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Green Synthesis and Applications of Silver Nanoparticles using Sonchus asper Flower Extract

Nanoparticle (NP) synthesis is a dynamic, versatile and active field of modern nanotechnology research with numerous applications in various industries. In the current study, silver nanoparticles (AgNPs) were biosynthesized using the floral extract of Sonchus asper (Sa), a common edible and medicinal weed (native to Asia, Europe, Africa, North America and South America), which served as a reducing and stabilizing agent. The features of the biosynthesized SaAgNPs were examined using advanced characterization techniques. Their biomedical activities, comprising antibacterial, antioxidant, antidiabetic, and anti-inflammatory activities, and their biocompatibility were assessed via in vitro studies. As a result, the change of the yellow colour of the extract solution to brown after adding the aqueous AgNO3 solution confirmed the synthesis of SaAgNPs. FTIR spectra revealed the presence of phytochemicals, which served as reducing and stabilizing agents. SEM evidenced the spherical shape of the nanoparticles, with sizes in the range of 36-80 nm. The effective DPPH radical scavenging ability, biocompatibility and anti-inflammatory potential of the SaAgNPs were shown in a concentration-dependent manner (250-1000 µg/mL). Moreover, the biosynthesized AgNPs displayed maximum inhibition zones of 13.5 mm and 12.75 mm with a significant (p < 0.0001) inhibition against E.coli and S. aureus, showing effective antibacterial potential. Our study evaluates the toxicity and safety of SaAgNPs, including their potential interaction with human health and the environment, ensuring their safe use in various biomedical applications.

  • Open access
  • 9 Reads
Development of magnetic-responsive poly(ε-caprolactone) nanoparticles with potential applications in advanced cancer therapeutics

Cancer continues to be a major global health challenge and remains one of the leading causes of mortality. Early diagnosis and targeted treatment are essential, but often limited by insufficient precision and specificity. In this context, pharmaceutical nanotechnology has emerged as a promising field, offering significant advances in cancer diagnostics and therapy. Among the nanomaterials being investigated, iron oxides have garnered considerable interest due to their favorable magnetic properties and versatile biomedical applications. The aim of this work was to define a reproducible procedure to formulate haemocompatible maghemite/poly(ε-caprolactone) (γ-Fe2O3/PCL) nanoparticles with potential applications against cancer. γ-Fe2O3/PCL particles were prepared by emulsion/solvent evaporation. An extensive physicochemical characterization of the nanoparticles was carried out, including analysis of particle size, surface electrokinetics (zeta potential), and magnetic responsiveness. Particle size and surface electrical charge were characterized by photon correlation spectroscopy and electrophoresis, respectively. Ex vivo blood compatibility was also evaluated. Finally, the hyperthermia capacity of the nanocomposites was also evaluated. The γ-Fe2O3/PCL nanocomposites were in the colloidal range. Electrokinetic analysis confirmed the successful formation of the core/shell structure. In addition, the nanohybrids demonstrated favorable magnetic responsiveness and heating capacity, being they also hemocompatible. Thus, the γ-Fe2O3/PCL nanohybrids may enable magnetic-driven accumulation into the site of action and, probably, multifunctional capabilities for cancer therapy.

  • Open access
  • 6 Reads
Waste Valorization: Production of Nanocellulose Fibers from Agro-Industrial Mango Kent (Mangifera indica) Residues

