Green Synthesis of Chromium Oxide Nanoparticles for Antibacterial,Antioxidant Anticancer,and Biocompatibility Activities

This study deals with the green synthesis of chromium oxide (Cr₂O₃) nanoparticles using a leaf extract of Abutilon indicum (L.) Sweet as a reducing and capping agent. Different characterization techniques were used to characterize the synthesized nanoparticles such as X-ray diffraction (XRD), Scanning electron microscope (SEM), Transmission electron microscope (TEM), Energy-dispersive X-ray (EDX), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible (UV-VIS) spectroscopy. The X-ray diffraction technique confirmed the purity and crystallinity of the Cr₂O₃ nanoparticles. The average size of the nanoparticles ranged from 17 to 42 nm. The antibacterial activity of the green synthesized nanoparticles was evaluated against four different bacterial strains, E. coli, S. aureus, B. bronchiseptica, and B. subtilis using agar well diffusion and a live/dead staining assay. The anticancer activities were determined against Michigan Cancer Foundation-7 (MCF-7) cancer cells using MTT and a live/dead staining assay. Antioxidant activity was investigated in the linoleic acid system. Moreover, the cytobiocompatibility was analyzed against the Vero cell lines using MTT and a live/dead staining assay. The results demonstrated that the green synthesized Cr₂O₃ nanoparticles exhibited superior antibacterial activity in terms of zones of inhibition (ZOIs) against Gram-positive and Gram-negative bacteria compared to plant extracts and chemically synthesized Cr₂O₃ nanoparticles (commercial), but comparable to the standard drug (Leflox). The green synthesized Cr₂O₃ nanoparticles exhibited significant anticancer and antioxidant activities against MCF-7 cancerous cells and the linoleic acid system, respectively, compared to chemically synthesized Cr₂O₃ nanoparticles. Moreover, cytobiocompatibility analysis displayed that they presented excellent biocompatibility with Vero cell lines than that of chemically synthesized Cr₂O₃ nanoparticles. These results suggest that the green synthesized Cr₂O₃ nanoparticles’ enhanced biological activities might be attributed to a synergetic effect. Hence, green synthesized Cr₂O₃ nanoparticles could prove to be promising candidates for future biomedical applications.     

Conifer-Derived Metallic Nanoparticles: Green Synthesis and Biological Applications

The use of metallic nanoparticles in engineering and biomedicine disciplines has gained considerable attention. Scientists are exploring new synthesis protocols of these substances considering their small size and lucrative antimicrobial potential. Among the most economical techniques of synthesis of metallic nanoparticles via chemical routes, which includes the use of chemicals as metal reducing agents, is considered to generate nanoparticles possessing toxicity and biological risk. This limitation of chemically synthesized nanoparticles has engendered the exploration for the ecofriendly synthesis process. Biological or green synthesis approaches have emerged as an effective solution to address the limitations of conventionally synthesized nanoparticles. Nanoparticles synthesized via biological entities obtained from plant extracts exhibit superior effect in comparison to chemical methods. Recently, conifer extracts have been found to be effective in synthesizing metallic nanoparticles through a highly regulated process. The current review highlights the importance of conifers and its extracts in synthesis of metallic nanoparticles. It also discusses the different applications of the conifer extract mediated metallic nanoparticles.     

Bionanofactories for Green Synthesis of Silver Nanoparticles: Toward Antimicrobial Applications

Among the various types of nanoparticles and their strategy for synthesis, the green synthesis of silver nanoparticles has gained much attention in the biomedical, cellular imaging, cosmetics, drug delivery, food, and agrochemical industries due to their unique physicochemical and biological properties. The green synthesis strategies incorporate the use of plant extracts, living organisms, or biomolecules as bioreducing and biocapping agents, also known as bionanofactories for the synthesis of nanoparticles. The use of green chemistry is ecofriendly, biocompatible, nontoxic, and cost-effective. We shed light on the recent advances in green synthesis and physicochemical properties of green silver nanoparticles by considering the outcomes from recent studies applying SEM, TEM, AFM, UV/Vis spectrophotometry, FTIR, and XRD techniques. Furthermore, we cover the antibacterial, antifungal, and antiparasitic activities of silver nanoparticles.     

