scholarly journals Synthesis of silver nanoparticles stabilized by the products of mechanically assisted hydrolysis of yeast biopolymers

2019 ◽  
Vol 81 (1) ◽  
pp. 238-246
Author(s):  
A. L. Bychkov ◽  
E. I. Ryabchikova ◽  
K. G. Korolev ◽  
V. A. Bukhtoyarov
Keyword(s):  
Silver Nanoparticles ◽  
Spherical Shape ◽  
Water Soluble ◽  
Carbonyl Groups ◽  
Silver Particles ◽  
Yeast Biomass ◽  
Reducing Ability ◽  
Hydrolysis Of ◽  
By Products

The paper presents data on the production of silver nanoparticles and their stabilization by products of the mechanoenzymatic hydrolysis of yeast biomass. The formation of silver nanoparticles by reduction using glucose without the addition of stabilizers was studied. The particles obtained have a spherical shape and a narrow size distribution. The resulting colloid is unstable and precipitates after 3-5 hours due to aggregation of unstabilized particles. Polymers contained in yeast hydrolyzates were selected taking into account silver particles nucleation mechanism. The protein molecules of these hydrolysates are involved in the formation of salts and the stabilization of the resulting dendrites. Low-molecular carbohydrates play the role of a reducing reagent. The peak on the Vis spectrum at 420 nm attributed to particles with dimensions of about 50 nm gives evidence that these dendritic formations are nanostructured. It was shown that mechanical activation together with enzymatic hydrolysis promotes an increase in the concentration of carbonyl groups of carbohydrates leading to an increase in the regenerating ability of the cell wall. The varying the processing conditions one can get silver particles in the range of 15-80 nm. Changes in silver reduction in the liquid phase in the presence of cell hydrolysis products were detected. Part of the carbohydrates as a result of hydrolysis becomes water soluble and is extracted into the solution. This leads to the fact that in the extracellular space also undergo reduction processes. In general, samples of the mechanically processed and hydrolyzed enzyme product have a greater reducing ability compared with the original cells. The quantity of spatially stabilized nanoparticles is larger than when processing native S. cerevisiae cells.

scholarly journals Hydrolysis of membrane phospholipids by phospholipases of rat liver lysosomes

1979 ◽  
Vol 182 (2) ◽  
pp. 599-606 ◽  
Author(s):  
Donald E. Richards ◽  
Robin F. Irvine ◽  
Rex M. C. Dawson
Keyword(s):  
Phospholipase C ◽  
Rat Liver ◽  
Lysosomal Enzymes ◽  
Microsomal Fraction ◽  
Water Soluble ◽  
Membrane Phospholipids ◽  
Liver Lysosomes ◽  
Rat Liver Lysosomes ◽  
Hydrolysis Of

(1) The hydrolysis of 32P- or myo-[2-3H]inositol-labelled rat liver microsomal phospholipids by rat liver lysosomal enzymes has been studied. (2) The relative rates of hydrolysis of phospholipids at pH4.5 are: sphingomyelin>phosphatidylethanolamine>phosphatidylcholine> phosphatidylinositol. (3) The predominant products of phosphatidylcholine and phosphatidylethanolamine hydrolysis are their corresponding lyso-compounds, indicating a slow rate of total deacylation. (4) Ca2+ inhibits the hydrolysis of all phospholipids, though only appreciably at high (>5mm) concentration. The hydrolysis of sphingomyelin is considerably less sensitive to Ca2+ than that of glycerophospholipids. (5) Analysis of the water-soluble products of phosphatidylinositol hydrolysis (by using myo-[3H]inositol-labelled microsomal fraction as a substrate) produced evidence that more than 95% of the product is phosphoinositol, which was derived by direct cleavage from phosphatidylinositol, rather than by hydrolysis of glycerophosphoinositol. (6) This production of phosphoinositol, allied with negligible lysophosphatidylinositol formation and a detectable accumulation of diacylglycerol, indicates that lysosomes hydrolyse membrane phosphatidylinositol almost exclusively in a phospholipase C-like manner. (7) Comparisons are drawn between the hydrolysis by lysosomal enzymes of membrane substrates and that of pure phospholipid substrates, and also the possible role of phosphatidylinositol-specific lysosomal phospholipase C in cellular phosphatidylinositol catabolism is discussed.

