Green synthesis of silver nanoparticles using Eucalyptus leucoxylon leaves extract and evaluating the antioxidant activities of extract

Evaluation of antimicrobial, anti-inflammatory and cytotoxic effects of silver nanoparticles synthesised from Cynodon dactylon

Plant mediated synthesis of metal nanoparticles (MNPs) has been considered as a reliable green technique for mitigating the involvement of toxic chemicals and which is widely used for desired applications. In the present study, a simple and environment friendly approach for the synthesis of silver nanoparticles (AgNPs) using the aqueous extract of Cynodon dactylon was proposed. The phytochemicals present in C. dactylon acted as the reducing as well as the capping agents during the nanoparticle synthesis. The aqueous extract of C. dactylon added to AgNO3 solution showed a colour change from brown to black at room temperature which confirmed the formation of AgNPs. UV-Vis spectral analysis revealed the surface plasmon resonance band of synthesised AgNPs at around 380 nm, while FT-IR spectroscopy confirmed the role of biomolecules present in the plant extract in the reduction and efficient stabilisation of AgNPs. The X-ray diffraction (XRD) patterns confirmed distinctive peaks corresponding to the crystalline planes of cubic silver. Shape and surface morphology of green AgNPs were examined by SEM. Biosynthesized AgNPs were predominantly cubical and spherical with an average particle size of 30.5 nm approximately as observed through SEM and DLS analysis respectively. The EDS analysis displayed intense signals of silver element. The stability of AgNPs was confirmed by zeta potential analysis. A negative zeta potential value of -17.1 mV indicated the stability and good dispersion of AgNPs. Antimicrobial and anti-inflammatory potentials of green synthesised AgNPs were analysed through in vitro techniques. The cytotoxic effect of green AgNPs on normal fibroblast cells (L929) was studied to analyse its effect on normal cells.

Enhanced antimycotic activity of biomodified copper oxide nanoparticles from indigenous state flowers of Jharkhand: an in vitro and in silico approach

Current study investigates the medicinal applications of Butea monosperma (Palash), the state flower of Jharkhand, India, focusing on synthesising biomodified copper oxide nanoparticles (CuO-NPs) and its antifungal properties. Flavonoid content in the flower extract was quantified by aluminium chloride colorimetric analysis. CuO-NPs were synthesised via co-precipitation method and then modified with methanolic flower extract. Characterization confirmed the properties of these NPs including their high crystallinity, spherical structure and nanoscale size (9-90 nm size). Anti-fungal activity revealed significant inhibition of hyphal growth at concentrations of 100-1000 ppm (76.6% for F. oxysporum and 75.05% for S. rolfsii). Statistical and computational analysis confirmed the effectiveness of these NPs by showing strong interactions between the CuO-NPs and fungal proteins.

QBD approach for green synthesis of Rutin silver nanoparticles- screening for antioxidant, anticancer and anticlastogenic potential

Rutin is a flavonoid glycoside abundant in many plants exhibiting pharmacological activities like antioxidant, anticancer, anti-inflammatory and antimicrobial activities. Plant biomarkers suffer low bioavailability and solubility that lack clinical effectiveness. The smart nanoparticles conversion addresses this limitation with optimal particle size and targeted drug delivery. The present study involves QbD approach for formulation of Rutin silver nanoparticles and evaluation of antioxidant, anticancer and anticlastogenic potential. QbD experimentation involved particle size and drug release as dependent variables over the silver nitrate concentration, methanol and sonication time as independent variables devising 15 formulations (F1 -F15). F12 formulation was found to be optimized with 126.3 nm average size, stable and dispersible characterized by UV, FTIR, SEM and DLS studies. The calibration curve of Rutin was plotted at 352 nm with linearity (LOD = 0.061 μg/ml and LOQ = 0.187 μg/ml). The invitro drug release studies by USP dissolution apparatus I (Basket type) proved the sustained release characteristics with 97.3 % drug release when compared to the Rutin. The pharmacological screening for potential antioxidant and anticancer activity on G361 and MCF 7 cell line of F12 formulation have shown promising results and also enhanced solubility in water compared to Rutin. Anticalstogenic potential as a function of induced micronuclei frequency was evaluated as a characteristic feature in bone marrow cells obtained from mice. Results indicate pre-treatment with the F12 reduced frequency of micronuclei in mouse bone marrow cells caused by Cyclophosphamide (CP) significantly. The protective effect of F12 in suppression was demonstrated at both dosages of 100 and 200 mg/kg. Thus the findings suggest the novel Rutin silver nanoparticles as lead drug serving as antioxidant, anticancer and anticlastogenic agent.

Nanotherapy for Cancer and Biological Activities of Green Synthesized AgNPs Using Aqueous Saussurea costus Leaves and Roots Extracts

