A Sustainable Approach to Fabricating Ag Nanoparticles/PVA Hybrid Nanofiber and Its Catalytic Activity

Characterization and potentiality of plant-derived silver nanoparticles for enhancement of biomass and hydrogen production in Chlorella sp. under nitrogen deprived condition

Energy is a crucial entity for the development and it has various alternative forms of energy sources. Recently, the synthesis of nanoparticles using benign biocatalyst has attracted increased attention. In this study, silver nanoparticles were synthesized and characterized using Azadirachta indica plant-derived phytochemical as the reducing agent. Biomass of the microalga Chlorella sp. cultivated in BG11 medium increased after exposure to low concentrations of up to 0.48 mg L-1 AgNPs. In addition, algal cells treated with 0.24 mg L-1 AgNPs and cultivated in BG110 medium which contained no nitrogen source showed the highest hydrogen yield of 10.8 mmol L-1, whereas the untreated cells under the same conditions showed very low hydrogen yield of 0.003 mmol L-1. The enhanced hydrogen production observed in the treated cells was consistent with an increase in hydrogenase activity. Treatment of BG110 grown cells with low concentration of green synthesized AgNPs at 0.24 mg L-1 enhanced hydrogenase activity with a 5-fold increase of enzyme activity compared to untreated BG110 grown cells. In addition, to improve photolytic water splitting efficiency for hydrogen production, cells treated with AgNPs at 0.24 mg L-1 showed highest oxygen evolution signifying improvement in photosynthesis. The silver nanoparticles synthesized using phytochemicals derived from plant enhanced both microalgal biomass and hydrogen production with an added advantage of CO2 reduction which could be achieved due to an increase in biomass. Hence, treating microalgae with nanoparticles provided a promising strategy to reduce the atmospheric carbon dioxide as well as increasing production of hydrogen as clean energy.

Facile Fabrication of SERS Substrates by the Electrodeposition Method to Detect Pesticides with High Enhancement Effect and Long-Term Stability

In this study, surface-enhanced Raman scattering substrates were investigated by the electrodeposition method to detect low concentrations of pesticides via the electrodeposition method with different agents from silver and gold precursors on APTES-modified ITO glass. A dual-potential method supplied three electrodes and was performed with a nucleation potential of 0.7 V for 2 s and a growth potential of -0.2 V for 500 s. The Ag film produced by the electrodeposition approach has great surface uniformity and good SERS signal amplification for the thiram insecticide at low concentrations. Interestingly, the ITO/APTES/Ag substrate extensively increased the sensitivity than the other investigated ones, thanks to the adequate assistance of amino groups of APTES in the denser and hierarchical deposition of Ag NPs. These observations were additionally elucidated via finite-difference time-domain (FDTD) calculation. For thiram, the detection was set at 10-8 M with an enhancement factor of up to 3.6 × 107 times. Comparing the SERS spectra of thiram at concentrations of 10-3, 10-4, and 10-5 M with a relative standard deviation (RSD) of less than 7.0% demonstrates excellent reproducibility of the ITO/APTES/Ag substrate. In addition, the special selectivity of the ITO/APTES/Ag substrate for thiram demonstrates that these nanostructures can identify pesticides with extreme sensitivity.

Fabrication and Characterization of Silver Nanoparticle-Doped Chitosan/Carboxymethyl Cellulose Nanocomposites for Optoelectronic and Biological Applications

The synthesis of nanoparticles using environmentally friendly methods for applications in fields such as food packaging and biomedicine has been gaining increasing attention. Organic-inorganic nanostructures offer opportunities to create innovative materials suitable for use in optoelectronics and biological applications. In this study, we focused on producing nanocomposite films by blending carboxymethyl cellulose (CMC) and chitosan (CS) polymers in equal proportions (50/50 wt %) and adding silver nanoparticles (Ag NPs) through a solution casting process. Our objective was to examine how the introduction of Ag NPs influenced the structural, optical, mechanical, electrical, and antibacterial properties of the virgin CMC/CS composites. XRD patterns of the prepared samples indicated the presence of crystalline Ag phases within the CMC/CS blend. FT-IR spectroscopy showed the primary vibrational peaks associated with CMC and CS, which exhibited reduced intensity after the addition of Ag NPs. The UV absorption of the nanocomposites exhibited a gradual increase and a shift toward longer wavelengths. The electrical properties are enhanced with higher concentrations of Ag NPs. An increase in the content of Ag NPs resulted in a corresponding enhancement of antibacterial activity against both Staphylococcus aureus and Escherichia coli. The CMC/CS-Ag-doped films demonstrated significant enhancements in Young's modulus (Y), tensile stress (σt), and elongation at break (εB). These findings suggest that these nanocomposite films hold promise for potential applications in optoelectronics and biological fields.

Fabrication of silver nanoparticles decorated on sodium alginate microbeads enriched with keratin and investigation of its catalytic and antioxidant activity

In this study, an environmentally friendly, effective, easily synthesizable and recoverable nano-sized catalyst system (Ag@NaAlg-keratin) was designed by decorating Ag nanoparticles on microbeads containing sodium alginate (NaAlg) and keratin obtained from goose feathers. The structure, morphology and crystallinity of the Ag@NaAlg-keratin nanocatalyst were evaluated by XRD, FT-IR, FE-SEM, EDS/EDS mapping and TEM analyses. Catalytic ability of designed Ag@NaAlg-keratin nanocatalyst was then investigated against 4-nitrophenol (4-NP) and methyl orange (MO) reductions. Ag@NaAlg-keratin nanocatalyst effectively reduced 4-NP in 6 min and MO in 5 min, with rate constants of 0.17 min-1 and 0.16 min-1, respectively. Additionally, activation energies (Ea) were found as 39.8 kJ/mol for 4-NP and 37.9 kJ/mol for MO. Performed recyclability tests showed that the Ag@NaAlg-keratin nanocatalyst was easily recovered due to its microbead form and successfully reused five times, maintaining both its activity and structure. Furthermore, antioxidant activity of Ag@NaAlg-keratin nanocatalyst was the highest (73.16 %).