scholarly journals Photosynthesis of Carboxymethyl Starch-Stabilized Silver Nanoparticles and Utilization to Impart Antibacterial Finishing for Wool and Acrylic Fabrics

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
M. A. El-Sheikh ◽  
L. K. El Gabry ◽  
H. M. Ibrahim
Keyword(s):  
Silver Nanoparticles ◽  
Bacterial Growth ◽  
Irradiation Time ◽  
Synthesis Method ◽  
Antibacterial Properties ◽  
Spherical Shape ◽  
Inhibition Zone ◽  
Water Soluble ◽  
Carboxymethyl Starch ◽  
Antibacterial Performance

The water soluble photoinitiator (PI) 4-(trimethyl ammonium methyl) benzophenone chloride/UV system is used in the synthesis of silver nanoparticles (AgNPs). Green synthesis method involved using PI/UV system, carboxymethyl starch (CMS), silver nitrate, and water. AgNPs obtained had a spherical shape morphology and a size of 1–7 nm. To impart antibacterial properties, wool and acrylic fabrics were treated with AgNPs obtained. The PI/UV system was further utilized to fix AgNPs onto wool and acrylic fabrics by photocrosslinking to impart durable antibacterial properties. The effect of irradiation time on the antibacterial performance before and after repeated washing cycles was studied. S. aureus (as G +ve) and E. coli (as G −ve) were used to estimate the antibacterial performance of the finished fabrics. The antibacterial performance was directly proportional to the irradiation time but inversely proportional to the number of washing cycles. However, after the 15th washing cycle, samples still have bacteriostatic effect; that is, although they show zero inhibition zone, they cannot be attacked by the bacterial growth and do not inhibit the bacterial growth. AgNPs finished wool fabrics showed more antibacterial activity than those of AgNPs finished acrylic fabrics.

scholarly journals Role of Salvia officinal's Silver Nanoparticles in Attenuating Renal Damage in Rats Exposed to Methotrexate(Part I)

2019 ◽  
Vol 42 (2) ◽  
pp. 7-20
Author(s):  
Khalisa Khadhim Khudiar
Keyword(s):  
Silver Nanoparticles ◽  
Uric Acid ◽  
Serum Creatinine ◽  
Silver Nitrate ◽  
Renal Damage ◽  
Protective Role ◽  
Alcoholic Extract ◽  
Silver Particles ◽  
Nano Silver

The aim of the present study was to investigate the protective role of Salvia officinal's silver nanoparticles as antioxidant on nephrotic damage induced by methotrexate in adult rats. Green silver nanoparticles were synthesized using alcoholic extract of salvia officinal's leaves, and were characterized by UV-spectrophotometry and scanning electron microscope. The mixing of the plant extract of Salvia. officinal's with silver nitrate solution (1mM), lead to changing of the reaction mixture color to yellowish within one hour and to dark brown after 8 hours, indicating the generation of Salvia officinal's silver nanoparticles , due to the reduction of silver metal ions silver (Ag+) into Nano silver particles  via the active compounds present in the S. officinal's plant extracts. Changing in color after the reduction of Ag+ to Salvia officinal's silver nanoparticles. The reduction rate and formation of nanoparticles can be increased further by increase in incubation time. Silver nitrate conversion to Nano silver particles  was found to be successful as suggested by the change in color of the solution to brown. For studying the protective role of Salvia officinal's silver nanoparticles , twenty eight adult  Wister albino rats were randomly assigned  and divided in to four groups as follows T1, T2, T3, and  T4, They were treated intramuscularly (twice per week) for 45 days as follows; T1:animals in this group, were given Salvia officinal's (150mg /Kg/.B.W), T2: animals in  this groups were given Salvia officinal's Silver nanoparticles (150mg/Kg B.W.); T3:animals  of this groups were given both Methotrexate (0.25mg/kg/ B.W.) and Salvia officinal's silver nanoparticles (150mg/Kg/B.W); T4: animals in this groups were given methotrexate (0.25mg/Kg B.W.) for 45 days . The animals of all groups were considered as control group at day zero and injected only doubled distilled water Intramuscala.  Fasting blood samples were collected at 0, 15, 30 and 45 days of experimental periods from anesthetized rats using retro-orbital sinus technique and cardiac puncture technique, then sera was isolated for measuring: malondialdehyde, glutathione  in serum, creatinine, and blood urea nitrogen  and uric acid concentrations. The results showed that animals received methotrexate (group T4) caused a case of oxidative stress manifested by significant decrease grower in , elevation in malondialdehyde  concentrations, renal dysfunction as documented by significant elevation in serum creatinine, urea and uric acid concentrations. On the other hand, the protective role of salvia officinal's  and Salvia officinal's silver nanoparticles given concurrently with methotrexate was clarified in groups T2and T3 ,where there was alleviation of renal damage through correction of the previous mentioned parameters and  correction of antioxidant status. In conclusion, the current study documented the antioxidant activity and reno protective effects of Salvia officinal's silver nanoparticles  against damaging effects of methotrexate in rats. 

