title: Graphene nanoplatelet-reinforced silicone for the valvular prosthesis application.
abstract: Newly developed elastomer heart valves have been shown to better re-create the flow physics of native heart valves, resulting in preferable hemodynamic responses. This emergence has been motivated in part by the recent introduction of percutaneous valve approaches in the clinic. Unfortunately, elastomers such as silicone are prone to structural failure, which drastically limits their applicability the development of a valve prosthesis. To produce a mechanically more robust silicone substrate, we reinforced it with graphene nanoplatelets (GNPs). The nanoplatelets were introduced into a two-part silicone mixture and allowed to cure. Cytotoxicity and hemocompatibility tests revealed that the incorporation of GNPs did not adversely affect cell proliferation or augment adhesion of platelets on the surface of the composite materials. Static mechanical characterization by loading in the tensile direction subsequently showed no observable effect when graphene was utilized. However, cyclic tensile testing (0.05 Hz) demonstrated that silicone samples containing 250 mg graphene/L of uncured silicone significantly improved (p<0.05) material fatigue properties compared with silicone-only controls. This finding suggests that for the silicone-graphene composite, static loads were principally transferred onto the matrix. On the other hand, in cyclic loading conditions, the GNPs were recruited effectively to delay failure of the bulk material. We conclude that application of GNPs to extend silicone durability is useful and warrants further evaluation at the trileaflet valve configuration.
authors.affiliation: Tissue Engineering, Mechanics, Imaging, and Materials Laboratory, Department of Biomedical Engineering, Florida International University, Miami, FL, USA.
authors.forename: Makensley
authors.initials: M
authors.lastname: Lordeus
authors.affiliation: Tissue Engineering, Mechanics, Imaging, and Materials Laboratory, Department of Biomedical Engineering, Florida International University, Miami, FL, USA.
authors.forename: Angie
authors.initials: A
authors.lastname: Estrada
authors.affiliation: Tissue Engineering, Mechanics, Imaging, and Materials Laboratory, Department of Biomedical Engineering, Florida International University, Miami, FL, USA.
authors.forename: Danique
authors.initials: D
authors.lastname: Stewart
authors.affiliation: Tissue Engineering, Mechanics, Imaging, and Materials Laboratory, Department of Biomedical Engineering, Florida International University, Miami, FL, USA.
authors.forename: Rupak
authors.initials: R
authors.lastname: Dua
authors.affiliation: Department of Mechanical and Materials Engineering, Florida International University, Miami, FL, USA.
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Nanomechanics and Nanotribology Laboratory, Mechanical and Materials Engineering Department, Florida International University, Miami, FL, USA.
authors.forename: Arvind
authors.initials: A
authors.lastname: Agarwal
authors.affiliation: Department of Biomedical Engineering, Florida International University Miami, Florida, USA.
authors.forename: Sharan
authors.initials: S
authors.lastname: Ramaswamy
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D001792:Blood Platelets / Q000166:cytology*; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology*; D006108:Graphite / Q000737:chemistry*; D006350:Heart Valve Prosthesis; D008422:Materials Testing; D053758:Nanoparticles; D011474:Prosthesis Design; D051381:Rats; D012826:Silicone Elastomers / Q000737:chemistry*; D013314:Stress, Mechanical
chemical_list: D001672:Biocompatible Materials; D012826:Silicone Elastomers; D006108:Graphite