Dispersion Of Nanoparticles Research Articles

Mesoporous silica-modified metal organic frameworks derived bimetallic electrocatalysts for oxygen reduction reaction in microbial fuel cells

The design of cost-effective oxygen reduction reaction (ORR) catalysts in microbial fuel cells (MFCs) remains a challenge. Herein, a mesoporous silica (mSiO2) assisted protection strategy is developed to synthesize highly dispersed CuCo nanoalloys embedded in nitrogen doped carbon Cu/Co-NC@mS catalyst using zeolitic imidazolate framework (ZIF) as carbon and nitrogen sources. The results revealed that the mSiO2 protection holds the potential to inhabit CuCo nanoalloys from aggregation and thus promotes the formation of highly dispersed small CuCo nanoparticles. The obtained catalyst with pyrolysis temperature (T) of 800 °C (Cu/Co-NC@mS-800) achieves the best ORR performance among Cu/Co-NC@mS-T catalysts, yielding a maximum power density of 1000 mW m−2 when employed as air cathode MFCs. The significantly enhanced ORR performance of Cu/Co-NC@mS-800 could be attributed to following aspects: a) highly dispersed small CuCo nanoalloy particles, improved mesoporous surface area and volume owing to mSiO2 protection; (b) the formation of concave regular dodecahedron mesoporous structure with thin graphtic carbon layer as support; (c) the synergetic effect between CuCo nanoalloys. This work provides a facile strategy for the preparation of highly dispersed bimetal nanoalloys with enhanced electrocatalytic performance for energy-related applications.

Superspreading Wetting of Nanofluid Droplet Laden with Highly Dispersed Nanoparticles.

Wetting of nanofluids containing highly dispersed nanoparticles of single-nanometer size was investigated, as these nanoparticles can persist within a nanometer-scale liquid film near contact line, potentially causing significant changes in wetting characteristics. We discerned distinctive superspreading wetting, featured by temporal indices (0.29 to 0.46) in the relationship between contact radius and time. We employed a phase-shifting imaging ellipsometer to measure droplet shape, including the nanometer-scale liquid film and nanoparticle layer after drying. The liquid film shapes differed from pure liquids at micrometer-scale but not at nanometer-scale. Furthermore, surface tension measurements and substrate surface energy control contributed to unraveling these characteristics. These findings differentiated the observed superspreading wetting from the mechanisms proposed in existing studies of aqueous surfactant solutions.

Highly effective catalytic degradation of bisphenol a through activation of peroxymonosulfate by an Fe-Nx structure anchored on novel lignin-based graphitic biochar: Electron transfer mechanism

A lignin-based Fe/N co-doped carbonaceous catalyst was synthesized via freeze-drying followed by pyrolysis to activate peroxymonosulfate (PMS) for efficient degradation of bisphenol A (BPA). The Fe/N co-doped biochar exhibited a high specific surface area (364.84 m2/g), hierarchical porous structures, and abundant oxygen-containing functional groups (hydroxyl and carboxyl groups), which enhancing the dispersion of Fe3O4 nanoparticle and exposure of catalytic site. The Fe8-N10-C/PMS system achieved 100 % BPA degradation within 20 min with a corresponding first-order reaction rate constant (kobs) of 0.4056 min−1, which outperformed most reported catalysts in efficiency. Quenching and EPR analyses revealed that both free radicals (•OH, SO4•−, and O2•−) and non-radical (1O2) were rate-limiting steps, while graphitic N and Fe-Nx structures facilitated direct electron transfer from BPA to PMS in electrochemical tests. XPS results confirmed that pyrrolic N, rather than pyridinic N, played a crucial role in forming the Fe-Nx structure. Moreover, the catalyst showed excellent stability, regeneration capability, and adaptability under diverse conditions, highlighting the potential of the Fe-N-C/PMS system for practical wastewater treatment applications.

