## 1 Introduction  
The tracheal epithelial layer is a well-known barrier that prevents underlying tissues from external irritants such as allergens, airborne particulates, infectious agents, and noxious gases, and their potential penetration. As a part of the immune system, it facilitates the communication and activities of cells in the innate and adaptive immune system. Therefore, structural or functional alternations occurring in the respiratory epithelium can severely compromise its effectiveness. Diseases that involve the tracheal epithelium include trauma, post-intubation injuries, infection, and inflammation, and chronic diseases such as asthma [1], rhinitis [2], and obstructive pulmonary disease. In asthma, which is known as a common chronic inflammatory disease of the airway, or in the cases of inhaling harmful chemicals or vapors [3], the injuries in the epithelium cause structural changesto the normal architecture of the nasal epithelium, increasing its susceptibility to irritants and decreasing its efficiency in response to respiratory viruses [4]. The consequence of the injuries introduced into the epithelium can even cause the loss of surface epithelium integrity and partial or complete shedding of the epithelium [5]. Therefore, these conditions necessitate epithelium repair or replacement. Treatments using foreign materials [6], noviable tissues, autologous tissues, and various types of tracheal epithelial transplantation have been tried; however, no breakthrough had been achieved. It is thought that tissue engineering strategies can offer alternative solutions by developing tissue-engineered epithelium to be used for epithelial replacement or reconstruction. Ex-vivo-engineered respiratory epithelium has been integral to understanding the pathologies and underlying mechanisms of many respiratory-related diseases. Hence, it can potentially be used for studying drug interactions with the reparatory epithelium and developing regenerative therapies for respiratory epithelium diseases [7]. A tissue-engineered respiratory epithelium construct composed of autologous respiratory epithelium cells, fibroblasts, and plasma from sheep's blood was previously reported in a series of studies, and it was used to replace tracheal mucosal defects in sheep. The postoperative analysis showed encouraging results: immature cilia were found to be present on the surface of epithelial cells. These results indicated that the engineered respiratory epithelium was able to function as a normal tissue, and the presence of autologous fibrin found in blood plasma provided a favorable environment for respiratory epithelial cells adaptation and proliferation [8; 9; 10]. [PERSON] et al. investigated de-epithelialized porcine tracheal tissue that was re-populated with human bronchial epithelial cells and its potential application in tracheal tissue engineering. Their findings showed the feasibility of the de-epithelialization of the porcine trachea using sodium dodecyl sulfate, without compromising the integrity of the underlying cartilage and the viability of residing chondrocytes. They reported that the remaining porcine cartilage supports the growth and proliferation of seeded bronchial epithelial cells over 7 days [11], but the tracheal epithelium being partially removed and the presence of residing viable chondrocytes raise concerns about the immunogenicity and clinical application of such grafts [12]. Cellulose-based material from either plant or bacterial sources is another category of materials being extensively studied for their applicability in tissue engineering in general and tracheal tissue engineering in particular. Cellulose, which is a linear polymer comprising a glucose unit [13], shows favorable properties in supporting the attachment, growth, and proliferation of epithelial cells [14] and chondrocytes [15], and allows infiltration and ingrowth of seeded cells [16].