scholarly journals A NANOCOMPOSITE BASED ON MICROBIAL SYNTHESIS OF HUMIC PRECURSORS AND OF METAL NANOPARTICLES USED AS AN ANTIMICROBIAL COMPOUND IN SOIL

2019 ◽  
Vol 13 (2) ◽  
pp. 201-210
Author(s):  
Sorin Matei ◽  
Gabi-Mirela Matei ◽  
Gina Cogălniceanu ◽  
Alexandru Brînzan

Soil humic precursors could be considered the most active and mobile fraction and are highly significant to a series of biochemical processes in all types of soil. The microbial biosynthesized humic precursors attracted increasing attention on green synthesis of nanocomposite compounds realized between biopolymers and metal nanoparticles. Silver nanoparticles are the most used engineered nanocomposite serving as antimicrobial agents. In the present study we used aqueous solution of humic precursors synthesized by four microbial consortia (C1-C4) and selected on the basis of high quantities of exometabolites with structural similarities to soil humic acid fraction. The humic precursors were used as capping agents of silver nanoparticles in the nanocompozite synthesis. Biosynthesized humic precursors act as reductive and stabilizative agents of nanoparticles which are found between 5-300nm in size and with spherical preponderant shape. The presence of humus precursors and the biosynthesized silver nanoparticles was confirmed by FTIR and UV-Vis. At a given precursor concentration, the efficiency of nanocomposite synthesis increased with particle concentration and time of reaction, property which can be attributed to the high reduction capacity of humic precursors. The induced antimicrobial effect of exposure to nanocomposites differs due to the size, time of preparation and stability. Stabilization of nanocomposite by specific metal-ligand bonds was obtained in the solution for three months without any precipitate. The antimicrobial effect of nanocomposites was estimated under laboratory agar well diffusion tests against mycotoxigenic soil fungal isolate Aspergillus niger (A27). The green synthesis of nanocomposite material with the best antimicrobial effect against test fungus was realized by microbial consortium C3and C4.

2021 ◽  
pp. 0958305X2198988
Author(s):  
Nur Syakirah Rabiha Rosman ◽  
Noor Aniza Harun ◽  
Izwandy Idris ◽  
Wan Iryani Wan Ismail

The emergence of technology to produce nanoparticles (1 nm – 100 nm in size) has drawn significant researchers’ interests. Nanoparticles can boost the antimicrobial, catalytic, optical, and electrical conductivity properties, which cannot be achieved by their corresponding bulk. Among other noble metal nanoparticles, silver nanoparticles (AgNPs) have attained a special emphasis in the industry due to their superior physical, chemical, and biological properties, closely linked to their shapes, sizes, and morphologies. Proper knowledge of these NPs is essential to maximise the potential of biosynthesised AgNPs in various applications while mitigating risks to humans and the environment. This paper aims to critically review the global consumption of AgNPs and compare the AgNPs synthesis between conventional methods (physical and chemical) and current trend method (biological). Related work, advantages, and drawbacks are also highlighted. Pertinently, this review extensively discusses the current application of AgNPs in various fields. Lastly, the challenges and prospects of biosynthesised AgNPs, including application safety, oxidation, and stability, commercialisation, and sustainability of resources towards a green environment, were discussed.


RSC Advances ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 2673-2702 ◽  
Author(s):  
Anupam Roy ◽  
Onur Bulut ◽  
Sudip Some ◽  
Amit Kumar Mandal ◽  
M. Deniz Yilmaz

In this review, we discuss the recent advances in green synthesis of silver nanoparticles, their application as antimicrobial agents and mechanism of antimicrobial mode of action.


RSC Advances ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 2804-2837
Author(s):  
Chhangte Vanlalveni ◽  
Samuel Lallianrawna ◽  
Ayushi Biswas ◽  
Manickam Selvaraj ◽  
Bishwajit Changmai ◽  
...  

Herein, we have reviewed new findings in the research domain of the green synthesis of silver nanoparticles using different plant extracts and their potential applications as antimicrobial agents covering the literature since 2015.