Efficient lignin hydrogenolysis over N-doped macroporous carbon supported Ru catalyst

To cope with the challenge of insufficient interaction between lignin macromolecules and catalytic active sites in heterocatalysis systems which hindered the efficient hydrogenolysis of lignin, a lignin-derived N-doped macroporous carbon supported Ru catalyst (Ru/LNPC) was prepared via the pyrolysis of alkali lignin with potassium hydroxide as the activator and ammonium oxalate as the pore forming agent. The LNPC carrier featured a hierarchical porous structure with the diameter of macropores ranging from 50 nm to 10 μm, enhancing the adequately contact between the lignin macromolecules and Ru NPs. The doping nitrogen in the carbon carrier led to well dispersed Ru nanoparticles with average size of 1.08 nm, providing abundant active metallic centers. Therefore, Ru/LNPC exhibited excellent catalytic activity and stability to hydrogenolysis of lignin. Under the condition of 1.0 MPa H2 at 280 ºC for 2 h, Ru/LNPC contributed to the yield of 45.6 % aromatic monomers from the depolymerization of lignin. After five recycling, Ru/LNPC still showed significant activity. This work provided a new strategy for designing catalysts for efficient hydrogenolysis of lignin and further facilitating its high-value utilization.

Highly dispersive nickel vanadium oxide nanoparticles anchored on nickel cobalt phosphate micron-sheets as cathodes for high-energy hybrid supercapacitor devices

The effective strategies of customizing suitable orientation and rationalizing structures are significant for developing high-performance energy storage materials applied in supercapacitors, which are regarded as promising clean energy storage devices. To obtain highly efficient MOF (metal-organic framework)-derived phosphate electrode, it is necessary to combine it with highly conductive materials for a synergistical effect. So, in this work, the Ni-Co DH (double hydroxide) is used as sacrificial template to prepare MOF through a reverse strategy, which makes a foundation for shaping anisotropic orientation to impede structural stack. The Ni3V2O8 nanoparticles are dispersedly anchored on NiCo-P micron-sheet through a conversion from nanostructured MOF/Ni3V2O8. The evolution in structural size avoids agglomeration of Ni3V2O8 nanoparticles, which also leads to shaggy and intact NiCo-P micron-sheets, thereby improving fully contact with electrolyte. As a result, the obtained NiCo-P/Ni3V2O8 with abundant electroactive sites and valences displays extraordinary specific capacitance of 2520 F g−1 (1134 mA h g−1) at 1 A g−1 with capacitance retention of 89.05 % even when the current density increases to 10 A g−1. The NiCo-P/Ni3V2O8 and AC as cathode and anode, respectively, are assembled into a hybrid supercapacitor (HSC) device to fulfil requirement for high-performance supercapacitor devices. As-made NiCo-P/Ni3V2O8//AC HSC delivers preeminent specific energy density (SE) of 65 Wh Kg−1 at specific power density (SP) of 750 W Kg−1.

Catalytic depolymerization of poly(ethylene terephthalate) plastic into value-added monomers using metal-modified mesoporous silica

The glycolysis of poly(ethylene terephthalate) (PET), a polymer extensively used in food packaging, into bis(2-hydroxyethyl) terephthalate (BHET) monomers was investigated using mesoporous silica supported by metal oxide as catalysts. Among these, a catalyst composed of ZnO supported on KIT-6 (5%ZnO/KIT-6) showed an effective performance in PET glycolysis, achieving a BHET yield of 92.1% with complete conversion of PET. Additionally, the catalyst demonstrated exceptional reusability and high efficiency in handling post-consumer PET plastics, with BHET yields reaching up to 89%. Characterization studies revealed that the highly dispersed ZnO nanoparticles trapped in KIT-6 channels formed strong interactions with surface Si-OH groups, leading to an enhanced acid strength and an increased number of acid sites, which significantly improved PET depolymerization. This study presents an innovative solution for the recycling of PET plastic, contributing to industrial development and reducing the impact of plastic waste.

Surface Cladding of Mild Steel Coated with Ni Containing TiO2 Nanoparticles Using a High-Temperature Arc from TIG Welding

