Preparation of bacterial cellulose impregnated with silver nanoparticles as an antimicrobial wound dressing

Abstract

Bacterial cellulose was produced by Acetobacter xylinum (TISTR 975). Bacterial cellulose is an interesting material for using as a wound dressing since it provide moist environment to a wound resulting in better wound healing. However, bacterial cellulose itself had no antimicrobial activity to prevent wound from infection. To achieve antimicrobial activity, silver nanoparticles were impregnated into the bacterial cellulose by immersing the bacterial cellulose in silver nitrate solution. Sodium borohydride was then used to reduce the absorbed silver ion (Ag+) inside of bacterial cellulose to metallic silver nanoparticles (Ag0). Silver nanopartilces displayed an optical absorption band around 420nm. The red shift and broadening of the optical absorption band was observed when the mole ratio of NaBH4 to AgNO3 (NBH4:AgNO3) was decreased, indicating the increase in particle size and particles size distribution of silver nanoparticles that was investigated by transmission electron microscope. The formation of silver nanoparticles was also evdenced by X-ray diffraction. The antimicrobial activity of the silver nanoparticle-impregnated bacterial cellulose was measured by two methods. The first is an inhibition zone method, growth inhibition ring of Staphylococcus aurous and Escherichia coli were 3.5 and 2 mm, respectively. The second method is a colony forming unit count method, 99.7% reduction in viable Escherichia coli and 99.9% reduction in viable Staphylococcus aurous were observed after 24 hours.