scholarly journals Investigation of Nanoparticle Metallic Core Antibacterial Activity: Gold and Silver Nanoparticles against Escherichia coli and Staphylococcus aureus

2021 ◽  
Vol 22 (4) ◽  
pp. 1905
Author(s):  
Jimmy Gouyau ◽  
Raphaël E. Duval ◽  
Ariane Boudier ◽  
Emmanuel Lamouroux

Multidrug-resistant (MDR) bacteria constitute a global health issue. Over the past ten years, interest in nanoparticles, particularly metallic ones, has grown as potential antibacterial candidates. However, as there is no consensus about the procedure to characterize the metallic nanoparticles (MNPs; i.e., metallic aggregates) and evaluate their antibacterial activity, it is impossible to conclude about their real effectiveness as a new antibacterial agent. To give part of the answer to this question, 12 nm gold and silver nanoparticles have been prepared by a chemical approach. After their characterization by transmission electronic microscopy (TEM), Dynamic Light Scattering (DLS), and UltraViolet-visible (UV-vis) spectroscopy, their surface accessibility was tested through the catalytic reduction of the 4-nitrophenol, and their stability in bacterial culture medium was studied. Finally, the antibacterial activities of 12 nm gold and silver nanoparticles facing Staphylococcus aureus and Escherichia coli have been evaluated using the broth microdilution method. The results show that gold nanoparticles have a weak antibacterial activity (i.e., slight inhibition of bacterial growth) against the two bacteria tested. In contrast, silver nanoparticles have no activity on S. aureus but demonstrate a high antibacterial activity against Escherichia coli, with a minimum inhibitory concentration of 128 µmol/L. This high antibacterial activity is also maintained against two MDR-E. coli strains.

2019 ◽  
Vol 10 (4) ◽  
pp. 3636-3643
Author(s):  
Hor Jia Wei ◽  
Mohd. Syafiq Awang ◽  
Nor Dyana ◽  
Daruliza Kernain ◽  
Yazmin Bustami

Silver nanoparticles (AgNPs) has long known for its inhibitory and bactericidal effects. However, due to its’ attractive antibacterial property, on-going research with various synthesis strategies actively been conducted. In this study, the synthesis of AgNPs was reported, using a simple chemical reduction method with citrate as the reducing agent TEM was used to characterize the obtained AgNPs. Then, Staphylococcus aureus and Escherichia coli were used to identify the antibacterial activity of AgNPs. The inhibition effects of AgNPs against these two bacteria were observed via disc diffusion, and MIC assays and the effects of AgNPs mode of action on both bacteria were further observed under TEM. The formation of AgNPs at ̴ 400 nm, which is the surface plasmon resonance peak was observed using Uv-Vis spectroscopy. The size of AgNPs mostly in the range of 1-10 nm and their morphology appeared to be spherical. Based on the MIC assay, Escherichia coli exhibit low MIC value with 0.049 mg/ml as compared to Staphylococcus aureus with0.391 mg/ml MIC value; correspond to the effective antibacterial activity by the citrate-reduced AgNPs. Further observation on the bacterial surface structure can be seen with cross-sectional TEM image, and it provides an insight into the AgNPs mechanistic aspects of AgNPs against Staphylococcus aureus and Escherichia coli. Silver nanoparticles have been successfully synthesised using the citrate reduction method. Results obtained in this study thus elucidating promising findings to employed AgNPs as an antibacterial agent, and this composition needs to be further study and develop into an antibacterial agent.


2019 ◽  
Vol 9 (04) ◽  
pp. 678-681
Author(s):  
Ashraf S Hassan ◽  
Khawlah J Khalaf ◽  
Hamzia A Ajah

The present study demonstrates the effect of storage period on silver nanoparticles (AgNPs), which synthesized by Pseudomonas aeruginosa and their antibacterial activity. The result shows that the size of (AgNPs) which synthesis by Pseudomonas aeruginosa was 93.55nm after 4-72hour, and when storage about 2 years, we found that the size of AgNPs was stable and reduced to 69.0nm. Antibacterial activity against pathogenic microbes: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Serratia sp,Streptococcus sp , Klebsiella sp, Candida albicans was performed before and after storage and found that AgNPs have activity against this microbes.