This study explores the use of a high-temperature arc generated during tungsten inert gas (TIG) welding to enhance the mechanical properties of the surface of AISI 1020 steel. An innovative two-step process involves using the high-temperature arc as an energy source to fuse a previously electrodeposited Ni/TiO2 coating to the surface of the substrate. The cladded surface is characterised by a scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS), an optical microscope (O.M.) equipped with laser-induced breakdown spectroscopy (LIBS), Vicker’s microhardness testing, and pin-on-plate wear testing. The treated surface exhibits a unique amalgamation of hardening mechanisms, including nanoparticle dispersion strengthening, grain size reduction, and solid solution strengthening. The thickness of the electrodeposited layer appears to strongly influence the hardness variation across the width of the treated layer. The hardness of the treated layer when the Ni coating contains 30 nm TiO2 particles was found to be 451 VHN, validating an impressive 2.7-fold increase in material hardness compared to the untreated substrate (165 VHN). Similarly, the treated surface exhibits a twofold improvement in wear resistance (9.0 × 102 µm3/s), making it substantially more durable in abrasive environments than the untreated surface. Microstructural and EDS analysis reveal a significant reduction in grain size and the presence of high concentrations of Ni and TiO2 within the treated region, providing clear evidence for the activation of several strengthening mechanisms.

New Carrageenan/2-Dimethyl Aminoethyl Methacrylate/Gelatin/ZnO Nanocomposite as a Localized Drug Delivery System with Synergistic Biomedical Applications

In recent years, the development of multifunctional hydrogels has gained significant attention due to their potential in various biomedical applications, including antimicrobial, antioxidant, and anticancer therapies. By integrating biocompatible polymers and nanoparticles, these hydrogels can achieve enhanced activity and targeted therapeutic effects. In this study, carrageenan/2-dimethyl aminoethyl methacrylate/gelatin (CAR/DEMA/Gelt) composite hydrogel was synthesized using microwave radiation specifically for its efficiency in enhancing cross-linking and promoting uniform nanoparticle dispersion within the matrix. Zinc oxide (ZnO) nanoparticles were incorporated into the hydrogel to form the (CAR/DEMA/Gelt/ZnO) nanocomposite. The hydrogels were characterized using FT-IR, FE-SEM, XRD, TGA, and EDX, confirming successful cross-linking and structural integrity. The nanocomposite hydrogel exhibited more enhanced antimicrobial activity than the composite hydrogel against Gram-positive Staphylococcus aureus (S. aureus) and Bacillus subtilis (B. subtilis), with inhibition zones of 15 mm and 16 mm, respectively, while in case of the Gram-negative bacteria, Klebsiella pneumoniae (K. pneumoniae) and Escherichia coli (E. coli), the inhibition zones were 29 mm and 19 mm, respectively. In addition to the unicellular fungi, Candida albicans (C. albicans), the inhibition zone was 19 mm. Moreover, the nanocomposite showed anti-inflammatory activity comparable to those of Indomethacin and antioxidant activity, with an impressive IC50 value of 33.3 ± 0.05 µg/mL. In vitro cytotoxicity assays revealed significant anticancer activity. Against the MCF-7 breast cancer cell line, the CAR/DEMA/Gelt/ZnO nanocomposite showed 72.5 ± 0.02% cell viability, which decreased to 30.8 ± 0.01% after loading doxorubicin (DOX). Similarly, against the HepG2 liver cancer cell line, the free nanocomposite displayed 59.9 ± 0.006% cell viability, which depleted to 29.9 ± 0.005% when DOX was uploaded. This CAR/DEMA/Gelt/ZnO nanocomposite hydrogel demonstrates strong potential as a multifunctional platform for targeted biomedical applications, particularly in cancer therapy.

Design of solid lipid nanoparticles for skin photoprotection through the topical delivery of caffeic acid-phthalimide

Exposure of the skin to ultraviolet (UV) radiation is associated with many pathological conditions such as premature aging and skin cancer. Furthermore, members of Nicotinamide Adenine Dinucleotide Phosphate-oxidase (NADPH oxidase or NOX) enzyme family can produce UV-induced reactive oxygen species (ROS), even after cessation of radiation exposure. The caffeic acid-phthalimide (CF) compound is a potent antioxidant, which reduces the generation of ROS. However, its high lipophilicity may hamper its permeation through the skin. Solid lipid nanoparticles (SLNs) can ensure close contact and increase the amount of drug absorbed into the skin. The present work aims to develop and optimize SLNs containing CF to achieve enhanced skin photoprotection along with antioxidant and anti-aging effects. SLNs were prepared by the hot homogenization method using Compritol 888 ATO as the lipid matrix, and Tween 80 and Pluronic® F-127 as the surfactants to stabilize nanoparticle dispersion. The particles had high stability for at least 30 days. Physicochemical characterizations of the selected SLNs formulations showed sizes in the range 150–180 nm, polydispersity index (PDI) of 0.2, and a negative zeta potential (≅ −25 mV). The SLNs had high CF entrapment efficiency (96–97 %) and showed a controlled drug‐release profile. The in vitro study revealed low cytotoxic properties of CF-loaded SLNs towards fibroblasts and a photoprotective effect, reflected from the increased viability of UVB-irradiated fibroblasts treated with CF-SLNs. Moreover, the CF-SLNs induced fibroblast migration and closure, showing that these nanosystems offer not only biological photoprotection, but also stimulate wound healing.