Nanostructured DLC-Ag Composites for Biomedical Applications

2002 ◽  
Vol 750 ◽  
Author(s):  
R. J. Narayan ◽  
H. Wang ◽  
A. Tiwari
Keyword(s):  
Silver Nanoparticles ◽  
Biomedical Applications ◽  
Silver Particles ◽  
Adhesion Properties ◽  
Carbon Coatings ◽  
Bonding Ratio ◽  
Diamondlike Carbon ◽  
Z Contrast ◽  
Electron Energy Loss

ABSTRACTWe have synthesized novel diamondlike carbon coatings with silver nanoparticles embedded into the DLC film. The size of silver nanoparticles that are confined into layered structures has been varied from 5 nm to 50 nm using an ingenious pulsed laser deposition technique. The size of nanoparticles was found to be remarkably uniform within 15%. We have characterized these samples using high-resolution cross-section TEM and STEM-Z contrast techniques, electron energy loss spectroscopy (EELS), Raman, nanohardness, adhesion, and biocompatibility measurements. In the STEM-Z, where the contrast is proportional to atomic number2, we have obtained the details of the atomic structure of silver particles. We have correlated the microstructure with hardness and adhesion properties. The EELS was used in conjunction with STEM-Z to obtain sp3/sp2 bonding ratio. This ratio was compared with Raman result to provide an average bulk value. The role of silver nanoparticles is surmised to provide a reservoir of electrons for antimicrobial activity on the surface, as revealed by our biocompatibility tests.

Application of Plakett-Burman Screening Design in Optimization of Process Parameters for Formulation of Canaglifozin Nanosuspension

2020 ◽  
Vol 13 (6) ◽  
pp. 5208-5216
Author(s):  
Nisha Patel ◽  
Hitesh A Patel
Keyword(s):  
Particle Size ◽  
Particle Diameter ◽  
Spherical Shape ◽  
Water Soluble ◽  
Pareto Chart ◽  
Independent Variables ◽  
Mean Particle Size ◽  
Screening Design ◽  
Stirring Time ◽  
Response Variables

In this study, we sought to improve the dissolution characteristics of a poorly water-soluble BCS class IV drug canaglifozin, by preparing nanosuspension using media milling method. A Plackett–Burman screening design was employed to screen the significant formulation and process variables. A total of 12 experiment were generated by design expert trial version 12 for screening 5 independent variables namely the amount of stabilizer in mg (X1), stirring time in hr (X2), amt of Zirconium oxide beads in gm (X3), amount of drug in mg (X4) and stirring speed in rpm (X5) while mean particle size in nm (Y1) and drug release in 10 min. were selected as the response variables. All the regression models yielded a good fit with high determination coefficient and F value. The Pareto chart depicted that all the independent variables except the amount of canaglifozin had a significant effect (p<0.001) on the response variables. The mathematical model for mean particle size generated from the regression analysis was given by mean particle size = +636.48889 -1.28267 amt of stabilizer(X1) -4.20417 stirring time (X2) -7.58333 amt of ZrO2 beads(X3) -0.105556 amt of drug(X4) -0.245167 stirring speed(X5) (R2=0.9484, F ratio=22.07, p<0.001). Prepared canaglifozin nanosuspension exemplified a significant improvement (p<0.05) in the release as compared to pure canaglifozin and marketed tablet with the optimum formulation releasing almost 80% drug within first 10min. Optimized nanosuspension showed spherical shape with surface oriented stabilizer molecules and a mean particle diameter of 120.5 nm. There was no change in crystalline nature after formulation and it was found to be chemically stable with high drug content.

