Biogenic AuNPs Research Articles

Biogenic synthesis of gold nanoparticles using Jasminum auriculatum leaf extract and their catalytic, antimicrobial and anticancer activities

Usage of plant sources for the biogenic synthesis of metal nanoparticles is an innovative area in modern nanotechnology research. In the present article, we have reported a trouble-free, environmentally benign approach for the biogenic synthesis of gold nanoparticles (Au NPs) using the Jasminum auriculatum leaf extract, which acts as a stabilising and reducing agents. The surface plasmon resonance peak at 547 nm in the UV–Visible absorption spectrum confirmed the biogenic Au NPs synthesis. TEM & SEM analysis revealed that the biogenic Au NPs are spherical with an average size of 8–37 nm. The catalytic reduction activity on p-nitrophenol revealed that the biogenic Au NPs are a versatile candidate for heterogeneous catalysis. The pH stability study using phosphate buffer solution confirmed the compatibility of our gold nanoparticles for biomedical applications. The cytotoxicity of the biogenic Au NPs revealed that the nanoparticles manifested a significant dose-dependent inhibitory effect in the proliferation of the human cervical cancer cell line with the IC50 value of 104 μg/ml. The biogenic gold nanoparticles showed tremendous antimicrobial commotion against human pathogenic bacteria (Streptococcus pyogenes, Staphylococcus aureus, Escherichia coli and Klebsiella pneumonia) and fungus (Candida albicans, Aspergillus fumigatus, Lecanicillium lecanii and Trichoderma viride).

Green Nanotechnology-based Gold Nanomaterials for Hepatic Cancer Therapeutics: A Systematic Review

The objective of the current study was to systematically review the in-vitro anticancer activity of green synthesized gold nanoparticles (AuNPs) against hepatic cancer cells. The articles were identified through electronic databases, including PubMed, Scopus, Embase, Web of Science, Science Direct, ProQuest, and Cochrane. In total, 20 articles were found eligible to enter into our systematic review. Our findings showed that 65% of the articles used herbal extracts for the synthesis of AuNPs. Significantly, almost all of the articles stated the biofabrication of AuNPs below 100 nm in diameter. Impressively, most of the studies showed significant anticancer activity against HepG2 cells. Molecular studies stated the induction of apoptosis through the AuNPs-treated cells. We provided valuable information about the molecular mechanisms of AuNPs-induced cytotoxicity against HepG2 cells as well as their biocompatibility. The studies represented that AuNPs can be effective as anticancer drug nanocarrier for drug delivery systems. In addition, AuNP surface functionalization provides an opportunity to design multifunctional nanoparticles by conjugating them to diagnostic and/or therapeutic agents for theranostic purposes. Overall, our findings depicted considerable biogenic AuNPs-induced cytotoxicity, however, future studies should assess the anticancer activity of biogenic AuNPs through in-vivo studies, which was missing from such studies.

Emerging Antineoplastic Gold Nanomaterials for Cervical Cancer Therapeutics: A Systematic Review

Cervical cancer, a malignant neoplasm arising from cervix cells, remains one of the leading global cause of women cancer-related deaths. The present study was aimed to conduct a comprehensive systematic review to show the anticancer activity of biological mediated gold nanoparticles (AuNPs) against cervical cancer cells. To identify the articles, a systematic search was performed through the electronic databases including Web of Science, PubMed, Scopus, Science Direct, ProQuest, Embase, and Cochrane for the articles published up to 31 August 2019. Thirty-three articles met our eligibility criteria and were entered into the present systematic review. Our finding showed that twenty-eight articles stated the biogenic AuNPs-induced cytotoxicity against cervical cancer cells, whereas five reports said no cytotoxicity. In this study, the proposed molecular mechanisms of biogenic AuNPs-induced cytotoxicity were discussed. In total, the studies suggested the induction of apoptosis and overgeneration of intracellular reactive oxygen species (ROS) through the AuNPs-treated cervical cells. The information of this study may help the researchers for translation laboratory setting studies to clinical researches. Future investigations are required to represent the efficacy of biogenic AuNPs through in vivo models alone or combination with other anticancer drugs.

