Quasi-spherical Nanoparticles Research Articles

Innovative grey water treatment using eco-friendly bio-photocatalyst AgCuFe2O4@chitosan in the presence of synergistic effects of persulfate activation: optimization and mechanisms.

In this study, AgCuFe2O4@Chitosan bio-photocatalyst was synthesized to make the most of environmental benignity and chemical stability for advanced greywater applications. The photocatalyst was evaluated under UV irradiation by synergistic activation of persulfate. FESEM, EDS-Mapping, and BET analyses showed quasi-spherical nanoparticles with a homogeneous size distribution, homogenous elements dispersion, and 15.305 m2/g surface area. XRD analysis confirmed that Ag and Cu were effectively incorporated into the chitosan matrix, which increased its crystallinity and stability. The photocatalyst showed a good magnetic property with an Ms. value equal to 17.13 emu/g, which helped in its easy retrieval and reuse. The TGA analysis demonstrated that the bio-composite had high thermal stability up to 600 °C. The optimal treatment conditions were a pH of 3, 2 mM persulfate, and 0.8 g/L photocatalyst dosage, where COD removal efficiencies were 82.9 % and 73.7 %, for synthetic and natural greywater, correspondingly. During the degradation process, greywater followed a pseudo-first-order kinetic model, where both sulfate and hydroxyl radicals played key roles in the elimination of COD. Moreover, the bio-photocatalyst was very reusable up to more than a few runs of treatment cycles with very good performance, underpinning the possible applications in the greywater treatment process in a sustainable manner.

Eu3+- activated Sr2GdF7 colloid and nano-powder for horticulture LED applications

A series of multifunctional Sr2Gd1-xEuxF7 (x = 0, 0.05, 0.10, 0.40, 0.60. 0.80, and 1.00) phosphors in stable colloidal form and as nanopowders have been prepared using a hydrothermal method. Powder X-ray diffraction analysis confirmed that the materials crystallize in a cubic crystal structure. Transmission electron microscopy shows quasi-spherical nanoparticles with an average particle size of ∼24 nm. Photoluminescence measurements show highly efficient red emission in both colloids and nanopowders, with intensity continually increasing up to 80 mol% of Eu3+ content without concentration quenching. The most prominent emission peaks are around 600 nm (orange/red) and 700 nm (deep red), with the latter more pronounced. Quantum efficiency follows a similar trend, and reaches 60 % for the sample with 80 mol% of Eu3+ content. In addition, similar asymmetry ratio values and CIE coordinates show that there is not a big change in the local symmetry around Eu3+ ions or emission color across the series. This confirms that Eu3+ resides in the same crystalline environment in samples. The observed 5D0-level lifetimes gradually decrease from 12.0 ms to 6.9 ms as the Eu3+ concentration increases. Judd-Ofelt parameters show slight variation with Eu3+ concentration with Ω4 always larger than Ω2. The temperature-dependent steady-state and time-resolved photoluminescence measurements demonstrate high stability of nanopowders’ emission up to 100 °C. The combination of temperature stability and high efficiency of emission, as well as the untypical dominant deep-red emission at 700 nm labels these nanoparticles as potential nanophosphors for various applications.

Rosuvastatin/calcium carbonate co-precipitated nanoparticles: A novel synergistic approach enhancing local bone regeneration in osteoporotic rat model

