A team led by IMDEA Materials Institute and Universidad Politécnica de Madrid produced continuous nickel-titanium braided structures in a single laser powder bed fusion build. The open-access paper published on 30 September 2026 explores concepts for personalised transcatheter vascular devices including stents, valve frames and clot retrievers.

The study verifies that finished prototypes retained more than 90 percent elastic recovery after compression to 50 percent of their original diameter. Chronic outward force was up to five times lower than in the additive lattice structures examined. This is a mechanical proof of concept, not a clinical result: there is no in-vivo biocompatibility, animal or patient evidence yet.

Why print a braid instead of a lattice?

A conventional additively manufactured implant lattice deforms through bending of relatively rigid struts, so stiffness and local strain can rise sharply during severe compression. Braid filaments instead move relative to one another and change angle. The architecture can therefore absorb a large diameter change without concentrating every deformation at rigid nodes.

The algorithmic method maps lattice and woven geometry to anatomical surfaces with controllable fibre density, thickness, gaps and discontinuities. Printing a fully connected braid directly may avoid assembly from individual wires and enable patient-specific bifurcations or fenestrated devices.

LPBF does not deliver a finished implant

The as-built surface was too rough for the intended implant use. The team combined chemical etching and electropolishing, reducing fibre thickness by 47.7 percent and cross-sectional area by 71.1 percent. Finishing is therefore not cosmetic: it changes surface, geometry, stiffness and outward force together.

That creates a quality-control requirement. Designed, as-built and finished fibre dimensions need separate measurement; etching can over-thin local regions, particularly near extremities. Removal uniformity, NiTi composition, transformation temperature, surface nickel and corrosion state may all become release characteristics.

What the test established

The researchers assessed several prototypes with mechanical indicators and one compression–release cycle representing loading into and deployment from a catheter. The result shows that the design and manufacturing route can deliver large reversible deformation. It does not establish long-cycle fatigue, sustained pulsatile loading, corrosion ageing, performance after sterilisation or behaviour in physiological tissue.

Lower chronic outward force could in principle reduce vascular injury and thrombosis, but that remains a research interpretation. Comparative biological and eventually patient data are required for a clinical claim. Personalisation is likewise a geometric capability; the time and cost of imaging, design, manufacture, sterilisation and regulatory release remain open.

Next evidence

IMDEA names in-vitro biocompatibility and animal studies as prerequisites to clinical investigation. Neurovascular devices would require further miniaturisation; the authors mention two-photon polymerisation with metallic suspensions and magnetic functionalisation as possible research directions.

Editorial conclusion

The central advance is not simply another printed stent but translation of braid kinematics into a single connected LPBF geometry. Recovery above 90 percent and lower outward force are promising mechanical signals. Industrial and clinical value will depend on dimensional control through finishing, fatigue, biocompatibility and validation of the complete patient-specific workflow.

Sources

- npj Metamaterials: Additive manufacturing of superelastic NiTi braided metamaterials — peer-reviewed open research article, 30 September 2026. - IMDEA Materials Institute: Researchers develop 3D printing method… — primary institutional research release. - 3D Printing Industry: Woven in Metal — trade-press detector, 20 October 2026.