Search Results (4,097)

Galls of the Cynipidae, such as the Knopper gall, are abnormal plant outgrowths induced by insect activity. These structures not only protect the developing larvae but also alter the biochemical properties of host plant tissues. In this study, we report the green synthesis of silver nanoparticles (AgNPs) using ethanolic extracts of Quercus robur Knopper galls. AgNPs were synthesized via reduction of AgNO₃ and characterized using ATR-FTIR analysis, UV-Vis spectrophotometry, powder X-ray diffraction (PXRD), and transmission electron microscopy (TEM). The UV-Vis analysis showed a strong surface plasmon resonance (SPR) peak at 418 nm. A face-centered cubic (fcc) crystalline structure with an average crystallite size of about 12 nm was verified by PXRD patterns. TEM imaging revealed well-dispersed spherical nanoparticles, consistent with the size obtained via PXRD. ATR-FTIR analysis indicated the involvement of polyphenolic and protein-related functional groups in reduction and stabilization. The synthesized AgNPs exhibited strong growth inhibition capacity against B. subtilis and S. aureus, and moderate capacity against E. coli and P. aeruginosa. These findings highlight the potential of Knopper gall extract as a sustainable source for the eco-friendly synthesis of biologically active nanoparticles. Full article

Thallium is a soft metal with a grey or silvery hue. It commonly occurs in two oxidation states in chemical compounds: Tl⁺ and Tl³⁺. Thermodynamically, Tl⁺ is significantly more stable and typically represents the dominant form of thallium in environmental systems. However, in this chemical form, thallium remains highly toxic. This study focuses on the modification of a glassy carbon electrode (GCE) with silver nanostructures stabilised by potato starch derivatives. The modified electrode (GCE/AgNPs-E1451) was used for the determination of trace amounts of thallium ions using anodic stripping voltammetry. Emphasis was placed on assessing the effect of surface modification on key electrochemical performance parameters of the electrode. Measurements were carried out in a base electrolyte (EDTA) and in a real soil sample collected from Bali. The stripping peak current of thallium exhibited linearity over the concentration range from 19 to 410 ppb (9.31 × 10⁻⁸ to 2.009 × 10⁻⁶ mol/dm³). The calculated limit of detection (LOD) was 18.8 ppb (9.21 × 10⁻⁸ mol/dm³), while the limit of quantification (LOQ), corresponded to 56.4 ppb (2.76 × 10⁻⁷ mol/dm³). The GCE/AgNPs-E1451 electrode demonstrates several significant advantages, including a wide detection range, reduced analysis time due to the elimination of time-consuming pre-concentration steps, and non-toxic operation compared to mercury-based electrodes. Full article

In this study, we report the synthesis, characterization, and performance evaluation of a series of bimetallic Pt_xRh_y/C electrocatalysts with systematically varied Rh content for glycerol electrooxidation in acidic and alkaline media. The catalysts were prepared via a polyol reduction method using ethylene glycol as both a solvent and reducing agent, with prior functionalization of Vulcan XC-72 carbon to enhance nanoparticles (NPs) dispersion. High-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) analyses indicated the spatial co-location of Rh atoms alongside Pt atoms. Electrochemical studies revealed strong composition-dependent behavior, with Pt₉₅Rh₅/C exhibiting the highest activity toward glycerol oxidation. To elucidate the origin of raised results, density functional tight binding (DFTB) simulations were conducted to model atomic distributions and evaluate energetic parameters. The results showed that Rh atoms preferentially segregate to the surface at higher concentrations due to their lower surface energy, while at low concentrations, they remain confined within the Pt lattice. Among the series, Pt₉₅Rh₅/C exhibited a distinctively higher excess energy and less favorable binding energy, rationalizing its lower thermodynamic stability. These findings reveal a clear trade-off between catalytic activity and structural durability, highlighting the critical role of the composition and nanoscale architecture in optimizing Pt-based electrocatalysts for alcohol oxidation reactions. Full article

