Facile green synthesis of silver nanoparticles using seed aqueous extract of Pistacia atlantica and its antibacterial activity

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.

Current advances in nanocarriers for biomedical research and their applications

Nanodrug delivery systems sometimes referred to as nanocarriers (NCs) are nanoengineered biocompatible materials or devices, which in conjugation with desired bioactive compounds plays an indispensable functional role in the field of pharmaceutical and allied sciences. The diversified ability of this bioengineered colloidal or noncolloidal molecule to breach the biological barriers to reach the targeted location in the biological system uplifts its other versatile natures of mono- or polydispersity in biodistribution. Furthermore, its nontoxicity and biodegradability result in making it a unique candidate for its purpose as drug delivery system. A number of different conjugations of chemical and biological substances are currently implemented for the synthesis of this biofunctional hybrid nanomaterial by simple methods. The use of these bioconjugated as a nanoparticulated system is currently being used for the treatment of various deadly incurable infectious diseases such as tuberculosis and disorders such as diabetes and cancers of various forms. Henceforth, the objective of the present review article is to provide overviews of the diversified and types of nanoparticulated systems, their beneficial as well as deleterious impacts along with the future prospect of nanodrug delivery system based on present status.

SERS study of riboflavin on green-synthesized silver nanoparticles prepared by reduction using different flavonoids: What is the role of flavonoid used?

Spectroscopy of surface-enhanced Raman scattering (SERS) is nowadays widely used in the field of bio-science and medicine. These applications require new enhancing substrates with special properties. They should be non-toxic, environmentally friendly and (bio-) compatible with examined samples. Flavonoids are natural antioxidants with many positive effects on human health. Simultaneously, they can be used as reducing agent in preparation procedure of plasmonic enhancing substrate for SERS spectroscopy. The best amplifiers of Raman vibrational spectroscopic signal are generally silver nanoparticles (AgNPs). In this study, several flavonoids (forming a logical set) were used as reducing agent in AgNPs preparation procedures. Reactivity of 10 structurally arranged flavonoids (namely flavone, chrysin, apigenin, luteolin, tricetin, 3-hydroxyflavone, galangin, kaempferol, quercetin and myricetin) was compared and SERS-activity of prepared AgNPs was tested using model analyte riboflavin. Riboflavin was detected down to concentration 10^-9mol/l.

Antimicrobial and anticancer activities of silver nanoparticles synthesized from the root hair extract of Phoenix dactylifera

There is a continuous rise in the rate of medicine consumption because of the development of drug resistance by microbial pathogens. In the last one decade, silver nanoparticles (AgNPs) have become a remarkable choice for the development of new drugs due to their excellent broad-spectrum antimicrobial activity. In the current piece of work, we have synthesized AgNPs from the root extract of Phoenix dactylifera to test their antimicrobial and anti-cancer potential. UV-visible spectra showed the surface plasmon resonance peak at 420 nm λ_max corresponding to the formation of silver nanoparticles, FTIR spectra further confirmed the involvement of biological moieties in AgNPs synthesis. Moreover, XRD analysis showed the crystalline nature of AgNPs and predicted the crystallite size of 15 to 40 nm. Electron microscopy analyses confirmed their spherical shape. In addition, synthesized AgNPs was also found to control the growth of C. albicans and E. coli on solid nutrient medium with 20 and 22 mm zone of inhibition, respectively. The 100% potency at 40 μg/ml AgNPs concentration was observed against E. coli and C. albicans after 4 h and 48 h incubation respectively. Importantly, AgNPs were also found to decrease the cell viability of MCF7 cell lines in vitro with IC₅₀ values of 29.6 μg/ml and could act as a controlling agent of human breast cancer. Based on our results, we conclude that biologically synthesized AgNPs exhibited multifunctional properties and could be used against human cancer and other infectious diseases.

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.

Hydrogel beads bio-nanocomposite based on Kappa-Carrageenan and green synthesized silver nanoparticles for biomedical applications

This paper describes the fabrication and characterization of bio-nanocomposite hydrogel beads based on Kappa-Carrageenan (κ-Carrageenan) and bio-synthesized silver nanoparticles (Ag-NPs). The silver nanoparticles were prepared in aqueous Citrullus colocynthis seed extract as both reducing and capping agent. Cross-linked κ-Carrageenan/Ag-NPs hydrogel beads were prepared using potassium chloride as the cross-linker. The hydrogel beads were characterized using XRD and FESEM. Moreover, swelling property of the hydrogel beads was investigated. The Ag release profile of the hydrogels was obtained by fitting the experimental data to power law equation. The direct visualization of the green synthesized Ag-NPs using TEM shows particle size in the range of 23±2nm. The bio-nanocomposite hydrogels showed lesser swelling behavior in comparison with pure κ-Carrageenan hydrogel. Regardless the slow Ag release, κ-Carrageenan/Ag-NPs presented good antibacterial activities against Staphylococcus aureus, Methicilin Resistant Staphylococcus aurous, Peseudomonas aeruginosa and Escherichia coli with maximum zones of inhibition 11±2mm. Cytotoxicity study showed that the bio-nanocomposite hydrogels with non-toxic effect of concentration below 1000μg/mL have great pharmacological potential and a suitable level of safety for use in the biological systems.

