Bactericidal Antibacterial Mechanism of Plant Synthesized Silver, Gold and Bimetallic Nanoparticles

Abstract

As the field of nanomedicine develops and tackles the recent surge in antibiotic resistance, there is a need to have an in-depth understanding and a synergistic view of research on the effectiveness of a metal nanoparticle (NP) as an antibacterial agent especially their mechanisms of action. The constant development of bacterial resistance has led scientists to develop novel antibiotic agents. Silver, gold and its bimetallic combination are one of the most promising metal NPs because they show strong antibacterial activity. In this review we discuss the mode of synthesis and the proposed mechanism of biocidal antibacterial activity of metal NPs. These mechanisms include DNA degradation, protein oxidation, generation of reactive oxygen species, lipid peroxidation, ATP depletion, damage of biomolecules and membrane interaction.

Facile Green, Room-Temperature Synthesis of Gold Nanoparticles Using Combretum erythrophyllum Leaf Extract: Antibacterial and Cell Viability Studies against Normal and Cancerous Cells

“…This can be attributed to oxidative stress due to the generation of reactive oxygen species causing the detachment of the membrane due to cytoplasm shrinkage. This ultimately leads to a cell wall rupture that culminates in cell death [37][38][39] A similar result was observed with K. pneumoniae (Figure 8C).…”

Biosynthesis of Silver Nanoparticles by Aspergillus terreus: Characterization, Optimization, and Biological Activities

“…Therefore, the development of new antimicrobial agents is strongly demanded. AgNPs are significant nanomaterials with excellent antimicrobial activity that ensues from cell wall and membrane disruption, damage of nucleic acid, and generation of reactive oxygen species (ROS) (Rai et al, 2016;Fanoro and Oluwafemi, 2020).…”

Antimicrobial Properties of Lepidium sativum L. Facilitated Silver Nanoparticles

“…Nanoparticles can be prepared by green methods and are utilized as antimicrobials or drug carriers [ 2 , 12 , 13 , 14 ]. The mechanisms of antimicrobial activity of silver nanoparticles (AgNP) and gold nanoparticles were investigated in recent papers [ 15 , 16 , 17 ]. AgNP and silver ions may coexist and inhibit especially Gram-negative bacteria [ 18 , 19 , 20 , 21 ].…”

“…The size of AgNP is determined by the stability and adsorption pattern of coating/capping agents on the Ag surface [ 18 ]. Strong reducing agents result in faster reaction rates, smaller, more stable NP with a narrow size distribution, and better microbial inhibition [ 17 ]. An agglomeration of AgNP reduces antimicrobial properties and is induced by the storing, aging, or degradation of the capping agent [ 18 ].…”

“…The size of AgNP depends on the pH level, concentration of silver ions, effectivity, and synergistic mechanisms of the available phytochemicals during the green synthesis [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ]. The plant constituents can enhance the antimicrobial properties of the AgNP [ 17 ].…”