Water–Gas Shift over Pt Nanoparticles Dispersed on CeO2 and Gadolinium-Doped Ceria (GDC) Supports with Specific Nano-Configurations

The water–gas shift (WGS) reaction is one of the most significant reactions in hydrogen technology since it can be used directly to produce hydrogen from the reaction of CO and water; it is also a side reaction taking place in the hydrocarbon reforming processes, determining their selectivity towards H2 production. The development of highly active WGS catalysts, especially at temperatures below ~450 °C, where the reaction is thermodynamically favored but kinetically limited, remains a challenge. From a fundamental point of view, the reaction mechanism is still unclear. Since specific nanoshapes of CeO2-based supports have recently been shown to play an important role in the performance of metal nanoparticles dispersed on their surface, in this study, a comparative study of the WGS is conducted on Pt nanoparticles dispersed (with low loading, 0.5 wt.% Pt) on CeO2 and gadolinium-doped ceria (GDC) supports of different nano-morphologies, i.e., nanorods (NRs) and irregularly faceted particle (IRFP) CeO2 and GDC, produced by employing hydrothermal and (co-)precipitation synthesis methods, respectively. The results showed that the support’s shape strongly affected its physicochemical properties and in turn the WGS performance of the dispersed Pt nanoparticles. Nanorod-shaped CeO2,NRs and GDCNRs supports presented a higher specific surface area, lower primary crystallite size and enhanced reducibility at lower temperatures compared to the corresponding irregular faceted CeO2,IRFP and GDCIRFP supports, leading to up to 5-fold higher WGS activity of the Pt particles supported on them. The Pt/GDCNRs catalyst outperformed all other catalysts and exhibited excellent time-on-stream (TOS) stability. A variety of techniques, namely N2 physical adsorption–desorption (the BET method), scanning and transmission electron microscopies (SEM and TEM), powder X-ray diffraction (PXRD) and hydrogen temperature programmed reduction (H2-TPR), were used to identify the texture, structure, morphology and other physical properties of the materials, which together with the in situ diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) and detailed kinetic studies helped to decipher their catalytic behavior. The enhanced metal–support interactions of Pt nanoparticles with the nanorod-shaped CeO2,NRs and GDCNRs supports due to the creation of more active sites at the metal–support interface, leading to significantly improved reducibility of these catalysts, were concluded to be the critical factor for their superior WGS activity. Both the redox and associative reaction mechanisms proposed for WGS in the literature were found to contribute to the reaction pathway.

Synthesis, Dynamic Mechanical Properties of Poly(Styrene-co-Acrylonitrile) Grafting Silica Nanocomposites

A series of styrene–acrylonitrile (SAN) copolymer nanoparticles were prepared by grafting styrene–acrylonitrile from both aggregated silica and colloidally dispersed silica nanoparticles using atom-transfer radical polymerisation (ATRP). Cross-linking and macroscopic gelation were minimised by using a miniemulsion system. The thermal and mechanical behavior of composites were made from PSAN aggregated silica nanoparticles or colloidally dispersed silica has been examined by Differential scanning calorimetry (DSC) and Dynamic mechanical thermal analysis (DMTA). The filler particles increased the rubbery modulus above the Tg of PSAN considerably and led to a temperature-independent plateau of the modulus between 130 and 240 °C similar to that normally observed for crosslinked amorphous polymers. Covalent attachment of PSAN to the silica nanoparticles, by grafting the polymer from the surface of the silica using atom-transfer radical polymerization (ATRP), gave rise to hybrid materials with a comparable elastic plateau. While neat PSAN started to flow and deform irreversibly above 120 °C, the new silica nanoparticle–polymer hybrid materials proved stable up to 240 °C, which was more than 120 °C above the Tg of the polymer. Aggregated silica nanoparticles displayed more affect compared to colloidally dispersed silica.