This study aimed at preparing sustained release rosuvastatin (Ru) calcium carbonate (CC) co-precipitate nano-formulation for local intra-osseous application in osteoporotic rats. Nano-formulations were prepared by the co-precipitation method using different concentrations of polyvinyl alcohol (PVA) (0.2, 0.4, 0.6 %) as a stabilizer and equimolar ratios of calcium chloride and calcium carbonate (0.1, 0.3 or 0.5 M). Pre-formulation examination including; FTIR and X-ray diffraction confirmed the formation of CC nanoparticles in a crystalline structure that was preserved before and after loading with Ru. The optimized formula showing; PS of 105.71 ± 5.10 nm, PDI of 0.25 ± 0.02, ZP of −44.70 ± 0.09 mV, % EE of 60.16 ± 1.58 and a quasi-spherical nanoparticle with nano-deposition of Ru crystals adsorbed on them as seen under TEM and SEM, was then integrated in 20 % Pluronic gel. The Ru-gel exhibited good rheological behavior with a short gelation time of 20 sec and a sustained release pattern of 30 % for the optimized Ru/CC gel versus ≈ 90 % for the Ru/CC dispersion after 6 h. In-vivo, ovariectomy-induced osteoporotic rats were used to cause a bone defect in the tibial metaphysis. The drill-hole defects were then filled with the formulations under test and examined 30 days postoperatively. Through SEM-EDX scanning, histological assessments, and evaluation of bone metabolic markers, Ru/CC treatment significantly enhanced bone healing, improved bone microarchitecture, increased trabecular bone area, enhanced osteogenic gene expression, and reduced osteoclast activity. Experiments proved that Ru/CC successfully enhances osteogenesis and reduces osteoclastogenesis, proposing it as a promising therapeutic approach for enhancing bone regeneration in osteoporosis.

Carbon Dots as Bioactive Antifungal Nanomaterials.

Nowadays, the widespread diffusion of infections caused by opportunistic fungi represents a demanding threat for global health security. This phenomenon has also worsened by the emergence of contagious events in hospitalisation environments and by the fact that many fungi have developed harsh and serious resistance mechanisms to the traditional antimycotic drugs. Hence, the design of novel antifungal agents is a key factor to counteract mycotic infections and resistance. Within this context, nanomaterials are gaining increasing attention thanks to their biocidal character. Among these, carbon dots (CDs) represent a class of zero-dimensional, photoluminescent and quasi-spherical nanoparticles which, for their great and tuneable features, have found applications in catalysis, sensing and biomedicine. Nevertheless, only a few works define and recapitulate their antifungal properties. Therefore, we aim to give an overview about the recent advances in the synthesis of CDs active against infective fungi. We described the general features of CDs and fungal cells, by highlighting some of the most common antimycotic mechanisms. Then, we evaluated the effects of CDs, antimicrobial drugs-loaded CDs and CDs-incorporated packaging systems on different fungi and analysed the use of CDs as fluorescent nano-trackers for bioimaging, showing, to all effects, their promising application as antifungal agents.

Biobased Polymers Enabling the Synthesis of Ultralong Silver Nanowires and Other Nanostructures.

Conventional polyol synthesis of silver nanowires has exclusively relied on polyvinylpyrrolidone (PVP), a nonbiodegradable polymer with no viable alternatives. The underlying reaction mechanism remains unclear. Herein, we discovered a new sustainable solution by employing biobased cellulose derivatives, including hydroxyethyl cellulose (HEC), as effective substitutes for PVP. Under mild reaction conditions (125 °C, ambient pressure), HEC facilitates the growth of ultralong silver nanowires (>100 μm) from penta-twinned silver seeds through a four-stage kinetic process. Theoretical calculations further reveal that HEC is physiosorbed onto the silver surfaces, while the presence of bromide ions (Br-) facilitates the evolution of seeds into nanowires. By varying halide ion concentrations and substitution in different cellulose derivatives, we successfully synthesized silver nanostructures with additional intriguing morphologies, including quasi-spherical nanoparticles, bipyramids, and nanocubes. Furthermore, transparent conductive films fabricated from ultralong silver nanowires synthesized with HEC demonstrated superior performance compared to those made with PVP-synthesized nanowires.

Rapid Size Determination of Quasispherical Gold Nanoparticles by Electrocatalysis Efficiency-Regulated Electrochemiluminescence.

