Glucose-activated enzyme-nanozyme cascade nanoflowers for antibacterial surfaces on cement mortar

Bacterial contamination and biofilm formation on material surfaces remain major challenges in aqueous environments. Herein, we report a glucose-activated antibacterial cement surface created by immobilizing enzyme-nanozyme cascade nanoflowers composed of glucose oxidase and copper phosphate (GOx-Cu NFs) onto cement mortar. In this system, glucose oxidase catalyzes glucose oxidation to generate hydrogen peroxide (H₂O₂), which is subsequently converted into reactive oxygen species through the peroxidase-like catalytic activity of the Cu-based nanoflowers, enabling efficient antibacterial activity. The GOx-Cu NFs exhibited strong bactericidal performance, achieving 99.9% killing of the Gram-positive bacterium Staphylococcus aureus and the Gram-negative sulfate-oxidizing bacterium Thiobacillus novellus at concentrations as low as 0.030 mg mL^-1 and 0.015 mg mL^-1, respectively, at an initial bacterial density of 10⁴ CFU mL^-1. Importantly, the nanoflowers could be successfully immobilized onto cement mortar surfaces, where clear inhibition zones of 6.23 ± 2.77 mm for S. aureus and 5.78 ± 2.95 mm for T. novellus were observed. The immobilized nanoflowers retained antibacterial functionality under aqueous storage conditions for at least 15 days. These results demonstrate a practical strategy for engineering reactive antibacterial cement surfaces and highlight the potential of enzyme-nanozyme hybrid nanoflowers as antibacterial coatings for solid materials exposed to aqueous environments.