Antipathogenic Efficacy of Biogenic Silver Nanoparticles and Antibiofilm Activities Against Multi-drug-Resistant ESKAPE Pathogens

The silver nanoparticles (AgNPs) were produced by employing a biogenic loom and tested for antipathogenic assets against multi-drug-resistant (MDR) ESKAPE bacteria. Biogenically synthesized AgNPs were characterized adopting various high-throughput techniques such as UHRTEM, SEM with EDX, DLS, TGA-DTA, and XRD and spectroscopic analysis showed polydispersion of nanoparticles. In this context, AgNPs with the attribute of spherical-shaped nanoparticles with an average size of 26 nm were successfully synthesized utilizing bacterial supernatant. The antipathogenic activities of AgNPs were assessed against 11 strains of MDR ESKAPE bacteria including Enterococcus faecium; methicillin-resistant Staphylococcus aureus; Klebsiella pneumonia; Acinetobacter baumannii; Pseudomonas aeruginosa; Enterobacter aerogenes; and Enterobacter species. The exposure of biogenic AgNPs in a well diffusion assay showed all the growth inhibitions of ESKAPE bacteria at 200 μg/ml after 18 h of incubation. Growth kinetics demonstrated maximum killing at 60 μg/ml after 4 h of completion. The highest biofilm depletions were found at 100 μg/ml in adhesion assay. Live/dead assays showed effective killing of the ESKAPE bacteria at 10 μg/ml in pre-existing biofilms. The effective inhibitory concentrations of AgNPs were investigated ranging from 10 to 200 μg/ml. The selected pathogens found sensitive to AgNPs are statistically significant (P < 0.05) than that of cefotaxime/AgNO3. Consequently, a broad spectrum of antimicrobial potentials of AgNPs can be alternative to conventional antimicrobial agents for future medicine.

Anticancer effect and laser photostability of ternary graphene oxide/chitosan/silver nanocomposites on various cancer cell lines

Aims: The development of nanocomposites (NCs) of antitumor activity provides a new paradigm for fighting cancer. Here, a novel NC of green synthetic silver nanoparticles (AgNPs), graphene oxide (GO) and chitosan (Cs) NPs was developed. Materials & methods: The prepared GO/Cs/Ag NCs were analyzed using various techniques. Cytotoxicity of the NCs was evaluated against different cancer cell lines by Sulforhodamine B (SRB) assay. Results: GO/Cs/Ag NCs are novel and highly stable. UV-Vis showed two peaks at 227 and 469 nm, indicating the decoration of AgNPs on the surface of GO/Cs NPs. All tested cell lines were affected by GO/Cs NPs and GO/Cs/Ag NCs. Conclusion: The results indicate that GO/Cs/Ag NCs were present on tested cell lines and are a promising candidate for cancer therapy.

Design and Fabrication of Broad-Spectrum Antimicrobial Porous Metallo-Polymeric Microsphere for Water Disinfection

An expedient and efficient approach is used to synthesize a new class of metallo-polymeric microspheres (MPMs) as antimicrobials to succumb the wide range of bacteria from water. Three types of MPMs, that is, poly[Silver (I)-methacrylate-co-methylmethacrylate] (pAgMA), poly[Copper (II)-methacrylate-co-methyl methacrylate] (pCuMA), and poly[Nickel (II)-methacrylate-co-methylmethacrylate] (pNiMA), are prepared via radical suspension polymerization technique in 3D shape with porous texture. The structural and morphological characterization of the prepared microspheres are examined by analytical techniques. The antimicrobial potentialities of prepared MPMs are investigated at the laboratory scale study, revealing that the MPMs exhibit strong antibacterial activity (≈99.9% killing) against Gram-negative and Gram-positive bacteria [Enterobacter hormaechei (EH), Bacillus megatarium (BM), and Bacillus bataviensis (BB)]. The MacConkey agar medium test reveals that MPMs have substantial biocidal efficacy against broad-spectrum Gram-negative bacteria present in tap water. The MPMs exhibit significant antimicrobial efficacy via contact killing owe to the presence of integrated biocidal metal moiety, which represents that the MPMs are safe for water disinfection.

Refining shape and size of silver nanoparticles using ion irradiation for enhanced and homogeneous SERS activity

We present green synthesis of silver nanoparticles in water using unirradiated and Ag15 + ion irradiated phytoextracts of Bergenia Ciliata leaf, Eupatorium adenophorum leaf, Rhododendron arboreum leaf and flower. The use of different plant extracts and their subsequent ion irradiation allow for successful refinement of nanoparticle size and morphology. Due to changes in reducing and capping agents the nanoparticle surface functionalization also varies which not only controls the morphology but also allows for surface oxidation and aggregation processes. In this work, we have synthesized silver nanoparticles which exhibit sizes in the range from 13 to 24 nm and having shapes like spherical, quasispherical, trigonal, hexagonal, cylindrical, dendritic assemblies, and porous nanoparticles. Owing to changes in the size and shape of the nanoparticles, their direct bandgap (2.05 eV - 2.48 eV) and local surface plasmon resonance (420 nm - 490 nm) could also be tuned. These nanoparticles are examined as SERS substrates, where their enhancement factors, limit of detection for methylene blue, and SERS substrate homogeneity have been tested. It has been observed the nanoparticles synthesized using unirradiated plant extracts present an enhancement factor of 106 with a limit of detection 10- 8 M. Whereas nanoparticles with refined morphology and shapes upon irradiation present high enhancement factors of >107 and detection limit down to 10- 9 M. In addition, uniformity in Raman spectra over the SERS substrates has been obtained for selected Ag NPs substrates synthesized using irradiated extracts with minimum relative standard deviation in enhancement factor < 12%.

Photocatalytic degradation of 2,4-dichlorophenol using nanomaterials silver halide catalysts

In this study, the photocatalytic activity of nanomaterials Ag/AgX (X = Cl, Br, I) is reported. Highly efficient silver halide (Ag/AgX where X = Cl, Br, I) photocatalysts were synthesized through a hydrothermal method. The samples were characterized using a range of techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) to check their structural, morphology, textural and optical properties. In addition, the photocatalytic activity of photocatalysts was evaluated through the degradation of 2,4-dichlorophenol (2,4-DCP) under UV and visible light irradiation. XRD analysis confirmed the presence of a single-phase structure (pure phase) in the synthesized photocatalysts. SEM micrographs showed agglomeration with a non-uniform distribution of particles, which is a characteristic of surfactant-free precipitation reactions in aqueous media. The Ag/AgBr photocatalyst exhibited the best degradation efficiency, resulting in 83.37% and 89.39% photodegradation after 5 h of UV and visible light irradiation, respectively. The effect of catalyst loading, initial solution pH, and 2,4-DCP concentration was investigated for the best-performing Ag/AgBr photocatalyst. The degradation kinetics were best described by the pseudo-first-order Langmuir-Hinshelwood model. The photocatalytic capacity of Ag/AgBr decreased by 50% after five reuse cycles. SEM images revealed heightened levels of photodegradation on the catalyst surface. The study proved the feasibility of using simple synthesis methods to produce visible light active photocatalysts capable of degrading refractory phenolic pollutants in aqueous systems.

