Bio-synthesis of silver nanoparticles using Potentilla fulgens Wall. ex Hook. and its therapeutic evaluation as anticancer and antimicrobial agent

Investigation of the effect of pomegranate extract and monodisperse silver nanoparticle combination on MCF-7 cell line

In this study, we aimed to investigate whether the combination therapy of pomegranate extract and silver nanoparticle is effective on MCF-7 cell culture. The pomegranate extract was mixed and incubated with silver nitrate for the microwave assisted green synthesized of silver nanoparticle. Obtained nanoparticles were investigated using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), UV-vis, Field Emission Scanning Electron Microscopy (FESEM), and Transmission Electron Microscopy (TEM) methods The spectroscopic and morphological studies of the monodisperse Ag NPs which have particle size of 15.4nm indicate the highly crystalline form, well dispersity, and colloidally stable NPs. After fully characterization of prepared nanoparticles, the effectiveness of Ag NPs was determined by evaluating cell viability, nuclear degradation and cell cycle parameters. The results obtained demonstrate that biosynthesized Ag NPs can inhibit the proliferation of human breast cancer cell line MCF-7 in the IC50 at a dose of 12.85μg/mL and inhibit the proliferation of Ag NPs against anti-growth arresting MCF-7 cell line. This case demonstrates that it may exert its proliferative effect by reducing DNA synthesis and apoptosis-inducing cell cycle stages.

Rapid Biological Synthesis of Silver Nanoparticles from Ocimum sanctum and Their Characterization

With development of nanotechnology, the biological synthesis process deals with the synthesis, characterization, and manipulation of materials and further development at nanoscale which is the most cost-effective and eco-friendly and rapid synthesis process as compared to physical and chemical process. In this research silver nanoparticles (AgNPs) were synthesized from silver nitrate (AgNO3) aqueous solution through eco-friendly plant leaf broth of Ocimum sanctum as reactant as well as capping agent and stabilizer. The formation of AgNPs was monitored by ultraviolet-visible spectrometer (UV-vis) and Fourier transform infrared (FTIR) spectroscopy. X-ray diffraction (XRD) and scanning electronic microscopy (SEM) have been used to characterize the morphology of prepared AgNPs. The peaks in XRD pattern are in good agreement with that of face-centered-cubic (FCC) form of metallic silver. Thermal gravimetric analysis/differential thermal analysis (TGA/DTA) results confirmed the weight loss and the exothermic reaction due to desorption of chemisorbed water. The average grain size of silver nanoparticles is found to be 29 nm. The FTIR results indicated that the leaf broths containing the carboxyl, hydroxyl, and amine groups are mainly involved in fabrication of silver AgNPs and proteins, which have amine groups responsible for stabilizing AgNPs in the solution.

Development of temozolomide coated nano zinc oxide for reversing the resistance of malignant glioma stem cells

Recently most of the researchers have turned their interest towards plant mediated synthesis of metal nanoparticles to avoid several environmental toxicants. In this manuscript, we have discussed the ecofriendly syntheses of zinc oxide nanoparticles (ZnO NPs) were achieved using Glycyrrhiza glabra (G. glabra) seed aqueous extract. The green synthesized ZnO NPs were characterized using analytical techniques like XRD, TEM, particle size histogram and Zeta potential. From the results, it was found that the green synthesized ZnO NPs were around 35nm in size with irregular spherical shape. The Zeta potential study of ZnO NPs was resulted to be high stabile with electronegative charge around -56.3mV. Further the G. glabra seed aqueous extract mediated synthesis of ZnO NPs were subjected to treat human glioblastoma cells with the help of temozolomide (TMZ) a commercially available drug by the method of MTT cell viability assay. The results stated that the ZnO NPs shows IC₅₀ value around 30μg/mL results significantly. The plausible mechanism behind the mortality rate was also discussed in this manuscript.

Potential impacts of silver nanoparticles on bacteria in the aquatic environment

It is inevitable that nano-silver will be released into the environment. Therefore, there is an urgent need to better understand the effects of silver nanoparticles (Ag-NPs) on microbes in natural and engineered environments. The most remarkable gap in our knowledge on this lies on the low Ag-NPs dose side. This review summarized studies on the effects of Ag-NPs on bacteria from simple to complicated aquatic systems. A hormetic model with a narrow stimulatory zone has been proposed based on both experimental phenomenon and the potential mechanisms of the observed effects. Spectrum of the stimulating zone depends on Ag-NP properties, bacterial types and environmental conditions tested. This may become a concern in terms of Ag-NP disposal, and further research is required to build a sophisticated toxicity model for Ag-NPs.