Optimizing anode performance of (La,Sr)1-αTi1-βNiβO3-δ in solid oxide fuel cells via synergistic a-site deficiency and b-site doping regulation strategy

This study introduces an innovative approach to enhance the electrochemical performance of La-substituted SrTiO3 anode materials in solid oxide fuel cells (SOFCs) through the strategic combination of A-site deficiency and B-site doping. The effective method leverages the synergistic effects of A-site deficiency and B-site doping on Ni in situ exsolution and the electrochemical behavior of the SOFCs. The tailored (La,Sr)1-αTi1-βNiβO3-δ (α=0.2, β=0.15, (LS)0.8TN0.15) anode, modified with Ni nanoparticles, significantly boosts the power output of YSZ-supported single cells, achieving peak power densities of 720.5, 535.8, and 376.3 mW cm-2 at 800, 700, and 600 °C, respectively, under a humidified hydrogen atmosphere (3 % H2O-97 % H2). The findings underscore the pivotal role of optimized A-site deficiency and B-site doping in fine-tuning the morphology and dispersion of Ni nanoparticles, thereby markedly enhancing the catalytic activity and the overall electrochemical efficiency of the electrodes. These results indicate the promising candidacy of (La,Sr)1-αTi1-βNiβO3-δ as an anode material for SOFCs, opening new avenues for the design of high-performance fuel cell components.

Development of triple-helical recombinant collagen-silver hybrid nanofibers for anti-methicillin-resistant Staphylococcus aureus (MRSA) applications

The escalating threat of healthcare-associated infections highlights the urgent need for biocompatible antibacterial materials that effectively combat drug-resistant pathogens. In this study, we present a novel fabrication method for triple-helical recombinant collagen (THRC)-silver hybrid nanofibers, specifically designed for anti-methicillin-resistantstaphylococcus aureus(MRSA) applications. Utilizing a silver-mediated crosslinking strategy, we harness a low-power 38 W lamp to enable silver ions (Ag+) to mediate crosslinking across various proteins. Mechanistic insights reveal the pivotal role of nine amino acids in facilitating this reaction. The THRC maintains its native structure, forming well-ordered nanofibers, while other globular proteins form a distinctive network-like structure. THRC also serves as a reducing and dispersing agent, facilitating thein situsynthesis of highly dispersed silver nanoparticles (AgNPs) (∼7 nm in diameter) within the nanofibers. Systematic investigation of the reaction conditions between THRC and Ag+demonstrates the versatility of this novel approach for nanofiber fabrication. The incorporation of AgNPs imparts exceptional antibacterial activity to the THRC/AgNPs nanofibers, exhibiting a minimum inhibitory concentration of 19.2 mg l-1and a minimum bactericidal concentration of 153.6 mg l-1against MRSA. This innovative approach holds significant potential for developing antibacterial protein-based biomaterials for infection management in wound healing and other biomedical applications.

Transition metal ions-chelated COFs derived bifunctional oxygen catalysts for rechargeable Zn-air batteries

Improving energy conversion efficiency and battery cycle stability is an essential goal in energy conversion and storage, while a critical factor in achieving this goal is the design of effective bifunctional catalysts. The covalent organic framework is a new type of high molecular material that can be employed as an ideal template for quantitative chelate metal ions to synthesize highly efficient bifunctional catalysts with high dispersion metal active sites. In this work, the Fe2Ni1/NiFe2O4@NCG bifunctional catalysts are constructed by employing metal-chelated COFs and MA/GO mixture as primary precursors combined with a high-temperature pyrolysis strategy. COFs and MA serve as chelators and spacers to improve the dispersion of metal nanoparticles. The Fe2Ni1/NiFe2O4@NCG composite exhibits a large BET surface area and hierarchical structure with plentiful nanoparticles on the carbon layers. HRTEM proves the coexistence of FeNi and NiFe2O4. The optimal Fe2Ni1/NiFe2O4@NCG-800 composite shows satisfactory catalytic O2 performance, providing a half-wave potential of 0.857 V for ORR and an overpotential of 244 mV for OER. Meanwhile, DFT calculations prove that electron redistribution occurs at the interface between FeNi and NiFe2O4 after combination. The Fe2Ni1/NiFe2O4@NCG-based liquid and solid-state ZABs perform very well, exhibiting large specific capacities (796 mAh·g−1 for aqueous ZAB; 742 mAh·g−1 for solid-state ZAB) and stable charge-discharge cycle performance (300 h for aqueous ZAB; 180 h for solid-state ZAB).