Integrated Temperature-Humidity Sensors for a Pouch-Type Battery Using 100% Printing Process

The performance, stability, and lifespan of lithium-ion batteries are influenced by variations in the flow of lithium ions with temperature. In electric vehicles, coolants are generally used to maintain the optimal temperature of the battery, leading to an increasing demand for temperature and humidity sensors that can prevent leakage and short circuits. In this study, humidity and temperature sensors were fabricated on a pouch film of a pouch-type battery. IDE electrodes were screen-printed on the pouch film and humidity- and temperature-sensing materials were printed using a dispenser process. Changes in the capacitance of the printed Ag-CNF film were used for humidity sensing, while changes in the resistance of the printed PEDOT:PSS film were used for temperature sensing. The two sensors were integrated into a single electrode for performance evaluation. The integrated sensor exhibited a response of ΔR ≈ 0.14 to temperature variations from 20 °C to 100 °C with 20% RH humidity as a reference, and a response of ΔC ≈ 2.8 to relative humidity changes from 20% RH to 80% RH at 20 °C. The fabricated integrated sensor is expected to contribute to efficient temperature and humidity monitoring applications in various pouch-type lithium-ion batteries.

Ag-lignin hybrid nanoparticles for high-performance solar absorption in photothermal antibacterial chitosan films

There is an urgent need for antimicrobial films based on sustainable resources and production methods. In this study, we present a bio-based nanocomposite film composed of chitosan (∼60 wt %), lignin nanoparticles (LNPs, ∼40 wt %), a small amount of glutaraldehyde (1.5 wt %), and a trace level of silver nanoparticles (AgNPs, 0.072 wt %). The uniform dispersion with LNPs prevented aggregation of metallic silver, resulting in small (diameter 3.3 nm) AgNPs. The nanocomposite film absorbs 89% of radiation across the entire solar spectrum and exhibits a remarkable photothermally triggered antibacterial effect, which is further enhanced by the dark color of lignin. Under simulated solar light illumination, the nanocomposite films demonstrated a significant reduction in viable Escherichia coli count compared to control scenarios. The potential applications of these nanocomposites extend to sunlight-activated antimicrobial films and coatings, addressing the growing demand for sustainable and effective antimicrobial materials.

Ultrasensitive detection of crystal violet using a molybdenum sulfide-silver nanostructure-based sensing platform: roles of the adsorbing semiconductor in SERS signal enhancement

Crystal violet (CV) is an organic dye that is stabilized by the extensive resonance delocalization of electrons over three electron-donating amine groups. This prevents the molecule from being linked to a metal surface, and therefore, reduces the sensitivity of surface-enhanced Raman scattering (SERS) sensors for this toxic dye. In this work, we improved the sensing performance of a silver-based SERS sensor for CV detection by modifying the active substrate. Molybdenum sulfide (MoS2) nanosheets were employed as a scaffold for anchoring electrochemically synthesized silver nanoparticles (e-AgNPs) through a single step of ultrasonication, leading to the formation of MoS2/Ag nanocomposites. As an excellent adsorbent, MoS2 promoted the adsorption of CV onto the surface of the substrate, allowing more CV molecules to be able to experience the SERS effect originating from the e-AgNPs. Hence, the SERS signal of CV was significantly enhanced. In addition, the effects of the MoS2 content of the nanocomposites on their SERS performance were also taken into account. Using MoS2/Ag with the most optimal MoS2 content of 10%, the SERS sensor exhibited the best enhancement of the SERS signal of CV with an impressive detection limit of 1.17 × 10-11 M in standard water and 10-9 M in tap water thanks to an enhancement factor of 2.9 × 106, which was 11.2 times higher than that using pure e-AgNPs.

Silver Natural Asphalt Sulfonate (NA-SO3Ag): Fabrication and Utilization as a New Heterogeneous, Carbonaceous, and Retrievable Nanocatalyst for C(sp2)-X (X = C, S, and Se) Bond Formation

Silver-based catalysts are valuable catalysts in various areas of the chemical industry, organic syntheses, and transformations, and from a chemical and industrial point of view, their recycling is very important. Herein, silver natural asphalt sulfonate (NA-SO3Ag) was fabricated via the grafting of Ag(I) on the surface of the solid natural asphalt sulfonate as a novel and efficient recoverable sliver nanocatalyst. Natural asphalt is one of the hydrocarbons that are found in mineral veins. The structure of NA-SO3Ag was characterized by diverse microscopic and spectroscopic techniques including Fourier-transform infrared (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), and inductively coupled plasma optical emission spectroscopy (ICP-OES) techniques. The NA-SO3Ag nanocatalyst was utilized for C-Se and C-S bond formation via coupling reactions of aryl halides and organic disulfides/diselenides to afford a wide variety of diaryl sulfides/selenides in good to excellent yields. Additionally, the utilization of NA-SO3Ag in C-C bond formation was examined in Suzuki coupling reactions successfully. For at least 6 trials, this heterogeneous catalyst can be separated and reused without any activity reduction.

Sub-second synthesis of silver nanoparticles in 3D printed monolithic multilayered microfluidic chip: Enhanced chemiluminescence sensing predictions via machine learning algorithms

Futuristic microfluidics will require alternative ways to extend its potential in vast areas by integrating various facets such as automation of different subsystems, multiplexing, incorporation of cyber-physical capabilities, and rapid prototyping. On the rapid prototyping aspect, for the last decade, additive manufacturing (AM) or 3D printing (3DP) has advanced to become an alternative fabrication process for microfluidic devices, enabling industry-level abilities towards mass production. In this context, for the first time, this work demonstrates the fabrication of monolithic multilayer microfluidic devices (MMMD) from planar orientation (1 layer) to nonplanar (4 layers) monolithic microchannels. The developed MMM device was impeccable for synthesizing highly potentialized silver nanoparticles (AgNPs) in <1 s. Moreover, the transport of chemical species with laminar flow simulations was performed on the process along with the thorough characterizations of produced AgNPs, finding the mean AgNPs particle size of around 35 nm without any post-processing requirements. The well-known catalytic activity of AgNPs was leveraged to enhance weak chemiluminescence (CL) sensing signals by >1300 %, increasing CL sensitivity. Further, machine learning (ML) predictive models encouraged to obtain the experimental parameters without human intervention iterations for target-specific applications. The proposed methodology finds the potential to save resources, time, and enables automation with rapid prototyping, providing possibilities for mass fabrications.