Fruit Extract Mediated Green Synthesis of Metallic Nanoparticles: A New Avenue in Pomology Applications

Fruit extracts have natural bioactive molecules that are known to possess significant therapeutic potential. Traditionally, metallic nanoparticles were synthesized via chemical methods, in which the chemical act as the reducing agent. Later, these traditional metallic nanoparticles emerged as the biological risk, which prompted researchers to explore an eco-friendly approach. There are different eco-friendly methods employed for synthesizing these metallic nanoparticles via the usage of microbes and plants, primarily via fruit extract. These explorations have paved the way for using fruit extracts for developing nanoparticles, as they eliminate the usage of reducing and stabilizing agents. Metallic nanoparticles have gained significant attention, and are used for diverse biological applications. The present review discusses the potential activities of phytochemicals, and it intends to summarize the different metallic nanoparticles synthesized using fruit extracts and their associated pharmacological activities like anti-cancerous, antimicrobial, antioxidant and catalytic efficiency.     

Synthesis of Silver Nanoparticles Using Syzygium malaccense Fruit Extract and Evaluation of Their Catalytic Activity and Antibacterial Properties

Journal of Inorganic and Organometallic Polymers and Materials - In this study, green synthesis of silver nanoparticles, an aqueous Syzygium malaccense fruit extract, was employed...     

Rational Design of Ag/ZnO Hybrid Nanoparticles on Sericin/Agarose Composite Film for Enhanced Antimicrobial Applications

Silver-based hybrid nanomaterials are receiving increasing attention as potential alternatives for traditional antimicrobial agents. Here, we proposed a simple and eco-friendly strategy to efficiently assemble zinc oxide nanoparticles (ZnO) and silver nanoparticles (AgNPs) on sericin-agarose composite film to impart superior antimicrobial activity. Based on a layer-by-layer self-assembly strategy, AgNPs and ZnO were immobilized on sericin-agarose films using the adhesion property of polydopamine. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray powder diffraction spectroscopy were used to show the morphology of AgNPs and ZnO on the surface of the composite film and analyze the composition and structure of AgNPs and ZnO, respectively. Water contact angle, swelling ratio, and mechanical property were determined to characterize the hydrophilicity, water absorption ability, and mechanical properties of the composite films. In addition, the antibacterial activity of the composite film was evaluated against Gram-positive and Gram-negative bacteria. The results showed that the composite film not only has desirable hydrophilicity, high water absorption ability, and favorable mechanical properties but also exhibits excellent antimicrobial activity against both Gram-positive and Gram-negative bacteria. It has shown great potential as a novel antimicrobial biomaterial for wound dressing, artificial skin, and tissue engineering.     

Ecofriendly Synthesis of Silver Nanoparticles by Terrabacter humi sp. nov. and Their Antibacterial Application against Antibiotic-Resistant Pathogens

It is essential to develop and discover alternative eco-friendly antibacterial agents due to the emergence of multi-drug-resistant microorganisms. In this study, we isolated and characterized a novel bacterium named Terrabacter humi MAHUQ-38^T, utilized for the eco-friendly synthesis of silver nanoparticles (AgNPs) and the synthesized AgNPs were used to control multi-drug-resistant microorganisms. The novel strain was Gram stain positive, strictly aerobic, milky white colored, rod shaped and non-motile. The optimal growth temperature, pH and NaCl concentration were 30 °C, 6.5 and 0%, respectively. Based on 16S rRNA gene sequence, strain MAHUQ-38^T belongs to the genus Terrabacter and is most closely related to several Terrabacter type strains (98.2%–98.8%). Terrabacter humi MAHUQ-38^T had a genome of 5,156,829 bp long (19 contigs) with 4555 protein-coding genes, 48 tRNA and 5 rRNA genes. The culture supernatant of strain MAHUQ-38^T was used for the eco-friendly and facile synthesis of AgNPs. The transmission electron microscopy (TEM) image showed the spherical shape of AgNPs with a size of 6 to 24 nm, and the Fourier transform infrared (FTIR) analysis revealed the functional groups responsible for the synthesis of AgNPs. The synthesized AgNPs exhibited strong anti-bacterial activity against multi-drug-resistant pathogens, Escherichia coli and Pseudomonas aeruginosa. Minimal inhibitory/bactericidal concentrations against E. coli and P. aeruginosa were 6.25/50 and 12.5/50 μg/mL, respectively. The AgNPs altered the cell morphology and damaged the cell membrane of pathogens. This study encourages the use of Terrabacter humi for the ecofriendly synthesis of AgNPs to control multi-drug-resistant microorganisms.     