This study proposes the utilization of mango peel residues from the Kent variety (Mangifera indica), generated by agro-industrial processes in Northern Peru (approximately 3,840 tons/year), for the production of cellulose nanofibrils (CNF), offering a value-added alternative for waste generated by agro-industries. The main objective was to determine the optimal CNF yield under two temperature levels: reaction time and sulfuric acid concentration. The raw material underwent the following pretreatment steps: immersion washing in water at 90 °C for 20 minutes, followed by drying and sieving. Subsequently, it was washed with 96% ethanol through steam stripping. An alkaline treatment with 8% NaOH was applied at a solid-to-liquid ratio of 1:15 at 75–80 °C for 4 hours with constant stirring at 500 rpm. For the bleaching stage, the fibers were treated with an equal-part solution of acetate buffer and aqueous sodium chlorite at 80 °C for 6 hours under continuous agitation. Afterward, a mechanical treatment was applied, followed by acid hydrolysis using sulfuric acid at varying concentrations (2%, 6%, 10%) with a 1:20 solid-to-liquid ratio, reaction times of 60 and 90 minutes, and temperatures of 60 °C and 80 °C. The resulting suspension underwent sonication in an ultrasonic bath (300 W) over ice for 30 minutes. The mixture was then subjected to successive washes with distilled water for dialysis, using dialysis membranes with a molecular weight cut-off of 12–14 kDa. Finally, the suspension was freeze-dried and sonicated again at –45 °C to obtain CNF particles. The resulting nanocellulose yields ranged from 86% to 99% (dry CNF weight/cellulose weight) and 18.35% yield based on dry residue weight (dry CNF weight/initial raw mass weight). The most efficient condition was achieved at 80 °C, 2% H₂SO₄, and 60 minutes of reaction time. This chemo-mechanical process represents a sustainable and low-cost alternative for biomaterial production from agro-industrial waste, contributing to environmental impact reduction.

  • Open access
  • 2 Reads
Diamond nanoparticles as a dispersion phase in Ni-P/diamond composite coatings produced by chemical reduction
, , , , , , , ,

Nanoparticles are a group of materials that have become increasingly important in recent years. In surface engineering, nanoparticles can be used as a dispersion phase incorporated into a metal matrix to improve the properties of composite coatings. By selecting the type of particles and their shape, the properties of the final products can be modified. The use of carbonaceous materials with nanometric dimensions appears to be of particular interest. Several papers [1-4] have been published that study the incorporation of particles such as graphene, graphite, carbon nanotubes, or diamond. The latter, due to its very high hardness, can significantly improve the mechanical and tribological properties of metal coatings.

This paper presents the results of a study on Ni-P/diamond composite coatings as well as Ni-P coatings without embedded particles for comparison. The coatings were produced by a chemical reduction from multi-component bath solutions on steel substrates. Characterization of the nanodiamond used is presented in this study (SEM, XRD). The morphology and surface topography were investigated by SEM, light microscopy, and measurements of roughness parameters. The structure of the investigated coatings was characterized by XRD. The hardness of the produced coatings was tested using the Knoop method (HK0.01). Tribological tests were conducted using the ball-on-disc method. The adhesion of the developed coatings to the substrate was tested using the scratch test method.

The incorporation of nanodiamonds into an alloyed Ni-P matrix alters the morphology and surface topography of the materials produced. Composite coatings with diamond exhibit higher hardness and a lower coefficient of friction compared to Ni-P coatings without embedded particles.

Funding: The presented research was financed by the earmarked grants awarded by the Łukasiewicz
Center, grand contract no 2/Ł-IMP/CŁ/2021. The title project: New generation thermally conductive
layers for electronics and the technology of their production.

[1] Materials 2024, 17, 2803.

[2] Tribology International 2024,198, 109905.

[3]Applied Surface Science Advances 2022, 11, 100310.

[4] Surface and Coatings Technology 2019, 359, 141-149.

