concentration Al₂O₃ nanofluids can enhance thermal performance in microfluidic systems without significantly affecting flow characteristics, making them suitable for applications requiring efficient heat dissipation, such as electronic cooling and chemical reactions. These findings provide a foundation for future research into higher nanoparticle concentrations and different base fluids, aimed at optimizing the thermal and flow properties of nanofluids in microfluidic environments. The integration of nanofluids with microfluidic technologies holds promise for advancing the performance and reliability of next-generation thermal management systems.

High Concentrations of Nanoparticles From Isoprene Nitrates Predicted in Convective Outflow Over the Amazon

AbstractThe biogenic volatile organic compounds isoprene and α‐pinene are abundant over the Amazon and can be efficiently transported to the upper troposphere by deep convective clouds (DCC). We simulate their transport and chemistry following DCC updrafts and upper tropospheric outflow using a multi‐phase chemistry model with aerosol microphysics constrained by recent field measurements. In the lightning‐ and NO‐rich early morning outflow, organonitrates dominate the predicted ultra‐ and extremely‐low‐volatility organic compounds (ULVOCs+) derived from isoprene and α‐pinene. Nucleation of particles by α‐pinene‐derived ULVOCs+ alone, with an associated formation rate of 1.7 nm molecular clusters of 0.0006 s−1 cm−3 and resulting maximum particle number concentration of 19 cm−3, is not sufficient to explain ultrafine aerosol abundances observed in Amazonian DCC outflow. When isoprene‐derived ULVOCs+ are allowed to contribute to nucleation, the new particle formation rate increases by six orders of magnitude, and the predicted number concentrations reach 104 cm−3, consistent with observations.

Nanoconfinement-induced shift in photooxidative degradation pathway of polystyrene.

Polymer nanocomposites with high concentrations of nanoparticles (NPs) possess exceptional mechanical, transport, and thermal properties. To enable their widespread use in structural applications and functional coatings, it is crucial to understand how nanoconfinement and the polymer-NP interface influence polymer degradation under various environmental conditions, including prolonged UV exposure. In this study, we investigate the photooxidative degradation of polystyrene (PS)-confined in the interstices of SiO2 NP films. These nanocomposite films are prepared by the capillary rise infiltration (CaRI) of PS into interstices of SiO2 NP packings, and subsequently subjected to UV irradiation. Our investigation reveals that PS degradation progresses uniformly across the thickness, with degradation initiating from the center of the NP interstitial pores and extending towards the NP surface. We rationalize this degradation mechanism based on the disparity in the surface energies of PS and the NP surface, as well as slow oxygen diffusion through confined PS. We also demonstrate that packing smaller NPs at a given thickness or thicker packing of a specific NP size facilitates photooxidative degradation, highlighting the critical role of the number of interstitial pores in influencing degradation processes.

Evaluation of the electrical behavior of tungsten trioxide and cobalt oxide nanoparticles filled poly (ɛ-caprolactone) composite for optoelectronic devices

This study obtains the electrical characterization of nanocomposites comprising Poly(ɛ-caprolactone) (PCL), tungsten trioxide (WO3), and cobalt oxide (Co3O4) nanoparticles. The fabrication of these nanocomposites through a casting method aimed to enhance their electrical conductivity and dielectric properties. The AC conductivity (σac) was analyzed across varying frequencies, revealing a notable increase with the addition of Co3O4 nanoparticles, particularly up to the high content of Co3O4 nanoparticles. This enhancement is attributed to the formation of ion transport pathways and the increased amorphous regions within the PCL matrix. Dielectric properties were assessed through ε′ and ε'') measurements, which exhibited a decrease with increasing frequency, indicating the dielectric relaxation processes of the composite. The complex electric modulus analysis demonstrated a significant relationship between the real and imaginary components, suggesting potential ionic conductivity in the nanocomposites. Additionally, the Argand plot revealed a depressed semicircle, indicating a distribution of relaxation times, which further confirmed the enhancement of conductivity with raising laser ablation time. Overall, the results indicate that the addition of WO3 and Co3O4 nanoparticles significantly improves the electrical properties of PCL, making these nanocomposites suitable for various electrical applications.

