scholarly journals A GREEN AND SIMPLE SYNTHESIS OF CHITOSAN/Ag NANOCOMPOSITES AND STUDY FOR THEIR ANTIBACTERIAL ACTIVITY ON STAPHYLOCOCCUS AUREUS AND ESCHERICHIA COLI

2018 ◽  
Vol 56 (2A) ◽  
pp. 89-98
Author(s):  
Tran Thi Bich Quyen

A green and simple approach has been successfully developed to synthesize chitosan/Ag nanocomposites using kumquat extract as a biological reducing agent. It indicates to be an eco-friendly and green method for the synthesis providing a cost effective and an efficient route for the chitosan/Ag nanocomposites’ synthesis. The prepared chitosan/Ag nanocomposites have been characterized by UV-vis, TEM, FTIR, and XRD. Result showed those chitosan/Ag nanocomposites have been obtained with average particle size ~15-25 nm. Moreover, the synthesized chitosan/Ag nanocomposites also showed their efficient antimicrobial activity against S. aureus and E. coli. The chitosan/Ag nanocomposite was found to have significantly higher antimicrobial activity than its components at their respective concentrations. The presence of a small percentage (2.5 %, w/w) of metal nanoparticles in the nanocomposite was enough to significantly enhance inactivation of S. aureus and E. coli as compared with unaltered chitosan. Thus, this eco-friendly method could be a competitive alternative to the conventional physical/chemical methods used for the synthesis of chitosan/Ag nanocomposites. Since, it has a potential to use in biomedical and cosmetic applications. 

2018 ◽  
Vol 8 (5) ◽  
pp. 178-183
Author(s):  
Manish Kumar ◽  
Hemant K. Sharma

The objective of this study is to prepare nanogels were prepared via charged gellan gum. It was prepared by in situ cross linking reaction between two oppositely charged materials by green method without use of chemical cross linking agents. The prepared nanogels were characterized by Dynamic light scattering, scanning electron microscopy, differential scanning calorimetry and X- Ray diffractometry. The prepared formulation had average particle size of 226 nm with polydispersity index of 0.3. The doxorubicin loaded nanogel demonstrated sustained release for 20 h. The prepared nanogels were hemocompatible and cyctocompatible as revealed by hemocompatibility and MTT assay respectively. All results confirmed that these nanogels can be used for cancer treatment. Keywords: Nanogel, Chitosan, Gellan gum, Doxorubicin, Cancer.


2002 ◽  
Vol 720 ◽  
Author(s):  
N N Ghosh

AbstractIn the present investigation, an attempt has been made to establish a new chemical route for synthesis of the nanostructured mixed oxide ferrite powders. By using this chemical method a variety of ferrite powders having spinel structure and doped with Co, Ni, Mn, Zn etc has been prepared. In this method nitrate salts of the different metals were used as starting materials. The aqueous solutions of the metal nitrates were mixed according to the molar ration of the compositions. Then the mixtures were mixed with an aqueous solution of water soluble polymer (polyvinyl alcohol). This mixture after drying yield fluffy brown powders. These powders were then calcined at different temperatures ranging from 400 °C to 700 °C. Nanostructured powders were obtained from the thermal decomposition of the brown powders. The powders, prepared by calcinations at different temperatures, were characterized by using X-Ray diffraction analysis, IR spectroscopy, TGA/DTA, and TEM. It was observed that the average particle size of the powders are in nanometer scale with a narrow size distribution. The average particle size of the powders was increased with the increase of calcinations temperature.This chemical method has proved to provide a convenient process for the preparation of nanostructured ceramic powders at comparatively low temperatures and offers the potential of being a simple and cost-effective route.


2019 ◽  
Vol 99 (4) ◽  
pp. 713-723 ◽  
Author(s):  
Gabriela Tasso Pinheiro Machado ◽  
Maria Beatriz Veleirinho ◽  
Letícia Mazzarino ◽  
Luiz Carlos Pinheiro Machado Filho ◽  
Marcelo Maraschin ◽  
...  

