Search Results (8,279)

The activity and stability of Ni-based catalysts for CO₂ methanation strongly depend on the morphology and chemical composition of the support. In this work, Ni catalysts with four oxidic supports (SiO₂, Al₂O₃, CeO₂, ZrO₂) were synthesized via a one-step spray pyrolysis approach. Comprehensive characterization by STEM-EDS, XRD, and N₂ adsorption was used to resolve support morphology, Ni particle size, and nanoparticle incorporation into the support matrix. Beyond steady-state activity and reaction mechanism, the support material also affects the activation period and initial stability of the catalysts. By combining temperature-programmed methanation scans on fresh and spent samples with long-term stability tests, we clearly identify support-dependent changes in initial activity and their correlation with Ni–support interactions. Enhanced physical embedding and stronger chemical binding of Ni nanoparticles significantly reduce activity changes during the first hours on stream. Overall, this study demonstrates that the support and the corresponding metal–support interactions not only affect reaction pathways and activity, but also the pretreatment and activation required to reach a stable operating point, which is of crucial importance in kinetic catalysis research. Full article

The escalating threat of antimicrobial resistance has spurred extensive research into antimicrobial fibers. While numerous reviews have comprehensively cataloged the classification and mechanisms of natural, inorganic, and organic antimicrobial agents, a critical gap remains: few have systematically evaluated the engineering strategies that translate intrinsic biocidal activity into durable, real-world fiber performance. This review addresses this gap by shifting focus from encyclopedic enumeration to a problem-oriented critical assessment of performance optimization strategies. We examine recent advances in natural fibers (bamboo, hemp, chitosan, jute) and synthetic fibers modified with antimicrobial agents, with emphasis on three core challenges—poor wash durability of natural agents, aggregation and leaching of inorganic nanoparticles (e.g., Ag, ZnO, MOFs), and structural limitations of organic agents (e.g., QACs, QPSs, N-halamines, PHMB). Key optimization routes, including covalent grafting, microstructural control (e.g., triaxial microfluidic spinning), organic-inorganic hybridization, and rechargeable N-halamine systems, are critically assessed for their effectiveness in enhancing washing resistance, stability, and antimicrobial synergy. Based on this comparative synthesis, we identify future directions—smart-responsive systems, sustainable processing pathways, and standardized evaluation protocols—to guide the rational design of next-generation high-performance antimicrobial fibers. Full article

Macrophage membrane-coated nanoparticles (MMNPs) are an emerging class of biomimetic nanoplatforms that combine the immune-regulatory functions of macrophages with the structural versatility of synthetic nanoparticles (NPs). By retaining key membrane proteins and receptors, MMNPs exhibit natural targeting capabilities, immune interactions, and inflammatory site homing, making them promising tools for immunomodulation and targeted therapy. This review summarizes macrophage biology relevant to immune regulation and discusses how nanoparticle core properties, including size, surface charge, composition, and mechanical characteristics, influence membrane coating efficiency, stability, and biological performance. Current fabrication and characterization strategies for MMNPs are also discussed. Particular emphasis is placed on the therapeutic applications of MMNPs in inflammatory disorders, tissue regeneration, and oral and dental implant-related applications. Recent studies demonstrate that MMNPs can modulate macrophage polarization, sequester pro-inflammatory cytokines, remodel the immune microenvironment, and promote tissue repair and bone regeneration, highlighting their potential to improve implant integration and reduce inflammation-associated implant failure. Despite these promising advances, challenges remain regarding large-scale manufacturing, membrane preservation, reproducibility, and long-term biosafety. Continued interdisciplinary research in nanotechnology, immunology, and biomaterials engineering is expected to accelerate the clinical translation of MMNPs for regenerative and immunomodulatory therapies. Full article

Nano bioinks have recently emerged as a promising class of biomaterials for advanced bioprinting applications, offering new opportunities in regenerative medicine, controlled drug delivery, and biosensing technologies. These materials are typically developed by integrating nanostructures such as nanoparticles, nanosheets, and nanofibers into polymeric or hydrogel matrices to enhance mechanical strength, bioactivity, and printing performance. Various fabrication approaches such as direct blending, in-situ polymerization, and surface functionalization are used to incorporate nanomaterials into bioink formulations. Subsequent crosslinking strategies are employed to improve print fidelity and structural stability while maintaining cell viability and biological functionality during the bioprinting process. Despite significant progress in recent years, several challenges continue to hinder the clinical translation of nano bioinks. Achieving consistent batch-to-batch reproducibility, ensuring long-term biocompatibility, and optimizing rheological properties for reliable printing remain critical issues. In addition, regulatory pathways and ethical considerations related to the biomedical use of nano-enabled bioinks are still insufficiently addressed in the literature. This review provides a comprehensive overview of recent advances in the design and fabrication of nano bioinks, highlighting key synthesis strategies, functional nanomaterials used in bioink formulations, and their emerging applications in tissue engineering, drug delivery, and biosensing. Furthermore, the review discusses the major technical, regulatory, and translational challenges that need to be addressed to facilitate the safe and effective implementation of nano bioinks in future biomedical applications. Full article