Impact of Biosynthesized CeO2 Nanoparticle Concentration on the Tribological, Rheological, and Thermal Performance of Lubricating Oil

This study presents an approach to enhance the performance of lubricating oils through the environmentally friendly synthesis of cerium oxide (CeO2) nanoparticles using Moringa oleifera leaf extract. These biosynthesized nanoparticles were thoroughly characterized for their structural and thermal stability by utilizing X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The CeO2 nanolubricants, prepared at various concentrations, displayed significant improvements in viscosity, stability, and thermal conductivity. Specifically, the 0.15 wt% concentration achieved the best performance, reducing viscosity to 9.79 pascal-second (Pa·s) at 80 °C while exhibiting excellent dispersion and minimal sedimentation over time. The thermal conductivity tests revealed a notable 43% increase in heat transfer efficiency at higher nanoparticle concentrations. Tribological tests conducted using a tribometer demonstrated significant improvements in the lubrication properties. The nanolubricant with a 0.15 wt% concentration of CeO2 nanoparticles achieved the lowest friction coefficient, showing an approximate 26% reduction compared to the base oil, along with a notable decrease in wear rate. This study demonstrates the potential of biosynthesized CeO2 nanoparticles as effective, sustainable additives in lubricating oils, providing improved thermal, rheological, and tribological properties and marking a significant step toward eco-friendly lubrication solutions.

Thermophysical and corrosion inhibitor evaluation of graphene, aluminum nitride and barium titanate nanolubricants

A newly developed kind of fluid known as nanolubricant is produced by dispersing nanometer-sized materials in base oil. The main issue with nanolubricant is particle stability, which occurs when nanoparticles aggregate due to van der Waals forces. The aim of the study is to evaluate the performance of graphene (GR), aluminium nitride (AlN), and barium titanate (BTO) nanolubricants at 0.05 and 0.1 vol % concentrations. The stability was identified by using sedimentation photograph capturing method and zeta potential analysis, while KD2 Pro Analyzer was used to measure the thermal conductivity, and the effect of corrosion inhibitor evaluation was measured according to ASTM D130-19. The nanolubricants are prepared by two-step method and undergo ultrasonication process to ensure the nanoparticles are well dispersed in base oil. The results showed that nanolubricants containing 0.05 vol % nanoparticles are more stable than 0.1 vol % nanolubricants. Nanolubricants with 0.1 vol % showed signs of instability based on low zeta potential values. This is due to the fact that the higher the concentration of nanoparticles, the closer the nanoparticles are to one another. This increased van der Waals attraction and potentially causing nanoparticle agglomeration. Improvement in thermal conductivity was obtained with high volume concentration of GR, AlN and BTO nanoparticles. All nanolubricants achieved an ASTM Standard D130 classification of 1a based on the Copper Strip Corrosion Test Standard (slight tarnish, slight colour change). As a result, it was discovered that all prepared samples are effective anticorrosion lubricating oil additives.

Are Nanostructured Lipid Carriers (NLC) better than Solid Lipid Nanoparticles (SLN) for delivering abiraterone acetate through the gastrointestinal tract?

