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Alzheimer's is the most common age-related neurodegenerative disease, characterized by amyloid plaques and intraneuronal neurofibrillary tangles. Nowadays, researchers are considering the use of nanoparticles in the treatment of skin diseases, various injuries and burns, bacterial and fungal infections, and digestive diseases. This research aims to biosynthesis of gold nanoparticles using Bacillus cereus PTCC 1015 and investigate their antioxidant and antiamyloid effects on bovine serum albumin as a model protein. The properties of the synthesized nanoparticles were investigated using UV-vis, FTIR, XRD, TEM, SEM and EDX analyses. The antioxidant and anti-amyloid activities of the synthesized nanoparticles were also evaluated using DPPH and Congo red tests, respectively. Based on electron microscopy images, the synthesized nanoparticles had a spherical morphology with sizes ranging from 20 to 70 nm. The DPPH assay results showed that the synthesized nanoparticles effectively inhibited DPPH free radicals in a concentration-dependent manner, with an IC50 value of 0.8 μg/ml. Furthermore, the anti-amyloid activity results showed that the synthesized nanoparticles have significant potential to inhibit amyloid fibrils, and the highest percentage of inhibition was observed at a concentration of 3.2 μg/ml. The present study demonstrated that B. cereus PTCC 1015 is an effective option for the synthesis of gold nanoparticles. Considering the antioxidant and antiamyloid activities of the synthesized gold nanoparticles, this study represents an important step for further in vivo research. [ABSTRACT FROM AUTHOR]

The specific detection of the type and severity of plant abiotic stresses to take timely measures helps prevent yield reduction. This study introduces a new method to detect the type and severity of stress in rice plants under salinity, drought, and heat conditions by investigating microRNAs. The concentration of eight microRNAs in the tissue of plants subjected to salinity, drought, and heat conditions was measured with the help of an optical biosensor based on gold nanoparticles. The biosensor worked based on probe-target hybridization, in which the mixture of probe/citrate-capped gold nanoparticles (compound 1) and microRNA/polyethyleneimine-capped nanoparticles (compound 2) resulted in the aggregation of nanoparticles and changes in their spectroscopic properties. In the following, machine learning methods were used to predict the type and severity of stress using such concentrations. The results showed that the support vector machine optimized by the genetic algorithm was able to detect the severity of salinity, drought, and heat stress applied to rice plants with appropriate performance and with coefficients of determination of 0.94, 0.91, and 0.86, respectively. Then, the results of feature selection based on the cooperative game theory showed that among the microRNAs studied, miRNA-156, miRNA-393, and miRNA-159 had the largest contribution in predicting drought, salinity, and heat stresses in the rice plants, respectively. The findings of the research show that the examination of plant microRNAs with the help of optical biosensors can lead to reliable features for determining plant growth conditions and plant stresses in the early stage. [ABSTRACT FROM AUTHOR]

In the macro scale, surface forces such as friction and adhesion are of little importance and can be ignored. But in the micro/nano world, these forces are of great importance. For this purpose, in order to simulate the manipulation of nanoparticles based on the atomic force microscope, various friction models can be used, including the HK friction model. Accurate calculation of force and critical time, respectively, in order not to damage the particle and to reach the target point in the manipulation process is important and necessary. In this research, data were collected using the Taguchi test design method in three levels. The amount of force and critical time were calculated for each test. Then, with the help of analysis using the signal-to-noise ratio method, to investigate the effect of the input parameters of the HK friction model including, 1 f, 2 f,B and M The reduction of the critical force and the increase of the critical time in mamipulation the gold nanoparticle with a radius of 50 nm on the silicon oxide substrate have been discussed. Based on the obtained results, parameter B as the first parameter and M as the second parameter with the lowest signal-to-noise ratio on reducing the critical force and with the highest signal-to-noise ratio at the critical time at level 3 with values of -1.869 and -0.3419 [ABSTRACT FROM AUTHOR]

Aflatoxins are important mycotoxins produced by some fungus spp and are resistant to heat treatments such as pasteurization; their concentration remains unchanged, causing threats for humans. In the present study, using differential pulse voltammetry, a pencil graphite electrode based on reduced graphene oxide and gold nanoparticles has been developed to identify aflatoxin in raw camel milk. The behavior of functional electrodes in several processes has been analyzed using cyclic voltammetry and electrochemical impedance spectroscopy. Results showed that stabilization of reduced graphene oxide and gold nanoparticles caused a reduction in current peak and increment in impedance, while by aptamer stabilization and analyte, the current peak has been lowered and impedance increased. According to the differential pulse voltammetry technic, in the 5-800 ng/lit range, electrical current indicated a linear decrease by increasing concentration (R²=0.991). Recovery was 90-94.5% for a produced biosensor in camel milk. The obtained quantitative detection limit was 3ng/lit. Investigation of functional characteristics, including reproducibility and repeatability, expressed acceptable results for a biosensor. [ABSTRACT FROM AUTHOR]

Introduction: Rosemary is one of the most useful medicinal plants among different categories of plants due to its many medicinal properties. Nanoparticles as one of the non-bio-stresses by using their electrochemical properties cause interference in the biosynthetic pathway of compounds in plants. This research was conducted in the form of a completely random basic design with three replications in the agricultural greenhouses of Zanjan University in 2017-2018. Also, gold nanoparticles were produced by the chemical reduction method in the laboratory of University of Zabol, and then their effect on the increase or decrease of compounds in rosemary plant oil was investigated in two time intervals of harvesting: 24 hours, 48 hours, and the control group. Materials and Methods: Rosemary plant cuttings with lengths of 10-12 cm and a diameter of half a centimeter were rooted in small containers containing light, washed soil, and ionolite, and permitted at night temperatures of 10-17 degrees and 21-23 degrees during the day. Then the rooted cuttings were transferred to 5 -liter pots containing a combination of fertile agricultural soil and sand. The Chemical reduction method (sodium citrate) was used to extract nanoparticles (Leopold and Lendl, 2003). The gold nanoparticle mixture that had changed color (blue) was subjected to the absorption spectrum of the spectrophotometric device, and the results obtained from the output of the device were checked based on which the maximum absorption rate of the gold nanoparticle with a diameter of 13 nm is equal to the wavelength of 520 nm and for the gold nanoparticle with a diameter of 52 nm is equal to 533 nm. The samples were sent to Beam Gostar Taban (2016-2021) after extraction by the chemical reduction method for diffraction electron microscopy (SEM) investigations and the authenticity of the presence of gold nanoparticles in the obtained samples. The gold nanoparticle treatment with a concentration of 30 ppm was sprayed on the plant in two different time periods (24 hours and 48 hours) and in the control group (without any treatment group) when the cuttings were fully established in terms of rooting and leafing. After that, their aerial parts were harvested at specified intervals and dried at room temperature for mass spectrometer (GC-MS) analysis. About 400 microliters of effective substance were spectrometered by the device (N Agilent 6890 Agilent technology USA), which was equipped with an ion trap system. The leaf sample of the plant, which was dehydrated at room temperature, was placed in the Cloninger device on a heater for 3 hours at a temperature of 100 degrees Celsius. A Water solvent was used in this research. Results and Discussion: In this study, gold nanoparticles were extracted based on the chemical reduction method, and the synthesis of gold nanoparticles was confirmed by electron microscope diffraction (SEM) and spectrophotometric analyses. The results obtained in this study showed significant changes in the compounds obtained by mass spectrometry (GC-MS) in rosemary oil, each of which has unique medicinal properties. Changes in secondary metabolites increase the plant's antioxidant defenses, which can be important in adapting to stresses._Verbonone is an effective compound in rosemary oil that, in this study, had a significant increase under the treatment of gold nanoparticles. Conclusion: In general, investigations conducted on the expression of oily compounds in rosemary showed that gold nanoparticle treatment did not have a significant effect on all the compounds in rosemary oil, but it was able to significantly increase a number of important compounds. The composition of verbena, which has an anti-inflammatory and antimicrobial role, showed a significant increase in the oily compounds of the rosemary plant. Considering the changes in the important oil compounds of the rosemary plant, it may be possible to induce the maximum production of these compounds and mass production of nanoparticles in the future. [ABSTRACT FROM AUTHOR]

