Eco-friendly synthesis of silver and gold nanoparticles with enhanced antimicrobial, antioxidant, and catalytic activities

Promising applications of phyto-fabricated silver nanoparticles: Recent trends in biomedicine

The prospective contribution of phyto-nanotechnology to the synthesis of silver nanomaterials for biomedical purposes is attracting increasing interest across the world. Green synthesis of silver nanoparticles (Ag-NPs) through plants has been extensively examined recently, and it is now seen to be a green and efficient path for future exploitation and development of practical nano-factories. Fabrication of Ag-NPs is the process involves use of plant extracts/phyto-compounds (e.g.alkaloids, terpenoids, flavonoids, and phenolic compounds) to synthesise nanoparticles in more economical and feasible. Several findings concluded that in the field of medicine, Ag-NPs play a major role in pharmacotherapy (infection and cancer). Indeed, they exhibits novel properties but the reason is unclear (except some theoretical interpretation e.g. size, shape and morphology). But recent technological advancements help to address these questions by predicting the unique properties (composition and origin) by characterizing physical, chemical and biological properties. Due to increased list of publications and their application in the field of agriculture, industries and pharmaceuticals, issues relating to toxicity are unavoidable and question of debate. The present reviews aim to find out the role of plant extracts to synthesise Ag-NPs. It provides an overview of various phytocompounds and their role in the field of biomedicine (antibacterial, antioxidant, anticancer, anti-inflammatory etc.). In addition, this review also especially focused on various applications such as role in infection, oxidative stress, application in medical engineering, diagnosis and therapy, medical devices, orthopedics, wound healing and dressings. Additionally, the toxic effects of Ag-NPs in cell culture, tissue of different model organism, type of toxic reactions and regulation implemented to reduce associated risk are discussed critically. Addressing all above explanations, this review focus on the detailed properties of plant mediated Ag-NPs, its impact on biology, medicine and their commercial properties as well as toxicity.

Green Synthesis of Chitosan-Capped Gold Nanoparticles Using Salvia officinalis Extract: Biochemical Characterization and Antimicrobial and Cytotoxic Activities

Increasing antimicrobial resistance to the action of existing antibiotics has prompted researchers to identify new natural molecules with antimicrobial potential. In this study, a green system was developed for biosynthesizing gold nanoparticles (BAuNPs) using sage (Salvia officinalis L.) leaf extract bioconjugated with non-toxic, eco-friendly, and biodegradable chitosan, forming chitosan/gold bioconjugates (Chi/BAuNPs). Characterization of the BAuNPs and Chi/BAuNPs conjugates takes place using transmission electron microscopy (TEM), X-ray spectra, Fourier transform infrared (FT-IR) spectroscopy, and zeta potential (Z-potential). The chemical composition of S. officinalis extract was evaluated via gas chromatography/mass spectrometry (GC/MS). This study evaluated the antioxidant and antimicrobial activities of human pathogenic multidrug-resistant (MDR) and multisensitive (MS) bacterial isolates using the agar diffusion method. Chi/BAuNPs showed inhibition of the MDR strains more effectively than BAuNPs alone as compared with a positive standard antibiotic. The cytotoxicity assay revealed that the human breast adenocarcinoma cancer cells (MCF7) were more sensitive toward the toxicity of 5-Fu + BAuNPs and 5-Fu + Chi/BAuNPs composites compared to non-malignant human fibroblast cells (HFs). The study shows that BAuNPs and Chi/BAuNPs, combined with 5-FU NPs, can effectively treat cancer at concentrations where the free chemical drug (5-Fu) is ineffective, with a noted reduction in the required dosage for noticeable antitumor action.

Catalytic and antioxidant activity of silver nanoparticles fabricated by Neolamarckia cadamba bark extract

Plant parts have unfathomable potential in the synthesis of nanoparticles. The current study was designed for the photosynthesis of silver nanoparticles (NC-AgNPs) using bark extract of N. cadamba. Different analytical methods were used to characterize the synthesized nanoparticles. HR-TEM analysis identifies the formation of multi-shaped NC-AgNPs like spherical, quasi-spherical, rod-shaped, trigonal, square, pentagonal, and hexagonal with a size range of 18-91 nm. The crystallize size of NC-AgNPs was found to be 27.6 nm. The catalytic effectiveness of NC-AgNPs in degrading Crystal violet (CV) dye is remarkable. Important parameters such as the effect of catalyst dose and pH were investigated. Dose-dependentantioxidant activity of NC-AgNPs was determined by using 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay. Low-cost synthesis and eco-friendly reagents were the salient features that made NC-AgNPs more attractive toward catalytic and antioxidant activities.

