Extracellular Synthesis Of Gold Nanoparticles Research Articles

Macroalgae-associated halotolerant marine bacteria Exiguobacterium aestuarii ADCG SIST3 synthesized gold nanoparticles and its anticancer activity in breast cancer cell line (MCF-7)

Marine microorganisms associated with macroalgae have currently been identified as an environmentally safe and efficient technique to use as biofactories in order to produce metal nanoparticles. The current investigation focuses to identify the capability of marine bacteria Exiguobacterium aestuarii ADCG SIST 3 for the extracellular synthesis of gold nanoparticles (AuNPs). The AuNPs that are synthesized were characterized by different techniques and analyzed for their applications in anticancer activity on normal and cancer cells. To the best of our knowledge, this study is first to systematically examine extracellular synthesis of AuNPs by the halotolerant bacteria Exiguobacterium aestuarii ADCG SIST 3 associated with seaweed. The characterization of synthesized AuNPs were carried out using Fourier Transform- Infrared Spectroscopy (FTIR), Raman Spectroscopy, Field Emission Scanning Electron Microscope (FE-SEM),High-Resolution Transmission Electron Microscope (HR-TEM), Particle size analyzer (DLS), Zetasizer, and UV–vis Spectrophotometer. With an average size of 37 nm, the fabricated AuNPs were observed to have a spherical-likemorphology. The cytotoxic response of synthesized AuNPs was assessed by MTT assay on Vero and MCF-7 cell lines. The antioxidant potential of the synthesized AuNPs and apoptosis studies were also carried out which resulted in excellent activity in the MCF-7 cells with potential application in the medical field.

Antiviral Properties of Streptomyces tuirus DBZ39 Mediated Gold Nanoparticles Against Bluetongue virus.

<b>Background and Objective:</b> The proposed study involves the approach from the point of anti-viral activity of gold nanoparticles against the <i>Bluetongue virus</i>. Among viral diseases, Bluetongue is regarded as an economically scouring disease. Neither a vaccine nor an antiviral drug is available for the prevention or treatment of this disease. The antiviral activity of gold nanoparticles synthesized by a novel isolate of <i>Streptomyces tuirus</i> DBZ39 is the breakthrough of the study. <i>Streptomyces tuirus </i>DBZ39, a novel isolate obtained from alkaline soil was proved to be efficient actinomycetes, for the extracellular synthesis of gold nanoparticles. <b>Materials and Methods:</b> An upstream bioprocess was optimized and developed for the synthesis of controlled size gold nanoparticles with solitary mono dispersal pattern in aurum chloride solution. The characterization and confirmation of gold nanoparticles were illustrated by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Analysis (EDAX) and Fourier Transmission Infrared Radiation Analysis (FTIR). <b>Results:</b> Biomass size of 3 g, substrate concentration of 1 mM, pH of 8.5 and temperature of 45°C were observed as optimum conditions for the synthesis of 15-24 nm size gold nanoparticles. The <i>Bluetongue virus</i> (BTV) which belongs to the genus Orbivirus in the family Reoviridae with 26 serotypes is an etiological agent of infectious and non-contagious Bluetongue disease of main sheep and several other domestic animals. <b>Conclusion:</b> Gold nanoparticles for the 1st time, at a higher concentration of 1:64 dilutions revealed a very promising and novel antiviral property against the <i>Bluetongue virus</i>.

Enhanced Extracellular Synthesis of Gold Nanoparticles by Soluble Extracts from Escherichia coli Transformed with Rhizobium tropici Phytochelatin Synthase Gene

Phytochelatins, the enzymatic products of phytochelatin synthase, play a principal role in protecting the plants from heavy metal and metalloid toxicity due to their ability to scavenge metal ions. In the present study, we investigated the capacity of soluble intracellular extracts from E. coli cells expressing R. tropici phytochelatin synthase to synthesize gold nanoparticle. We discovered that the reaction mediated by soluble extracts from the recombinant E. coli cells had a higher yield of gold nanoparticles, compared to that from the control cells. The compositional and morphological properties of the gold nanoparticles synthesized by the intracellular extracts from recombinant cells and control cells were similar. In addition, this extracellular nanoparticle synthesis method produced purer gold nanoparticles, avoiding the isolation of nanoparticles from cellular debris when whole cells are used to synthesize nanoparticles. Our results suggested that phytochelatins can improve the efficiency of gold nanoparticle synthesis mediated by bacterial soluble intracellular extracts, and the potential of extracellular nanoparticle synthesis platform for the production of nanoparticles in large quantity and pure form is worth further investigation.