Introduction: Although there are different methods for the production of nanoparticles, today the synthesis of nanoparticles with biological methods has attracted the attention of researchers because it is an easy, environmentally friendly, and cost-effective method. The present study investigates the biosynthesis of gold nanoparticles using Lactobacillus paracasei (MN809528) exopolysaccharide and studies the antibacterial, anti-biofilm, and antioxidant properties.Materials and Methods: For the synthesis of gold nanoparticles, 30 ml of 1% exopolysaccharide (0.1 g) solution was added to an equal volume of 1 mM aqueous HAuCl4 solution and mixed well using stirred (180 rpm) for 48 h at room temperature. The characterization of synthesized gold nanoparticles was performed using UV-VIS, FT-IR, DLS, XRD, EDX, FE-SEM spectroscopic analysis. Antibacterial activity of produced gold nanoparticles by agar well diffusion method, anti-biofilm activity by 96 well microplate dilution method, and antioxidant activity of nanoparticles using DPPH radical adsorption capability were examined.Results: Spectroscopic data showed the presence of a peak at 524 nm, which is specific to gold nanoparticles. Examination of the shape and size of nanoparticles with FE-SEM showed that the produced nanoparticles were spherical in shape and their average size is 2o-50 nm. Antibacterial activity of gold nanoparticles at a concentration of 50 µg /ml was observed against all bacterial tests. However, the highest antibacterial activity was observed against Acinetobacter baumannii (ATCC 17978). In the present study, the gold nanoparticles produced acted as biofilm and DPPH radical inhibitors.Discussion and Conclusion: The results of the study show that Lactobacillus paracasei (MN809528) is a good biological source for the synthesis of gold nanoparticles. The study is the first report on the production of gold nanoparticles by exopolysaccharides isolated from indigenous lactic acid bacteria.

AbstractIn this work, Gold coated iron oxide nanoparticles (MNPs @GLYMS@ Au-NPs) with heat therapy application were synthesized and characterized. Gold cations in the presence of honey as a reducing agent were reduced to gold nanoparticles. The magnetic properties of the modified nanoparticles (VSM) were measured using an equal magnetometer (-35 to +35) emu/g. The presence of Au-S and Fe-O bonds and the Fe3O4 spinel structure were confirmed by the FT-IR (FT-IR) and X-ray diffraction spectrometry (XRD) spectroscopy, respectively. Scanning electron microscopy (SEM) showed the spherical morphology of a surface-modified magnetic nanoparticle with a size of 45-55 nm and the morphology of Fe3O4 nanoparticles were kept after the bonding of the gold nanoparticles. The results of this work showed that nanoparticles have significant magnetic properties and surface functionalized. Because of this nanoparticles provide a useful and important tool creating an acceptable method for improving the quality of hyperthermia due to the production of effective frictional heat and rapid transfer.

Due to fascinating theranostic properties of Gold-nanoparticles and Ga-68 radionuclide, 68Ga was grafted on thioglycolic acid (TGA)-functionalized nano host, in order to target the delivery of the radionuclide to targeted organs. In order to have precise evaluation of the behavior of the labeled nano particles in in-vitro and in-vivo experiments, measurement of the radioactivity in tissue with HPGe detector, and precise quality control tests including RTLC, TEM, PET-Scan, were done as well. Biological information of the nano particles shows outstanding changes in excretion mechanism (increasing urinary tract excretion) and complete transfer of nanoparticles to all vital organs of the rodents. Regarding to the outstanding pharmacokinetics properties of these labeled gold nanoparticles such as proper biodistribution, fast excretion, high structural stability, and proper blood circulation, these labeled nanoparticles can be introduced as a potential candidate for diagnostic PET nuclear imaging.

Introduction: Although there are different methods for the production of nanoparticles, today the synthesis of nanoparticles with biological methods has attracted the attention of researchers because it is an easy, environmentally friendly, and cost-effective method. The present study investigates the biosynthesis of gold nanoparticles using Lactobacillus paracasei (MN809528) exopolysaccharide and studies the antibacterial, anti-biofilm, and antioxidant properties. Materials and Methods: For the synthesis of gold nanoparticles, 30 ml of 1% exopolysaccharide (0.1 g) solution was added to an equal volume of 1 mM aqueous HAuCl4 solution and mixed well using stirred (180 rpm) for 48 h at room temperature. The characterization of synthesized gold nanoparticles was performed using UV-VIS, FT-IR, DLS, XRD, EDX, FE-SEM spectroscopic analysis. Antibacterial activity of produced gold nanoparticles by agar well diffusion method, anti-biofilm activity by 96 well microplate dilution method, and antioxidant activity of nanoparticles using DPPH radical adsorption capability were examined. Results: Spectroscopic data showed the presence of a peak at 524 nm, which is specific to gold nanoparticles. Examination of the shape and size of nanoparticles with FE-SEM showed that the produced nanoparticles were spherical in shape and their average size is 2o-50 nm. Antibacterial activity of gold nanoparticles at a concentration of 50 µg /ml was observed against all bacterial tests. However, the highest antibacterial activity was observed against Acinetobacter baumannii (ATCC 17978). In the present study, the gold nanoparticles produced acted as biofilm and DPPH radical inhibitors. Discussion and Conclusion: The results of the study show that Lactobacillus paracasei (MN809528) is a good biological source for the synthesis of gold nanoparticles. The study is the first report on the production of gold nanoparticles by exopolysaccharides isolated from indigenous lactic acid bacteria. [ABSTRACT FROM AUTHOR]