Plaster Gel Loaded with Silver Nanoparticle-Mediated Ganoderma applanatum: from Fabrication to Evaluation

Traditional Asian remedies have mainly employed the macrofungus Ganoderma applanatum, which belongs to the family Ganodermataceae, as a medicinal mushroom due to its high antibacterial and antioxidant activity. Extracts of the fungus can be synthesized into nanoparticles, which are subsequently produced as plaster gels. Synthesized silver nanoparticle-mediated G. applanatum was discovered to have the greatest ability to inhibit bacterial growth in S. epidermidis. When applied to the skin, the prepared plaster gel converted from a gel to a film; thus, both gel and film generation are characteristic of its formulation. The plaster gel that was made was found to be consistent and attractive, and the yellow color had darkened. Its viscosity and pH were appropriate for the application and allowed it to remain on the skin without dripping or reacting with the skin until it dried. A shorter duration for film formation is possible. The film's tensile was slightly reduced, and it exhibited excellent thermal stability. Decomposition of the generated film occurred at a slower rate, which constrained the polymer chain's ability to move. The semi-crystalline structure was characteristic of the film. It was found that particles were distributed in the film. Rapid release from plaster gel within 4 h was seen, and this was followed by a period of a slowly declining release rate over 12 h. The accurate first-order kinetic used to estimate the release rate of the formulation. The plaster gel demonstrated greater antibacterial activity than the MIC value indicated. The in vivo evaluation was positive and showed no skin irritation. The formulation showed good stability. Therefore, this indicated that the prepared plaster gel is appropriate for topical pharmaceutical delivery and safe for skin application.

Effect of Ionic Liquid on Silver-Nanoparticle-Complexed Ganoderma applanatum and Its Topical Film Formulation

Imidazolium-based ionic liquids have been widely utilized as versatile solvents for metal nanoparticle preparation. Silver nanoparticles and Ganoderma applanatum have displayed potent antimicrobial activities. This work aimed to study the effect of 1-butyl-3-methylimidazolium bromide-based ionic liquid on the silver-nanoparticle-complexed G. applanatum and its topical film. The ratio and conditions for preparation were optimized by the design of the experiments. The optimal ratio was silver nanoparticles: G. applanatum extract: ionic liquid at 97:1:2, and the conditions were 80 °C for 1 h. The prediction was corrected with a low percentage error. The optimized formula was loaded into a topical film made of polyvinyl alcohol and Eudragit^®, and its properties were evaluated. The topical film was uniform, smooth, and compact and had other desired characteristics. The topical film was able to control the release of silver-nanoparticle-complexed G. applanatum from the matrix layer. Higuchi's model was used to fit the kinetic of the release. The skin permeability of the silver-nanoparticle-complexed G. applanatum was improved by about 1.7 times by the ionic liquid, which might increase solubility. The produced film is suitable for topical applications and may be utilized in the development of potential future therapeutic agents for the treatment of diseases.

Arbutin Stabilized Silver Nanoparticles: Synthesis, Characterization, and Its Catalytic Activity against Different Organic Dyes

In this study, we report one-pot, single step synthesis of silver nanoparticles stabilized by using arbutin. The concentration of reducing agent (NaBH4) used in the preparation was kept at double, and arbutin was used as a stabilizing agent. The confirmation of prepared silver nanoparticles was done by color change and UV-Vis surface plasmon resonance peak at 435 nm in UV-Vis spectrum. Size dispersion of nanoparticles was carried out by Dynamic Light Scattering (DLS) and surface charge on nanoparticles. Stability was analyzed by Zeta potential. A strong negative charge indicated that nanoparticles are well stabilized throughout the solution. Morphology and 3D topographic images were obtained by Atomic Force Microscopy (AFM). The crystalline nature of nanoparticles was elucidated by X-ray diffraction analysis. The size and morphology of solid, well-grinded nanoparticles was proceeded by Scanning Electron Microscopy (SEM). The catalytic activities of nanoparticles were carried out against methylene blue, methyl orange, safranin, and eosin. The results demonstrated that synthesized silver nanoparticles commenced the degradation reaction of dyes mentioned. Prepared silver nanoparticles are found to have adequate catalytic activity, as it can be comprehended in time-dependent UV-Vis spectrums of dyes after treating them with AgNPs.

