Fluorescent light mediated a green synthesis of silver nanoparticles using the protein extract of weaver ant larvae

Nanoparticles-mediated entomotoxicology: lessons from biologica

Nanotechnology has grown in importance in medicine, manufacturing, and consumer products. Nanoparticles (NPs) are also widely used in the field of insect pest management, where they show a variety of toxicological effects on insects. As a result, the primary goal of this review is to compile and evaluate available information on effects of NPs on insects, by use of a timely, bibliometric analysis. We also discussed the manufacturing capacity of NPs from insect tissues and the toxic effects of NPs on insects. To do so, we searched the Web of Science database for literature from 1995 to 2023 and ran bibliometric analyses with CiteSpace© and Bibliometrix©. The analyses covered 614 journals and identified 1763 relevant documents. We found that accumulation of NPs was one of the top trending topics. China, India, and USA had the most published papers. The most overall reported models of insects were those of Aedes aegypti (yellow fever mosquito), Culex quinquefasciatus (southern house mosquito), Bombyx mori (silk moth), and Anopheles stephensi (Asian malaria mosquito). The application and methods of fabrication of NPs using insect tissues, as well as the mechanism of toxicity of NPs on insects, were also reported. A uniform legal framework is required to allow nanotechnology to fully realize its potential while minimizing harm to living organisms and reducing the release of toxic metalloid nanoparticles into the environment.

Progress of Metal Nanomaterial Controllable Preparation by Photoreduction

Metal nanoparticles (NPs) are widely used in biomedicine, catalysis, environment, electronics, and other fields, which is closely related to its structural form. For this purpose, researchers have been looking for a simple, green, and controllable way to mass produce metal nanomaterials with desired characteristics (shape, size, stability, etc.). Due to the surface plasmon resonance (SPR) effect of metal nanoparticles, photoreduction method can control the morphology of metal nanoparticles well, which is also simple, large-scalable, and energy-saving. This review provides an overview of the photoreduction method for the synthesis of metal nanoparticles and discusses the factors such as the light source, pH value, reagents, and temperature on the morphology of the nanoparticles. Finally, the challenges and development trends in the controlled preparation of nanomaterials are proposed.

Role of metal-nanoparticles in farming practices: an insight

Nanotechnology introduces revolutionary approaches for agriculture in the form of nano-based pesticides, fertilizers, sensors, weed-controlling agents, enhanced seed germination materials, etc. Even though metal-nanoparticles (NPs) have shown their potential to improve crop yield, the mode of action at the cellular level and fate in the human body and the environment are not well understood yet. Several metal-nanoparticles have been studied extensively by researchers for their active role in enhancing the rate of seed germination and crop quality augmentation which may happen due to several mechanisms such as increased porosity in nano-primed seeds inducing up-regulation of the expression of aquaporin and Reactive Oxygen Species (ROS) genes involved in water uptake, improving the root dehydrogenase activity to enhance the water absorption capability, etc. However, researchers have also demonstrated and reported the possible toxicity of NPs in the environment due to their agricultural practices. But the fate of NPs and their environmental impact are still unclear and largely vary based on several factors such as the size of NPs, coating material, mode of discharge and locations, etc. This review thoroughly focuses on the mode of action of various NPs in seed germination and accumulation, translocation through cells, and potential environmental and health risks.

Role of a novel cationic gemini surfactant (CGS) on a one-step sol-gel process and photocatalytic properties of TiO2 powders

