title: Bone regeneration performance of surface-treated porous titanium.
abstract: The large surface area of highly porous titanium structures produced by additive manufacturing can be modified using biofunctionalizing surface treatments to improve the bone regeneration performance of these otherwise bioinert biomaterials. In this longitudinal study, we applied and compared three types of biofunctionalizing surface treatments, namely acid-alkali (AcAl), alkali-acid-heat treatment (AlAcH), and anodizing-heat treatment (AnH). The effects of treatments on apatite forming ability, cell attachment, cell proliferation, osteogenic gene expression, bone regeneration, biomechanical stability, and bone-biomaterial contact were evaluated using apatite forming ability test, cell culture assays, and animal experiments. It was found that AcAl and AnH work through completely different routes. While AcAl improved the apatite forming ability of as-manufactured (AsM) specimens, it did not have any positive effect on cell attachment, cell proliferation, and osteogenic gene expression. In contrast, AnH did not improve the apatite forming ability of AsM specimens but showed significantly better cell attachment, cell proliferation, and expression of osteogenic markers. The performance of AlAcH in terms of apatite forming ability and cell response was in between both extremes of AnH and AsM. AcAl resulted in significantly larger volumes of newly formed bone within the pores of the scaffold as compared to AnH. Interestingly, larger volumes of regenerated bone did not translate into improved biomechanical stability as AnH exhibited significantly better biomechanical stability as compared to AcAl suggesting that the beneficial effects of cell-nanotopography modulations somehow surpassed the benefits of improved apatite forming ability. In conclusion, the applied surface treatments have considerable effects on apatite forming ability, cell attachment, cell proliferation, and bone ingrowth of the studied biomaterials. The relationship between these properties and the bone-implant biomechanics is, however, not trivial.
authors.affiliation: Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft, The Netherlands; FT Innovations BV, Braamsluiper 1, 5831 PW Boxmeer, The Netherlands. Electronic address: s.aminyavari@tudelft.nl.
authors.forename: Saber
authors.initials: S
authors.lastname: Amin Yavari
authors.affiliation: Orthopaedic Research Laboratory, Department of Orthopaedic, Erasmus University Rotterdam Medical Centre, Rotterdam, The Netherlands.
authors.forename: Johan
authors.initials: J
authors.lastname: van der Stok
authors.affiliation: Prometheus, Division of Skeletal Tissue Engineering, Bus 813, O&N1, Herestraat 49, KU Leuven, 3000 Leuven, Belgium; Tissue Engineering Laboratory, Skeletal Biology and Engineering Research Center, Bus 813, O&N1, Herestraat 49, KU Leuven, 3000 Leuven, Belgium; Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Yoke Chin
authors.initials: YC
authors.lastname: Chai
authors.affiliation: KU Leuven, Department of Mechanical Engineering, Section Production Engineering, Machine Design and Automation (PMA), Celestijnenlaan 300B, 3001 Leuven, Belgium; LayerWise NV, Grauwmeer 14, 3001 Leuven, Belgium.
authors.forename: Ruben
authors.initials: R
authors.lastname: Wauthle
authors.affiliation: Department of Tissue Regeneration, MIRA Institute for Biomedical, Technology and Technical Medicine, University of Twente, PO Box 217, 7500AE Enschede, The Netherlands.
authors.forename: Zeinab
authors.initials: Z
authors.lastname: Tahmasebi Birgani
authors.affiliation: Department of Tissue Regeneration, MIRA Institute for Biomedical, Technology and Technical Medicine, University of Twente, PO Box 217, 7500AE Enschede, The Netherlands.
authors.forename: Pamela
authors.initials: P
authors.lastname: Habibovic
authors.affiliation: Department of Orthopaedic, University Hospitals KU Leuven, UZ Pellenberg, Weligerveld 1, 3212 Lubbeek, Belgium.
authors.forename: Michiel
authors.initials: M
authors.lastname: Mulier
authors.affiliation: Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44 - PB 2450, B-3001 Heverlee, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: Schrooten
authors.affiliation: Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft, The Netherlands; Orthopaedic Research Laboratory, Department of Orthopaedic, Erasmus University Rotterdam Medical Centre, Rotterdam, The Netherlands; Department of Orthopedics and Dept. Rheumatology, UMC Utrecht, Heidelberglaan100, 3584CX Utrecht, The Netherlands.
authors.forename: Harrie
authors.initials: H
authors.lastname: Weinans
authors.affiliation: Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft, The Netherlands.
authors.forename: Amir Abbas
authors.initials: AA
authors.lastname: Zadpoor
mesh_terms: D000293:Adolescent; D000818:Animals; D001031:Apatites / Q000494:pharmacology; D001861:Bone Regeneration / Q000187:drug effects*; D018786:Bone Substitutes / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D002478:Cells, Cultured; D006358:Hot Temperature; D006801:Humans; D006851:Hydrochloric Acid / Q000494:pharmacology; D008297:Male; D009929:Organ Size / Q000187:drug effects; D010521:Periosteum / Q000166:cytology / Q000187:drug effects / Q000648:ultrastructure; D016062:Porosity; D017208:Rats, Wistar; D012972:Sodium Hydroxide / Q000494:pharmacology; D012996:Solutions; D013052:Spectrometry, X-Ray Emission; D013464:Sulfuric Acids / Q000494:pharmacology; D013499:Surface Properties; D054457:Tissue Scaffolds / Q000737:chemistry; D014025:Titanium / Q000737:chemistry / Q000494:pharmacology*; D055114:X-Ray Microtomography
chemical_list: D001031:Apatites; D018786:Bone Substitutes; D012996:Solutions; D013464:Sulfuric Acids; D012972:Sodium Hydroxide; D014025:Titanium; C033158:sulfuric acid; D006851:Hydrochloric Acid
keywords: Bone grafting; Bone regeneration; Nanotopography; Selective laser melting; Surface chemistry; Surface–cell interaction