# Evaluation of Keratin/Bacterial Cellulose Based Scaffolds as Potential Burned Wound Dressing
## 1 Introduction  
Extensive and deep burn wounds represent a severe pathology, altering the general balance of the patient's status. Complex general and local therapy is required for the re-equilibration of the patients and recovering the protective barrier of the organism. Deep burns occupying over 15-20% from the body surface generate a multiple organ failure with progression to post-combustion shock. The time between the accident and the hospitaladmission of the patient is critical for the future evolution. Any delay in providing the necessary care favors local and general complications and can lead to death [1]. Burned skin opens a huge gate for important loss of fluids, proteins, enzymes, electrolytes, altering the cardio-vascular, digestive, respiratory, and renal functions [2]. Increased blood viscosity generates a higher risk to thromboembolism and wound's bacterial invasion determines multiple organs failure and septic shock. Immediately after the injury, it is crucial to treat the pain, to restore the volume and hemodynamic balance, to correct the cellular hypoxia and prevent the main organs failure. It is equally important to excise the post burn necrosis and the challenge comes from the lack of donor zones sites, the high risk of wound deepening, and bacterial aggression [3,4]. Wound healing is a dynamic process that involves a complex series of events, lasting from the moment of injury to healing and includes increased activity of inflammatory, vascular, connective tissue, and epithelial cells. Wounds generally produce exudates that consist of fluids, cells or other substances that are slowly exuded or discharged from cells or blood vessels [5]. An important part of the clinical success is given by using a suitable biomaterial, with an appropriate mechanical resistance, which cover the wounds and prevent the fluid loss, the bacterial contamination, and stimulate the healing [6]. To cover and protect the burned wounds, usually sterile bandages are used. Recently, new possibilities were discovered such as artificial membranes for temporary wound protection. Another therapeutic solution is the use of autologous skin grafts, harvested from the patient's healthy skin donor zones. This last procedure has the main disadvantage that represents a new aggression for the skin areas and opens new gates for the bacterial invasion [7]. A useful biomaterial for burned wounds needs to respect the biocompatibility, to be able to stimulate the healing in a humid environment, to assure an efficiently antibacterial action without disturbing the biological cellular balance. Technically, a biomaterial offers the chance of biological reconstruction. It may be a scaffold, with a higher mechanical resistance, which functions like a support for skin cells. The cells will initiate the development of a keratinocytes film, which can be used to reconstruct the post burn defect [8,9]. Wound dressings have been fabricated starting from different types of materials and various formats, for example fiber mats and hydrogels, and may contain additives like silver or biological compounds for anti-bacterial properties [10]. Various natural or synthetic materials have been tested for wound healing purpose. Materials based on hyaluron have been demonstrated to promote blood clotting and possess antibacterial properties [11, 12, 13, 14, 15, 16, 17, 18]. Other polysaccharides, including alginates [19, 20], chitosan [21, 22, 23], gelatin [24, 25, 26], and cellulose [27, 28], have also been used to fabricate hydrogels for wound healing. Some synthetic polymers, like polyvinyl alcohol (PVA) [29, 30], poly(ethylene glycol) (PEG), poly(acrylic acid) [31], and poly(lactic acid) [32] were tested and some of them presented antibacterial characteristics and as a hybrid with collagen, fibrin, or chitosan can promote wound regeneration [33, 34, 35]. Various hydrogels have been tested as wound dressings because of their similarity with extracellular matrices (ECM) [36].