Chemotherapy ◽  
2021 ◽  
Author(s):  
Lluvia Itzel López-López ◽  
Ernesto Rivera-Ávalos ◽  
Cecilia Villarreal-Reyes ◽  
Fidel Martínez-Gutiérrez ◽  
Denisse de Loera

Background: The synthesis and biological evaluation of 1,4-naphthoquinone derivatives are of great interest since these compounds exhibit strong antibacterial, antifungal, antimalarial, and anticancer activities. The electronic properties of naphthoquinones are usually modulated by attaching functional groups containing nitrogen, oxygen and sulfur atoms, which tune their biological potency and selectivity. Methods: A series of 13 amino acid 1,4-naphthoquinone derivatives were synthesized under assisted microwave and ultrasound conditions. The antibacterial activity compounds was tested against American type Culture Collection (ATCC): Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis, as well two multidrug resistant pathogens: Escherichia coli and Staphylococcus aureus from clinical isolated. Minimal inhibitory concentration (MIC) was determined using the broth microdilution method. Results: MIC of derivatives 4–11, 14 and 16 showed antimicrobial activity against gram-positive and gram-negative bacteria. Antimicrobial activities of the compounds 4–8 and 14 were ≤MIC 24.7 μg∙mL-1 against all the reference strain, even more the compound 6 showed the most potent activity with a MIC of 3.9 μg∙mL-1 on S. aureus. On the clinical isolated the compounds 7, 8 and 14 showed a MIC of 49.7 and 24.7 μg∙mL-1 against S. aureus y E. coli respectively. About ADME properties and Osiris analysis, the compounds 4-16 presented high gastrointestinal absorption and good characteristics for oral bioavailability and the compound 14 was the less toxic. Conclusion: amino acid 1,4-naphthoquinone derivatives showed good in vitro antibacterial activity against clinical strains, and modifications on C-3 with cloride atom enhanced the efficiency against same pathogens.


2021 ◽  
Vol 21 (10) ◽  
pp. 5120-5130
Author(s):  
Hui Long ◽  
Wei-Cong Kuang ◽  
Shi-Liang Wang ◽  
Jing-Xian Zhang ◽  
Lang-Huan Huang ◽  
...  

Poly(cyclotriphosphazene-co-4,4’-diaminodiphenyl ether) (PPO) microspheres were prepared via a precipitation polymerization method, using hexachlorocyclotriphosphazene (HCCP) and 4,4’-diaminodiphenyl ether (ODA) as monomers. Silver-loaded PPO (PPOA) microspheres were generated by the in situ loading of silver nanoparticles onto the surface by Ag+ reduction. Our results showed that PPOA microspheres were successfully prepared with a relatively uniform distribution of silver nanoparticles on microsphere surfaces. PPOA microspheres had good thermal stability and excellent antibacterial activity towards Escherichia coli and Staphylococcus aureus. Furthermore, PPOA microspheres exhibited lower cytotoxicity when compared to citrate-modified silver nanoparticles (c-Ag), and good sustained release properties. Our data indicated that polyphosphazene-based PPOA microspheres are promising antibacterial agents in the biological materials field.


2018 ◽  
Vol 7 (3) ◽  
pp. 1570
Author(s):  
Nguyen Phung Anh ◽  
Truong Thi Ai Mi ◽  
Duong Huynh Thanh Linh ◽  
Nguyen Thi Thuy Van ◽  
Hoang Tien Cuong ◽  
...  

A rapid way of synthesizing silver nanoparticles (AgNPs) by treating Ag+ ions with a green Fortunella Japonica (F.J.) extract as a combined reducing and stabilizing agent was investigated. The reaction solutions were monitored using UV-Vis spectroscopy, the size and shape of crystals were determined by scanning electron microscopy and transmission electron microscopy, the crystalline phases of AgNPs were presented by X–ray diffraction, and the relation of nanoparticles with Fortunella Japonica extract was confirmed using fourier transform infrared spectroscopy. The results indicated that no formation of AgNPs had taken place in the dark during 24 hours at room temperature and 40 oC. Meanwhile, it was found that the rate of AgNPs formation increased rapidly under the sunlight. The effects of the synthesis factors on the AgNPs formation were investigated. The suitable conditions for the synthesis of AgNPs using F.J. extract were determined as follows: F.J. extract was mixed with AgNO3 1.75 mM solution with the volume ratio of 3.5 AgNO3 solution/1.5 F.J. Extract, stirred 300 rpm for 150 minutes at 40 oC under sunlight illumination. At these conditions, AgNPs showed high crystalline structure with the average size of 15.9 nm. The antibacterial activity of silver nanoparticles was determined by agar well diffusion method against E. coli and B. subtilis bacteria. The green synthesized AgNPs performed high antibacterial activity against both bacteria.  


