Hydration and preferential molecular adsorption on titanium in vitro

• Published in: Biomaterials 1992, Vol.13 (8), p.553-561
• Main Authors: Healy, Kevin E., Ducheyne, Paul
• Format: Article
• Language: English
• Subjects: Adsorption; Biocompatible Materials; Biological and medical sciences; Blood - metabolism; Humans; In Vitro Techniques; Materials Testing; Medical sciences; Prostheses and Implants; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Solutions; Spectrum Analysis; surface chemistry; Surface Properties; Technology. Biomaterials. Equipments. Material. Instrumentation; Titanium; Water
• ISSN: 0142-9612; 1878-5905
• DOI: 10.1016/0142-9612(92)90108-Z

Surface sensitive spectroscopies, Auger electron and X-ray photoelectron (XPS), were used to determine changes in titanium oxide composition, oxide stoichiometry and adsorbed surface species as a function of exposure to human serum in a balanced electrolyte (serum/SIE) and 8.0 mM ethylenediaminetetraacetic acid in a balanced electrolyte (EDTA/SIE) at 37°C. Before immersion, the oxide was near ideal TiO 2, covered by two types of hydroxyl groups: acidic OH(s) with oxygens doubly coordinated to titanium and basic Ti-OH groups singly coordinated. After extended exposure to both solutions, up to 5000 h (ca. 208 d), the surface concentration of OH groups increased and non-elemental P appeared. The P LVV Auger transition and P 2p spectra indicated the peak positions were similar to reference phosphate compounds. The adsorbed phosphate species were presumed to be either Ti-H 2PO 4 or Ti-HPO 4 −. The XPS data suggested that a lipoprotein and/or glycolipid film was adsorbed to the specimens exposed to serum/SIE. Analysis of the preferential lipoprotein/glycolipid adsorption using electrostatic bonding concepts contributed to the refinement of the hierarchical model for the Ti-tissue interface. The salient features are that Ti metal is not in direct contact with the biological milieu, rather there is a gradual transition from the bulk metal, near-stoichiometric oxide, Ca and P substituted hydrated oxide, adsorbed lipoproteins and glycolipids, proteoglycans, collagen filaments and bundles to cells.