%0 Journal Article
%T Permeability of Porous Poly(3-hydroxybutyrate) Barriers of Single and Bilayer Type for Implant Applications
%A Anna Bergstrand
%A Sanna Uppstr£żm
%A Anette Larsson
%J International Journal of Polymer Science
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/958975
%X Poly(3-hydroxybutyrate) (PHB) is a polyester which shows excellent biocompatibility and a PHB material is therefore considered suitable for many biomedical applications. A highly porous PHB material may be designed to facilitate the transport of small molecules and body fluids or serve as a biocompatible temporary barrier. In this study, PHB films with varying degree of porosity and pore interconnectivity were made by solvent casting using water-in-oil emulsion templates of varying composition. The morphology was characterized by SEM and the water permeability of the films was determined. The results show that an increased water content of the template emulsion resulted in a film with increased porosity. A fine tuning of the film morphology of the casted films was achieved by varying the salt content of the water phase of the template emulsion. The porosity of these films was roughly the same but the water permeability varied between and . It was concluded that the major determinant of the water permeability through these films is the pore interconnectivity. Furthermore, we report on the formation and water permeability of bilayer PHB films consisting of a porous layer combined with a dense backing layer. 1. Introduction Poly(3-hydroxybutyrate) (PHB) is considered to be a polymer that has high potential as a biodegradable implant material. The polymer is a well examined thermoplastic polyester of microbial origin which shows excellent biocompatibility in contact with tissue and blood [1¨C5]. The natural presence of low molecular weight PHB and the polymer degradation product, 3-hydroxybutyric acid, in the body is further evidence for the nontoxicity of PHB [6]. Besides the necessary biocompatibility of PHB, the use as an implant requires that the material is degraded during a period of time that is relevant for the application in question. PHB is one of the slowest degrading polyesters since the polymer is highly crystalline, preventing water penetration into the polymer matrix and subsequent scission of polymer chains [7]. An implant made out of PHB material can retain its integrity during an extended period of time in a wet environment and this feature may be attractive for certain applications. PHB has been investigated for many types of medical applications including gastrointestinal patches [8], nerve guides [9, 10], and scaffolds for tissue engineering [11]. The fabrication of highly porous materials with interconnected pores is of great interest in the field of tissue engineering since it enables the passage of fluid and transport of small
%U http://www.hindawi.com/journals/ijps/2014/958975/