In vitro biodegradability and mechanical properties of bioabsorbable bacterial cellulose incorporating cellulases

Bacterially produced cellulose is being actively studied as a novel scaffold material for wound care and tissue engineering applications. Bioabsorbability of the scaffold material is desired to enable improved restoration of targeted tissue. Recently, a bioabsorbable bacterial cellulose (BBC) incorporating cellulase enzymes has been demonstrated. It was revealed that some cellulases may lose up to 90% of their activity if present in a suboptimal pH environment. Therefore, a key challenge in the practical implementation of this approach rests in compensating for the variation in the wound or tissue pH, which may significantly reduce the activity of some enzymes. In this work, buffer ingredients were incorporated into the bacterial cellulose in order to create a more optimal pH microenvironment for the preferred acid cellulases, which are significantly less active at the biological pH 7.4. The results demonstrated that incorporation of buffer ingredients helped to retain the activity of the cellulases. The glucose released from degraded materials was also increased from 30% without incorporation of buffer ingredients to 97% in the presence of incorporated buffer ingredients at the suboptimal pH environment of 7.4. The use of simulated body fluid and simulated tissue padding, both mimicking the real wound environment, also demonstrated some improvements in terms of material degradation. Measurements of mechanical properties of materials revealed that BBC materials have tensile strength and extensibility similar to human skin, especially when hydrated with saline water prior to use. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.