In recent years, selenium nanoparticles have received great interest owing to their potential applications in several fields, such as medicine, optoelectronics, agriculture, and catalysis [1]. Recently, we reported the efficient biogenic synthesis of nanoparticles anchored on carboxymethylcellulose (CMC) nanocolloids [2] [3]. Herein, we present a simple and ecofriendly method for the synthesis of selenium nanoparticles (SeNPs) using selenium dioxide (SeO₂) as a precursor, L-ascorbic acid (AA) as a reducing agent, and sodium carboxymethylcellulose (CMC-Na) as a biobased surfactant. Various synthesis parameters, i.e., the pH, AA equivalence (eqv.), and CMC weight, were optimized for the synthesis of the nanocolloids CMC@SeNPs. The optimum results were obtained using a 2,4 mmol/L solution of H₂SeO₃ at pH = 8 with 3 eqv. of AA and 222 mg of CMC. The as-prepared nanocolloids were characterized using various techniques, such as UV–visible spectroscopy, FTIR spectroscopy, XRD, zeta potential measurement, and FESEM-EDX. The results showed that SeNPs were successfully synthesized with a spherical shape and crystalline structure. Moreover, the as-synthesized CMC@SeNPs were studied to determine their suitability for use as smart fertilizers for agricultural applications.

References:

[1]: A. Hussain, M. N. Lakhan, A. Hanan, I. A. Soomro, M. Ahmed, F. Bibi, I. Zehra, Materials Today Sustainability, (2023), 23, 100420.

[2]: A. A. Mekkaoui, H. Orfi, K. Bejtka, M. Laayati, S. A Labyad, L. El Firdoussi, S. El Houssame, Environmental Science and Pollution Research, (2023), 30(34), 81619-81634.

[3]: H. Orfi, A. A. Mekkaoui, B. Sündü, M. Laayati, S. A Labyad, L. El Firdoussi, S. El Houssame, J Inorg Organomet Polym Mater, (2022), 32:2192–2208.

The capacity of chitosan to form hydrogels under mild conditions and its chemical modifiability have made it widely used in drug delivery, wound healing, and tissue engineering. In recent years, particular attention has been directed toward chitosan-based nanocomposite hydrogels, which incorporate nanoparticles to enhance mechanical, biological, and functional properties. Chitosan-based nanocomposite hydrogels reinforced with nanoparticles were reviewed based on research articles retrieved from scientific databases, including PubMed, Web of Science, Scopus, ScienceDirect, Wiley Online Library, and Google Scholar.
The synthesis approaches are generally classified into ionic gelation, covalent crosslinking, and in situ nanoparticle formation. Ionic gelation relies on electrostatic interactions between the positively charged amino groups of chitosan and multivalent anions, enabling hydrogel formation without the use of toxic solvents or initiators. Covalent crosslinking methods involve the formation of stable chemical bonds between chitosan chains and crosslinkers, often leading to improved mechanical stability and long-term integrity. In situ nanoparticle formation refers to the generation of nanoparticles directly within the hydrogel matrix, allowing uniform dispersion and strong interfacial interactions with the polymer network.
Incorporated nanoparticles serve multiple roles: reinforcing the hydrogel network, enhancing antibacterial activity, or imparting specific functionalities such as magnetism or photothermal responsiveness. Critical formulation parameters greatly influence the resulting hydrogel’s mechanical strength, swelling behavior, porosity, and drug release kinetics. Additionally, blending chitosan with other natural polymers improves structural versatility and enables the design of injectable, self-healing, or stimuli-responsive nanocomposite systems.
In conclusion, the ability of chitosan-based nanocomposite hydrogels to combine bioactivity, controlled release, and structural integrity highlights their potential as next-generation materials in nanomedicine. Continued advances in synthesis methods, nanoparticle engineering, and biopolymer integration are expected to expand their clinical relevance and translational potential.

The rapid and modular assembly of hybrid nanosystems is central to the development of advanced nanomedicines, particularly for solid tumors such as neuroblastoma. While strain-promoted azide–alkyne cycloaddition (SPAAC) has emerged as a powerful tool for catalyst-free, bioorthogonal conjugation, its full potential remains constrained by the need for precise temporal control over fast-reacting systems1.
In this study, we present a custom-designed microfluidic device fabricated from polylactic acid (PLA) using affordable fused filament 3D printing technology2. The chip allows continuous-flow processing with well-defined residence times, enabling highly reproducible nanoassembly workflows. This setup was employed to drive SPAAC-mediated coupling between azide-functionalized mesoporous silica nanoparticles (MCM-41) or azide-functionalized liposomes and various DBCO-bearing entities: gold nanorods, catalase-loaded nanocapsules, and a fluorescently labeled small molecule (DBCO-Fluor 545). These components were selected to span a range of structural and chemical properties, particularly regarding differences in particle rigidity and steric impedance.
Reactions were limited to a 5-minute residence time in both the microfluidic and conventional agitation conditions. Differential centrifugation was used to isolate assembled nanostructures and remove excess reactants. The microfluidic chip consistently enabled efficient and reproducible conjugation across all systems tested, despite the rapid kinetics and low reagent concentrations typically required for biocompatible settings.
Our results demonstrate that the microfluidic system provides a robust and reproducible platform for the rapid generation of hybrid nanoassemblies. Without requiring elevated concentrations or extended reaction times, this strategy enabled the formation of covalently linked nanosystems across all tested configurations. The method offers a scalable and modular route to the fabrication of functional nanomaterials, with potential applications in drug delivery, enzyme immobilization, intracellular trafficking, and targeted cancer therapy.

Bibliography:
1.
Sletten, E. M. & Bertozzi, C. R. Bioorthogonal Chemistry: Fishing for Selectivity in a Sea of Functionality. Angewandte Chemie International Edition 48, 6974–6998 (2009).
2.
Whitesides, G. M. The origins and the future of microfluidics. Nature 442, 368–373 (2006).

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.

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.

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.

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.

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 (E_g) of the material.

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 (λ_ex/λ_em = 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.

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.