The present work measured the sign and the amount of nonlinear optical absorption coefficient and nonlinear refractive index of gold nanoparticles by Z-scan method. The Ti: sapphire laser is used in two modes: continuous wave and pulsed with 60 fs duration and a repetition rate of 80 MHz at the wavelength of 800 nm, with an average power of 28 mW. Gold nanoparticles were obtained by the laser ablation method with 20 ns pulses and a repetition rate of 10 Hz in SDS solution. Due to using femtosecond laser pulses with a high repetition rate, thermal and electronic nonlinear effects appeared. The results were compared with a continuous wave Z-scan at the same wavelength and exposure power to eliminate the cumulative thermal effect and separate the electronic and thermal nonlinear coefficients. The electronic and thermal nonlinear absorption coefficients were obtained 15×10-5 and 125×10-5cm.W-1, respectively. Kerr de-focusing effect occurred in both electronic and thermal nonlinearity, and the nonlinear electronic and the thermal refractions were calculated -41×10-9 and -34×10-9cm2W-1, respectively. The experiments show that the nonlinear coefficients of the sample prepared in this research are larger than the values obtained for the samples made by the chemical method.

The use of veterinary drugs, including antibiotics, leads to their aggregation in livestock products such as meat, milk, and eggs. Therefore, rapid, accurate and economy detection of antibiotics for monitoring of food security is necessary. In the current research, a biosensor based on pencil graphite electrode modified with grapheme and gold nanoparticles for detection of β-lactam antibiotic in milk samples was fabricated. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques for evaluation of surface electrode changes were applied. Under optimal conditions, using the EIS method specified that in the ranges of 1×10-15 to 1×10-5 M, The relationship between charge transfer resistance and the logarithm of antibiotic concentration was linear and the regression equation was y=119x+2600 (R²=0.977). The current peaks in three measures were achieved as 18, 19.5 and 19 µA. calculation of relative standard deviation (RSD=3.31%) that indicated an acceptable repeatability for biosensor. For investigating of reproducibility, RDS for current peaks was 8.94% that showed a good reproducibility for biosensor. The selectivity of a biosensor in the presence of three antibiotics including streptomycin, tetracycline, and sulfadiazine was checked. Data of charge transfer resistance was indicated that biosensor has non-significant the response towards the other antibiotics. The results showed that biosensor response decreased by 6% after 18 days compared with the first day, which indicates good stability for biosensor. The percentage recovery range for milk samples at concentrations of 1 × 10-9 and 1× 10-11 M for two samples of cow and sheep milk was obtained as 92.3 to 104% in three replications, which indicates an acceptable recovery range for proposed biosensor.

Introduction: Flaxseed (Linum usitatissimum L.) is a member of the Lamiaceae family used in nutrition, health, and industrial products. Flaxseed accumulates many biologically active compounds, including linolenic acid, linoleic acid, lignans, cyclic peptides, polysaccharides, alkaloids, and cyanogenic glycosides. Recent research suggests that flaxseed lowers cholesterol, stabilizes blood sugar, prevents osteoporosis, helps with weight loss, strengthens the immune system, and prevents cancer. This study aimed to investigate the phytochemical, antioxidant, and phenolic content of extracts of various flaxseed solvents and the biosynthesis of silver and gold nanoparticles using these extracts. Materials & Methods: In order to evaluate the antioxidant power and phenolic content of flaxseeds, flaxseeds extract was extracted using three different solvents, namely ethyl acetate, dichloromethane, and normal hexane by the soxhlet method. Phytochemical tests were used to identify chemical compounds. Following that, for the synthesis of gold and silver nanoparticles, HAuCl4, 3H2O, and AgNO3 salts, as well as dichloromethane extract were used in descending order. Moreover, the characterization of synthesized nanoparticles was performed by various techniques, including UltraViolet-Vis spectrophotometry. Furthermore, transmission electron microscopy and nanoparticle size analysis techniques were used to examine the size and distribution extent of nanoparticles. Ethics code: EE/1400.3.02.4678 /scu.ac.ir Findings: After extracting different extracts of flaxseed, various phytochemical tests and different reagents were used to qualitatively identify the secondary metabolites in the extract. The results showed the presence of flavonoids, alkaloids, and steroids, as well as a lack of tannins and saponins. The highest and lowest phenolic compounds were related to the extract of dichloromethane and n-hexane of flaxseeds, respectively. The highest antioxidant properties for the extract were obtained from flaxseeds using dichloromethane solvent. After the synthesis of gold and silver nanoparticles, the colloidal solutions of the prepared nanoparticles became purple and yellow, respectively. The absorption spectra of the gold and silver nanoparticles showed maximum wavelengths of 525 and 420 nm, respectively, which indicated the characteristic wavelengths for these nanoparticles. Transmission electron microscopy studies showed that the synthesized gold and silver nanoparticles had a spherical shape with uniform distribution and mean diameters of 40 and 90 nm, respectively. Discussion & Conclusions: The results revealed that the use of different solvents was effective for the extraction of total phenolic content. There was also a direct relationship between the amount of total phenol and the results of measuring the antioxidant capacity of the extracts. Moreover, gold and silver nanoparticles were easily prepared using flaxseeds extract.

Abstract Due to the destructive effects of heavy metal ions on human health, providing a simple and inexpensive way to detect and measure them in an aquatic environment is one of the important research areas. In the present work, a simple optical sensor based on gold nanoparticles with chitosan was introduced to detect and measure heavy metal ions in water. These metal ions result in the accumulation of gold-chitosan nanoparticles through the chelating reaction between chitosans and metal ions. The sensitivity of the sensor was investigated for Cu2+, Ni2+, Pb2+, Cd2+ and Hg2+ ions. The results showed that different metal ions cause a different reduction in the plasmon bar. The detection limit for each copper, nickel, lead, cobalt, cadmium and mercury ions was 2.48, 0.27, 0.25, 0.40, 0.28 and 1.43, respectively. This optical sensor showed the most sensitivity to Pb2+ ions. According to the results, this sensor can successfully be used to detect heavy metal ions in water and wastewater samples.