Extracellular synthesis of gold nanoparticles using the marine bacterium Paracoccus haeundaensis BC74171T and evaluation of their antioxidant activity and antiproliferative effect on normal and cancer cell lines

Green chemistry is beneficial for the production of eco-friendly and stable nanoparticles using biological agents. The present study was performed to explore the potential of the marine bacterium Paracoccus haeundaensis BC74171T for the extracellular synthesis of gold nanoparticles (AuNPs). Cell-free supernatant-mediated AuNPs were characterized by different techniques and analyzed for their antioxidant activity and antiproliferative effect on normal and cancer cells. Visual observations indicated the formation of AuNPs by the development of a ruby red color and were confirmed by a UV–vis absorbance peak at about 535 nm. The synthesized AuNPs were spherical in shape and had an average size of 20.93 ± 3.46 nm, as determined by transmission electron microscopy and a dynamic light scattering particle size analyzer, respectively. From Fourier transform infrared spectroscopy, the interaction of functional groups was determined and the presence of biomaterial on the AuNP surface was confirmed. Concentration-dependent antioxidant activity of AuNPs was observed by the 2,2-diphenyl-1-picrylhydrazyl method. The AuNPs synthesized do not show growth inhibition on HaCaT and HEK293 normal cells, while they show concentration-dependent growth inhibition in the case of A549 and AGS cancer cells. Thereby, this study proves that AuNP synthesis using P. haeundaensis is a facile method and that the AuNPs synthesized are non-toxic to human cells, which indicates that they can be useful in biomedical applications.

Synthesis of AuNPs with catalytic and antioxidant properties using the dreaded weed mimosa

The paper presents a method for the biomimetic extracellular synthesis of gold nanoparticles (AuNPs) by using the aqueous extracts of all the main parts (leaves, stem and roots) of the highly invasive terrestrial weed mimosa (Mimosa pudica). Aqueous extracts of each of these parts served as reducing as well as stabilizing agents. The effects of key variables that influenced the shape and/or size of the AuNPs – mainly metal-extract stoichiometry, temperature and pH – were studied with the help of ultraviolet–visible spectrophotometry, X-ray diffraction, energy-dispersive X-ray spectroscopy, electron microscopy and Fourier transform infrared spectroscopy. The efficacy of the AuNPs in free radical scavenging and as catalyst was witnessed. The studies thus provide a template for scaling up AuNP synthesis and utilizing it. Given the fact that M. pudica is freely available in large quantities, with no other recognized use, the present method opens up a possibility for its large-scale utilization in synthesizing AuNPs of tunable shapes and sizes in a rapid, non-polluting, energy-frugal and inexpensive manner.

BIOSYNTHESIS OF GOLD NANOPARTICLES BY BACTERIA FROM HYPERALKALINE SPRING AND EVALUATION OF THEIR INHIBITORY ACTIVITY AGAINST PYOCYANIN PRODUCTION

