Biological Reduction Method Research Articles

Phycosynthesis and characterization of silver nanoparticles produced by biological reduction method using Ulva reticulata Forssk

Phycosynthesis and characterization of silver nanoparticles produced by biological reduction method using Ulva reticulata Forssk

Biosynthesis, characterization, and antifungal activity of plant-mediated silver nanoparticles using Cnidium monnieri fruit extract.

The present study describes a novel method for green synthesis of silver nanoparticles using Cnidium monnieri (CM-AgNPs). Cnidium monnieri fruit is an excellent anti tinea drug that can be used externally to treat superficial fungal infections in the human body. The aqueous ethanolic extract of Cnidium monnieri fruit was prepared and employed in the synthesis of stable silver nanoparticles via biological reduction method. The synthesis conditions of CM-AgNPs was systematically optimized using Box-Behnken design. CM-AgNPs were well characterized by UV-spectroscopy and X-ray powder diffraction (XRD), and it was confirmed that the synthesized particles were AgNPs. The possible functional groups required for the reduction and stabilization of CM-AgNPs in the extract were identified through FTIR spectrum. The size of CM-AgNPs structure was confirmed to be approximately 44.6 nm in polydisperse spherical shape through scanning electron microscopy (SEM), transmission electron microscopy (TEM), and laser dynamic light scattering (DLS). Further, the minimum inhibitory concentration 90% (MIC90) ratios values of Cm-AgNPs against Trichophyton rubrum (7 d), T. mentagrophytes (7 d) and Candida albicans (24 h) were 3.125, 3.125, and 0.78125 μg/mL, respectively, determined by the broth micro dilution method. Finally, the result was concluded that the synthesized AgNPs could be further evaluated in large scale as a potential human topical antifungal agent.

Biosynthesis of silver nanoparticles using tea leaf extract (camellia sinensis) for photocatalyst and antibacterial effect

Silver nanoparticles (C. AgNPs) are synthesized by the biological reduction method using extracts from green tea leaves (Camellia Sinensis) collected from tea hills at an altitude of 100 m above the ground. The chemicals present in the tea leaf extract act as reducing agents used to reduce Ag+ ions to silver atoms to form C. AgNPs in the solution. In this work, we optimized the C. AgNPs synthesis process by investigating the influence of reaction parameters such as concentration of tea leaf extract (1 ppm–50 ppm), reaction temperature (30 °C-60 °C), reaction time (5 min–100 min), and reaction rate (400 rpm–800 rpm) through absorption UV–Vis spectroscopy, TEM transmission electron microscopy, and spectroscopy X-ray. Organic compounds in tea leaf extract are detected by NMR measurement. The functional groups on the C. AgNPs are shown on the Fourier transform infrared (FTIR) spectrum. The C. AgNPs are used to degrade MB dye at 10 ppm concentration based on the photocatalytic effect using a 6500 K white light source. The C. AgNPs have also been studied for their antibacterial activity on two bacteria, Pseudomonas aeruginosa (P.A) and Staphylococcus aureus (S.A), while a positive control is Ampicillin 50 mg/ml and a negative control is H2O. The results reveal that the C. AgNPs with diameters in the range of 25 nm–55 nm degrade 10 ppm MB dye after 1 h with photodegradation efficiency up to 96 %. The antibacterial ability of C. AgNPs against both bacteria is good, even superior to that of Ampicillin. Furthermore, the particle synthesis efficiency and therefore the antibacterial activity as well as the photodegradation effect of C. AgNPs are higher than previously reported. At the same time, using green tea leaf extract to synthesize C. AgNPs creates environmentally friendly products. These useful behaviors are the potential to increase the scope and applicability of C. AgNPs, especially for biomedical applications in the near future.

