Synergistic photothermal-magnetic nanoplatform: recyclable TEG-SPIONs for ultra-efficient pathogen elimination in medical wastewater

The proliferation of antibiotic-resistant bacteria (ARB) and pathogens in biomedical wastewater poses a critical global health threat, underscoring the need for antibiotic-free disinfection strategies. Herein, we develop recyclable triethylene glycol-modified superparamagnetic iron oxide nanoparticles (TEG-SPIONs) as an efficient photothermal antibacterial platform. Under near-infrared (NIR) irradiation, TEG-SPIONs exhibit outstanding photothermal performance with a conversion efficiency of 30.44%, enabling the rapid inactivation of bacteria through synergistic mechanisms, including membrane disruption, ROS generation, and nucleic acid leakage. Moreover, TEG-SPIONs effectively inhibit biofilm formation and disrupt mature biofilms. Their superparamagnetism allows facile magnetic retrieval and reuse, maintaining over 60% antibacterial activity after 20 cycles, along with excellent colloidal stability for 14 days. Unlike conventional antibiotics, TEG-SPIONs do not cause the development of resistance or secondary pollution. This work highlights the promise of TEG-SPIONs as a sustainable, recyclable nanoplatform for environmental remediation and water purification, offering a practical strategy against antimicrobial resistance.