## 5 Cellulose-Based Biomaterials in Wound-Healing Augmentation
### CA-Based Nanofibers  
Various nanofibers have been fabricated as a membranous mat to cover skin wounds using various natural, semi-synthetic, and synthetic polymers. CA is another polymer used to fabricate nanofibers for wound-dressing, alone or in combination with other polymers. [PERSON] and colleagues fabricated membranous mats for wound-dressing with electrospinning a CA solution in a mixture of acetic acid/acetone solvents (3:1). Nanofibers with a concentration of 10% to 14% (_w_/_v_) CA were produced, and in mats with the highest concentration of CA, no beads were found. To load tetracycline hydrochloride in nanofibers, 2 _w_/_v_/% of the drug was dissolved in the acetic acid/acetone mixture (3:1). The loaded antibiotic inhibited the growth of both Gram-negative and Gram-positive bacteria on the mat. These nanofibers showed a remarkable ability to absorb high amounts of water in examinations. Cytotoxicity was also investigated using human skin fibroblasts against a tissue culture without the membrane. The results showed more than 90% of cell viability for the membrane after 48 h compared to the control. Generally, these tetracycline-loaded mats proved high water uptake and hydrophilic properties and excellent antibacterial activity as a wound-dressing in in vitro studies [39; 40]. In various studies, CA nanofibers have shown proper mechanical strengths and benefits in wound-dressing alone. Various other studies have examined the results of their association with additional materials and polymers on wound-healing. One of these attempts by [PERSON] et al. examined the effect of different concentrations (0.005, 0.01, 0.05, and 0.1 wt.%) of emodin on CA nanofibers. This emodin-loaded mat morphology did not differ much from that of neat mats, indicating that emodin was well-compatible with CA polymer. Although the diameters of emodin-loaded nanofibers increased with emodin content, this increase was not significantly different from the diameters of neat nanofibers. At the concentration of 0.1 wt.% of emodin, the highest amount of release was observed. Besides the non-toxicity feature, these emodin-loaded mats showed enhanced collagen synthesis at concentrations of 0.05 and 0.1 wt.% compared to neat CA mats [41]. In another study by [PERSON] et al., different amounts of Manuka honey were incorporated in CA nanofibers. The results showed that increasing the amount of Manuka honey increases the antibacterial and antioxidant activities of these nanofibers and their diameters. It is also worth noting that the neat CA mat's strength was higher than the Manukahoney-loaded mat, which was mostly attributed to the lack of mechanical interaction between Manuka honey and nanofibers. Water uptake and water vapor transmission processes, which play an essential role in wound-healing, were disrupted in Manuka honey-containing mats due to diameter increase and surface reduction of nanofibers, causing wound dehydration and healing disruption. However, in vitro studies have shown that cell growth and proliferation rates in these mats were higher than those of the neat mats. Despite their enhanced cytocompatibility and antibacterial activities, Manuka honey-loaded CA mats' weakness lies in their unfavorably increased diameter and lower hydrophilicity compared to neat mats. Therefore, so far, more research was required to find a combination of materials for fabricating mats with anti-microbial and antioxidant properties and a high ability to absorb, retain, and transfer water [42]. [PERSON] and colleagues used propolis-coated nanofibrous mats, which are also plant-based honeybees and have high antibacterial and antioxidant properties. The CA/poly(caprolactone) nanofibrous mats were impregnated with propolis. They had an inhibiting effect on the growth of both Gram-negative and Gram-positive bacteria, in addition to a high capacity to absorb and retain water for hydrating the wound. These results made the fabricated mats a suitable dressing for diabetic wounds, burns, and skin defects [43].