Biosynthesis of silver nanoparticles with antibacterial, antioxidant, anti-inflammatory properties and their burn wound healing efficacy

The current study aims to develop a novel burn wound ointment consisting of sheep’s tail ointment loaded with AgNP. The AgNP in the ointment serves as an antibacterial, antioxidant and anti-inflammatory agent. The AgNP was developed via the biological method with the assistance of the medicinal plant Rhodiola rosea. The characterization of AgNP was assessed using UV-Vis spectroscopy, FTIR, Zeta Potential, XRD, PCCS, SEM, and EDX techniques. The formation of AgNP was confirmed by UV-Vis spectrum at the absorbance of ∼430 nm, and the biomolecules responsible for reducing and capping the AgNP were characterized by FTIR analysis. The stability of AgNP was determined with Zeta potential, which revealed a highly stable colloidal solution with a surface charge of −68.38 ± 3.4 mV. The synthesized AgNP had a face-centered cubic structure with a crystallite size of 23 nm and average grain size of 67.5 nm. The SEM image showed a fairly monodisperse 20 nm-sized spherical-shaped AgNP. The synthesized AgNP contained high purity of the silver, and a low concentration of AgNP inhibited both Gram-positive and Gram-negative bacteria. Moreover, the scavenging activity of AgNP was investigated using DPPH and H₂O₂ scavenging assay, and the results revealed a dose-dependent antioxidant activity with the highest activity at a concentration of 450 μg/ml. Finally, the burn wound healing effect was evaluated by applying the AgNP-loaded ointment to the wound site of BALB/c mice. The in-vivo studies confirmed that AgNP-loaded ointment reduced the wound size, decreased the epidermis layer, and lowered mast cell migration compared to untreated burn wounds. And the synthesized AgNP regulated both pro-inflammatory and anti-inflammatory gene expression, thereby promoting burn wound closure on BALB/c mice. The developed AgNP-loaded ointment has the potential to be applied in the biomedical field.

Evaluating Antimicrobial Activity and Wound Healing Effect of Rod-Shaped Nanoparticles

Presently, the nanotechnology approach has gained a great concern in the media of drug delivery. Gold nanoparticles (Au-NPs) specially having a non-spherical structure, such as gold nanorods (GNR), are attracting much interest as antibacterial agent and many other medical fields. The aim of the current investigation was to characterize Au-NPs and investigate their antimicrobial and wound healing efficacy in diabetic animals. Material and methods: Au-NPs were characterized using a UV-Vis spectrophotometer, estimating their particle size, polydispersity (PDI), and assessing their morphological characters. Further, Au-NPs were estimated for their antibacterial and antifungal behavior. Ultimately, in vivo activity of Au-NPs was evaluated against excision wound healing in STZ-induced diabetic animals. Results: Au-NPs were found to show maximum absorption at 520 nm. They exhibited a particle size of 82.57 nm with a PDI value of 0.323. Additionally, they exhibited good antimicrobial activity against different bacterial strains. Topical application of Au-NPs caused a significantly increased percentage of wound area reduction, lesser time needed for epithelialization, and augmented hydroxyproline, collagen, and hexosamine levels demonstrating enhanced healing processes. Furthermore, Au-NPs displayed a significant intensification in angiogenesis-related factors (HIF-1α, TGF-β1, and VEGF), and antioxidant enzymes activities (CAT, SOD, GPx) as well as mitigated inflammatory mediators IL-6, IL-1β, TNF-α, and NF-κB) and lipid peroxidation (MDA). Conclusion: Au-NPs exhibited proper particle size, and rod-shaped particles, with efficient antimicrobial behavior against different bacterial strains. Furthermore, Au-NPs demonstrated a promising wound healing activity in STZ-induced diabetic animals.

