Characterization of antibacterial bacterial cellulose composite membranes modified with chitosan or chitooligosaccharide

To synthesize biomaterials for antibacterial applications, chitosan (CS) and chitooligosaccharide (COS) were successfully incorporated into bacterial cellulose (BC) matrix respectively. The representative Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli) were selected to evaluate the antibacterial effects of the composite membranes. The results manifested BC-CS and BC-COS membranes exhibited remarkable antibacterial properties against both bacteria with the inhibition ratio of 99.99 +/- 0.01% (S. aureus) and 99.99 +/- 0.01% (E. coli) for BC-CS, 99.64 +/- 0.18% (S. aureus) and 90.56 +/- 0.06% (E. coli) for BC-COS. The morphology obtained by scanning electron microscopy (SEM) showed BC-CS and BC-COS composite membranes possessed lower porosity and denser structure in comparison to pure BC. Moreover, in contrast with BC-CS, BC-COS performed better mechanical properties and also displayed stronger ABTS radical scavenging capacity of 92.62 +/- 2.85%. These results suggested that the development of BC-COS composite membrane would open up the possibility for the antibacterial applications in food and medical fields.