Electrospun Nanofibers from Waste Polyvinyl Chloride Loaded Silver and Titanium Dioxide for Water Treatment Applications

The electrospun nanofiber membrane from polyvinyl chloride (PVC) waste for water treatment applications has been successfully produced. The PVC precursor solution was prepared by dissolving the PVC waste in DMAc solvent, and a centrifuge was used to separate undissolved materials from the precursor solution. Ag and TiO₂ were added to the precursor solution before the electrospinning process. We studied the fabricated PVC membranes using SEM, EDS, XRF, XRD, and FTIR to study the fiber and membrane properties. The SEM images depicted that Ag and TiO₂ addition has changed the morphology and size of fibers. The EDS images and XRF spectra confirmed the presence of Ag and TiO₂ on the nanofiber membrane. The XRD spectra showed the amorphous structure of all membranes. The FTIR result indicated that the solvent completely evaporated throughout the spinning process. The fabricated PVC@Ag/TiO₂ nanofiber membrane showed the photocatalytic degradation of dyes under visible light. The filtration test on the membrane PVC and PVC@Ag/TiO₂ depicted that the presence of Ag and TiO₂ affected the flux and separation factor of the membrane.

Application of Red Onion Peel Extract for Green Synthesis of Silver Nanoparticles in Hydrogels Exhibiting Antimicrobial Properties

UV-initiated green synthesis of metal nanoparticles by using plant extracts as photoreducing agents is of particular interest since it is an environmentally friendly, easy-to-maintain, and cost-effective method. Plant molecules that act as reducing agents are assembled in a highly controlled way which makes them suitable for metal nanoparticle synthesis. Depending on the plant species, their application for green synthesis of metal nanoparticles for diverse applications may contribute to the mediation/reduction in organic waste amounts, thus enabling the implementation of the circular economy concept. In this work, UV-initiated green synthesis of Ag nanoparticles in hydrogels and hydrogel's thin films containing gelatin (matrix), red onion peel extract of different concentrations, water, and a small amount of 1 M AgNO₃ have been investigated and characterized using UV-Vis spectroscopy, SEM and EDS analysis, XRD technique, performing swelling experiments and antimicrobial tests using bacteria (Staphylococcus aureus, Acinetobacter baumannii, Pseudomonas aeruginosa), yeasts (Candida parapsilosis, Candida albicans) and microscopic fungi (Aspergillus flavus, Aspergillus fumigatus). It was found that the antimicrobial effectiveness of the silver-enriched red onion peel extract-gelatin films was higher at lower AgNO₃ concentrations as compared to those usually used in the commercially available antimicrobial products. The enhancement of the antimicrobial effectiveness was analyzed and discussed, assuming the synergy between photoreducing agent (red onion peel extract) and silver nitrate (AgNO₃) in the initial gel solutions leading to the intensification of Ag nanoparticles production.

Ag2O-adorned ZnO nanostructures: cooperative and sustainable nanomaterial system for effective reduction and mineralization of hazardous water pollutants

Organic water pollutants like nitroaromatics and synthetic dyes are causing serious threats to water. Ever-growing urban and industrial activities along with population explosion are rapidly contributing severe level of water contamination. Semiconducting nanomaterial-based photocatalysis has been proven to be an effective process for degradation of organic water pollutants. In the current study, visible light active Ag₂O-adorned ZnO nanostructures were fabricated by a simple two-step hydrothermal method and the prepared nanostructures were utilized for the photocatalytic mineralization of rhodamine B (RhB) dye with visible light radiation. The catalytic potential of as-synthesized nanostructures was also investigated for the reduction of nitroaromatics (4-NP and 4-NA) and RhB dye in the presence of NaBH₄. The Ag₂O-adorned ZnO nanostructures prepared with 5% of silver nitrate denoted as ZnO/Ag₂O (5%) demonstrated stupendous photomineralization activity against RhB dye as almost 100% degradation of RhB dye was achieved within 100 min of reaction time at pH = 6. The kinetic study revealed that the degradation reaction followed the pseudo-first-order kinetics and the kinetic rate constant (k) of photodecolorization reaction for optimal catalyst was calculated to be 61.4 × 10^-3 min^-1. The nanostructures revealed excellent recyclability and photostability as 95% activity of the catalyst was preserved even after the fifth cyclic run. The catalytic reduction of the 4-NP, 4-NA, and RhB dye was completed in 21, 12, and 40 min, respectively, in the presence of ZnO/Ag₂O (5%) and NaBH₄ solution. The kinetic rate constant values for the reduction reactions were determined to be 229.6 × 10^-3, 454.2 × 10^-3, and 105.5 × 10^-3 min^-1 for 4-NP, 4-NA, and RhB dye, respectively. Thus, the obtained results suggest that the components of the prepared nanosystem help in mutually strengthening the catalytic and photocatalytic abilities of each other, indicating the development of a cooperative and sustainable nanomaterial system in the current study.

Biosynthesis of Silver Nanoparticles and Exploring Their Potential of Reducing the Contamination of the In Vitro Culture Media and Inducing the Callus Growth of Rumex nervosus Explants

Among biological methods, green synthesis of the nanomaterials using plant extracts was shown to be an environmentally friendly, economical, and simple approach. In the current study, the biogenic synthesis of silver nanoparticles (AgNPs) was achieved using the leaf extract of Hibiscus tiliaceus, in order to prevent the contamination of the tissue culture media and induce callus growth. The nanostructures of the fabricated AgNPs were characterized using UV-visible spectroscopy, Fourier transform infra-red spectra (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), zeta size, and zeta potential techniques. Our results indicate that The UV-vis spectrum of AgNPs exhibited an absorption band at 415 nm. The FTIR analysis identified the functional groups which could involve in the reduction of silver ions to AgNPs, this was also confirmed by the (hkl) diffraction peaks in the XRD diffractogram. Moreover, the TEM analysis showed a spherical nanoparticle with a size ranging from 21 and 26 nm. Thereafter, the potential antibacterial and antifungal activity of the biogenic AgNPs was evaluated against Bacillus pumilus and Alternaria alternata which were isolated from the in vitro culture media and identified based on 16S rDNA and ITS rDNA sequences, respectively. The results showed that the AgNPs significantly inhibited the growth of Alternaria alternata and Bacillus pumilus at all applied concentrations (5, 10, 20 and 40 mg/L). Compared to the control more fungal radial growth reduction (42.59%,) and bacterial inhibition (98.12%) were registered in the plates containing high doses of AgNPs (40 mg/L). Using Rumex nervosus explants, the biosynthesized AgNPs were tested for their impact to promote callus growth. The obtained results showed a significant effect of AgNPs on callus fresh weight at all applied doses. Moreover, AgNPs treatments showed a polymorphism of 12.5% which was detected by RAPD markers. In summary, the results revealed that AgNPs (40 mg/L) can be effectively added to the in vitro culture media for reducing microbial contamination and improving callus growth while greatly maintaining its genetic stability.