Antibiotics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 569 ◽  
Author(s):  
Marta Filipa Simões ◽  
Cristiane Angélica Ottoni ◽  
André Antunes

Mycobacterial infections are a resurgent and increasingly relevant problem. Within these, tuberculosis (TB) is particularly worrying as it is one of the top ten causes of death in the world and is the infectious disease that causes the highest number of deaths. A further concern is the on-going emergence of antimicrobial resistance, which seriously limits treatment. The COVID-19 pandemic has worsened current circumstances and future infections will be more incident. It is urgent to plan, draw solutions, and act to mitigate these issues, namely by exploring new approaches. The aims of this review are to showcase the extensive research and application of silver nanoparticles (AgNPs) and other metal nanoparticles (MNPs) as antimicrobial agents. We highlight the advantages of mycogenic synthesis, and report on their underexplored potential as agents in the fight against all mycobacterioses (non-tuberculous mycobacterial infections as well as TB). We propose further exploration of this field.


2020 ◽  
Vol 2020 ◽  
pp. 1-7 ◽  
Author(s):  
Weidong Huang ◽  
Minhui Yan ◽  
Haiming Duan ◽  
Yaling Bi ◽  
Xinxin Cheng ◽  
...  

It is urgent to develop highly efficient and eco-friendly antimicrobial agents for integrated control of phytopathogens. Silver nanoparticles (AgNPs) were synthesized by Ligustrum lucidum leaf extract. UV-vis spectrum showed that there was a strong absorbance at 438 nm. Transmission electron microscopy (TEM) images displayed that synthesized nanoparticles were near spherical with an average size of 13 nm. The antimicrobial effect of AgNPs was evaluated through methods of paper disk diffusion, colony growth, conidia germination, and in vitro inoculation. The 50% inhibition concentration (IC50) of AgNPs against Setosphaeria turcica was 170.20 μg/mL calculated by SPSS 13.0. In addition, it displayed a significant synergistic antifungal effect when AgNPs were combined with epoxiconazole at the ratios of 8 : 2 and 9 : 1. The results of this study provide a novel fungistat not only for comprehensive control of plant fungi but also for reducing chemical pesticides use and avoiding drug-resistant phytopathogen generation.


2021 ◽  
Vol 10 (1) ◽  
pp. 421-429
Author(s):  
Humaira Rizwana ◽  
Mona S. Alwhibi ◽  
Hadeel A. Aldarsone ◽  
Manal Ahmed Awad ◽  
Dina A. Soliman ◽  
...  

Abstract Silver nanoparticles (AgNPs) are widely used for medical applications particularly as antimicrobial agents against multidrug-resistant microbial strains. Some plants stimulate the reduction of Ag ions to AgNPs. In this study, we prepared AgNPs via the green synthesis approach using fenugreek leaves grown in Saudi Arabia. Furthermore, we characterized these AgNPs and evaluated their antimicrobial activities against pathogenic yeast, bacteria, and fungi. The ultraviolet-visible peak at 380 nm confirmed the biosynthesis of NPs. Transmission electron microscopy analyses revealed particle size in the range of 9–57 nm with a spherical shape. Dynamic light scattering results confirm slight aggregation as the average particle size was shown as 68.71 nm and a polydispersity index of 0.083. The energy-dispersive X-ray spectroscopy results showed an intense peak at 3 keV, indicating the presence of elemental AgNPs. The synthesized AgNPs efficiently inhibit the growth of both Gram-positive and Gram-negative bacteria; however, varying degree of inhibition was shown toward fungi. The potent antimicrobial ability of the synthesized NPs can be attributed to their small size and round shape. Among all test organisms, the growth of Candida albicans and Helminthosporium sativum was remarkably affected by AgNPs treatment.


2021 ◽  
Vol 19 (3) ◽  
pp. 247-257
Author(s):  
Yuliya A. Morozova ◽  
Dmitry S. Dergachev ◽  
Mikhail A. Subotyalov

Over the past few decades, nanoparticles of metals, and in particular silver, with a diameter of less than 100 nm have significantly expanded their field of application for various biomedical purposes. So, silver nanoparticles have great potential in a wide range of applications as antimicrobial agents, coatings for biomedical products, carriers for drug delivery, bioengineering, since they have discrete physical properties and wide biochemical functionality. Studies have shown that the size, morphology, stability and properties (chemical and physical) of metal nanoparticles are strongly influenced by the conditions of the experiment, the kinetics of the interaction of metal ions with reducing agents and the adsorption processes of the stabilizer with metal nanoparticles. This review aims to analyze the use of silver nanoparticles in modern medicine based on data from domestic and foreign literature over the past five years. The study confirmed the high biological activity of drugs with nanoserebrum as anti-inflammatory, antimicrobial agents, antifungals, the presence of an inhibitory effect on protozoa, antioxidant and anticancer effects, and substantiated the relevance of use in bioengineering and dentistry. However, rapid advances and advances in technology have led to concerns about the potential risk associated with the use and application of silver nanoparticles to human health and the environment. Therefore, this review attempts to characterize and quantify the potential harmful effects of silver nanoparticles on the health of laboratory animals and humans, and focuses on ways to neutralize or reduce the toxic effects of silver nanoparticles on the human body.