Emerging Theranostic Gold Nanomaterials to Combat Lung Cancer: A Systematic Review

Lung cancer remains the significant cause of deaths in males and females worldwide and many attempts have been made for diagnosis and treatment of lung cancer. Nanotechnology has emerged as a novel strategy to design smart nanostructure weapons to combat lung cancer. Recently, the biogenic gold nanoparticles (AuNPs) have attracted highlighted interest for lung cancer theranostics. The current systematic review served to evaluate the anticancer potential of biologically synthesized AuNPs against lung cancer cells through in vitro studies. We provided valuable information regarding the efficacy of biogenic AuNPs suggesting their potential for next generation of anticancer drugs. The articles were identified through international databases involving Cochrane, Web of Science, PubMed, Scopus, Science Direct, ProQuest, and Embase. Eighteen articles were found eligible to enter into the current study. Our findings represented that although some studies reported nontoxicity of biogenic AuNPs against lung cancer cells, most of the studies reported significant anticancer activity of these nanoparticles (NPs) against lung cancer cells. Although the in vitro studies provided preliminary evidence for lung anticancer potential of biogenic AuNPs, further in vivo investigations are required to confirm the efficacy of these NPs through animal models.

Elucidation of synergistic effect of eucalyptus globulus honey and Zingiber officinale in the synthesis of colloidal biogenic gold nanoparticles with antioxidant and catalytic properties

Natural ingredients including plants and biological materials can be used in the synthesis of colloidal gold nanoparticles (AuNPs) to fulfil the needs of safe, biocompatible AuNPs for life science applications. Despite many attempts on green synthesis of AuNPs, stable biogenic AuNPs has yet to be mass produced in the market due to the aggregation of the particles. This study provides a simple one-pot method in synthesising colloidal AuNPs using eucalyptus globulus honey and Zingiber officinale (ginger) as reducing and stabilising agents. The synthesised colloidal AuNPs exhibited well-dispersed spherical morphology with average diameter of 14.5 nm and 14.1 nm for honey-reduced colloidal AuNPs (H6) and honey-reduced/ginger-stabilised colloidal AuNPs (H6G5) respectively. Significant increase in DPPH and hydroxyl radical scavenging activities were found in H6G5 compared to H6 which indicate a prominent antioxidant property of the colloidal AuNPs. The reduction of 4-nitrophenol with the aid of the colloidal AuNPs recorded a reaction time of 28 min and 62 min for H6G5 and H6 respectively compared to 240 min of reaction without the addition of catalyst. The excellent properties of these colloidal AuNPs suggest a simple method for biogenic synthesis. Hence, the synthesised colloidal AuNPs can be further exploited for biomedical and life science applications.

Emerging Theranostic Silver and Gold Nanomaterials to Combat Prostate Cancer: A Systematic Review

Prostate cancer has emerged as the common malignancy in men and is considered as a global issue. Among different strategies to combat prostate cancer, nanobiotechnology appears as a novel approach for prostate cancer theranostics. The current systematic review discussing the recent development in the prostate anticancer activity of biologically synthesized silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) through laboratory investigations. The databases including Cochrane, Web of Science, PubMed, Scopus, Science Direct, ProQuest, and Embase were used to identify the records. It was found that most of the studies used herbal extracts for preparation of AgNPs and/or AuNPs. Majority of biosynthesized nanoparticles (NPs) were formed with spherical morphology. Besides, all studies reported the size of NPs less than 100 nm. Moreover, PC-3 prostate cancer cell was the predominant cell line that was evaluated for prostate anticancer activity of NPs. In the present study, we provided valuable information suggesting the significant prostate anticancer potential of biogenic AgNPs and/or AuNPs. However, further, in vivo investigations are required to provide stronger evidence of the efficacy of bio-mediated synthesized AgNPs and/or AuNPs to combat prostate cancer.

A novel green synthesis of gold nanoparticles using seaweed Lobophora variegata and its potential application in the reduction of nitrophenols

Developing a facile and green approach to synthesize gold nanoparticles (AuNPs) with high catalytic activities for the reduction of toxic nitrophenols to beneficial aminophenols is of tremendous environmental and industrial relevance. The present study reports an environmentally benign synthesis of AuNPs using aqueous extract of seaweed Lobophora variegata as a potential bioreductant. The signatory pinkish red color and a surface Plasmon resonance peak at 530 nm in the UV-Visible spectrum confirmed the formation of AuNPs. TEM images revealed that the biosynthesised AuNPs were spherical in shape with an average size of 11.69 + 2.38 nm. The high crystallinity of the biogenic AuNPs is confirmed from the clear lattice fringes in the High resolution TEM images, bright circular rings in SAED pattern and Bragg’s reflections of (111), (200), and (220) in XRD pattern. FTIR spectra revealed the role of bioactive metabolites in stabilizing the nanoparticles. The report emphasizes the spectroscopic investigation on the efficacy of the biosynthesized AuNPs as excellent catalyst in the reduction of anthropogenic organic pollutants, 4-nitrophenol (4NP), 3-nitrophenol (3NP), and 2-nitrophenol (2NP) to the corresponding aminophenols using NaBH4, which followed a pseudo-first-order kinetics with rate constants in the order k2NP > k4NP > k3NP.

