Josefina Ballarre

In vivo and in vitro evaluation of vitreous coatings on cobalt base alloys for prosthetic devices

Abstract This work describes the electrochemical and biological response of wires of CrCoMo surgical alloys (F75) covered by two layers of SiO2 coating prepared by sol–gel to evaluate their properties in simulated body fluids and implanted in Lew rats for the in vivo evaluation. Wires were coated by a single layer of hybrid silica (that means that the coating contains Si–CH3 groups) covered by another similar layer containing a suspension of bioactive glass-ceramic particles in the system CaO–SiO2–P2O5 to provide fixation to bone. Standard electrochemical tests were conducted for the in vitro measurements and showed smaller current density for the covered samples than for the uncovered ones after 30 days of immersion. For the in vivo tests the coated wires were inserted in the tibia cortical bone by a press fit technique in Lew rats and analysed after 53 days of being implanted. We observed that none of the wires created an inflammatory response. Moreover the covered wires developed neo formed bone in the surroundings of the samples made of collagen with a vascular development. Uncovered wires did not develop new histionic structure.

Enhancing low cost stainless steel implants: bioactive silica-based sol-gel coatings with wollastonite particles

A hybrid organic-inorganic sol-gel coating with the addition of wollastonite particles is used as a potential solution to improve performance of low cost AISI 316L stainless steel. This work is focused on characterising the coatings by studying their synthesis and deposition, electrochemical, and in vitro and in vivo response. The coated implants presented in vitro Ca/P-rich apatitic precursors phases on their surface and acceptable electrochemical behaviour. The in vivo response regarding bone formation seems to be excellent either with the implant in contact with bone marrow, in contact with the endostium or in contact with the trabecular bone. The bioactive and regenerative responses of bone tissue to the TEOS-MTES-wollastonite system over-compensate the coating deterioration reaction, making these coatings as a good way to improve osseo-integration of stainless steel for long term use implants.

Coatings Containing Silica Nanoparticles and Glass Ceramic Particles Applied onto Surgical Grade Stainless Steel

Metals are the most used materials as orthopaedic 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. A promising alternative to avoid those effects is to protect the implant with a biocompatible coating. In this work there are analyzed two kinds of protective organic-inorganic coatings made by sol gel technique with the adding of silica particles, in order to increase the barrier effect of the coating, and glass-ceramic (GC) particles with the aim of generating bioactivity. X-ray photoelectron spectroscopy (XPS) and electrochemical techniques were used to analyze the bioactive and protective response of this silica reinforced coatings with the adding GC particles applied on surgical grade stainless steel.

In vitro and in vivo characterization of anodised zirconium as a potential material for biomedical applications

In vitro studies offer the insights for the understanding of the mechanisms at the tissue-implant interface that will provide an effective functioning in vivo. The good biocompatibility of zirconium makes a good candidate for biomedical applications and the attractive in vivo performance is mainly due to the presence of a protective oxide layer. The aim of this study is to evaluate by in vitro and in vivo approach, the influence of surface modification achieved by anodisation at 30 and 60V on zirconium implants on the first steps of the osseointegration process. In this study cell attachment, proliferation and morphology of mouse myoblast C2C12-GFP and in mouse osteoprogenitor MC3T3-E1 cells was evaluated. Also, together with the immune system response, osteoclast differentiation and morphology with RAW 264.7 murine cell line were analysed. It was found that anodisation treatment at 60V enhanced cell spreading and the osteoblastic and osteoclastic cells morphology, showing a strong dependence on the surface characteristics. In vivo tests were performed in a rat femur osteotomy model. Dynamical and static histological and histomorphometric analyses were developed 15 and 30days after surgery. Newly formed bone around Zr60V implants showed a continuous newly compact and homogeneous bone just 15 after surgery, as judged by the enhanced thickness and mineralization rate. The results indicate that anodising treatment at 60V could be an effective improvement in the osseointegration of zirconium by stimulating adhesion, proliferation, morphology, new bone thickness and bone mineral apposition, making zirconium an emerging candidate material for biomedical applications.

Anodisation and Sol–Gel Coatings as Surface Modification to Promote Osseointegration in Metallic Prosthesis

Orthopaedic devices for permanent implants require short term fixation and fast bone attachment and healing. Superficial modification of surgical implants is often used as a tool to generate a surface that besides being protective could also allow the integration of the metal to the human body, creating a “bioactive” surface that has the ability of creating a natural bonding between the metal surface and the existing bone. One way of achieving this surface modification is by means anodisation since an increase in the thickness and changes in the topography of the native oxide formed on metals can produce an improvement in bone response. Other possibility in the surface modification of the metallic implants is the coatings with organic-inorganic ceramic or glassy coatings as a way to improve the implant performance.The aim of this charter is review the surface modifications produced on orthopaedic and dentistry metallic materials by anodisation and by hybrid coatings by sol gel technique with the aim of promoting both corrosion resistance in physiological fluids and bioactivity.

Bioactive Silica Based Coating on Stainless Steel Implants

Fil: Ballarre, Josefina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnologia de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingenieria. Instituto de Investigaciones en Ciencia y Tecnologia de Materiales; Argentina

Processing of microCT implant-bone systems images using Fuzzy Mathematical Morphology

Fil: Bouchet, Agustina. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina. Universidad Nacional de Mar del Plata; Argentina

Characterization and quantification of oxides generated by anodization on titanium for implantation purposes

The use of titanium as implant material is widely known in the surgery field. The formation of natural or artificial compact and protective oxide is a convenient tool for metal protection and a good way to generate phosphate deposits to enhance biocompatibility and bone fixation with the existing tissue. The present work has the aim of superficially modify commercially pure titanium sheets used in orthopedics and odontology, with a potencistatic anodization process with an ammonium phosphate and ammonium fluoride solution as electrolyte. The objective is to generate titanium oxides doped with phosphorous on the surface, to promote bioactivity. The characterization and quantification of the generated deposits is presented as a starting point for the future application of these materials. The applied characterization methods are X ray diffraction, micro-Raman spectroscopy analysis for evaluating the chemical and phase composition on the modified surface and PDI image analysis techniques that allow the segmentation of SEM images and the measurement and quantification of the oxides generated by the anodization process. The samples with polished treated surface at 30V have the deposit of a phosphate rich thick layer covering almost all the surface and spherical-shaped titanium oxide crystals randomly placed (covering more than 20% of the surface area). .