Abiraterone acetate (AbA) is a progesterone derivative indicated for the treatment of metastatic prostate cancer. This BCS (Biopharmaceutics Classification System) Class IV molecule has an extremely poor oral bioavailability (<10 %), notably due to its very low water solubility and intestinal permeability. Among the few existing galenic strategies to improve AbA’s oral bioavailability, lipid nanoparticles such as Solid Lipid Nanoparticles (SLN) and Nanostructured Lipid Carriers (NLC) are relevant nanovectors. The objective of this study is to develop and compare SLN and NLC for oral delivery of abiraterone acetate. Both SLN and NLC are biocompatible, biodegradable and produced by high pressure homogenization (HPH), an ecological-friendly manufacturing process, organic solvent-free and easily scalable. The HPH process allowed the formation of AbA-loaded SLN and NLC with particle size lower than 160 nm and high encapsulation efficiencies. The addition of a liquid lipid significantly reduced the mean diameter of the nanoparticles, reflecting the greater benefit of the NLC formulation compared to SLN. Both SLN and NLC formulations offered an important protection of AbA in intestinal media, with a better stability for NLC. When encapsulated in SLN or NLC, the AbA is strongly retained by the nanoparticles, whatever the dissolution medium, which means that both formulas are able to protect and retain the drug in the intestinal tract, right up to its delivery to the enterocytes surface. High concentrations of nanoparticles were administered without cytotoxicity, especially for the NLC, which provides a real added value in terms of biocompatibility with Caco-2 cells. Finally, the nanoparticles were able to penetrate into enterocytes by the transcellular route, demonstrating an intense cellular internalization.

Experimental investigation of heat transfer enhancement, thermal efficiency, and pressure drop in forced convection of magnetic hybrid nanofluid (Fe₃O₄/TiO₂) under varied magnetic field strengths and waveforms

Applying a magnetic field to influence convective flow of ferrofluids has become an efficient method for enhancing heat transfer in thermal systems, particularly in straight tubes. This study investigates the heat transfer properties of Fe₃O₄/TiO₂ nanofluids within a heated copper tube under varied magnetic field strengths and waveforms. Optimal magnetic field conditions were determined at 4 V and 60 Hz across all waveform types, as higher frequencies and voltages increased magnetic field intensity, thereby reducing heat transfer rates. Magnetic waveforms exerted differential influences on pressure drop, indicating varied nanoparticle alignment and turbulence levels, impacting fluid flow dynamics and viscosity. Higher nanoparticle concentration (0.1% vol) correlated with increased pressure drops across sine, square, and triangular waveforms, suggesting heightened flow resistance and potential nanoparticle agglomeration, thus reducing thermal efficiency. Conversely, lower concentrations exhibited enhanced thermal performance due to improved nanoparticle dispersion and reduced thermal resistance. At 0.1% vol, heat transfer enhancement without a magnetic field was 16.5%. The introduction of magnetic field waveforms attenuated this enhancement: 15.3% (sine), 13.26% (square), and 12.59% (triangular). Conversely, at lower volume fractions, heat transfer enhancements with magnetic fields exceeded those without at 0.05% vol, enhancements were 20.92% (sine), 21.3% (square), and 21.34% (triangular); at 0.025% vol, enhancements were 22.07% (sine), 22.3% (square), and 21.32% (triangular); at 0.0125% vol, enhancements were 27.87% (sine), 28.21% (square), and 26.74% (triangular); and at 0.0065% vol, enhancements were 22.24% (sine), 22.3% (square), and 24.49% (triangular).

Synthesis and Characterization of ZnO Nanoparticles by Pulsed Laser Ablation in Liquid Using Different Wavelengths for Antibacterial Application

In this paper, the synthesis of colloidal solution of ZnO nanoparticles by PLAL using an Nd: YAG laser with 1064 nm and 532 nm wavelengths is described. The optical, morphological, structural, wettability and antibacterial activities were studied. The XRD analysis showed the hexagonal wurtzite structure while the UV-vis indicated the blue shift of the absorption peak due to the surface plasmon of the nanoparticle, which showed significant changes in color behavior. The FE-SEM revealed a uniformed spherical shape with a partial size range of 20.50–21.48 nm for ZnO at 1064 and 57.08–59.87 nm for ZnO at 532nm. Also, the concentration measurement indicated that the concentration of ZnO prepared at 1064 nm is 26.7 μg ml-1 and 63 μg ml-1 at 532 nm due to the relevance of high energy to the Zn plate and little distortion in the water and high absorption of short wavelength. Finally, the optical density of the antibacterial activity has been investigated, and both concentrations have good antibacterial activity at 12 h. The ZnO prepared at 532 nm has higher antibacterial activity because it has a high concentration of nanoparticles for both S. aureus and E. coli. Finally, the cell viability for ZnO synthesis with both 1064 nm and 532 nm indicates that this material has high biocompatibility and could be used for medical applications.

