Journal of Applied Electrochemistry

Metasurfaces, composed of engineered nanoantennas, enable unprecedented control over electromagnetic waves by leveraging multipolar resonances to tailor light–matter interactions. This review explores key physical mechanisms that govern their optical properties, including the role of multipolar resonances in shaping metasurface responses, the emergence of bound states in the continuum (BICs) that support high-quality factor modes, and the Purcell effect, which enhances spontaneous emission rates at the nanoscale. These effects collectively underpin the design of advanced photonic devices with tailored spectral, angular, and polarization-dependent properties. This review discusses recent advances in metasurfaces and applications based on them, highlighting research that employs full-wave numerical simulations, analytical and semi-analytic techniques, multipolar decomposition, nanofabrication, and experimental characterization to explore the interplay of multipolar resonances, bound and quasi-bound states, and enhanced light–matter interactions. A particular focus is given to metasurface-enhanced photodetectors, where structured nanoantennas improve light absorption, spectral selectivity, and quantum efficiency. By integrating metasurfaces with conventional photodetector architectures, it is possible to enhance responsivity, engineer photocarrier generation rates, and even enable functionalities such as polarization-sensitive detection. The interplay between multipolar resonances, BICs, and emission control mechanisms provides a unified framework for designing next-generation optoelectronic devices. This review consolidates recent progress in these areas, emphasizing the potential of metasurface-based approaches for high-performance sensing, imaging, and energy-harvesting applications.

The colloidal long-storage stability of nanosized drugs is a crucial factor for pharmacology, as they require much time for robust estimation. The application of bioavailable magnetic nanosuspensions in theranostics is limited by incomplete information about their colloidal stability in the internal media of human organisms. A method for the accelerated temperature stress “aging” of magnetic nanosized suspensions is proposed for the rapid assessment and prediction of the colloidal stability over time of nanosized iron oxide suspensions stabilized by albumin HSA. Colloidal stability is assessed using dynamic light scattering (DLS), fluorescence spectroscopy, electrophoresis, and ion monitoring methods during short- and long-term storage. Rapid assessment is achieved by short high-temperature (70 °C) processing of carboxymethyl-dextran-coated nanosol in the presence of albumin. The role of albumin in the sustained stability of superparamagnetic iron oxide particles (SPIONs) was studied under conditions mimicking blood plasma (pH = 7.4) and endolysosomal cell compartments (pH = 5.5). According to the fluorescence quenching and DLS data, colloidal stability is ensured by the formation of an HSA corona on carboxymethyl-dextran-coated SPIONs and their process of clustering. In the presence of albumin, the colloidal stability of nanoparticles is shown to increase from 80 to 121 days at a storage temperature of 8 °C The prognostic shelf life of magnetic nanosol is estimated by calculating the Van’t Hoff’s relation for the rate of chemical reactions. The validity of using the Van’t Hoff’s rule is confirmed by the agreement of the calculated activation energy at 8 °C and 70 °C. The developed method of the accelerated aging of nanoparticles can not only be employed for the estimation of the shelf life of magnetic nanoparticles coated with HSA in vitro but also for assessing the stability of SPIONs applied in vivo.

In this study, we present atomic layer deposition (ALD) of nickel oxides (NiOx) using a new nickel precursor, (methylcyclopentadienyl)(cyclopentadienyl)nickel (NiCp(MeCp)), and ozone (O3) as the oxygen source. The process features a relatively short saturation pulse of the precursor (NiCp(MeCp)) and a broad temperature window (150–250 °C) with a consistent growth rate of 0.39 Å per cycle. The NiOx film deposited at 250 °C primarily exhibits a polycrystalline cubic phase with minimal carbon contamination. Notably, the post-annealed ALD NiOx film demonstrates attractive electrocatalytic performance on the oxygen evolution reaction (OER) by providing a low overpotential of 320 mV at 10 mA cm−2, a low Tafel slope of 70.5 mV dec−1, and sufficient catalytic stability. These results highlight the potential of the ALD process using the NiCp(MeCp) precursor for the fabrication of high-activity catalysts.

