Morphologic and nanomechanical properties of tissue formed around bioactive sol-gel/ wollastonite coating on surgical grade stainless steel in dry and wet conditions

J. BALLARRE; R. SELTZER; E. MENDOZA; C. GARCÍA; Y-M. MAI; ANA LÍA CAVALIERI; S. CERÉ

Miami, US

Conferencia; Third International Conference on Mechanics of Biomaterials and Tissues; 2009

ICMOBT - Elsevier

Metallic materials are the most used materials in orthopedic or dental implants for their excellent mechanical properties. However they are not able to create a natural bonding with the mineralized bone and they could release metallic particles that could finally end in the removal of the implant [1, 2]. One way to avoid these effects is to protect the metallic implant with a biocompatible coating [3, 4] and also add bioactive particles to enhance implant fixation to the existing bone. Rapid improvements in the range of capabilities of Atomic Force Microscopy (AFM) now provide the opportunity to study the nanomechanics of materials as well as the morphology/topology[5]. AFM  associated to nanoindentation essays provides the means to study structure and/or morphology as well as the properties on both natural tissues and synthetic materials at resolutions down to the order of a nanometer [6]. With the aim of reproducing in a more accurate way the bone conditions, the AFM and nanoindentation experiments were carried out in simulated body fluid (SBF) solution environment [7]. In this work, samples coated with TEOS-MTES and 10% wt. of commercial wollastonite particles are implanted in Hokkaido tibiae rats. Transversal sections of the tibias samples are studied to characterize hydroxyapatite deposits and the composition of newly formed tissue arround the implant with AFM and nanoindentation experiments in dry and wet conditions. The results showed that the coatings promoted formation and growing of new bone in the periphery of the implant, both in contact with the old bone (remodellation zone) and in contact with the marrow. Comparing the AFM images and nanoindentation experiments in dry and wet conditions, these last ones seems to give similar results to cadaveric obtained values, making this a more correct method for bone analysis.