Background/Objectives: Nanoparticles derived from medicinal plants are gaining attention for their diverse biological activities and potential therapeutic applications. Methods: This study explored the antioxidant, anti-inflammatory, anti-tumoral, and antimicrobial properties of green synthesized silver nanoparticles (AgNPs) using the aqueous leaf and root extracts of Saussurea costus (S. costus). The physicochemical characterizations of both biosynthesized AgNPs using the aqueous leaf extract (L-AgNPs) and root extract (R-AgNPs) were examined using UV spectroscopy, fluorescence spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, dynamic light scattering, and Fourier-transform infrared spectroscopy. The antioxidant activity measured using ABTS, DPPH, and FRAP assays showed that AgNPs, particularly from roots, had higher activity than aqueous extracts, attributed to phenolic compounds acting as capping and antioxidant agents. Results: Enzyme inhibition studies indicated that AgNPs exhibited remarkable anti-inflammatory effects, inhibiting COX-1, 5-LOX, and secreted PLA2 enzymes by over 99% at 120 µg/mL, comparable to standard drugs. The anti-tumoral effects were evaluated on the human cancer cell lines HCT-116, LoVo, and MDA-MB-231, with AgNPs inhibiting cell proliferation dose-dependently and IC50 values between 42 and 60 µg/mL, demonstrating greater potency than extracts. The AgNPs also showed enhanced antimicrobial activities against various microbial strains, with IC50 values as low as 14 µg/mL, which could be linked to nanoparticle interactions with microbial cell membranes, causing structural damage and cell death. Conclusions: These findings suggest that S. costus-derived AgNPs are promising natural, biodegradable agents for various biological applications and potential new therapeutic agents, necessitating further research to explore their mechanisms and applications.

"Therapeutic advancements in nanomedicine: The multifaceted roles of silver nanoparticles"

Nanotechnology has the advantages of enhanced bioactivity, reduced toxicity, target specificity, and sustained release and NPs can penetrate cell membranes. The small size of silver nanoparticles, AgNPs, large surface area, and unique physicochemical properties contribute to cell lysis and increased permeability of cell membranes used in the field of biomedicine. Functional precursors integrate with phytochemicals to create distinctive therapeutic properties and the stability of the nanoparticles can be enhanced by Surface coatings and encapsulation methods, The current study explores the various synthesis methods and characterization techniques of silver nanoparticles (AgNPs) and highlights their intrinsic activity in therapeutic applications, Anti-cancer activity noted at a concentration range of 5-50 μg/ml and angiogenesis is mitigated at a dosage range of 10-50 μg/ml, Diabetes is controlled within the same concentration. Wound healing is improved at concentrations of 10-50 μg/ml and with a typical range of 10-08 μg/ml for bacteria with antimicrobial capabilities. Advancement of silver nanoparticles with a focus on the future use of AgNPs-coated wound dressings and medical devices to decrease the risk of infection. Chemotherapeutic drugs can be administered by AgNPs, which reduces adverse effects and an improvement in treatment outcomes. AgNPs have been found to improve cell proliferation and differentiation, making them beneficial for tissue engineering and regenerative medicine. Our study highlights emerging patterns and developments in the field of medicine, inferring potential future paths.

Comparative Effect of Chemical and Green Zinc Nanoparticles on the Growth, Hematology, Serum Biochemical, Antioxidant Parameters, and Immunity in Serum and Mucus of Goldfish, Carassius auratus (Linnaeus, 1758)

Recently, nano feed supplement research has great attention to improving healthy aquatic production and improving the aquatic environment. With the aims of the present study, chemical and green synthesized nanoparticles are characterized by various instrumentation analyses, namely UV-Vis spectrophotometry (UV-Vis), X-ray diffraction (XRD), Fourier transform infra-red (FTIR) spectroscopy, and scanning electron microscope (SEM). After characterization analysis of these nanoparticles utilized in aquatic animals, the composition ratio is as follows: controls (without ZnO-NPs (0 mg/L)), T1 (0.9 mg/L ZnO-NPs), T2 (1.9 mg/L ZnO-NPs), T3 (0.9 mg/L GZnO-NPs), T4 (1.9 mg/L GZnO-NPs). SEM investigation report demonstrates that the structure of the surface of green synthesized zinc oxide nanoparticles (GZnO-NPs) was conical shape and the size ranging was from 60 to 70 nm. Concerning hematological parameters, the quantity of hemoglobin increased in different doses of green zinc nanoparticles, but the values of MCV and MCH decreased somewhat. However, this decrease was the highest in the T2 group. Total protein and albumin decreased in T2 and triglyceride, cholesterol, glucose, cortisol, creatinine, and urea increased, while in T3 and T4 groups, changes in biochemical parameters were evaluated as positive. Mucosal and serum immunological parameters in the T2 group showed a significant decrease compared to other groups. In zinc nanoparticles, with increasing dose, oxidative damage is aggravated, so in the T2 group, a decrease in antioxidant enzymes and an increase in MDA were seen compared to other groups. In this regard, the concentration of liver enzymes AST and ALT increased in the T2 group compared with control and other groups. This can confirm liver damage in this dose compared with control and other groups. This research work suggests that green synthesized form of zinc nanoparticles in higher doses have less toxic effects in comparison to the chemical form of zinc nanoparticles and can act as suitable nutrient supplements in aquatic animals.

Metal nanoparticles as a potential technique for the diagnosis and treatment of gastrointestinal cancer: a comprehensive review

Gastrointestinal (GI) cancer is a major health problem worldwide, and current diagnostic and therapeutic approaches are often inadequate. Various metallic nanoparticles (MNPs) have been widely studied for several biomedical applications, including cancer. They may potentially overcome the challenges associated with conventional chemotherapy and significantly impact the overall survival of GI cancer patients. Functionalized MNPs with targeted ligands provide more efficient localization of tumor energy deposition, better solubility and stability, and specific targeting properties. In addition to enhanced therapeutic efficacy, MNPs are also a diagnostic tool for molecular imaging of malignant lesions, enabling non-invasive imaging or detection of tumor-specific or tumor-associated antigens. MNP-based therapeutic systems enable simultaneous stability and solubility of encapsulated drugs and regulate the delivery of therapeutic agents directly to tumor cells, which improves therapeutic efficacy and minimizes drug toxicity and leakage into normal cells. However, metal nanoparticles have been shown to have a cytotoxic effect on cells in vitro. This can be a concern when using metal nanoparticles for cancer treatment, as they may also kill healthy cells in addition to cancer cells. In this review, we provide an overview of the current state of the field, including preparation methods of MNPs, clinical applications, and advances in their use in targeted GI cancer therapy, as well as the advantages and limitations of using metal nanoparticles for the diagnosis and treatment of gastrointestinal cancer such as potential toxicity. We also discuss potential future directions and areas for further research, including the development of novel MNP-based approaches and the optimization of existing approaches.

