## 5 Cellulose-Based Biomaterials in Wound-Healing Augmentation
### CA-Based Nanofibers
Curcumin's distinctive features, such as antibacterial, antifungal, antioxidant, anti-inflammatory, and antitumor properties, have convinced many researchers to strive to fabricate curcumin-containing mats for the wound dressing. The material alone has low solubility and low heat resistance. Studies have established that loading the drug on nanofibrous composites in the presence of poly(vinyl pyrrolidone) (PVP) shows the highest release rate due to the increased solubility induced by this polymer. This fact was emphasized in a study by [PERSON] et al. In their study, curcumin was loaded on CA nanofibrous mats, as well as CA/PVP mats. Mats with PVP released a higher amount of curcumin faster, and they had higher hydrophilicity compared to curcumin-loaded CA nanocomposites. Anti-microbial tests also showed that matrices with a higher release amount of curcumin have higher anti-microbial activity [44]. Thymoquinone is another anti-microbial agent that can inhibit the growth of many microbes at the wound site. Systematic administration of this drug can have lower efficacy and higher side effects than topical drug use. On the other hand, it has some limitations for local use as well. However, loading in scaffolds such as CA nanofibrous mats, which have a high bioavailability, stability, bioactivity, and hydrophilicity, can enhance the treatment outcomes [45]. Although nanofibrous mats made of various polymers are known as a great mechanical and physical barrier for covering wounds, this is not the only requirement for a wound-healing process. Combining an antibacterial agent in a wound-dressing expedites the healing process and prevents possible wound infections or even systemic infections. Poly (lactic acid) (PLA) draws particular attention in biomedical applications, especially for wound-dressing, due to its biocompatibility, biodegradability, as well as mechanical durability and elasticity. However, a severe limitation of PLA is its hydrophobicity and low water absorption capacity. [PERSON] et al. attempted to fabricate a thymoquinone-loaded PLA/CA nanocomposite. They tested the composites on mice in terms of cell proliferation, re-epithelial, and wound site closure speed (Figure 2). Their results were promising. In addition to an optimal anti-microbial activity shown by this nanocomposite mat, H&E staining studies confirmed more tissue granulation and faster re-epithelial for this dressing than the control group [46]. Another nanocomposite was made from polyurethane, CA, and zein materials, presenting higher cell viability and proliferation and blood clotting ability, and hydrophilicity. In addition to that, loading streptomycin onto this nanocomposite mat as an anti-microbial agent provided all the wound requirements to heal. The results of in vitro and in vivo studies of the fabricated mat indicated that all the vital biological and physiological properties for a wound-dressing are enhanced in this nanocomposite [47]. One of the most critical wounds is a diabetic wound. These wounds go through a more extended recovery period and are more likely to become infected since they have inefficient blood flow and nerve conduction. Moreover, in the case of infection of these wounds, infection progression is very high, and the possibility of recovery is lower. Besides, the low blood supply to these wounds makes systemic antibacterial agents less effective and necessitates higher doses of the medication, which leads to more side effects. With this in mind, as far as these diabetic wounds are concerned, proper dressing has critical importance to prevent infection and accelerate its healing process and the provision of the anti-microbial drug for local release at the wound site. Therefore, CA-zein nanocomposites were fabricated containing a high dose of sesamol to be tested on diabetic rats. The in vivo study revealed an accelerated wound-healing improvement in diabetic mice [48]. Another system was a CA/gelatin nanofibrous mat containing berberine.