## 7 Bacterial Cellulose  
Bacterial cellulose (BC), also known as microbial cellulose (MC), is an inexpensive polysaccharide biopolymer of linear \(\beta\)-1,4-glucan chains, which is produced at a high yield by Gram-negative bacteria strains. This type of cellulose has a very similar structure as plant-extracted cellulose, with minor chemical and physical properties' differences, such as a higher degree of polymerization in BC than plant-extracted cellulose [113; 114; 115]. BC is made of assembled microfibril bundles of hundreds of polyglucan chains and has an average fiber diameter of 20-100 nm, a much lower fiber diameter than plant-extracted cellulose, resulting in a significantly higher available surface area [114; 116]. BC is used in a wide range of fields and applications, especially in biomedical applications, such as cornea and bone scaffolds, vessel grafts, diagnostic tools, and wound healing [114; 117; 118].  
BC offers unique properties that have turned it into one of the most sought-after biomaterials for various biomedical applications [118; 119]. The characteristics that make BC a highly versatile biomaterial include high effective surface area, and a hydrophilic nature that gives BC a high liquid loading capacity, together with non-toxicity, biocompatibility, and abundant sources. Its natural structure also closely mimics many biological tissue properties, it has an ability for cell adhesion regulation, and its antigen immobilization capability is high for biosensor applications [82; 115; 116; 120]. Additionally, BC production leads to very high purity and does not involve harsh chemicals, which further eliminates the chance for any residual cytotoxic impurity [120]. Most of the capabilities mentioned above are very promising features for wound-healing applications [115; 120].  
BC offer enormous potentials for wound-dressing applications and has been one of the top choices for wound-dressing biomaterials in recent years, as it can provide mechanical stability and flexibility, promotes cell proliferation, retain liquids associated with wounds, allows gas exchange due to high porosity and permeability, and controls wound exudates, while not inducing any undesirable inflammatory response from the host tissue [116; 119]. Another essential aspect of BC is its potential for loading and controlled release of drugs, exploited in various forms of BC-based dressings and scaffolds [121; 122]. Despite these advantages and the presence of a variety of commercial BC-based wound dressings such as Membracell(r), BC shows no activity against bacterial infections, and it has a very rapid drug release profile due to higher than optimal biodegradability. Although it is a reasonably biocompatible material, it has been shown that in various wound-healing applications, its cell and tissue biocompatibility still have room for improvement [114; 120; 123]. Main strategies to circumvent these issues include surface modifications, immobilization of cell adhesion molecules such as RGD molecules, and combination with other biomaterials to prepare nanocomposite materials [114; 115]. Additionally, anti-microbial components such as anti-microbial drugs have been addressed [124; 125]. Like other cellulose derivatives, BC nanofiber synthesis and hydrogel formation are the main fabrication strategies for wound-dressing applications, which will be addressed [116; 125; 126].