The size of gold nanoparticles (AuNPs) largely decides their properties and applications, making the rapid screening of AuNP size important. Despite the fact that AuNP-amplified electrochemiluminescence (ECL) is widely used in various ECL sensing applications, the mechanism of ECL enhancement remains elusive, especially the quantitative relationship between the enhanced ECL intensity and the size of AuNPs. In this work, taking quasispherical and citrate-stabilized AuNPs as model nanoparticles, we have reported that the ECL intensity of the S2O82--O2 system enhanced significantly with the increasing AuNP size. AuNPs acted as bielectrocatalysts for reducing the S2O82- and O2. The further study of enhancement mechanism demonstrates that AuNPs with increasing size facilitate the electron transfer and promote the generation of radicals required for the ECL emission, which produces more emitters-singlet oxygen. Meanwhile, the high surface density of citrate on small AuNPs suppresses the ECL signal by forming an electrostatic barrier. On the basis of the above phenomena, an ECL-based rapid AuNP size screening approach has been established. The accuracy of this platform is verified by the consistent results in comparison to transmission electron microscopy (TEM) measurements. This work not only provides deep insight into the correlation between the AuNP size and the ECL enhancement but also contributes an alternative to the TEM technique for the rapid AuNP size screening. Additionally, this study also extends the exploration of ECL-based structure analysis techniques toward nanomaterials through clarifying the structure-electrocatalytic activity correlation.

Effect of colloidal magnetite (Fe3O4) nanoparticles on the electrical characteristics of the azolectin bilayer in a static inhomogeneous magnetic field

This work is devoted to the study of the combined effects of applied magnetic field and MNPs on the electrical characteristics of bilayer lipid membranes. We present results of the study of electrical parameters of azolectin membranes in a static inhomogeneous magnetic field at the one-sided addition of positively charged quasi-spherical superparamagnetic magnetite nanoparticles with a diameter of about 4 nm. The magnet was located at different distances from the membrane, and the magnetic field attracted the nanoparticles to the membrane surface with different strengths. We observed three pronounced effects that depended on the external magnetic field. Firstly, after addition of nanoparticles in a magnetic field, the conductance of the membranes increased. A smooth increase in conductance was accompanied in some cases by the appearance of current jumps, which can be associated with the formation of through pores with a radius of no more than 1 nm. The conductance increased with increasing magnetic field gradient. Secondly, at zero command voltage, a negative current through the membrane was observed. Although our experiments did not allow us to unambiguously determine which particles create this current, we believe that this current is associated with the penetration of particles through the membrane. This effect intensified with increasing magnetic field gradient. Thirdly, we observed a sharp change in the nonlinear dependence of capacitance on voltage associated both with the change in the surface potential of the azolectin membrane and with the effect of MNP binding to the membrane surface on the apparent membrane capacitance.

N,N-dibenzyl dithiocarbamato silver(I) as precursor for silver sulfide nanophotocatalysts for photocatalytic degradation of rhodamine 6G and trypan blue dyes

N,N-dibenzyl dithiocarbamate silver(I) was synthesized and characterized by spectroscopic techniques and single crystal X-ray crystallography. The complex crystallizes in the trigonal space group P31 to form a one-dimensional, chain-like polymeric structure connected by Ag-Ag argentophilic and Ag-S interactions. The complex was used as single source precursor and thermolyzed at 120, 160 and 200 °C in 1-dodecanethiol to prepare silver sulfide nanoparticles (AgS-120, AgS-160 and AgS-200). TEM images showed quasi-spherical nanoparticles with average particle sizes of 4.0, 5.4 and 5.5 nm for nanoparticles prepared at 120, 160 and 200 °C, respectively, with optical band gaps of 3.76, 3.81 and 3.71 eV. The as-prepared silver sulfide nanoparticles potential as photocatalysts were evaluated using rhodamine 6G and trypan blue under irradiation. The photocatalytic degradation efficiency of 42.4% (k = 3.03 × 10−3), 41.9% (k = 2.73 × 10−3) and 56.7% (k = 4.16 × 10−3) for rhodamine 6G dye and 35.4% (2.94 × 10−3), 49.7% (3.87 × 10−3) and 16.9% (9.0 × 10−4) for trypan blue dye were obtained in the presence of AgS-120, AgS-160 and AgS-200, respectively. The kinetics and mechanism of photocatalytic reaction show that the dye degradation in the presence of the as-prepared nanoparticles follow pseudo-first order kinetics.

Biogenic Carbon Quantum Dots: Synthesis and Applications.