Preparation of metal doped nanoparticles using flower extract of Piper betle and its anti-bacterial investigations

Preparation of Silver, Gold and Zinc oxide nanoparticles was carried out by biological reduction method using Piper betle flower (Pbf) extract which has been known for its phytochemical constituents such as carbohydrates, phenolic compounds, amino acids, proteins etc. The nano products capped with plant extract Pbf-AgNPs, Pbf-AuNPs and Pbf-ZnONPs have been characterised by UV–visible spectrophotometer (UV–vis), Fourier Transform Infrared (FT-IR), Scanning Electron Microscope (SEM), Energy Dispersive X-ray (EDX), Transmission Electron Microscope (TEM) and X-ray Diffraction (XRD) studies. The spherical and circular morphology of the green synthesised nanoparticles confirmed and supported by SEM and TEM analysis. The crystalline in nature of Pbf-AgNPs, Pbf-AuNPs and Pbf-ZnONPs were examined by an X-ray diffraction study (XRD). Optical band values were derived for nano products using UV–vis data. The anti-bacterial activities were examined on Gram-positive and Gram-negative bacteria. Among the nano products the Pbf-ZnONPs has shown potential inhibition in the range of 15 mm to 21 mm in positive bacteria and 10 mm to 14 mm in negative bacteria upon increasing concentration. Next to this Pbf-AuNPs has also shown promising results in the range of 7 mm to 12 mm and 9 mm to 20 mm in positive and negative bacteria respectively. The potentiality of nano products can be arranged Pbf-ZnONPs > Pbf-AuNPs > Pbf-AgNPs in terms of inhibition zone against microorganisms. We the pioneer to report Piper betle flower as potential capping agent for the green synthesis of Pbf-AgNPs, Pbf-AuNPs and Pbf-ZnONPs.

The effects of redox conditions on arsenic re-release from excavated marine sedimentary rock with naturally suppressed arsenic release.

Massive quantities of marine sedimentary rock are excavated from urban coastal areas. The excavated rock often releases arsenic with concurrent oxidation of framboidal pyrite, but the arsenic release is naturally suppressed with subsequent atmospheric exposure. The present study evaluated the re-release of arsenic from excavated rock in which arsenic release has been naturally suppressed by the atmospheric exposure in the presence of sulfate ions under various redox conditions using the biological reduction method. The atmospheric exposure and subsequent batch leaching test revealed that the amount of arsenic release that was naturally suppressed corresponded to 1.2% of the total arsenic content. The sequential extraction analysis also showed that the arsenic in the exposed rock was altered to insoluble phases. We observed a re-release of 6.0-18.2% of the total arsenic content under reductive conditions (< + 70mV of Eh), exceeding the amount of arsenic that was naturally suppressed, even in the presence of sulfate ions. The correlation in the amount of arsenic and iron re-released demonstrates that arsenic re-release under reductive conditions is mainly regulated by the iron dissolution up to 10mgkg-1 even in the presence of sulfate ion. Further reduction and dissolution of iron did not cause further increase in the arsenic re-release. Therefore, excavated marine sedimentary rock should be reused under redox conditions in which iron is not reduced. Otherwise, treatments such as chemical immobilization should be performed.

Nanocatalytic Activity of Silver Nanoparticles (Ag-Nps) Fabricated using Camellia sinensis (Linn) Tender Leaf Extract and their Characterization