Entropy analysis of mixed convective electro-magnetohydrodynamic couple-stress hybrid nanofluid flow with variable electrical conductivity in a porous channel

The paper presents a novel study to examine the irreversibility of quadratically mixed convective electro-magnetohydrodynamic (EMHD) flow of a couple-stress hybrid nanofluid (CSHNF) with variable properties in a vertical porous channel. The channel walls are exposed to an applied electric field effect and a uniform transverse magnetic field. The hybrid nanofluid considered is an ethylene glycol (C 2 H 6 O 2) base mixed with multi-walled carbon nanotubes (MWCNT) and silver (Ag) nanoparticles (NPs), assuming the base fluid and nanoparticles to be in a state of thermal equilibrium following the Tiwari-Das nanofluid model. The potential applications of the study can be in microfluidics to nanofluidics, particularly in developing cooling technologies, EMHD pumps, high-end microelectromechanical systems (MEMS), and lab-on-a-chip (LOC) devices used in bioengineering. A constant pressure gradient acting in the flow direction and the buoyancy effect under the quadratic Boussinesq approximation drive the flow. The governing momentum and energy equations are nondimensionalized using pertinent dimensionless parameters and solved by the semi-analytical homotopy analysis method (HAM). The entropy generation and the Bejan numbers are derived to examine the irreversibilities in the system. To investigate the rate of shear stresses and heat transfer, skin friction coefficients and Nusselt numbers on the channel walls are determined. The analysis emphasizes the influence of nanoparticle concentration and electromagnetic field on the flow dynamics, temperature distribution, and system irreversibilities in the presence of porous media. It reveals the enhancement of fluid velocity and temperature degradation for higher concentrations. In contrast, both reduce for higher magnetic and electrical strength. With the enhancement of electrical joule heating and quadratic convection, a higher entropy generation rate is attained with a low rate of heat transfer irreversibility. However, it reduces with higher nanoparticle concentration, electrical strength, porosity, and variable electrical conductivity parameters under the dominance of heat transfer irreversibility.

Effect of wastewater containing mixture of nanoparticles on organic matter removal, power generation, and biofilm integrity in sediment microbial fuel cell

ABSTRACT Industrial wastewaters from the cosmetic industry contain high organic strength and mixture of nanoparticles (NPs). Sediment microbial fuel cell (MFC) is an emerging nature-based technology that can treat complex wastewaters. The aim of this study is to understand the effect of a binary mixture of zinc oxide (ZnO) and copper oxide (CuO) NPs (concentration: 1 + 1 and 10 + 10 mg/L) on the organic matter removal, power generation, and biofilm health of sediment MFCs after a long-term operation of 120 days. The high chemical oxygen demand (COD) removal (&amp;gt;95%) observed for all reactors signified the minimal impact of 10 mg/L NP mixture on treatment. The dissolved organic carbon (DOC) removal from the sediment was reduced by 8% due to NPs. NPs also led to 42.2% higher anode extracellular polymeric substances (EPS) and 46.65% lesser cathode EPS generation. The maximum power density of 0.29 mW/m2 was obtained for the 10 mg/L NP reactor, with the average being 23% higher than the no-NP control reactor. This was the first study to explore the effect of the mixture of NPs on the performance of an MFC. The results indicated that sediment MFCs can sustain high mixture concentrations of NPs. Furthermore, variation of parameters can aid in establishing the feasibility of this technology for treating wastewater with NPs.

