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Portacomaro, Italy

Verne E.,Polytechnic University of Turin | Ferraris S.,Polytechnic University of Turin | Cassinelli C.,NobilBio Ricerche | Boccaccini A.R.,Friedrich - Alexander - University, Erlangen - Nuremberg
Surface and Coatings Technology | Year: 2015

Bioglass® type 45S5 is the most widespread bioactive glass studied for its inorganic bioactivity and ability to affect cell behaviour. In this research work sintered Bioglass® substrates were functionalized with a biological molecule (the enzyme alkaline phosphatase - ALP) in order to couple bioactive glass typical inorganic properties with biological signals. For the first time ALP grafting has been performed on the standard Bioglass® composition, which is the most widely bioactive glass studied and currently commercialized in various forms. ALP was grafted to sintered Bioglass® glass-ceramic pellets both via silanization and via direct bonding to hydroxyl groups exposed on the surface. The presence of the biomolecule was investigated by means of XPS and its activity by enzymatic activity test. In vitro bioactivity of sintered Bioglass® at different steps of the functionalization process was investigated by soaking samples in simulated body fluid (SBF) for various experimental times.The possibility to graft ALP in an active state on sintered Bioglass® samples both via direct grafting and silanization routes has been demonstrated in the present research. ALP enhances and fastens in vitro bioactivity of the glass-ceramic. Surface functionalization of Bioglass® pellets is of interest as model for sintered Bioglass® derived scaffolds to be used in bone engineering. © 2015 Elsevier B.V.

Spriano S.,Polytechnic University of Turin | Ferraris S.,Polytechnic University of Turin | Ferraris S.,Bionica Technology S.r.l | Pan G.,Polytechnic University of Turin | And 3 more authors.
Journal of Mechanics in Medicine and Biology | Year: 2015

A proper stimulation of the cell activity is the last request to the new biomaterials, intended for bone substitution and osseointegration. In this regard, the scientific literature suggests that the surface modification on a nanoscale is a major source of innovation. The nano features and multiscale topographies can stimulate cell differentiation and activity. Moreover, the presence of specific biological molecules grafted onto the biosurfaces can properly stimulate cells to tissue regeneration. The final aim is to promote a fast and physiological bone healing, at the implant site. In order to be suitable for implantation, the modified surfaces must sustain the implantation and working load/friction without damages. Two different innovative surface modifications of the Ti6Al4V alloy were tested in this research. The first one is an inorganic modification and it is aimed at inducing in vivo apatite precipitation (inorganic bioactivity) and cell interaction through nano features. The modified surface shows a complex topography (micro and nanoroughness), a modified surface chemistry (high density of hydroxyls groups), high wettability and protein absorption. Moreover, an additional biological modification by grafting of alkaline phosphatase (ALP) was tested. The modified surfaces were compared with the traditional polished and blasted ones, in terms of osteoblast adhesion, proliferation and morphology. A significant increase in the cell proliferation rate was observed on the modified materials. Moreover, the osteoblasts showed a more differentiated aspect and filopodia exploring the nanotextures on both the treated materials. © 2015 World Scientific Publishing Company.

Ferraris S.,Polytechnic University of Turin | Vitale A.,Polytechnic University of Turin | Bertone E.,Polytechnic University of Turin | Guastella S.,Polytechnic University of Turin | And 3 more authors.
Materials Science and Engineering C | Year: 2016

The objects of this research are commercially pure titanium surfaces, with multifunctional behavior, obtained through a chemical treatment and biological functionalization. The explored surfaces are of interest for dental implants, in contact with bone, where several simultaneous and synergistic actions are needed, in order to get a fast and effective osseointegration. The here described modified surfaces present a layer of titanium oxide, thicker than the native one, with a multi-scale surface topography (a surface roughness on the nano scale, which can be overlapped to a micro or macro roughness of the substrate) and a high density of OH groups, that increase surface wettability, induce a bioactive behavior (hydroxyapatite precipitation in simulated body fluid) and make possible the grafting of biomolecules (alkaline phosphatase, ALP, in the present research). The surface oxide is an efficient barrier against corrosion, with passive behavior both with and without application of an external voltage. © 2015 Elsevier B.V.

Ferraris S.,Polytechnic University of Turin | Vitale-Brovarone C.,Polytechnic University of Turin | Bretcanu O.,Polytechnic University of Turin | Bretcanu O.,Newcastle University | And 2 more authors.
Applied Surface Science | Year: 2013

Bone reconstruction after tissue loosening due to traumatic, pathological or surgical causes is in increasing demand. 3D scaffolds are a widely studied solution for supporting new bone growth. Bioactive glass-ceramic porous materials can offer a three-dimensional structure that is able to chemically bond to bone. The ability to surface modify these devices by grafting biologically active molecules represents a challenge, with the aim of stimulating physiological bone regeneration with both inorganic and organic signals. In this research work glass ceramic scaffolds with very high mechanical properties and moderate bioactivity have been functionalized with the enzyme alkaline phosphatase (ALP). The material surface was activated in order to expose hydroxyl groups. The activated surface was further grafted with ALP both via silanization and also via direct grafting to the surface active hydroxyl groups. Enzymatic activity of grafted samples were measured by means of UV-vis spectroscopy before and after ultrasonic washing in TRIS-HCl buffer solution. In vitro inorganic bioactivity was investigated by soaking the scaffolds after the different steps of functionalization in a simulated body fluid (SBF). SEM observations allowed the monitoring of the scaffold morphology and surface chemical composition after soaking in SBF. The presence of ALP enhanced the in vitro inorganic bioactivity of the tested material. © 2013 Elsevier B.V.

Ferraris S.,Polytechnic University of Turin | Spriano S.,Polytechnic University of Turin | Bianchi C.L.,University of Milan | Cassinelli C.,NobilBio Ricerche | Verne E.,Polytechnic University of Turin
Journal of Materials Science: Materials in Medicine | Year: 2011

Titanium and its alloys are the most widespread materials for the realization of orthopaedic and dental implants due to their good mechanical properties and biocompatibility. Surface functionalization of biomaterials aimed to improve and quicken implant integration and tissue regeneration is an active research field. The opportunity to confer biological activity (ability to directly stimulate cells with proper biological signals) to the Ti6Al4 V alloy, previously modified to be bioactive from the inorganic point of view (apatite precipitation), was explored in this research work. The alkaline phosphatase (ALP) enzyme was grafted to metal surface via tresyl chloride activation, maintaining its activity. A synergistic effect between biological functionalization and inorganic bioactivity was observed. © 2011 Springer Science+Business Media, LLC.

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