Protein crystal nucleation remains difficult to predict and control and is still a critical issue in structural biology, protein crystal formulations, and crystal engineering. Heterogeneous nucleants can regulate protein crystallization by providing solid interfaces, enriching protein molecules, and stabilizing prenucleation aggregates; however, their dominant action stage, particle-size effect, and interfacial interaction mechanism remain unclear. In this study, hen egg white lysozyme (HEWL) was selected as a model protein, and silica nanoparticles (SNPs) with average diameters of 80, 120, and 200 nm were prepared using the modified Stöber method. Under a constant total particle surface area, the effects of SNPs on HEWL crystallization, prenucleation aggregation, interfacial adsorption, and subsequent crystal growth were systematically investigated. The results showed that, under 30 mg·mL⁻¹ HEWL and 0.6 M NaCl conditions, all SNPs shortened the apparent induction time, with 200 nm SNPs showing the strongest effect. In contrast, 80 nm SNPs produced the largest crystal size at the fixed observation time of 72 h, suggesting that crystal size within a fixed incubation period is jointly affected by nucleation rate, nucleus number, local solute consumption, and subsequent crystal growth. Under low protein concentration and low NaCl concentration conditions, SNPs promoted crystal formation in systems with weak spontaneous nucleation. Zeta potential, UV-Vis, fluorescence, FT-IR, CD, and DLS results suggested that SNPs interacted with HEWL at the interface and promoted apparent aggregation behavior, whereas polarized optical microscopy indicated no detectable influence on the later linear growth of visible crystals. These results suggest that SNPs mainly affect processes before visible crystal formation and provide insight into their application as heterogeneous nucleants for protein crystallization. Full article

Glutathione (GSH)-responsive nanozymes have attracted increasing attention for biosensing and cancer therapy. However, their practical applications are often limited by aggregation and insufficient catalytic activity. Herein, we report a zwitterionic sulfobetaine-modified palladium nanozyme (SH-SB/Pd NPs) that addresses these limitations by integrating high catalytic activity. The zwitterionic ligand simultaneously stabilizes Pd nanoparticles and preserves accessible catalytic sites, resulting in markedly enhanced peroxidase-like activity. SH-SB/Pd NPs efficiently catalyze H₂O₂ decomposition to generate multiple reactive oxygen species (¹O₂, O₂^•− and •OH), enabling favorable affinity for TMB (K_m(TMB) = 0.28) and sensitive colorimetric GSH detection with a low detection limit of 0.135 μM. Benefiting from their long-term antifouling properties and ROS-generating capability, SH-SB/Pd NPs also exhibit potent antitumor activity, achieving 76.56% inhibition of HeLa cells under 808 nm laser irradiation. This work establishes a zwitterionic nanozyme platform that improves catalytic activity, stability, and therapeutic performance, offering a promising strategy for biosensing and synergistic cancer therapy. Full article

We present cystamine-modified polydopamine (PDA) coatings as tunable gatekeepers for mesoporous silica nanoparticles (MSNs) in drug delivery. Unlike conventional post-functionalization strategies, cystamine moieties were incorporated directly into the PDA network, enabling tunable shell composition and redox responsiveness by simply adjusting the dopamine-to-cystamine ratio. By varying the cystamine:dopamine ratio, pH- and redox-responsive release of doxorubicin (DOX) and sorafenib (SO) was achieved, with release kinetics following the Higuchi model. Cystamine-modified PDA nanoparticles with varying disulfide bridge content were synthesized and comprehensively characterized using SEM, TGA, FTIR, and zeta potential measurements. The cystamine content was found to influence thermal stability, coating performance, and protective properties. Importantly, increasing disulfide content did not necessarily improve release performance, suggesting that excessive crosslinking may partially restrict shell permeabilization and drug diffusion. These findings reveal important structure–property relationships in catechol-based coatings and underline the significance of disulfide linkages in the design of bioinspired stimuli-responsive drug delivery systems. Full article