Recent advances on botanical biosynthesis of nanoparticles for catalytic, water treatment and agricultural applications: A review

Green synthesis of nanoparticles using plant extracts minimizes the usage of toxic chemicals or energy. Here, we concentrate on the green synthesis of nanoparticles using natural compounds from plant extracts and their applications in catalysis, water treatment and agriculture. Polyphenols, flavonoid, rutin, quercetin, myricetin, kaempferol, coumarin, and gallic acid in the plant extracts engage in the reduction and stabilization of green nanoparticles. Ten types of nanoparticles involving Ag, Au, Cu, Pt, CuO, ZnO, MgO, TiO₂, Fe₃O₄, and ZrO₂ with emphasis on their formation mechanism are illuminated. We find that green nanoparticles serve as excellent, and recyclable catalysts for reduction of nitrophenols and synthesis of organic compounds with high yields of 83-100% and at least 5 recycles. Many emerging pollutants such as synthetic dyes, antibiotics, heavy metal and oils are effectively mitigated (90-100%) using green nanoparticles. In agriculture, green nanoparticles efficiently immobilize toxic compounds in soil. They are also sufficient nanopesticides to kill harmful larvae, and nanoinsecticides against dangerous vectors of pathogens. As potential nanofertilizers and nanoagrochemicals, green nanoparticles will open a revolution in green agriculture for sustainable development.

A Critical Review of the Antimicrobial and Antibiofilm Activities of Green-Synthesized Plant-Based Metallic Nanoparticles

Metallic nanoparticles (MNPs) produced by green synthesis using plant extracts have attracted huge interest in the scientific community due to their excellent antibacterial, antifungal and antibiofilm activities. To evaluate these pharmacological properties, several methods or protocols have been successfully developed and implemented. Although these protocols were mostly inspired by the guidelines from national and international regulatory bodies, they suffer from a glaring absence of standardization of the experimental conditions. This situation leads to a lack of reproducibility and comparability of data from different study settings. To minimize these problems, guidelines for the antimicrobial and antibiofilm evaluation of MNPs should be developed by specialists in the field. Being aware of the immensity of the workload and the efforts required to achieve this, we set out to undertake a meticulous literature review of different experimental protocols and laboratory conditions used for the antimicrobial and antibiofilm evaluation of MNPs that could be used as a basis for future guidelines. This review also brings together all the discrepancies resulting from the different experimental designs and emphasizes their impact on the biological activities as well as their interpretation. Finally, the paper proposes a general overview that requires extensive experimental investigations to set the stage for the future development of effective antimicrobial MNPs using green synthesis.

Gold Nanoparticle Drug Delivery System: Principle and Application

In recent years, gold nanoparticles (GNPs) have gradually become a major choice of drug delivery cargoes due to unique properties. Compared to traditional bulk solid gold, GNPs have basic physical and chemical advantages, such as a larger surface area-to-volume ratio and easier surface modification. Furthermore, these have excellent biocompatibility, can induce the directional adsorption and enrichment of biological macromolecules, help retain biological macromolecule activity, and cause low harm to the human body. All these make GNPs good drug delivery cargoes. The present study introduces the properties of GNPs, including factors that affect the properties and synthesis. Then, focus was given on the application in drug delivery, not only on the molecular mechanism, but also on the clinical application. Furthermore, the properties and applications of peptide GNPs were also introduced. Finally, the challenges and prospects of GNPs for drug delivery were summarized.

Metallic Structures: Effective Agents to Fight Pathogenic Microorganisms

The current worldwide pandemic caused by coronavirus disease 2019 (COVID-19) had alerted the population to the risk that small microorganisms can create for humankind’s wellbeing and survival. All of us have been affected, directly or indirectly, by this situation, and scientists all over the world have been trying to find solutions to fight this virus by killing it or by stop/decrease its spread rate. Numerous kinds of microorganisms have been occasionally created panic in world history, and several solutions have been proposed to stop their spread. Among the most studied antimicrobial solutions, are metals (of different kinds and applied in different formats). In this regard, this review aims to present a recent and comprehensive demonstration of the state-of-the-art in the use of metals, as well as their mechanisms, to fight different pathogens, such as viruses, bacteria, and fungi.