IN VITRO CYTOTOXICITY AND ANTIOXIDANT EVALUATION OF BIOGENIC SYNTHESIZED GOLD NANOPARTICLES FROM MARSILEA QUADRIFOLIA ON LUNG AND OVARIAN CANCER CELLS

Objective: The biogenic gold nanoparticles are considered to be extremely impressive for its wide range of applications in pharmaceutics and therapeutics. The present study was aimed at the biogenic synthesis of gold nanoparticles (AuNPs) from Marsilea quadrifolia aqueous extract and to investigate its antioxidant property and cytotoxic effect on human ovarian teratocarcinoma (PA-1) and lung adenocarcinoma (A549) cell lines.Methods: The biogenic AuNPs was synthesized using an aqueous extract of Marsilea quadrifolia. The synthesized biogenic AuNPs were characterized by ultraviolet (UV) visible spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD). The biogenic AuNPs was assessed for its stability over a period of time and antioxidant activity. The cytotoxicity of biogenic AuNPs against PA-1 and A549 cell lines was studied using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.Results: The synthesized biogenic AuNPs showed peculiar ruby red color and a surface plasmon resonance (SPR) peak at 544 nm in the UV-Vis spectrum. The characterization of biogenic AuNPs by TEM, EDX and XRD revealed well dispersed spherical particles ranging from 10-40 nm and the presence of elemental gold and its crystalline nature, respectively. The AuNPs showed good stability and the scavenging activity at 50 μg/ml. The in vitro cytotoxicity of biogenic AuNPs against PA-1 and A549 cell lines recorded half maximal inhibitory concentration (IC50) of 45.88 μg/ml and 52.015 μg/ml, respectively.Conclusion: The biogenic AuNPs demonstrated superior antioxidant and antiproliferative activities against cancer cell lines.

Optimization of physicochemical parameters in the biofabrication of gold nanoparticles using marine macroalgae Padina tetrastromatica and its catalytic efficacy in the degradation of organic dyes

Green synthesis of metallic nanoparticles by means of renewable bioresources has emerged as a new trend in current nanotechnology research with improved environmental safety. In the current study, monodispersed gold nanoparticles (AuNPs) with excellent stability were prepared in a completely green and cost effective manner using aqueous extract of marine macroalgae-Padina tetrastromatica. The influence of reaction conditions such as the quantity of seaweed extract, temperature, precursor metal ion concentration, reaction time and pH on the biosynthesis of nanoparticle was evaluated spectroscopically and also with the help of high resolution transmission electron microscopy (HR-TEM). These physicochemical parameters not only affected the rate of formation but also the size and morphology of resultant nanoparticles. Optimum conditions resulted in the generation of nearly spherical AuNPs having an average particle size of 11.4 nm. The high crystallinity of the biogenic AuNPs was confirmed from characteristic diffraction peaks in XRD profile, clear lattice fringes in the HR-TEM image and bright circular spots in the SAED pattern. The presence of metallic gold was evidenced from EDAX profile. FTIR study revealed the role of secondary metabolites in the bioreduction as well as stabilization of AuNPs. The study also highlights the spectroscopic investigation on the catalytic efficacy of the biosynthesized AuNPs in the reduction reactions of hazardous organic dyes, eosin yellow and Congo red using sodium borohydride, which have a pseudo-first order kinetics. Thus, the biosynthesized metal nanoparticles using renewable marine resources like seaweeds act as promising materials for the application in environmental protection.Graphical abstract

Cytotoxic and antibacterial activities of biologically synthesized gold nanoparticles assisted by Micrococcus yunnanensis strain J2