Silver nanoparticles (Ag-NPs) were prepared by the biological reduction method. Green tea extract was taken as a reducing and stabilizing agent and silver nitrate as the metal precursor for nanoparticle synthesis. The formation of the silver nanoparticles was monitored visually and using UV-Visible absorption spectroscopy. The synthesized silver nanoparticles were characterized by UV-visible spectroscopy, FTIR, Zeta sizer, Zeta potential, and antimicrobial studies. Silver nanoparticles were also subjected to investigate nanocatalytic activity with standard pancreatic alpha-amylase and bacterial amylase enzyme by the DNS assay method. UV-Vis spectroscopy revealed the formation of silver nanoparticles by exhibiting the typical surface plasmon absorption maxima at 430 nm. Four major functional groups of bio-molecules such as phenol, carboxylic acid, protein, and alkyl group were recorded in FTIR spectra. The size of the nanoparticles ranges between 5nm and 150nm. The average size and size distribution of silver nanoparticles is 59.66nm. The zeta potential of the silver nanoparticle is negatively charged and rendered as a sharp peak at -31.7mV. Antimicrobial activity of silver nanoparticles exhibited the highest inhibition against Gram-negative bacteria than Gram-positive bacteria and yeast pathogens. Starch hydrolysis of Ag-NPs was studied with pancreatic alpha-amylase (tailor made), crude and purified bacterial amylase enzyme. The formation of reducing sugar was increased about 40-fold for a purified enzyme, 11-fold for the pancreatic enzyme, and 6-fold for crude bacterial enzyme incorporated with Ag-NPs over control. The present studies recommended that Ag-NPs have a significant role in the degradation of starch into reducing sugars by acting as a nanocatalyst.

Synthesis, characterization and antibacterial study of Ag–Au Bi-metallic nanocomposite by bioreduction using piper betle leaf extract

Biological reduction method using plant extract for the synthesis of metal and metal oxides are attracted much to the researchers due to its simplicity, which integrates the chemical technology. The special attention is given to the green synthesis of nanoparticles by easily available plants with eco-friendly system compared to other conventional methods. Silver-gold nanocomposite (Ag–Au NCp's) is synthesized by biological reduction of silver nitrate and gold chloride with biological reduction method. These metal salts are simultaneously reduced by betle leaf extract to form respective silver and gold nanocomposite. The structure and morphology of as prepared Ag–Au NCp's sample was characterized by employing powder X-ray diffraction (XRD) tool and by Scanning Electron Micrograph (SEM) tool respectively. Fourier Transform infrared (FTIR) spectral study was undertaken to know the bonding in the prepared silver sample. Energy dispersive X-ray analysis (EDX) study was undertaken to know the formation Ag–Au NCp's. Antibacterial studies are undertaken for the said nanocomposite to know its activity against bacteria.

Comparative Study on the Catalytic Degradation of Methyl Orange by Silver Nanoparticles Synthesized by Solution Combustion and Green Synthesis Method

Nanosized silver nanoparticle (Ag-NP) powder has been synthesized using solution combustion synthesis method and green biological reduction method. The percentage yield and purity inspection of the synthesized powder was performed and compared by UV–Vis, XRD and SEM. Catalytic activities of the synthesized Ag nanoparticles toward methyl orange dye degradation in the presence of NaBH4 are analyzed and have been compared in terms of percentage reduction, reaction time and apparent reaction rate. Silver nanoparticles synthesized by solution combustion synthesis method showed 94% catalytic degradation and a rate of 0.0725 min−1. The apparent kinetic rate of silver nanoparticles synthesized by solution combustion synthesis method was found to be twelve times faster than that of silver nanoparticles synthesized by green synthesis method.

An Eco-benign Synthesis of AgNps using Hydroalcoholic Extract of Brassica oleracea var. italica Plenck : Anticancer Response against Human Breast Cancer Cells MCF-7

Breast Cancer is the second foremost reason of Cancer mortality in females globally. The conventional treatments available for Breast Cancer include surgery yet they are related to serious side effects that have moved the worldwide focus towards Complementary and Alternative Medicines (CAM). One of the emerging strategies has been the use of plant extracts for synthesizing metal nanoparticles (such as gold and silver) for anticancer applications. The objective of this study is to reflect the current availed study on green synthesis of silver nanoparticles (AgNps) with its future prospects to treat Breast Cancer. The development of eco-friendly and reliable techniques for silver nanoparticles synthesis is a vital initiative in the area of nanotechnology. Brassica oleracea var. italica Plenck Leaves Extract (LE) prepared by maceration process and silver nanoparticles of LE prepared by using biological reduction method. Female rats were divided into 5 groups, Group-I served as Positive Control and received normal saline. Group-II served Negative Control (Tumor Bearing) and was treated with single dose of MCF 7. Breast Cancer Cells (1.7 mg/pellet). Group-III served Standard Control (Tumor Bearing) treated with Paclitaxel 40 mg/Kg. Group-IV served test and treated with LE 400 mg/Kg, Group-V served test and treated with LENP 400 mg/Kg respectively about 21 days and on 21th day blood samples were collected for Hematological Parameters and Feed and Water Consumption, Body Weight Determination and Organ Weight were estimated. These discoveries infer that the synthesized Silver nanoparticles utilizing green nanotechnology could be a perfect methodology to battle malignant growth and irresistible ailments. Keywords: Breast Cancer, Nanotechnology, Synthesis, , MCF-7, CAM