Synthesis and Characterization of Florfenicol-silver Nanocomposite and its Antibacterial Activity against some Gram Positive and Gram-negative Bacteria

2020 ◽  
Keyword(s):  
Silver Nanoparticles ◽  
Electron Microscope ◽  
Zeta Potential ◽  
Surface Area ◽  
Spherical Shape ◽  
Bet Surface Area ◽  
Sonochemical Method ◽  
Raman Spectrometry ◽  
Silver Nanocomposite ◽  
Morphology Characterization

In this paper, easy, rapid and cheap synthetic method was described for florfenicol-silver nanocomposite by sonochemical method. Florfenicol-silver nanocomposite was characterized based on three classes namely index, identification and morphology class. Index characterization was carried out by zeta sizing, BET surface area and zeta potential. Identification characterization was performed using X-ray diffraction (XRD) and Raman spectrometry. Morphology characterization was done utilizing transmission electron microscope (TEM), scanning electron microscope (SEM) and atomic force microscope (AFM). Characterization results showed zeta sizing of florfenicol was 30.44nm, while florfenicol-silver nanocomposite was 33.5 nm with zeta potential -14.1 and -18, respectively. BET surface area was found to be 13.3, 73.2 and 103.69 m2/g for florfenicol, silver nanoparticles and florfenicol-silver nanocomposite respectively. XRD and Raman charts confirmed the formation of florfenicol-silver nanocomposite without any contamination. TEM, SEM and AFM spectral data illustrated spherical to sub spherical shape of silver nanoparticles on cubic to sheet shape of florfenicol with size less than 50 nm. Antimicrobial activity was screened where the average zone of inhibitions caused by the prepared nanocomposite were 28.3 mm, 24 mm, 27.3 mm and 24 mm compared to 17.7 mm, 16 mm, 18.7 mm and 13.3 mm of the native drug and 13 mm, 10 mm, 14.3 mm and 15 mm of the used positive reference standards against E. coli, Salmonella typhymurium, Staphylococcus aureus and Staph.aureus MRSA respectively.

Green and Simple Synthesis of Silver Nanoparticles by Aqueous Extract of Perovskia abrotanoides: Characterization, Optimization and Antimicrobial Activity

2020 ◽  
Vol 21 (11) ◽  
pp. 1129-1137 ◽  
Author(s):  
Somayeh Mirsadeghi ◽  
Masoumeh F. Koudehi ◽  
Hamid R. Rajabi ◽  
Seied M. Pourmortazavi
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Minimum Inhibitory Concentration ◽  
Plant Extract ◽  
Inhibitory Concentration ◽  
Minimum Bactericidal Concentration ◽  
Extraction Temperature ◽  
Silver Particles ◽  
Silver Nps ◽  
Perovskia Abrotanoides

Background: Herein, we report the biosynthesis procedure to prepare silver nanoparticles as reduction and capping agents with the aqueous plant extract of Perovskia abrotanoides. Methods: The therapeutic application of silver nanoparticles entirely depends on the size and shape of the nanoparticles therefore, their control during the synthesis procedure is so important. The effects of synthesis factors, for example, silver ion concentration, the mass of plant extract, reaction time and extraction temperature, on the size of silver particles were considered and optimized. Several analytical methods were used for the characterization of silver NPs including FT-IR and UV–Vis spectrophotometer, XRD and SEM. Results: The results showed that the mean size of the silver particles was about 51 nm. Moreover, the antibacterial properties of biosynthesized silver NPs were investigated by the minimum inhibitory concentration, minimum bactericidal concentration, and Well-diffusion tests. The minimum inhibitory concentration/ minimum bactericidal concentration values of silver NPs and aqueous plant extract versus Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) and Gram-negative bacteria (E. coli) were 3.03/0.00, 1.20/0.01, 3.06/0.00, 0.98/1.04, 1.00/0.05 and 1.30/0.03 (mg/mL), respectively. Conclusion: The antimicrobial activity study displayed that the synthesized silver nanoparticles by plant extract have better antimicrobial properties compared to aqueous plant extract of Perovskia abrotanoides.