Formation, antimicrobial activity, and biomedical performance of plant-based nanoparticles: a review

Because many engineered nanoparticles are toxic, there is a need for methods to fabricate safe nanoparticles such as plant-based nanoparticles. Indeed, plant extracts contain flavonoids, amino acids, proteins, polysaccharides, enzymes, polyphenols, steroids, and reducing sugars that facilitate the reduction, formation, and stabilization of nanoparticles. Moreover, synthesizing nanoparticles from plant extracts is fast, safe, and cost-effective because it does not consume much energy, and non-toxic derivatives are generated. These nanoparticles have diverse and unique properties of interest for applications in many fields. Here, we review the synthesis of metal/metal oxide nanoparticles with plant extracts. These nanoparticles display antibacterial, antifungal, anticancer, and antioxidant properties. Plant-based nanoparticles are also useful for medical diagnosis and drug delivery.

Preparation of stimuli responsive microgel with silver nanoparticles for biosensing and catalytic reduction of water pollutants

Poly(N-isopropylacrylamide/2-acrylamido-2-methylpropane sulfonic acid) microgel was prepared and fabricated with silver nanoparticles to design a material for dual functions of catalyst and sensor.

Au Nanoclusters Ameliorate Shigella Infectious Colitis by Inducing Oxidative Stress

Background

Shigella infection has always been a global burden, and it particularly threatens children between the ages of 1 and 5 years. Economically underdeveloped countries are dominated by Shigella flexneri infection. The most effective method to treat Shigella is antibiotics, but with the abuse of antibiotics and the prevalence of multidrug resistance, we urgently need a relatively safe non-antibiotic treatment to replace it. Ultrasmall Au nanoclusters (NCs) have special physical and chemical properties and can better interact with and be internalized by bacteria to disrupt the metabolic balance. The purpose of this study was to explore whether Au NCs may be a substitute for antibiotics to treat Shigella infections.

Methods

Au NCs and Shigella Sf301, R2448, and RII-1 were cocultured in vitro to evaluate the bactericidal ability of Au NCs. The degree of damage and mode of action of Au NCs in Shigella were clearly observed in images of scanning electron microscopy (SEM). In vivo experiments were conducted to observe the changes in body weight, clinical disease activity index (DAI) and colon (including length and histopathological sections) of mice treated with Au NCs. The effect of Au NCs was analysed by measuring the content of lipocalin-2 (LCN2) and Shigella in faeces. Next, the changes in Shigella biofilm activity, the release of reactive oxygen species (ROS), the changes in metabolism-related and membrane-related genes, and the effect of Au NCs on the body weight of mice were determined to further analyse the mechanism of action and effect.

Results

Au NCs (100 μM) interfered with oxidative metabolism genes, induced a substantial increase in ROS levels, interacted with the cell membrane to destroy it, significantly killed Shigella, and effectively alleviated the intestinal damage caused by Shigella in mice. The activity of the biofilm formed by Shigella was reduced.

Conclusion

The effective antibacterial effect and good safety suggest that Au NCs represent a good potential alternative to antibiotics to treat Shigella infections.

Biomineralized separation, concentration, and evaluation of the effectiveness of Schisandra chinensis fruit extract

Here, we detail the biomineralization-assisted separation and concentration of crude food extract and an evaluation of its effectiveness. Schisandra chinensis fruit extract was used as a model plant extract. Hybrid grape-like mineral was assembled by calcium carbonate mineralization. The hybrid particles of S. chinensis mineral were fully characterized using field emission scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, and particle size analysis. Data including the Brunauer-Emmett-Teller surface area, single point total pore volume, and adsorption/desorption analysis of pore size were also investigated. Organic molecules, including lipids such as palmitic acid, stearic acid, and linolenic acid in the Schisandra chinensis fruit, affect the formation of complex structures involving the CaCO₃ mineralization pathway by inhibiting crystallization. However, the cosmetic active primary components were entrapped in a similar proportion in the preserved extract, and were efficiently separated without additional filtering and concentration steps for purification. In addition, the hybrid mineral was enriched (10.5 times) in Gomisin N, a representative component of S. chinensis fruit, relative to its concentration in the initial extract samples. The hybrid mineral inhibited both intracellular and extracellular melanin production and increased the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity. The data provide the first evidence of the potential use of fruit extract for obtaining hybrid minerals and the effectiveness of the biomineralization-based separation and concentration strategy.