Biosynthesized silver nanoparticles for inhibition of antibacterial resistance and biofilm formation of methicillin-resistant coagulase negative Staphylococci

The ability of a natural stabilizing and reducing agent on the synthesis of silver nanoparticles (Ag NPs) was explored using a rapid and single-pot biological reduction method using Nocardiopsis sp. GRG1 (KT235640) biomass. The UV–visible spectral analysis of Ag NPs was found to show a maximum absorption peak located at a wavelength position of ∼422 nm for initial conformation. The major peaks in the XRD pattern were found to be in excellent agreement with the standard values of metallic Ag NPs. No other peaks of impurity phases were observed. The morphology of Ag NPs was confirmed through TEM observation, demonstrating that the particle size distribution of Ag NPs entrenched in spherical particles is in a range between 20 and 50 nm. AFM analysis further supported the nanosized morphology of the synthesized Ag NPs and allowed quantifying the Ag NPs surface roughness. The synthesized Ag NPs showed significant antibacterial and antibiofilm activity against biofilm positive methicillin-resistant coagulase negative Staphylococci (MR-CoNS), which were isolated from urinary tract infection as determined by spectroscopic methods in the concentration range of 5–60 µg/ml. The inhibition of biofilm formation with coloring stain was morphologically imaged by confocal laser scanning microscopy (CLSM). Morphological alteration of treated bacteria was observed by SEM analysis. The results clearly indicate that these biologically synthesized Ag NPs could provide a safer alternative to conventional antibiofilm agents against uropathogen of MR-CoNS.

Purple heart plant leaves extract-mediated silver nanoparticle synthesis: Optimization by Box-Behnken design

The present research work describes a novel method for green synthesis of silver nanoparticles using purple heart plant leaves extract, which is recognized as frequently found in households as an ornamental plant. The aqueous methanolic extract of purple heart plant leaves was prepared and employed in the synthesis of stable silver nanoparticles via biological reduction method. The purple heart plant leaves extract-mediated synthesized silver nanoparticles were systematically optimized using Box-Behnken design considering the effect of various independent variables (factors) like concentration of AgNO3, temperature and volume of purple heart plant leaves extract solution on the responses like particle size and polydispersity index of synthesized silver nanoparticles were optimized. Mathematical modelling was performed using quadratic polynomial model and response surface analysis was done to understand the factor-response relationship. The synthesized silver nanoparticles at optimum condition were found to be of spherical in shape under TEM with particle size of 98 nm and polydispersity index of 0.15. Optimized silver nanoparticles were further characterized through UV-VIS spectrophotometry, FTIR spectroscopy and TEM imaging studies. Also, the silver nanoparticles were evaluated for antibacterial activity on E. coli and S. aureus. In a nutshell, the studies construed successful synthesis of silver nanoparticles along with thorough understanding of the associated factors influencing their quality characteristics and significantly improved antibacterial activity as beneficial effect.