Background: One of the most important complications of toxoplasmosis is its early diagnosis. It seems that GRA7 protein can be a good candidate for detection of the acute phase in Toxoplasmosis. Accordingly, the present study aimed to diagnose toxoplasmosis via a newly immunochromatographic test using recombinant antigen gra7. Methods: The parasite was cultured in mice and then were used for DNA extraction. The gra7 gene was amplified by PCR and cloned into the pET-32a (+) plasmid. Thereafter, the recombinant vector was transferred into the Escherichia coli Rosetta strain and gra7 was detected via SDS-PAGE and western blotting. The bacterial lysate was used to purify the protein by Ni-NTA affinity chromatography .Anti-human gold conjugated antibody, test line and control line were injected to conjugate pad and nitrocellulose membrane, respectively, and all the layer were assembled. By using serum of patients and healthy individuals, manufactured kits were evaluated. Results: Our results indicated that the selected gene was correctly cloned and the protein of interest was produced and purified. The test revealed sensitivity and specificity of 100 and 96.7 percent, respectively. The kit was also shown to be stable over 16 weeks in 37°C. Conclusion: The choice of antigen based on cellular and clinical features of the parasite, as well as the use of previous outcomes yielded to develop a rapid diagnostic test for toxoplasmosis.

In this research, localized surface plasmon resonance spectra for single spherical gold nanoparticles with radius between 20 to 55nm in environments of different refractive indices between 1 and 1.8 has been studied by Finite Different Time Domain method. In this simulations, plasmon resonance frequency is determined for each nanoparticle with optimized mesh size, and is compared with the results of Mie theory. Moreover, using these results, plasmonic propertis of gold nanoshells of various diameters were studied in air (n=1) and water (n=1.33). Plasmon resonance has been calculated for nanoshells and it was concluded that in different environments, gold nanoshells with outer radius of 20 nanometers and diameter of 12 nanometers have their plasmonic spectrum are associated on gold nanosphere with the same outer radius. frequency for nanoshells has been calculated. The plasmon resonance peak shift for various nanoparticles is plotted versus refractive indices. Finally, the most sensitive and most insennitive of nanoparticles to the refractive index of the environment has been discussed for sensing applications.

Milk, from its production to consumption, is exposed to a variety of microbial and chemical contaminants. Aflatoxin M1 (AFM1) is one of the most important contaminants in milk, which has always received attention due to its carcinogenic and destructive effects on the consumer. Accordingly, the rapid, sensitive, and cost- effective identification of AFM1 in milk is essential. In the present paper, an electrochemical aptasensor based on screen printed electrode (SPE) modified with magnetic nanoparticles (MNPs) and gold nanoparticles (AuNPs) was proposed to identify AFM1 in cow milk samples. SPE was activated by applying a potential within the range of -1.5 to +1 V versus the reference electrode at a scan rate of 200 mV/s for 5 continuous cycles in the 0.5 M sulfuric acid and 0.1 M potassium chloride solution. Changes of the electrode surface at different stages of preparation were assessed using cyclic voltammetry (CV) technique. Using CV in optimal conditions, it was found that the aptasensor presents a concentration range of 100-700 ng/l and a limit of detection (LOD) of 50 ng/l. There was a linear relationship between changes of the current peak (∆I) and analyte concentration. This relationship follows the regression equation of ∆I=0.0209C+2.14 (R²=0.9897). Calculation of the relative standard deviation (RSD=3.2%) indicated the acceptable repeatability of the electrochemical aptasensor. The current peak was obtained to be 7.4% in the investigation of RSD reproducibility, indicating the good reproducibility of the electrochemical aptasensor. The obtained results showed that the aptasensor response after 8 days has only reduced by 7% compared to the first day, indicating the desirable stability of the aptasensor. The recovery percentage range for cow milk samples at concentrations of 100 and 200 ng/l was obtained to be 86.5 and 93%, respectively, showing the acceptable recovery percentage of the electrochemical aptasensor. [ABSTRACT FROM AUTHOR]

Background and purpose: Synthesis of homogeneous and equally important nanoparticles is very popular in various sciences. Preparation and use of gold nanoparticles is very important according to their applications in biotechnology. For synthesizing homogeneous gold nanoparticles many substrates and nanostructures have been used. This study aimed at synthesis of gold nanoparticles by apoferritin to be conjugated to antibody for detection of vibrio cholera. Materials and methods: In this study, gold nanoparticles were prepared in apoferritin and compared with apoferritin free gold nanoparticles. Data were characterized by UV-Vis, DLS, and FE-SEM spectroscopy. Results: Findings showed that the synthesized gold nanoparticles in apoferritin are more homogeneous. Conclusion: The distribution of synthesizing gold nanoparticle in presence of apoferritin was so homogenous. In the following step, gold nanoparticles were separated from apoferritin and conjugated to recombinant antibody for detecting vibrio cholera. By bacteria aatchment on gold nanoparticles, red shift ocured on wavelength, which was also visible to naked eyes. So, gold nanoparticles could be considered as a colored biosensor for detection of vibrio cholera.

Designing a biocompatible scaffold that mimics the mechanical, electrical, chemical, and topographical properties of extracellular matrix of the target tissue is one of the main challenges in regulating cellular behaviors. For this reason, conductive scaffolds are very much considered in the engineering of electroactive tissues such as nerve, bone, and heart, and are the ideal tools for transmitting the electrical signals to these tissues and regulating their cells behaviors. On the other hand, nanostructures of conductive polymers have become a topic of interest to many researchers, because by the combination of conductivity and nanostructures, new functional materials are obtained with unique physicochemical properties, which can simultaneously simulate physical and electrical properties of the extracellular matrix. In this regard, several researchers have been working on the design of conductive scaffolds with the consideration of topographical properties. Conductive polymeric nanofibers are prepared using various conductive materials and different methods. Intrinsically conductive polymers, carbon materials such as graphene and carbon nanotubes, and metallic nanoparticles such as gold are the most common materials used for the production of conductive polymer-based nanofibers. This review covers the spinning of conductive polymer or the blend of carrier polymer and conductive agents by electrospinning and wet spinning, conductive agent deposition onto template nanofibers (in situ chemical polymerization, electrochemical polymerization, admicellar polymerization, vapor-phase polymerization, carbon and metal coating on nanofibers through immersion, coating of metal vapor on nanofibers), and template-free synthesis (interface polymerization, electrochemical polymerization) among methods of fabrication of conductive nanofibrous scaffolds and finally their advantages and disadvantages are compared together.

In this method, gold nanoparticles have been synthesized by reducing the gold salt and the Spectrofluorometric spectrum is taken from it. Determination of propranolol is widely used in the treatment of blood pressure and irregular heart beat .The effects of different parameters such as pH; volume of buffer; volume of gold nanoparticles and remaining time are investigated. The results showed that the optimal pH value of 6, 2.5 milliliters as the optimum buffer volume, the optimal volume of gold nanoparticles was 3 milliliters and 6 minutes as the optimum remaining time was determined for specimens and following it the response of the nanoparticles to the drug has been plotted. After determining the calibration curve, it was determined that a very wide linear range of drug can be investigated using this method. The method has been found to have appropriate figure merits. At the end of the study, golden Nano sensor was used in real samples such as blood and urine to measure propranolol and obtained satisfactory results.

