Nitric Oxide‐Generating Poly (allylamine hydrochloride) Coating on Biomedical Titanium Implant

ABSTRACT Titanium (Ti) and its alloys are widely used in biomedical implants for their mechanical strength, biocompatibility, and corrosion resistance. However, inflammation and infection at the tissue‐implant interface can compromise long‐term function. Local nitric oxide (NO) delivery via donor‐loaded coatings can address both challenges, but they suffer from burst release and reservoir depletion. Here, we report a NO‐generating coating in which poly(allylamine hydrochloride) (PAH) is covalently immobilized onto NaOH‐treated Ti via 6‐phosphonohexanoic acid. In solution, PAH catalyzed NO release from S ‐nitrosoglutathione (GSNO; 50 µ m ) with dose‐dependent output reaching 30.75 ± 0.76 µ m after 6 h. When immobilized, the PAH‐coated Ti generated cumulative NO of 22.42 ± 2.14 µ m over 24 h. NO generation increased linearly before plateauing and scaled with GSNO and PAH content. The coating retained activity over five reuse cycles and remained functional after exposures to pH 5 and 8.5, while extreme pH (3 or 12) diminished performance. Human umbilical vein endothelial cells maintained >95% viability upon exposure to PAH‐coated Ti, with elevated intracellular NO, increased IL‐10 expression, and reduced NF‐κB activation and TNF‐α expression, indicating an immunomodulatory response. This approach enables recyclable, on‐demand NO generation while preserving endothelial compatibility.