# Evaluation of Keratin/Bacterial Cellulose Based Scaffolds as Potential Burned Wound Dressing
## 3 Results and Disscusion  
### BC and Kertose Preparation  
The synthesis of cellulose by _Komagataeibacter xylinum_ is carried out by polymerization and crystallization, both enzymatic catalysts [47; 49]. The authors reported that a _Komagataeibacter xylinum_ cell (Gram-negative, aerobic, and cylindrical bacterium) produces BC, as a result of acetic acid fermentation, developing a polymerization rate of 200,000 glucose molecules/second. Nanometric size of cellulose filaments, good mechanical strength and chemical purity determine the selection of bacterial cellulose that can be constituted from the biomaterial point of view. Bacteria synthesize cellulose because it retains a high amount of moisture, which prevents dehydration of the bacterium, ensuring its vitality for a long period of time. Further, cellulose captures the carbon dioxide molecules resulting from cellulose synthesis, ensuring the bacteria float on the surface of the water, thus having easy access to oxygen in the air; being aerobic, this means good nutrition at the interface with atmospheric air. Due to its opaque nature, cellulose film protects the bacteria from the destructive and dangerous effect of UV radiation [49]. Alternatively, by developing cellulose in water, a barrier is formed that inhibits colonization of the environment by other bacteria which discourages unwanted competition with the host bacterium. The obtained biomaterial consists of BC in the form of a nanofibrils and keratin veil. The procedure involves avoiding the rejection of keratin by the patient's immune system as a foreign body reaction; respectively the burning of keratin achieves the condition of sterility. By treating with water at 150 \({}^{\circ}\)C, inside the capsule, a pressure of 4.9 atmospheres (about 48,10\({}^{4}\) Pa) is developed [50], which determines the hydrolytic degradation of keratin. After this process, \(\beta\)-keratose and \(\gamma\)-keratose are obtained. \(\beta\)-keratose contains high molecular weight proteins, with disulfide cross-linkages which determine its insolubility. This fraction may also contain partially oxidized peptide chains or peptides with a percentage of splinted disulfide bonds. This structure facilitates obtaining of the \(\beta\)-keratose hydrogel. The second fraction, \(\gamma\)-keratose, consists of fragments oxidized keratin and cleaved into small molecules, usually cysteine derivatives. \(\beta\)-keratose hydrogel and partially a \(\gamma\)-keratose solution were used in this study. It has been found that \(\gamma\)-keratose obtained by hydrolysis of human hair has acidic pH. For the qualitative evaluation of the protein composition and dispersion of the \(\gamma\)-keratin, a conductometric titration with NaOH was performed. The titration curve (triplicates) is illustrated in Figure 1.  
It can be observed four domains with molecular fractions. According to the equivalence formula, the calculated normality for each domain is  
\[\text{N}_{\text{1 strong acids}}\times\text{Sample volume}=\text{N NaOH}\times \text{V}_{\text{eq1}} \tag{2}\]  
where N1 strong acids represents the normality of part 1 components (equiv./liter); N NaOH is the normality of the sodium hydroxide solution used in the titration (0.1 in this case); \(\text{V}_{\text{eq1}}=\) the graphically determined volume of equivalence in domain 1 (mL) illustrated. From Formula (2), the number of strong acid equivalents is calculated:  
\[\text{N}_{\text{1 strong acids}}=(\text{N NaOH}\times\text{V}_{\text{eq1}})/ \text{Sample volume} \tag{3}\]  
Similarly, for the other domains respectively, the range 2 between pH = 0.75-1.7, the range 3 between 1.7 and 3.2 and the range 4 between 3.2 and 4.8 were obtained. Table 1 shows the values of equivalents/liter number obtained on the four domains. Table 1 illustrates the values of the acid equivalents on the domains obtained by conductance titration of \(\gamma\)-keratose solution, after the hydrolytic degradation treatment.