Abstract: Objective To construct different biomolecule coatings on the surface of pure titanium discs and to find out a proper implant coating. Methods Pure titanium disc was first ground, polished and acid-etched with a mixture of H₂SO₄/H₂O₂(acid-etched group, as the control group). Collagen type Ⅰ (COL), chitosan (CHI), hyaluronic acid (HA) and polyglutamic acid (PGA) were introduced onto this acid-etched surface using layer by layer technique (coating group). Scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), quartz crystal microbalance (QCM) and contact angle measurement were used for surface characterization. After pre-osteoblasts were seeded on the discs, cell attachment, proliferation and differentiation were evaluated. Results SEM analysis demonstrated that the surfaces of different coatings were very smooth and similar. XPS analysis showed that the nitrogen content of different surface was dramatically increased with deposition number. Contact angle measurement showed that the construction of different biomolecules on pure titanium discs did not damage the excellent wettability of the basal surface. Cell attachment, proliferation and differentiation were much stimulated in the coating groups when compared with the acid-etched group. On the other hand, COL-based coatings [Ti-(COL/HA)₅-COL and Ti-(COL/PGA)₅-COL] showed much higher bioactivity compared with CHI-based coatings [Ti-(CHI/HA)₅-CHI and Ti-(CHI/PGA)₅-CHI], and Ti-(COL/HA)₅-COL coating promoted cell attachment, proliferation and differentiation much more than those of Ti-(COL/PGA)₅-COL coating. Conclusion Collagen type Ⅰ, chitosan, hyaluronic acid and polyglutamic acid are successfully constructed on the titanium surface, and Ti-(COL/HA)₅-COL coating shows high bioactivity and may promote implant osseointegration.

Key words: Chitosan, Collagen type Ⅰ, Polyglutamic acid, Hyaluronic acid, Layer by layer technique