title: A novel nanocomposite polymer for development of synthetic heart valve leaflets.
abstract: A novel nanocomposite polymer with a polycarbonate soft segment (PCU) and polyhedral oligomeric silsesquioxanes (POSS) nanoparticle (POSS-PCU) has been selected for a synthetic heart valve due to its superior biocompatibility and in vivo biostability. However, the development of synthetic heart valves from polymeric materials requires an understanding of the basic mechanical and surface properties of the polymer. In this study, the mechanical properties of POSS-PCU, including tensile strength, tear strength and hardness, were tested and compared to control (PCU). The surface property was analyzed using contact angle measurement and the resistance to platelet adhesion was also investigated. POSS-PCU (hardness 84+/-0.8 Shore A) demonstrated significantly higher tensile strength 53.6+/-3.4 and 55.9+/-3.9Nmm(-2) at 25 and 37 degrees C, respectively) than PCU (33.8+/-2.1 and 28.8+/-3.4Nmm(-2) at 25 and 37 degrees C, respectively). Tensile strength and elongation at break of POSS-PCU was significantly higher than PCU at both 25 and 37 degrees C (P<0.001). POSS-PCU showed a relatively low Young's modulus (25.9+/-1.9 and 26.2+/-2.0Nmm(-2)) which was significantly greater in comparison with control PCU (9.1+/-0.9 and 8.4+/-0.5Nmm(-2)) at 25 and 37 degrees C, respectively, with 100mum thickness. There was no significant difference (P>0.05) in tear strength between POSS-PCU and PCU at 25 degrees C. However, tear strength increased significantly (P<0.001) (at 37 degrees C) as the thickness increased from 100microm (51.0+/-3.3Nmm(-1)) to 200microm (63+/-1.5Nmm(-1)). The surface of POSS-PCU was significantly less hydrophilic than that of PCU.
authors.affiliation: Centre for Nanotechnology, Biomaterials & Tissue Engineering, UCL Division of Surgery & Interventional Science, University College London, London NW3 2PF, UK.
authors.forename: Asmeret G
authors.initials: AG
authors.lastname: Kidane
authors.forename: Gaetano
authors.initials: G
authors.lastname: Burriesci
authors.forename: Mohan
authors.initials: M
authors.lastname: Edirisinghe
authors.forename: Hossein
authors.initials: H
authors.lastname: Ghanbari
authors.forename: Philipp
authors.initials: P
authors.lastname: Bonhoeffer
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Seifalian
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D002478:Cells, Cultured; D055119:Elastic Modulus; D006350:Heart Valve Prosthesis; D006801:Humans; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation*; D017646:Organosilicon Compounds / Q000737:chemistry*; D010316:Particle Size; D010973:Platelet Adhesiveness / Q000502:physiology*; D011076:Polycarboxylate Cement / Q000737:chemistry*; D011474:Prosthesis Design; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D001672:Biocompatible Materials; D017646:Organosilicon Compounds; D011076:Polycarboxylate Cement; C005506:polycarbonate