The new class of nanomaterials termed carbon dots: a quasi-spherical nanoparticle having a size less than 10 nm, possesses some unique characteristics like good aqueous solubility, colloidal stability, resistance to photobleaching, and fluorescence tunability, resulting in the unfolding of their various properties and their usage in different applications. Materials that are naturally derived or produced by living organisms are termed 'biogenic'. Over the past few years, there has been a gradual increase in the use of naturally derived materials in synthesizing carbon dots. Green precursors or biogenic materials are of low cost, readily available, renewable, and environmentally benign. Most importantly, they provide essential benefits not found in synthesized carbon dots. This review focuses on the use of biogenic materials for the synthesis of biogenic carbon dots developed in the past five years. It also briefly explains different synthetic protocols used, along with some significant findings. Thereafter, an overview of the use of biogenic carbon dots (BCDs) in different applications like chemo and biosensors, drug delivery, bioimaging, catalysis and energy applications, etc., is discussed. Thus biogenic carbon dots are future sustainable materials that are now fast replacing conventional carbon quantum prepared from other sources.

Investigation of column purified dye derived carbon nanomaterials for security printing and supercapacitor applications

Literature evidence reveals versatile applications of carbon dots (CDs), but generally mixtures of various types of carbon nanomaterials, molecular intermediates as well as side products are obtained upon hydrothermal treatment of the precursor material. This demands isolation of pure components and their complete characterization before these nano carbonaceous materials are chosen for suitable applications. In the present study, perylenetetracarboxylic dianhydride (PTCDA) is subjected to hydrothermal treatment and the mother liquor obtained is separated using column chromatography technique using dichloromethane-methanol solvent system to isolate fractions of various fluorescent carbonaceous nanostructures. The TEM imaging of nano carbonaceous particles of all five fractions indicated that the first and third fractions were composed of nanoribbons, while the latter two fractions largely contained quasi-spherical nanoparticles of both lesser (carbon quantum dots) and greater (carbon nanodots) than 10 nm dimensions. The XPS results of all the fractions suggested separation based on polarity difference. The ID/IG ratios obtained from Raman spectra implied the presence of several defects on the CDs. The time resolved fluorescence spectra of third, fourth and fifth fractions revealed mono-exponential decay of fluorophores with excitation independent average lifetime values. The fifth fraction exhibited good biocompatibility and the highest absolute fluorescence quantum yield of 58.47 % among all the isolated samples. As these CDs displayed a remarkable rise in the quantum yield to 88.60 % when dispersed in water, a water-based flexo-ink was formulated. The photostable pale yellow flexo print proofs obtained on UV dull paper exhibited a green fluorescence under 365 nm illumination, whereas a yellow glow when shined with blue light, which can serve as an authentication feature for security documents and currency notes. Moreover, as the third fraction constitutes mainly of carbon nanoribbons (CNRs), an optimized polymer electrolyte was prepared along with sodium alginate (SA), and MgCl2 to understand their potential use in energy storage application. A supercapacitor was fabricated and tested for its electrochemical performance such as cyclic voltammtery (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge (GCD). An enhanced current window was observed in the CV of SA/CNRs compared to pure SA and SA/CNRs/Mg films, which indicated a structural interaction of CNRs with SA. The conductivity of SA/CNRs/Mg was lesser than SA/CNRs in EIS studies due to the presence of Mg ions, while pure SA showed lesser conductivity. The dual ionic interaction of Na and Mg along with enhanced structural stability due to doped CNRs favors its convenient supercapacitor application. The fabricated eco-friendly supercapacitor showed a specific capacitance of 84 F/g. The GCD of the device displayed pseudocapacitance behaviour and was quite stable for 2000 cycles with coulombic efficiency of 96 %.

A review on carbon quantum dot/semiconductor-based nanocomposites as hydrogen production photocatalysts.

