Biocompatibility and drug delivery efficiency of PEG-b-PCL/hydroxyapatite bilayer coatings on Nitinol superelastic alloy

摘要

A bioactive surface on metallic implants and the capability of drug delivery could promote successful implantation. In this work, biological behavior and drug delivery efficiency of hydroxyapatite (HA)/poly epsilon-caprolactone-polyethylene glycol (PEG-b-PCL) bilayer composite coatings on NiTi alloy were investigated. Scanning electron microscopy images revealed that the electrodeposited HA coating had a dense inner layer and a porous outer layer. It was shown that the polymer can penetrate into the porosities of the HA and increase the water contact angle of the surface. According to the cell culture results, HA/PEG-b-PCL (0.3 mg cm(-2)) coating exhibited the best bioactivity as compared to the HA and other composite coatings with a higher amount of the copolymer. This bilayer coating also showed the best results based on the nano-scratch WA results. Ibuprofen was effectively loaded on the HA/PEG-b-PCL (0.3 mg cm(-2)) film and released into phosphate-buffered saline up to 90% during 20 h. It seems that ibuprofen is released by the copolymer hydration and the bioactive surface of HA appears gradually to support the cells growth.