Biosynthesis of gold nanoparticles by Azospirillum brasilense

Plant-associated nitrogen-fixing soil bacteria Azospirillum brasilense were shown to reduce the gold of chloroauric acid to elemental gold, resulting in formation of gold nanoparticles. Extracellular phenoloxidizing enzymes (laccases and Mn peroxidases) were shown to participate in reduction of Au⁺³ (HAuCl₄) to Au⁰. Transmission electron microscopy revealed accumulation of colloidal gold nanoparticles of diverse shape in the culture liquid of A. brasilense strains Sp245 and Sp7. The size of the electron-dense nanospheres was 5 to 50 nm, and the size of nanoprisms varied from 5 to 300 nm. The tentative mechanism responsible for formation of gold nanoparticles is discussed.     

Biogenic synthesis of floral-shaped gold nanoparticles using a novel strain,Talaromyces flavus

A biogenic route was adopted towards the synthesis of gold nanoparticles using the extract of a novel strain, Talaromyces flavus. Reduction of chloroauric acid by the fungal extract resulted in the production of gold nanoparticle, which was further confirmed by the concordant results obtained from UV–visible spectroscopy, energy dispersive spectroscopy (EDS), and dynamic light scattering (DLS) analysis. Morphology and the crystal nature of the synthesized nanoparticles were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD) and selected area electron diffraction (SAED). A direct correlation was observed between nanoparticle formation and the concentration of reducing agent present in the fungal extract. The time-dependent kinetic study revealed that the bioreduction process follows an autocatalytic reaction. Crystalline, irregular, and mostly flower-shaped gold nanoparticles with a mean hydrodynamic radius of 38.54?±?10.34 nm were obtained. pH played a significant role on production of mono-dispersed nanoparticle. FTIR analysis partially deciphered the involvement of –NH₂, ?SH, and –CO groups as the probable molecules in the bio-reduction and stabilization process. Compared to the conventional methods, a time-resolved, green, and economically viable method for floral-shaped nanoparticle synthesis was developed.     

Mycogenesis of gold nanoparticles using a phytopathogen <Emphasis Type="Italic">Alternaria alternata</Emphasis>

The development of an eco-friendly and reliable process for the synthesis of gold nanomaterials (AuNPs) using microorganisms is gaining importance in the field of nanotechnology. In the present study, AuNPs have been synthesized by bio-reduction of chloroauric acid (HAuCl₄) using the fungal culture filtrate (FCF) of Alternaria alternata. The synthesis of the AuNPs was monitored by UV–visible spectroscopy. The particles thereby obtained were characterized by UV, dynamic light scattering (DLS), X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis, Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM) and transmission electron microscopy (TEM). Energy-dispersive X-ray study revealed the presence of gold in the nanoparticles. Fourier transform infrared spectroscopy confirmed the presence of a protein shell outside the nanoparticles which in turn also support their stabilization. Treatment of the fungal culture filtrate with aqueous Au⁺ ions produced AuNPs with an average particle size of 12 ± 5 nm. This proposed mechanistic principal might serve as a set of design rule for the synthesis of nanostructures with desired architecture and can be amenable for the large scale commercial production and technical applications.     

Carotenoid stabilized gold and silver nanoparticles derived from the Actinomycete Gordonia amicalis HS-11 as effective free radical scavengers

The Actinomycete Gordonia amicalis HS-11 produced orange pigments when cultivated on n-hexadecane as the sole carbon source. When cells of this pigmented bacterium were incubated with 1 mM chloroauric acid (HAuCl₄) or silver nitrate (AgNO₃), pH 9.0, at 25 °C, gold and silver nanoparticles, respectively, were obtained in a cell associated manner. It was hypothesized that the pigments present in the cells may be mediating metal reduction reactions. After solvent extraction and High Performance Liquid Chromatography, two major pigments displaying UV–vis spectra characteristic of carotenoids were isolated. These were identified on the basis of Atmospheric Pressure Chemical Ionization Mass Spectrometry (APCI-MS) in the positive mode as 1′-OH-4-keto-γ-carotene (Carotenoid K) and 1′-OH-γ-carotene (Carotenoid B). The hydroxyl groups present in the carotenoids were eliminated under alkaline conditions and provided the reducing equivalents necessary for synthesizing nanoparticles. Cell associated and carotenoid stabilized nanoparticles were characterized by different analytical techniques. In vitro free radical scavenging activities of cells (control, gold and silver nanoparticle loaded), purified carotenoids and carotenoid stabilized gold and silver nanoparticles were evaluated. Silver nanoparticle loaded cells and carotenoid stabilized silver nanoparticles exhibited improved nitric oxide (NO) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activities compared to their control and gold counterparts. This paper thus reports cell associated nanoparticle synthesis by G. amicalis, describes for the first time the role of carotenoid pigments in metal reduction processes and demonstrates enhanced free radical scavenging activities of the carotenoid stabilized nanoparticles.     

