Biomimetic polyelectrolyte multilayer ultrathin films to promote osseointegration

The integration between bone and implant plays a key role in several fields, such as maxillofacial, dental and orthopedics. The improvement of the bone/implant interface has been considered with great interest for many years, mostly as relates to titanium-based implants, in which implantation surgery may induce implant infections. Such infections are the main cause of mechanical loosening and incomplete integration of the implant. The bone/implant interface has been mostly improved by physical approaches acting on the surface topography and by chemical and/or biochemical surface modification. The latter approach is focused on the incorporation of organic molecules. The work described here is focused on surface modifications of implants by layer-by-layer (LbL) self-assembly of Collagen I (COL) and Hyaluronic Acid (HA) in order to promote osteogenesis and reduce bacterial infections. This technique allows to coat surfaces of any shape using ultrathin film multilayers oppositely charged polyelectrolytes. The multilayer ultrathin films were initially deposited on a Quartz Chrystal Microbalance surface in order to monitor and optimize fabrication. Subsequently, the multilayer structure has been replicated on Titanium substrates and characterized by SEM and AFM. The coatings have been tested in vitro with 3T3 cells seeded on titanium supports with and without HA/COL structures. The results described here show that structures based on these coatings can improve osteogenesis. The fabrication method is easily reproducible and versatile.