Abstract In the present study the capability of Micrococcus yunnanensis J2 (isolated from Sarcheshme mine soil samples and identified by 16S rDNA sequencing) for biosynthesis of gold nanoparticles (Au NPs) was evaluated. The produced biogenic Au NPs were characterized using UV–visible spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD), thermal gravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR) methods. The related TEM and SEM images of biogenic Au NPs indicated spherical shaped and well dispersed nanostructures with the average particle size of 53.8 nm. Zeta potential analysis of as-synthesized Au NPs showed a peak at − 17.6 ± 1.8 mV. The XRD profile of the biogenic Au NPs contained five peaks positioned at 2θ of 38.2°, 45.8°, 63.7°, 77.6°, and 82.1° due to (111), (200), (220), (311), and (222) lattice planes, respectively, which clearly indicated the crystalline structure of the obtained Au NPs. Cytotoxic activity of biologically synthesized Au NPs (assisted by MTT-based colorimetric assay) revealed IC50 (µg/mL) of 73.6 ± 1.9, 85.6 ± 2.9, 63.5 ± 2.1, 65.2 ± 1.9, 105.3 ± 1.7, and 88.4 ± 2.1 against six cancer cell lines of U87, HT1080, PC12, Caco2, MCF7, and A549, respectively. However, two normal cells of 3T3 and Vero inhibited by 85% in the presence of 500 µg/mL of the biogenic Au NPs. Evaluation of antibacterial effect of the produced Au NPs and Au3+ ions against three Gram-positive and four Gram-negative bacterial strains exhibited lower inhibitory activity of Au NPs compared to that of Au3+ ions.

Anti-Helicobacter pylori, anti-diabetic and cytotoxicity activity of biosynthesized gold nanoparticles using Moricandia nitens water extract

This study aims to synthesize gold nanoparticles (AuNPs) using water extract of Moricandia nitens (Viv.) E. A. Durand & Barratte aerial parts water extract. The presence of various phytochemicals viz. alkaloids, carbohydrates, glycosides, flavonoids, tannins, cumarines, protein and saponins by following standard biochemical methods was investigated. The effect of different parameters such as extract concentration, pH and temperature on the size and morphology of the gold nanoparticles (AuNPs) were studied. The synthesized gold nanoparticles (AuNPs) were characterized by using UV-Vis spectroscopy, FTIR and XRD. The synthesized nanoparticles were found to be spherical in shape with average size in the range of 5 to 20 nm. The green synthesized GNPs were found to be potent inhibitors of α-glucosidase with an IC50 value of 159.3 μg/ml and showed anti-Helicobacter pylori activity against multidrug resistant H. pylori strains with an MIC 31.25 (µg/ml). Furthermore, biogenic AuNPS possess more significant anticancer activity against HepG2 and HCT-116 withIC50 =44.6 ± 0.8 µg/ml and IC50 = 36 ± 0.7 µg/ml respectively.

Kokum fruit mediated biogenic gold nanoparticles with photoluminescent, photocatalytic and antioxidant activities

Abstract Biosynthesis of gold nanoparticles (AuNPs) is rapidly emerging area of research and development. In this study, simple, rapid and green method that uses Kokum fruit extract for synthesis of photoluminescent AuNPs with catalytic and antioxidant activities has been reported. For synthesis, the parameters such as 0.6 mM HAuCl4, 1:3 ratio of HAuCl4 to extract, pH 4 and incubation at 80 °C for 15 min were found optimum. The biogenic AuNPs were characterized by UV visible spectroscopy, fourier transform infra-red (FTIR) spectroscopy, energy dispersive X-ray (EDS) spectroscopy, X-ray powder diffraction (XRD) pattern analysis, selected area electron diffraction pattern (SAED) analysis and transmission electron microscope (TEM) imaging. The photoluminescence investigation showed broad excitation band with excitation maximum at 311 nm and emission band with an emission maximum at 455 nm. Noteworthy, the fluorescence emitted by AuNPs was found to be excitation dependent. The investigation of catalytic activity demonstrated that AuNPs possess good photocatalytic activity and could be used for rapid photocatalytic degradation of methylene violet (MV) dye. In addition, AuNPs showed good dose dependent DPPH radical scavenging activity. The proposed method demonstrated that Kokum fruit extract can be used for rapid and green synthesis of photoluminescent AuNPs with catalytic and antioxidant activities.