Introduction: According to the applications of gold nanoparticle in electronic and medicine, green biological synthesis methods for gold nanoparticle synthesis are considered. Different biological methods cause variant types of metal nanoparticles. Enzymes are one of the powerful tools in this approach. In this study, the role of tyrosinase in gold nanoparticle synthesis was studied by spore displayed tyrosinase. Materials and methods: Bacillus subtilis spore displayed tyrosinase developed in our previous work, was used as an enzyme source for synthesis of Au nanoparticles (AuNPs). X-ray diffraction technique and transmission electron microscopy were used to characterize the nanoparticles. To confirm the role of enzyme in AuNPs synthesis, two types of tyrosinases from Bacillus megaterium and Streptomyces also were studied. Results: The results revealed that AuNPs were produced due to reducing Au3+ to Au0 by spore displayed tyrosinase. These biogenic nanoparticles showed mixed structures including spherical, triangular and hexagonal with the approximate size 2.5 to 35 nm. Furthermore, purified Bacillus megaterium tyrosinase and Streptomyces tyrosinase also produced AuNPs. Discussion and conclusion: The supposed mechanism of Au nanoparticle synthesis by tyrosinase, is electron transferring from copper ions to Au3+. The results represent a green environmental friendly simple method in synthesis AuNPs by spore displayed tyrosinase.

Background and Aims: Although there are several ways of nanoparticles production, however the biological method of nanoparticles production is under attention of researchers due to its eco friendly and energy saving properties. In the present study biosynthesis of gold nanoparticle was done by Fusarium oxysporum fungus strain and the cytotoxicity of the obtained nanoparticles was evaluated in the cell culture. Materials and Methods: Fusarium oxysporum was purchased and cultured in Sabouraud dextrose broth medium. The culture supernatant was subjected to chloroauric acid solution at the final concentration of 1 mM. After nanoparticles production, the color changed reaction mixture was used for characterization with spectrophotometry, XRD and TEM microscopy. The obtained nanoparticles were washed and sterilized. Finally two cell lines (CIRC-HLF as normal and SW 872 as cancerous cell lines) were used for 3-(4,5 dimethyl thiazol-2yl)-2,5 diphenyl tetrazolium bromide (MTT) assay. Results: The fungal supernatant color after 24 hours was changed from yellow to red. TEM images have shown the nanoparticles were spherical or hexagonal and their sizes were around 50-70 nanometer. MTT assay and cell culture assay showed that the produced GNPs had toxic effect when they were used at high concentrations and the CIRC-HLF cell line was more resistant than SW 872 one against the higher concentration of GNPs. Conclusions: It seems that the biological production of gold nanoparticles by Fusarium oxysporum can be done and can be easily produced, washed, sterilized and can be used in vivo.

Determination of antibiotic residues in food including honey is very important. To data, various methods have been developed to determination of antibiotics in honey and other animal products. In recent years, the fabrication of electrochemical biosensors in combination with nanomaterial has attracted much attention. In the present study, an impedometric biosensor based on nanomaterial including reduced oxide grapheme (RGO) and gold nanoparticles (GNP) was developed for antibiotic detection of tetracycline in honey samples. Cyclic voltammetry and electrochemical impedance spectroscopy techniques were used to evaluate the working electrode surface. Peak current values in different modes were 0.034, 0.048, 0.09, 0.020 and 0.015 μA for unmodified electrode, RGO, GNP, aptamer and antibiotic, respectively. Biosensor characteristics including reproducibility, reproducibility, stability, and selectivity were evaluated using resistance charge transfer data, the results showed that they were acceptable. In order to calculate recovery percentage, concentrations of 1×10-9 and 1×10-11 M were prepared from tetracycline and injected into honey samples. The results showed that the proposed biosensor provides 94.1% to 104.4% recovery rate for tetracycline in honey samples. [ABSTRACT FROM AUTHOR]

Single strand DNA or RNA known as aptamers, are able to detect the target molecule with specificity at the monoclonal antibody level. However, the placement of mycotoxins in small molecule groups and their high molecular weight differences with aptamers have become a serious challenge in introducing aptameric probes for them. In the present study, in order to achieve a new and shorter aptameric sequence for aflatoxin B1 (AFB1), an initial oligonucleotide library (Lib1) was designed based on the sequence of a known AFB1 aptamer (named Apt1, 50 bp) using the genetic algorithm. The best aptamer from the Lib1 library was selected based on the molecular docking results and has been modified to create a new library (Lib2) using the truncating strategy. Virtual screening of the Lib2 library in terms of their binding affinity over AFB1 molecule led to obtain the truncated aptamer, C52-T, with 19 bp in length. Type of interaction and stability of C52-T-AFB1 complex were investigated using molecular dynamics simulations (MD) and MM-PBSA method. The affinity constant of C52, C52-T and Apt1 aptamers over AFB1 were estimated through unmodified gold nanoparticle-based colorimetric assay. The experimentally founding and in silico results were completely consistent. It seems that the computational techniques have the great potential to introduce sensitive molecular probes to design specific mycotoxins aptasensors. [ABSTRACT FROM AUTHOR]

- Background: Biological effects of ultrasound waves and their applications in the presence of nanoparticles are a rapidly growing research area. In recent years, ultrasonic therapy of cancer cells has been developed successfully. In this study, effects of ultrasound waves in the presence of gold nanoparticles on the melanoma cells were evaluated. Methods: The Melanoma cells were cultured and divided into 4 groups of control, gold nanoparticle, ultrasound alone and ultrasound waves at the presence of gold nanoparticle. Ultrasound irradiation at intensity of 2 W/cm2 was performed on the cells for 3 minutes. Findings: There was a significant difference in the percent of cell viability between the ultrasound + gold nanoparticles and the other groups. In addition, there was a significant difference between the ultrasound and the control groups, too. Conclusion: Results of this study reveal that ultrasound in the presence of gold nanoparticles can be efficiently used for treatment of melanoma cells; as gold nanoparticles act as cavitation nuclei.