This study describes the development of propolis nanoparticles (PNP) to treat bovine mastitis. Three PNP prepared with varying concentrations of propolis (5% and 7%, w/v) and the surfactants [poloxamer (1%, 3%, and 4%, w/v) and soy lecithin (0.25%, 0.7%, and 1%, w/v)]. PNP were characterized according to their size, polydispersity, zeta potential, pH, morphology, and physical stability. PNP were evaluated for their in vitro antimicrobial and cytotoxic effects. PNP obtained were spherical with a monodisperse distribution (polydispersity index < 0.2) and an average particle size between 181 and 201 nm. Stability studies showed that PNP were stable over 150 d. The encapsulation efficiency of total phenolic content varied between 73% and 91%. The chromatographic profile of phenolic compounds from PNP showed selective encapsulation efficiency according to the polarity of compounds. All PNP showed antimicrobial activity against Staphylococcus aureus with a minimum inhibitory concentration ranging from 156 to 310 μg mL−1. The IC50 (the concentration responsible for reduction of cellular viability by half) for epithelial cells of bovine mammary gland (MAC-T, mammary alveolar cell-T) varied from 122.2 to 268.4 μg mL−1. Results showed that PNP represent a promising nanocarrier for high concentrations of propolis extract in a stable aqueous medium, while, at the same time, presenting antimicrobial activity accompanied by moderate cytotoxicity to the MAC-T cells.


2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Nguyen Lam Uyen Vo ◽  
Thi Thuy Van Nguyen ◽  
Tri Nguyen ◽  
Phung Anh Nguyen ◽  
Van Minh Nguyen ◽  
...  

In this study, CuO-ZnO composite was synthesized via the sol-gel method using oxalic acid to form the medium complex and its applications in antibacterial have been conducted with B. cereus, E. coli, S. aureus, Salmonella, and P. aeruginosa. Then, nanopowder of CuO-ZnO was coated on shoe insoles and their antibacterial effect with S. aureus was tested. The nanocomposite products were characterized by XRD, XPS, SEM, TEM, and UV-Vis. The results showed that the CuO-ZnO composite has the average particle size in a range of 20-50 nm, the point of zero charge of 7.8, and the bandgap of 1.7 eV. XPS result shows the composite structure with Cu2+ in the product. The minimum inhibitory concentration (MIC) of CuO-ZnO nanocomposite was 0.313 mg·mL-1 for S. aureus and Samonella, 0.625 mg·mL-1 for E. coli, and 5 mg·mL-1 for B. cereus and P. aeruginosa. The shoe insoles coated with 0.35 wt.% of CuO-ZnO nanocomposite also had high antibacterial activity against S. aureus, and this antibacterial nanocomposite was implanted durably on the surface of the shoe insoles.


2020 ◽  
Vol EJMM29 (4) ◽  
pp. 143-149
Author(s):  
Ahmed M. El-Khawaga ◽  
Ayman A. Farrag ◽  
Ahmed I. El-Batal ◽  
Mohamed A. Elsayed

Background: Antimicrobial resistance (AMR) has emerged as one of the principal public health problems of the 21st century that threatens the effective prevention and treatment of an ever-increasing range of infections caused by bacteria no longer susceptible to the common medicines used to treat them. Objectives: To development of Fe3O4 NPs with specific sizes and shapes Potential as a new antibacterial agent. Methodology: In this study magnetite nanoparticles (Fe3O4 NPs) were synthesized through an aqueous co-precipitation method and functionalized with citric acid for outstanding their antimicrobial potential. Fe3O4 NPs were characterized by XRD, TEM, SEM, EDX and FTIR to analyze crystallinity, average particle size, morphology and functional groups, respectively. Antimicrobial activity was investigated against pathogenic bacteria as zone of inhibition (ZOI) and minimum inhibitory concentration (MIC). Results: Antimicrobial results showed that CA- Fe3O4 NPs owns maximum activity against Staphylococcus aureus and E. coli by 18.0 and 15.0mm ZOI, respectively. Conclusion: It should be noted that (CA-Fe3O4) NPs are also active upon Gram-positive than Gram- negative bacteria. The synthesized (CA-Fe3O4) NPs are promising for potential applications as antimicrobial agent and in drug delivery fields.


2018 ◽  
Vol 50 (1) ◽  
pp. 133-138 ◽  
Author(s):  
Lizina Khatua ◽  
Rudrashish Panda ◽  
Avanendra Singh ◽  
Arpan Nayak ◽  
Pravakar Satapathy ◽  
...  

In this work, the ZnO-TiO2 mixed phase nanoparticles were prepared by solid state reaction method by using ZnO and TiO2 powder as precursors. The X-ray diffraction pattern shows a dominant phase of Zinc Orthotitanate (Zn2TiO4). The average particle size (58?18 nm) calculated by the analysing FESEM data closely matches with the particle size calculated by Scherrer?s equation. The calculated average particle size is significantly smaller than the previously published results of nanoparticles, prepared by same method. In the Brunauer-Emmett-Teller (BET) study the specific surface area of the nanoparticles was found as 8.78 m2/g which is similar to the surface area reported in this material prepared by mechanochemical method. The method which we report is simpler and cost effective unlike the previous reported.