  • Open access
  • 3 Reads
Anomalous behaviour of refractive index: a case study through photoluminescence properties of Eu3+-doped tungstate phosphor
, , , ,

In the present study, the investigation of excitation-dependent emissions of europium (Eu3+)-ion-doped bismuth tungstate phosphor (BiLaWO6) and relative effects is discussed in detail. Several findings from the diffuse reflectance spectra (DRS) indicate the electronic transitions related to charge transfer bands (CTB) and ligand-to-metal charge transfer (LMCT) processes. The photoluminescence (PL) spectra, observed under different excitation wavelengths, revealing distinct Eu³⁺ ion transitions (f - f intraconfigurational) and varying emission intensities. The decay profiles of Eu³⁺ luminescence displayed wavelength-dependent behaviour, with decay times decreasing with the increase of excitation wavelength. This behaviour is attributed to varying contributions of non-radiative (NR) energy transfer processes and direct excitation of Eu³⁺ ions. An indirect approach of calculating the Judd-Ofelt (J-O) parameters has been employed. The refractive index (RI), calculated indirectly from the emission intensity data, showed a non-monotonic variation with excitation wavelength, peaking at a specific wavelength. This indicates that Eu³⁺ ions can serve as effective probes for investigating material optical properties near the bandgap. The results from this work ascertain that, Eu3+ ion can not only be used as a spectroscopic probe but also to probe the behaviour of material and its variation of refractive index near the bandgap (Eg) of the material.

  • Open access
  • 18 Reads
Comparison of the Conjugation Efficiency of 10-23 Deoxyribozyme with Streptavidin-Coated and Carboxyl-Functionalized Magnetic Nanoparticles

Magnetic nanoparticles (MNPs) are widely used in the development of biosensors for nucleic acid detection. Efficient immobilization of bioreceptors, such as DNA enzymes (deoxyribozymes, Dz), on the surface of MNPs is critical for sensor sensitivity. The aim of this work is to compare the conjugation efficiency of 10-23 deoxyribozyme with two widely used types of MNPs: streptavidin-coated (Strep-MNPs) and carboxyl-functionalized (COOH-MNPs).

We used biotin-modified (biotin-Dz) and amino-modified (NH₂-Dz) 10-23 Dz. The linear fluorescence range (λexem = 480/525 nm) versus Dz concentration (0–1000 pM) was established by cleavage of a fluorogenic substrate (200 nM) in Col buffer (55°C, 1 h and 3 h). Conjugation of 20 nM Dz with Strep-MNPs (1 mg/mL) was performed in Col buffer (60 min, RT), with unbound Dz removed by washing (3x, Col buffer, magnetic separation). Conjugation of NH₂-Dz with COOH-MNPs was performed after EDC/NHS activation in Col buffer (30 min, RT), followed by Dz addition (2 h) and washing. A TTT oligonucleotide served as a non-specific binding control. After conjugation and washing, 200 nM substrate was added to MNPs, incubated for 1 h and 3 h (55°C), and fluorescence was measured. Conjugation efficiency was calculated as the activity of immobilized Dz (via calibration curve) relative to the activity of the initial 20 nM Dz solution.

Linear fluorescence ranges were as follows: biotin-Dz (0–50 pM, 1 h; 0–100 pM, 3 h); NH₂-Dz (0–1000 pM, 1 h; 0–100 pM, 3 h). After 1 h substrate incubation, we obtained the following percentages: biotin-Dz/Strep-MNPs: 0.32%; NH₂-Dz/COOH-MNPs: 0.07%. After 3 h, activity decreased to 0.02% for biotin-Dz/Strep-MNPs. The TTT conjugation efficiency was negligible (<0.01%).

Conjugation of 10-23 Dz using specific biotin–streptavidin binding (Strep-MNPs) was ~4.6 times more efficient than covalent amide binding (COOH-MNPs) under the tested conditions. Activity reduction during prolonged incubation may result from Dz inactivation. Streptavidin-coated MNPs are a preferred carrier for immobilizing biotin-modified 10-23 deoxyribozyme compared to carboxyl-MNPs. These findings are essential for developing high-performance Dz-based biosensors using magnetic nanoparticles.


This study was supported by grant FSER-2025-0019.

  • Open access
  • 5 Reads
Coaxial fibers modified with grape extract endowed with halochromic properties for potential detection of infection state in burns.

