Albumin loaded PEO coatings on Ti - Potential as drug eluting systems

Protein release potential of plasma electrolytic oxidation coatings formed on commercially pure titanium directly loaded with bovine serum albumin was investigated. Four types of coatings with thicknesses of 5 and 15 μm, graded porosity, roughness and composition were studied. The TiO2 coatings were enriched with calcium (3.7-11.1 at.%) and phosphorus (1.5-6.5 at.%). Albumin delivery capacity evaluated during 48 h appears to depend on coating composition, rather than on volume porosity. The coating with Ca/P ratio of 4.0 and no crystalline CaP compounds liberated BSA faster than non-coated Ti CP control in the first 12 h and eluted the entire load in 48 h. The coatings with Ca/P ratio of 1.5-2.0 liberated about 15% of the load over the same period, independently of the surface and volume porosity. Albumin adhesion to the surface and, consequently, retention has been related to its interaction with Ca and P in the coatings. PEO coatings have potential for incorporation and release of growth factors, antibiotics, anti-inflammatory agents, etc. This strategy can be applied in the biomedical field in order to reduce dental implant associated pathologies.