The presence of aflatoxin B1 (AFB1) is ubiquitous in the environment, and it is considered one of the most powerful natural carcinogenic substances. In this study, a highly sensitive electrochemical aptasensor was designed to detect aflatoxin B1 (AFB1) in peanuts. Iron–cobalt-doped magnetic carbon (Fe-Co/NPC) was used to enhance the conductivity of the electrode and catalytic performance, providing an increased specific surface area. Gold nanoparticles (AuNPs) were used to immobilize an aptamer. And cDNA-polyacrylic acid (cDNA-PAA) nanogels served as a high-density carrier for cDNA and an active signal amplification unit, significantly increasing the charge transfer resistance (Rct) through steric hindrance and electrostatic repulsion. Unlike traditional aptasensors that relied on passive blocking agents, we designed a competitive displacement mechanism. AFB1 competed with cDNA-PAA during detection in order to bind to the aptamer, which resulted in the removal of the non-conductive complex and a substantial increase in the electrochemical signal. Under the optimal conditions, the aptasensor had a linear response range of 1–1000 ng/L and a limit of detection (LOD) of 0.3 ng/L. It displayed high specificity, reproducibility, and stability. In spiked peanut samples, the recoveries ranged from 98.04% to 100.86%. Due to its sensitivity and reliability, this aptasensor has a great determination of AFB1 in food safety applications. Full article

The skin is the largest organ of the human body and acts as a major protective barrier against external agents. However, the highly organized stratum corneum limits the effective delivery of many therapeutic compounds, especially hydrophilic and high-molecular-weight drugs. Conventional topical formulations often exhibit poor permeability, low bioavailability, and limited targeting efficiency. This review discusses recent advances in nanotechnology-based drug delivery systems, including bio-based, biodegradable, and biocompatible polymeric nanocarriers for dermal and transdermal applications, with particular emphasis on vesicular, polymeric, and hybrid nanosystems. Nanocarriers such as liposomes, ethosomes, transfersomes, polymeric nanoparticles, micelles, nanogels, and lipid–polymer hybrid systems have demonstrated improved drug solubility, stability, controlled release, and skin permeation for localized (dermal) delivery compared with conventional formulations. In addition, biodegradable polymeric materials enhance dermal deposition and prolong drug retention, leading to improved therapeutic efficacy. These nanosystems can facilitate enhanced transdermal drug transport under optimized conditions; however, the extent of systemic delivery varies widely depending on drug physicochemical properties, formulation characteristics, and application conditions. Drug transport may occur through intercellular, transcellular, and follicular pathways, resulting in enhanced bioavailability and site-specific delivery. Claims regarding transdermal (systemic) absorption are restricted to cases supported by in vivo or clinical evidence. Furthermore, combining nanocarriers with microneedles and stimuli-responsive platforms has expanded the potential for controlled and on-demand transdermal delivery. Recent preclinical and clinical studies have reported that nanocarrier-based methotrexate gels reduced PASI-like scores by over 70% in psoriatic models, while oleic acid vesicle formulations achieved more than 95% cure rates in rodent models of tinea corporis. Despite these advances, challenges related to large-scale production, stability, regulatory approval, and clinical translation remain significant. Future developments integrating smart nanocarriers, bio-based polymeric biomaterials, wearable technologies, and AI-assisted design may improve personalized dermatological therapies. These innovations in nanocarrier drug delivery are accelerating the translation of advanced therapies to the clinic, promising safer, more effective and personalized dermatological treatments. Full article

In this study, green-synthesized silver nanoparticles derived from Zingiber officinale (G-AgNPs) were investigated as potential modulators of transmembrane serine protease 2 (TMPRSS2), a host-associated protease involved in viral entry mechanisms. Before nanoparticle synthesis, the phytochemical composition of ginger extract was analyzed using high-performance liquid chromatography (HPLC) with photodiode array detection. Silver nanoparticles were synthesized using aqueous ginger extract as a reducing and stabilizing agent. The nanoparticles were characterized by ultraviolet–visible spectroscopy (UV–Vis.), Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), zeta potential analysis, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The synthesized silver nanoparticles exhibited a face-centered cubic (fcc) crystalline structure, nanoscale particle size distribution, and moderate colloidal stability. Transmission electron microscopy revealed predominantly quasi-spherical nanoparticles with an average diameter of 10.61 ± 1.31 nm, while X-ray diffraction indicated an average crystallite size of 15.28 ± 5.48 nm. Biological evaluation demonstrated robust, broad-spectrum antibacterial activity against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, with distinct susceptibility profiles. Minimum Inhibitory Concentration (MIC) values were 3.125 µg/mL and 12.5 µg/mL, and Minimum Bactericidal Concentration (MBC) values were 6.25 µg/mL and 25.0 µg/mL, respectively. Cell culture assays confirmed high cytocompatibility with L929 fibroblasts at all tested concentrations. In a fluorometric enzyme assay, the silver nanoparticles inhibited TMPRSS2 activity in a concentration-dependent manner, achieving 51.24% inhibition at 100 µg/mL and an estimated IC50 of 40.06 µg/mL. Although the inhibitory activity was lower than that of Camostat, the findings suggest that ginger-mediated silver nanoparticles represent promising plant-based nano-bioactive systems for further investigation of TMPRSS2 modulation. Full article

