**5. Mechanism of action of silver nanoparticles**

### **5.1 AgNP's antimicrobial MOA**

When AgNP reaches toward cell they release Ag+ ions. These released ion then interact with sulfur and phosphorus containing compound present in cell wall. This lead to disarranged cell wall formation and small pits forms in the cell wall. Formed pit gives access to entry of ions and other foreign material to entry into cell. This increase intracellular osmotic pressure. As pressure built up in the cell, it begins to swell. Finally all these event lead to bursting of cell wall and cell lysis take place. This type of antimicrobial activity is more in gram −ve cell than gram +ve cell. As gram +ve cell have more cross linked peptidoglycan layer and teichic acid in their cell wall. The gram −ve cell have less or no peptidoglycane layer and have more lipopolysaccharide in their cell wall. So the AgNP's easily interact with gram −ve cell due less barrier [72].

#### **5.2 AgNP's anticancer MOA**

As described in above when pit formation takes place in the cell wall, the Ag+ ions released by AgNP's get entered into cell. Then they reaches to mitochondria where they interact with thiolgoups and bind to NADPH dehydrogenase enzyme and liberates ROS. These formed ROS in mitochondria interacted with respiratory enzymes damage ATP formation and respiratory cycle of cell. Formed ROS also interact with protein, sulfur and phosphorus containing cell constituent. Also these formed ROS also bind to phosphorus elements of DNA and RNA which lead to inhibit cell replication and protein synthesis. Due to binding with DNA aggregation of damage protein sysnthesis which lead to cell death. Another possible action is by autophagy. AgNP's have ability to induce autophagy by accumulation of autophagolysosmes in human ovarian cancer cell. This autophagy work by mainly 2 ways; at lower level they increases cell life i.e. surviving rate, but when its level increase it lead to cell death (**Figure 2**) [73].

**67**

*Silver Nanoparticles: Properties, Synthesis, Characterization, Applications and Future Trends*

*DOI: http://dx.doi.org/10.5772/intechopen.99173*

**6. Factors affecting bactericidal potential of AgNP's**

*Factors affecting to the bactericidal effect of silver nanoparticles.*

showing multiple bactericidal actions [74].

**7. Charactrisation of AgNP's**

**7.1 Visual and UV: Visible study**

the specific range of 400–475 nm [75].

**7.2 FTIR analysis**

**Figure 3.**

Primarily morphology i.e. size and shape along with reactivity of AgNP's were responsible for bactericidal potential of AgNP's. Size and surface are inversely proportional to each other as size decreases area increases leads of rapid rise in surface-area to volume ratio. Bactericidal potential inhibit cell wall and free radicals Ag-thiol groups of enzymes Preventing biofilm formation Intercalates between bases Attaching to the surface of the cell membrane Bacterial peptides that can affect cell signaling Attaches to 30 s subunit (**Figure 3**). Silver nanoparticles

To ascertain either AgNPs are developed or not visual and calorimetric appearance of samples checked by UV–Visible spectrophotometer before and after formulation of AgNPs at different time intervals. Before synthesis of AgNPs silver nitrate is colorless and herbal extract has definite color. Once AgNPs synthesized silver nitrate solution develop yellowish brown color after interacting with herbal extract which is confirmed by surface Plasmon resonance SPR and UV visible absorption in

FTIR spectroscopy is an investigational tool to determine/conform functional

groups priesnt in the moiety which is characteristic of that compound. Major

**Figure 2.** *Anticancer mechanism of action of silver nano particles.*

*Silver Nanoparticles: Properties, Synthesis, Characterization, Applications and Future Trends DOI: http://dx.doi.org/10.5772/intechopen.99173*

**Figure 3.** *Factors affecting to the bactericidal effect of silver nanoparticles.*