Environmentally benign rapid biosynthesis of extracellular gold nanoparticles using Aspergillus flavus and their cytotoxic and catalytic activities

In this study, the rapid biosynthesis of gold nanoparticles (AuNPs) by Aspergillus flavus culture supernatant was achieved by reducing 1 mM of chloroauric acid (HAuCl₄) within 2 min at pH 7 and 30 °C. The biosynthesized nanoparticles exhibited maximum absorbance at 545 nm in UVvis spectroscopy. Transmission electron microscopy exhibited that AuNPs tend to take nearly spherical shapes with an average size of 12 nm. Fourier transform infrared analysis indicated that carboxyl, amine, and hydroxyl groups may participate in the biosynthesis and stabilization of AuNPs. Its zeta potential was found to be -33.01 mV. Energy dispersive X-rays showed a strong and typical beak of gold nanocrystallites with 80.84 % of analyzed sample. X-Ray diffraction spectrum displayed Bragg reflections identical to the gold nanocrystals. The results confirmed that biosynthesized AuNPs are a potent anticancer agent against A549, HepG2 and MCF7 cell lines with IC₅₀ value 53.5, 60.7 and 100 μg/mL, respectively. Crystal violet assay confirmed the cytopathic effects of AuNPs on HepG2 and A549 cell lines. Annexin-V FITC assay and cell cycle confirmed the apoptotic effect and cell cycle arrest in G2/M phase, respectively for A549 cell line. Moreover, the results showed a degradation efficiency of AuNPs to 4-nitrophenol within 16 min.     

Biosynthesis of nanoparticles of metals and metalloids by basidiomycetes. Preparation of gold nanoparticles by using purified fungal phenol oxidases

The work shows the ability of cultured Basidiomycetes of different taxonomic groups—Lentinus edodes, Pleurotus ostreatus, Ganoderma lucidum, and Grifola frondosa—to recover gold, silver, selenium, and silicon, to elemental state with nanoparticles formation. It examines the effect of these metal and metalloid compounds on the parameters of growth and accumulation of biomass; the optimal cultivation conditions and concentrations of the studied ion-containing compounds for recovery of nanoparticles have been identified. Using the techniques of transmission electron microscopy, dynamic light scattering, X-ray fluorescence and X-ray phase analysis, the degrees of oxidation of the bioreduced elements, the ζ-potential of colloidal solutions uniformity, size, shape, and location of the nanoparticles in the culture fluid, as well as on the surface and the inside of filamentous hyphae have been determined. The study has found the part played by homogeneous chromatographically pure fungal phenol-oxidizing enzymes (laccases, tyrosinases, and Mn-peroxidases) in the recovery mechanism with formation of electrostatically stabilized colloidal solutions. A hypothetical mechanism of gold(III) reduction from HAuCl₄ to gold(0) by phenol oxidases with gold nanoparticles formation of different shapes and sizes has been introduced.

     

Bio-Synthesis of Gold Nanoparticles by <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> and Assessment of Their Conjugation Possibility with Two Types of β-Lactam Antibiotics without Any Additional Linkers

In the present study, biosynthesis of gold nanoparticles (GNPs) by Fusarium oxysporum was carried out and their conjugation possibility with two β-lactam antibiotics was evaluated. F. oxysporum was cultured and the fungal culture supernatant was subjected to the 1 mmol final concentration of chloroauric acid solution. The produced GNPs were analyzed using visible spectrophotometer, X-ray diffraction analysis (XRD) and transmission electron microscope (TEM). After the purification of GNPs, they were subjected to penicillin G and ceftriaxone without any additional linkers. Finally, the mixture was analyzed using visible spectrophotometer, Fourier transform infrared spectroscopy (FTIR) and TEM and subjected to antibacterial activity test using the well diffusion method. Results confirmed the presence of GNPs in the F. oxysporum culture supernatant after the addition of chloroauric acid. TEM results showed that GNPs were spherical and amorphous with sizes around 10–25 nm and XRD confirmed the presence of GNPs in the fungal culture supernatant. After the incubation of GNPs with the antibiotics, FTIR results demonstrated the successful linking of GNPs with the corresponded antibiotics and TEM images showed that GNPs sizes were bigger than the pure ones (around 50–100 nm). Finally the antibacterial activity test indicated that absolutely, the antibacterial properties of the GNPs-β-lactam antibiotics was lowered or not changed in contrast to the pure antibiotics. The present study showed that GNPs had high tendency of conjugation with antibiotics but unlike the previous researches, linking of the antibiotics to GNPs always cannot improve their antibacterial activity based on the antibiotics that were used. The high conjugation affinity of GNPs made them a good candidate as detoxification agent in diverse areas of medicine or environmental sciences.     

