**3.3 Silver**

*Nanofibers - Synthesis, Properties and Applications*

starts to overcome the surface tension of the fluid. A fine, charged jet of polymer solution is ejected from the tip of the needle as the electrostatic force overcomes the surface tension of the conical droplet. The action between the electric field and surface tension of the fluid outstretches the jet stream and then it encounters a whipping motion and that results in the evaporation of the solvent. This led to the jet stream to be stretched out continuously as a thin and long filament. Subsequently this filament will harden and will be eventually settled onto a grounded collector,

The electro spun nanofibers built-in with antibacterial agents have been fabricated for antimicrobial applications. The electro spun nanofibers exhibit enhanced antimicrobial performance compared to conventional antimicrobial materials. They play significant roles in wound-dressing materials, filtration, tissue scaffolds,

The electro spun nanofibers with antimicrobial properties fabrication methods are grouped into two categories. Antimicrobial nanofibers can be obtained by one step process or by the following two steps. In one stage process, the suspensions with a mixture of antimicrobial agents and polymer undergo electrospinning. The formulation of this homogeneous mixture is censorious to make up a smooth and continuous nanofiber. The properties of electrospinning solutions are affected by antimicrobial agents. Such vital characteristics that play a significant role in the

Whereas in the two steps method include, producing an initial electro spun polymeric nanofibers and then post-functionalizing nanofibers with antimicrobial materials. Multiple functionalization approaches have been managed to link the antimicrobial agents onto surfaces of electro spun nanofibers by using various

Antimicrobial electro spun nanofibers built-in with different antimicrobial agents: including metallic nanoparticles (silver, zinc, titanium, copper, and cobalt),

Volatile oils well known as Essential oils are plant derived concentrated hydrophobic and volatile compounds. They are a combination of different compounds such as carvacrol, eugenol, and cymene derived from aromatic plants. The best examples of essential oils are terpenoids and hydrophobic phenolic compounds [14, 15]. The hydrophobic nature of essential oils decides their activity mechanism against microbes. These essential oils break up into the bacterial plasma membrane lipid bilayer and then disrupt its structure. This alters the permeability of membrane to ions and other cellular contents. Consequently, the proton pump collapses

Sadri and his team prepared PEO nanofibers/electro spun chitosan, to which they linked two distinct types of thyme essential oils into this nanofiber. They used broadleaf and narrow leaf thyme essential oils to their study. The nanofibers/chitosan along with the thyme oils were trialled against *P. aeruginosa* and *Staphylococcus aureus*. After 24 hrs, the inhibition of narrow life was reported as 8 and 15 mm were as in case of broad life it was 10 and 19 mm for *P. aeruginosa* and *S. aureus*, respectively.

carbon nanomaterials, antibiotics, and antimicrobial biopolymers.

and finally results in the development of a uniform fibre (**Figure 2**) [11].

**2.2 Electrospun nanofibers with antimicrobial properties**

protective textiles, and biomedical devices [12].

process and resultant are conductivities and viscosities.

chemical and physical methods [13].

**3. Antimicrobial agents**

and results in cell death [16].

**3.1 Volatile oils**

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Amongst metallic nanoparticles, silver nanoparticles are the most studied and have been demonstrated to be the most effective antimicrobial agents. Ag is a known biocidal agent that is effective against a range of types of fungi, bacteria, and viruses; on the other hand, it is non-hazardous to human cells. The simplest and most frequently used method for combining Ag nanoparticles with electro spun nanofibers is the suspension of Ag nanoparticles directly into the electrospinning polymer solutions [21, 22].

A research team formulated cellulose acetate nanofibers with the use of electrospinning methods. Cellulose acetate nanofibers were transformed into cellulose nanofibers using alkaline hydrolysis. In addition to this, silver nanoparticles were added to the cellulose nanofiber. Developed antibacterial silver cellulose nanofiber activity was examined against *E. coli* and *S. aureus* grown on Lysogeny broth [LB] medium. After 18 hrs of contacting 1% silver nanoparticles, the inhibition zone was spotted with 16- and 14.4-mm diameter against *E. coli* and *S. aureus*, respectively. Besides, it was also proved that antibacterial activities of the Ag nanofibers were directly influenced by the rising concentration of Ag nanoparticle contents [23].