Mentha arvensis (Linn.)-mediated green silver nanoparticles trigger caspase 9-dependent cell death in MCF7 and MDA-MB-231 cells

INTRODUCTION

Leaf extract of Mentha arvensis or mint plant was used as reducing agent for the synthesis of green silver nanoparticles (GSNPs) as a cost-effective, eco-friendly process compared to that of chemical synthesis. The existence of nanoparticles was characterized by ultraviolet-visible spectrophotometry, dynamic light scattering, Fourier transform infrared spectroscopy, X-ray diffraction, energy-dispersive X-ray analysis, atomic-force microscopy and transmission electron microscopy analyses, which ascertained the formation of spherical GSNPs with a size range of 3-9 nm. Anticancer activities against breast cancer cell lines (MCF7 and MDA-MB-231) were studied and compared with those of chemically synthesized (sodium borohydride [NaBH₄]-mediated) silver nanoparticles (CSNPs).

MATERIALS AND METHODS

Cell survival of nanoparticle-treated and untreated cells was studied by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Cell-cycle analyses were carried out using fluorescence-activated cell sorting. Cell morphology was observed by fluorescence microscopy. Expression patterns of PARP1, P53, P21, Bcl2, Bax and cleaved caspase 9 as well as caspase 3 proteins in treated and untreated MCF7 and MDA-MB-231 cells were studied by Western blot method.

RESULTS

MTT assay results showed that Mentha arvensis-mediated GSNPs exhibited significant cytotoxicity toward breast cancer cells (MCF7 and MDA-MB-231), which were at par with that of CSNPs. Cell cycle analyses of MCF7 cells revealed a significant increase in sub-G1 cell population, indicating cytotoxicity of GSNPs. On the other hand, human peripheral blood lymphocytes showed significantly less cytotoxicity compared with MCF7 and MDA-MB-231 cells when treated with the same dose. Expression patterns of proteins suggested that GSNPs triggered caspase 9-dependent cell death in both cell lines. The Ames test showed that GSNPs were nonmutagenic in nature.

CONCLUSION

GSNPs synthesized using Mentha arvensis may be considered as a promising anticancer agent in breast cancer therapy. They are less toxic and nonmutagenic and mediate caspase 9-dependent apoptosis in MCF7 and MDA-MB-231 cells.

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.

A review on plants extract mediated synthesis of silver nanoparticles for antimicrobial applications: A green expertise

Metallic nanoparticles are being utilized in every phase of science along with engineering including medical fields and are still charming the scientists to explore new dimensions for their respective worth which is generally attributed to their corresponding small sizes. The up-and-coming researches have proven their antimicrobial significance. Among several noble metal nanoparticles, silver nanoparticles have attained a special focus. Conventionally silver nanoparticles are synthesized by chemical method using chemicals as reducing agents which later on become accountable for various biological risks due to their general toxicity; engendering the serious concern to develop environment friendly processes. Thus, to solve the objective; biological approaches are coming up to fill the void; for instance green syntheses using biological molecules derived from plant sources in the form of extracts exhibiting superiority over chemical and/or biological methods. These plant based biological molecules undergo highly controlled assembly for making them suitable for the metal nanoparticle syntheses. The present review explores the huge plant diversity to be utilized towards rapid and single step protocol preparatory method with green principles over the conventional ones and describes the antimicrobial activities of silver nanoparticles.

Sumac silver novel biodegradable nano composite for bio-medical application: antibacterial activity

The development of reliable and ecofriendly approaches for the production of nanomaterials is a significant aspect of nanotechnology nowadays. One of the most important methods, which shows enormous potential, is based on the green synthesis of nanoparticles using plant extract. In this paper, we aimed to develop a rapid, environmentally friendly process for the synthesis silver nanoparticles using aqueous extract of sumac. The bioactive compounds of sumac extract seem to play a role in the synthesis and capping of silver nanoparticles. Structural, morphological and optical properties of the nanoparticles were characterized using FTIR, XRD, FESEM and UV-Vis spectroscopy. The formation of Ag-NP was immediate within 10 min and confirmed with an absorbance band centered at 438 nm. The mean particle size for the green synthesized silver nanoparticles is 19.81 ± 3.67 nm and is fairly stable with a zeta potential value of −32.9 mV. The bio-formed Ag-NPs were effective against E. coli with a maximum inhibition zone of 14.3 ± 0.32 mm.

Formation of plasmonic silver nanoparticles by flavonoid reduction: A comparative study and application for determination of these substances

Formation of plasmonic silver nanoparticles by flavonoid reduction was studied. Effects of the nature and the concentration of a flavonoid and a stabilizer, composition of the solution and the interaction time were revealed. It was found that quercetin, dihydroquercetin, rutin and morin produced an intense surface plasmon resonance band of silver nanoparticles at 415 nm which was linearly related to the concentration of a flavonoid, while chrysin, naringenin and naringin did not produce any remarkable changes. It was used for the spectrophotometric determination of the former four flavonoids with the detection limits of 0.03; 0.06; 0.09 and 0.1 μg mL(-1), respectively. The developed method was applied for the determination of flavonoids in biologically active food additives.