Multifunctional Hybrid Fe2O3-Au Nanoparticles for Efficient Plasmonic Heating

One of the most widely used methods for manufacturing colloidal gold nanospherical particles involves the reduction of chloroauric acid (HAuCl₄) to neutral gold Au(0) by reducing agents, such as sodium citrate or sodium borohydride. The extension of this method to decorate iron oxide or similar nanoparticles with gold nanoparticles to create multifunctional hybrid Fe₂O₃-Au nanoparticles is straightforward. This approach yields fairly good control over Au nanoparticle dimensions and loading onto Fe₂O₃. Additionally, the Au metal size, shape, and loading can easily be tuned by changing experimental parameters (e.g., reactant concentrations, reducing agents, surfactants, etc.). An advantage of this procedure is that the reaction can be done in air or water, and, in principle, is amenable to scaling up. The use of such optically tunable Fe₂O₃-Au nanoparticles for hyperthermia studies is an attractive option as it capitalizes on plasmonic heating of gold nanoparticles tuned to absorb light strongly in the VIS-NIR region. In addition to its plasmonic effects, nanoscale Au provides a unique surface for interesting chemistries and catalysis. The Fe₂O₃ material provides additional functionality due to its magnetic property. For example, an external magnetic field could be used to collect and recycle the hybrid Fe₂O₃-Au nanoparticles after a catalytic experiment, or alternatively, the magnetic Fe₂O₃ can be used for hyperthermia studies through magnetic heat induction. The photothermal experiment described in this report measures bulk temperature change and nanoparticle solution mass loss as functions of time using infrared thermocouples and a balance, respectively. The ease of sample preparation and the use of readily available equipment are distinct advantages of this technique. A caveat is that these photothermal measurements assess the bulk solution temperature and not the surface of the nanoparticle where the heat is transduced and the temperature is likely to be higher.     

Biosynthesis of fluorescent gold nanoparticles using an edible freshwater red alga,Lemanea fluviatilis (L.) C.Ag. and antioxidant activity of biomatrix loaded nanoparticles

Biosynthesis of gold nanoparticles has been accomplished via reduction of an aqueous chloroauric acid solution with the dried biomass of an edible freshwater epilithic red alga, Lemanea fluviatilis (L.) C.Ag., as both reductant and stabilizer. The synthesized nanoparticles were characterized by UV–visible, powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), and dynamic light scattering (DLS) studies. The UV–visible spectrum of the synthesized gold nanoparticles showed the surface plasmon resonance (SPR) at around 530 nm. The powder XRD pattern furnished evidence for the formation of face-centered cubic structure of gold having average crystallite size 5.9 nm. The TEM images showed the nanoparticles to be polydispersed, nearly spherical in shape and have sizes in the range 5–15 nm. The photoluminescence spectrum of the gold nanoparticles excited at 300 nm showed blue emission at around 440 nm. Gold nanoparticles loaded within the biomatrix studied using a modified 2,2-diphenyl-1-picrylhydrazyl (DPPH) method exhibited pronounced antioxidant activity.     

Reduction of organic and inorganic selenium compounds by the edible medicinal basidiomycete Lentinula edodes and the accumulation of elemental selenium nanoparticles in its mycelium

We report for the first time that the medicinal basidiomycete Lentinula edodes can reduce selenium from inorganic sodium selenite (Se^IV) and the organoselenium compound 1,5-diphenyl-3-selenopentanedione-1,5 (DAPS-25) to the elemental state, forming spherical nanoparticles. Submerged cultivation of the fungus with sodium selenite or with DAPS-25 produced an intense red coloration of L. edodes mycelial hyphae, indicating accumulation of elemental selenium (Se⁰) in a red modification. Several methods, including transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), and X-ray fluorescence, were used to show that red Se⁰ accumulated intracellularly in the fungal hyphae as electron-dense nanoparticles with a diameter of 180.51±16.82 nm. Under designated cultivation conditions, shiitake did not reduce selenium from sodium selenate (Se^VI).     