Potent bactericidal activity of silver nanoparticles synthesized from Cassia fistula fruit

We demonstrated one-step synthesis of silver nanoparticles (AgNPs) from Cassia fistula fruit extract and their antibacterial activity against E. coli and K. pneumoniae. Biogenic AgNPs were characterized by scanning electron microscopy, X-Ray diffraction and fourier transform infrared spectroscopy. Results confirmed spherical shaped AgNPs with an average crystallite size of ∼69 nm. Dose-dependent (0, 10, 20, 40 and 80 μg mL^-1) growth kinetic studies showed 100% potency against E. coli (20 μg mL^-1) and K. pneumoniae (80 μg mL^-1) after 1 and 5 h, respectively. Surface morphology analysis revealed formation of groove/pits in the lysed cell membrane that eventually led to bacterial death.

Controlled biosynthesis of silver nanoparticles using nitrate reductase enzyme induction of filamentous fungus and their antibacterial evaluation

The controlled synthesis of silver nanoparticles (AgNPs) using cell-free filtrate of Fusarium oxysporum fungus was investigated. The effect of fungal incubation period on nanoparticle formation and nitrate reductase enzyme activity was studied using UV-visible spectroscopy and Harley assay, respectively. The highest AgNP formation was observed in the cell-free filtrate of biomass harvested at the early stationary phase where the NR enzyme activity is the maximum. Mixing of the cell-free filtrates of fungal cultures obtained at 23, 28, and 33 °C with silver nitrate solution confirms the higher productivity of AgNP biosynthesis using the cell-free filtrate of fungus incubated at 28 °C. The effect of some factors such as carbon and nitrate sources and light in fungal incubation period on nitrate reductase induction and AgNP formation was also evaluated. In conclusion, increasing nitrate and carbon sources and presence of light induced NR enzyme and produced AgNPs with smaller size, higher monodispersity, and productivity. Results revealed that the presence of ammonium prevents the NR enzyme secretion and causes to the lower productivity of AgNPs.

Enhanced Antimicrobial and Anticancer Activity of Silver and Gold Nanoparticles Synthesised Using Sargassum incisifolium Aqueous Extracts

A detailed, methodical approach was used to synthesise silver and gold nanoparticles using two differently prepared aqueous extracts of the brown algae Sargassum incisifolium. The efficiency of the extracts in producing nanoparticles were compared to commercially available brown algal fucoidans, a major constituent of brown algal aqueous extracts. The nanoparticles were characterised using TEM, XRD and UV/Vis spectroscopy and zeta potential measurements. The rate of nanoparticle formation was assessed using UV/Vis spectroscopy and related to the size, shape and morphology of the nanoparticles as revealed by TEM. The antioxidant, reducing power and total polyphenolic contents of the aqueous extracts and fucoidans were determined, revealing that the aqueous extracts with the highest contents produced smaller, spherical, more monodisperse nanoparticles at a faster rate. The nanoparticles were assessed against two gram-negative bacteria, two gram-positive bacteria and one yeast strain. In contrast to the literature, the silver nanoparticles produced using the aqueous extracts were particularly toxic to Gram-negative bacteria, while the gold nanoparticles lacked activity. The cytotoxic activity of the nanoparticles was also evaluated against cancerous (HT-29, MCF-7) and non-cancerous (MCF-12a) cell lines. The silver nanoparticles displayed selectivity, since the MCF-12a cell line was found to be resistant to the nanoparticles, while the cancerous HT-29 cell line was found to be sensitive (10% viability). The gold nanoparticles displayed negligible toxicity.

Nitrobacter sp. extract mediated biosynthesis of Ag2O NPs with excellent antioxidant and antibacterial potential for biomedical application

In this study, extracellular extract of plant growth promoting bacterium, Nitrobacter sp. is used for the bioconversion of AgNO3 (silver nitrate) into Ag2O (silver oxide nanoparticles). It is an easy, ecofriendly and single step method for Ag2O NPs synthesis. The bio-synthesized nanoparticles were characterized using different techniques. UV-Vis results showed the maximum absorbance around 450 nm. XRD result shows the particles to have faced centered cubic (fcc) crystalline nature. FTIR analysis reveals the functional groups that are involved in bioconversion such as C-N, N-H and C=O. Energy-dispersive X-ray spectroscopy (EDAX) spectrum confirms that the prepared nanoparticle is Ag2O NPs. Particle size distribution result reveals that the average particle size is around 40 nm. The synthesized Ag2O NPs found to be almost spherical in shape. Biosynthesized Ag2O NPs possess good antibacterial activity against selected Gram positive and Gram negative bacterial strains namely Salmonella typhimurium, Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae when compared to standard antibiotic. In addition, Ag2O NPs exhibits excellent free radical scavenging activity with respect to dosage. Thus, this study is a new approach to use soil bacterial extract for the production of Ag2O NPs for biomedical application.