High-efficiency degradation catalytic performance of a novel Angelica sinensis polysaccharide-silver nanomaterial for dyes by ultrasonic cavitation

Currently, the polluted wastewater discharged by industry accounts for the major part of polluted bodies of water. As one of the industrial wastewaters, dye wastewater is characterized by high toxicity, wide pollution, and difficulty in decolorization degradation. In this paper, a novel composite nanomaterial catalyst of silver was prepared by using Angelica sinensis polysaccharide (ASP) as a reducing and stabilizing agent. And the optimum reaction conditions explored are V_AgNO3 = 5 mL (300 mM) and v_ASP = 7% (w/v) for 6 h at 90 °C. In addition, the ASP-Ag nanocatalyst was characterized by several techniques. The results demonstrated that ASP-Ag nanoparticles were successfully synthesized. Degradation rate, which provides a numerical visualization of the percentage reduction in pollutant concentration. With the wrapping of ASP, the ultrasonic catalytic degradation rates of different organic dyes including rhodamine B (RB), methylene blue (MB), and methyl orange (MO) were from 88.2%, 88.7%, and 85.2% to 96.1%, 95.2% and 93.5% at room temperature, respectively. After the experiments, when c_dyes = 10 mg/L, the highest degradation rate can be observed under c_APS-AgNPs = 10 mg/L with the most powerful cavitation frequency f = 59 kHz. The effect of ultrasonic frequency on the acoustic pressure distribution in the reactor was investigated by using COMSOL Multiphysis^@ software to propose the mechanism of ultrasonic degradation and the mechanism was confirmed by OH radical trapping experiments. It indicates that OH produced by the ultrasonic cavitation effect plays a determinant role in the degradation. And then, the intermediate products of the dye degradation process were analyzed by gas chromatography and mass spectrometry (GC-MS), and the possible degradation processes of dyes were proposed. The resulting products of degradation are SO₄^2-, NH₄⁺, NO₃^-, N₂, CO₂ and H₂O. Finally, the recycling degradation experiments showed that catalyst maintains a high degradation rate within reusing 5 cycles. Thus, this catalyst is highly efficient and recyclable.

Synthesis and characterization of plant extracted silver nanoparticles and advances in dental implant applications

Dental implantology has always emphasized silver nanoparticles (AgNPs) for various applications due to their biocompatibility, antibacterial activity, and increased surface volume ratio offered by these particles. It is utilized to a large extent in the dental implant industry as a surface modification, biocompatible constituent and composite material. AgNPs may be produced inexpensively, sustainably, and environmentally responsibly by utilizing technologies that extract the plant material. The phytochemical components that are contained in plants make them a better, non-toxic, and more cost-effective alternative to both physical and chemical approaches. Because the size and shape of AgNP depend on their synthesis method and technique, and because the efficacy and toxicity of AgNP depend on both size and shape, synthesis methods and techniques have recently become the focus of a significant amount of research attention. In this review, we discussed Plant Extracted Ag-NP's whose sizes range up to 100nm. This review also focuses on recent research advancements in the Plant Extracted synthesis of AgNPs, as well as their characterization methodologies, current obstacles, future possibilities, and applications in dental implantology.

Green synthesis and characterization of silver nanoparticles using Morinda lucida leaf extract and evaluation of its antioxidant and antimicrobial activity

This study emphasizes the production of eco-friendly silver nanoparticles from a medicinal plant extract of Morinda lucida (M. lucida) and investigated its antioxidant and antimicrobial activity. Phytochemical screening of M. lucida (ML) leave extract was carried out and observed to contain some fundamental phyto-reducing agents such as reducing sugar, proteins, and alkaloids. The green synthesized AgNPs (ML-AgNPs) were characterized by UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), transmission emission microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Energy dispersive X-ray analysis (EDX). Thermo gravimetric analysis (TGA) was performed on the synthesized ML-capped AgNPs to determine the thermal stability and the formation of the green synthesized AgNPs. The formation of AgNPs was confirmed by the UV-vis absorption spectra, which showed an absorption band at 420 nm. The morphology of ML extract-mediated AgNPs was mostly spherical and rough-edged crystallite nanostructures, with an average particle size of 11 nm. The FTIR analyses revealed distinctive functional groups which were directly involved in the synthesis and stability of AgNPs. The crystallite size was 8.79 nm, with four intense peaks at 2θ angles of 38°, 44°, 64°, and 77°. At an energy level of 3.4 keV, a significant signal was observed indicating the production of thermally stable and pure crystallite AgNPs. The antioxidant property of green synthesized ML-AgNPs was determined to be 40% higher than that of crude M. lucida leaf extract. The ability of green synthesized ML-AgNPs to scavenge free radicals also increased in the order of OH- < NO < H2O2. The ML-AgNPs have strong activities with a maximum against P. vulgaris and a minimum with E. faecalis.