Reductive Oligomerization of Nitroaniline Catalyzed by Fe3O4 Spheres Decorated with Group 11 Metal Nanoparticles

The present work demonstrates a simple and sustainable method for forming azo oligomers from low-value compounds such as nitroaniline. The reductive oligomerization of 4-nitroaniline was achieved via azo bonding using nanometric Fe₃O₄ spheres doped with metallic nanoparticles (Cu NPs, Ag NPs, and Au NPs), which were characterized by different analytical methods. The magnetic saturation (M _s) of the samples showed that they are magnetically recoverable from aqueous environments. The effective reduction of nitroaniline followed pseudo-first-order kinetics, reaching a maximum conversion of about 97%. Fe₃O₄-Au is the best catalyst, its a reaction rate (k _Fe3O4-Au = 0.416 mM L^-1 min^-1) is about 20 times higher than that of bare Fe₃O₄ (k _Fe3O4 = 0.018 mM L^-1 min^-1). The formation of the two main products was determined by high-performance liquid chromatography-mass spectrometry (HPLC-MS), evidencing the effective oligomerization of NA through N = N azo linkage. It is consistent with the total carbon balance and the structural analysis by density functional theory (DFT)-based total energy. The first product, a six-unit azo oligomer, was formed at the beginning of the reaction through a shorter, two-unit molecule. The nitroaniline reduction is controllable and thermodynamically viable, as shown in the computational studies.

Development of Sustainable Hydrophilic Azadirachta indica Loaded PVA Nanomembranes for Cosmetic Facemask Applications

Nanofiber-based facial masks have attracted the attention of modern cosmetic applications due to their controlled drug release, biocompatibility, and better efficiency. In this work, Azadirachta indica extract (AI) incorporated electrospun polyvinyl alcohol (PVA) nanofiber membrane was prepared to obtain a sustainable and hydrophilic facial mask. The electrospun AI incorporated PVA nanofiber membranes were characterized by scanning electron microscope, Ultraviolet-visible spectroscopy (UV-Vis) drug release, water absorption analysis, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging, and antibacterial activity (qualitative and quantitative) at different PVA and AI concentrations. The optimized nanofiber of 376 ± 75 nm diameter was obtained at 8 wt/wt% PVA concentration and 100% AI extract. The AI nanoparticles of size range 50~250 nm in the extract were examined through a zeta sizer. The water absorption rate of ~660% and 17.24° water contact angle shows good hydrophilic nature and water absorbency of the nanofiber membrane. The UV-Vis also analyzed fast drug release of >70% in 5 min. The prepared membrane also exhibits 99.9% antibacterial activity against Staphylococcus aureus and has 79% antioxidant activity. Moreover, the membrane also had good mechanical properties (tensile strength 1.67 N, elongation 48%) and breathability (air permeability 15.24 mm/s). AI-incorporated nanofiber membrane can effectively be used for facial mask application.

Bioactive Carboxymethyl Cellulose (CMC)-Based Films Modified with Melanin and Silver Nanoparticles (AgNPs)-The Effect of the Degree of CMC Substitution on the In Situ Synthesis of AgNPs and Films' Functional Properties

Green synthesis of nanoparticles for use in food packaging or biomedical applications is attracting increasing interest. In this study, the effect of the degree of substitution (0.7, 0.9 and 1.2) of a carboxymethylcellulose polymer matrix on the synthesis and properties of silver nanoparticles using melanin as a reductant was investigated. For this purpose, the mechanical, UV-Vis barrier, crystallinity, morphology, antioxidant and antimicrobial properties of the films were determined, as well as the color and changes in chemical bonds. The degree of substitution effected noticeable changes in the color of the films (the L* parameter was 2.87 ± 0.76, 5.59 ± 1.30 and 13.45 ± 1.11 for CMC 0.7 + Ag, CMC 0.9 + Ag and CMC 1.2 + Ag samples, respectively), the UV-Vis barrier properties (the transmittance at 280 nm was 4.51 ± 0.58, 7.65 ± 0.84 and 7.98 ± 0.75 for CMC 0.7 + Ag, CMC 0.9 + Ag and CMC 1.2 + Ag, respectively) or the antimicrobial properties of the films (the higher the degree of substitution, the better the antimicrobial properties of the silver nanoparticle-modified films). The differences in the properties of films with silver nanoparticles synthesized in situ might be linked to the increasing dispersion of silver nanoparticles as the degree of CMC substitution increases. Potentially, such films could be used in food packaging or biomedical applications.

Green Synthesis of Hexagonal Silver Nanoparticles Using a Novel Microalgae Coelastrella aeroterrestrica Strain BA_Chlo4 and Resulting Anticancer, Antibacterial, and Antioxidant Activities

Microalgae-mediated synthesis of nanoparticles (NPs) is an emerging nanobiotechnology that utilizes the biomolecular corona of microalgae as reducing and capping agents for NP fabrication. This study screened a novel microalgal strain for its potential to synthesize silver (Ag)-NPs and then assayed the biological activities of the NPs. Coelastrella aeroterrestrica strain BA_Chlo4 was isolated, purified, and morphologically and molecularly identified. Chemical composition of the algal extract was determined by GC-MS analysis. Ag-NPs were biosynthesized by C. aeroterrestrica BA_Chlo4 (C@Ag-NPs) and characterized using various techniques. Antiproliferative activity and the biocidal effect of C@Ag-NPs, C. aeroterrestrica algal extract, and chemically synthesized Ag-NPs (Ch@Ag-NPs) were explored, and the scavenging activity of C@Ag-NPs against free radicals was investigated. C@Ag-NPs were hexagonal, with a nanosize diameter of 14.5 ± 0.5 nm and a maximum wavelength at 404.5 nm. FTIR and GC-MS analysis demonstrated that proteins and polysaccharide acted as capping and reducing agents for C@Ag-NPs. X-ray diffraction, energy diffraction X-ray, and mapping confirmed the crystallinity and natural structure of C@Ag-NPs. The hydrodynamic diameter and charge of C@Ag-NPs was 28.5 nm and −33 mV, respectively. C@Ag-NPs showed significant anticancer activity towards malignant cells, with low toxicity against non-cancerous cells. In addition, C@Ag-NPs exhibited greater antioxidant activity and inhibitory effects against Gram-positive and -negative bacteria compared with the other tested treatments. These findings demonstrate, for first time, the potential of a novel strain of C. aeroterrestrica to synthesize Ag-NPs and the potent antioxidant, anticancer, and biocidal activities of these NPs.