Plasmonic and fluorescent sensors of metal ions in water based on biogenic gold nanoparticles

Gold nanoparticles (AuNPs) were synthesized using a rapid, single step, and completely green biosynthetic method employing aqueous Citrus paradisi (grapefruit) extract, which was used as both the reducing and capping agent. Au(III) ions were rapidly reduced by the aqueous grapefruit extract, leading to the formation of highly stable and crystalline colloidal AuNPs, confirmed by the surface plasmon resonance (SPR) peak centered at 544 nm in the UV–Vis spectra. Biogenic AuNPs have been evaluated as plasmonic, fluorescent and naked-eye sensors of Pb2+, Ca2+, Hg2+, Zn2+ and Cu2+ ions in aqueous media, with a good performance and selectivity. Of the three methods used for metal ions sensing, fluorescent sensors shows better results, specifically with Ca2+, Cu2+ and Pb2+. Copper was detected by both plasmonic and fluorescent methods.

New insights into microbial-mediated synthesis of Au@biolayer nanoparticles

Our results provide the first direct evidence of a biolayer on biogenic AuNPs and unveil the AuNP biogenic process and mechanisms.

Fermented juices as reducing and capping agents for the biosynthesis of size-defined spherical gold nanoparticles

Gold nanoparticles (AuNPs) are of scientific and industrial significance; however, the traditional synthesis methods employ toxic compounds. Hence, non-toxic and environmentally friendly AuNPs synthesis methods are of special interest. Here, AuNPs were produced using four solutions of fermented grape juices. UV/Vis absorption spectrophotometry and transmission electron microscopy indicated that AuNPs synthesized with a solution based on semi-sweet red grapes were mostly spherical with narrow size distribution (average diameter of 82.1 ± 36.2 nm). AuNPs of similar spherical morphology but smaller size were obtained using a solution based on semi-dry red grapes (57.1 ± 16.4 nm). A large variety of AuNPs shapes and broader size distribution were produced when solutions based on semi-sweet or dry white grapes were applied. In this case, the average sizes of the AuNPs were 271.6 ± 130.2 nm and 76.0 ± 47.2 nm, respectively. Using energy dispersive X-ray spectroscopy, Au, C, and O were detected, confirming formation of biogenic AuNPs in all cases. Mie theory calculations for AuNPs synthesized with the aid of solutions based on red grapes suggest that their optical properties are different and best suited for distinct downstream applications. Attenuated total reflectance Fourier transform infrared spectroscopy, the Folin-Ciocalteu assay, and the Bertrand’s method were used to examine bioactive compounds present in the solutions applied for synthesis. Phenolics, and to a lesser extent reducing sugars, were identified as likely playing a significant role in reduction and stabilization of the AuNPs. These results display the great potential of these solutions for green synthesis of size defined AuNPs, and illustrate that different grape varieties may be used to obtain AuNPs with unique properties.

Biosynthesized colloidal silver and gold nanoparticles as emerging leishmanicidal agents: an insight.

Many recent key innovations in nanotechnology have greatly fascinated scientists to explore new avenues in treatment and diagnosis of emerging diseases. Due to extensive utilization of metallic nanoparticles (NPs)in diverse biomedical applications, scientists are looking forward to green synthesis of NPs as safer, simple, fast, and low-cost method over chemical and physical methods. Due to enriched phytochemistry, no need for maintenance and ready availability, plants are preferred for green synthesis of silver (AgNPs) and gold NPs (AuNPs). Recently, several researchers have exploited these biogenic NPs as potential antileishmanial agents. The current article is focused to mechanistically explain the antileishmanial activity of biogenic AuNPs and AgNPs with a futuristic discussion on the faith of these particles as emerging antileishmanial agents.

Synthesis of extracellular gold nanoparticles using Cupriavidus metallidurans CH34 cells

In this study, spontaneous synthesis of a gold (Au) colloid using cells of Cupriavidus metallidurans CH34 is reported, and compared with results obtained using cells of the model bacterium Escherichia coli MG1655. To investigate the synthesis mechanism, bacterial biomass and secretomes from both strains were incubated with Au(III) ions. Only CH34 cells were capable of producing extracellular dispersions of Au nanoparticles (NPs). Transmission electron microscopy images showed that AuNPs morphology was dominated by triangular and decahedral nanostructures. Energy dispersive X-ray spectroscopy and Fourier transform infrared spectra showed the presence of sulphur and vibrations associated to proteins. Average AuNPs diameter was obtained by dynamic light-scattering measurements (DLS), NP tracking analysis measurements and analysis of electron microscopy images. Moreover, DLS measurements showed that the biogenic colloid was stable after exposure to ultrasound, high ionic strength and extreme pH conditions. The biogenic AuNPs produced by strain CH34 did not show antibacterial activity, in contrast to biogenic silver NPs. Comparative bioinformatic analysis of genomes from strain CH34 and strain MG1655 showed potential CH34 proteins that may be electron donors during reduction of Au(III) ions. On the basis of these results, a mechanism for the extracellular Au reduction by strain CH34 is proposed.