Burn wounds are among the most common and dangerous skin injuries for humans, causing denaturation of skin proteins and imposing serious constraints to the daily tasks of humans.

In recent years, the wet-spinning technique has been used in medical applications, such as wound dressings, due to its ability to generate nano- and microscale structures with different levels of organization, with open pores to improve cell interaction and with a set of chemical and physical properties that can be tuned to ease the process of cell maturation.

In this work, the development of coaxial fibers using the wet-spinning method for potential applications in burn treatment is proposed. The fibers were processed from biocompatible polymers with a core–shell structure.

The outer layer was made of cellulose acetate (CA) and polycaprolactone (PCL) modified with grape extract endowed with halochromic properties for detecting the level of infection of a potential burn. The inner layer was formed by sodium alginate (SA) loaded with natural extract (e.g., cinnamaldehyde) to combat infections and to endow the system with antioxidant properties to stimulate the regeneration of damaged cell tissue.

A color change was observed when solutions with different pH values, between 3 (light pink) and 10 (dark blue), were applied to the grape extract-loaded coaxial fibers. The coaxial structure was confirmed by brightfield microscopy and the elements composing the fibers were identified by Fourier-transform infrared spectroscopy. Antibacterial tests proved the bioactive agents’ inhibitory action, above 70%, against the bacteria Escherichia coli and Staphylococcus aureus. Antioxidant examinations attested to their ability in reducing 2,2-diphenyl-1-picrylhydrazyl. Data demonstrated the effectiveness of the engineered coaxial fibers for potential applications in burn wound care.

  • Open access
  • 13 Reads
Combustion synthesis of ZTO nanostructures
, , , , , ,

Ternary oxides like ZTO have attracted much attention as a green alternative to typical semiconductor technologies. ZTO has a wide variety of applications, but its current production methods, (vapor-based depositions and hydrothermal) are complex and involve high pressures and long reaction times. Solution Combustion Synthesis is a great candidate to overcome these issues, allowing to reduce the complexity of producing ZTO nanostructures. Solution combustion synthesis was used to produce ZTO- and ZTO-Ag-doped nanostructures. Precursor solutions of ZnO and SnO were produced and mixed in several ratios to form a ZTO precursor solution. The solutions were placed in a furnace, the synthesis was performed at 300ºC, and several annealing temperatures were explored. ZTO powders presented a mixture of ZnO, SnO2, and ZnSnO3 phases. When increasing the annealing temperature, a crystallinity increase and the growth of different nanostructures were observed. In order to obtain a pure ZTO phase, the influence of the surfactant in the growth of the nanostructures was studied using EDA but the formation of ZnO was favoured. Doping ZTO with silver might bring interesting advantages for electronic applications, therefore ZTO-Ag nanostructures were also produced. The use of silver nitrate led to the precipitation of SnCl2. ZTO-Ag doped powders revealed the dominance of the ZnO phase. Finaly, the Zn:Sn ratio was confirmed to be identical to the Zn:Sn ratio of the ZTO precursor solution. The obtained results proved that solution combustion synthesis is a reliable method to produce ZTO nanostructures and can be a low-cost, green, alternative to typical production methods.

Branquinho, et al,(2016). Solution Combustion Synthesis: Applications in Oxide Electronics https://doi.org/10.5772/64761

Rovisco, et al,(2018). Seed-layer free zinc tin oxide tailored nanostructures for nanoelectronic applications: Effect of chemical parameters https://doi.org/10.1021/acsanm.8b00743

  • Open access
  • 12 Reads
Enhanced Electrochemical Performance of Hard Carbon Anodes via Oxygen-Rich Nano-Graphene Oxide for Sodium-Ion Batteries