Background: Actinium-225 (²²⁵Ac) is receiving major attention as the radionuclide of choice for targeted alpha therapy (TAT) due to its outstanding physical properties such as a long physical half-life of 9.9 days and a short range of alpha (α)-particles which are responsible for the destruction of malignant tumors, whilst sparing normal surrounding tissues. Although the physical properties of ²²⁵Ac make it a desirable radionuclide for TAT, its application is challenging due to the lack of chelators available to stabilize its daughter radionuclides, resulting in the recoil effect. This occurs when there is a breakdown between the radionuclide and the chelator, therefore minimizing the therapeutic effects of the radiopharmaceutical. Nanodrug delivery systems (NDDSs) may minimize the challenge of ²²⁵Ac’s recoiling daughters and increase tumor penetration. Aim: This study aimed at using poly(lactic-co-glycolic)acid (PLGA) and chitosan (CS) nanoparticles as a delivery vehicle for targeted alpha therapy of prostate cancer in order to increase the therapeutic effect of ²²⁵Ac PSMA617-TFA. Methods and Results: PLGA nanoparticles were prepared using a nanoprecipitation method, after which they were functionalized with chitosan and folic acid. Following synthesis of ²²⁵Ac PSMA617-TFA, the radiopharmaceutical was loaded onto the nanoparticles. SEM analysis and FTIR were performed for characterization of the nanoparticles, and in-vitro drug release of ²²⁵Ac PSMA617-TFA at pH = 6.5 and pH = 7.4, respectively, was measured. The nanoparticles prepared had an average size of 200 nm and had a positive charge. This was further confirmed using a zetasizer and with scanning electron microscope (SEM) analysis. The PLGA-CS nanoparticles indicated a high encapsulation efficiency after 24 h. The results also showed a controlled release of ²²⁵Ac PSMA617-TFA over 72 h. The results of this study indicate that PLGA-CS nanoparticles are suitable for retaining ²²⁵Ac and its recoiling daughters (²²¹Fr and ²¹³Bi) at the tumor site, potentially providing a platform for future therapeutic evaluation. Conclusions: The results of this study indicate that PLGA-CS nanoparticles demonstrate feasibility as a drug delivery vehicle for ²²⁵Ac PSMA617-TFA, with effective retention of ²²⁵Ac and its decay daughters. However, biological validation through in vitro cellular studies and in vivo preclinical models is required before therapeutic effectiveness can be established. Full article

This work describes an efficient and environmentally friendly method for the synthesis of silver-based nanostructures through a green route using Aloe vera extract as a reducing agent, silver nitrate (AgNO₃) as a precursor, and polyvinylpyrrolidone (PVP, 10 kDa molecular weight) as a stabilizing agent. The formation of these structures was supported by UV–Vis spectroscopy, where a surface plasmon resonance (SPR) band was observed between 425 and 460 nm. Scanning electron microscopy revealed predominantly spherical features in the 300–500 nm range; however, the distinction between primary nanoparticles and aggregates cannot be conclusively established from SEM alone. EDX analysis indicated a silver content of 59.96 wt%. Antibacterial assays performed in Z8 medium demonstrated a reduction in cyanobacterial growth with increasing dosage, with complete inhibition observed at ≥20 $\mu$L (nominal MIC = 1.77 mg mL⁻¹, based on precursor estimation). Total dissolved solids and absorbance measurements exhibited a decreasing trend with increasing concentration (effect size = 0.87, $p<0.001$), supporting an inhibitory effect under the tested conditions. These findings suggest potential antibacterial activity. However, this study should be considered exploratory, and further work is required to elucidate the underlying mechanisms. Full article