Tansy fruit mediated greener synthesis of silver and gold nanoparticles

In this paper we have reported the green synthesis of silver (AgNPs) and gold (AuNPs) nanoparticles by reduction of silver nitrate and chloroauric acid solutions, respectively, using fruit extract of Tanacetum vulgare; commonly found plant in Finland. The process for the synthesis of AgNPs and AuNPs is rapid, novel and ecofriendly. Formation of the AgNPs and AuNPs were confirmed by surface plasmon spectra using UV–Vis spectrophotometer and absorbance peaks at 452 and 546 nm. Different tansy fruit extract concentration (TFE), silver and gold ion concentration, temperature and contact times were experimented in the synthesis of AgNPs and AuNPs. The properties of prepared nanoparticles were characterized by TEM, XRD, EDX and FTIR. Finally zeta potential values at various pH were analyzed along with corresponding SPR spectra.     

Antibacterial activity of silver nanoparticle-coated fabric and leather against odor and skin infection causing bacteria

We present a simple, eco-friendly synthesis of silver and gold nanoparticles using a natural polymer pine gum solution as the reducing and capping agent. The pine gum solution was combined with silver nitrate (AgNO₃) or a chloroauric acid (HAuCl₄) solution to produce silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs), respectively. The reaction process was simple; formation of the nanoparticles was achieved by autoclaving the silver and gold ions with the pine gum. UV–Vis spectra showed surface plasmon resonance (SPR) for silver and gold nanoparticles at 432 and 539 nm, respectively. The elemental forms of AgNPs and AuNPs were confirmed by energy-dispersive X-ray spectroscopy (EDX). Fourier transform infrared spectroscopy (FTIR) showed the biomolecules present in the pine gum, AgNPs, and AuNPs. Transmission electron microscopy (TEM) images showed the shape and size of AgNPs and AuNPs. The crystalline nature of synthesized AgNPs and AuNPs was confirmed by X-ray crystallography [X-ray diffraction (XRD)]. Application of synthesized AgNPs onto cotton fabrics and leather, in order to evaluate their antibacterial properties against odor- or skin infection-causing bacteria, is also discussed. Among the four tested bacteria, AgNP-coated cotton fabric and leather samples displayed excellent antibacterial activity against Brevibacterium linens.     

Counter ions and temperature incorporated tailoring of biogenic gold nanoparticles

Despite the vast research being conducted on the development of biosynthetic procedures, the process is limited owing to the unavailability of modes to control the size and shape of the biosynthesized nanoparticles. In this study, we investigate the size and shape control of gold nanoparticles synthesized by leaf extract of Piper betle (PBE). The effects of various counter ions, temperatures, pH and reaction times on the morphology of gold nanoparticles are also scrutinized. Results from this study indicate that the presence of iodine during biosynthesis leads to the formation of spherical gold nanoparticles and induces the presence of bromine-emanating, truncated nanoplatelets. Spherical nanoparticles are formed with increasing incubation temperature. pH 3 was found to be the optimum for nanoparticles synthesis. The presence of phosphates, sulphates and nitrates increases the productivity of nanoparticles. ICP analysis revealed complete reduction of AuCl₄⁻ ions within 48 h of the reaction. The use of plant extract for rapid synthesis represents a novel and environmentally friendly approach for the fabrication of gold nanoparticles and nanoplatelets, as an alternative to chemical methods.     

Enhanced thermal and ultrasonic stability of a fungal protease encapsulated within biomimetically generated silicate nanospheres

Background

Dendrimers are highly branched synthetic macromolecules with a globular shape. They have been successfully used for generation of nanospheres at mild conditions via biomimetic silicification. Encapsulation of enzyme molecules within these nanospheres during their synthesis is a promising method for rapid and efficient entrapment of several enzymes. However, encapsulation of proteolytic enzymes has been rarely done via biomimetic silicification. As well, the operational stability of encapsulated enzyme has not been systematically reported.

Methods

A proteolytic enzyme, either α-Chymotrypsin or a fungal protease from Aspergilus Oryzea was encapsulated along with iron oxide nanoparticles within particles yielded via biomimetic silicification of different generations of polyamidoamine (PAMAM) dendrimers. Stability of encapsulated enzyme was compared to that of free enzyme during storage at room temperature. As well, their thermal and ultrasonic stabilities were measured. Scanning electron microscopy, transmission electron microscopy and optical microscopy were used to investigate the morphology of nanospheres.