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Gaurav Sharma ◽  
Nakuleshwar Dut Jasuja ◽  
Manoj Kumar ◽  
Mohammad Irfan Ali

The present study explores biological synthesis of silver nanoparticles (AgNPs) using the cell-free extract ofSpirulina platensis. Biosynthesised AgNPs were characterised by UV-Vis spectroscopy, SEM, TEM, and FTIR analysis and finally evaluated for antibacterial activity. Extracellular synthesis using aqueous extract ofS. platensisshowed the formation of well scattered, highly stable, spherical AgNPs with an average size of 30–50 nm. The size and morphology of the nanoparticles were confirmed by SEM and TEM analysis. FTIR and UV-Vis spectra showed that biomolecules, proteins and peptides, are mainly responsible for the formation and stabilisation of AgNPs. Furthermore, the synthesised nanoparticles exhibited high antibacterial activity against pathogenic Gram-negative, that is,Escherichia coli, MTCC-9721;Proteus vulgaris, MTCC-7299;Klebsiella pneumoniae, MTCC-9751, and Gram-positive, that is,Staphylococcus aureus, MTCC-9542;S. epidermidis, MTCC-2639;Bacillus cereus, MTCC-9017, bacteria. The AgNPs had shown maximum zone of inhibition (ZOI) that is31.3±1.11inP. vulgaris. Use of such a microalgal system provides a simple, cost-effective alternative template for the biosynthesis of nanomaterials of silver in a large scale that could be of great use in biomedical applications.


2019 ◽  
Vol 20 (1) ◽  
pp. 182
Author(s):  
Dian Susanthy ◽  
Sri Juari Santosa ◽  
Eko Sri Kunarti

This paper describes the antibacterial performance of silver nanoparticles (AgNPs) which have been synthesized by using p-aminobenzoic acid as reducing and stabilizing agent simultaneously. The silver nitrate with various concentrations was reacted with pH 11-adjusted p-aminobenzoic acid with a concentration of 5 × 10–3 mol L–1 for 30 min in a boiling water bath. The synthesized AgNPs were characterized by UV-Vis spectrophotometry, Transmission Electron Microscope (TEM), and Particle Size Analyzer (PSA). The antibacterial performance of the synthesized AgNPs was evaluated by agar well diffusion method on Escherichia coli and Staphylococcus aureus. The higher silver nitrate concentration, the bigger the nanoparticle size, the wider particle size distribution, and the higher number of AgNPs formed. AgNPs synthesized from higher silver nitrate concentration had higher antibacterial activity. It is an indication that the antibacterial activity of AgNPs is mainly controlled by the silver ion concentration which influences the AgNPs particle size and existence of silver ion in the AgNPs colloidal solution


Author(s):  
A. Kaczmarek-Pawelska ◽  
K. Winiarczyk ◽  
J. Mazurek

Purpose: In this work our aim was to reveal the relationship between sodium alginate concentration and crosslinking level, also the ratio of release of the antibacterial additives: silver nanoparticles and metronidazole. Moreover, we examine obtained hydrogel as a potential dressing material for regenerative medicine. Design/methodology/approach: In the research specimens of hydrogels were tested to define their mechanical and physicochemical properties like antibacterial activity against gramnegative Escherichia coli and gram-positive Staphylococcus aureus, viscosity and conductivity. Findings: The concentration of alginate and presence of antibacterial additives influence on the crosslinking level. Mechanical properties of hydrogels are similar to human skin. Only hydrogels with addition of metronidazole and AgNP inhibits bacteria growth after 18 h. In case of gram-negative Escherichia coli both of the aseptic additives inhibits bacteria growth, but sodium alginate hydrogel with silver nanoparticles gives better results in tests with grampositive Staphylococcus aureus. Research limitations/implications: The presence of metronidazole in hydrogel, especially its incorporation and binding with mannuronic and guluronic acid residues must be clarified in more advanced research. Practical implications: Obtained results shows that sodium alginate hydrogels with 0.1mg/ml of alginate, due to its properties are proper as a dressing material. Based on the results, and more advanced tests with metronidazole, we can consider dressing design. Originality/value: Unique value of this work is that we completed the gap in knowledge about the relation of crosslinking level and mechanical properties with are crucial to proper tissue healing and addition of popular aseptic agents.


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