scholarly journals Green synthesis of silver nanoparticles and evaluation of their anti-bacterial activities: use of Aloe barbadensis miller and Ocimum tenuiflorum leaf extracts

2021 ◽  
Vol 6 (1) ◽  
pp. 52-67
Author(s):  
Saurabh Sharma ◽  
Kuldeep Kumar ◽  
Naveen Thakur

Abstract The presence of various phytochemicals makes the leaf extract-based green synthesis advantageous to other conventional methods, as it facilitates the production of non-toxic by-product. In the present study, leaf extracts from two different plants: Aloe barbadensis miller and Ocimum tenuiflorum, were used to synthesise Ag nanoparticles. The absorbance at 419-432 nm from UV-visible spectroscopy indicates the formation of Ag in the synthesised samples. The effect of precursors’ concentration on the stability, size and shape of the synthesised samples has also been investigated at constant heating temperature, stirring time, and the pH of the solution. The TEM results showed that all the synthesised samples of nanoparticles demonstrated stability with a size range of 7-70 and 9-48 nm with Aloe barbadensis miller and Ocimum tenuiflorum leaf extracts, respectively. The formation of smaller Ag nanoparticles due to utilisation of different precursor concentration and leaf extracts was also explained. The synthesised samples’ anti-bacterial activity was examined against the pathogens, Bacillus subtilis, Staphylococcus aureus, and Escherichia coli. In general, the green synthesis approach established a prospective for developing highly stable Ag nanoparticles with rigid particle shape/size distribution from different leaf extracts for the development of better anti-bacterial agents.

Author(s):  
Sankar S ◽  
Ganga Krishnan

The green synthesis of nanomaterials is becoming much popular as a result of worldwide problems associated with environmental concerns. In the present work, leaf extract of Barbadensis Miller, (commonly known as Aloe vera) was used for bio-reduction of silver ions to silver nanoparticles. Aloe vera extract and AgNO3 solution in different volumes were treated and it resulted in the reduction of Ag+ ions to Ag metal atoms, which further accumulated as Ag nanoparticles. The prepared nanoparticles were characterized by UV-vis spectroscopy, SEM, FT-IR spectroscopy and XRD analysis. The present study established that the shape and size of the silver nanoparticles can be effectively controlled and modulated using green synthesis technique. The scope of the prepared particles for anti-microbial applications were also investigated.


2021 ◽  
Vol 151 ◽  
pp. 106107
Author(s):  
Soolmaz Soleimani ◽  
Ali Jannesari ◽  
Morteza Yousefzadi ◽  
Arash Ghaderi ◽  
Adnan Shahdadi

Author(s):  
Raja Selvaraj ◽  
Shraddha Pai ◽  
Gokulakrishnan Murugesan ◽  
Sadanand Pandey ◽  
Ruchi Bhole ◽  
...  

AbstractThe reach of nanotechnology has permeated into a range of disciplines and systematically revolutionized many manufacturing techniques. Today, nanoparticles are fabricated using varied approaches, each with its pros and cons. Of them, the green synthesis approach has been very effective in terms of overall economics and the stability of nanoparticles. The current study investigates the use of the leaf extract of Bridelia retusa for the synthesis of iron oxide nanoparticles. Typical of these nanoparticles, no specific peak was discernible on employing UV–visible spectroscopy. The size, morphological features, and crystallinity of the nanoparticles were determined by employing scanning electron microscopy and electron diffraction spectroscopy. Almost uniformly sized at 38.58 nm, the nanoparticles were spherical, constituting elemental iron at 11.5% and elemental oxygen at 59%. Their relative composition confirmed the nanoparticles to be iron oxide. X-ray diffraction studies showed the particles to be hexagonal and rhombohedral, estimating the crystallite size at 24.27 nm. BET analysis put the pore volume at 0.1198 cm3/g and pore diameter at 7.92 nm. The unique feature of the nanoparticles was that the specific surface area was 75.19 m2/g, which is more than 12 times higher than commercial α-Fe2O3. The participation of a variety of biochemicals in the leaf extract towards the reduction-cum-stabilization was confirmed using FTIR analysis. The Fenton-like catalytic activity of the nanoparticles was put to test by attempting to degrade crystal violet dye, which was completely achieved in 270 min. The kinetics of the degradation was also modelled in the study.


