Nitric oxide‑releasing porous titanium foams fabricated by scalable sintering-dissolution process for antibiofilm...

Orthopaedic implants require surfaces that resist bacterial colonisation while supporting host cell compatibility. In this study, we fabricated highly interconnected porous titanium (Ti) foams using a cost‑effective sintering-dissolution process (SDP) and functionalised them with 11‑aminoundecyltriethoxysilane (AUTES) and covalently tethered N-diazeniumdiolate nitric oxide (NO) donors. Structural characterisation by Scanning electron microscopy, X‑ray micro‑CT, and Brunauer-Emmett-Teller analyses confirmed a hierarchical porous architecture with ~ 73% total porosity and extensive internal surface area, enabling efficient chemical functionalisation. Chemiluminescence analysis demonstrated formulation‑dependent NO payloads and sustained release for over 15 h in bacterial culture medium. The NO‑releasing foams significantly reduced biofilm-associated Escherichia coli and Staphylococcus aureus compared with untreated controls, with the 20% AUTES/NO formulation showing the most persistent antibiofilm activity at 24 h (p < 0.05). Limited effects were observed against planktonic bacteria. Human mesenchymal stem cells (hMSCs) adhered to and remained viable on both unmodified and functionalised foams over 7 days, indicating cytocompatibility of the surface modification following NO release. These findings demonstrate that SDP-derived porous Ti foams can be functionalised for localised NO delivery and effective antibiofilm activity while maintaining initial hMSC compatibility, offering a scalable platform for multifunctional Ti-based implant surfaces.