Periodontitis is a widespread disease, associated with challenges both in its diagnosis and in selecting from various therapeutic approaches, which do not always yield the expected success. This literature review was conducted to explore diverse therapeutic approaches, especially those focused on nanotechnologies, and their potential contribution to the successful modulation of the host’s response. The effects of the existing microbial diversity and the imbalance of key microbial species in contributing to the progression and worsening of the host’s response in periodontitis are well known. It is essential to understand the role of a well-structured treatment plan for periodontitis, providing opportunities for new research and innovative treatment strategies aimed at reducing the impact of periodontitis on oral and overall systemic health. This will be beneficial for dental professionals, enabling them to effectively prevent and treat periodontitis, ultimately improving the overall health and well-being of patients.

This study addresses the challenge of the scalable, cost-effective synthesis of high-quality turbostratic graphene from low-cost carbon sources, including biomass waste such as sugarcane leaves, bagasse, corncobs, and palm bunches, using the Direct Current Long Pulse Joule Heating (DC-LPJH) technique. By optimizing the carbonization process and blending biomass-derived carbon with carbon black and turbostratic graphene, the gram-scale production of turbostratic graphene was achieved in just a few seconds. The synthesis process involved applying an 18 kJ electrical energy pulse for 1.5 s, resulting in temperatures of approximately 3000 K that facilitated the transformation of the carbon atoms into well-ordered turbostratic graphene. Structural and morphological characterization via Raman spectroscopy revealed low-intensity or absent D bands, with a high I2D/IG ratio (~0.8–1.2), indicating monolayer turbostratic graphene formation. X-ray photoelectron spectroscopy (XPS) identified sp2-hybridized carbon and oxygenated functional groups, while NEXAFS spectroscopy confirmed the presence of graphitic features and both sp2 and sp3 bonding states. Energy consumption calculations for the DC-LPJH process demonstrated approximately 10 kJ per gram, demonstrating the potential for cost-effective production. This work presents an efficient approach for producing high-quality turbostratic graphene from low-cost carbon sources, with applications in enhancing the properties of composites, polymers, and building materials.

The electrochemical carbon dioxide reduction reaction (CO2RR) represents a promising approach for achieving CO2 resource utilization. Carbon-based materials featuring single-atom transition metal-nitrogen coordination (M-Nx) have attracted considerable research attention due to their ability to maximize catalytic efficiency while minimizing metal atom usage. However, conventional synthesis methods often encounter challenges with metal particle agglomeration. In this study, we developed a Ni-doped polyvinylidene fluoride (PVDF) fiber membrane via electrospinning, subsequently transformed into a nitrogen-doped three-dimensional self-supporting single-atom Ni catalyst (Ni-N-CF) through controlled carbonization. PVDF was partially defluorinated and crosslinked, and the single carbon chain is changed into a reticulated structure, which ensured that the structure did not collapse during carbonization and effectively solved the problem of runaway M-Nx composite in the high-temperature pyrolysis process. Grounded in X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS), nitrogen coordinates with nickel atoms to form a Ni-N structure, which keeps nickel in a low oxidation state, thereby facilitating CO2RR. When applied to CO2RR, the Ni-N-CF catalyst demonstrated exceptional CO selectivity with a Faradaic efficiency (FE) of 92%. The unique self-supporting architecture effectively addressed traditional electrode instability issues caused by catalyst detachment. These results indicate that by tuning the local coordination structure of atomically dispersed Ni, the original inert reaction sites can be activated into efficient catalytic centers. This work can provide a new strategy for designing high-performance single-atom catalysts and structurally stable electrodes.

