The Synthesis of Silver Nanoparticles

The rapid, eco-friendly, non-pathogenic, economical protocol of using plant to produce silver nanoparticles has drawn the attention of the scientist because of providing a single step technique for the processes of biosynthesis method.

Combining of biomolecules such as proteins, enzymes, polysaccharides, alkaloids, amino acids, tannings, phenolics, saponins, terpenoids and vitamins, which are already found in, plant extracts having all the medicinal values yet complex in chemical structures. For the synthesis of nanoparticles the protocol involves: Collection of the part of plant and it was washed thoroughly twice or thrice with tap water; followed by the use of distilled water to remove any debris. The clean part of plant will be shade-dried for 10-15 days and after drying, using a domestic blender it will be powdered. For the preparation of the plant broth, 20g of the dried powder is boiled in distilled water following the hot percolation method. The result is then filtered until no material will appear in the broth. The AgNO3 solution added to the plant extract, the reduction of ions would be monitored using UV-visible spectra (Ahmed et al., 2016)

Antimicrobial property of silver nanoparticles and its mechanism

Against a wide range of over 650 microorganisms, silver is a well-known antimicrobial agent against different classes of gram-negative and positive bacteria viruses or even fungi. Recently, silver is being use in the form of nanoparticles and it was found out of all other metal with antimicrobial properties that silver has the most effective action against bacteria and it is also least toxic to the environment. With this characteristics and good effect as antimicrobial, silver nanoparticles are synthesized using various plant extract against different microbes (Ahmed et al., 2016)

The antimicrobial properties of silver nanoparticles depend on the size and environmental conditions such as the size, pH and ionic strength and also capping agent. Silver must be in its ionized form in order to have any antimicrobial properties. Silver ions form with nucleic acids and interact with the nucleosides. All forms of silver are in one-way sources of silver ions; these ions are incorporated with substances. There are references showing the electrostatic attraction between nanoparticles and bacterial cells it suggested being most preferable bactericidal agent. It is shown how the nanoparticles go inside the membrane and penetrating into the cells causing damage to its cell wall. The reason for its antibacterial property is its ability to cause bacterial cell lysis. (Ahmed et al., 2016)

Gram-positive bacteria are unlikely a target of silver than gram-negative bacteria. This is because of peptidoglycan molecules of the cell wall; it is thicker than the cell wall of gram-negative bacterial. Both of the silver nanoparticles and silver ions by interfering with disulphide bonds it can change its three dimensional structure of proteins. Green synthesis over chemical and physical method has been advancing for it is cost effective, non-toxic and there is no need in using high energy and toxic materials. (Ahmed et al., 2016)