Green synthesis of silver nanoparticles: biomolecule-nanoparticle organizations targeting antimicrobial activity

Abstract

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.

Green-Synthesization of Silver Nanoparticles Using Endophytic Bacteria Isolated from Garlic and Its Antifungal Activity against Wheat Fusarium Head Blight Pathogen Fusarium graminearum

“…These bacteria have been used as a biological source in the biosynthesis of AgNPs, but the mechanism of bacteria for AgNPs biosynthesis is still unknown. Interestingly, a lot of previous reports have revealed the existence of various biomolecules that are produced by bacteria such as alkaloids, phenolic compounds, enzymes, co-enzymes, proteins, amino acids, polysaccharides, and vitamins, all of which have been able to act as effective agents for converting Ag + to Ag 0 [19,20,29,30]. Therefore, it could be inferred that these biomolecules that are produced by bacteria may play a key role in the mediation of AgNPs biosynthesis.…”

Electrochemical properties of biogenic silver nanoparticles synthesized using Hagenia abyssinica (Brace) JF. Gmel. medicinal plant leaf extract

“…Metal ions in solution interact with polyphenolic compound and helps in the nucleation and formation of Ag NPs. Formation of nanoparticles is believed to be due to the combinational effect of bioactive compounds of plant extract [27].…”

<p>Silver Nanoparticles for the Therapy of Tuberculosis</p>

“…The antibacterial effect of AgNP, especially in the greensynthesis context (plant, viral, bacterial, fungic, and algal extracts or biomimetic compounds as reducing agents), 183,184 can be, at least partially enhanced by the extra bio-active component introduced in the particle synthesis. 185,186 AgNP can be prepared using elements that possess per se an antibacterial activity. The synergistic effect between AgNP and other and bioactive phytocompounds can be expected in the green-synthesis, leading to antibacterial effects via different mechanisms as those described above.…”

“…Therefore, the enhanced antimicrobial effect of NP synthesized by greenextraction which can be occasionally observed can also be determined by the presence of the bioactive molecules of the synthesis attached on the surface of nanoparticles as stabilizing agent. 186,187 In the green-synthesis of AgNP, the biological extracts are mixed with the metal salt solutions, the bio-extract (containing starch, steroids, sapogenins, flavonoids, terpenoids, amino cellulose, etc.) 188 acts in situ as reducing agents of the silver salts (Ag + ) to form metallic silver Ag 0 , and also as capping agents to provide stability of silver nanoparticles in solution 186,189 and partially can be further be found in the structure of the AgNP as surfacestabilizing ligands.…”

“…186,187 In the green-synthesis of AgNP, the biological extracts are mixed with the metal salt solutions, the bio-extract (containing starch, steroids, sapogenins, flavonoids, terpenoids, amino cellulose, etc.) 188 acts in situ as reducing agents of the silver salts (Ag + ) to form metallic silver Ag 0 , and also as capping agents to provide stability of silver nanoparticles in solution 186,189 and partially can be further be found in the structure of the AgNP as surfacestabilizing ligands. 190 Indeed, in a recent study, Shaik et al 190 tested the efficiency of AgNP synthesized from Origanum vulgar against various bacteria (Escherichia coli, Shigella sonnei, Micrococcus luteus), and fungi (Aspergillus flavus, Alternaria alternate, Paecilomyces variotii, Phialophora alba).…”