Recently, various biocompatible and biodegradable materials have garnered significant attention as cosmetic fillers for skin rejuvenation. Among these, poly ε-caprolactone (PCL), poly L-lactic acid (PLLA), poly D,L-lactic acid (PDLLA), and polydioxanone (PDO) microspheres have been developed and commercialized as a dermal filler. However, its irregularly hydrophobic microspheres pose hydration challenges, often causing syringe needle blockages and side effects such as delayed onset nodules and papules after the procedure. In this study, we synthesized a polyethylene glycol-poly D,L-lactic acid (mPEG-PDLLA) copolymer to address the limitations of conventional polymer fillers. Comprehensive characterization of the copolymer was performed using nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and differential scanning calorimetry. The mPEG-PDLLA copolymers demonstrated a unimodal size distribution of approximately 121 ± 20 nm in an aqueous solution. The in vitro cytotoxicity and collagen genesis of mPEG-PDLLA copolymers were evaluated using human dermal fibroblast cells. In this study, angiogenesis was observed over time in hairless mice injected with mPEG-PDLLA copolymers, confirming its potential role in enhancing collagen synthesis. To assess the inflammatory response, the expression levels of the genes MMP1 and IL-1β were analyzed. Additionally, gene expression levels such as transforming growth factor-β and collagen types I and III were compared with Rejuran® in animal studies. The newly developed collagen-stimulating PEGylated PDLLA may be a safe and effective option for skin rejuvenation.

Organic pollutants present a substantial risk to both ecological systems and human well-being. Activation of peroxymonosulfate (PMS) have emerged as an effective strategy for the degradation of organic pollutants. Bi-based heterojunction is commonly used as a photocatalyst for reductively activating PMS, but single-component Bi-based heterojunction frequently underperforms due to its restricted absorption spectrum and rapid combination of photogenerated electron–hole pairs. Herein, BiVO4 was selected as the oxidative semiconductor to form an S-type heterojunction with CuBi2O4—x-CuBi2O4/BiVO4 (x = 0.2, 0.5, and 0.8) for PMS photoactivation. The built-in electric field (BEF) in x-CuBi2O4/BiVO4 promoted electron transfer to effectively activate PMS. The x-CuBi2O4/BiVO4 heterojunctions also demonstrate stronger adsorption of the polar PMS than pure CuBi2O4 or BiVO4. In addition, the BEF prompts photoelectrons able to reduce O2 to •O2− and photogenerated holes in the valence band of BiVO4 able to oxidize H2O to generate •OH. Therefore, under visible light irradiation, 95.1% of ciprofloxacin (CIP) can be degraded. The 0.5-CuBi2O4/BiVO4 demonstrated the best degradation efficiency and excellent stability in cyclic tests, as well as a broad applicability in degrading other common pollutants. The present work demonstrates the high-efficiency S-type heterojunctions in the coupled photocatalytic and PMS activation technology.

Copper (II) oxide nanoparticles (CuO NPs) attract much attention as a promising antimicrobial agent. We studied the antibacterial properties of three types of CuO NPs against Escherichia coli bacteria: flake-shaped particles with a diameter of 50–200 nm and a thickness of 10–20 nm (CuO-CD synthesized by chemical deposition), spherical particles with a size of 20–90 nm (CuO-EE obtained by electrical explosion), and rod-shaped particles with a length of 100–200 nm and a diameter of 30 × 70 nm (CuO-CS commercial sample). We tested how the shape, size, and concentration of the NPs, and composition of the dispersion medium affected the properties of the CuO NPs. We prepared dispersions based on distilled water, a 0.9% NaCl solution, and the LB broth by Lennox and used Triton X-100 and sodium dodecyl sulfate (SDS) as stabilizers. The concentration of NPs was 1–100 mg L−1. We showed that the dispersion medium composition and stabilizer type had the greatest influence on the antibacterial effects of CuO NPs. We observed the maximum antibacterial effect for all CuO NP types dispersed in water without a stabilizer, as well as in LB broth with the SDS stabilizer. The maximum inhibition of culture growth was observed under the influence of CuO-EE (by 30%) and in the LB broth with the SDS stabilizer (by 1.3–1.8 times depending on the type of particles). In the saline solution, the antibacterial effects were minimal; in some cases, the CuO NPs even promoted bacterial culture growth. SDS increased the antibacterial effects of NPs in broth and saline but decreased them in water. Finally, among the particle types, CuO-CS turned out to be the most bactericidal, which is probably due to their rod-shaped morphology and small diameter. At the same time, the concentration and aggregation effects of CuO NPs in the colloidal systems we studied did not have a linear action on their antibacterial properties. These results can be used in the development of antibacterial coatings and preparations based on CuO NPs to achieve their maximum efficiency, taking into account the expected conditions of their use.