The Sensitization of TiO2 Thin Film by Ag Nanoparticles for the Improvement of Photocatalytic Efficiency

The formation of Ag nanoparticles on the surface of TiO2 (AgNP/TiO2) to enhance photocatalytic efficiency was studied. The Ag nanoparticles (AgNP) size, form, and distribution dependence on the initial thickness of Ag thin films, annealing temperature, and time were analyzed. The optimal annealing temperature of 400 °C and annealing time of 60 min were chosen to form AgNP from the initial Ag thin films with a thickness of 5, 7.5, and 10 nm. The formation of AgNP was done on amorphous TiO2 (a-TiO2), which crystallized into the anatase phase after the annealing. The photocatalytic efficiency (k–degradation rate constant, Defi–degradation efficiency) was evaluated by the photodegradation of Rhodamine B aqueous solution. The results suggested that the highest photocatalytic efficiency of Rhodamine B aqueous solution was reached where the average diameter (DA) of AgNP was ~38 nm (k38 = 0.017 min−1, Defi_38 = 63.5%), compared to 27 and 82 nm (k27 = 0.012 min−1, Defi_27 = 51.2% and k82 = 0.011 min−1, Defi_82 = 52.1%, respectively). The acquired results did not show clear correlation between the size and distribution of the AgNP on the TiO2 surface and photocatalytic efficiency. Nevertheless, the results suggest that AgNP can enhance the photocatalytic efficiency of TiO2 thin films (kTiO2 = 0.008 min−1, Defi_TiO2 = 36.3%).

Synthesis of silver and gold nanoparticles-enzyme-polymer conjugate hybrids as dual-activity catalysts for chemoenzymatic cascade reactions

Novel hybrids containing silver or gold nanoparticles have been synthesized in aqueous media and at room temperature using enzymes or tailor-made enzyme-polymer conjugates, which directly induced the formation of inorganic silver or gold species. The choice of pH, protein, or bioconjugate strongly affected the final metallic nanoparticles hybrid formation. Using Candida antarctica lipase (CALB) in a solution, nanobiohybrids containing Ag₂O nanoparticles of 9 nm average diameter were obtained. The use of tailor-made bioconjugates, for example, the CALB modified with dextran-aspartic acid polymer (Dext6kDa), resulted in a nanobiohybrid containing smaller Ag(0)/Ag₂O nanoparticles. In the case of nanobiohybrids based on gold, Au(0) species were found in all cases. The Au-CALB hybrid contained spherical nanoparticles with 18 nm average diameter size, with a minor range of larger ones (>100 nm) while the AuNPs-CALB-Dext6kDa hybrid was formed by much smaller nanoparticles (9 nm, minor range of 22 nm), and also nanorods of 20-30/40-50 nm length. Using Thermomyces lanuginosus lipase (TLL), apart from the nanoparticle formation, nanoflowers with a diameter range of 100-200 nm were obtained. All nanobiohybrids maintained (dual) enzymatic and metallic activities. For instance, these nanobiohybrids exhibited exquisite dual-activity for hydrolysis/cycloisomerization cascades starting from allenic acetates. By merging the transition metal reactivity with the inherent lipase catalysis, allenic acetates directly converted to the corresponding O-heterocycles in enantiopure form catalysed by AgNPs-CALB-Dext6kDa, taking advantage of a kinetic resolution/cyclization pathway. These results showed the high applicability of these novel hybrids, offering new opportunities for the design of novel reaction cascades.

Green-Synthesized Silver Nanoparticle-Assisted Radiofrequency Ablation for Improved Thermal Treatment Distribution

Thermal ablation therapy is known as an advantageous alternative to surgery allowing the treatment of multiple tumors located in hard-to-reach locations or treating patients with medical conditions that are not compatible with surgery. Appropriate heat propagation and precise control over the heat propagation is considered a weak point of thermal ablation therapy. In this work, silver nanoparticles (AgNPs) are used to improve the heat propagation properties during the thermal ablation procedure. Green-synthesized silver nanoparticles offer several attractive features, such as excellent thermal conductivity, biocompatibility, and antimicrobial activity. A distributed multiplexed fiber optic sensing system is used to monitor precisely the temperature change during nanoparticle-assisted radiofrequency ablation. An array of six MgO-based nanoparticles doped optical fibers spliced to single-mode fibers allowed us to obtain the two-dimensional thermal maps in a real time employing optical backscattering reflectometry at 2 mm resolution and 120 sensing points. The silver nanoparticles at 5, 10, and 20 mg/mL were employed to investigate their heating effects at several positions on the tissue regarding the active electrode. In addition, the pristine tissue and tissue treated with agarose solution were also tested for reference purposes. The results demonstrated that silver nanoparticles could increase the temperature during thermal therapies by propagating the heat. The highest temperature increase was obtained for 5 mg/mL silver nanoparticles introduced to the area close to the electrode with a 102% increase of the ablated area compared to the pristine tissue.

Synthesis and Characterization of PdAgNi/C Trimetallic Nanoparticles for Ethanol Electrooxidation

The direct use of ethanol in fuel cells presents unprecedented economic, technical, and environmental opportunities in energy conversion. However, complex challenges need to be resolved. For instance, ethanol oxidation reaction (EOR) requires breaking the rigid C–C bond and results in the generation of poisoning carbonaceous species. Therefore, new designs of the catalyst electrode are necessary. In this work, two trimetallic Pd_xAg_yNi_z/C samples are prepared using a facile borohydride reduction route. The catalysts are characterized by X-ray diffraction (XRD), Energy-Dispersive X-ray spectroscopy (EDX), X-ray photoelectron Spectroscopy (XPS), and Transmission Electron Microscopy (TEM) and evaluated for EOR through cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). The XRD patterns have shown a weak alloying potential between Pd, and Ag prepared through co-reduction technique. The catalysts prepared have generally shown enhanced performance compared to previously reported ones, suggesting that the applied synthesis may be suitable for catalyst mass production. Moreover, the addition of Ag and Ni has improved the Pd physiochemical properties and electrocatalytic performance towards EOR in addition to reducing cell fabrication costs. In addition to containing less Pd, The PdAgNi/C is the higher performing of the two trimetallic samples presenting a 2.7 A/mg_Pd oxidation current peak. The Pd₄Ag₂Ni₁/C is higher performing in terms of its steady-state current density and electrochemical active surface area.

Targeted Delivery of Colloidal Silver for MCF-7 Breast Cancer Treatment

BACKGROUND

Amongst various cancer diseases, breast cancer is frequently diagnosed malignancy in women. Existing treatments are inadequate, painful and toxic. New ways of treatments need to be explored.

METHODS

The present work proposes preparation and targeted delivery of a formulation, F-1, for MCF-7 breast cancer treatment. The formulation, colloidal silver (0.76 ppm), was prepared by electrolytic deposition technique and multi surface coatings. Black tea extract (2.25%v/v) was used as a capping agent to tune the morphology of silver nanoparticle and potato extract (6.25%v/v) as a functionalizing agent for targeting MCF-7 breast cancer site.