2021 ◽  
pp. 111414
Author(s):  
Jalaja Prasad Malavika ◽  
Chellappan Shobana ◽  
Murugesan Ragupathi ◽  
Ponnuchamy Kumar ◽  
Yun Sung Lee ◽  
...  

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4041
Author(s):  
Adriana Cecilia Csakvari ◽  
Cristian Moisa ◽  
Dana G. Radu ◽  
Leonard M. Olariu ◽  
Andreea I. Lupitu ◽  
...  

Cannabis sativa L. (hemp) is a plant used in the textile industry and green building material industry, as well as for the phytoremediation of soil, medical treatments, and supplementary food products. The synergistic effect of terpenes, flavonoids, and cannabinoids in hemp extracts may mediate the biogenic synthesis of metal nanoparticles. In this study, the chemical composition of aqueous leaf extracts of three varieties of Romanian hemp (two monoecious, and one dioecious) have been determined by Fourier-Transformed Infrared spectroscopy (FT-IR), high-performance liquid chromatography, and mass spectrometry (UHPLC-DAD-MS). Then, their capability to mediate the green synthesis of silver nanoparticles (AgNPs) and their pottential antibacterial applications were evaluated. The average antioxidant capacity of the extracts had 18.4 ± 3.9% inhibition determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and 78.2 ± 4.1% determined by 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS™) assays. The total polyphenolic content of the extracts was 1642 ± 32 mg gallic acid equivalent (GAE) L−1. After this, these extracts were reacted with an aqueous solution of AgNO3 resulting in AgNPs, which were characterized by UV−VIS spectroscopy, FT-IR, scanning electron microscopy (SEM-EDX), and dynamic light scattering (DLS). The results demonstrated obtaining spherical, stable AgNPs with a diameter of less than 69 nm and an absorbance peak at 435 nm. The mixture of extracts and AgNPs showed a superior antioxidant capacity of 2.3 ± 0.4% inhibition determined by the DPPH• assay, 88.5 ± 0.9% inhibition as determined by the ABTS•+ assay, and a good antibacterial activity against several human pathogens: Escherichia coli, Klebsiella pneumoniae, Pseudomonas fluorescens, and Staphylococcus aureus.


2017 ◽  
Vol 10 (4) ◽  
pp. 250-256 ◽  
Author(s):  
Erico R. Carmona ◽  
Noelia Benito ◽  
Tanya Plaza ◽  
Gonzalo Recio-Sánchez

2009 ◽  
Vol 71 (1) ◽  
pp. 113-118 ◽  
Author(s):  
Naznin Ara Begum ◽  
Samiran Mondal ◽  
Saswati Basu ◽  
Rajibul A. Laskar ◽  
Debabrata Mandal

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Akshay Rajeev Geetha ◽  
Elizabeth George ◽  
Akshay Srinivasan ◽  
Jameel Shaik

Production of silver nanoparticles from the leaf extracts ofPimenta dioicais reported for the first time in this paper. Three different sets of leaves were utilized for the synthesis of nanoparticles—fresh, hot-air oven dried, and sun-dried. These nanoparticles were characterized using UV-Vis spectroscopy and AFM. The results were diverse in that different sizes were seen for different leaf conditions. Nanoparticles synthesized using sun-dried leaves (produced using a particular ratio (1 : 0.5) of the leaf extract sample and silver nitrate (1 mM), resp.) possessed the smallest sizes. We believe that further optimization of the current green-synthesis method would help in the production of monodispersed silver nanoparticles having great potential in treating several diseases.


2021 ◽  
Vol 891 ◽  
pp. 111-115
Author(s):  
Maradhana Agung Marsudi ◽  
Farah Fitria Sari ◽  
Pandu Mauliddin Wicaksono ◽  
Adinda Asmoro ◽  
Arif Basuki ◽  
...  

In this work, silver nanoparticles have been successfully synthesized using simple and environmentally friendly ‘green synthesis’ method using Indonesian wild honey as mediator. Particle count and size can be optimized by varying the silver nitrate precursor and honey concentration, with the help of sodium hydroxide as pH regulator. Based on X-ray diffraction (XRD) result, crystalline structure of Ag has been confirmed in sample with impurities from AgCl. Based on dynamic light scattering (DLS) and transmission electron microscopy (TEM) results, it was found that the smallest average particles size of AgNPs (117.5 nm from DLS and 11.1 nm from TEM) was obtained at sample with 5% w/v of honey and 0.5 mM of AgNO3.


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