Nanostructured materials have garnered significant attention for their unique properties, such as the high surface area and enhanced reactivity, making them ideal for electrocatalysis. Among these, perovskite oxides, with compositional and structural flexibility, stand out for their remarkable catalytic performance in energy conversion and storage technologies. Their diverse composition and tunable electronic structures make them promising candidates for key electrochemical reactions, including the oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and carbon dioxide reduction (CO2RR). Nanostructured perovskites offer advantages such as high intrinsic activity and enhanced mass/charge transport, which are crucial for improving electrocatalytic performance. In view of the rapid development of nanostructured perovskites over past few decades, this review aims to provide a detailed evaluation of their synthesis methods, including the templating (soft, hard, colloidal), hydrothermal treatments, electrospinning, and deposition approaches. In addition, in-depth evaluations of the fundamentals, synthetic strategies, and applications of nanostructured perovskite oxides for OER, HER, and CO2RR are highlighted. While progress has been made, further research is needed to expand the synthetic methods to create more complex perovskite structures and improve the mass-specific activity and stability. This review offers insights into the potential of nanostructured perovskite oxides in electrocatalysis and provides potential perspectives for the ongoing research endeavor on the nanostructural engineering of perovskites.

Microplastics (MPs) and antibiotics are widely detected in water bodies. However, the adsorption behavior and mechanism of different particle size polystyrene (PS) MPs on macrolide antibiotics under natural aging remain to be elucidated. In this study, potassium persulfate (K2S2O8) was used to simulate the natural aging process of PS MPs. The adsorption behavior and mechanism of different size PS (80 and 400 μm) toward azithromycin (AZI), clarithromycin (CLA), and erythromycin (ERY) were investigated. Results of SEM showed that the surface roughness of aged PS MPs increased with the appearance of cracks, pits, and pores. XPS and FTIR analyses showed enhanced C=O functional groups in the aging process. The adsorption isotherm models revealed that the aging processes enhanced the AZI, CLA, and ERY adsorption tendency, as evidenced by the highest adsorption capacity for aged-80 μm (645, 665, 184 mg/kg) > original-80 μm (412, 420, 120 mg/kg), and aged-400 μm (280, 330, 110 mg/kg) > original-400 μm (197, 308, 100 mg/kg). Kinetic model fitting revealed that the adsorption process occurred in three stages: rapid, slow, and saturation. Adsorption kinetic curves for original and aged PS MPs conformed to the pseudo-second-order kinetic model. In contrast, the adsorption isotherm data fit the Langmuir model, indicating that the process primarily involved uniform monolayer chemical adsorption. Our findings provide insights into the substantial changes in the interactions between PS and macrolide antibiotics with aging processes.

