Nanoparticles have gained significant attention as a cost-effective and robust alternative to natural enzymes. Their stability makes them suitable for a wide range of applications in medicine, science, and industry. Horseradish peroxidase (HRP) plays vital roles in biological systems by catalyzing substrate oxidation in the presence of hydrogen peroxide (H₂O₂). However, HRP is affected by harsh conditions of pH and temperature. In this work, carbon dots doped with metals (X-CDs) are utilized as nanozymes, mimicking the function of horseradish peroxidase (HRP) to some extent. Cobalt (Co), Nickel (Ni), Iron (Fe), and Copper (Cu) are used as the carbon dot-doping materials. X-CDs are synthesized from inexpensive chemicals in just a few steps, saving time and costs and showing better robustness. A total of 0.25 m mole of metal acetate was mixed with 87 mg L-Arginine, 80.6 µL Amine, and 100 µL distilled water at 240°C, for 3 minutes, and was then purified by a 0.5-1 kDa MWCO membrane against 1 liter of distilled water for five days. The peroxidase- like activity of the nanozymes was investigated by measuring the absorbance of TMB solution at 652 nm in the presence of H₂O₂. The results showed that X-CDs had a maximum ability to catalyze TMB in acidic buffer media at pH=4. High temperatures did not destroy the internal system of the X-CDs. Also, the X-CDs did not lose their activity after 3 months of storage at 4 C. To conclude, nanozymes exhibit evident peroxidase activity, which in some ways can be compared to the activity of horseradish peroxidase (HRP), with excellent stability at harsh pH and high temperature. They maintain their activity even after months, and they do not need to be stored at low temperature, nor do they need stabilizers. These features can be employed in biosensing by conjugating nanozymes to antibodies, where they appear in color as a sign of their presence.

Agricultural disease control faces serious hurdles due to the increasing resistance of pathogens and the banning of synthetic plant protection products (PPPs), resulting in environmental and public health risks. In this context, biodegradable nanocarriers derived from macroalgae (Bio-MACs), such as functional polysaccharides and proteins (e.g., alginic acids, chitosans, and carrageenans), offer promising technical solutions. The efficient encapsulation and controlled release of bioactive metabolites with antifungal, antibacterial, and biostimulant properties can be achieved using these nanocarriers. The developed systems protect the active ingredients from degradation, prolong their efficacy in soil, and minimize soil and water contamination by reducing application doses by up to 40%. Furthermore, these systems exhibit low toxicity to non-target organisms, such as Daphnia magna and Eisenia fetida, in accordance with the OECD TG 202 and 207 guidelines. Bio-MACs have regulatory advantages over synthetic nanoparticles because they are generally recognized as safe (GRAS), non-toxic, non-reactogenic, widely available and highly biodegradable. These characteristics make them uniquely suited for use in the food and agricultural industries, where sustainability is critical. Moreover, the economic potential and marketability of Bio-MACs are booming, particularly given the rising demand for eco-friendly agricultural inputs and the rapid expansion of the biopesticides sector, which is set to hit USD 10 billion by 2027. However, successful market integration requires acknowledging and addressing challenges such as public and regulatory concerns surrounding nanotechnology. This requires standardizing production protocols and conducting large-scale field trials to demonstrate the effectiveness and safety of nanotechnology. Thus, the objective of this systematic review is to explore the potential of Bio-MACs for encapsulating and releasing biological metabolite activities.

Metal–organic frameworks (MOFs) with strong metal–ligand interaction are acceptable as a coordination polymer. They are porous and crystalline materials. Besides that, their surface area and pore volume can increase to 5900 m²/g and 2 cm³/g. MOFs have many topologies and pore sizes, and over 100,000 types of MOFs have been discovered up until now. There are a wide variety of application areas of MOFs. They have been used in catalysis, biomedical applications, chemical sensing, gas separation, and storage. Determining the topological features is important in revealing the porosity and mechanical properties of MOFs. It is also known that improving crystallinity paves the way for an increase in the porosity and surface area of MOFs. Hence, this study aimed to unveil the crystallographic features of some popular MOF types such as ZIF-8, ZIF-67, and UiO-66. The crystal data, bond length and angles, and crystal structure of the selected MOFs were identified by using ToposPro software. Besides that, some simplifications to the topology of the MOFs were made by utilizing ToposPro. Simplification included removing hydrogen atoms from the structure. Thus, a clear version of the structure was obtained. The crystallographic data observed with ToposPro was compared to data found in the Cambridge Structural Database (CSD). ToposPro is a new topology tool, so research is scarce on this topic for MOFs.