Understanding the Role of Chlorine and Ozone to Control Postharvest Diseases in Fruit and Vegetables: A Review

2020 ◽  
Vol 16 (4) ◽  
pp. 455-461
Author(s):  
Gabriela M. Baia ◽  
Otniel Freitas-Silva ◽  
Murillo F. Junior
Keyword(s):  
Chlorine Dioxide ◽  
Broad Spectrum ◽  
Fruits And Vegetables ◽  
Low Cost ◽  
Residual Effects ◽  
Pathogenic Microorganisms ◽  
Postharvest Diseases ◽  
Post Harvest ◽  
By Products

Fruits and vegetables are foods that come into contact with various types of microorganisms from planting to their consumption. A lack or poor sanitation of these products after harvest can cause high losses due to deterioration and/ or pathogenic microorganisms. There are practically no post-harvest fungicides or bactericides with a broad spectrum of action that have no toxic residual effects and are safe. However, to minimize such problems, the use of sanitizers is an efficient device against these microorganisms. Chlorine is the most prevalent sanitizing agent because of its broad spectrum, low cost and well-established practices. However, the inevitable formation of disinfection by-products, such as trihalomethanes (THMs) and haloacetic acids (HAAs), is considered one of the main threats to food safety. Alternative sanitizers, such as chlorine dioxide (ClO2) and ozone, are becoming popular as a substitute for traditional post-harvest treatments. Thus, this review addresses the use of chlorine, chlorine dioxide and ozone emphasizing aspects, such as usage, safe application, spectrum of action and legislation. In order to ensure the quality and safety of final products, the adoption of well-prepared sanitation and sanitation programs for post-harvest fruits and vegetables is essential.

Green synthesis of silver nanoparticles using sustainable resources and their use as antibacterial agents: A review

2020 ◽  
Vol 13 ◽  
Author(s):  
Kumari Jyoti ◽  
Punyasloka Pattnaik ◽  
Tej Singh
Keyword(s):  
Silver Nanoparticles ◽  
Plant Extracts ◽  
Metallic Nanoparticles ◽  
Cost Effective ◽  
Biological Properties ◽  
Metal Species ◽  
Sustainable Resources ◽  
Research Areas ◽  
Low Toxicity

Background:: Synthesis of metallic nanoparticles has attracted extensive vitality in numerous research areas such as drug delivery, biomedicine, catalysis etc. where continuous efforts are being made by scientists and engineers to investigate new dimensions for both technological and industrial advancements. Amongst numerous metallic nanoparticles, silver nanoparticle (AgNPs) is a novel metal species with low toxicity, higher stability and significant chemical, physical and biological properties. Methods:: In this, various methods for the fabrication of AgNPs are summarized. Importantly, we concentrated on the role of reducing agents of different plants parts, various working conditions such as AgNO3 concentration; ratio of AgNO3/extract; incubation time; centrifugal conditions, size and shapes. Results:: This study suggested that eco-friendly and non toxic biomolecules present in the extracts (e.g. leaf, stem and root) of plants are used as reducing and capping agents for silver nanoparticles fabrication. This method of fabrication of silver nanoparticles using plants extracts is comparatively cost-effective and simple. A silver salt is simply reduced by biomolecules present in the extracts of these plants. In this review, we have emphasized the synthesis and antibacterial potential of silver nanoparticles using various plant extracts. Conclusion:: Fabrication of silver nanoparticles using plant extracts have advantage over the other physical methods, as it is safe, eco-friendly and simple to use. Plants have huge potential for the fabrication of silver nanoparticles of wide potential of applications with desired shape and size.

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