Evaluation of extraction and storage conditions for quantification and characterization of silver nanoparticles in complex samples by single particle-ICP-MS

The extraction of nanoparticles (NPs) from complex matrices and subsequent storage can potentially alter the NPs physicochemical properties and hinder cross-study comparisons. Most NPs extraction methods are designed and tested at high NPs concentrations, although (eco)toxicological and regulatory monitoring programs require methods capable of analyzing NPs at environmentally relevant concentrations (lower ppb range). In this study, we investigated how extraction methods affect the characteristics of PVP coated and citrate-stabilized silver NPs (AgNPs) spiked into soil, sewage sludge, and biological samples at environmentally relevant concentrations using Single Particle Inductively Coupled Plasma Mass Spectrometry spICP-MS). Further we investigated the impact of storage temperature (-80 °C – 21 °C) and storage duration (1–28 days) on the particle characteristics such as particle size.We found that aqueous AgNPs samples with low ionic strength media retained their original characteristics (like particle size, particle concentration and particle-based Ag mass) when preserved at 4 °C for up to 28 days. AgNPs dispersed in high ionic strength media were however better preserved at −80 °C. Among the extraction agents, tetrasodium pyrophosphate was efficient in extracting AgNPs from soil and sewage sludge matrices, while Proteinase K was most suitable for biological samples from organisms (earthworms or fish).Although our study focused only on AgNPs, it provides crucial information to aid interlaboratory comparisons and data interpretation for (eco)toxicological studies.

A novel green nanocomposite for EOR: Experimental Investigation of IFT Reduction, wettability Shift, and nanofluid stability

A stable nanofluid (NF) is crucial for success of nano-enhanced oil recovery (nEOR) processes. However, this represents a significant challenge as nanoparticles (NPs) tend to agglomerate under high salinity and NP concentration adversely affecting the oil recovery. New nanomaterials including functionalized nanoparticles also known as nanocomposites (NC) can help to overcome these issues. In this paper, first, we reported synthesis, characterization, and performance evaluation of a novel hydrophobic CuO-SiO2-Montmorillonite-K+-Thiazine NC for the first time. The NC was characterized using Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDAX), X-Ray Diffraction (XRD), Thermogravimetry Analysis (TGA), and Fourier Transform Infrared Spectroscopy (FTIR). SEM analysis showed that the NC is composed of uniformly distributed NPs. EDAX results confirmed presence of Cu, SiO2, O2, and Cl in the NC. XRD analysis indicated that SiO2 is the dominant phase in the crystal lattice and responsible for adsorption capacity of the NC. TGA analysis showed that the NC will be thermally stable in typical reservoir temperatures (∼80°C). FTIR results confirmed presence of Si-O, Cu-O, Si-O-Si, Al-O-Si, Al-OH, and OH bonds in the NC. In the second phase of this research work, the novel NC was used to investigate recovery of a Kazakhstani paraffinic heavy crude oil from Berea sandstone with focus on IFT reduction, oil recovery, wettability alteration, and stability analysis of the NFs. NFs were prepared with NC concentrations of 250, 500, and 1,000 ppm using moderate salinity (MS), low salinity (LS), and distilled water (DW). The results showed that the optimal NF (250 ppm LS) exhibited a high zeta potential value (−65.5 mV) indicating a high stability which is superior to all of the previously reported NCs. This high stability is attributed to use of thaizine as a source of natural surfactant. The optimum NF also altered the wettability of the sandstone by 77.6% and the contact angle (CA) was reduced from 117.9° to 26.4° making the system strongly water wet. The nanoclay has significantly facilitated the wettability alteration. The optimum NF also reduced the IFT by 92.3% from 27.42 mN/m to 2.11 mN/m. An incremental oil recovery of 20% was also achieved in the tertiary or EOR stage of oil. A comparison with the NCs reported in the literature confirmed the excellent performance of this novel NC in terms of NF stability, IFT reduction, and wettability alteration. The novel NC has a great potential for nEOR and other oilfield and environmental applications.