Nanoparticles are used in wide range of applications given their unique optical, chemical and electronic properties. Microbial biosynthesis of nanoparticles has offered a milder and eco-friendly alternative to physical and chemical methods of synthesis. One potential use of nanoparticles is for the inhibition of quorum sensing-mediated processes by microorganisms during pathogenic colonization and infection. In this study, bacteria from hyperalkaline spring (pH 11) were isolated using various enrichment media. The isolates, phylogenetically related to Lysinibacillus sp. and Pseudomonas stutzeri, were investigated for their ability to biosynthesize gold nanoparticles (AuNPs) via reduction of chloroauric acid (HAuCl4) at pH 9. Extracellular synthesis of gold nanoparticles was confirmed by UV-Vis absorption analysis which showed a peak at 500-600 nm wavelength range corresponding to the surface plasmon resonance of AuNPs. The AuNPs synthesized were of spherical and irregular shapes as revealed by SEM analysis. The presence of elemental gold was further confirmed by EDX analysis. FTIR results showed that various functional groups are possibly involved in the reduction of HAuCl4 and stabilization of synthesized gold nanoparticles. The inhibitory effect of biosynthesized AuNPs was tested on the growth and pyocyanin production of Pseudomonas aeruginosa PA01 during a 72-hour incubation period. Although the biosynthesized AuNPs showed no toxicity to the test organism, an increasing inhibition level of pyocyanin production was observed with increasing volumes of nanoparticles used. The levels of pyocyanin in setups treated with biosynthesized gold nanoparticles at 10, 30 and 50 L were significantly lower compared to the untreated setups (P ≤ 0.05). Our findings demonstrate that bacteria adapted to alkaline conditions can be used for efficient biosynthesis of AuNPs, which exhibited potential biomedical application in inhibiting pyocyanin production.

Actinomycetes mediated synthesis of gold nanoparticles from the culture supernatant of Streptomyces griseoruber with special reference to catalytic activity.

Biogenic synthesis of nanoparticles has received a tremendous attention from the past few decades. The significant progress in the field of nanotechnology has resulted in a cost-effective and eco-friendly process for nanoparticle synthesis. In the present study, the extracellular synthesis of gold nanoparticles was carried out using culture supernatant of Streptomyces griseoruber, actinomycetes isolated from the soil. Bioreduction of gold nanoparticles was confirmed by UV-visible spectrophotometer that showed the peak between 520 and 550nm. The crystalline nature and mean size of the GNPs were confirmed using XRD. FTIR revealed the possible functional group that could be useful in immobilisation and stabilisation of GNPs. Size and distribution of the biosynthesized GNPs were analysed by HR-TEM that showed the formation of GNPs in the range of 5-50nm. The synthesised GNPs showed good catalytic activity for the degradation of methylene blue. The study shows the rapid and eco-friendly synthesis of GNPs from Streptomyces griseoruber, and this is the first report on the catalytic activity of GNPs from actinomycetes so far.

Bacterial Biosynthesis of Gold Nanoparticles Using Salmonella enterica subsp. enterica serovar Typhi Isolated from Blood and Stool Specimens of Patients

Salmonella is one of the most common causes of gastroenteritis. In this study, a PCR assay was developed for the rapid detection of microbial cultures of Salmonella enterica sub species of enterica serovar Typhi in samples of patients suspected typhoid. The assay was based on duplicate the STY4669-hypothetical protein gene. The gene primers were designed and blast. Then the bacteria strains were employed for the green synthesis of gold nanoparticles (AuNPs), and one of the strains represented ability to extracellular synthesis of gold nanoparticles. The nanoparticles were characterized using UV–visible spectrophotometer, X-ray powder diffraction, Transmission electron microscopy. The synthesized nanoparticles had a maximum absorption in UV–vis spectra at 556 nm, a crystalline structure, and an average size of 42 nm.

Biosynthesis of Gold Nanoparticles and Gold/Prodigiosin Nanoparticles with Serratia marcescens Bacteria

This paper presents the biosynthesis of gold nanoparticles and gold/prodigiosin nanoparticles from the bacterium, Serratia marcescens. The intra- and extra-cellular synthesis of gold nanoparticles is shown to occur over a range of pH and incubation times in cell-free extracts and biomass of Serratia marcescens that were reacted with 2.5 mM tetrachloroauric acid (HAuCl4). The formation of gold nanoparticles was recognized initially via color changes from yellow auro-chloride to shades of red or purple in gold nanoparticle solutions. UV–visible spectroscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy and dynamic light scattering were also used to characterize gold nanoparticles produced within a range of pH conditions. The results show clearly that the production of gold nanoparticles from cell-free extracts require shorter times than the production of gold nanoparticles from the biomass. The implications of the results are also discussed for the processing of gold nanoparticles and gold prodigiosin nanoparticles for localized cancer treatment.