TiO₂ nanoparticles were prepared using a sol-gel process in combination with a novel cationic gemini surfactant (CGS) with amide functional groups at low temperatures. Titanium (IV) isopropoxide (TIP) and CGS were used as the starting materials and as effective agents, respectively, to orient the nanoparticles during the sol-gel synthesis. To reveal both the structural and morphological properties of the nanopowders prepared in this work, they were characterized using X-ray diffraction (XRD) analysis, scanning electron microscope (SEM), and Brunauer-Emmett-Teller (BET) surface area apparatus. The pore volume and pore size were calculated using the Barrett-Joyner-Halenda (BJH) model on the desorption branch. The experimental results show that the surface area and average crystallite size of the obtained TiO₂ nanopowders vary between 160-203 m²/g and 27-49 nm, respectively. It was observed that the N₂ adsorption-desorption isotherms for almost all samples of TiO₂-X% CGS (X: mass of CGS) show the typical Type I with a hysteresis loop of H4. The photocatalytic activities of the CGS-modified nanocomposites are evaluated not only by the photocatalytic degradation of methyl orange (MO) but also by the reduction of Cr(VI) as model pollutants in the presence of visible light.

Nanoarchitectonics for enhanced antibacterial activity with Lactobacillus buchneri S-layer proteins-coated silver nanoparticles

Various multi-drug-resistant microorganisms have appeared while a single antibacterial agent is increasingly no longer adequate for dealing with these resistant microorganisms. Herein, commercially purchased 50 nm-average-diameter silver nanoparticles (AgNPs) and Lactobacillus buchneri-isolated surface-layer proteins (SLPs) as a capping agent were used to fabricate a hybrid antibacterial agent (SLP-AgNPs) with enhanced antibacterial activity, and the possible synergistic antibacterial mechanism was explored. Characterization results revealed that SLP-AgNPs were uniformly surrounded by protein corona provided from SLP, and the formulations were mainly mediated by the electrostatic interactions and hydrogen bonding, which was evidenced by the results of Fourier transform infrared spectroscopy. According to the antibacterial tests, the minimum inhibitory concentration of SLP-AgNPs against Salmonella enterica (0.010 mg/mL) and Staphylococcus aureus (0.005 mg/mL) was 5-10 times lower than that of bare AgNPs, and while SLP-AgNPs showed a higher antibiofilm activity. Furthermore, bacterial cells exposed to SLP-AgNPs exhibited higher cell membrane permeability and stronger inhibition of respiratory-chain dehydrogenase activity, resulting in more severe cell death compared with bare AgNPs. The synergistic effect of SLP on AgNPs was probably carried out by enhanced function of adhesion to bacteria and antibacterial ability of SLP and SLP's supramolecular lattice structure on the sustained release of silver ion.

Biosynthesis and Cytotoxic Properties of Ag, Au, and Bimetallic Nanoparticles Synthesized Using Lithospermum erythrorhizon Callus Culture Extract

The present study reports a green chemistry approach for the rapid and easy biological synthesis of silver (Ag), gold (Au), and bimetallic Ag/Au nanoparticles using the callus extract of Lithospermum erythrorhizon as a reducing and capping agent. The biosynthesized nanoparticles were characterized with ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD) analysis, and transmission electron microscopy (TEM). Our results showed the formation of crystalline metal nanostructures of both spherical and non-spherical shape. Energy dispersive X-ray (EDX) spectroscopy showed the characteristic peaks in the silver and gold regions, confirming the presence of the corresponding elements in the monometallic particles and both elements in the bimetallic particles. Fourier-transform infrared (FTIR) spectroscopy affirmed the role of polysaccharides and polyphenols of the L. erythrorhizon extract as the major reducing and capping agents for metal ions. In addition, our results showed that the polysaccharide sample and the fraction containing secondary metabolites isolated from L. erythrorhizon were both able to produce large amounts of metallic nanoparticles. The biosynthesized nanoparticles demonstrated cytotoxicity against mouse neuroblastoma and embryonic fibroblast cells, which was considerably higher for Ag nanoparticles and for bimetallic Ag/Au nanoparticles containing a higher molar ratio of silver. However, fibroblast migration was not significantly affected by any of the nanoparticles tested. The obtained results provide a new example of the safe biological production of metallic nanoparticles, but further study is required to uncover the mechanism of their toxicity so that the biomedical potency can be assessed.

