• The 2-micron-thick coating reduces the corrosion current density by 81% compared with prostheses without this treatment, whilst also reducing stiffness and improving implant-bone compatibility
• The research is being carried out by a multidisciplinary consortium comprising the CSIC and the Universities of Seville, Valladolid and the Polytechnic University of Catalonia

A research team from the Seville Institute of Materials Science (ICMS), a joint centre of the Spanish National Research Council (CSIC) and the University of Seville (US), has developed a new, more resistant and biocompatible coating for use on bone implants produced using 3D printers. The research has been published in the journal *Surface & Coatings Technology*.

The main innovation developed by the team has been the application of a nanometre-thick layer of a beta titanium alloy—containing niobium, zirconium and tantalum—onto so-called scaffolds. These 3D structures mimic the architecture of bone and serve as a support for the growth of bone tissue precursor cells.

This variant of titanium has mechanical properties that are more compatible with bone and significantly increases corrosion resistance in the biological environment. Specifically, using this layer, which is just 1–2 micrometres thick, the researchers have managed to reduce the corrosion current density by 81 per cent and decrease the perceived stiffness on the surface of the prosthesis. This behaviour results in improved biomechanical interaction with the bone, limiting the relaxation of the host tissue and promoting implant integration.

The coating was produced using the HiPiMS plasma technique, a variant of cathodic sputtering (also known as magnetron sputtering) in which energy is released in the form of high-intensity pulses to treat a sample or surface. Consequently, the resulting coating is characterised by a compact structure and a ‘rice grain’-like nanostructured morphology that not only acts as a chemical barrier but also enhances the implant’s biomechanical compatibility within the body.

For this reason, the CSIC’s technical contribution has been fundamental in overcoming the challenge of uniformly coating the porous geometries of the scaffolds, which are manufactured using 3D printing equipment (unique in terms of its performance) available at the UPC and within Professor Torres’s research group.

This breakthrough demonstrates that the integration of additive manufacturing (3D printing) and advanced surface engineering is an effective approach to developing safer and more durable customised prostheses. The collaboration between the ICMS and the participating universities highlights the potential of scientific cooperation to solve complex problems in the field of materials bioengineering.

Strategic partnership since 2023

The work was led by Juan Carlos Sánchez, a research scientist at the CSIC and head of the Tribology and Surface Protection (TRIPS) research group at the ICMS. The results build on a line of research coordinated by US professor Yadir Torres. This is complemented by the efforts of a multidisciplinary consortium in which the University of Valladolid (UVa) and the Polytechnic University of Catalonia (UPC) have also participated.

This research builds on a history of strategic collaboration that began in 2023, when the team validated the use of the HiPiMS technique for coatings made from a titanium, aluminium and vanadium alloy (Ti6Al4V), one of the most widely used in biomedicine. Subsequently, in 2025, the deposition of the beta titanium alloy (TNZT) onto solid titanium specimens was refined, achieving a reduction in surface stiffness of around 30 per cent. This facilitates a more natural transmission of loads to the bone, preventing bone loss around the implant. Indeed, this concept has been validated in this latest study, but in the complex three-dimensional geometries required for bone regeneration.

The next steps for the CSIC team are to continue applying coatings using the HiPIMS technique to implants with various shapes and complex geometries, with the aim of optimising the functionality between the biomaterial and the implant, thereby making them increasingly durable and resistant.

Reference:

Vilella, E.J. Delgado-Pujol, C. García-Hernández, G. Fargas, C.R.M. Afonso, D. Rodríguez, C. García-Cabezón, A. Alcudia, J.C. Sánchez-López, Y. Torres (2026). Engineering TNZT-coated titanium scaffolds via additive manufacturing and magnetron sputtering for bone tissue replacement. Surf. Coat. Technol. 522. https://doi.org/10.1016/j.surfcoat.2025.133128