Modification of Ti implant surface for cell proliferation and cell alignment

Surface properties of implants are the keys for ensuring their long-lasting anchorage to the tissue. This study aims to develop a novel implant surface microstructure with high biocompatibility and ability of guided tissue formation. By a photolithography method, gold (Au) grids (1 x 1 mm² square lattices, 10 μm in grid-line width) were deposited on titanium substrates. They were oxidized with H₂O₂ solution to yield titania (anatase) layer, and the Au grid formed channels due to larger molar volume of anatase than Ti. L-Cysteine and type I collagen were then immobilized on them to yield the target substrates, CHT-Au-cys-col. Apatite deposited within 3 days when they were soaked in Kokubo's simulated body fluid, regardless of the protein coating, but not on the bottom of the Au channel. Osteoblast-like MC3T3-E1 cells were cultured on the CHT-Au-cys-col substrates, showing that (1) the cysteine-collagen coating promoted cell attachment and proliferation, and (2) the Au channels were filled with the cells which were aligned along the channel direction and were connected to the neighboring cells as well as attached to the channel wall with cytoplasmic extensions. The results thus ensured filopodial guidance for the substrates.