Cyclodextrin-mediated gold nanoparticles as multisensing probe for the selective detection of hydroxychloroquine drug

β-Cyclodextrin (β-CD) modified gold nanoparticles (AuNP) were rapidly synthesized using microwave assisted procedure. Parameters, such as time, pH and concentrations of β-CD and gold, were optimized for the synthesis of β-CD-AuNP. The addition of enantiomers and racemic mixture of hydroxychloroquine (R-HCQ, S-HCQ and RS-HCQ) drugs and their interaction with β-CD led to a red shift in the surface plasmon resonance of β-CD-AuNP. The changes associated with the introduction of HCQ in β-CD-AuNP were studied using various characterization techniques such as UV-vis, FT-IR, XRD, dynamic light scattering, zeta potential, transmission electron microscopy, fluorescence spectroscopy and electrochemical techniques. The host-guest interaction of β-cyclodextrin with S-HCQ, R-HCQ and RS-HCQ resulted in the aggregation of gold nanoparticles. The surface plasmon resonance at 521 nm for β-CD-AuNP was shifted to 600, 620 and 670 nm on the addition of S-HCQ, R-HCQ and RS-HCQ, respectively, with a color change from pink to blue. The selectivity and sensitivity of the developed system for RS-HCQ were investigated and the limit of detection (LOD=3 s/m) was found to be 2.61, 0.15, and 0.85 nM for optical, fluorescence and electrochemical methods, respectively. The successful monitoring of RS-HCQ drug in pharmaceutical samples is possible with these techniques.

Electronic Supplementary Material

Supplementary material is available for this article at 10.1007/s11814-020-0719-7 and is accessible for authorized users.

Green-synthesized nanocatalysts and nanomaterials for water treatment: Current challenges and future perspectives

Numerous hazardous environmental pollutants in water bodies, both organic and inorganic, have become a critical global issue. As greener and bio-synthesized versions of nanoparticles exhibit significant promise for wastewater treatment, this review discusses trends and future prospects exploiting the sustainable applications of green-synthesized nanocatalysts and nanomaterials for the removal of contaminants and metal ions from aqueous solutions. Recent trends and challenges about these nanocatalysts and nanomaterials and their potential applications in wastewater treatment and water purification are highlighted including toxicity and biosafety issues. This review delineates the pros and cons and critical issues pertaining to the deployment of these nanomaterials endowed with their superior surface area, mechanical properties, significant chemical reactivity, and cost-effectiveness with low energy consumption, for removal of hazardous materials and contaminants from water; comprehensive coverage of these materials for industrial wastewater remediation, and their recovery is underscored by recent advancements in nanofabrication, encompassing intelligent and smart nanomaterials.

Mild temperature photothermal assisted anti-bacterial and anti-inflammatory nanosystem for synergistic treatment of post-cataract surgery endophthalmitis

Rationale: Endophthalmitis, which is one of the severest complications of cataract surgeries, can seriously threaten vision and even lead to irreversible blindness owing to its complicated microenvironment, including both local bacterial infection and severe inflammation. It is urgent to develop a comprehensive treatment for both anti-bacterial and anti-inflammatory effects.

Methods: Herein, we developed AuAgCu₂O-bromfenac sodium nanoparticles (AuAgCu₂O-BS NPs), which was designed to combine anti-bacterial and anti-inflammatory effects for integrated therapy of endophthalmitis after cataract surgery. The AuAgCu₂O-BS NPs could eradicate methicillin-resistant Staphylococcus aureus (MRSA) bacterial strain relied on their photodynamic effects and the release of metal ions (Ag⁺ and Cu⁺) by the hollow AuAgCu₂O nanostructures mediated mild photothermal effects. The anti-inflammatory drug, bromfenac sodium, released from the nanoparticles were able to significantly reduce the local inflammation of the endophthalmitis and promote tissue rehabilitation. In vivo bacterial elimination and anti-inflammation were confirmed by a postcataract endophthalmitis rabbit model.

Results: Excellent antibacterial ability of AuAgCu₂O-BS NPs was verified both in vitro and in vivo. Ophthalmological clinical observation and pathologic histology analysis showed prominent treatment of inflammatory reaction. Importantly, the mild temperature photothermal effect not only promoted the release of metal ions and bromfenac sodium but also avoided the thermal damage of the surrounding tissues, which was more suitable for the practical application of ophthalmology due to the complex structure of the eyeball. Moreover, superior biocompatibility was approved by the preliminary toxicity investigations, including low cytotoxicity, negligible damage to major organs, and stable intraocular pressure.