(1) Background: gold nanoparticles (AuNPs) are of particular interest in biomedical research because they possess unique optical properties. In particular, its localized surface plasmon resonance is widely used for photothermal therapy and for detecting molecular interactions at nanoparticle surfaces. To enhance circulation time and biocompatibility, nanoparticles are often coated to shield their hydrophobic character. (2) Methods: we explored the seed-growth method to coat AuNPs with phospholipids to improve colloidal stability. (3) Results: various charged phospholipids were tested, and particle size and zeta potential were characterized. The monodispersity of the coated nanoparticles strongly depends on the narrow size distribution of both gold nanoparticles seeds and lipid vesicles. Achieving stable coated AuNPs with zwitterionic lipids such as phosphatidylcholine was challenging, whereas coatings containing phosphatidylglycerol did not compromise nanoparticle stability. (4) Conclusions: coating AuNPs with phospholipids via the seed-growth method has potential but requires further optimization to improve reproducibility and achieve stable nanoparticles with near-neutral surface charge. Full article

This study used Rosa roxburghii Tratt. crude extract (RR) as a reducing, stabilizing, and modifying agent for the green synthesis of gold nanoparticles (RR-AuNPs) via the one-pot method for the first time and established a novel colorimetric sensor for detecting tiopronin. Initially, RR-AuNPs with a uniform particle size and stable dispersion were prepared using the reducing property of RR. Upon the introduction of tiopronin, the drug binds to the surface of RR-AuNPs through Au-S bonds and hydrogen bonds, inducing a significant aggregation of RR-AuNPs. The absorbance of the RR-AuNP solution exhibited a linear relationship with the tiopronin concentration in the range of 0.17 μM to 16.67 μM (y = 1.9157 − 0.0972x), with a detection limit of 0.19 μM. The colorimetric sensor was successfully applied to detect tiopronin in urine samples. Compared with other detection methods, this approach is simple to operate and has a high sensitivity, a wide linear range, and a low detection limit. Full article

This study employed an integrated computational approach to discover novel nucleoprotein (NP) inhibitors for influenza A virus (IAV). Beginning with virtual screening of over 10 million compounds using Schrödinger’s Glide module (HTVS, SP, XP docking), the workflow identified promising candidates with favorable binding energies. Subsequent molecular mechanics/generalized born surface area (MM-GBSA) calculations and 100 ns molecular dynamics (MD) simulations prioritized 16 compounds for experimental validation. Surface plasmon resonance (SPR) assays revealed that compounds 8, 13, and 14 demonstrated superior target engagement, showing equilibrium dissociation constants (K_D) of 7.85 × 10⁻⁵ M, 3.82 × 10⁻⁵ M, and 6.97 × 10⁻⁵ M, respectively. Molecular dynamics, alanine scanning mutagenesis, and quantum mechanics/molecular mechanics (QM/MM) analysis were conducted to analyze the binding modes, providing a reference for the design of subsequent compounds. These findings validate the efficacy of structure-based virtual screening in identifying high-affinity NP inhibitors and provide insights for the development of broad-spectrum anti-influenza therapeutics. Full article

Penicillin G (PEN) is a widely used antibiotic for treating microbial infections. However, its extensive use in veterinary medicine can lead to accumulation in animal-derived products, particularly milk and meat. This highlights the urgent need for rapid and sensitive antibiotic detection methods. In this study, we employed DNA aptamers for the detection of PEN and for the analysis of aptamer specificity using a combined approach based on quartz crystal microbalance with dissipation monitoring (QCM-D) and localized surface plasmon resonance (LSPR). QCM-D measures changes in resonant frequency, Δf, and dissipation, ΔD, while LSPR monitors wavelength shifts in the extinction spectra corresponding to changes at the surface of gold nanoparticles (AuNPs). Thiolated aptamers were chemisorbed onto the surface of AuNPs with a diameter of 80 nm. In the presence of PEN, a redshift in the extinction spectra and a decrease in resonant frequency were observed, accompanied by an increase in dissipation due to surface viscosity effects. Significant changes in both acoustic and LSPR signals were observed at PEN concentrations as low as 1 nM. The limits of detection (LOD) for PEN, determined by QCM-D (3.0 nM, or 1.05 ng/mL)) and LSPR (3.1 nM, or 1.09 ng/mL), were similar and both were lower than the maximum residue limit (MRL) for PEN established by the EU (4 ng/mL). Full article