Biosynthesis of gold nanoparticles by Bacillus marisflavi and its potential in catalytic dye degradation

The development of an eco-friendly protocol for the synthesis of nanomaterial is an important aspect of research in nanotechnology. This is the first report describing a greener approach for the extracellular synthesis of gold nanoparticles using Bacillus marisflavi YCIS MN 5. The addition of gold chloride solution into a cell-free extract (CFE) of B. marisflavi resulted in the synthesis of gold nanoparticles at room temperature within 96h. The biosynthesized gold nanoparticles were thoroughly characterized by physicochemical characterization techniques. The synthesized nanoparticles were found to be crystalline and spherical with an average size in the range of ∼14nm. The CFE acted both as reducing and stabilizing agents; hence, no additional capping and the stabilizing agents were needed. These gold nanoparticles were assessed for catalytic reduction of Congo red and methylene blue. It was established that the reduction reaction follows pseudo-first order kinetics with a reaction rate constant of 0.2192and0.2484min−1 for Congo red and methylene blue, respectively. Thus, the synthesized gold nanoparticles were found to show outstanding catalytic activity in the degradation of Congo red and methylene blue. The degraded products were identified by Gas chromatography-mass spectroscopy (GC-MS) after the degradation of Congo red and methylene blue. These results suggest B. marisflavi mediated synthesized gold nanoparticles as a promising nano-catalyst in the degradation of Congo red and methylene blue.

Biosynthesis and antibacterial activity of gold nanoparticles coated with reductase enzymes

Potential of luminescent bacteria in production of metal nanoparticles (NPs) has not been well evaluated up until now. These bacteria contain lux operon which is included of reductase enzymes, by increasing bacterial cell density, the expression of aldehyde synthetic enzymes elevate and enhance the yields of NPs synthesis. Therefore, extracellular synthesis of gold NPs (AuNPs) using natural occurring luminescent bacteria, VLA, VLB, VLC and genetically engineered luminescent bacteria, Pseudomonas putida KT2440 and Pseudomonas fluorescence OS8 have been successfully conducted. NPs were characterised and their antibacterial activity evaluated using microtitre plates at different concentrations against some hospital pathogenic bacteria. Biosynthetic AuNPs produced had maximum absorption at the ranges of 500–550 nanometre wavelengths. Transmission electron microscopy images showed particle sizes between 10 and 50 nanometres and confirmed the success of purification process. The NPs were spherical and the FTIR analysis showed the existence of biomolecules on surface of purified NPs that could be most probably related to reductase enzymes that are stabilised on NPs surfaces. Further investigation on antibacterial properties of these novel NPs which coated by reductase enzymes showed that any increase or decrease in antibacterial activity is dependent on NPs concentration.

Utilizing metal tolerance potential of soil fungus for efficient synthesis of gold nanoparticles with superior catalytic activity for degradation of rhodamine B

In recent years, the surging demand of nanomaterials has boosted unprecedented expansion of research for the development of high yielding and sustainable synthesis methods which can deliver nanomaterials with desired characteristics. Unlike the well-established physico-chemical methods which have various limitations, biological methods inspired by mimicking natural biomineralization processes have great potential for nanoparticle synthesis. An eco-friendly and sustainable biological method that deliver particles with well-defined shape, size and compositions can be developed by selecting a proficient organism followed by fine tuning of various process parameter. The present study revealed high metal tolerance ability of a soil fungus Cladosporium oxysporum AJP03 and its potential for extracellular synthesis of gold nanoparticles. The morphology, composition and crystallinity of nanoparticles were confirmed using standard techniques. The synthesized particles were quasi-spherical in shape with fcc packing and an average particle size of 72.32 ± 21.80 nm. A series of experiments were conducted to study the effect of different process parameters on particle size and yield. Biomass: water ratio of 1:5 and 1 mM precursor salt concentration at physiological pH (7.0) favoured the synthesis of well-defined gold nanoparticles with maximum yield. The as-synthesized nanoparticles showed excellent catalytic efficiency towards sodium borohydride mediated reduction of rhodamine B (2.5 × 10−5 M) within 7 min of reaction time under experimental conditions. Presence of proteins as capping material on the nanoparticle surface was found to be responsible for this remarkable catalytic efficiency. The present approach can be extrapolated to develop controlled and up-scalable process for mycosynthesis of nanoparticles for diverse applications.

