Evaluation of Silicon Dioxide–Based Coating Enriched with Bioactive Peptides Mapped on Human Vitronectin and Fibronectin: In Vitro and In Vivo Assays MONICA DETTIN, 1 ANDREA BAGNO, 1 MARGHERITA MORPURGO, 2 ANTONIO CACCHIOLI, 3 MARIA TERESA CONCONI, 2 CARLO DI BELLO, 1 CARLO GABBI, 3 ROBERTA GAMBARETTO, 1 PIER PAOLO PARNIGOTTO, 2 SARA PIZZINATO, 4 FRANCESCA RAVANETTI, 3 and MASSIMO GUGLIELMI 4 ABSTRACT A wide range of biochemical signals promoting cell functions (adhesion, migration, proliferation, and dif- ferentiation) and thereby improving the osseointegration process are currently investigated. Unfortunately, their application for the production of bioactive implantable devices is often hampered by their insolubility; instability; and limited availability of a large amount of inexpensive, high-purity samples. An attractive alternative is the use of short peptides carrying the minimum active sequence of the natural factors. Synthetic peptides mapped on fibronectin and vitronectin have been demonstrated to enhance cell adhesion both to polystyrene and acellular bone matrix; in particular, a nonapeptide sequence from human vitronectin works via an osteoblast-specific adhesion mechanism. In this study, we incorporated these peptides into a sol-gel silica dressing applied to coat sand-blasted and acid-attacked titanium samples; measured the kinetic of peptide release; and used titanium disks, coated with a peptide-enriched film, as substrates to determine the peptide concentration that maximizes cell adhesion in vitro. We also evaluated in vivo the capacity of the vitronectin-derived peptide to improve osteo- genic activity: histologic analysis revealed markedly improved osteogenic activity around peptide-enriched samples. This article also discusses the role of surface characteristics and the importance of bioactive peptides. INTRODUCTION T HE CLINICAL SUCCESS of an endosseous artificial implant is largely related to the quality of its ‘‘osseointegra- tion,’’ namely the level of direct structural and functional connection with the surrounding living bone. Osseointe- gration is achieved through a sequence of events that occur mainly at the interface between the implant and the biolo- gical environment, and it is known to imply both implant anatomic congruency and load-bearing capacity. 1–4 Because of the importance of surface phenomena in the integration process, any strategy that aims at improving implantable devices should be based on the promotion of beneficial in- teractions at the interface between biomaterial and tissue in vivo. The improvement of interface phenomena is now based on the optimization of both surface morphology and material chemistry. From a morphologic point of view, it has been stated that surface characteristics control the osseointegration process. Indeed, cytoskeleton activity and cellular motility 1 Department of Chemical Process Engineering, University of Padova, Padova, Italy. 2 Department of Pharmaceutical Sciences, University of Padova, Padova, Italy. 3 Department of Animal Health, University of Parma, Parma, Italy. 4 Department of Mechanical Engineering, University of Padova, Padova, Italy. TISSUE ENGINEERING Volume 12, Number 12, 2006 # Mary Ann Liebert, Inc. 3509