Introduction: Carbon dots (C-dots) are biocompatible, photoluminescent nanoparticles composed mainly of carbon, hydrogen and oxygen. They can be synthesized via pyrolytic decomposition of various precursors, including polymers, small organic molecules and biomass waste (1,2). Their chemical composition, size, shape and macroscopic properties are largely impacted by reaction parameters such as temperature, precursor concentration and duration.

Methods: C-dots were derived via pyrolytic treatment of citric acid and urea and were purified via dialysis, centrifugation and filtration before being subjected to post-synthesis hypochlorite treatment (3,4). They were characterized using a combination of spectroscopic and microscopic techniques such as TEM, XRD, FTIR and XPS. Their photoluminescent properties, cytotoxicity and antimicrobial activity were systematically evaluated.

Results: We demonstrate that varying the molar ratio of precursors and applying standard size-separation methods yields materials with strong photoluminescence in both liquid and solid states as well as advanced antimicrobial properties. The direct NaClO treatment of C-dots causes significant surface oxidation and etching, which is a process that reduces UV-vis absorbance, increases the quantum yield sixfold and greatly enhances antifungal activity.

Conclusion: We present a low-cost, time-efficient strategy to generate a range of highly photoluminescent materials based on C-dots. The resulting materials are promising candidates for various applications, including bioimaging, biosensing, antimicrobial treatment, environmental sensing and remediation, forensic science and optoelectronics.

References

1. A. Kelarakis, Current Opinion in Colloid and Interface Science 2015, 20, 354
2. A. Kelarakis MRS Energy and Sustainability, 2014, 1, E2
3. J.D. Stachowska, A. Murphy, C. Mellor, D. Fernandes, E. Gibbons, M. Krysmann, A. Kelarakis, E. Burgaz, J. Moore and S. G. Yeates, Scientific Reports, 2021, 11,10554
4. S. Gavalas, S. Beg, E. Gibbons, A. Kelarakis, Nanomaterials 2025, 15, 184

Green chemistry methods have clearly revealed the definite demands for chemical procedures in performing ecofriendly synthesis using so-called biogenic compounds (BGCs) extracted from biological resources, such as fungi, algae and plantae. These compounds can potentially be used as reducing and stabilizing agents in nanoparticle (NP) synthesis. Modern research in the field of NP synthesis increasingly goes beyond traditional thermodynamic and kinetic approaches. More complex interactions are considered, which are organized according to the analog principle in the environment where nanoparticles with a given morphology are formed. The media state where chemical reactions occur could be viewed as manifestations of specific conformational BGC changes, which influence NP formation with its defined morphology. In this work, the reaction media is considered not only as a chemical system but also as a kind of analog processing unit, where pH, temperature, and spectra (the environment parameters) are the input data, while the size and shape of the nanoparticles formed (the morphology parameters) are the output data. The presented approach allows us to focus on information structure analysis, where each media state transition is associated with a change in the BGC conformational structure which, in turn, affects the size and shape of the NP formed.

Introduction

Chalcogens elements like Selenium (Se) and Tellurium (Te) have garnered significant interest within the scientific community due to their multidisciplinary applications in opto-electronic, bio-medicine and energy devices. Indeed, both (Se and Te) have been identified as energy-critical elements by the American Chemical Society and Materials Research Society. They both are rare earth elements that possess the same crystal structure with a chiral nature. When both of them are mixed, they easily form a totally miscible binary alloy, giving rise to unique properties like a tunable bandgap, stability, and high mobility, demonstrating their potential for use in high-performance opto-electronic devices. In this report, SeTe nanorods were synthesized for the first time by using the "bottom-ablation" Pulsed Laser Ablation in Liquids (PLALs) technique. PLALs is acost-effective and green technique that is used to produce nanoparticles with high purity in comparison to wet chemistry methods. Additionally, PLALs also helps to generate nanostructures with desirable phases, shapes and sizes.

