Ti-based superelastic & biocompatible alloy coatings for medical devices – Super-Rev

The Super-Rev project aims at developing novel bio-functional Ni-free Ti-based coatings which will fulfil specific and practical requirements for their applicability on biomedical implantable devices in order to circumvent the allergenic and possible toxic effects of Ni ions released from the Nitinol implant into the surrounding body fluids and living tissues. Quaternary Ti-Nb-based alloys incorporating ß-stabilizing and fully biocompatible elements (Nb, Zr, Mo, Hf, Sn) will be synthesized by magnetron sputtering on different substrates, with the ultimate goal to coat guidewires and staples made of Nitinol.
These novel coatings must satisfy both excellent biocompatibility and biomechanical requirements, in particular their ability to manifest similar mechanical properties to those of Nitinol, i.e., superelastic recovery and low elastic modulus, in order to establish a mechanical continuum with Nitinol base system over the entire period of service in the body without any failure. The mechanical (adhesion, wear and fatigue resistance), functional (superelasticity) and biological (cytotoxicity and hemocompatibility, biocorrosion resistance and cell responses) properties of coated Nitinol devices will be systematically evaluated and compared with existing non-coated Nitinol devices.
The Super-Rev project is multidisciplinary and the present consortium offers a unique opportunity to capitalize on a common research strategy in the covered field by utilizing each partner’s expertise, from physical-chemistry metallurgy, thin film mechanical properties and biology. This complementary expertise puts us in a position to break new avenues in bio-functional coatings that exhibit both superelastic properties and biocompatibility in simulated body fluids conditions. This project, which relies on an innovative integrated approach, from manufacturing to functionalities, has an applicative character in line with the expectations of the Défi “Stimuler le renouveau industriel”, by specifically addressing the topical Axis “Matériaux métalliques et inorganiques et procédés associés” in terms of surface functionalization. Besides this technological achievement, the Super-Rev project will also address scientific questions thanks to the implementation of unique in situ experiments (stress monitoring during growth, XRD and TEM characterization during mechanical loading), enabling to get insights on the influence of alloy chemistry, microstructure and stress state on the functional properties.