Progress in Laser Ablation and Biological Synthesis Processes: “Top-Down” and “Bottom-Up” Approaches for the Green Synthesis of Au/Ag Nanoparticles

Because of their small size and large specific surface area, nanoparticles (NPs) have special properties that are different from bulk materials. In particular, Au/Ag NPs have been intensively studied for a long time, especially for biomedical applications. Thereafter, they played a significant role in the fields of biology, medical testing, optical imaging, energy and catalysis, MRI contrast agents, tumor diagnosis and treatment, environmental protection, and so on. When synthesizing Au/Ag NPs, the laser ablation and biosynthesis methods are very promising green processes. Therefore, this review focuses on the progress in the laser ablation and biological synthesis processes for Au/Ag NP generation, especially in their fabrication fundamentals and potential applications. First, the fundamentals of the laser ablation method are critically reviewed, including the laser ablation mechanism for Au/Ag NPs and the controlling of their size and shape during fabrication using laser ablation. Second, the fundamentals of the biological method are comprehensively discussed, involving the synthesis principle and the process of controlling the size and shape and preparing Au/Ag NPs using biological methods. Third, the applications in biology, tumor diagnosis and treatment, and other fields are reviewed to demonstrate the potential value of Au/Ag NPs. Finally, a discussion surrounding three aspects (similarity, individuality, and complementarity) of the two green synthesis processes is presented, and the necessary outlook, including the current limitations and challenges, is suggested, which provides a reference for the low-cost and sustainable production of Au/Ag NPs in the future.     

Green Synthesis of Endolichenic Fungi Functionalized Silver Nanoparticles: The Role in Antimicrobial,Anti-Cancer,and Mosquitocidal Activities

Green nanotechnology is currently a very crucial and indispensable technology for handling diverse problems regarding the living planet. The concoction of reactive oxygen species (ROS) and biologically synthesized silver nanoparticles (AgNPs) has opened new insights in cancer therapy. The current investigation caters to the concept of the involvement of a novel eco-friendly avenue to produce AgNPs employing the wild endolichenic fungus Talaromyces funiculosus. The synthesized Talaromyces funiculosus–AgNPs were evaluated with the aid of UV visible spectroscopy, dynamic light scattering (DLS), Fourier infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The synthesized Talaromyces funiculosus–AgNPs (TF-AgNPs) exhibited hemo-compatibility as evidenced by a hemolytic assay. Further, they were evaluated for their efficacy against foodborne pathogens Staphylococcus aureus, Streptococcus faecalis, Listeria innocua, and Micrococcus luteus and nosocomial Pseudomonas aeruginosa, Escherichia coli, Vibrio cholerae, and Bacillus subtilis bacterial strains. The synthesized TF-AgNPs displayed cytotoxicity in a dose-dependent manner against MDA-MB-231 breast carcinoma cells and eventually condensed the chromatin material observed through the Hoechst 33342 stain. Subsequent analysis using flow cytometry and fluorescence microscopy provided the inference of a possible role of intracellular ROS (OH⁻, O⁻, H₂O₂, and O₂⁻) radicals in the destruction of mitochondria, DNA machinery, the nucleus, and overall damage of the cellular machinery of breast cancerous cells. The combined effect of predation by the cyclopoid copepod Mesocyclops aspericornis and TF-AgNPS for the larval management of dengue vectors were provided. A promising larval control was evident after the conjunction of both predatory organisms and bio-fabricated nanoparticles. Thus, this study provides a novel, cost-effective, extracellular approach of TF-AgNPs production with hemo-compatible, antioxidant, and antimicrobial efficacy against both human and foodborne pathogens with cytotoxicity (dose dependent) towards MDA-MB-231 breast carcinoma.     

