title: Chemical functionalization of graphene to augment stem cell osteogenesis and inhibit biofilm formation on polymer composites for orthopedic applications.
abstract: Toward designing the next generation of resorbable biomaterials for orthopedic applications, we studied poly(ε-caprolactone) (PCL) composites containing graphene. The role, if any, of the functionalization of graphene on mechanical properties, stem cell response, and biofilm formation was systematically evaluated. PCL composites of graphene oxide (GO), reduced GO (RGO), and amine-functionalized GO (AGO) were prepared at different filler contents (1%, 3%, and 5%). Although the addition of the nanoparticles to PCL markedly increased the storage modulus, this increase was largest for GO followed by AGO and RGO. In vitro cell studies revealed that the AGO and GO particles significantly increased human mesenchymal stem cell proliferation. AGO was most effective in augmenting stem cell osteogenesis leading to mineralization. Bacterial studies revealed that interaction with functionalized GO induced bacterial cell death because of membrane damage, which was further accentuated by amine groups in AGO. As a result, AGO composites were best at inhibiting biofilm formation. The synergistic effect of oxygen containing functional groups and amine groups on AGO imparts the optimal combination of improved modulus, favorable stem cell response, and biofilm inhibition in AGO-reinforced composites desired for orthopedic applications. This work elucidates the importance of chemical functionalization of graphene in polymer composites for biomedical applications.
authors.affiliation: Department of Materials Engineering, ‡Department of Physics, and §Department of Inorganic and Physical Chemistry, Indian Institute of Science , Bangalore 560012 India.
authors.forename: Sachin
authors.initials: S
authors.lastname: Kumar
authors.forename: Shammy
authors.initials: S
authors.lastname: Raj
authors.forename: Elayaraja
authors.initials: E
authors.lastname: Kolanthai
authors.forename: A K
authors.initials: AK
authors.lastname: Sood
authors.forename: S
authors.initials: S
authors.lastname: Sampath
authors.forename: Kaushik
authors.initials: K
authors.lastname: Chatterjee
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D004926:Escherichia coli / Q000187:drug effects* / Q000502:physiology; D006108:Graphite / Q000737:chemistry* / Q000494:pharmacology*; D006801:Humans; D008422:Materials Testing; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000502:physiology; D010006:Osteoblasts / Q000166:cytology* / Q000502:physiology; D010012:Osteogenesis / Q000187:drug effects / Q000502:physiology; D011091:Polyesters / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D000900:Anti-Bacterial Agents; D011091:Polyesters; C016240:polycaprolactone; D006108:Graphite
keywords: antimicrobial properties; graphene; orthopedics; polymer composites; stem cell