Photocatalytic, antiproliferative and antimicrobial properties of copper nanoparticles synthesized using Manilkara zapota leaf extract: A photodynamic approach

Copper nanoparticles were synthesized using Manilkara zapota leaf extract. The synthesis of the nanoparticle was primarily visualized when the colour of the reaction mixture turned into reddish-brown. Biosynthesized nanoparticles were characterized by UV-vis, FT-IR, XRD, SEM and EDX. The UV spectra showed maximum absorption at 584 nm. FT-IR studies showed stretching frequency at 592.76 cm^-1, which is the fingerprint region for Cu-O bond. The crystallinity of the synthesized copper nanoparticles (Mz-Cu NPs) was revealed through XRD analysis. The synthesized Mz-Cu NPs were spherical with an average size of 18.9-42.5 nm and it was shown by SEM analysis. EDX analysis displayed that the nano sample contains 58 % of copper. The antimicrobial property of the synthesized nanoparticles was evaluated against fungal plant pathogens Rhizoctonia solani (MTCC 12232), Sclerotium oryzae (MTCC 12230) and bacterial species, namely Bacillus subtilis (ATCC 23857), Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923), Vibrio harveyi (ATCC 35084), Vibrio parahaemolyticus (ATCC 33845). In in-vitro haemolytic assay, the particle showed 5.73, 3.34, 0.5 % hemolysis at 100, 50, 25 μg/mL concentration respectively. In the antiproliferative assay, the IC₅₀ values of MCF7 and Vero cells were found to be 53.89 and 883.69 μg/μl. The particle degraded Methyl violet, Malachite green and Coomassie brilliant blue by 92.2, 94.9 and 78.8 %, within 50, 40 and 60 min, respectively, through its photocatalytic activity.

Light emitting diode irradiation induced shape conversion of DNA-capped silver nanoparticles and their antioxidant and antibacterial activities

Due to size- and shape-dependent properties, a shape-controlled synthesis of silver nanoparticles (AgNPs) is one of the research challenging topics for their production and potential applications. This work reported the simple eco-friendly syntheses of different shaped AgNPs controlled by the plasmid DNA content and light emitting diodes (LEDs) irradiation. The synthesized AgNPs appeared as yellow, orange and green colloidal AgNPs, which transmission electron microscope (TEM) images revealed their different shapes; spherical AgNPs, a mixture of spherical and hexagonal AgNPs, and a mixture of spherical, hexagonal and corner-truncated triangle AgNPs, respectively. The average sizes of spherical, hexagonal and corner-truncated triangle AgNPs in the green colloidal solution were 12.32 ± 2.22, 23.03 ± 6.62 and 15.84 ± 4.31 nm, respectively. The analyses of X-ray diffraction, selected area electron diffraction and high-resolution TEM indicated the crystalline nature of the synthesized particles as the face-centred cubic silver. All synthesized AgNPs exhibited antioxidant activities similarly, whereas the yellow colloidal AgNPs exhibited the strongest antibacterial activity against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus as compared with the green and orange colloidal AgNPs.

Egg extract of apple snail for eco-friendly synthesis of silver nanoparticles and their antibacterial activity

Green synthesis of silver nanoparticles (AgNPs) provides the alternative method with cost effectiveness and the eco-friendly process by using natural biomolecules as reducing and stabilizing agents. Alternative to the most studies of plant extracts, this work demonstrated a use of egg extract of apple snail (Pomacea canaliculata) for an eco-friendly production of AgNPs. The extract contained at least six proteins with the molecular weight in a range of 24-65 kDa that exhibited the reducing activity. The dispersive AgNPs were produced in the reaction containing only the extract and silver nitrate, as determined by the characteristic surface plasmon resonance peak of silver at 412 nm. The synthesized AgNPs were spherical with the average diameter of 9.0 ± 5.9 nm. The X-ray diffraction pattern and selected area electron diffraction (SAED) analyses confirmed the face-cubic centre (fcc) unit cell structure of AgNPs. The synthesized AgNPs exhibited the antibacterial activity against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. Results of this work clearly showed the potential use of the egg extract of apple snail for a green synthesis of small size AgNPs exhibiting the antibacterial activity.