2021 ◽  
Vol 18 (1) ◽  
pp. 66-74
Author(s):  
Umesh Jagannath Tupe ◽  
Arun Vitthal Patil ◽  
Madhukar Sarvottam Zambare ◽  
Prashant Bhimrao Koli

The present research deals with the fabrication of stannous oxide nanoparticles by conventional and cost effective co precipitation method. The thick film sensors of SnO2 nanoparticles were prepared by standard screen-printing technique by photolithography. The prepared SnO2 material was characterized by several techniques to confirm the structural properties. Initially, the prepared nanoparticles of SnO2 were investigated by x-ray diffraction technique to confirm the synthesis of prepared material within nanoscale. From XRD data the average particle size of prepared thick films was found to be 21.87 nm calculated using Debye-Scherer formula. The material was further characterized by using scanning electron microscopy (SEM) to investigate the structural and surface characteristic of SnO2. SEM data clearly indicates the heterogeneous surface, and some voids present over the surface of SnO2 nanoparticles. The Fourier transfer infra red technique was employed to investigate the metal oxygen frequency of SnO2 material. The prepared sensor was exclusively utilized to sense the hydrogen sulfide gas vapors at various concentrations. The prepared sensor was found to be highly sensitive to H2S vapors nearly 63.8% sensitivity was recorded. The response and recovery study shows the response time of 9 seconds and recovery time of 19 seconds for hydrogen sulfide gas vapors. The SnO2 sensor was further utilized for recycling performance to get the firm results of sensitivity in four turns with period of 15 days.


2021 ◽  
Vol 12 (2) ◽  
pp. 104-111
Author(s):  
O. G. Sirenko ◽  
◽  
O. M. Lisova ◽  
S. M. Makhno ◽  
G. M. Gunya ◽  
...  

Polymeric construction materials based on epoxy resin, carbon fillers, such as graphene nanoplates (GNP), carbon nanotubes (CNT) and fillers of inorganic nature – perlite, vermiculite, sand with improved electrophysical characteristics have been developed. The electrophysical propertieгs of composites obtained in various ways which differ according to the principle of injecting components have been investigated. GNP were obtained in two ways. Size distribution of GNP obtained by electrochemical method is 50 to 150 nm. The average particle size is up to 100 nm. It occurs that these particles tend to aggregate as it is shown by the method of dynamic light scattering. The GNP obtained by dispersing thermally expanded graphite in water in a rotary homogenizer have a particle size distribution of 400 to 800 nm if very small particles and large aggregates are absent. The second method of obtaining GNP is less energy consuming and requires fewer manufacturing cycles, so it is more cost-effective. Obtaining composites using aqueous suspensions of GNP is environmentally friendly. Due to the hydrophobic properties of its surface the electrical conductivity of the system which uses vermiculite is higher than one of that which uses perlite for composites with CNT and GNP. It has been found that the difference of electrophysical characteristics between two systems which contain the same amount of carbon filler is caused by the nature of the surface of dielectric components – sand. By changing the content of dielectric ingredients can expand the functionality of composites if use them for shielding from electromagnetic fields.


2021 ◽  
Vol 37 (2) ◽  
pp. 405-412
Author(s):  
Mohamed Habib Oueslati ◽  
Lotfi Ben Tahar ◽  
A. Khuzaim Alzahrani ◽  
Jamith Basha ◽  
Omar H. Abd Elkader

The present work reports a green biosynthesis of gold nano particles (EO-AuNPs) using an essential oil (EO) as a reducing agent of the Au(III) in HAuCl4. The EO was extracted by hydro-distillation from Diplotaxis acris flowers. A total of 16 compounds were detected from the EO oil by using GC–MS and 5-methylsulfanylpentanenitrile was identified as the major component (73.60 %). The biosynthesized EO-AuNPs were characterized performing UV–Vis, IR,XRD and TEM analyses.The UV-Vis revealed the typical features of surface plasmon resonance (SPR) of AuNPs at ~526 nm. The FT-IR spectrum of the biosynthesized nano particles exhibited the features of the nitrile (-C≡N) functional group indicating that the -C≡N-bearing EO components are likely acting as reducing and stabilizing agents for the formation of EO-AuNPs. The plausible scheme of EO-AuNPsformation was proposed.The TEM analysis showed that the EO- AuNPs were almost spherical in shape with an average particle size of 12.7 nm. In addition, the antimicrobial activity was carried out by diffusion of agar wells method. The results proved that the EO-AuNPs displayed a potential antimicrobial against gram negative strains, with a maximum zone of inhibition of 16 mm for E. coli at a concentration of 100 µg / ml.


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