Size controlled synthesis of silver nanoparticles: a comparison of modified Turkevich and BRUST methods

In the present investigation, silver nanoparticles were synthesized and a comparative analysis was performed of modified Turkevich and BRUST methods. Silver nitrate precursor was reduced by trisodium citrate dihydrate and ascorbic acid was used as a surfactant. Based on Turkevich and BRUST methods, the process variables, i.e., temperature, reducing agent concentration, stirring speed, mode of injecting reducing agent/precursor to large excess volume of either precursor/reducing agent were studied. The size of the particles was preliminarily ascertained by DLS studies and it was found that modified BRUST method yielded silver nanoparticles with average particle size of 25 nm, while modified Turkevich method furnished nanoparticles with average particle size of 15 nm. The silver nanoparticles were characterized by employing the UV/visible, Zeta sizer, scanning electron microscopy (SEM) and energy dispersive microscopy (EDX) techniques. Results revealed that the silver nanoparticles size can be controlled by optimizing the conditions of modified Turkevich and BRUST methods.

Multifarious global flora fabricated phytosynthesis of silver nanoparticles: a green nanoweapon for antiviral approach including SARS-CoV-2

The progressive research into the nanoscale level upgrades the higher end modernized evolution with every field of science, engineering, and technology. Silver nanoparticles and their broader range of application from nanoelectronics to nano-drug delivery systems drive the futuristic direction of nanoengineering and technology in contemporary days. In this review, the green synthesis of silver nanoparticles is the cornerstone of interest over physical and chemical methods owing to its remarkable biocompatibility and idiosyncratic property engineering. The abundant primary and secondary plant metabolites collectively as multifarious phytochemicals which are more peculiar in the composition from root hair to aerial apex through various interspecies and intraspecies, capable of reduction, and capping with the synthesis of silver nanoparticles. Furthermore, the process by which intracellular, extracellular biological macromolecules of the microbiota reduce with the synthesis of silver nanoparticles from the precursor molecule is also discussed. Viruses are one of the predominant infectious agents that gets faster resistance to the antiviral therapies of traditional generations of medicine. We discuss the various stages of virus targeting of cells and viral target through drugs. Antiviral potential of silver nanoparticles against different classes and families of the past and their considerable candidate for up-to-the-minute need of complete addressing of the fulminant and opportunistic global pandemic of this millennium SARS-CoV2, illustrated through recent silver-based formulations under development and approval for countering the pandemic situation.

Graphical abstract

Silver Nanoparticles Using Eucalyptus or Willow Extracts (AgNPs) as Contact Lens Hydrogel Components to Reduce the Risk of Microbial Infection

Eucalyptus leaves (ELE) and willow bark (WBE) extracts were utilized towards the formation of silver nanoparticles (AgNPs(ELE), AgNPs(WBE)). AgNPs(ELE) and AgNPs(WBE) were dispersed in polymer hydrogels to create pHEMA@AgNPs(ELE)_2 and pHEMA@AgNPs(WBE)_2 using hydroxyethyl-methacrylate (HEMA). The materials were characterized in a solid state by X-ray fluorescence (XRF) spectroscopy, X-ray powder diffraction analysis (XRPD), thermogravimetric differential thermal analysis (TG-DTA), differential scanning calorimetry (DTG/DSC) and attenuated total reflection spectroscopy (ATR-FTIR) and ultraviolet visible (UV-vis) spectroscopy in solution. The antimicrobial potential of the materials was investigated against the Gram-negative bacterial strain Pseudomonas aeruginosa (P. aeruginosa) and the Gram-positive bacterial strain of the genus Staphylococcus epidermidis (S. epidermidis) and Staphylococcus aureus (S. aureus), which are involved in microbial keratitis. The percentage of bacterial viability of P. aeruginosa and S. epidermidis upon their incubation over the pHEMA@AgNPs(ELE)_2 discs is interestingly low (28.3 and 6.8% respectively), while the inhibition zones (IZ) formed are 12.3 ± 1.7 and 13.2 ± 1.2 mm, respectively. No in vitro toxicity of this material towards human corneal epithelial cells (HCEC) was detected. Despite its low performance against S. aureus, pHEMA@AgNPs(ELE)_2 could be an efficient candidate towards the development of contact lenses that reduces microbial infection risk.

Toward a Better Understanding of Metal Nanoparticles, a Novel Strategy from Eucalyptus Plants

Nanotechnology is a promising tool that has opened the doors of improvement to the quality of human's lives through its potential in numerous technological aspects. Green chemistry of nanoscale materials (1-100 nm) is as an effective and sustainable strategy to manufacture homogeneous nanoparticles (NPs) with unique properties, thus making the synthesis of green NPs, especially metal nanoparticles (MNPs), the scientist's core theme. Researchers have tested different organisms to manufacture MNPs and the results of experiments confirmed that plants tend to be the ideal candidate amongst all entities and are suitable to synthesize a wide variety of MNPs. Natural and cultivated Eucalyptus forests are among woody plants used for landscape beautification and as forest products. The present review has been written to reflect the efficacious role of Eucalyptus in the synthesis of MNPs. To better understand this, the route of extracting MNPs from plants, in general, and Eucalyptus, in particular, are discussed. Furthermore, the crucial factors influencing the process of MNP synthesis from Eucalyptus as well as their characterization and recent applications are highlighted. Information gathered in this review is useful to build a basis for new prospective research ideas on how to exploit this woody species in the production of MNPs. Nevertheless, there is a necessity to feed the scientific field with further investigations on wider applications of Eucalyptus-derived MNPs.

