Contact profilometry and correspondence analysis to correlate surface properties and cell adhesion in vitro of uncoated and coated Ti and Ti6Al4V disks.

A fundamental goal in the field of implantology is the design of specific devices able to induce a controlled and rapid "osseointegration". This result has been achieved by means of surface modifications aimed at optimizing implant-to-bone contact; furthermore, bone cell adhesion on implant surface has been directly improved by the application of biomolecules that stimulate new tissue formation, thus controlling interactions between biological environment and implanted materials. Actually, methods for biochemical factor delivery at the interface between implant surface and biological tissues are under investigation; a reliable technique is represented by the inclusion of biologically active molecules into biocompatible and biodegradable materials used for coating implant surface. This paper focuses the application of three polymeric materials already acknowledged in the clinical practice, i.e. poly-L-lactic acid (PLLA), poly-DL-lactic acid (PDLA), and sodium alginate hydrogel. They have been used to coat Ti (Ti2) and Ti6Al4V (Ti5) disks; their characteristics have been determined and their performances compared, with specific regard to the ability in allowing osteoblast adhesion in vitro. Moreover, profilometry data analysis permitted to identify a specific roughness parameter (peak density) which mainly controls the amount of osteoblast adhesion.