Plant-Mediated Synthesis of Silver Nanoparticles and Their Stabilization by Wet Stirred Media Milling

Abstract

Within this study, a stable nanosuspension of silver nanoparticles (Ag NPs) was prepared using a two-step synthesis and stabilization approach. The Ag NPs were synthesized from a silver nitrate solution using the Origanum vulgare L. plant extract as the reducing agent. The formation of nanoparticles was finished upon 15 min, and subsequently, stabilization by polyvinylpyrrolidone (PVP) using wet stirred media milling was applied. UV-Vis spectra have shown a maximum at 445 nm, corresponding to the formation of spherical Ag NPs. Infrared spectroscopy was used to examine the interaction between Ag NPs and the capping agents. TEM study has shown the formation of Ag NPs with two different average sizes (38 ± 10 nm and 7 ± 3 nm) after the plant-mediated synthesis, both randomly distributed within the organic matrix. During milling in PVP, the clusters of Ag NPs were destroyed, the Ag NPs were fractionized and embedded in PVP. The nanosuspensions of PVP-capped Ag NPs were stable for more than 26 weeks, whereas for the non-stabilized nanosuspensions, only short-term stability for about 1 week was documented.

Green Synthesis of Silver Nanoparticles with Antibacterial Activity Using Various Medicinal Plant Extracts: Morphology and Antibacterial Efficacy

“…426 nm. Similarly, an increase in absorbance intensity was observed with reaction time corresponding to the observation of AgNP green synthesis using O. vulgare [ 31 ].…”

“…The bio-reduction of silver ions to nanosized Ag 0 was aided by aqueous plant extracts of B. vulgaris (BV, root extract), B. nigra (BN, seed extract), C. bursa-pastoris (CBP, leaves extract), L. angustifolia (LA, leaves extract) and O. vulgare (OV, leaves extract) as the reducing agents. The 1:9 ratio (extract/AgNO 3 ) was required to achieve particles with spherical morphology according to the literature [ 31 ]. The primary detection method of bio-reduction of Ag + ions to colloidal nanoparticles (AgNPs) was observed by a visual colour change and confirmed by UV-Vis spectral analysis ( Figure 1 ).…”

“…In this study, we employed medicinal plants used widely in folk medicine from a diverse range of families, including Lamiaceae ( Lavandula angustifolia and Origanum vulgare ), Brassicaceae ( Brassica nigra and Capsella bursa-pastoris ) and Berberidaceae ( Berberis vulgaris ). Regarding the plants used in our study, the successful synthesis of AgNPs using extracts of B. nigra [ 29 ], O. vulgare [ 30 , 31 , 32 , 33 ], B. vulgaris leaf and root aqueous extract [ 34 ], or L. angustifolia flowers extract [ 35 , 36 , 37 ] has been reported. To the best of our knowledge, the extracts from B. vulgaris roots, L. angustifolia leaves and C. bursa-pastoris leaves for the preparation of AgNPs have not been reported.…”

Reducing the Crystallite Size of Spherulites in PEO-Based Polymer Nanocomposites Mediated by Carbon Nanodots and Ag Nanoparticles

“…The prepared Ag NPs display photoluminescence as a result of electron excitation from occupied d-bands into unoccupied states above the Fermi level. Subsequent relaxation through electron–phonon- and hole–phonon-scattering processes result in an energy loss and, consequently, photoluminescent radiative recombination of an electron from an occupied sp band with the hole occurs [64]. The characteristic PL band in both PEO:CNDs and PEO:CNDs:Ag composites was observed to be broad.…”

Green-Synthesized Silver Nanoparticles and Their Potential for Antibacterial Applications

“…In the green synthesis, the reduction procedure is performed by a natural-based material including bacteria, fungi, yeast, plants and plant extracts, or small biomolecules (e.g. vitamins, amino acids, or polysaccharides) [25][26][27]. With the development of reliable methodology to produce nanoparticles, several attempts of in vivo and in vitro synthesis of AgNPs have been realized.…”