Conclusions: Our studies of nanosystem provide a promising synergic therapeutic strategy for postcataract endophthalmitis treatment with favorable prognosis and promise in clinical translations.

Utilizing waste corn-cob in biosynthesis of noble metallic nanoparticles for antibacterial effect and catalytic degradation of contaminants

In the present study, cost-effective, and environmentally friendly fabrication of silver and gold nanoparticles was performed by using aqueous extract of waste corn-cob. The formation of the metallic nanoparticles (MNPs) was optimized by UV-Vis method. The phytoconstituents were responsible for reduction of silver and gold ions to silver nanoparticles (CC-AgNPs) and gold nanoparticles (CC-AuNPs) which were demonstrated by Fourier-transform infrared (FTIR) spectroscopy while formation of AgCl was attributed to the presence of chloride ions in the aqueous extract. The crystalline nature of the AgNPs, AgCl, and AuNPs was confirmed using the X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns. Morphological studies showed that the synthesized CC-AgNPs existed in spherical shape with the size ranging from 2 to 28 nm possessing an average value of 11 nm while CC-AuNPs were present in the multiple shapes with size ranging from 5 to 50 nm possessing an average value of 35 nm. For studies on bioactive application, the CC-AgNPs exhibited a high antibacterial activity against three bacterial strains including Salmonella typhimurium, Bacillus cereus, and Staphylococcus aureus. In addition, the catalytic efficiency of MNPs was investigated for reduction of o-, m-, p-nitrophenols, and degradation of organic dyes including Eosin Y and Rhodamine 6G. The rate constants calculated from the kinetical data revealed that the biosynthesized nanoparticles are excellent catalysts in potential applications for treatment of wastewater. Graphical abstract .

Free Radical Scavenging and Some Pharmaceutical Utilities of Nanoparticles in the Recent Scenario

BACKGROUND

Nanopharmaceuticals have rapidly emerged as a means to cure several diseases. There are numerous reports describing the development and application of nanopharmaceuticals. Here, we discussed nanoparticle synthesis and the mechanisms to scavenge free radicals. We also discuss their major properties and list several commercially available nanomedicines.

RESULTS

Reactive oxygen and hydrogen species are formed during normal metabolism, and excessive reactive species can damage proteins, lipids, and DNA and cause disease. Plant- and microbe-based nanoparticles, which can protect tissues from free radical damage, have recently gained research momentum because they are inexpensive and safe.

CONCLUSION

Synthetic and biocompatible nanoparticles exhibit antioxidant, antidiabetic, anti-inflammatory, and anticancer properties, which can be used to treat several diseases. Further studies are needed to investigate their sizes, dose-dependent activities, and mechanisms of action.

Synthesis and characterization of gold nanoparticles from Abies spectabilis extract and its anticancer activity on bladder cancer T24 cells

In recent times, Gold nanoparticles (AuNPs) synthesized from plant extracts and their anticancer activity have attracted significant attention. We report the green approach for the synthesis of AuNPs using extract from Abies spectabilis plant. In this study, the reaction parameters were optimized to control the size of the nanoparticle, which was confirmed by Transmission Electron microscopy (TEM). Various characterization technique such as SAED pattern, UV visible spectroscopy, EDX, FTIR, and AFM were employed to analyze the synthesized AuNPs obtained from A. spectabilis plant extract. Furthermore, we investigated the anticancer activities using T24 cell lines. Interestingly, the results of extensive screening on the applications of newly synthesized AuNPs were tested for their cytotoxicity effects on anticancer activity against T24 cells by MTT assay. The cell apoptosis was studied using TUNEL, DAPI, caspase activity, cell invasion and migration. Nanoparticles at different concentrations ranging from 1 to 25 μg/ml exhibited a dose dependent cytotoxicity for 24 h. Condensation and DNA fragmentation are characteristic of apoptosis by DAPI, TUNEL staining, and the significant up regulations of Beclin-1, Bax and caspase 3, whereas the expressions of anti-apoptotic Bcl-2 and Bid were down regulated. However, this study, therefore attempts to report the synthesis, characterization, and anticancer activity of gold nanoparticles of A. spectabilis plant extract beneficial for cancer therapeutics.