Silver Nanoparticles from Oregano Leaves' Extracts as Antimicrobial Components for Non-Infected Hydrogel Contact Lenses

The oregano leaves' extract (ORLE) was used for the formation of silver nanoparticles (AgNPs(ORLE)). ORLE and AgNPs(ORLE) (2 mg/mL) were dispersed in polymer hydrogels to give the pHEMA@ORLE_2 and pHEMA@AgNPs(ORLE)_2 using hydroxyethyl-methacrylate (HEMA). The materials were characterized by X-ray fluorescence (XRF) spectroscopy, X-ray powder diffraction analysis (XRPD), thermogravimetric differential thermal analysis (TG-DTA), derivative thermogravimetry/differential scanning calorimetry (DTG/DSC), ultraviolet (UV-Vis), and attenuated total reflection mode (ATR-FTIR) spectroscopies in solid state and UV-Vis in solution. The crystallite size value, analyzed with XRPD, was determined at 20 nm. The antimicrobial activity of the materials was investigated against Gram-negative bacterial strains Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E. coli). The Gram-positive ones of the genus of Staphylococcus epidermidis (S. epidermidis) and Staphylococcus aureus (S. aureus) are known to be involved in microbial keratitis by the means of inhibitory zone (IZ), minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC). The IZs, which developed upon incubation of P. aeruginosa, E. coli, S. epidermidis, and S. aureus with paper discs soaked in 2 mg/mL of AgNPs(ORLE), were 11.7 ± 0.7, 13.5 ± 1.9, 12.7 ± 1.7, and 14.3 ± 1.7 mm. When the same dose of ORLE was administrated, the IZs were 10.2 ± 0.7, 9.2 ± 0.5, 9.0 ± 0.0, and 9.0 ± 0.0 mm. The percent of bacterial viability when they were incubated over the polymeric hydrogel discs of pHEMA@AgNPs(ORLE)_2 was interestingly low (66.5, 88.3, 77.7, and 59.6%, respectively, against of P. aeruginosa, E. coli, S. epidermidis, and S. aureus) and those of pHEMA@ORLE_2 were 89.3, 88.1, 92.8, and 84.6%, respectively. Consequently, pHEMA@AgNPs(ORLE)_2 could be an efficient candidate toward the development of non-infectious contact lenses.

Green synthesis of silver nanoparticles using soluble soybean polysaccharide and their application in antibacterial coatings

In the present work, a facile and green synthesis approach for the production of monodispersed, small-sized (2.9 ± 0.7 nm) and stable silver nanoparticles (AgNPs) using soluble soybean polysaccharide (SSPS) was reported. SSPS was used as the reducing and stabilizing agent. The obtained SSPS-stabilized AgNPs (SA) were characterized by UV-vis absorption spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy and transmission electron microscopy. The antimicrobial activity of the SA colloidal dispersion (SACD) was evaluated based on the growth kinetics of bacteria E. coli and S. aureus. Afterwards, the colloidal dispersion was applied as a coating material to Kraft paper. The SACD-coated Kraft paper exhibited excellent antimicrobial activity against above bacteria strains and P. aeruginosa. The effects of SACD coating on surface wettability, barrier property and microstructure of the Kraft paper were also studied. The results suggested that the SSPS-stabilized AgNPs have great potential in antibacterial applications.

Silver nanoparticles: synthesis, characterisation and biomedical applications

Nanotechnology is a rapidly growing field due to its unique functionality and a wide range of applications. Nanomedicine explores the possibilities of applying the knowledge and tools of nanotechnology for the prevention, treatment, diagnosis and control of disease. In this regard, silver nanoparticles with diameters ranging from 1 to 100 nm are considered most important due to their unique properties, ability to form diverse nanostructures, their extraordinary range of bactericidal and anticancer properties, wound healing and other therapeutic abilities and their cost-effectiveness in production. The current paper reviews various types of physical, chemical and biological methods used in the production of silver nanoparticles. It also describes approaches employing silver nanoparticles as antimicrobial and antibiofilm agents, as antitumour agents, in dentistry and dental implants, as promoters of bone healing, in cardiovascular implants and as promoters of wound healing. The paper also explores the mechanism of action, synthesis methods and morphological characterisation of silver nanoparticles to examine their role in medical treatments and disease management.

Characterization and the evaluation of antimicrobial activities of silver nanoparticles biosynthesized from Carya illinoinensis leaf extract

A green, direct and cost-effective fabrication method is proposed for Eco-environmentally silver nanoparticles (AgNPs) through leaf extraction of Carya illinoinensis from Iran. Formation of Ag NPs was confirmed through different characterization techniques such as UV–Vis Spectroscopy, X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Transmission Electron Microscopy (TEM). UV-Visible spectrophotometer showed absorbance peak at 440 nm due to the Surface Plasmon Resonance (SPR). Based on XRD results and SEM and TEM analysis, AgNPs were crystalline with face-centered cubic geometry and in different sizes ranged 12–30 nm. Furthermore, FTIR Spectroscopy was utilized to recognize the specific functional groups responsible for reducing ion silver to silver nanoparticles and the capping agents available in the leaf extract. In addition, the antibacterial effect of Eco-friendly synthesized nanoparticles and also leaf extract, were evaluated on four pathogens by implementing minimum inhibitory concentration test (MIC) and agar diffusion assay. The MIC results exhibits more inhibiting activity against gram-negative microorganisms (Escherichia coli and Pseudomonas aeruginosa) rather than gram-positive microorganisms (Staphylococcus aureus and Listeria monocytogenes). Compared to leaf extract, nanoparticles have better antimicrobial activity against both Gram-positive and Gram-negative bacteria.