Carbon quantum dots (CQDs) are discrete, quasi-spherical carbon nanoparticles with sizes below 10 nm. The properties of CQDs can be further enhanced by doping with elements such as nitrogen, phosphorous, sulphur, and boron or co-doping with heteroatoms such as nitrogen-phosphorous, nitrogen-sulphur, and nitrogen-boron. These excellent properties of CQDs can be utilized to enhance the photocatalytic performance of semiconductors. Therefore, in this review, we summarize different types of bare CQD-scaffolded semiconductors, both doped and co-doped, used for photocatalytic hydrogen production. Moreover, the detailed photocatalytic mechanism of CQD/semiconductor-based hydrogen production is reviewed. Recent progress in the design and development of CQD-based photocatalysts, along with the challenges involved, is comprehensively reviewed.

Antimicrobial Activity of Green Synthesized Silver and Copper Oxide Nanoparticles against the Foodborne Pathogen Campylobacter jejuni.

Campylobacter jejuni is a major cause of global foodborne illnesses. To develop alternative antimicrobial strategies against C. jejuni, this study designed and optimized the green synthesis of metallic nanoparticles (NPs) with intracellular components of the medicinal fungus Ganoderma sessile to provide the needed reducing and stabilizing agents. NPs were characterized by transmission electron microscopy and dynamic light scattering, and the quasi-spherical NPs had sizes of 2.9 ± 0.9 nm for the copper oxide NPs and 14.7 ± 0.6 nm for the silver NPs. Surface charge assessment revealed zeta potentials of -21.0 ± 6.5 mV and -24.4 ± 7.9 mV for the copper oxide and silver NPs, respectively. The growth inhibition of C. jejuni by the NPs occurred through attachment to the outer cell membrane and subsequent intracellular internalization and resulted in minimum inhibitory concentrations of the silver NPs at 6 µg/mL and copper oxide NPs at 10 µg/mL. On the other hand, a differential ROS production caused by silver and copper NPs was observed. In summary, this research presents the first demonstration of using green synthesis with the medicinal fungus G. sessile to produce metallic NPs that effectively inhibit C. jejuni growth, providing a sustainable and effective approach to the traditional use of antimicrobials.

Novel Synthesis and Characterization of Lanthanum oxide Nanoparticles from Nano-sized Lanthanum(III) Compound

A new nano-sized La (III) compound, La[(N2H4)2{C10H6(3-O)(2-COO)}1.5].H2O (X), was synthesized by the sonochemical method and characterized by field emission scanning electron microscope (FESEM), X-ray powder diffraction (XRD) and elemental analyses. Lanthanum oxide nanoparticles were prepared by direct thermal decomposition of nanostructures in a programmable furnace up to 800 ℃ in ambient atmosphere. The structural characterization was done by powder XRD, and morphological observations by FESEM revealed that the quasi-spherical La2O3 nanoparticles obtained are well crystallized and uniform in both morphology and particle size. The study demonstrates that supramolecular compounds may be suitable precursors for the simple one-pot preparation of nanoscale metal oxide materials with different morphologies.

Zinc oxide and copper oxide nanoparticles as a potential solution for controlling Phytophthora infestans, the late blight disease of potatoes

Late blight, caused by Phytophthora infestans, is a major potato disease globally, leading to significant economic losses of $6.7 billion. To address this issue, we evaluated the antifungal activity of ZnO and CuO nanoparticles (NPs) against P. infestans for the first time in laboratory and greenhouse conditions. Nanoparticles were synthesized via a chemical precipitation method and characterized using various techniques. The XRD results revealed that the synthesized ZnO nanoparticles had a pure hexagonal wurtzite crystalline structure, whereas the CuO NPs had a monoclinic crystalline structure. TEM images confirmed the synthesis of quasi-spherical nanoparticles with an average size of 11.5 nm for ZnO NPs and 24.5 nm for CuO NPs. The UV–Vis Spectral Report showed peaks corresponding to ZnO NPs at 364 nm and 252 nm for CuO NPs.In an in vitro study, both ZnO and CuO NPs significantly (p < 0.05) inhibited the radial growth of P. infestans at all tested concentrations compared to the untreated control. The highest inhibitory effect of 100% was observed with ZnO and CuO NPs at 30 mg/L. A lower inhibition of 60.4% was observed with 10 mg/L CuO NPs. Under greenhouse conditions, 100 mg/L ZnO NPs was the most effective treatment for controlling potato late blight, with an efficacy of 71%. CuO NPs at 100 mg/L followed closely, with an efficacy of 69%. Based on these results, ZnO and CuO NPs are recommended as promising eco-friendly fungicides for the management and control of potato late blight after further research.Graphical abstract

Fluorescent carbon dots for discriminating cell types: a review.