Results

Determination of encapsulation efficiency revealed that ∼ 85% of fungal protease with concentration 1.4 mg mL^− 1 stock solution was immobilized within particles yielded by generation 0. Based on microscopic images the generated particles interconnected with each other and had spherical morphologies independent of generation. Kinetic analysis of encapsulated fungal protease demonstrated that Mechaelis-Menten constant (K_m) slightly increased.

Conclusion

PAMAM dendrimer generation 0 could be effectively used for rapid encapsulation of a fungal protease from Aspegilus Oryzae.

General significance

Encapsulation significantly enhances the thermal and ultrasonic stabilities of enzymes, suggesting a range of diverse applications for them.     

Extracellular synthesis of cuprous selenide nanospheres by a biological‐chemical coupling reduction process in an anaerobic microbial system

Biosynthesis of metal nanoparticles represents a clean, eco‐friendly and sustainable “green chemistry” engineering. Lately, a number of metal selenides were successfully synthesized by biological methods. Here, cuprous selenide (Cu₂Se) nanospheres were prepared under mild conditions by a novel biological‐chemical coupling reduction process. The simple process takes place between EDTA‐Cu and Na₂SeO₃ in presence of an alkaline solution containing NaBH₄ and a selenite‐reducing bacteria, Pantoea agglomerans. It is noteworthy that the isolated Pantoea agglomerans and Cu⁺ ions, where the latter are obtained from reducing Cu²⁺ ions by NaBH₄, play a key role, and Cu⁺ ions not only can promote the generation of Se^2? ions as a catalyst, but also can react with Se^2? ions to form Cu₂Se. XRD pattern, SEM, and TEM images indicated that Cu₂Se nanoparticles were tetragonal crystal structure and the nanospheres diameter were about 100 nm. EDX, UV–vis, and FTIR spectra show that the biosynthesized Cu₂Se nanospheres are wrapped by protein and have a better stability. This work first proposes a new biosynthesis mechanism, and has important reference value for biological preparation of metal selenide nanomaterials. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1264–1270, 2016     

Biosynthesis of extracellular and intracellular gold nanoparticles by Aspergillus fumigatus and A. flavus

Green chemistry is a boon for the development of safe, stable and ecofriendly nanostructures using biological tools. The present study was carried out to explore the potential of selected fungal strains for biosynthesis of intra- and extracellular gold nanostructures. Out of the seven cultures, two fungal strains (SBS-3 and SBS-7) were selected on the basis of development of dark pink colour in cell free supernatant and fungal beads, respectively indicative of extra- and intracellular gold nanoparticles production. Both biomass associated and cell free gold nanoparticles were characterized using X-ray diffractogram (XRD) analysis and transmission electron microscopy (TEM). XRD analysis confirmed crystalline, face-centered cubic lattice of metallic gold nanoparticles along with average crystallite size. A marginal difference in average crystallite size of extracellular (17.76 nm) and intracellular (26 and 22 nm) Au-nanostructures was observed using Scherrer equation. In TEM, a variety of shapes (triangles, spherical, hexagonal) were observed in both extra- and intracellular nanoparticles. 18S rRNA gene sequence analysis by multiple sequence alignment (BLAST) indicated 99 % homology of SBS-3 to Aspergillus fumigatus with 99 % alignment coverage and 98 % homology of SBS-7 to Aspergillus flavus with 98 % alignment coverage respectively. Native-PAGE and activity staining further confirmed enzyme linked synthesis of gold nanoparticles.     

High-level production of animal-free recombinant transferrin from Saccharomyces cerevisiae

Background

Microorganisms that are exposed to pollutants in the environment, such as metals/metalloids, have a remarkable ability to fight the metal stress by various mechanisms. These metal-microbe interactions have already found an important role in biotechnological applications. It is only recently that microorganisms have been explored as potential biofactories for synthesis of metal/metalloid nanoparticles. Biosynthesis of selenium (Se⁰) nanospheres in aerobic conditions by a bacterial strain isolated from the coalmine soil is reported in the present study.