Dissolution of Silver Nanoparticles in Colloidal Consumer Products: Effects of Particle Size and Capping Agent

The utilization of silver nanoparticles (AgNPs) in consumer products has significantly increased in recent years, primarily due to their antimicrobial properties. Increased use of AgNPs has raised ecological concerns. Once released into an aquatic environment, AgNPs may undergo oxidative dissolution leading to the generation of toxic Ag+. Therefore, it is critical to investigate the ecotoxicological potential of AgNPs and determine the physicochemical parameters that control their dissolution in aquatic environments. We have investigated the dissolution trends of aqueous colloidal AgNPs in five products, marketed as dietary supplements and surface sanitizers. The dissolution trends of AgNPs in studied products were compared to the dissolution trends of AgNPs in well-characterized laboratory-synthesized nanomaterials: citrate-coated AgNPs, polyvinylpyrrolidone-coated AgNPs, and branched polyethyleneimine-coated AgNPs. The characterization of the studied AgNPs included: particle size, anion content, metal content, silver speciation, and capping agent identification. There were small differences in the dissolved masses of Ag+ between products, but we did not observe any significant differences in the dissolution trends obtained for deionized water and tap water. The decrease of the dissolved mass of Ag+ in tap water could be due to the reaction between Ag+ and Cl-, forming AgCl and affecting their dissolution. We observed a rapid initial Ag+ release and particle size decrease for all AgNP suspensions due to the desorption of Ag+ from the nanoparticles surfaces. The observed differences in dissolution trends between AgNPs in products and laboratory-synthesized AgNPs could be caused by variances in capping agent, particle size, and total AgNP surface area in suspensions.

Green and Simple Synthesis of Silver Nanoparticles by Aqueous Extract of Perovskia abrotanoides: Characterization, Optimization and Antimicrobial Activity

BACKGROUND

Herein, we report the biosynthesis procedure to prepare silver nanoparticles as reduction and capping agents with the aqueous plant extract of Perovskia abrotanoides.

METHODS

The therapeutic application of silver nanoparticles entirely depends on the size and shape of the nanoparticles therefore, their control during the synthesis procedure is so important. The effects of synthesis factors, for example, silver ion concentration, the mass of plant extract, reaction time and extraction temperature, on the size of silver particles were considered and optimized. Several analytical methods were used for the characterization of silver NPs including FT-IR and UV-Vis spectrophotometer, XRD and SEM.

RESULTS

The results showed that the mean size of the silver particles was about 51 nm. Moreover, the antibacterial properties of biosynthesized silver NPs were investigated by the minimum inhibitory concentration, minimum bactericidal concentration, and Well-diffusion tests. The minimum inhibitory concentration/ minimum bactericidal concentration values of silver NPs and aqueous plant extract versus Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) and Gram-negative bacteria (E. coli) were 3.03/0.00, 1.20/0.01, 3.06/0.00, 0.98/1.04, 1.00/0.05 and 1.30/0.03 (mg/mL), respectively.

CONCLUSION

The antimicrobial activity study displayed that the synthesized silver nanoparticles by plant extract have better antimicrobial properties compared to aqueous plant extract of Perovskia abrotanoides.

Silver nanoparticles as antimicrobial therapeutics: current perspectives and future challenges

Utility of silver metal in antimicrobial therapy is an accepted practice since ages that faded with time because of the identification of a few silver resistant strains in the contemporary era. A successive development of antibiotics soon followed. However, due to an indiscriminate and unregulated use coupled with poor legal control measures and a dearth of expertise in handling the critical episodes, the antibiotics era has already seen a steep decline in the past decades due to the evolution of multi-drug resistant 'superbugs' which pose a sizeable challenge to manage with. Due to limited options in the pipeline and no clear strategy in the forefront, the aspirations for novel, MDR focused drug discovery to target the 'superbugs' arose which once again led to the rise of AgNPs in antimicrobial research. In this review, we have focused on the green routes for the synthesis of AgNPs, the mode of microbial inhibition by AgNPs, synergistic effect of AgNPs with antibiotics and future challenges for the development of nano-silver-based therapeutics.

Phytofabrication of Iron Nanoparticles for Hexavalent Chromium Remediation

Hexavalent chromium is a genotoxic and carcinogenic byproduct of a number of industrial processes, which is discharged into the environment in excessive and toxic concentrations worldwide. In this paper, the synthesis of green iron oxide nanoparticles using extracts of four novel plant species [Pittosporum undulatum, Melia azedarach, Schinus molle, and Syzygium paniculatum (var. australe)] using a "bottom-up approach" has been implemented for hexavalent chromium remediation. Nanoparticle characterizations show that different plant extracts lead to the formation of nanoparticles with different sizes, agglomeration tendencies, and shapes but similar amorphous nature and elemental makeup. Hexavalent chromium removal is linked with the particle size and monodispersity. Nanoparticles with sizes between 5 and 15 nm from M. azedarach and P. undulatum showed enhanced chromium removal capacities (84.1-96.2%, respectively) when compared to the agglomerated particles of S. molle and S. paniculatum with sizes between 30 and 100 nm (43.7-58.7%, respectively) in over 9 h. This study has shown that the reduction of iron salts with plant extracts is unlikely to generate vast quantities of stable zero valent iron nanoparticles but rather favor the formation of iron oxide nanoparticles. In addition, plant extracts with higher antioxidant concentrations may not produce nanoparticles with morphologies optimal for pollutant remediation.