Green Biogenic Synthesis of Silver Nanoparticles Using Aqueous Extract of Moringa Oleifera: Access to a Powerful Antimicrobial,Anticancer, Pesticidal and Catalytic Agents

In this study, we look into the biogenic synthesis of (AgNPs) utilizing a simple and environmentally friendly method based on an aqueous extract of Moringa Oleifera (MO). The synthesized MOAgNPs were characterized using a UV–Visible spectrophotometry, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra and TEM image which confirmed the spherical shape of MOAgNPs with particle size range of 5–50 nm with an average particle size of 38.7 nm. Significantly, the prepared MOAgNPs showed high pesticidal activity towards Spodoptera littoralis. MOAgNPs also exhibited strong antibacterial activities against Gram-positive and Gram-negative bacteria. The prepared MOAgNPs were screened for their cytotoxic effect against (HCT-116), (HepG-2) and (MCF-7) carcinoma cell lines. Finally, the synthesized MOAgNPs have been used as a catalyst for the reduction of 2,4-Dinitrophenol using NaBH₄ to 2,4-Diaminophenol. Taken together, the outstanding catalytic and biological activities of the synthesized MOAgNPs entitled them for applications as catalyst, pesticidal, antibacterial and anticancer agents in medical applications.

     

Synthesis,Spectroscopy, Single-Crystal Structure Analysis and Antibacterial Activity of Two Novel Complexes of Silver(I) with Miconazole Drug

In a previous article, we reported on the higher toxicity of silver(I) complexes of miconazole [Ag(MCZ)₂NO₃ (1)] and [Ag(MCZ)₂ClO₄ (2)] in HepG2 tumor cells compared to the corresponding salts of silver, miconazole and cisplatin. Here, we present the synthesis of two silver(I) complexes of miconazole containing two new counter ions in the form of Ag(MCZ)₂X (MCZ = 1-[2-(2,4-dichlorobenzyloxy)-2-(2,4-dichlorophenyl)ethyl]-1H-imidazole]; X = BF₄⁻ (3), SbF₆⁻ (4)). The novel silver(I) complexes were characterized by elemental analysis, ¹H NMR, ¹³C NMR and infrared (IR) spectroscopy, electrospray ionization (ESI)-MS spectrometry and X-ray-crystallography. In the present study, the antimicrobial activity of all obtained silver(I) complexes of miconazole against six strains of Gram-positive bacteria, five strains of Gram-negative bacteria and yeasts was evaluated. The results were compared with those of a silver sulfadiazine drug, the corresponding silver salts and the free ligand. Silver(I) complexes exhibited significant activity against Gram-positive bacteria, which was much better than that of silver sulfadiazine and silver salts. The highest antimicrobial activity was observed for the complex containing the nitrate counter ion. All Ag(I) complexes of miconazole resulted in much better inhibition of yeast growth than silver sulfadiazine, silver salts and miconazole. Moreover, the synthesized silver(I) complexes showed good or moderate activity against Gram-negative bacteria compared to the free ligand.     