Method

Bulk Selenium–Tellurium (SeTe) targets (99.999% purity) were immersed in a 50 ml single-neck glass flask containing 10 ml of acetone. The SeTe targets were irradiated for 5-minutes using a Nd:YAG laser, emitting at 1064 nm and pulsing at 1 kHz. The average laser power was 12.5 W, with an energy of 12.5 mJ/pulse at 1 kHz. The average beam spot size was measured to be around ~ 110 ± 28 μm, delivering a fluence of around ~131 ± 33 Jcm^-2.

Results

Finally, after 5 minutes of irradiation, monodispersed hexagonal-shaped TeSe nanorods were produced. The crystal structure of those nanorods is hexagonal. The bandgap was measured to be around ~ 2 eV.

Conclusions

Here, we reported the synthesis of the TeSe nanorod for the first time using the PLAL technique. Those synthesized rods were characterized by Scanning Electron Microscopy, X-ray Diffraction, and Raman and Photoluminescence Spectroscopy. Those rods will hold great potential for advancing the development of high-performance solar cells and photodetectors.

Bismuth antimonide (BiSb), a narrow-bandgap semiconductor, has attracted considerable interest for quantum applications due to its remarkable band structure and unique electronic properties. Composed of group V semimetals Bismuth (Bi) and Antimony (Sb), this miscible binary alloy forms a fully solid solution throughout the entire composition range. This material exhibits insulating behavior in its bulk and displays conducting surface states, making it the first experimentally observed 3D topological insulator. The alloy’s composition plays a crucial role in shaping its electronic band structure. Indeed, Bi_1-xSb_x undergoes a series of changes in its electronic structure as the Sb concentration increases: transitioning from a semimetal to an indirect bandgap semiconductor, followed by a direct bandgap semiconductor, then back to an indirect bandgap, and finally to a semimetal.

A BiSb target in pellet form (99.99% purity, from Sigma-Aldrich), cleaned with acetone, was placed at the bottom of a 50 mL single-neck round-bottom flask and submerged in 10 mL of acetone. Bottom ablation was carried out using a Q-switched Nd: YAG laser from Electro Scientific Industries operating at 1064 nm with a repetition rate of 1 kHz for 5 minutes. Morphological and structural properties were analyzed using HRTEM, EDX, Raman, XRD, UV-Vis, zeta potential, and DLS.

The size of the QDs was centered around 9 ± 2 nm and was spherical in shape. The bandgap was measured to be around 2.02 ± 0.27 eV, which is significantly higher than the bulk value. Strong evidence of quantum confinement was observed, as indicated by the peak shift in the Raman spectrum.

BiSb quantum dots were successfully synthesized for the first time using the PLAL technique. The QDs exhibited a spherical shape with a size of around 9 ± 2 nm and a significantly increased bandgap of approximately 2.02 eV, indicating strong quantum confinement effects. These results highlight the potential of BiSb QDs for quantum and optoelectronics applications.

Abstract: High-performance thermoplastics are lightweight and possess excellent mechanical properties over a wide temperature range. Composites of these materials and carbon nanotubes are expected to enhance mechanical performance while providing thermal and electrical conductivity. Polyether ether ketone (PEEK) is a lightweight, bioinert, high-performance thermoplastic with a wide range of applications in different fields, such as aerospace and biomedical devices. Sulfonated polyether ether ketone (SPEEK), which is obtained through sulfonation of PEEK, is a promising material for replacing traditional perfluorosulfonic acid membranes due to its excellent thermal stability, mechanical properties, and proton conductivity. Owing to their superior physical properties, carbon nanotubes (CNTs) can be introduced into PEEK and SPEEK matrices in order to further improve their conformances, opening up new perspectives for the development of the next generation of high-performance multifunctional materials.

Functionalization of CNTs provides a good approach to developing superior composite materials with enhanced mechanical properties. This process may enable interactions between the polymer matrix and CNTs to be controlled by using different functional groups attached to the nanotubes.

In this study, we present the covalent functionalization of pristine multi-walled carbon nanotubes (P-MWNTs) with poly(ether ether ketone) (SPEEK) chains, employing hexane diamine as an interlinking molecule. Both pristine and functionalized MWNTs (F-MWNTs) were then used to create PEEK/CNT and SPEEK/CNT composites. We used FTIR and NMR spectroscopy to confirm the covalent attachment of the SPEEK chains to the MWNTs and SEM and TEM to characterize the morphology of the functionalized tubes and composites. We evaluated the composites in terms of their structure, mechanical properties, and fracture morphology.

