Fabrication of alumina membrane coated titanium implants for effective osteointegration

In large-area fractures of the skeletal system, achieving rapid and effective osteointegration depends on the implant surfaces to be used in that region having similar chemical, mechanical, and topographical properties to bone tissue. Titanium-based biomaterials are frequently preferred in clinical use in such cases, and coating these materials with oxide layers having chemical/nanotopographic properties to enhance osteointegration and implantation success rates has been studied for a long time.The aim of this study was to investigate the high and rapid mineralization potential of anodized aluminum oxide (AAO) coated and atomic layer deposition (ALD)-alumina coated titanium substrates in large deformation areas where self-healing is difficult. AAO-coated titanium (AAO@Ti) surfaces were fabricated by anodization in different electrolytes and their osteogenic potential was analyzed in comparison with a pure titanium surface as a control. In order to investigate the effect of the ionic characters acquired by the surfaces through anodization, the oxidized nanotopographic surfaces were also coated with an ultra-thin alumina layer by ALD (ALD@AAO@Ti), a precise and conformal coating vapor deposition technique. Furthermore, pure titanium sample was also coated with pure alumina by ALD (ALD@Ti) to investigate the effect of nanoscale surface morphology. XPS analysis after ALD coating showed that the ionic character of each surface produced by anodization was successfully suppressed. In vitro studies showed that among the substrates studied, the mineralization capacity of MG-63 osteosarcoma cells was highest when incubated on pure AAO@Ti samples (H3PO4_AAO@Ti and ALD@H3PO4_AAO@Ti) anodized in phosphoric acid and treated with ALD. Mineralization on these substrates also increased consistently from day 2 to day 21. Expression levels of osteogenic genes highlighted the ALD@Ti and ALD@H3PO4_AAO@Ti surfaces, while immunocytochemistry analyses emphasized that osteogenic activity was highest on the ALD@H3PO4_AAO@Ti surface. Therefore, as a result of this thesis, it was seen that the best surface with effective and rapid osteointegration potential and the best surface that can be used in implant applications can be the surface produced in phosphoric acid and its ionic identity suppressed.