RESULTS

Characterization results show highly pure spherical silver nanoparticles with an average particle size of 15nm. The shift of peaks in the FTIR spectra of formulation confirms the interaction between nanoparticles and extracts. The UV-visible peak was obtained at 525nm, a typical characteristic of silver nanoparticles. In-vivo; anti-cancer study of formulation gave a moderate therapeutic effect in Non-Obese Diabetic Severe Combined Immune Deficiency (NOD-SCID) mice.

CONCLUSION

It is observed that tumor volumes obtained in the case of Formulation-1 were moderately inhibited from days 5 to 9. However, one of the mice in the Formulation-1 group inhibited tumor volume to 1.52 cc similar to one of the mice of positive control group (Adriamycin 1.42cc).

Green Synthesized of Ag/Ag2O Nanoparticles Using Aqueous Leaves Extracts of Phoenix dactylifera L. and Their Azo Dye Photodegradation

In this study, silver/silver oxide nanoparticles (Ag/Ag2O NPs) were successfully biosynthesized using Phoenix dactylifera L. aqueous leaves extract. The effect of different plant extract/precursor contractions (volume ratio, v/v%) on Ag/Ag2O NP formation, their optical properties, and photocatalytic activity towards azo dye degradation, i.e., Congo red (CR) and methylene blue (MB), were investigated. X-ray diffraction confirmed the crystalline nature of Ag/Ag2O NPs with a crystallite size range from 28 to 39 nm. Scanning electron microscope images showed that the Ag/Ag2O NPs have an oval and spherical shape. UV-vis spectroscopy showed that Ag/Ag2O NPs have a direct bandgap of 2.07-2.86 eV and an indirect bandgap of 1.60-1.76 eV. Fourier transform infrared analysis suggests that the synthesized Ag/Ag2O NPs might be stabilized through the interactions of -OH and C=O groups in the carbohydrates, flavonoids, tannins, and phenolic acids present in Phoenix dactylifera L. Interestingly, the prepared Ag/Ag2O NPs showed high catalytic degradation activity for CR dye. The photocatalytic degradation of the azo dye was monitored spectrophotometrically in a wavelength range of 250-900 nm, and a high decolorization efficiency (84.50%) was obtained after 50 min of reaction. As a result, the use of Phoenix dactylifera L. aqueous leaves extract offers a cost-effective and eco-friendly method.

Assessment and treatment of floodwater in the Vietnamese Mekong Delta using a simple filter system based on silver nanoparticles coated onto activated carbon derived from rice husk

The floods in the Vietnamese Mekong Delta have long caused a shortage of clean water supply, which has a significant impact on the indigenous people in the region. We have conducted a preliminary survey of the water quality of the Hau Giang River (one of the two main branches of the Mekong River) before, during, and after the flood season. The obtained results demonstrated that the water in the Hau Giang River was highly turbid and contaminated with a large number of harmful microorganisms. Thus, in this study, a simple filter system based on silver nanoparticles coated onto activated carbon derived from rice husk (AgNPs@AC) has been proposed for treating floodwater from the Hau Giang River. The optimal conditions for AgNPs@AC preparation were established. The prepared AgNPs@AC was then characterized using various surface analyses such as SEM, TEM, XRD, BET, FTIR, and DLS. The initial floodwater source would be pre-treated with polyaluminum chloride using the coagulation–sedimentation method to remove the suspended solids before being discharged into the filtration column containing AgNPs@AC. The results showed that the filter system based on AgNPs@AC performed well in removing turbidity, dissolved solids, suspended solids, color, and bacteria from the floodwater. In addition, it was determined that the filter column with a 30 mm thick AgNPs@AC layer could continuously process 1300 m³ of the floodwater and had a service life of more than two months. The findings of this study not only added to our understanding of the floodwater treatment capacity of activated carbon coated nanoparticles, but they also provided valuable information for water treatment plants along the Hau Giang River, aquatic ecosystem researchers, and public health researchers.

In this study, a simple filter system based on silver nanoparticles coated onto activated carbon derived from rice husk (AgNPs@AC) has been proposed for treating floodwater from the Hau Giang River.

Intrinsic Peroxidase-Mimicking Ir Nanoplates for Nanozymatic Anticancer and Antibacterial Treatment

The study of inorganic nanozymes to overcome the disadvantages of bio-enzymes, such as the requirement of optimized reaction conditions and lack of durability against environmental factors, is one of the most significant research topics at present. In this work, we comprehensively analyzed the intrinsic peroxidase-like activity of Ir-based nanoparticles, the biological and nanozymatic potentials of which have not yet been explored. These particles were synthesized by the galvanic replacement of Ag nanoplates with Ir. Through the confirmed peroxidase-like activity and hydrogen peroxide decomposition with free radical generation facilitated by these particles, the antibacterial and anticancer effects were successfully verified in vitro. The nanozyme-based therapeutic effect observed at concentrations at which these nanoparticles do not show cytotoxicity suggests that it is possible to achieve more precise and selective local treatment with these particles. The observed highly efficient peroxidase-like activity of these nanoparticles is attributed to the partially mixed composition of Ir-Ag-IrO₂ formed through the galvanic replacement reaction in the synthetic process.

Conjugation of micro/nanocurcumin particles to ZnO nanoparticles changes the surface charge and hydrodynamic size thereby enhancing its antibacterial activity against Escherichia coli and Staphylococcus aureus

Nanobiotechnology-mediated synthesis of ZnO nanoparticles, micro/nanocurcumin, and curcumin-ZnO nanocomposites and their characterization followed by comparative study of their antibacterial, antioxidant, and iron-chelating efficiency at various dosages are discussed. Micro/nanocurcumin and ZnO nanoparticles were synthesized using curcumin and zinc nitrate as precursor and then conjugated by sonication to synthesize curcumin-ZnO nanocomposites. The synthesized nanoparticles were then characterized by using ultraviolet-visible spectroscopy, X-ray diffraction, Scanning electron microscopy, Fourier-transform infrared spectroscopy, and dynamic light scattering analysis. After that, the antibacterial activity of the synthesized nanoparticles was evaluated by the optical density (OD₆₀₀ ) method against Escherichia coli and Staphylococcus aureus cells. The DPPH (2,2-diphenyl-1-picrylhydrazyl ), hydroxyl radical scavenging activity, and ferrous ion-chelating efficiency of synthesized nanoparticles were evaluated by spectrophotometry analysis. Nanocurcumin (mean zeta potential = -25 mV; average hydrodynamic diameter = 410 nm) based coating of ZnO nanoparticles (mean zeta potential = -15.9 mV; average hydrodynamic diameter = 274 nm) to synthesize curcumin-ZnO nanocomposites (mean zeta potential = -18.8 mV; average hydrodynamic diameter = 224 nm) exhibited enhanced zeta potential, which resulted in reduced agglomeration, smaller hydrodynamic size in water, improved aqueous solubility, and dispersion. All the aforesaid factors including the synergistic antibacterial effect of ZnO nanoparticle and micro/nanocurcumin contributed to increased antibacterial efficiency of curcumin-ZnO nanocomposites. Micro/nanocurcumin due to its better water solubility and small hydrodynamic diameter exhibited enhanced antioxidant and ferrous ion-chelating efficiency than curcumin.