Green Synthesis, Characterization, and Thermal Study of Silver Nanoparticles by Achras sapota, Psidium guajava, and Azadirachta indica Plant Extracts

Synthetic technology of nanomaterials through plant extract is integrating due to its simplicity and also requires less apparatus. Recent development records the green synthesis of nanoparticles using the biological reduction method with the help of plant extracts. The unique process of developing an environmental friendly way for the synthesis of nanoparticles brings the significant step in the wide field of nanotechnology. Syntheses of silver nanoparticles (AgNps) are carried out by complete reduction of silver nitrate using Achras sapota, Psidium guajava, and Azadirachta indica plant extracts. The structure, morphology, and bonding nature of as-synthesized AgNps have been studied by X-ray diffraction (XRD), scanning electron micrograph (SEM), and Fourier-transform infrared (FT-IR) tools respectively. The presence of the silver metal in the sample was confirmed by EDX pattern. Thermal study of the prepared AgNps is undertaken to know its thermal behavior.

Green synthesis of pH-responsive Al2O3 nanoparticles: Application to rapid removal of nitrate ions with enhanced antibacterial activity

In this study, the green treated aluminium oxide nanoparticles (Al2O3 NPs) were synthesized through simple biological reduction method and studied the effect of pH disparity on particle size variation. Green synthesis of Al2O3 NPs from Prunus × yedoensis leaf extract (PYLE) used for removal of nitrate and antibacterial activities for the first time. The synthesized Al2O3 NPs were characterized by different standard analytical and microscopy techniques. The Al2O3 NPs formation occurred through reduction of metal ions followed by nucleation. The size of the pH = 7 Al2O3 NPs are spherical and hexagonal shape and the size ranges between 50–100 nm, although some nanoparticles are agglomerated. The band gap energy values of the pH = 7 Al2O3 NPs were 3.1 eV, which corresponds to the reflectance edge of 420 nm. The surface area of pH = 7 Al2O3 NPs determined from BET measurement was found to be 54.5014 m2/g. The green synthesized Al2O3 NPs were found to be highly efficient in removing nitrates upto 94% from aqueous solutions at pH = 7 under the influence of sunlight irradiation. This removal efficiency of the synthesized NPS is appreciable when compared with previously reported materials of same kind and hence proves its potential for its use in various ion removal from contaminant systems. The detailed in vitro antibacterial activities of the green treated Al2O3 NPs also investigated. The synthesized Al2O3 NPs at pH = 7 was found to have effective antibacterial activity against gram-positive Staphylococcus aureus (S. aureus) and gram-negative Escherichia coli (E. coli). The experimental results of the study reveals that on tuning the size of synthesized Al2O3 NPs and optimizing its pH exhibited higher catalytic activity and antibacterial activity. Hence, these green synthesized Al2O3 NPs is found to have promising applications in pollutant ion removal in aquatic systems.

Screening of larvicidal activity of nanoparticles synthesized from flower extracts of Hibiscus vitifolius

The objective of the present study was to evaluate the larvicidal activity of silver nanoparticles synthesized from aqueous extracts of Hibiscus vitifolius Linn flowers against the larvae of Aedes aegypti. Stable silver nanoparticles were synthesized by biological reduction method. The parasite larvae were exposed to varying concentrations of aqueous extract of Hibiscus vitifolius flowers and synthesized silver nanoparticles for 24 h as per World Health Organization protocols. Distilled water served as control. Percentage mortality was recorded. The synthesized nanoparticles exhibited significant larvicidal activity. This method is considered as an innovative alternative approach using green nanochemistry technique to control vector parasites and is the first report on mosquito larvicidal activity of Hibiscus vitifolius Linn flowers mediated synthesized silver nanoparticles.