<Emphasis Type="Italic">Brassica rapa</Emphasis> var. <Emphasis Type="Italic">japonica</Emphasis> Leaf Extract Mediated Green Synthesis of Crystalline Silver Nanoparticles and Evaluation of Their Stability,Cytotoxicity and Antibacterial Activity

Silver nanoparticles (AgNPs) were successfully synthesized from the reduction of Ag⁺ using AgNO₃ solution as a precursor and Brassica rapa var. japonica leaf extract as a reducing and capping agent. This study was aimed at synthesis of AgNPs, exhibiting less toxicity with high antibacterial activity. The characterization of AgNPs was carried out using UV–Vis spectrometry, energy dispersive X-ray spectrometry, fourier transform infrared spectrometry, field emission scanning electron microscopy, X-ray diffraction, atomic absorption spectrometry, and transmission electron microscopy analyses. The analyses data revealed the successful synthesis of nano-crystalline Ag possessing more stability than commercial AgNPs. The cytotoxicity of Brassica AgNPs was compared with commercial AgNPs using in vitro PC12 cell model. Commercial AgNPs reduced cell viability to 23% (control 97%) and increased lactate dehydrogenase activity at a concentration of 3 ppm, whereas, Brassica AgNPs did not show any effects on both of the cytotoxicity parameters up to a concentration level of 10 ppm in PC12 cells. Moreover, Brassica AgNPs exhibited antibacterial activity in terms of zone of inhibition against E. coli (11.1?±?0.5 mm) and Enterobacter sp. (15?±?0.5 mm) which was higher than some previously reported green-synthesised AgNPs. Thus, this finding can be a matter of interest for the production and safe use of green-AgNPs in consumer products.     

Green Synthesis of Silver Nanoparticles through Reduction with Solanum xanthocarpum L. Berry Extract: Characterization, Antimicrobial and Urease Inhibitory Activities against Helicobacter pylori

A green synthesis route for the production of silver nanoparticles using methanol extract from Solanum xanthocarpum berry (SXE) is reported in the present investigation. Silver nanoparticles (AgNps), having a surface plasmon resonance (SPR) band centered at 406 nm, were synthesized by reacting SXE (as capping as well as reducing agent) with AgNO(3) during a 25 min process at 45 °C. The synthesized AgNps were characterized using UV-Visible spectrophotometry, powdered X-ray diffraction, and transmission electron microscopy (TEM). The results showed that the time of reaction, temperature and volume ratio of SXE to AgNO(3) could accelerate the reduction rate of Ag(+) and affect the AgNps size and shape. The nanoparticles were found to be about 10 nm in size, mono-dispersed in nature, and spherical in shape. In vitro anti-Helicobacter pylori activity of synthesized AgNps was tested against 34 clinical isolates and two reference strains of Helicobacter pylori by the agar dilution method and compared with AgNO(3) and four standard drugs, namely amoxicillin (AMX), clarithromycin (CLA), metronidazole (MNZ) and tetracycline (TET), being used in anti-H. pylori therapy. Typical AgNps sample (S1) effectively inhibited the growth of H. pylori, indicating a stronger anti-H. pylori activity than that of AgNO(3) or MNZ, being almost equally potent to TET and less potent than AMX and CLA. AgNps under study were found to be equally efficient against the antibiotic-resistant and antibiotic-susceptible strains of H. pylori. Besides, in the H. pylori urease inhibitory assay, S1 also exhibited a significant inhibition. Lineweaver-Burk plots revealed that the mechanism of inhibition was noncompetitive.     

Green Synthesis of M0 Nanoparticles (M=Pd,Pt, and Ru) for Electrocatalytic Hydrogen Evolution

In recent years the demand for green synthesis and green energy has increased immensely. Herein M⁰ nanoparticles were synthesized using a metal precursor and NaHCO₃ under hydrothermal conditions without using any reducing agent. The nanoparticles were characterized using powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDX). Surprisingly, it found that the Pt and Pd nanoparticles contain a high concentration of carbon. The presence of carbon is also evident from the attenuated transmission resonance infra-red (ATRIR) spectroscopy. Moreover, acetic acid was detected as a byproduct of the hydrothermal reaction. NaHCO₃ can be considered as the dissolution of CO₂ in a mildly alkaline solution. Thus, during the reaction, CO₂ was converted to carbonaceous material, which can be considered as a fixation of CO₂. The synthesized nanoparticles are also efficient catalysts for the electrocatalytic hydrogen evolution reaction (HER). It was found that Ru nanoparticles exhibit the highest activity among the three catalysts studied.