Plant-Mediated Synthesis of Silver Nanoparticles: Their Characteristic Properties and Therapeutic Applications

Interest in "green nanotechnology" in nanoparticle biosynthesis is growing among researchers. Nanotechnologies, due to their physicochemical and biological properties, have applications in diverse fields, including drug delivery, sensors, optoelectronics, and magnetic devices. This review focuses on the green synthesis of silver nanoparticles (AgNPs) using plant sources. Green synthesis of nanoparticles is an eco-friendly approach, which should be further explored for the potential of different plants to synthesize nanoparticles. The sizes of AgNPs are in the range of 1 to 100 nm. Characterization of synthesized nanoparticles is accomplished through UV spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and scanning electron microscopy. AgNPs have great potential to act as antimicrobial agents. The green synthesis of AgNPs can be efficiently applied for future engineering and medical concerns. Different types of cancers can be treated and/or controlled by phytonanotechnology. The present review provides a comprehensive survey of plant-mediated synthesis of AgNPs with specific focus on their applications, e.g., antimicrobial, antioxidant, and anticancer activities.

Vitis vinifera Assisted Silver Nanoparticles with Antibacterial and Antiproliferative Activity against Ehrlich Ascites Carcinoma Cells

Vitis vinifera extract assisted silver nanoparticles (AgNPs) were biosynthesized that was confirmed primarily by color change and a sharp plasmon absorption band was found at 449 nm. Biosynthesized AgNPs shape was spherical and the particle size of 17 nm in average was confirmed by transmission electron microscopy (TEM) images. Functional groups of AgNPs were identified by Fourier transform infrared spectroscopy (FTIR). Streptococcus aureus was the most sensitive bacteria towards the assisted V. vinifera AgNPs as their growth was 90% inhibited at 100 μg/mL concentration. That was also confirmed by the zone of inhibition study. Up to 96 h, no biofilm was observed for K. pneumoniae at 40 μg/mL of AgNPs. Although AgNPs showed a mild toxicity against brine shrimp nauplii, it showed a remarkable level of antiproliferative activity against Ehrlich ascites carcinoma (EAC) cells.

Rapid Biosynthesis of Silver Nanoparticles Using Pepino (Solanum muricatum) Leaf Extract and Their Cytotoxicity on HeLa Cells

Within nanotechnology, gold and silver nanostructures have unique physical, chemical, and electronic properties [1,2], which make them suitable for a number of applications. Moreover, biosynthetic methods are considered to be a safer alternative to conventional physicochemical procedures for both the environmental and biomedical applications, due to their eco-friendly nature and the avoidance of toxic chemicals in the synthesis. For this reason, employing bio routes in the synthesis of functionalized silver nanoparticles (FAgNP) have gained importance recently in this field. In the present study, we report the rapid synthesis of FAgNP through the extract of pepino (Solanum muricatum) leaves and employing microwave oven irradiation. The core-shell globular morphology and characterization of the different shaped and sized FAgNP, with a core of 20-50 nm of diameter is established using the UV-Visible spectroscopy (UV-vis), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Zeta potential and dynamic light scanning (DLS) studies. Moreover, cytotoxic studies employing HeLa (human cervix carcinoma) cells were undertaken to understand FAgNP interactions with cells. HeLa cells showed significant dose dependent antiproliferative activity in the presence of FAgNP at relatively low concentrations. The calculated IC₅₀ value was 37.5 µg/mL, similar to others obtained for FAgNPs against HeLa cells.

γ-Cyclodextrin capped silver nanoparticles for molecular recognition and enhancement of antibacterial activity of chloramphenicol

Computational studies were conducted to identify the favourable formation of the inclusion complex of chloramphenicol with cyclodextrins. The results of molecular docking and molecular dynamics predicted the strongest interaction of chloramphenicol with γ-cyclodextrin. Further, the inclusion complex of chloramphenicol with γ-cyclodextrin was experimentally prepared and a phenomenon of inclusion was verified by using different characterization techniques such as thermogravimetric analysis, differential scanning calorimetry, (1)H nuclear magnetic resonance (NMR) and two dimensional nuclear overhauser effect spectroscopy (NOESY) experiments. From these results it was concluded that γ-cyclodextrins could be an appropriate cyclodextrin polymer which can be used to functionalize chloramphenicol on the surface of silver nanoparticles. In addition, γ-cyclodextrin capped silver nanoparticles were synthesized and characterized using UV-visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR) and zeta potential analysis. Molecular recognition of chloramphenicol by these cyclodextrin capped silver nanoparticles was confirmed by surface enhanced raman spectroscopy (SERS) experiments. Synergistic antibacterial effect of chloramphenicol with γ-cyclodextrin capped silver nanoparticles was evaluated against Pseudomonas aeruginosa (ATCC 27853), Enterococcus faecalis (ATCC 5129), Klebsiella pneumoniae (ATCC 700603) and Staphylococcus aureus (ATCC 43300). The results from the antibacterial experiment were favourable thus allowing us to conclude that the approach of modifying organic drug molecules with cyclodextrin capped inorganic silver nanoparticles could help to enhance the antibacterial activity of them.