Antimicrobial efficacy of drug blended biosynthesized colloidal gold nanoparticles from Justicia glauca against oral pathogens: A nanoantibiotic approach

Antimicrobial resistance is a challenging task for researchers to develop new strategies. Green synthesis of AuNPs is an eco-friendly approach, which can be utilized in the microbistatic and microbicidal activities. The current study is focused on Justicia glauca (aqueous leaf extract) mediated AuNPs synthesis at room temperature by treating chloroaurate ions, that shows an antagonistic effect with Azithromycin (AZM) and Clarithromycin (CLR) antibiotics against oral pathogenic bacteria and fungi (Micrococcus luteus, Bacillus subtilis, Staphylococcus aureus, Streptococcus mutans, Lactobacillus acidophilus, Escherichia coli, Pseudomonas aeruginosa, Saccharomyces cerevisiae and Candida albicans). Characterization of green synthesized AuNPs was done by using Ultraviolet-visible (UV-vis) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD) analysis and Energy Dispersive X-ray analysis (EDAX). Biosynthesized AuNPs were stable, hexagonal and spherical shaped with a size ∼32.5 ± 0.25 nm. The AuNPs and drug conjugated AuNPs showed potential antibacterial and antifungal activity against the oral pathogens. Minimum Inhibitory Concentration (MIC) values of biogenic AuNPs were observed in the range of 6.25–25 μg/mL against selected oral pathogens. Overall, we conclude that biogenic drug delivery system for AZM and CLR can be exploited as potential antimicrobial therapy in future, subject to detailed in-vitro and in-vivo cytotoxicity.

A biomimetic synthesis of stable gold nanoparticles derived from aqueous extract of Foeniculum vulgare seeds and evaluation of their catalytic activity

A facile biomimetic approach for the synthesis of gold nanoparticles (AuNPs) using aqueous extract of fennel (Foeniculum vulgare) seeds have been reported in this article. The seeds of F. vulgare are rich in various plant secondary metabolites (phytochemicals) such as polyphenolic acids, flavonoids, and saponins. The phytochemicals of F. vulgare seeds play dual role of reducing and stabilizing agents. The formation of gold nanoparticles was evidenced from the appearance of intense purple color at room temperature with λmax around 550 nm in the UV–Vis absorption spectra. The stable AuNPs were further characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and transmission electron microscopy (TEM) analysis. The synthesized nanoparticles were observed to be polydispersed, spherical and ranged from 10 to 30 nm with an average size of 20 ± 2 nm, as obtained from TEM images. The catalytic activity of gold nanoparticles was investigated by studying the reduction of anthropogenic dyes such as methylene blue (MB) and rhodamine B (Rh-B) with sodium borohydride. Results showed the possible applications of biogenic AuNPs in environment related problems.

Synthesis of phytochemicals-stabilized gold nanoparticles and their biological activities against bacteria and Leishmania

Nanoscale materials have shown promising results in the field of medicine as therapeutic agents and drugs delivery vehicles. In the current study, gold nanoparticles (AuNPs) were prepared by a green and facile method using the aqueous extract of Rhazya stricta decne as a source of reducing and stabilizing agents. The bio-fabricated AuNPs were characterized by UV-visible spectroscopy, X-ray diffraction (XRD), Transmission electron microscopy (TEM) and FTIR spectroscopy. Antimicrobial activities of the biosynthesized AuNPs were tested against Leishmania tropica (HTD7), E. coli and S. aureus. AuNPs were the most effective agents in inhibiting the growth of intra-THP-1 amastigotes at 100 μg/mL concentration (IC50 = 43 μg/mL) after 48-h incubation. In addition, the prepared AuNPs also displayed good activity against E. coli (MIC = 25.0 μg/mL) and Bacillus subtilis (50.0 μg/mL). Interestingly, biogenic AuNPs did not exhibit cytotoxic effect against the THP-1 cells after 24 h exposure. The findings of this study conclude that phytochemicals-stabilized AuNPs could be a safe and effective source of antimicrobial agents.