Silver Nanoparticles and Polyphenol Inclusion Compounds Composites for Phytophthora cinnamomi Mycelial Growth Inhibition

Phytophthora cinnamomi, responsible for "root rot" or "dieback" plant disease, causes a significant amount of economic and environmental impact. In this work, the fungicide action of nanocomposites based on silver nanoparticles and polyphenol inclusion compounds, which feature enhanced bioavailability and water solubility, was assayed for the control of this soil-borne water mold. Inclusion compounds were prepared by an aqueous two-phase system separation method through extraction, either in an hydroalcoholic solution with chitosan oligomers (COS) or in a choline chloride:urea:glycerol deep eutectic solvent (DES). The new inclusion compounds were synthesized from stevioside and various polyphenols (gallic acid, silymarin, ferulic acid and curcumin), in a [6:1] ratio in the COS medium and in a [3:1] ratio in the DES medium, respectively. Their in vitro response against Phytophthora cinnamomi isolate MYC43 (at concentrations of 125, 250 and 500 µg·mL^-1) was tested, which found a significant mycelial growth inhibition, particularly high for the composites prepared using DES. Therefore, these nanocomposites hold promise as an alternative to fosetyl-Al and metalaxyl conventional systemic fungicides.

Biosynthesis of silver nanoparticles formation from Caesalpinia pulcherrima stem metabolites and their broad spectrum biological activities

The present work illustrates eco-friendly, rapid and cost effective method of AgNPs synthesis using C. pulcherrima stem extract. Initially, various physico chemical factors were optimized. Characterization was done by different spectroscopic and microscopic analysis. AgNPs were spherical in shape with an average size of 8 nm. AgNPs showed good synergistic antimicrobial, antibiofilm and antioxidant activity. The cytotoxicity effect against HeLa cancer cell line was dose dependent while genotoxic study revealed the non toxic nature of AgNPs at lower concentration. The results suggest that AgNPs from C. pulcherrima stem extract have great potential in biomedical applications.

A systematic review on silver nanoparticles-induced cytotoxicity: Physicochemical properties and perspectives

With the development of nanotechnology, silver nanoparticles (Ag-NPs) have become one of the most in-demand nanoparticles owing to their exponential number of uses in various sectors. The increased use of Ag-NPs-enhanced products may result in an increased level of toxicity affecting both the environment and living organisms. Several studies have used different model cell lines to exhibit the cytotoxicity of Ag-NPs, and their underlying molecular mechanisms. This review aimed to elucidate different properties of Ag-NPs that are responsible for the induction of cellular toxicity along with the critical mechanism of action and subsequent defense mechanisms observed in vitro. Our results show that the properties of Ag-NPs largely vary based on the diversified synthesis processes. The physiochemical properties of Ag-NPs (e.g., size, shape, concentration, agglomeration, or aggregation interaction with a biological system) can cause impairment of mitochondrial function prior to their penetration and accumulation in the mitochondrial membrane. Thus, Ag-NPs exhibit properties that play a central role in their use as biocides along with their applicability in environmental cleaning. We herein report a current review of the synthesis, applicability, and toxicity of Ag-NPs in relation to their detailed characteristics.

Antioxidant, antibacterial and anticancer properties of phytosynthesised Artemisia quttensis Podlech extract mediated AgNPs

The focus of this study is on a rapid and cost-effective approach for the synthesis of silver nanoparticles (AgNPs) using Artemisia quttensis Podlech aerial parts extract and assessment of their antioxidant, antibacterial and anticancer activities. The prepared AgNPs were determined by ultraviolet-visible spectroscopy, X-ray diffraction, Fourier transform infra-red spectroscopy, transmission electron microscopy, scanning electron microscopy, energy-dispersive spectroscopy, and dynamic light scattering and zeta-potential analysis. The AgNPs and A. quttensis extract were evaluated for their antiradical scavenging activity by 2, 2-diphenyl, 1-picryl hydrazyl assay and anticancer activity against colon cancer (human colorectal adenocarcinoma cell line 29) compared with normal human embryonic kidney (HEK293) cells. Also, the prepared AgNPs were studied for its antibacterial activity. The AgNPs revealed a higher antioxidant activity compared with A. quttensis extract alone. The phyto-synthesised AgNPs and A. quttensis extract showed a dose-response cytotoxicity effect against HT29 and HEK293 cells. As evidenced by Annexin V/propidium iodide staining, the number of apoptotic HT29 cells was significantly enhanced, following treatment with AgNPs as compared with untreated cells. Besides, the antibacterial property of the AgNPs indicated a significant effect against the selected pathogenic bacteria. These present obtained results show the potential applications of phyto-synthesised AgNPs using A. quttensis aerial parts extract.

A review on green synthesis of silver nanoparticles and their applications

Development of reliable and eco-accommodating methods for the synthesis of nanoparticles is a vital step in the field of nanotechnology. Silver nanoparticles are important because of their exceptional chemical, physical, and biological properties, and hence applications. In the last decade, numerous efforts were made to develop green methods of synthesis to avoid the hazardous byproducts. This review describes the methods of green synthesis for Ag-NPs and their numerous applications. It also describes the comparison of efficient synthesis methods via green routes over physical and chemical methods, which provide strong evidence for the selection of suitable method for the synthesis of Ag-NPs.

