Characterization of cellulose based sponges for wound dressings

Cellulose based sponges were developed by freeze-drying of regenerated cellulose gels and characterized as a potential wound dressing. Morphological characteristics were analyzed by means of micro-computed tomography. The results showed that the porosity of the sponges reached 75%, the pores were interconnected and their size ranged from 10 to 1200 mu m with a mean pore diameter of 750 mu m. Due to hydrophilicity of cellulose and high specific surface area (14.5 mm(2)/mm(3)) the sponges possess high sorption of simulated wound fluids (approx. 210%) and high water vapour transmission ability. Different active compounds, such as polyphenols from Calendula officinalis or Chamomilla recutita extracts (1 day diffusion experiment), silver nanoparticles (1, 2 and 4 days diffusion experiments) were immobilized into the sponges in order to improve wound dressing performance. Release kinetics of silver nanoparticles and polyphenols from the sponges were investigated. The sponges incorporated with silver, showed antibacterial activity against Staphylococcus epidermidis. Thus, these cellulose based sponges are promising wound dressing materials for fester and infected wounds. (C) 2014 Elsevier B.V. All rights reserved.