title: Oxidative nanopatterning of titanium surfaces promotes production and extracellular accumulation of osteopontin.
abstract: The bone-biomaterial interface has been characterized by layers of afibrillar extracellular matrix (ECM) enriched in non collagenous proteins, including osteopontin (OPN), a multifunctional protein that in bone controls cell adhesion and ECM mineralization. Physical and chemical aspects of biomaterial surfaces have been demonstrated to affect cell-ECM-substrate interactions. The present paper described the ability of oxidative nanopatterning of titanium (Ti) surfaces to control extracellular OPN deposition in vitro. Ti discs were chemically treated by a mixture of H2SO4/H2O2 for either 30 min [Nano(30') Ti] or 4 h [Nano(4h) Ti]. Non-etched Ti discs were used as control. Primary osteogenic cells derived from newborn rat calvarial bone were plated on control and etched Ti and grown under osteogenic conditions up to 7 days. High resolution scanning electron microscopy revealed that treated Ti discs exhibited a nanoporous surface and that areas of larger nanopits were noticed only for Nano(4h) Ti. Large extracellular OPN accumulation were detectable only for Nano(4h) Ti, which was associated with OPN-positive cells with typical aspects of migrating cells. At day 3, quantitative results in terms of areas of OPN labeling were as follows: Nano(4h) Ti > Nano(30') Ti > Control Ti. In conclusion, chemically nanostructured Ti surfaces may support the enhancement of endogenous extracellular OPN deposition by osteogenic cells in vitro depending on the etching time, a finding that should be taken into consideration in strategies to biofunctionalize implant surfaces with molecules with cell adhesion capacity.
authors.affiliation: Ribeirão Preto Dental School, USP - University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Renan de Barros E Lima
authors.initials: Rde B
authors.lastname: Bueno
authors.forename: Patricia
authors.initials: P
authors.lastname: Adachi
authors.forename: Larissa Moreira Spinola de
authors.initials: LM
authors.lastname: Castro-Raucci
authors.forename: Adalberto Luiz
authors.initials: AL
authors.lastname: Rosa
authors.forename: Antonio
authors.initials: A
authors.lastname: Nanci
authors.forename: Paulo Tambasco de
authors.initials: PT
authors.lastname: Oliveira
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000327:Adsorption; D000818:Animals; D000831:Animals, Newborn; D001672:Biocompatible Materials / Q000737:chemistry*; D002448:Cell Adhesion / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D003764:Dental Materials / Q000737:chemistry*; D016326:Extracellular Matrix Proteins / Q000493:pharmacokinetics*; D006861:Hydrogen Peroxide / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology; D010006:Osteoblasts / Q000378:metabolism / Q000502:physiology; D010012:Osteogenesis / Q000502:physiology; D053495:Osteopontin / Q000493:pharmacokinetics*; D010084:Oxidation-Reduction; D051381:Rats; D017208:Rats, Wistar; D013464:Sulfuric Acids / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D003764:Dental Materials; D016326:Extracellular Matrix Proteins; C506897:Spp1 protein, rat; D013464:Sulfuric Acids; D053495:Osteopontin; D006861:Hydrogen Peroxide; D014025:Titanium; C033158:sulfuric acid