title: Graphene nanoplatelet-induced strengthening of ultrahigh molecular weight polyethylene and biocompatibility in vitro.
abstract: Graphene nanoplatelets (GNPs) are added as reinforcement to ultrahigh molecular weight polyethylene (UHMWPE) with an intended application for orthopedic implants. Electrostatic spraying is established as a potential fabrication method for synthesizing large-scale UHMWPE-GNP composite films. At a low concentration of 0.1 wt % GNP, the composite film shows highest improvement in fracture toughness (54%) and tensile strength (71%) as compared to UHMWPE. Increased GNP content of 1 wt % leads to improvement in elastic modulus and yield strength but fracture toughness and tensile strength are reduced significantly at higher GNP content. The strengthening mechanisms of the UHMWPE-GNP system are highly influenced by the GNP concentration, which dictates its degree of dispersion and extent of polymer wrapping. The fraction of GNPs oriented along the tensile axis influences the elastic deformation, whereas the wrapping of polymer and GNP-polymer interfacial strength determines the deformation behavior in the plastic regime. The cytotoxicity of GNP to osteoblast is dependent on its concentration and is also influenced by agglomeration of particles. Lowering the concentration of GNPs in UHMWPE improves the biocompatibility of the composite surface to bone cells. The survivability of osteoblasts deteriorates up to 86% on 1 wt % GNP containing surface, whereas much smaller (6-16%) reduction is observed for 0.1 wt % GNP over 5 days of incubation.
authors.affiliation: Plasma Forming Laboratory, Mechanical and Materials Engineering, Florida International University, Miami, Florida 33174, United States.
authors.forename: Debrupa
authors.initials: D
authors.lastname: Lahiri
authors.forename: Rupak
authors.initials: R
authors.lastname: Dua
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhang
authors.forename: Ignacio
authors.initials: I
authors.lastname: de Socarraz-Novoa
authors.forename: Ashwin
authors.initials: A
authors.lastname: Bhat
authors.forename: Sharan
authors.initials: S
authors.lastname: Ramaswamy
authors.forename: Arvind
authors.initials: A
authors.lastname: Agarwal
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D002460:Cell Line; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D010006:Osteoblasts / Q000166:cytology; D011095:Polyethylenes / Q000737:chemistry*; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D001672:Biocompatible Materials; D011095:Polyethylenes; C111601:ultra-high molecular weight polyethylene; D006108:Graphite