Fabrication of PLA/Ag nanofibers by green synthesis method using Momordica charantia fruit extract for wound dressing applications

The paper outlines the antibacterial, in-vitro biocompatibility assay, and mechanical properties of PLA/Ag nanofibers fabricated by electrospinning technique. The colloidal nanosilver involved in the system were synthesized using biological reduction method from silver nitrate (AgNO3) and bitter gourd extract (reducing agent) in diphase medium containing PLA matrix (capping agent). The nanofibers were characterized using Scanning electron microscopy (SEM), Transmission electron microscope (TEM), Energy dispersive X-ray spectroscopy (EDS), Dynamic light scattering technique (DLS), Fourier transform-infrared spectroscopy (AT-IR), X-ray diffraction (XRD), Contact angle (WCs), Fluorescence spectroscopy and UV–vis spectroscopy (UV–vis). The capping agent (PLA) interaction with colloidal nanosilver was confirmed by the X-ray photoelectron spectroscopy (XPS). Appreciable antibacterial property was observed for PLA/Ag nanofibers on screening it against Escherichia coli and Staphylococcus aureus by agar disc diffusion method. The spherical particles with an average size of about 5–20nm were deduced by Transmission electron microscopy (TEM) analysis. The in-vitro analysis showed that the biofabricated PLA/Ag nanofiber (with Hemolytic percentage less than 5%) were also cytocompatible with fibroblast cell and does not impair cell growth. An observed WVTR of 2237.53±165g/m2.24h seem to provide an optimal moist environment locally to promote wound healing. All these results justify PLA/Ag nanofibers as a wound healer that can enhance the proliferation and function of epidermal cells and fibroblasts.

Reduction of Fe(III)EDTA by Klebsiella sp. strain FD-3 in NOx scrubber solutions

Biological reduction of Fe(III) to Fe(II) is a key step in nitrogen oxides (NOx) removal by the integrated chemical absorption–biological reduction method, which determines the concentration of Fe(II) in the scrubbing liquid. A new Fe(III)EDTA reduction strain, named as FD-3, was isolated from mixed cultures used in the integrated NOx removal process and identified as Klebsiella sp. by 16S rDNA sequence analysis. The reduction abilities of FD-3 and the influence of nitrogen-containing compounds (Fe(II)EDTA–NO, NO3- and NO2-) and sulfur-containing compounds (SO42-, SO32-) on the Fe(III)EDTA reduction were investigated. The results indicated that strain FD-3 could reduce Fe(III)EDTA efficiently. NO3-, NO2- and Fe(II)EDTA–NO inhibit the reduction of Fe(III)EDTA and could also serve as electron acceptor for strain FD-3. SO32- inhibited Fe(III)EDTA reduction while SO42- had no obviously effect on Fe(III)EDTA reduction. The relationship between cell growth and Fe(III)EDTA reduction could be described by the models based on Logistic equation.

AN EXAMINATION OF THE BIOLOGICAL REDUCTION METHOD FOR ESTIMATING ACTIVE IRON IN SOILS

SummaryAllison and Scarseth's biological reduction method was compared with three chemical methods for the removal of iron and aluminium from six Scottish surface soils. When applied to soils which had been pre‐treated with hydrogen peroxide and inoculated with Fe‐reducing bacteria the amount of Fe dissolved by this method was intermediate between Tamm's acid‐ammonium oxalate, the mildest chemical method, and Mackenzie's hydrosulphite method. When applied to untreated soils the amounts of Fe dissolved were sometimes as little as 15 per cent of that removed from peroxide‐treated soils. With the latter soils the amount of soluble Fe increased as the amount of sucrose added to the soil and as the duration or temperature of incubation increased. Al also became more soluble as sucrose increased and the pH of the fermentation decreased. The peroxide treatment rendered A1 more soluble but this could be largely counteracted by increasing the pH before fermentation. The method could be made about five times more specific for Fe than the hydrosulphite method, the most specific of the chemical methods, eight times more than Truog's nascent hydrogen sulphide method, and fourteen times more than the acid‐ammonium oxalate method.The amounts of Fe dissolved by the biological method gave little indication of phosphate sorption capacity and seemed inferior in this respect to acid‐oxalate soluble Fe. A1 dissolved by all methods, especially the chemical ones, was highly related to phosphate sorption.

A Biological Reduction Method for Removing Free Iron Oxides from Soils and Colloidal Clays1

A Biological Reduction Method for Removing Free Iron Oxides from Soils and Colloidal Clays¹