Extract-mediated synthesis of Ag@AgCl nanoparticles using Conium maculatum seeds: characterization, antibacterial activity and cytotoxicity effect against MCF-7 cell line

Silver/silver chloride nanoparticles synthesized using the seed extract of Conium maculatum exhibited considerable antimicrobial activity and cytotoxicity against MCF-7 cell line.

Human colon cancer targeted pro-apoptotic, anti-metastatic and cytostatic effects of binuclear Silver(I)-N-Heterocyclic carbene (NHC) complexes

The current mechanistic study was conducted to explore the effects of increased lipophilicity of binuclear silver(I)-NHC complexes on cytotoxicity. Two new silver(I)-N-Heterocyclic Carbene (NHC) complexes (3 and 4), having lypophilic terminal alkyl chains (Octyl and Decyl), were derived from meta-xylyl linked bis-benzimidazolium salts (1 and 2). Each of the synthesized compounds was characterized by microanalysis and spectroscopic techniques. The complexes were tested for their cytotoxicity against a panel of human cancer c as well normal cell lines using MTT assay. Based on MTT assay results, complex 4 was found to be selectively toxic towards human colorectal carcinoma cell line (HCT 116). Complex 4 was further studied in detail to explore the mechanism of cell death and findings of the study revealed that complex 4 has promising pro-apoptotic and anti-metastatic activities against HCT 116 cells. Furthermore, it showed pronounced cytostatic effects in HCT 116 multicellular spheroid model. Hence, binuclear silver(I)-NHC complexes with longer terminal aliphatic chains have worth to be further studied against human colon cancer for the purpose of drug development.

Nanotoxicology and Metalloestrogens: Possible Involvement in Breast Cancer

As the use of nanotechnology has expanded, an increased number of metallic oxides have been manufactured, yet toxicology testing has lagged significantly. Metals used in nano-products include titanium, silicon, aluminum, silver, zinc, cadmium, cobalt, antimony, gold, etc. Even the noble metals, platinum and cerium, have been used as a treatment for cancer, but the toxicity of these metals is still unknown. Significant advances have been made in our understanding and treatment of breast cancer, yet millions of women will experience invasive breast cancer in their lifetime. The pathogenesis of breast cancer can involve multiple factors; (1) genetic; (2) environmental; and (3) lifestyle-related factors. This review focuses on exposure to highly toxic metals, ("metalloestrogens" or "endocrine disruptors") that are used as the metallic foundation for nanoparticle production and are found in a variety of consumer products such as cosmetics, household items, and processed foods, etc. The linkage between well-understood metalloestrogens such as cadmium, the use of these metals in the production of nanoparticles, and the relationship between their potential estrogenic effects and the development of breast cancer will be explored. This will underscore the need for additional testing of materials used in nano-products. Clearly, a significant amount of work needs to be done to further our understanding of these metals and their potential role in the pathogenesis of breast cancer.

Mycofabricated biosilver nanoparticles interrupt Pseudomonas aeruginosa quorum sensing systems

Quorum sensing (QS) is a chemical communication process that Pseudomonas aeruginosa uses to regulate virulence and biofilm formation. Disabling of QS is an emerging approach for combating its pathogenicity. Silver nanoparticles (AgNPs) have been widely applied as antimicrobial agents against human pathogenic bacteria and fungi, but not for the attenuation of bacterial QS. Here we mycofabricated AgNPs (mfAgNPs) using metabolites of soil fungus Rhizopus arrhizus BRS-07 and tested their effect on QS-regulated virulence and biofilm formation of P. aeruginosa. Transcriptional studies demonstrated that mfAgNPs reduced the levels of LasIR-RhlIR. Treatment of mfAgNPs inhibited biofilm formation, production of several virulence factors (e.g. LasA protease, LasB elastrase, pyocyanin, pyoverdin, pyochelin, rhamnolipid, and alginate) and reduced AHLs production. Further genes quantification analyses revealed that mfAgNPs significantly down-regulated QS-regulated genes, specifically those encoded to the secretion of virulence factors. The results clearly indicated the anti-virulence property of mfAgNPs by inhibiting P. aeruginosa QS signaling.