Author(s):  
Pasent Gharib Saad ◽  
Rohan Daniel Castelino ◽  
Vimal Ravi ◽  
Issa Sulaiman Al-Amri ◽  
Shah Alam Khan

Abstract Background Green synthesis of silver nanoparticles (AgNPs) has gained popularity due to the economical and eco-friendly approach associated with it. The aim of the study was to biosynthesize silver nanoparticles using pomegranate peel extract (PPE), quercetin (Q), and gallic acid (GA) and to evaluate their antioxidant, antimicrobial, and cytotoxic activities. Results A sharp color change from yellow to brown, appearance of a peak in a UV spectrum around 413–425 nm, and four intense peaks in XRD spectra matching with the reference silver crystal confirmed the formation of AgNPs. SEM and TEM analysis revealed particles to be mostly spherical with few aggregates. Average particle size distribution and zeta potential was found to be 43.6 nm and −18.01mV, 31.6 nm and −21.5 mV, and 21.7 nm and −27.9 mV for Q-AgNPs, P-AgNPs, and GA-AgNPs, respectively. P-AgNPs showed excellent in vitro antioxidant activity (84.85–89.20%) and cytotoxic activity (100% mortality). P-AgNPs and GA-AgNPs exhibited good antimicrobial activity against the four bacterial strains comparable to the reference antibiotics but Q-AgNPs failed to inhibit the growth of P. vulgaris. Conclusions Omani pomegranate peel extract seems to be a potential and alternative source for the simple, one pot, eco-friendly green synthesis of extracellular stable AgNPs. The synthesized nanoparticles have the potential to be developed as possible antimicrobial agents and antioxidants. Graphical abstract


2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Siavash Iravani ◽  
Behzad Zolfaghari

Recently, development of reliable experimental protocols for synthesis of metal nanoparticles with desired morphologies and sizes has become a major focus of researchers. Green synthesis of metal nanoparticles using organisms has emerged as a nontoxic and ecofriendly method for synthesis of metal nanoparticles. The objectives of this study were production of silver nanoparticles usingPinus eldaricabark extract and optimization of the biosynthesis process. The effects of quantity of extract, substrate concentration, temperature, and pH on the formation of silver nanoparticles are studied. TEM images showed that biosynthesized silver nanoparticles (approximately in the range of 10–40 nm) were predominantly spherical in shape. The preparation of nano-structured silver particles usingP. eldaricabark extract provides an environmentally friendly option, as compared to currently available chemical and/or physical methods.


Author(s):  
Wilson Mbiti Njue ◽  
Jackson Kilonzo Kithokoi ◽  
Jane Mburu ◽  
Henry Mwangi ◽  
Sauda Swaleh

Metal nanoparticles in the field of nanotechnology are of great interest to modern scientific research due to their size effects, medical uses and, catalytic, electronic and optical properties. Green synthesis of metal nanoparticles is a feasible alternative to chemical methods as it is environmentally friendly and cost effective. In continuation with our research on green synthesis of silver nanoparticles using Kenyan medicinal plants, we here report the synthesis of novel silver nanoparticles (AgNPs) on ultrasonic bath using Adansonia digitata leaves extracts and analysis of their antibacterial activity. The nanoparticles were characterized by UV-Vis, High Resolution Transmission Electron Microscopy (HRTEM), FTIR spectroscopy and Energy Dispersive X-ray (EDX). EDX analysis affirmed the nanoparticles were pure silver. Crystalline nature of the nanoparticles was confirmed by bright circular spots in the Selected Area Electron Diffraction (SAED) in HRTEM image. The AgNPs were spherical with an average size 13 nm. FTIR analysis showed strong –C=C- and –OH stretching bands due to compounds capping the nanoparticles. The synthesized AgNPs showed high inhibition zones of 17.1±0.130 mm towards Gram-negative bacteria E. coli and 12.9±0.082mm towards Gram positive bacteria S. aureus. The aqueous A. digitata extract had no effect on growth inhibition of test bacteria. The study showed that the silver nanoparticles synthesized from the plant’s leaves extract had antibacterial activity against both Gram negative and positive pathogenic bacteria. The nanoparticles can be utilized towards developing novel drugs useful in combating pathogens.


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