This review covers literature published up to June 2026. Detecting various water pollutants quickly and reliably remains a challenge. Boron-doped diamond (BDD) electrodes, particularly when fabricated as nanostructured thin films such as nanocones or nanowalls, offer a wide electrochemical window, low background current, and excellent chemical stability, making them promising tools for electrochemical sensing. However, unmodified BDD electrodes face an inherent trade-off among conductivity, active site density, and interfacial stability, a phenomenon termed herein the “sensitivity-selectivity-stability triangle bottleneck”, which severely limits practical performance. In this review, we demonstrate how multi-scale structural regulation can circumvent this bottleneck. Specifically, a triple strategy comprising boron doping, surface modification, and post-annealing treatment is proposed and evaluated. First, the effect of boron doping level on conductivity and active site density is discussed. Second, two common surface modification approaches are examined: carbon nanomaterials (which increase surface area and form conductive networks) and metal nanoparticles (which enhance catalytic activity and interfacial charge transfer). Third, post-annealing is highlighted as a key synergistic step that locks the modified layer and stabilizes the interface. Together, these three components form an integrated framework. To provide concrete guidance, the performance of each strategy is compared for representative water pollutants, including heavy metal ions, phenolic compounds, and emerging contaminants such as antibiotics and pesticides, with emphasis on sensitivity, selectivity, and stability. Representative detection limits achieved include 0.01 μg/L for Pb²⁺, 5 nM for acetaminophen, and 0.32 fM for PCB-77, demonstrating the effectiveness of the triple structural regulation strategy. Finally, in line with the theme of this Nanomaterials Special Issue on nanostructured thin films, current challenges in structural regulation are summarized, and future directions, including multi-parameter optimization, AI-assisted high-throughput screening, and real-world testing, are outlined. The goal is to offer practical structure-performance guidelines for designing BDD-based electrochemical sensors that are both high-performing and durable. Full article

Chlorophyll, a natural photosynthetic pigment, is gaining interest for its sustainable and eco-friendly applications in renewable energy, particularly as a photosensitizer in dye-sensitized solar cells (DSSCs). This study investigates the feasibility of chlorophyll extracted from Moringa oleifera as a natural photosensitizer in DSSCs, building on our previous work demonstrating its high chlorophyll content and long-term stability. Chlorophyll was extracted using acetone under optimal conditions (45 °C, 60 min) and applied in DSSCs comprising a TiO₂ photoanode, iodide/triiodide electrolyte, and platinum counter electrode. The TiO₂ photoanode was characterised using UV-Vis spectroscopy, FE-SEM, XRD, and Raman spectroscopy, confirming the presence of pure anatase phase TiO₂ with uniform spherical nanoparticle morphology. The fabricated DSSCs achieved a short-circuit current density of 0.197 mA cm⁻², an open-circuit voltage of 0.44 V, a fill factor of 32%, and a photoconversion efficiency (PCE) of 0.027%. While this performance is lower than the highest reported chlorophyll-based DSSC efficiency (4.6%), the results demonstrate that M. oleifera is a viable and sustainable source of chlorophyll for DSSC applications. The findings highlight the importance of dye–semiconductor interactions and suggest that further optimisation through co-sensitization, TiO₂ surface modification, and improved dye anchoring could enhance device performance. Full article

Freshwater contamination by phosphate and pathogenic bacteria requires low-cost multifunctional treatment materials. Unlike previous studies that use a single biogenic agent to synthesize a single nanoparticle type, this work uses one fixed Aloe vera extraction protocol to generate three chemically distinct nanoparticles (Ag, CuO, Fe₃O₄) on the same waste-derived carbon support, enabling a direct, extract-controlled comparison of nanoparticle identity on water-treatment performance. Activated carbon (AC) was prepared from waste wattle bark (Acacia mearnsii) by steam activation at 700 °C and functionalized with biogenically synthesized Ag, CuO, and Fe₃O₄ nanoparticles (NPs) using Aloe vera extract as a reducing and stabilizing agent. Average nanoparticle sizes were 43 nm for Ag, 59 nm for CuO, and 13 nm for Fe₃O₄. FTIR, PXRD, SEM-EDS, TEM, DLS, TGA, and BET analysis characterized the materials. Among the composites, Fe₃O₄NPs/AC showed the best phosphate removal performance, achieving 93% removal and a maximum adsorption capacity of 9.3 mg/g under acidic conditions, compared with 3.3 mg/g for pristine AC. Equilibrium data were better described by the Freundlich model (R² = 0.999), indicating adsorption on a heterogeneous surface. Ag NPs/AC exhibited complete inactivation of both Escherichia coli and Staphylococcus aureus within 2 h, while CuO NPs/AC (a more economical alternative) achieved near-complete inactivation of both bacteria within 6 h. AC from spent wattle bark and functionalized with green-synthesized nanoparticles is thus a promising platform for combined phosphate removal and antibacterial water treatment. Consistent with their respective roles, Fe₃O₄ NPs/AC was evaluated exclusively for phosphate adsorption, while Ag NPs/AC and CuO NPs/AC were evaluated exclusively for antibacterial activity; no single composite was tested for both functions. Full article