Biosynthesis of Gold Nanoparticles with <i>Serratia marcescens </i>Bacteria

This paper presents the biosynthesis of gold nanoparticles from the bacteria, Serratia marcescens.The intra-and extra-cellular synthesis of gold nanoparticles is shown to occur over a range of pH and incubation times in cell-free exracts and biomass ofserratia marcescensthat were reacted with 2.5mM Tetrachloroauric acid (HAuCl4). The formation of gold nanoparticles was identified initially via color changes from yellow auro-chloride to shades of red or purple in gold nanoparticle solutions. UV-Visible spectroscopy (UV-Vis), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray spectroscopy (EDS), Helium Ion Microscopy (HIM) and Dynamic Light Scattering (DLS) were also used to characterize gold nanoparticles produced within a range of pH conditions. The results show clearly that the production of gold nanoparticles from cell-free extracts require shorter times than the production of gold nanoparticles from the biomass.

Biosynthesis of gold nanoparticles by Pseudomonas veronii AS41G inhabiting Annona squamosa L.

Biogenic principles to nanotechnology have generated tremendous attention in recent past owing eco friendly benign process for synthesis of nanoparticles. Present investigation reports extracellular synthesis of gold nanoparticles using cell free supernatant of Pseudomonas veronii AS 41G, a novel endophyte isolated from Annona squamosa L. Gold nanoparticles formation was confirmed with UV–Visible spectrophotometer. FTIR analysis predicted various functional groups responsible for reduction of metal salts and stabilization of gold nanoparticles. Nanoparticles were crystalline in nature as shown in XRD pattern. TEM analysis revealed morphological characteristics of nanoparticles with different size. Thus the present study attributes for facile process for synthesis of gold nanoparticles as an alternative for conventional methods. The study also highlights the new role of novel bacterium Pseudomonas veronii AS41G which will be very valuable as a record for the researchers working on it.

Production of α-amylase for the biosynthesis of gold nanoparticles using Streptomyces sp. MBRC-82

Marine actinobacterial synthesis of gold nanoparticles has good potential to develop simple, cost-effective and eco-friendly methods for production of important biomaterials. In this context, gold nanoparticles have attracted considerable attention in recent years, owing to their various applications. In this paper, we report on the production of α-amylase for the extracellular synthesis of gold nanoparticles using Streptomyces sp. MBRC-82. Medium composition and culture conditions for α-amylase production were statistically optimized. Plackett–Burman design was employed to find out the optimal medium constituents and culture conditions to enhance α-amylase production. Box–Behnken design revealed that three independent variables namely soluble starch (5.8484g), peptone (3.5191g), and NaCl (0.3829) significantly influenced α-amylase production. The gold nanoparticles were characterized by ultraviolet–visible (UV–vis) spectrometer, X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDXA), and transmission electron microscopy (TEM). The particles synthesized using the optimized enzyme activity ranged from 20 to 80nm with an average particle size of 40nm and therefore can be extended to various medicinal applications.

Bioreduction of chloroaurate ions using fruit extract Punica granatum (Pomegranate) for synthesis of highly stable gold nanoparticles and assessment of its antibacterial activity

The design, synthesis and characterisation of biologically synthesised nanomaterials have become an area of significant interest. Presented is a report on the extracellular synthesis of gold nanoparticles using Punica granatum (Pomegranate) fruit extract as the reducing agent to synthesise Au nanoparticles. On treating aqueous chloroauric acid solutions with P. granatum fruit extract, rapid reduction of the chloroaurate ions is observed, leading to the formation of highly stable gold nanoparticles in solution. These nanoparticles showed an absorption peak at 536 nm in the UV–vis spectrum corresponding to the plasmon resonance of gold nanoparticles. Scanning electron microscopy analysis of the gold nanoparticles indicated that they ranged in size from 10 to 50 nm. The Fourier transform infrared spectroscopy spectrum confirmed the presence of main groups occurred in natural plant extract from P. granatum. The synthesised gold nanoparticles were active against Streptobacillus sp. and Escherichia coli.

