# Electrospinning of Chitosan for Antibacterial Applications--Current Trends
## 7 Application Fields of Electrospun Chitosan Nanofibers and Chitosan Derivatives
### Biomedicine  
#### 7.4.1 Wound Dressings  
Wound dressings are topical therapeutic patches that are applied to wounds to help them recover naturally. A variety of natural and synthetic materials are already in use in different structures. Due to their nanofibrous structure, dressings of electrospun fibers can improve wound healing in several ways. They have the ability to absorb undesired fluids from the injured area but also to preserve helpful fluids and proteins inside the wound area. They can additionally guide cell proliferation due to their structure being similar to the composition of collagen fibrils in the extracellular matrix [189]. Their porosity in the size range of nanometers is also able to ensure their breathability and can protect the wound from bacterial penetration [7]. Chitosan-based products are advantageous for use in tissue engineering and wound healing because they are natural antimicrobial components [189]. Nanofibrous products, in particular, are considered for biomedical applications due to their low cost, biodegradability, non-toxicity, and antibacterial characteristics [190]. As mentioned above, the electrospinningning of pure chitosan fibers is difficult for several reasons. Therefore, chitosan was combined with different polymers to obtain high-quality nanofiber mats that are suitable for biomedical applications. Further functionalization of the wound dressings is possible, transporting active substances into wounds and ulcers when these dressings come into contact with the body and supporting wound healing (via the addition of drugs) or preventing infections (via the addition of antibacterial compounds) [189; 190]. A bicomponent nanofibrous mat comprising chitosan and poly(lactic acid) (PLA) was produced by electrospinning. In comparison to a casted chitosan-PLA film, this mat successfully prevented the development of _S. aureus_ and _E. coli_ bacteria in wounds [191]. The core-sheath structure has also been demonstrated to enhance fibroblast reproduction and tissue regeneration [192]. Incorporation of moxifloxacin hydrochloride, an antibiotic with intrinsic antibacterial activity against Gram-positive and Gram-negative bacteria, in electrospun nanofibers from chitosan and PVA significantly increased the antibacterial properties of the product. Unfunctionalized chitosan/PVA nanofiber mats did not show any inhibition zone on the tested agar plates, as chitosan was not able to diffuse in the agar diffusion test. Vibration methods are, therefore, recommended for proving the antibacterial properties of pure chitosan products [118; 192]. It was found that polyaniline (PANI)/chitosan composite membranes help wounds heal by stimulating skin development. Synergistic effects were observed by promoting the growth of both fibroblasts and osteoblasts. [193]. In order to determine the antibacterial properties of this composite material, PANI/chitosan nanofibers were electrospun according to the proper blend ratio, relative humidity, and voltage that lead to stable jet formation. The fibers were then evaluated against two bacteria strains, _E. coli_ and _B. subtilis_. Mats with a high PANI concentration exhibited enhanced bactericidal activity, making the composite membrane a potential candidate for wound dressing applications because of the biocompatibility, electrical charges, and antibacterial properties of the blended materials in use [194]. In another study, electrospinningning was used to produce a membrane of chitosan and silk fibroin (SF). Silk fibroin was used to improve the mechanical characteristics. The membrane inhibited the development of _E. coli_ according to turbidity measurements. The antibacterial activity of chitosan/SF nanofibrons membranes increased dramatically as the percentage of chitosan was raised, which was significantly beneficial to these membranes when employed as wound dressings [195]. Natural substances such as aloe vera have been utilized to enhance the hydrophilicity and antibacterial characteristics of chitosan/PCL nanofibers [196].