Evaluating the Thermal and Hydraulic Performance of Various Nanofluids for Cooling Efficiency in Diverse Heat-Sink Configuration

Using nanofluids in thermal applications is widely believed to enhance efficiency compared to conventional fluids, presenting the significant role of nanofluids as a crucial step in implementing energy-saving measures across various commercial applications. However, the selection of nanofluid concentration often lacks a systematic approach, with decisions made independently of specific application requirements, type of nanofluid, cost considerations, and economic factors such as energy cost and system lifetime. This study examines the thermal and hydraulic performance of four nanofluids (Al2O3, TiO2, CuO, and SiO2) in heat-sink configurations designed for cooling data center servers. The research quantifies the effects of these nanofluids across three heat-sink cross-sectional shapes—circular, square, and rectangular—by analyzing metrics such as maximum chip surface temperature and cross-sectional pressure drop over a range of Reynolds numbers and flow rates. Key findings reveal that the square cross-sectional shape achieves a balanced performance, optimizing thermal transfer with a moderate pressure drop, making it a promising option for data center applications. The rectangular configuration offers superior heat transfer but incurs higher pressure drops, suited for cases prioritizing cooling efficiency over energy cost. Al2O3 nanofluid demonstrated the highest thermal conductivity but also resulted in the greatest increase in pressure drop, especially at higher nanoparticle concentrations. These results offer critical quantitative insights into selecting appropriate nanofluids and geometric configurations for enhanced cooling performance in data centers, highlighting the trade-offs between cooling efficiency and hydraulic energy demands.

Influence of Silver Nanoparticle Integration on the Composition and Surface Properties of Acrylic Dental Resins Employed in Temporary Bridges

Background: Recognized widely for its irreversible effects, periodontal disease stands as one of the most prevalent conditions, particularly emphasizing the potential for permanent damage caused by gingivitis, extending to encompass the entirety of the supportive complex, including the connective tissue and alveolar bone. Patients necessitating comprehensive periodontal and prosthetic treatments require an interdisciplinary approach, involving the coordination of pre-treatment procedures and appropriate prosthetic strategies. The adoption of advanced materials and techniques can prove beneficial in addressing complex dental issues. (2) Methods: Forty specimens were prepared using the prescribed procedure, with 20 acting as controls and the other 20 integrating AgNPs. The initial step involved crafting wax patterns of distinct shapes: dumbbell shapes for tensile testing and rectangular shapes for roughness assessments. These dimensions were aligned with ASTM D-638 and ISO 527-2 standards and adjusted to match the specifications of the analysis device for mechanical properties. (3) Results: In this case, the results indicate minimal differences in heat-curing acrylic resins compared to the control samples at a 5% concentration. However, notable disparities arise at concentrations of 10% and 20%. (4) Conclusions: Temporary prosthetic constructions are essential for preventing functional imbalances and complications. Incorporating AgNPs at a 5% concentration maintains mechanical properties while providing antibacterial effects for long-term interim prosthodontic restorations. Higher nanoparticle concentrations may reduce resin mechanical properties without affecting material surface condition

Nanostructured materials as hazardous wastewater micropullutants: Sources, behavior, and impact on functional bacterial community of activated sludge

Unique properties of nanoscale materials make them attractive for industrial, medical, agricultural, and environmental applications. Nevertheless, the release of nanoparticles into the environment is a major concern due to the lack of knowledge about their behavior in the environment and potential widespread environmental impacts. On the one hand, nanomaterials are perceived as pollutants that may affect activated sludge microorganisms and, consequently, the efficiency of wastewater treatment processes. On the other hand, some nanomaterials can be intentionally added to activated sludge systems to improve their performance in terms of, e.g., sludge settling and removing heavy metals or organic pollutants. As a result, nanoparticles are frequently accumulated in wastewater, which is considered to be a major source of nanoparticle release to the surrounding environment. Processes that involve the action of activated sludge are used worldwide in wastewater treatment plants due to their excellent capacity of removing nutrients, degrading toxins, and retaining biomass. High concentrations of nanoparticles entering activated sludge systems can affect their growth and metabolism. The research studies, which are reviewed in the present article, show that nanoparticles significantly reduce the relative abundance of the activated sludge microbial community associated with nitrification, denitrification, and phosphorus removal. The knowledge about the structure of the activated sludge microbial community with an assessment of nanomaterial toxicity can contribute to optimizing the sludge population and improving the performance of wastewater treatment plants.

