Fabrication and characterization of a sponge-like asymmetric chitosan membrane as a wound dressing

A novel asymmetric chitosan membrane has been prepared by immersion-precipi tation phase-inversion method and evaluated as wound covering. This new typ e of chitosan wound dressing which consists of skin surface on top-layer su pported by a macroporous sponge-like sublayer was designed. The thickness o f the dense skin surface and porosity of sponge-like sublayer could be cont rolled by the modification of phase-separation process using per-evaporatio n method. The asymmetric chitosan membrane showed controlled evaporative wa ter loss, excellent oxygen permeability and promoted fluid drainage ability but could inhibit exogenous microorganisms invasion due to the dense skin layer and inherent antimicrobial property of chitosan. Wound covered with t he asymmetric chitosan membrane was hemostatic and healed quickly. Histolog ical examination confirmed that epithelialization rate was increased and th e deposition of collagen in the dermis was well organized by covering the w ound with this asymmetric chitosan membrane. The results in this study indi cate that the asymmetric chitosan membrane thus prepared could be adequatel y employed in the future as a wound dressing. (C) 2000 Elsevier Science Ltd . All rights reserved.