Magnetic AuNPs@TiO2@NF heterojunction for solar-light degradation of antibiotics and mitigation of bacterial resistance risk

Abstract

Antibiotic resistance is a silent crisis unfolding in slow motion, and sustainable solutions are urgently needed. We developed a solar-powered, magnetically recoverable Au@TiO₂@NF photocatalyst that degrades 91% of tigecycline in 33 minutes and eliminates its toxicity. The material's porous SiO₂-templated framework (53 m² g⁻¹) integrates plasmonic gold nanoparticles and magnetic nickel ferrite (NF), optimizing light absorption and recyclability. Structural analysis confirmed crystalline anatase TiO₂ and cubic NF phases, while electron microscopy revealed an interconnected porous network that enhances reactivity. Radical scavenger experiments identified superoxide radicals (˙O₂⁻) are the primary active species, with photogenerated holes and hydroxyl radicals (˙OH) playing complementary roles. This synergistic action is enhanced by our material's design: plasmonic gold injects hot electrons, while the tailored interface between TiO₂ and NF promotes efficient charge separation, yielding a 3.6-fold efficiency gain over TiO₂ alone. The catalyst is stable across a broad pH range (4.5–10) and is fully recovered post-reaction using a magnet, preventing secondary nanoparticle pollution. Degradation byproducts show no cytotoxicity in human fibroblasts, monocytes, or hepatocytes and reduce pro-inflammatory TNF-α by 40–60%. Crucially, it preserves CYP3A4 activity, avoiding drug-interaction risks. The material also functions as an electrochemical H₂O₂ sensor (LOD: 0.0447 mM), demonstrating multifunctionality. This work shows promise for antibiotic wastewater treatment. The solar-driven approach is efficient and environmentally safe.