As the direct energy source in organisms, accurate and simple detection of adenosine triphosphate (ATP) is of great significance. Herein, a colorimetric aptasensor for ATP determination was designed by integrating the CRISPR/Cas12a system with an aptamer, and with Prussian blue nanocube and gold nanoparticle co-functionalized MoS₂ (MoS₂-PBNCs-AuNPs) nanozymes. As expected, the introduced CRISPR/Cas12a system and aptamer could efficiently amplify the detection signal and improve the specific recognition ability, respectively. Meanwhile, the catalytic activity of the MoS₂-PBNCs-AuNPs nanozymes can be regulated with the concentration of ATP. The high-affinity binding of ATP to the aptamer competitively inhibited aptamer-crRNA hybridization, causing fewer Cas12 proteins to be activated. As a result, the uncleaved single-stranded DNA (ssDNA) adsorbed onto the surface of nanozymes to effectively enhance their catalytic oxidation capability toward 3,3′,5,5′-tetramethylbenzidine (TMB). According to this phenomenon, this CRISPR-enhanced colorimetric aptasensor can detect down to 0.14 μM ATP with high selectivity, reproducibility, and stability. In addition, acceptable recoveries and low relative standard deviations of the aptasensor for ATP determination suggest that it is promising for application in early detection of clinical-related diseases. Full article

We explore a plasmonic interface for perovskite solar cells (PSCs) by integrating inkjet-printed TiO₂-AuNP microdot arrays (MDA) into the electron transport layer. This systematic study examines how the TiO₂ blocking layer (BL) surface conditioning, AuNP layer positioning, and nanoparticle loading collectively influence device performance. Pre-annealing the BL increases its hydrophobicity, yielding smaller and denser AuNP microdots with an enhanced localized surface plasmon resonance (LSPR). Positioning the AuNP MDA at the BL/perovskite interface (above the BL) maximizes near-field plasmonic coupling to the absorber, resulting in higher photocurrent and power conversion devices; these trends are corroborated by finite-difference time-domain (FDTD) simulations. Moreover, these devices demonstrate better stability over time compared to those with AuNPs at the transparent electrode (under BL). Although higher AuNP concentrations improve dispersion stability, preserve MAPI crystallinity, and yield more uniform nanoparticle sizes, device measurements showed no performance gains. After annealing, the samples with the Au content of 23 wt% relative to TiO₂ achieved optimal PSC efficiency by balancing plasmonic enhancement and charge transport without the increased resistance and recombination losses seen at higher loadings. Importantly, X-ray diffraction (XRD) confirms that introducing the TiO₂-AuNP MDA at the interface does not disrupt the perovskite’s crystal structure, underscoring the structural compatibility of this plasmonic enhancement. Overall, our findings highlight a scalable strategy to boost PSC efficiency via engineered light-matter interactions at the nanoscale without compromising the perovskite’s structural integrity. Full article

The synthesis of precious metal nanoparticles (PM-NPs) is an important field of research that has expanded significantly in recent decades due to their numerous applications. Therefore, research has been directed toward developing green methods for the synthesis of such nanoparticles that are simple, safe, eco-friendly, efficient, and sustainable. In this context, the use of marine algae biomass for the green synthesis of PM-NPs can be a viable large-scale alternative, as algae are easy to cultivate, have a rapid growth rate, and are widely distributed across many regions of the globe. The reduction of precious metal ions takes place at the surface of algae biomass particles, and the characteristics of the resulting precious metal nanoparticles depend on the experimental conditions (pH, amount of algae biomass, contact time, etc.), as well as on the type of algae biomass and the speciation form of the metal ions in the solution. All these factors significantly influence the properties of precious metal nanoparticles, and their understanding allows the development of synthesis strategies that can be applied on a large scale. The aim of this review is to provide a comprehensive overview of the way in which PM-NPs can be synthesized using algae biomass. The importance of experimental conditions (such as pH, contact time, amount of biomass, type of algal biomass, temperature, etc.) on the synthesis efficiency, as well as the elementary steps involved in the synthesis, is also discussed in this study. Particular attention has been paid to the analytical methods used for characterizing PM-NPs, as they provide crucial data regarding their structure and composition. These aspects are essential for identifying the practical applications of PM-NPs. Full article