Carbon dots (CDs) are quasi-spherical carbon nanoparticles with excellent photoluminescence, good biocompatibility, favorable photostability, and easily modifiable surfaces. CDs, serving as fluorescent probes, have emerged as an ideal tool for cellular differentiation owing to their outstanding luminescence performance and tunable surface properties. In this review, we summarize the recent research progress with CDs in the differentiation of cancer/normal cells, Gram-positive/Gram-negative bacteria, and live/dead cells, as well as the cellular differences used for differentiation. Additionally, we summarize the preparation methods, raw materials, and properties of the CDs used for cell discrimination. The differentiation mechanisms and the advantages or limitations of the differentiation methods are also introduced. Finally, we propose several research challenges in this field and future research directions that require extensive investigation. It is hoped that this review will help researchers in the design of new CDs as ideal fluorescent probes for realizing diverse cell differentiation applications.

Catalytic Degradation Efficacy of Silver Nanoparticles Fabricated Using Actinidia deliciosa Peel Extract

The preparation of metallic nanoparticles using green synthetic approaches and its application toward the efficient degradation of environmentally hazardous dyes constitutes an attractive alternative to currently employed methods. In the current report, the green synthesis of silver nanoparticles (AgNPs) was successfully achieved using Actinidia deliciosa (kiwifruit) peel aqueous extract as a bioreducing agent under optimized synthesis conditions. The experimental parameters were optimized in terms of reactant ratio, reaction temperature, and reaction time. The biogenic nanoparticles exhibited SPR absorption band at λmax 480 nm. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images revealed quasispherical monodisperse nanoparticles which were 36 nm in diameter. The hydrodynamic diameter of the nanoparticles was 106 nm as determined by dynamic light scattering, and the highly negative ζ-potential (−34 mV) supported its superior colloidal stability. Energy dispersive X-ray confirmed that silver is a major constituent of the nanoparticles. X-ray diffraction (XRD) diffractograms confirmed the crystallinity of the nanoparticles and its face-centered cubic (fcc) lattice structure. The functional groups in the plant’s phytochemicals facilitating the reduction of Ag+ ions and stabilization of the formed AgNPs were identified by fourier transform infrared (FTIR) spectroscopy. In specific, the bands in the FTIR spectra at 3,412, 1,618, 1,419, and 1,237 cm−1 suggested the presence of phenolic compounds. Phytochemical analysis by colorimetric assays revealed that the kiwifruit peel extract was rich in phenolic compounds. When evaluated in the catalytic degradation of organic dyes, the biosynthesized AgNPs induced instant and complete discoloration of the methylene blue dye when 1.6 mg of nanoparticles was used. At a lower dose of AgNPs (0.4 mg), 80% degradation of the dye occurred after 3 hr of treatment. The degradation reaction followed second-order kinetics with a rate constant of 0.01083 mM−1s−1. The current study highlights the immense potential of the prepared nanoparticles as efficient catalysts for the degradation of hazardous organic dyes such as methylene blue and presents an intriguing argument for investigating the catalytic efficiency of the biogenic AgNPs for the degradation of other structurally different dye pollutants.

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+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{15+}$$\\end{document} 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\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^6$$\\end{document} with a limit of detection 10-8\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{-8}$$\\end{document} M. Whereas nanoparticles with refined morphology and shapes upon irradiation present high enhancement factors of >107\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^7$$\\end{document} and detection limit down to 10-9\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{-9}$$\\end{document} 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%.