Background and purpose: Synthesis of homogeneous and equally important nanoparticles is very popular in various sciences. Preparation and use of gold nanoparticles is very important according to their applications in biotechnology. For synthesizing homogeneous gold nanoparticles many substrates and nanostructures have been used. This study aimed at synthesis of gold nanoparticles by apoferritin to be conjugated to antibody for detection of vibrio cholera. Materials and methods: In this study, gold nanoparticles were prepared in apoferritin and compared with apoferritin free gold nanoparticles. Data were characterized by UV-Vis, DLS, and FE-SEM spectroscopy. Results: Findings showed that the synthesized gold nanoparticles in apoferritin are more homogeneous. Conclusion: The distribution of synthesizing gold nanoparticle in presence of apoferritin was so homogenous. In the following step, gold nanoparticles were separated from apoferritin and conjugated to recombinant antibody for detecting vibrio cholera. By bacteria aatchment on gold nanoparticles, red shift ocured on wavelength, which was also visible to naked eyes. So, gold nanoparticles could be considered as a colored biosensor for detection of vibrio cholera. [ABSTRACT FROM AUTHOR]

Introduction: Retinoblastoma is a malignant tumor in children. The goal of retinoblastoma treatment is to maintain vision and minimize side effects. In this study, the toxicity of the gold nanoparticle safety in vitro was investigated on an eye tumor of retinoblastoma under in vivo conditions. Materials and Methods: For the evaluation of the toxicity of gold nanoparticles using MTT test after 48 hours in a CO2 incubator at 37 ° C, Y79 cell line was administered under in vitro conditions at concentrations of 1.69, 1.75, 3.5, 7, 14 and 28 μg/ml of gold nanoparticles. Safe dose in vitro was extracted. The toxicity of gold nanoparticles in the treatment of retinoblastoma tumor under in vivo conditions in a rabbit animal model using histochemistry analysis and hemoxin-eosin staining, as well as measuring the cross-sectional area of the tumor using ultrasonic sequential image analysis and extraction using software Image J was studied. Results: The results showed that with increasing the concentration of gold nanoparticles, the percentage of live cells in comparison with the control group had a significant difference (p <0.05) at concentrations greater than 1.69 μg/ml and no significant difference (p> 0.05) in the concentration of 1.69 μg/ml. The results indicated that the injection of gold nanoparticles into the rabbit's eye, with retinoblastoma tumor reduced the size of tumor in the rabbit's eye. Conclusion: It is concluded that the toxicity of gold nanoparticles has a therapeutic effect on Y79 cell line in vitro and in the eye of retinoblastoma tumors in vivo. [ABSTRACT FROM AUTHOR]

In spite of existing of several methods for detection of viruses, time consuming is major limitation of them. So, developing faster and real time method is important to certificate the plant materials in quarantine stations and virus management. In the recent research, nanotechnology was employed to detect Potato virus S (PVS) using gold nanoparticles (AuNPs). Colloidal AuNPs were prepared through citrate reduction and conjugated to a specific antibody against PVS coat protein. Conjugation was optimized by changing the pH of AuNPs and antibody concentration. Antibody coated nanoparticles were used to detect different concentrations of antigen using spectrophotometry. After binding the antibody to the gold nanoparticles which cause an increase in particle size, the SPR peak was displaced in range of 4-5 nm and shifted from 524 to 530 nm. The binding of the antigen to the nanoparticle also caused a change in the particle size and an increase maximum absorbance from 530 to 539 nm. No spectral change were seen when PVY and CMV used as controls. This study is the first attempt of nanoparticle usage in quick and easy detection of PVS. [ABSTRACT FROM AUTHOR]

Introduction: Due to the importance of using nanoparticles in the diseases treatment and diagnosing, it is important to obtain nanoparticles that are more compatible with the body. Because, the biological synthesis of gold nanoparticles is new and novel filed, there is little information on the pharmacokinetics and pharmacodynamics of these particles. Therefore, the present study was conducted to evaluate the possible effects of biological nanoparticles on rat liver. Methods: The nanoparticles were examined on 15 male Wistar rats. For this purpose, the rats were first divided into 3 groups and after two stages of injection of the nanoparticles by intraperitoneal method, their liver was studied by optical microscope. Blood samples from rats collected for biochemical studies. Results: According to the results of the study, in both groups receiving toxic and non-toxic nanoparticles, hepatocyte cells had varicose veins. Additionally, in the recipient group, the doses of sinusoid have a slight distension and hyperemia. Conclusion: Nanoparticles of biological gold have a low toxicity effect on liver tissue in dose dependent manner. [ABSTRACT FROM AUTHOR]

Abstract Background and Objectives: Synthesis of gold nanoparticles is very valuable due to its numerous applications in detection of pathogens, cancer therapy and targeted drug delivery. In this study, the synthesis of gold nanoparticles using Persian clover seed extract as a natural source of both reducing and stabilizing agents, was investigated. Methods: Change of the color of clover seed extract immediately after treatment with hydrogen gold tetrachloride showed the first visible sign of the synthesis of gold nanoparticles. The synthesized nanoparticles were characterizeed using UV visible spectrophotometry, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and transmission electron imaging (TEM). Results: The broad and strong peak of UV visible spectrophotometry at a wavelength of 534 nm indicated the formation of gold nanoparticles. X-ray diffraction pattern confirmed the formation of crystalline structure of gold nanoparticles. The results of Fourier transform infrared spectroscopy showed the involvement of aromatic, amine, and carboxyl groups exist in Persian clover seed extract in the synthesis of gold nanoparticles. Transmission electron image identified the formation of spherical nanoparticles with a size range of 1-30nm and with the most frequency in size of 20-25nm. Synthesized gold nanoparticles remained stable in vitro for up to 2 months with no sediment production or reduction in the frequency of gold nanoparticles. Conclusion: With respect to the results of this study, biosynthesis of gold nanoparticles was very low-cost and without need of energy. The synthesized gold nanoparticles can be used in researches on detection of pathogens, cancer therapy, and targeted drug delivery.

Introduction: The gold nanoparticles as other nanoparticles have catalytic, magnetic, optical, and biological (antimicrobial) properties. On the other hand, resistance to antibiotics is one of the greatest public health problems posed in the world. Therefore, the present study aimed to investigate the antibacterial effects of gold nanoparticles on multi-drug resistant klebsiella pneumoniae as well as escherichia coli and its effect on the liver of balb/c mice. Methods: In this study, multi-drug resistant Klebsiella pneumoniae and Escherichia coli bacteria clinical samples were utilized that were isolated from several hospitals in Isfahan and then the toxic effects of nanoparticles were investigated on the Balb / C mice. Colloidal gold nanoparticles were also applied with spherical shape and a concentration of 200 ppm in size of 10 nm, using two wells and disk agar diffusion method. Antibacterial properties of the nanoparticles were evaluated within 1-3 days with 37 ˚c temperature, and diameter of inhibitory zone of growth was measured every day. Tissue and liver enzymes of the mice were examined, as well. Results: The greatest diameter of inhibitory zone was detected in multi drug resistant E. coli. Most of the MIC and MBC were found in multi-drug resistant Klebsiella pneumoniae bacteria .Gold nanoparticles did not reveal any significant changes on the weight, liver enzymes and liver tissue of Balb / C mice after one month. Conclusion: As the findings of the current study revealed, inhibitory effect of gold nanoparticles was observed on the axamined microorganism. Although the laboratories findings are promising, more studies should be conducted in regard with therapeutic standardization.