Background/Objectives: The design of scaffolds that mimic the extracellular matrix has gained increasing attention in regenerative medicine. This study aims to develop and characterize electrospun nanofibrous scaffolds based on pullulan blended with either gelatin or gliadin and doped with selenium nanoparticles (Se NPs), to assess the influence of protein type and Se NP doping on scaffold performance and regenerative potential. Methods: Se NPs were synthesized via redox reaction and stabilized using pullulan. Electrospun scaffolds were then prepared by blending pullulan-stabilized Se NPs with either gelatin or gliadin. The resulting fibers were characterized using a multidisciplinary approach, including physicochemical (morphology, fiber dimension, swelling capacity, surface zeta potential, mechanical properties) and preclinical properties (antioxidant properties, fibroblast adhesion and proliferation, collagen expression). Results: Protein type influenced fiber morphology and dimensions, as well as mechanical behavior, with gelatin-based scaffolds demonstrating smaller fiber diameters and higher mechanical properties. The doping with Se NPs enhanced scaffold antioxidant properties without affecting fiber formation. Moreover, all scaffolds supported fibroblast proliferation, but those containing Se NPs showed enhanced modulation of ECM gene expression. Conclusions: The results show that scaffolds doped with Se NPs exhibited superior performance compared to the undoped counterparts, offering promising platforms for chronic wound reparation. Full article

Background/Objectives: Covalent conjugation of an antibiotic vancomycin (VCM) moiety and a photosensitizing mesochlorin (mChl_Pd) unit into one molecular entity may present the potential to produce the combinatorial effect of both antibacterial photodynamic therapeutic (aPDT) and antibiotic activities. Our recent study indicated that a short linkage of <4 (C−C/or C−N) bond distances between these two moieties resulted in significant steric hindrance due to the bulky VCM, which greatly reduces the accessibility of the agent to the cell surface of methicillin-resistant Staphylococcus aureus (MRSA). The observed aPDT efficacy was found to be minimal. Here, we report that the revision of this linkage, via an EG₁₀ unit using identical synthetic procedures, was able to resolve the issue. Methods: Accordingly, the corresponding combinatorial aPDT−antibiotic compound, consisting of two covalently bonded quaternary ammonium pentacationic arms on the mesochlorin chromophore core, designated as VCMe-mChl_Pd-N₁₀⁺ (LC40e⁺), was prepared for applications in antibacterial photodynamic inactivation (aPDI) activity. It was selected to investigate its enhanced binding and targeting ability to the surface of Gram-positive MRSA cells. Subsequent antibacterial photodynamic therapeutic (aPDT) activity to inactivate MRSA was investigated to substantiate the corresponding cell-surface binding effect on the efficacy of aPDT. Results: We found that the covalent combination of 10 positive charges and an MRSA-targeting vancomycin (VCM) moiety in a conjugated structure, functioning as an antibiotic–decacationic photosensitizing agent (Abx-dcPS), was capable of largely improving the MRSA cell-targeting efficiency. Importantly, variation in the chain length of the oligo(ethylene glycol) linker of VCMe-mChl_Pd-N₁₀⁺, which was sufficiently long enough to properly separate the photoactive mesochlorin ring moiety from the VCM moiety within the molecular structure, resulted in significantly enhanced aPDT activity. The new conjugate provided nearly complete eradication (>6.5-log₁₀ colony-forming units (CFU) reduction) of MRSA cells in vitro. The aPDT efficacy followed the order Abx-dcPS (combinatorial decacationic) > dcPS (decacationic) >> nPS (nonionic). This order was also verified by the relative physical binding trend of these PSs using either nPS-, dcPS-, or Abx-dcPS-pretreated and pre-fixed MRSA cells in investigations of fluorescent confocal microscopy, UV–vis fluorescence spectroscopy, and transmission electron microscopy (TEM). Conclusions: Furthermore, the molecular conjugate of Abx-dcPS may provide covalent co-delivery of two drug components concurrently, which might also serve as an effective antibiotic agent after aPDT and potentially prevent the reoccurrence of MRSA-induced infection. Full article