Bactericidal effect of nanosilver synthesized with Neolitsea cassia mucilaginous extract

This study focused on green synthesis of silver nanoparticles using mucilaginous leaf extracts of Neolitsea cassia and demonstrating the bactericidal effect of the product against Staphylococcus aureus and Escherichia coli, which are common in polluted water. A concentration series of silver nitrate was subjected to four treatments by mixing with separate (a) aqueous and (b) 80% methanol extracts of N. cassia leaves in (c) atmospheric and (d) nitrogen gaseous environments, for comparison. A linear increment of the dry weight of silver nanoparticles was observed with increasing silver nitrate concentration (r = 0.99, p = 0), resulting in higher yields from 80% methanol extracts in an atmospheric environment. As characterized by surface plasmon resonance absorption, energy-dispersive X-ray spectroscopy and scanning electron microscopy, quasi-spherical crystalline silver nanoparticles of 11.7 nm average diameter were synthesized. The disk diffusion method showed that the growth of E. coli and S. aureus in culture media was increasingly inhibited with increasing nanoparticle concentration (r = 0.95, p = 0 and r = 0.93, p = 0, respectively). It was concluded that 80% methanol extract in an atmospheric environment was the most productive way to green-synthesize silver nanoparticles from the mucilaginous sap of N. cassia.

Green synthesis of cerium oxide nanoparticles using Portulaca oleracea Extract: Photocatalytic activities

This paper presents a novel method for synthesizing cerium oxide nanoparticles (CeO2 NPs) using Portulaca oleracea extract, focusing on their structural, optical, and photocatalytic properties. CeO2 NPs were prepared through a simple, cost-effective, and environmentally friendly protocol, utilizing the reducing and stabilizing properties of Portulaca oleracea. Structural analysis revealed the formation of cubic CeO2 with an average crystallite size of 16 nm. Optical studies using FTIR and Raman spectroscopy confirmed the characteristic absorption bands of Ce-O and O-Ce-O bonds, while HR-TEM imaging showcased quasi-spherical nanoparticles with sizes ranging from 4 nm to 14 nm. The synthesized CeO2 NPs exhibited significant photocatalytic activity towards the degradation of methylene blue (MB) and methyl orange (MO) under visible light irradiation. The degradation efficiencies achieved were 98 % for MB and 95 % for MO. Kinetic analysis indicated pseudo-first-order degradation kinetics, with observed rate constants of 0.018 min−1 for MO and 0.014 min−1 for MB. Furthermore, CeO2 NPs demonstrated stable and reusable photocatalytic performance over five cycles, highlighting their potential for practical applications in wastewater treatment. Overall, this study presents a promising eco-friendly approach for synthesizing CeO2 NPs with enhanced photocatalytic properties, contributing to the advancement of green nanotechnology for environmental remediation.

One-pot synthesis of near-infrared absorbing silver nanoprisms via a simple photochemical method using an ultraviolet-C light source

This study describes a simple one-pot photochemical method to synthesize triangular silver nanoprisms (T-AgNPs), for which a mixture of silver nitrate (AgNO3) and citrate was irradiated with an ultraviolet-C (UVC) lamp reactor. We successfully synthesized T-AgNPs with edge lengths ranging from 50 to 150 nm, showing a significant localized surface plasmon resonance (LSPR) band over a wavelength of 1200 nm. This photochemical reaction appears to be unrestricted by plasmon resonance conditions, allowing for the formation of colloidal T-AgNPs with an LSPR band in the near-IR region. In addition, this new method does not require any highly reactive reducing agents or initially prepared silver seed solution. The reduction of Ag+ ions by citrate is induced by UVC light, and the nascent Ag first undergoes nucleation to form spherical or quasi-spherical silver nanoparticles (S-AgNPs). Subsequently, continuous irradiation with UVC light facilitates the transformation of these S-AgNPs into T-AgNPs. The growth kinetics of the nanoparticles with different reaction conditions were examined using ultraviolet–visible–near-infrared spectroscopy and transmission electron microscopy. This new method offers a simple, efficient, and cost-effective means to synthesize T-AgNPs with near-IR LSPR, contributing to wider applications in the fields of optoelectronics, spectroscopics, photovoltaics, etc.