title: Influence of purified multiwalled carbon nanotubes on the mechanical and morphological behavior in poly (L-lactic acid) matrix.
abstract: Poly (L-latic acid) (PLLA) is a bioresorbable polymer widely used as a biomaterial, but its fragility can limit its use. An alternative is to produce polymer nanocomposites, which can enhance the mechanical properties of polymeric matrix, resulting in a material with differentiated properties. In this work, PLLA based nanocomposites containing 0.25, 0.5 and 1.0wt% of purified multiwalled carbon nanotubes (p-MWCNTs) were prepared by the solvent casting method. The morphology and mechanical properties results show an improvement in strain at break for 0.25 and 0.5wt% p-MWCNTs and an increase in stiffness and elastic modulus for all compositions. Nanocomposites presented a p-MWCNTs agglomeration; however, there was a good stress transfer between PLLA and p-MWCNTs, which was confirmed by the increase in the hardness and elastic modulus. Atomic force microscopy analysis indicated an increase in roughness after nanotube addition. The in vitro biological study showed that PLLA/p-MWCNTs nanocomposites are cytocompatible with osteoblasts cells. The capacity of PLLA nanocomposites to stimulate osteogenesis was investigated by alkaline phosphatase (ALP) activity assay. Higher ALP activity was found on osteoblasts cultured on nanocomposites with 0.25 and 0.5wt% p-MWCNT compared to neat PLLA, confirming that PLLA cytocompatibility was improved on these compositions. Finally, our results showed that by a simple and inexpensive solvent casting method, it is possible to manufacture biofunctional nanocomposites devices with potential for orthopedic applications.
authors.affiliation: Department of Materials Engineering, Faculty of Mechanical Engineering, University of Campinas, 13083-860 Campinas, SP, Brazil. Electronic address: lealcv5@gmail.com.
authors.forename: C V
authors.initials: CV
authors.lastname: Leal
authors.affiliation: Solid State Chemistry Laboratory, Institute of Chemistry, University of Campinas, P.O. Box 6154, 13081-970 Campinas, SP, Brazil; Brazilian Nanotechnology National Laboratory (LNNano), Brazilian Center for Research in Energy and Materials (CNPEM), 1308-970 Campinas, SP, Brazil.
authors.forename: D S T
authors.initials: DST
authors.lastname: Martinez
authors.affiliation: Faculty of Medical Sciences, Pontifical Catholic University of São Paulo - PUC-SP, 18030-095 Sorocaba, SP, Brazil.
authors.forename: B A
authors.initials: BA
authors.lastname: Más
authors.affiliation: Solid State Chemistry Laboratory, Institute of Chemistry, University of Campinas, P.O. Box 6154, 13081-970 Campinas, SP, Brazil.
authors.forename: O L
authors.initials: OL
authors.lastname: Alves
authors.affiliation: Department of Materials Engineering, Faculty of Mechanical Engineering, University of Campinas, 13083-860 Campinas, SP, Brazil; Faculty of Medical Sciences, Pontifical Catholic University of São Paulo - PUC-SP, 18030-095 Sorocaba, SP, Brazil.
authors.forename: E A R
authors.initials: EAR
authors.lastname: Duek
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D008422:Materials Testing; D053761:Nanocomposites / Q000737:chemistry*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D011091:Polyesters / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D037742:Nanotubes, Carbon; D011091:Polyesters; C033616:poly(lactide)
keywords: Carbon nanotubes; Cytocompatibility; Nanocomposites; Poly (L-lactic acid); Toxicity