title: The impact of the RGD peptide on osteoblast adhesion and spreading on zinc-substituted hydroxyapatite surface.
abstract: The incorporation of zinc into the hydroxyapatite structure (ZnHA) has been proposed to stimulate osteoblast proliferation and differentiation. Another approach to improve cell adhesion and hydroxyapatite (HA) performance is coating HA with adhesive proteins or peptides such as RGD (arginine-glycine-aspartic acid). The present study investigated the adhesion of murine osteoblastic cells to non-sintered zinc-substituted HA disks before and after the adsorption of RGD. The incorporation of zinc into the HA structure simultaneously changed the topography of disk's surface on the nanoscale and the disk's surface chemistry. Fluorescence microscopy analyses using RGD conjugated to a fluorescein derivative demonstrated that ZnHA adsorbed higher amounts of RGD than non-substituted HA. Zinc incorporation into HA promoted cell adhesion and spreading, but no differences in the cell density, adhesion and spreading were detected when RGD was adsorbed onto ZnHA. The pre-treatment of disks with fetal bovine serum (FBS) greatly increased the cell density and cell surface area for all RGD-free groups, overcoming the positive contribution of zinc to cell adhesion. The presence of RGD on the ZnHA surface impaired the effects of FBS pre-treatment possibly due to competition between FBS proteins and RGD for surface binding sites.
authors.affiliation: Brazilian Center for Physics Research, Xavier Sigaud 150, Urca, RJ 22290-180, Brazil. elena@cbpf.br
authors.forename: Elena
authors.initials: E
authors.lastname: Mavropoulos
authors.forename: Moema
authors.initials: M
authors.lastname: Hausen
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Costa
authors.forename: Gutemberg
authors.initials: G
authors.lastname: Alves
authors.forename: Alexandre
authors.initials: A
authors.lastname: Mello
authors.forename: C A
authors.initials: CA
authors.lastname: Ospina
authors.forename: M
authors.initials: M
authors.lastname: Mir
authors.forename: José M
authors.initials: JM
authors.lastname: Granjeiro
authors.forename: Alexandre M
authors.initials: AM
authors.lastname: Rossi
mesh_terms: D000327:Adsorption; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D020099:Coated Materials, Biocompatible / Q000737:chemistry / Q000494:pharmacology*; D017886:Durapatite / Q000737:chemistry* / Q000494:pharmacology; D008422:Materials Testing; D051379:Mice; D009842:Oligopeptides / Q000494:pharmacology*; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D012710:Serum Albumin, Bovine / Q000737:chemistry; D013499:Surface Properties / Q000187:drug effects; D054457:Tissue Scaffolds / Q000737:chemistry; D015032:Zinc / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D020099:Coated Materials, Biocompatible; D009842:Oligopeptides; D012710:Serum Albumin, Bovine; C047981:arginyl-glycyl-aspartic acid; D017886:Durapatite; D015032:Zinc