A multi-vane and multi-slit electrospinning nozzle for diversion was proposed to respond to the issues of easiness of clogging, existing End Effect among needles in current multi-needle electrospinning, and uncontrollable Taylor cone position in needleless electrospinning. The upper part of the novel nozzle is a cylindrical straight pipe, and the lower part is a flow channel expansion structure composed of multiple vane components that spread outward at an angle. Ansys software was used to study the effect of different opening angles of the vanes on the spreading of the electrospinning solution. In the fluid simulation, for the novel nozzle with a central slit and a support structure, when the vanes have an opening angle of 35° and a length of 11 mm, the droplet holding time is 16 s, twice as long as the nozzle without support (8 s). This result corresponds to the subsequent droplet holding experiment, showing that the support structure aids droplet holding and enhances electrospinning stability. Comsol Multiphysics software was used to investigate the effect of the vanes’ parameters on the uniformity of the electric field. The results indicate that when the vanes of the new electrospinning nozzle are set at an opening angle of 35°, with four vanes each 11 mm in length, a receiving distance of 200 mm, and a voltage of 30 kV, the novel nozzle achieves an average electric field intensity of 5.26 × 10⁶ V/m with a CV value of 6.93%. Metal 3D printing was used to create a new nozzle for electrospinning, which successfully produced stable multiple jets and increased nanofiber output.

Based on modern concepts of the nonlinear percolation mechanisms of electrical and magnetic properties in granular metal–dielectric nanocomposites, the authors present for the first time a comparative analysis of their own results of a comprehensive study of nonlinear electromagnetic properties in two nanocomposite systems: metal–dielectric Cox(MgF2)100−x and alloy–dielectric (CoFeZr)x(MgF2)100−x, obtained by ion-beam sputtering of composite targets in a wide range of different compositions. For the first time, the features of the influence of atomic composition and structural-phase transitions on nonlinear magnetoresistive, magnetic, and magneto-optical properties in two systems are presented in comparison, one of which, Cox(MgF2)100−x, showed soft magnetic properties, and the second, (CoFeZr)x(MgF2)100−x, hard magnetic properties, during the transition from the superparamagnetic to the ferromagnetic state. Moreover, for the first time, the concentration dependences of the oscillating fine structure of XANES K-absorption edges of Co atoms in the first system and Co and Fe atoms in the second system are presented, which undergo changes at the percolation thresholds in each of the two systems and thus confirm the nonlinear nature of the electromagnetic properties changes in each of the two systems at the atomic level.

Gas hydrate systems display complex structural arrangements in their bulk and interfacial configurations. Controlling nucleation and growth in the context of potential applications requires a characterization of these structures such that they can be manipulated at the atomic and molecular scale to fine tune macroscale applications. This work uses molecular dynamics to show the different methods of identifying interface location and thickness, the drawbacks of certain methods, and proposes improved methodology to overcome sampling issues. We characterize the interfacial position and thickness using structure and dipole-based methods at different conditions for water/sII natural gas hydrate mixtures. We find that phases with similar densities are particularly sensitive to the regression technique employed and may not resolve the thickness of the complex pre-melting layer adequately, while the dipole moments may provide better resolution. The dipole shows the complex natural of the small and compressed layer that presents on the hydrate surface. These results show that the interface is thin but dynamic and careful characterization required analysis of multiple molecular phenomena.

A critical knowledge gap currently exists regarding the potential risks of exposure to nanoplastics (NPs), particularly early in life during key stages of growth and development. Globally abundant plastics, polyamide (nylon) and polystyrene (PS), exist in various products and have been detected in food and beverages as small-scale plastics. In this study, we evaluated how early-life exposure to NPs affects key biological metrics in rat pups. Male and female animals received an oral dose (20 mg/kg/day) of nylon-11 NPs (114 ± 2 nm) or PS NPs (85 ± 1 nm) between postnatal day (PND) 7 and 10. The results showed slight differences in the ratio of liver weight to body weight for male rat pups exposed to PS NPs. Cardiac performance and levels of neurotransmitters and related metabolites in brain tissue showed no differences between animals exposed to NPs and controls. The endogenous metabolite profile in plasma was altered by oral administration of NPs, suggesting perturbation of metabolic pathways involved in amino acid and lipid metabolism. This study explored the biological impacts of oral NP exposure early in life, supporting the need for continued investigations into the potential health effects from exposure to NPs.