Results

The strain CM100B, identified as Bacillus cereus by morphological, biochemical and 16S rRNA gene sequencing [GenBank:GU551935.1] was studied for its ability to generate selenium nanoparticles (SNs) by transformation of toxic selenite (SeO₃ ^2-) anions into red elemental selenium (Se⁰) under aerobic conditions. Also, the ability of the strain to tolerate high levels of toxic selenite ions was studied by challenging the microbe with different concentrations of sodium selenite (0.5 mM-10 mM). ESEM, AFM and SEM studies revealed the spherical Se⁰ nanospheres adhering to bacterial biomass as well as present as free particles. The TEM microscopy showed the accumulation of spherical nanostructures as intracellular and extracellular deposits. The deposits were identified as element selenium by EDX analysis. This is also indicated by the red coloration of the culture broth that starts within 2-3 h of exposure to selenite oxyions. Selenium nanoparticles (SNs) were further characterized by UV-Visible spectroscopy, TEM and zeta potential measurement. The size of nanospheres was in the range of 150-200 nm with high negative charge of -46.86 mV.

Conclusions

This bacterial isolate has the potential to be used as a bionanofactory for the synthesis of stable, nearly monodisperse Se⁰ nanoparticles as well as for detoxification of the toxic selenite anions in the environment. A hypothetical mechanism for the biogenesis of selenium nanoparticles (SNs) involving membrane associated reductase enzyme(s) that reduces selenite (SeO₃ ^2-) to Se⁰ through electron shuttle enzymatic metal reduction process has been proposed.     

A third-generation H2O2 biosensor based on horseradish peroxidase-labeled Au nanoparticles self-assembled to hollow porous polymeric nanopheres

A novel third-generation biosensor for hydrogen peroxide (H2O2) was developed by self-assembling gold nanoparticles to hollow porous thiol-functionalized poly(divinylbenzene-co-acrylic acid) (DVB-co-AA) nanospheres. At first, a cleaned gold electrode was immersed in hollow porous thiol-functionalized poly(DVB-co-AA) nanosphere latex to assemble the nanospheres, then gold nanoparticles were chemisorbed onto the thiol groups of the nanospheres. Finally, horseradish peroxidase (HRP) was immobilized on the surface of the gold nanoparticles. The immobilized horseradish peroxidase exhibited direct electrochemical behavior toward the reduction of hydrogen peroxide. The resulting biosensor showed a wide linear range of 1.0 microM-8.0mM and a detection limit of 0.5 microM estimated at a signal-to-noise ratio of 3. Moreover, the studied biosensor exhibited high sensitivity, good reproducibility, and long-term stability.     

Unveiling the anticancer and antimycobacterial potentials of bioengineered gold nanoparticles

Synthesis of gold nanoparticles was carried out using Pongammia pinnata (pongam) leaf extract and their anticancer and antimycobacterial activities were studied. Gold nanoparticle formation was confirmed by UV–vis, XRD and HR-TEM. The anticancer efficacies of the biogenic gold nanoparticles were analyzed using cytotoxicity, cell morphology analysis, oxidative DNA damage, apoptosis detection and toxicity studies. Biogenic gold nanoparticles inhibited breast cancer cell line (MCF-7) proliferation with an efficacy of IC₅₀ of 1.85 μg/mL. The antimycobacterial potential of the biogenic gold nanoparticles was screened against M. tuberculosis by Luciferase Reporter Phage (LRP) assay. The gold nanoparticles showed inhibition against sensitive M. tuberculosis with the minimum inhibitory concentration (MIC) of 10 μg/mL whereas no inhibition was found against the rifampicin resistant M. tuberculosis.     

Intracellular Synthesis of Gold Nanoparticles Using an Ectomycorrhizal Strain EM-1083 of <Emphasis Type="Italic">Laccaria fraterna</Emphasis> and Its Nanoanti-quorum Sensing Potential Against <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis>

In this research work different shapes and sizes of gold nanoparticles (AuNPs) were synthesized through an intracellular biogenic approach, exploiting the chloroauric acid reducing and Au⁰ stabilizing potential of Laccaria fraterna EM-1083 mycelia. The intracellularly synthesized AuNPs exhibits anti-quorum sensing inhibitory potential against Pseudomonas aeruginosa. The synthesized AuNPs were characterized using UV–visible spectroscopy; transmission electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy. The characterization proved that the successful synthesis of highly stable crystalline AuNPs with various shapes. Here we tested inhibitory activity of AuNPs on QS-regulated biofilm development and pyocyanin production traits of P. aeruginosa. The qualitative and quantitative data demonstrated that AuNPs significantly inhibited the biofilm formation and pyocyanin production. In summary, our results signify the future use of intracellularly synthesized AuNPs in P. aeruginosa mediated diseases.