Sodium-ion batteries (Na-ion batteries) have emerged as a promising alternative to lithium-ion batteries due to sodium’s natural abundance, low cost, and compatibility with existing lithium-based infrastructure. As the global demand for cost-effective and sustainable energy storage solutions increases, Na-ion systems are gaining considerable attention. However, their commercial viability is currently hindered by challenges such as low energy density, poor rate performance, and limited long-term cycling stability. To address these limitations, the development of advanced electrode materials and functional additives is crucial. In this study, an oxygen-rich nanostructured graphene oxide (OR-NGO) material was synthesized via a modified Hummers method and incorporated into hard carbon (HC) anodes to improve electrochemical performance. Unlike typical carbon-based additives that rely primarily on increasing surface area, OR-NGO enhances the electrode function through its high concentration of redox-active oxygen functional groups and increased edge site exposure. These characteristics facilitate additional pseudocapacitive Na⁺ storage and improve both ionic and electronic transport at the electrode–electrolyte interface. To optimize its effect, three additive loadings (0.5, 1.0, and 1.5 wt%) were evaluated, with the 1.0 wt% OR-NGO sample exhibiting the most favorable electrochemical characteristics. The composite electrode demonstrated enhanced reversible capacity, superior rate capability, and improved cycling retention compared to pristine hard carbon. These findings highlight the synergistic role of chemical functionalization and nanoscale structuring in OR-NGO, underscoring its potential as a high-performance additive. This strategy offers a promising pathway for advancing sodium-ion battery technologies toward practical applications in large-scale energy storage systems.

  • Open access
  • 12 Reads
CO₂ Capture on Amine-Modified Mesostructured Silicas: A Comparative Study with Metal–Organic Frameworks

Within the Carbon Capture and Utilization technologies framework, porous materials—such as Ordered Mesostructured Silicas (OMSs) and Metal–Organic Frameworks (MOFs)—are promising sorbents for CO2 capture due to their high adsorption capacities, ease of regeneration, and stability. This work focuses on a comparison between two classes of hybrid organic–inorganic adsorbents for CO2 capture: amino-modified OMSs and MOFs. Among the OMSs, two MCM-41 samples composed of 100–500nm particles with 3 nm mesopores were synthesized using different silicon sources: TEOS (tetraethyl orthosilicate) and FSA (fluorosilicic acid) derived from industrial waste. Owing to their high surface area resulting from their mesostructure, these materials are well-suited for surface functionalization to improve CO₂ adsorption. In this study, both samples were functionalized with (3-aminopropyl)triethoxysilane, yielding NH₂@TEOS-MCM-41 and NH₂@FSA-MCM-41. For comparison a 3D ultramicroporous MOF based on a benzoquinone derivative—3,6-N-ditriazolyl-2,5-dihydroxy-1,4-benzoquinone (trz₂An)—coordinated with cobalt(II) (CoMOF) was proposed. Its pore size (3.4 Å) enables selective CO₂ separation via size-dependent adsorption (molecular sieving), as this dimension closely match the kinetic diameter of CO₂. CO2 capture performance was assessed through dynamic adsorption tests using 5–10% CO2 in N2. At 10% CO₂ and 30 °C, NH₂@TEOS-MCM-41 showed a higher uptake (~1000 μmol/g) than CoMOF (~700 μmol/g), with the difference becoming more pronounced at 5% CO₂: ~829 μmol/g and ~317 μmol/g respectively. Conversely, CoMOF offered easier regeneration at room temperature under N2, whereas NH2@TEOS-MCM-41 required also heating at 120 °C. The different performances arise mainly from their distinct CO2 adsorption mechanisms: chemisorption for NH2@TEOS-MCM-41, forming ammonium carbamates through interactions between amino groups and CO2 and physisorption for CoMOF, governed by weak intermolecular forces with MOF’s porous surface. The adsorption heats derived from microcalorimetry and the FTIR confirm the mentioned mechanisms. Additionally, NH2@FSA-MCM-41, synthesized from FSA with similar amine loading, showed even better performance: ~1000 μmol/g (5% CO2) and ~1200 μmol/g (10% CO2).

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