Mycocrystallization of gold ions by the fungus Cylindrocladium floridanum

The size and morphology determines the thermodynamic, physical and electronic properties of metal nanoparticles. The extracellular synthesis of gold nanoparticles by fungus, Cylindrocladium floridanum, which acts as a source of reducing and stabilizing agent has been described. The synthesized nanoparticles were characterized using techniques such as UV-Vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy, energy dispersive X-ray analysis (EDAX), and high-resolution transmission electron microscopy (HR-TEM). Based on the evidence of HR-TEM, the synthesized particles were found to be spherical with an average size of 19.05 nm. Powder XRD pattern proved the formation of (111)-oriented face-centered cubic crystals of metallic gold. This microbial approach by fungus for the green synthesis of spherical gold nanoparticles has many advantages such as economic viability, scaling up and environment friendliness.

Biosynthesis of Gold Nanoparticles Using Fusarium oxysporum f. sp. cubense JT1, a Plant Pathogenic Fungus.

The development of reliable processes for the synthesis of gold nanoparticles is an important aspect of current nanotechnology research. Recently, reports are published on the extracellular as well as intracellular biosynthesis of gold nanoparticles using microorganisms. However, these methods of synthesis are rather slow. In present study, rapid and extracellular synthesis of gold nanoparticles using a plant pathogenic fungus F. oxysporum f. sp. cubense JT1 (FocJT1) is reported. Incubation of FocJT1 mycelium with auric chloride solution produces gold nanoparticles in 60 min. Gold nanoparticles were characterized by UV-Vis spectroscopy, FTIR, and particle size analysis. The particles synthesized were of 22 nm sized, capped by proteins, and posed antimicrobial activity against Pseudomonas sp.

Extracellular biosynthesis of gold nanoparticles using a gram negative bacterium Pseudomonas fluorescens

ObjectiveIn the present study, the extracellular synthesis of gold nanoparticles were made by making use of Pseudomonas fluorescens. MethodsThe nanoparticles obtained were characterized by UV–vis, transmission electron microscopy (TEM), Scanning electron microscopy (SEM) and FTIR spectroscopy. ResultsSynthesized nanoparticle size ranged from 50–70 nm. FTIR spectrum indicates that the biomolecule cap the nanoparticles. ConclusionsHence the present study enlightens the green chemistry approach on the production of gold nanoparticles using a microorganism. In comparison to chemical synthesis, the synthesis of gold nanoparticles by microbial source is the most reliable method of production and yield.

Phytosynthesis of gold nanoparticles using leaf extract of Coleus amboinicus Lour

Present study reports a green chemistry approach for the biological synthesis of gold nanoparticles by using the leaf extract of Coleus amboinicus Lour. The nanoparticles were structurally characterized by UV–Vis spectroscopy, XRD, TEM and SAED analyses. Elemental and vibrational analyses were done with EDAX and FT–IR spectroscopies respectively. Bioreduction of gold ions by C. amboinicus leaf extract resulted in the synthesis of spherical, truncated triangle, triangle, hexagonal and decahedral nanoparticles. These nanoparticles showed an absorption peak at 536 nm in UV–Vis spectrum corresponding to the plasmon resonance of gold nanoparticles. The size of gold nanoparticles ranged from 4.6 to 55.1 nm. FT–IR spectrum confirmed the involvement of aromatic amines, amide (II) groups and secondary alcohols in capping and reduction of gold nanoparticles. Extracellular synthesis of gold nanoparticles is a simple, cheap and environmentally benign alternative to physical and chemical procedures.