Non-point source pollution (NPS) from agriculture is a primary driver of water eutrophication, necessitating effective control for regional water ecological security and sustainable agricultural development. This study focuses on the Chenzhuang village watershed, a typical green agricultural demonstration area in Jiangsu Province, using the HYPE model to analyze hydrological processes and Total Nitrogen (TN) and Total Phosphorus (TP) migration patterns. The model achieved robust performance, with Nash–Sutcliffe Efficiency (NSE) values exceeding 0.7 for daily runoff and 0.35 for monthly TN and TP simulations, ensuring reliable predictions. A multi-scenario simulation framework evaluated the synergistic control effectiveness of Best Management Practices (BMPs), including agricultural production management, nutrient management, and landscape configuration, on TN and TP pollution. The results showed that crop rotation reduced annual average TN and TP concentrations by 11.8% and 13.6%, respectively, by shortening the fallow period. Substituting 50% of chemical fertilizers with organic fertilizers decreased TN by 50.5% (from 1.92 mg/L to 0.95 mg/L) and TP by 68.2% (from 0.22 mg/L to 0.07 mg/L). Converting 3% of farmland to forest enhanced pollutant interception, reducing TN by 4.14% and TP by 2.78%. The integrated BMP scenario (S13), combining these measures, achieved TN and TP concentrations of 0.63 mg/L and 0.046 mg/L, respectively, meeting Class II surface water standards since 2020. Economic analysis revealed an annual net income increase of approximately 15,000 CNY for a 50-acre plot. This was achieved through cost savings, increased crop value, and policy compensation. These findings validate a “source reduction–process interception” approach, providing a scalable management solution for NPS control in small rural watersheds while balancing environmental and economic benefits. Full article

Nanoplastics have emerged as significant global pollutants, drawing worldwide concern. Due to their small particle size, large specific surface area, and high surface activity, nanoplastics can combine with other environmental contaminants, including environmental nanoparticles, persistent organic pollutants, antibiotics, and endocrine-disrupting chemicals. This review summarizes recent progress on the environmental behavior of nanoplastics and their complex effects on food safety when co-exposed to various contaminants. These composite pollutants accumulate in foods and the environment, and are ultimately taken up by humans, posing potential toxic effects on human health. In the future, the interaction mechanisms between environmental NPs and various co-contaminants, as well as their transfer routes from food to humans, should be addressed. Full article

Among the many nanomaterials studied for biomedical uses, silica and gold nanoparticles have gained significant attention because of their unique physical and chemical properties and their compatibility with living tissues. Mesoporous silica nanoparticles (MSNs) have great stability and a large surface area, while gold nanoparticles (AuNPs) display remarkable optical features. Both types of nanoparticles have been widely researched for their individual roles in drug delivery, imaging, biosensing, and therapy. When combined with gadolinium (Gd), a common contrast agent, these nanostructures provide improved imaging due to gadolinium’s strong paramagnetic properties. This study focuses on incorporating gold nanoparticles and gadolinium into a silica matrix to develop a theranostic system. Various analytical techniques were used to characterize the nanocomposites, including infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), thermogravimetric analysis (TGA), nitrogen adsorption, scanning electron microscopy (SEM), dynamic light scattering (DLS), X-ray fluorescence (XRF), X-ray diffraction (XRD), vibrating sample magnetometry (VSM), and neutron activation analysis (NAA). Techniques like XRF mapping, XANES, nitrogen adsorption, SEM, and VSM were crucial in confirming the presence of gadolinium and gold within the silica network. VSM and EPR analyses confirmed the attenuation of the saturation magnetization for all nanocomposites. This validates their potential for biomedical applications in diagnostics. Moreover, activating gold nanoparticles in a nuclear reactor generated a promising radioisotope for cancer treatment. These results indicate the potential of using a theranostic nanoplatform that employs mesoporous silica as a carrier, gold nanoparticles for radioisotopes, and gadolinium for imaging purposes. Full article