Green Synthesis of an Activated Carbon-Supported Ag and ZnO Nanocomposite for Photocatalytic Degradation and Its Antibacterial Activities

In this study Ag nanoparticles (AgNPs), ZnO nanoparticles (ZnONPs), and Ag/ZnO nanocomposites were greenly synthesized and loaded on activated carbon via three different routes: simple impregnation, successive precipitation, and co-precipitation. Neem leaf extract was used as a reducing and stabilizing agent. The morphological and structural properties of the synthesized nanocomposites have been examined using different analytical techniques such as XRD, SEM, FTIR, and UV. The antibacterial and catalytic activity of the synthesized nanocomposites were examined and compared. The results showed that AgNPs loaded on activated carbon (Ag/AC) has the best catalytic activity compared to the other nanocomposites, which is attributed to the good dispersal of AgNPs on the surface of activated carbon. Furthermore, AgNPs showed the best antibacterial effect on eight out of 16 tested pathogens. Results also showed that the order of precipitation is an important factor, as both antibacterial activities and photodegradation activities were higher for ZnO/Ag/AC than Ag/ZnO/AC. Furthermore, the co-precipitation method was shown to be better than the successive precipitation method for 4-nitrophenol photodegradation and 14 out of the 16 antibacterial tests performed.

Hierarchically Designed Ag@Ce6Mo10O39 Marigold Flower-Like Architectures: An Efficient Electrode Material for Hybrid Supercapacitors

We facilely prepared silver nanoparticle-decorated Ce₆Mo₁₀O₃₉ marigold flower-like structures (Ag NPs@CM MFs) for use as an effective positive material in hybrid supercapacitors (HSCs). With the aid of ethylenediaminetetraacetic acid (EDTA) as a chelating agent, self-assembled CM MFs were synthesized by a single-step hydrothermal method. When the electrochemical properties were tested in an aqueous alkaline electrolyte, the synthesized CM MFs with 0.15 g of EDTA exhibited a relatively high charge storage property (55.3 μA h/cm² at 2 mA/cm²) with a battery-type redox behavior. The high capacity performance is mainly because of the large surface area of the CM MFs, and the hierarchically connected nanoflakes provide wide open wells for rapid accessibility of electrolyte ions and enable fast transportation of electrons. A further improvement in electrochemical performance was achieved (62 μA h/cm² at 2 mA/cm²) by decorating Ag NPs on the surface of the CM MFs (i.e., Ag NPs@CM MFs), which is attributed to the increased electric conductivity. Considering the synergistic effect and the high electrochemical activity, Ag NPs@CM MFs were further employed as an effective positive electrode for the fabrication of pouch-type HSC with porous carbon (negative electrode) in an alkaline electrolyte. The HSC exhibited a high cell potential (1.5 V) with maximum energy and power densities of 0.0183 mW h/cm² and 10.237 mW/cm², respectively. The potency of HSC in practical applications was also demonstrated by energizing red and yellow light-emitting diodes as well as a three-point pattern torch light.

Biosynthesis, Characterization, and Bioactivities Evaluation of Silver and Gold Nanoparticles Mediated by the Roots of Chinese Herbal Angelica pubescens Maxim

A facile synthesis and biological applications of silver (DH-AgNps) and gold nanoparticles (DH-AuNps) mediated by the aqueous extract of Angelicae Pubescentis Radix (Du Huo) are explored. Du Huo is a medicinal root belonging to Angelica pubescens Maxim which possesses anti-inflammatory, analgesic, and antioxidant properties. The absorption spectra of nanoparticles in varying root extract and metal ion concentration, pH, reaction temperatures, and time were recorded by ultraviolet-visible (UV-Vis) spectroscopy. The presence of DH-AgNps and DH-AuNps was confirmed from the surface plasmon resonance intensified at ~414 and ~540 nm, respectively. Field emission transmission electron micrograph (FE-TEM) analysis revealed the formation of quasi-spherical DH-AgNps and spherical icosahedral DH-AuNps. These novel DH-AgNps and DH-AuNps maintained an average crystallite size of 12.48 and 7.44 nm, respectively. The biosynthesized DH-AgNps and DH-AuNps exhibited antioxidant activity against 2,2-diphenyl-1-picrylhydrzyl (DPPH) radicals and the former exhibited antimicrobial activity against clinical pathogens including Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella enterica. The expected presence of flavonoids, sesquiterpenes, and phenols on the nanoparticle surface were conjectured to grant protection against aggregation and free radical scavenging activity. DH-AgNps and DH-AuNps were further investigated for their cytotoxic properties in RAW264.7 macrophages for their potential application as drug carriers to sites of inflammation. In conclusion, this green synthesis is favorable for the advancement of plant mediated nano-carriers in drug delivery systems, cancer diagnostic, and medical imaging. Schematic diagram of biosynthesis of DH-AgNps and DH-AuNps and evaluation of their bioactivities.

Nano silver-embedded electrospun nanofiber of poly(4-chloro-3-methylphenyl methacrylate): use as water sanitizer

Water contaminated with microorganisms causes numerous diseases and is a major concern for public health. In search of a simple material which can provide clean water free from pathogens, nanofibers of poly(4-chloro-3-methylphenyl methacrylate, abbreviated as CMPMA, and nano Ag-doped poly(CMPMA) composite nanofibers were used to decontaminate water from microorganisms such as Escherichia coli and Bacillus subtilis. Nanofibers were prepared by electrospinning. X-ray diffraction (XRD) and transmission electron microscopy (TEM) provide the diameters of the Ag nanoparticles which are in the range 18-21 and 13-18 nm. The diameter of the poly(CMPMA) and nano Ag-doped poly(CMPMA) composite nanofiber is seen to vary between 400 and 700 nm with the change of the processing parameters. Optimum parameters for uniform nanofibers have been obtained. The morphology of the fibers is derived from scanning electron microscopy (SEM). The superiority of the nano Ag-doped poly(CMPMA) composite nanofiber was established.

One-step fabrication and characterization of a poly(vinyl alcohol)/silver hybrid nanofiber mat by electrospinning for multifunctional applications

Preparation and application of a poly(vinyl alcohol)/silver hybrid nanofiber mat by electrospinning.