Evaluation of the Effects of High Silver and Copper Nanoparticle Concentrations on Vaccinium myrtillus L. under Field Conditions.

The extensive development of nanotechnologies has allowed nanoparticles to impact living systems through different pathways. The effect of single exposure to high concentrations of silver and copper nanoparticles (50-200 mg/L) on Vaccinium myrtillus L. under field conditions was investigated. Nanoparticle uptake in different segments of Vaccinium myrtillus L. was assessed by applying inductively coupled plasma-atomic emission spectroscopy and a particle-induced X-ray emission technique. Copper nanoparticles mainly accumulated in the roots and leaves, while silver nanoparticles showed a higher affinity for the roots and berries. The nanoparticles' effects on the pigments and antioxidant activity of the plant's leaves were also evaluated. The possible human health risk associated with the consumption of nanoparticle-contaminated berries was assessed. The results indicated that the consumption of berries contaminated with nanoparticles presented a low risk for human health.

Surfactant-Free Preparation of Conjugated Polymer Nanoparticles in Aqueous Dispersions Using Sulfate Functionalized Fluorene Monomers.

Conjugated polymer nanoparticles (CPNs) can be synthesized by a Suzuki-Miyaura cross-coupling miniemulsion polymerization to give stable dispersions with a high concentration of uniform nanoparticles. However, large amounts of added surfactants are required to stabilize the miniemulsion and prevent the aggregation of the nanoparticles. Removal of the excess surfactant is challenging, and residual surfactant in thin films deposited from these dispersions can reduce the performance of optoelectronic devices. We report a novel approach to prepare stable dispersions with no added surfactant using a fluorene monomer, 2,7-dibromo-9,9-bis(undecanesulfate)-9H-fluorene, with alkyl side chains terminated by negatively charged sulfate groups. This functionality mimics the structure of one of the most commonly used surfactants, sodium dodecyl sulfate (SDS). This charged monomer effectively stabilizes the miniemulsion through electrostatic repulsion without the use of any additional surfactant in molar ratios ranging from 2.0 to 20.0 mol % of total monomer content for the preparation of poly(9,9-dioctylfluorene) (PFO) and poly(9,9-dioctylfluorene-alt-bithiophene) (PF8T2). Incorporation of 5.0 mol % of the amphiphilic monomer gave stable dispersions with a surface potential below -40 mV and, and polymers with molar mass (Mn) above 10 kg mol-1. This method should be generally applicable to the preparation of dispersions of polyfluorenes for application in organic electronic and optoelectronic devices without the requirement for time-consuming processes to remove residual surfactant.

Green Synthesis of Iron Nanoparticles Using Spinacia oleracea and Their Role in Antioxidant Defence

The green synthesis of iron oxide nanoparticles (Fe2O3) using Spinacia oleracea leaf extract is explored in this study. Iron oxide nanoparticles are noted for their unique properties, such as enhanced chemical reactivity due to their high specific surface area to volume ratios. Unlike traditional physical and chemical methods, green synthesis presents an environmental friendly alternative, leveraging biological processes for nanoparticle production. This method is particularly significant due to its potential applications in various fields, including medicine, where iron nanoparticles demonstrate antibacterial activity. However, limited research exists on their antioxidant properties. In this research, Spinacia oleracea leaf extract is utilized to synthesize iron oxide nanoparticles, followed by characterization using UV-Visible spectroscopy, FTIR, XRD, and SEM techniques. The results underscore the necessity for further investigation into the impact of nanoparticles on biological processes and the long-term effects of high nanoparticle concentrations on ecological stability. Additionally, this study includes an evaluation of antioxidant properties of the nanoparticles to address gaps in current research. Key Words Green synthesis, iron oxide, ecological stability, antioxidant, biological, nanoparticles.