Background & objectives: In recent decades, nanotechnology has been developing in medical field, and most of the nanoparticles are highly valuable in hygienic care. Vulvovaginitis is an infectious disease giving rise to problem in genital tract and Candida albicans is the main cause of Vulvovaginitis. Methods: In this study, laboratory effect of gold nanoparticles has been investigated on Candida albicans isolates obtained from patients with Vulvovaginitis. Candida spp. isolates were obtained from 200 patients referring to medical diagnostic laboratory in Isfahan city during 2013, and identified using mycological methods including germ tube, clamydoconidia formation, and culturing on chrom agar media. Antifungal effect of gold nanoparticles was evaluated in concentration of 100, 50, 25, and 12.5 ppm on Candida isolates using well diffusion and microdilution methods. Fluconazole was used as a positive control and results were analyzed by SPSS15 software using Mann-Whitney, Kruskal-Wallis and average differences analysis tests. Results: The most averages of clear zone diameter for gold nanoparticle were 18, 15, 12 millimeter, respectively. Minimum inhibitory and fungicidal concentration of gold nanoparticle was determined 6.25, 12.5 ppm and for fluconazole were 50.25±19.48 and 100.50±38.96, respectively. Based on obtained results antifungal activity of gold nanoparticle was dependent to concentration. Conclusion: In current study, inhibitory effect of gold nanoparticles was evaluated against microorganism. Although the laboratories findings are promising, more investigation should be conducted for therapeutic standardization.

Background: Candida glabrata is one of the most common Candida species which is able to get resistant to antifungals. So, the rapid identification of it, seems to be necessary for early treatment of infections. The conventional methods for detection of Candida species are time-consuming and difficult. Today, using of nanoparticles with unique properties has been expanded. The purpose of this study was rapid identification of Candida glabrata using colorimetric assay based on gold nanoparticles. Methods: Candida glabrata was cultured in yeast extract peptone dextrose broth medium and DNA was extracted. The gene specific sequence (CAGL0M05005g) was determined from the Candida genetic information bank. For polymerase chain reaction (PCR), the primers and probe were designed via Oligo 7 software. The PCR product and probe was affected by denaturation and optimized binding temperatures. The gold nanoparticles were added and changed the color to be visual; by using ultraviolet-visible (UV-vis) spectrophotometer and transmission electron microscopy (TEM), they were confirmed. To evaluate the sensitivity of new method, different concentrations of PCR product were used and the results were analyzed using gel electrophoresis. Findings: The optimum temperatures of the primer binding to the DNA template and hybridization the probe was determined. After adding gold nanoparticles, the mixture solution color was changed from red to purple. The results were confirmed via spectroscopy and electron microscopy. Conclusion: The results indicated that in detection of Candida glabrata, the new method is faster than conventional methods and more sensitive than gel electrophoresis.

نانوذرات طلا از پتانسیل بالایی برای تشخیص، بهبود و درمان سرطان برخوردار هستند. زیست پذیری بالا، تجمع انتخابی در سلول‌های سرطانی و سمیت پایین از جمله مزیت‌های این ذرات می‌باشد. تحقیقات قابل توجهی به استفاده از نانوذرات طلا به عنوان عامل افزایش دهنده‌ی کنتراست تصویربرداری رامان و تصویربرداری پرتو ایکس و نیز عامل گرمادرمانی و افزایش دهنده‌ی حساسیت پرتویی تومور پرداخته است. در مطالعه‌ی حاضر، خصوصیات اپتیکی، فیزیکی و کوانتومی نانوذرات طلا و همچنین چگونگی استفاده از این خصوصیات در زمینه‌های تشخیصی و درمانی سرطان مورد بحث و بررسی قرار گرفته است.

Background and Aims: Although there are several ways of nanoparticles production, however the biological method of nanoparticles production is under attention of researchers due to its eco friendly and energy saving properties. In the present study biosynthesis of gold nanoparticle was done by Fusarium oxysporum fungus strain and the cytotoxicity of the obtained nanoparticles was evaluated in the cell culture. Materials and Methods: Fusarium oxysporum was purchased and cultured in Sabouraud dextrose broth medium. The culture supernatant was subjected to chloroauric acid solution at the final concentration of 1 mM. After nanoparticles production, the color changed reaction mixture was used for characterization with spectrophotometry, XRD and TEM microscopy. The obtained nanoparticles were washed and sterilized. Finally two cell lines (CIRC-HLF as normal and SW 872 as cancerous cell lines) were used for 3-(4,5 dimethyl thiazol-2yl)-2,5 diphenyl tetrazolium bromide (MTT) assay. Results: The fungal supernatant color after 24 hours was changed from yellow to red. TEM images have shown the nanoparticles were spherical or hexagonal and their sizes were around 50- 70 nanometer. MTT assay and cell culture assay showed that the produced GNPs had toxic effect when they were used at high concentrations and the CIRC-HLF cell line was more resistant than SW 872 one against the higher concentration of GNPs. Conclusions: It seems that the biological production of gold nanoparticles by Fusarium oxysporum can be done and can be easily produced, washed, sterilized and can be used in vivo. [ABSTRACT FROM AUTHOR]

Background: One of the nanobiotechnology concepts is application of bio systems for production of nanoparticles. Gold nanoparticles have shown many useful applications especially in medicine. Fungi are the best candidates for the synthesis of gold nanoparticles because of their ability to produce large amount of enzymes. The aim of this study was bioproduction of gold nanoparticles using Penicillium chrysogenum and its antibacterial impact on four common pathogenic bacteria was determined. Methods: Penicillium chrysogenum species isolated from effluent of Isfahan Foulad Mobarake factory. The biomasses of fungi were incubated with HAuCl4 solution in a shaker-incubator for 72 hr, and gold nanoparticles were produced. Production of gold nanoparticles was evaluated by UV-vis spectroscopy and X-ray diffraction. Also antibacterial effect of nanoparticles and fungi extract on 4 pathogenic bacteria including Bacillus subtilis, Staphylococcus areus, Pseudomonas aeroginosa, and Escherichia coli was studied. The minimum inhibitory concentration and minimum bactericidal concentration of the nanoparticles against mentioned bacteria were determined by microdilution method. Results: Synthesis of gold nanoparticles was confirmed by observing the characteristic peak at 532 nm using UV-vis spectroscopy. The XRD analysis also demonstrated that the nanoparticles are in the form of nanocrystaline. Also, it was shown that Penicillium chrysogenum produces intracellular gold nanoparticles in spherical and triangular shapes. Conclusion: Fungus Penicillium chrysogenumis able to produce intracellular gold nanoparticles in the size range of 50-200 nm. [ABSTRACT FROM AUTHOR]

