Dense chitosan surgical membranes produced by a coincident compression-dehydration process

Abstract

High density chitosan membranes were produced via a novel manufacturing process and used as implantable resorbable surgical membranes. The innovative method utilizes the following three sequential steps: (1) casting an acidic chitosan solution within a silicon mold, followed by freezing; (2) neutralizing the frozen acidic chitosan solution in alkaline solution to facilitate polymerization; and (3) applying coincident compression-dehydration under a vacuum. Resulting membranes of 0.2–0.5 mm thickness have densities as high as 1.6 g/cm³. Inclusion of glycerol prior to the compression-dehydration step provides additional physical and clinical handling benefits. The biomaterials exhibit tensile strength with a maximum load as high as 10.9 N at ∼2.5 mm width and clinically relevant resistance to suture pull-out with a maximum load as high as 2.2 N. These physical properties were superior to those of a commercial reconstituted collagen membrane. The dense chitosan membranes have excellent clinical handling characteristics, such as pliability and ‘memory’ when wet. They are semipermeable to small molecules, biodegradable in vitro in lysozyme solution, and the rates of degradation are inversely correlated to the degree of deacetylation. Furthermore, the dense chitosan membranes are biocompatible and resorbable in vivo as demonstrated in a rat oral wound healing model. The unique combination of physical, in vitro, in vivo, and clinical handling properties demonstrate the high utility of dense chitosan membranes produced by this new method. The materials may be useful as surgical barrier membranes, scaffolds for tissue engineering, wound dressings, and as delivery devices for active ingredients.

Keywords:

• chitosan
• membrane
• wound healing
• biodegradation
• resorbable
• mechanical properties
• suture

Acknowledgments

The project described was supported by Grant Number DE017254 from the National Institute of Dental and Craniofacial Research through the SBIR program. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIDCR or the NIH. The innovative manufacturing processes, composition, and uses of the dense chitosan materials of this work are patent pending. All rights are reserved by Agenta Biotechnologies, Inc.