Novel imatinib-loaded silver nanoparticles for enhanced apoptosis of human breast cancer MCF-7 cells

In the current study, in vitro biological feature of imatinib-loaded silver nanoparticles (IMAB-AgNPs) on human breast cancer cell line was investigated. The formation of synthesized silver nanoparticles (AgNPs) was characterized by UV-Visible spectroscopy, EDS, TEM imaging, SEM, FTIR, DLS and Zeta potentiometer. The developed IMAB-AgNPs with maximum percentage of loading efficiency was demonstrated in the average of 130 nm and mostly spherical. Additionally, in vitro drug release study showed a slow and continuous release of imatinib over a period of 80 h. We demonstrated that the synthesized IMAB-AgNPs exhibited a dose-dependent cytotoxicity against MCF-7 cell line. Then, real-time PCR method was also applied for the investigation of Bax and Bcl-2 gene expression in the cells. Comparing IMAB-AgNPs to AgNPs and Imatinib revealed the ability of IMAB-AgNPs to up-regulating Bax/Bcl-2 ratio. An induction of apoptosis was evidenced by Annexin-V/PI detection assay. Based on the current obtained data, the IMAB-AgNPs can exhibit inhibitory effect on viability through up regulation of apoptosis in MCF-7 cancer cells, which provides influencing evidence for the green synthesized AgNPs as a promising sustained drug delivery system.

Phytosynthesis of silver nanoparticles using Artemisia marschalliana Sprengel aerial part extract and assessment of their antioxidant, anticancer, and antibacterial properties

A rapid phytosynthesis of silver nanoparticles (AgNPs) using an extract from the aerial parts of Artemisia marschalliana Sprengel was investigated in this study. The synthesized AgNPs using A. marschalliana extract was analyzed by UV-visible spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy and further characterized by transmission electron microscopy, scanning electron microscopy, zeta potential, and energy-dispersive spectroscopy. Characteristic absorption bands of AgNPs were found near 430 nm in the UV-vis spectrum. Energy-dispersive spectroscopy analysis of AgNPs in the energy range 2-4 keV confirmed the silver signal due to surface plasmon resonance. Scanning electron microscopy and transmission electron microscopy results revealed that the AgNPs were mostly spherical with an average size ranging from 5 nm to 50 nm. The zeta potential value of -31 mV confirmed the stability of the AgNPs. AgNPs produced using the aqueous A. marschalliana extract might serve as a potent in vitro antioxidant, as revealed by 2,2-diphenyl-1-picryl hydrazyl assay. The present study demonstrates the anticancer properties of phytosynthesized AgNPs against human gastric carcinoma AGS cells. AgNPs exerted a dose-dependent inhibitory effect on the viability of cells. Real-time polymerase chain reaction was used for the investigation of Bax and Bcl-2 gene expression in cancer and normal cell lines. Our findings show that the mRNA levels of pro-apoptotic Bax gene expression were significantly upregulated, while the expression of anti-apoptotic Bcl-2 was declined in cells treated with AgNPs compared to normal cells. In addition, flow cytometric analysis showed that the number of early and late apoptotic AGS cells was significantly enhanced following treatment with AgNPs as compared to untreated cells. In addition, the AgNPs showed strong antibacterial properties against tested pathogenic bacteria such as Staphylococcus aureus, Bacillus cereus, Acinetobacter baumannii, and Pseudomonas aeruginosa. Based on the obtained data, we suggest that phytosynthesized AgNPs are good alternatives in the treatment of diseases because of the presence of bioactive agents.

In vitro antioxidant, antimicrobial, cytotoxic potential of gold and silver nanoparticles prepared using Embelia ribes

In recent years, the green synthesis of gold (GNPs) and silver (SNPs) nanoparticles has gained great interest among chemists and researchers. The present study reports an eco-friendly, cost-effective, rapid and easy method for the synthesis of gold and silver nanoparticles using the seed extract of Embelia ribes (SEEr) as capping and reducing agent. The synthesised GNPs and SNPs were characterised using the following techniques: UV-vis spectroscopy, DLS, HR-TEM, FT-IR and XRD. The free radical scavenging potential of GNPs and SNPs was measured by DPPH assay and Phosphomolybdenum assay. Further, the antimicrobial activity against two micro-organisms were tested using disc diffusion method and cytotoxicity of GNPs and SNPs was determined against MCF-7 cell lines at different concentrations by MTT assay. Both the GNPs and SNPs prepared from E. ribes comparatively showed promising results thereby proving their clinical importance.

The chemiluminescence determination of 2-chloroethyl ethyl sulfide using luminol-AgNO3-silver nanoparticles system

A highly sensitive chemiluminescence (CL) method for the determination of 2-chloroethyl ethyl sulfide (2-CEES) was presented. It was found that 2-chloroethyl ethyl sulfide (2-CEES) could inhibit the CL of the luminol-AgNO3 system in the presence of silver nanoparticles in alkaline solution, which made it applicable for determination of 2-CEES. The presented method is simple, convenient, rapid and sensitive. Under the optimized conditions, the calibration curve was linear in the range of 0.0001-1ngmL(-1), with the correlation coefficient of 0.992; while the limit of detection (LOD), based on signal-to-noise ratio (S/N) of 3, was 6×10(-6)ngmL(-1). Also, the relative standard deviation (RSD, n=5) for determination of 2-CEES (0.50ngmL(-1)) was 3.1%. The method was successfully applied for the determination of 2-CEES in environmental aqueous samples.