Recent dvances in nanotechnology have enabled us to accumulate high atomic-number nano-materials, such as gold nanoparticles (GNPs), in tumor cells selectively using different techniques and take the advantage of the dose enhancement factor resulting from the presence of such high-Z elements as the vicinity of cancerous cells as a radiosensitizer agent. In this research, the GNPs with an average diameter of 50nm were synthesized and conjugated with folic acid. Different concentrations of this nanoconjugate were incubated with MCF-7 cells for 24 hours and its cytotoxicity was investigated. The results showed that increasing the nanoconjugate concentration up to a critical amount, affects the cells viability. The radiosensitizing effect of the folate nanoconjugate, with a concentration of 50μg/mL, on the MCF-7 cells was assessed under 2Gy of x-ray radiation, generated by an orthhovoltage radiotherapy machine, at various energies of 120, 180, 200 kVp, using the MTT assay. Significant differences in the cell survival were noted among the groups exposed to x-ray radiation with and without the nanoconjugate. A maximum dose enhancement factor of 1.34±0.03 was obtained for the 180kVp X-ray beam. The findings enable us to decrease by one third of the prescribed dose while having the same level of damage to cancer cells. Also, this dose reduction results in lower exposure to the normal tissues located close to the target.

Introduction: Shigella is a Gram-negative enteric bacilli that causes serious problems in advanced and developing countries. The purpose of this study was to evaluate colorimetric assay based on gold nanoparticles for rapid detection of S. flexneri using ipaH gene amplification products. Materials and methods: To identify the genus Shigella, the specific primers were used to amplify ipaH gene with polymerase chain reaction (PCR) method. Then, single-stranded probe was used to connect to the specific region of the PCR product. After addition of gold nanoparticles, the color changing was observed visually in the solution and imaged with scanning electron microscope (SEM). To examine the sensitivity of new method, a range of different concentrations of PCR products was used and the results were compared with gel electrophoresis method. Results: The hybridization of probes with amplified products of ipaH gene caused the accumulation of gold nanoparticles which resulted in color changing in the reaction solution from red to purple, but no color changing was observed in the negative control. Then, the accumulation of gold nanoparticles was approved with SEM. Discussion and conclusion: Because of the specificity of ipaH gene in S. flexneri, the colorimetric assay with high sensitivity can be used for specific detection of S. flexneri in the clinical specimen and food samples. [ABSTRACT FROM AUTHOR]

Background and purpose: Despite relative neutrality of metal gold in chemistry reactions, there is a concern about skin absorption and toxicity of gold nanoparticles that nowadays are increasingly used around us. On the other hand, judging from liver detoxification, in this study, the histological alterations of liver and their enzymes and blood cells were investigated in mice by touch of gold nanoparticles. Material and Methods: The backs of 32 male mice were shaved and then were divided into control group in which their back skins were touched with 0.2ml/day distilled water and 3 groups (25, 50,100 ppm) that were being treated with 0.2 ml/day of gold nanoparticles with mentioned doses and 10 nm diameter for 14 days. Finally, their blood was taken for hematology and biochemistry tests and their livers were removed for histopathology tests. Results: To compare the liver tissues of the control group with 3 other groups showed some abnormalities in liver tissues of all treated groups that in 50 & 100 ppm were significant. The levels of two liver enzymes (ALT,AST) and CBC (complete blood count) of control group in comparison with 3 other groups showed that ALT enzyme levels in 50 &100 ppm groups had increased but the levels of ALT & AST in other groups decreased (not significant) and also the values of CBC test showed no significant differences. Conclusion: Touch of gold nanoparticles and conditions of this study has toxic effect on the liver of male mice. So, this has a hazard potential. [ABSTRACT FROM AUTHOR]

Nanoparticles are dispersed droplets or solid particles with a size of 10-100nm which are made in different shapes. Nanoparticles have received more attention as antiparasitic drugs in recent years since current antiparasitic drugs have some side effects and their efficacy is not proved yet. Nanoparticles are currently used in cancer treatment and gold and silver nanoparticles have a long history in the treatment of rheumatoid arthritis. However, fartoo little attention has been paid to the potential use of gold derivatives against parasitic diseases. In this paper recent developments in the use of gold nanoparticles as anti-parasitic drugs, with emphasis on the major tropical diseases such as Malaria, Leishmaniasis, Schistosomiasis and Trypanosomiasis are reviewed. These diseases affect millions of people worldwide and are involved with many limitations in treatment methods. Some researches indicate that silver nanoparticles, gold, chitosan, and oxidized metals have growth inhibitory or cytotoxic effect on various parasites, including Giardia, Leishmania, Malaria, Toxoplasma and insect larva. Some studies also evaluated the health effects of nanoparticles, such as gold and silver on particular protozoa specially Leishmania and Malaria. Nanoparticles could be used against parasites individually or in combination. Therefore, nanoparticles are recommended for destroying parasites (cytotoxic and inhibitory effect), making more effective and less harmful drugs and also beneficial vaccines for the prevention and control of the parasites. [ABSTRACT FROM AUTHOR]

Background and Objectives: Gold nanoparticles have found many applications in cancer diagnosis and therapy, drug and gene delivery and DNA and protein characterizations. Fungi are extremely good candidates in the synthesis of metal nanoparticles because of their ability to secrete large amounts of enzymes. The aim of this study was biosynthesis of gold nanoparticles by a fungus. Materials and Methods: The sampling was performed from the Ahar copper mine. The biomasses of isolated fungi were incubated with HAuCl4 solution in a shaker-incubator for 72 hr, and the strains that were able to produce gold nanoparticles were identified. The production of gold nanoparticles was studied with UV-vis spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM). Results: Among the eight types of fungi that were isolated from the Ahar copper mine, only Rhizopus oryza was able to synthesize gold nanoparticles. The synthesis of gold nanoparticles was confirmed by observing the characteristic peak at 540 nm using UV-vis spectroscopy. The XRD analysis confirmed that the produced gold nanoparticles are in the form of nanocrystaline. Transmission electron microscopy images showed that Rhizopus oryza produces gold nanoparticles with good monodispersity in spherical and trigonal shapes both intra- and extracellularly. Conclusion: Fungus Rhizopus oryza is able to produce gold nanoparticles in the size range of 10-70 nm. This biologic method has the potential to replace chemical and physical methods currently used for gold nanoparticles production. [ABSTRACT FROM AUTHOR]