Bi-layered constructs of poly(glycerol-sebacate)-beta-tricalcium phosphate for bone-soft tissue interface applications

Abstract

This study aims to establish a facile protocol for the preparation of a bi-layered poly(glycerol-sebacate) (PGS)/beta-tricalcium phosphate (beta-TCP) construct and to investigate its potential for bone-soft tissue engineering applications. The layered structure was prepared by distributing the ceramic particles within a prepolymer synthesized in a microwave reactor followed by a cross-linking of the final construct in vacuum (<10 mbar). The vacuum stage led to the separation of cross-linked elastomer (top) and ceramic (bottom) phases. Results showed that addition of beta-TCP particles to the elastomer matrix after the polymerization led to an increase in compression strength (up to 14 +/- 2.3 MPa). Tensile strength (sigma), Young's modulus (E), and elongation at break (%) values were calculated as 0.29 +/- 0.03 MPa and 0.21 +/- 0.03; 038 +/- 0.02 and 1.95 +/- 0.4; and 240 +/- 50% and 24 +/- 2% for PGS and PGS/beta-TCP bi-layered constructs, respectively. Morphology was characterized by using Scanning Electron Microscopy (SEM) and micro-computed tomography (mu-CT). Tomography data revealed an open porosity of 35% for the construct, mostly contributed from the ceramic phase since the elastomer side has no pore. Homogeneous beta-TCP distribution within the elastomeric structure was observed. Cell culture studies confirmed biocompatibility with poor elastomer-side and good bone-side cell attachment. In a further study to investigate the osteogenic properties, the construct were loaded with BMP-2 and/or TGF-beta 1. The PGS/beta-TCP bi-layered constructs with improved mechanical and biological properties have the potential to be used in bone-soft tissue interface applications where soft tissue penetration is a problem. (C) 2016 Elsevier B.V. All rights reserved.