Significantly improved energy storage performance of polyetherimide-based dielectric composites via employing core-shell organic-semiconductor@BaTiO3 nanoparticles

With fast development of modern industries and electrical systems, polymer dielectrics are urgently demanded to have high discharged energy density (Ud) in elevated temperature. In this paper, novel core-shell poly [2-((3,6,7,10,11-pentakis (hexyloxy) triphenylene-2-yl) oxy) ethyl methacrylate] (PHT) coated barium titanate nanoparticles (BT) (denoted as PHT@BT) are prepared, and then incorporate into polyetherimide (PEI) matrix via solution blending method. Semi-conductive organic shell layer can not only promote the dispersion and compatibility of BT nanoparticles but also construct deep trap. As a result, 0.3 wt% PHT@BT/PEI composites achieve maximal Ud of 7.62 J cm−3 at 641 MV m−1 and room temperature, which is 1.93 times that of pure PEI film (3.93 J cm−3 at 461 MV m−1). Importantly, the Ud of 4.86 J cm−3 is obtained at 150 °C. This work provides superior interfacial modifier for inorganic nanofiller, which is of great significance for the fabrication of polymer-based nanocomposites with superior Ud.

Humidity-independent gas sensor based on Pt/SnO2/NiO with advanced CO sensing capabilities

Aimed at realizing the sensors capable of functioning effectively in high-humidity environments, the Pt/SnO2/NiO ternary composite materials featuring noble metal and p-n heterojunction structures was synthesized. The dispersion of SnO2 and Pt nanoparticles on NiO nanosheets was found to be excellent, resulting in a nearly twofold increase (99.45 m2g−1 of Pt/SnO2/NiO) in specific surface area compared to pure NiO materials (51.977 m2g−1). The CO sensitivity tests revealed that, in contrast to pure NiO sensors (with an optimal operating temperature of 290°C), Pt/SnO2/NiO ternary composites exhibited an optimal operating temperature (OOT) of 270℃, a decrease of 20℃ for CO detection at a relative humidity of 22 %. At this OOT, Pt/SnO2/NiO sensors consistently displayed high responsiveness (2.5 times higher than that of the pure NiO sensor), good selectivity, and rapid response-recovery times (the recovery time is reduced by nearly half compared to that of the pure NiO sensor). Furthermore, the sensors' responses to CO under different humidity conditions (from 22 % to 91 %) at 270℃ were investigated. The results demonstrated that Pt/SnO2/NiO sensors exhibited minimal variation in their response to CO at a range of relative humidity levels (41.5 % at 91 %, 39.5 % at 22 %, respectively). These results highlight that the enhancement of CO gas sensitivity in the sensors primarily results from the high catalytic activity of noble metal Pt and the p-n heterojunction interaction.

Collagen and chitosan-based biogenic sprayable gel of silver nanoparticle for advanced wound care.

Silver nanoparticles have gained significant attention recently due to their unique antibacterial properties, making them promising candidates for wound care applications. This study proposes a novel approach for advanced wound care using a silver nanoparticle-impregnated biogenic spray hydrogel supplemented with collagen and chitosan. Silver nanoparticles were incorporated into the hydrogel (optimized by a QbD approach) to impart antimicrobial activity, crucial for combating wound infections and promoting faster healing. The study assessed the physical and chemical properties of the biogenic hydrogel, including its viscosity, pH, and nanoparticle dispersion characteristics. In vitro, antimicrobial efficacy against common wound pathogens and in vivo studies using chronic wound models in small animals portrayed the immense potential of the developed biogenic hydrogel in effectively reducing the bacterial load of broad-spectrum pathogens. The hydrogel exhibited excellent biocompatibility, supporting cell proliferation and tissue repair without toxic effects. It accelerated wound healing, improved collagen deposition, and enhanced tissue regeneration in the tested animals by reducing proinflammatory cytokines, ROS, and NF-kb levels. Overall, this innovative silver nanoparticle-impregnated biogenic spray hydrogel of collagen and chitosan presents a uniform spray pattern that proved efficient, showing a promising solution for advanced wound care. Its biocompatibility, safety, anti-inflammatory, antimicrobial efficacy, and wound healing properties hold great potential for improving the management of complex wounds, opening new avenues in wound care and regenerative medicine.