Our results show that SPEEK/F-MWNT composites with 2% F-MWNTs by weight exhibited a 7.1% improvement in their tensile modulus compared to SPEEK/MWNTs. However, the tensile modulus of PEEK/F-MWNTs increased by only 1.2%, while their tensile elongation decreased drastically.

Nowadays, the number of publications containing the keyword "hydroxyapatite" for the 2024-2025 period is more than 10,000 (according to ScienceDirect) due to the extensive use of this material. Hydroxyapatite is the main component in the framework for effective bone tissue regeneration because of its high biocompatibility and unique microstructure. Partial cationic substitution with rare earth elements (REEs) improves the characteristics of the original material and stimulates osteogenesis processes.

In this work, synthesis of Sm³⁺-, Pr³⁺-, and Gd³⁺-doped HA (with 6%/9% REEs) was performed. The solid phase was obtained through precipitation from aqueous solutions of calcium and REE nitrates, (NH₄)₂HPO₄. The powders were synthesized at a temperature of 70°C and a constant pH=11; dried at 100 °C; and calcined at 800 °C for 1 hour. The obtained materials were analyzed using IR–Fourier spectroscopy and XRD. The surface morphology and elemental composition were studied using SEM and EDS. The specific surface area indices were obtained using the BET method. The degradation of the materials in isotonic and tris-buffer solutions was also studied.

As a result of the investigation of the physicochemical properties, the materials were identified as a pure HA phase. They were nanosized particles connected in aggregates with many interaggregate pores. The IR spectra of the samples revealed bands of vibrations of carbonate and phosphate groups and vibrations of water in the structure. According to EDX, a decrease in the characteristic Ca/P ratio was noted, which confirmed cationic substitution in the Ca²⁺ positions.

Consequently, nanocrystalline hydroxyapatite doped with REE ions was synthesized through precipitation from aqueous solutions. It was found that the introduction of Pr³⁺, Sm³⁺, and Gd³⁺ affected the morphology and size of the particles. This system can be considered as a prospective biomaterial.

Introduction. Perovskite LaFeO₃ is a promising material due to its mixed ionic and electronic conductivity. The classic method for obtaining LaFeO₃ is the solid-phase reaction method, which includes several long cycles of ball milling and high-temperature sintering at 1400 °C. This paper presents the synthesis of LaFeO₃ nanoparticles using lanthanum and iron nitrates at 1200 °C, as well as the structural and photocatalytic properties of the obtained nanoparticles.

Materials and Methods. Perovskite LaFeO₃ nanoparticles were obtained by evaporating an aqueous solution of a mixture of La(NO₃)₃ and Fe(NO₃)₃, followed by annealing for 7 hours at 1200 °C. LaFeO₃ nanoparticles were studied by X-ray diffraction, SEM, EDX, UV-Vis diffuse light scattering, photoluminescence, and FTIR spectroscopy. The photocatalytic activity of LaFeO₃ nanoparticles was evaluated by the photocatalytic degradation of rhodamine B (RhB) solution; active radicals generated during photocatalytic reactions were determined by the "trapping" method.

Results. Nanoparticles of orthorhombic perovskite LaFeO₃ with an average crystallite size of approximately 63 nm were obtained; the band gap of LaFeO₃ nanoparticles was 3.21 eV. According to photoluminescence spectroscopy, LaFeO₃ nanoparticles exhibit low photoluminescence intensity, which indicates a low charge recombination rate. LaFeO₃ nanoparticles exhibit high photocatalytic activity in the UV range (350 nm). At a nanoparticle concentration of 40 mg per 50 ml of RhB solution (10 mg/l), the solution becomes discolored within 90 minutes; the active particles are OH-radicals.

Conclusion. It has been demonstrated that photocatalytically active LaFeO₃ nanoparticles with a size of t approximately 63 nm can be obtained using the nitrate method in one stage within 7 hours at a synthesis temperature of 1200°C. The LaFeO3 nanoparticles obtained using this method have high photocatalytic activity due to the generation of OH radicals upon irradiation with light of a wavelength of 350 nm.

The study was funded by the Russian Science Foundation (25-19-00458-P)