Multi-level pumping water system from bioengineering wood microstructure by self-growing mycelium for boosting photothermal evaporation efficiency

Due to low cost, renewability, high porosity and eco-friendliness, wood has been widely used to design solar steam generation devices, displaying great promise for clean water production in desalination and wastewater treatment. However, cleaner preparation processes and efficient structure design of wood based interfacial evaporators still need further exploration and development. Here, we reported an eco-friendly bio-incising method of wood microstructure modulation to fabricate high-performance wood-based solar steam generator by creating multi-level pumping water system. Self-growing Trametes versicolor (TV) which is a kind of bothersome wood fungus was skillfully used to increase porosity of wood and form interweaved mycelia fibers on wood surface, achieving the resegmentation and transmission of water bodies. These water-absorbing cell fibers and porous wood substrate collectively form a multi-level pumping water system ensuring effective heat management and high water evaporation area. Coupling with densely dispersed polydopamine nanoparticles (PDA NPs) on the surface of TV fiber for light absorption enhancement, the designed wood based solar steam generator with a smallest thickness of 1 mm shows outstanding evaporation rate (1.61 kg·m−2·h−1) and solar energy conversion efficiency (98.4 %) under simulated 1 sun irradiation. Moreover, the obtained clean water using as-prepared steam generator shows high removal rates both in simulated seawater and wastewater. This work presents a novel concept and green method for designing high-performance wood-based solar steam generator with multi-level pumping water system.

Colloidal gold dispersions in orogenic gold from the Barberton Greenstone Belt, South Africa

The mechanisms of gold grain growth, as a necessary precursor to gold hyper-accumulation and the formation of high-grade ore deposits, remain equivocal. This is particularly true for orogenic gold deposits where primary growth textures may be poorly preserved due to episodic fault re-activations during successive seismic events. A sample collected from the Fairview Mine in the Barberton Greenstone Belt (South Africa) and subjected to non-destructive SELFRAG sample preparation and subsequent scanning electron microscopy provides rare capture of images of millimeter-scale gold grains associated with dispersed spheroidal gold colloids and nanoparticles (<5 nm to >1 µm diameter). Although the ultimate provenance of these gold spheroids remains equivocal, textural evidence suggests a net addition of mass to the adjacent gold grains. We suggest that Ostwald ripening (a process of particle growth or coarsening by diffusion) and coalescence may contribute to gold grain growth in this sample.

1D, 2D, and 3D Micropatterning of ZnO Nanoparticles and Nanorod by Two‐Photon Polymerization and Surface Functionalization

AbstractIn this paper, a novel method is proposed for selective deposition of ZnO nanoparticles (NPs) and growth of ZnO Nanorods (NRs) on multi‐dimensional patterned polymer surfaces. The method involves microfabrication of functionalized 1D, 2D, and 3D polymer structures by two‐photon polymerization (TPP) followed by selective assembly of ZnO NPs acting as seeds before growing ZnO NRs by chemical bath deposition (CBD) technique at low temperature. The immobilization of the ZnO NPs seed layer is done by electrostatic interaction between the positively charged polymer surface functionalized by amine groups and the negatively charged ZnO NPs functionalized by citrate molecules. The influence of citrate molecules on the stability of the ZnO NPs dispersions and their immobilization on the polymer surface is demonstrated. Spatially controlled and selective growth of ZnO NRs is shown at low temperatures on multi‐dimensional structures up to 9 mm2 and having different shapes, including 1D polymer lines, 2D microplates, and 3D arrays of cones. The diameter of NRs and their orientation can be controlled through the size of ZnO NPs and the shape of the polymer structure respectively.