Magneto-Photothermal Synergistic Hydrophobicity Nanoplatform for Efficient Enrichment and Ultrasensitive Detection of Micro-Nanoplastics

The persistent accumulation of micro-nanoplastics (MnPs) in aquatic environments poses serious ecological and health risks, but their efficient removal and detection remain challenging due to their diverse compositions and sizes. Here, we design a highly hydrophobic magnetic nanoplatform (Fe₃O₄@PDA-HDTMS, F@PH), characterized by low surface energy and multi-interaction adsorption, to effectively integrate multiple functions, including enrichment, removal, detection, and quantification of MnPs. The optimized platform effectively captured polyethylene (PE), polypropylene (PP), and polystyrene (PS) MnPs, achieving removal efficiencies of 93.8% for microplastics (MPs) and 87.2% for nanoplastics (NPs) in ultrapure water. It also maintained high performance in complex matrices, including tap water (84.3-85.8%), simulated seawater (73.2-76.3%), and tissue suspensions (67.8-71.0%). Coupled with a photoinduced microbubble-enhanced SERS (PMERS) platform strategy, F@PH generates microbubbles and thermocapillary flow, promoting the enrichment of MnPs onto silver nanoparticle (AgNP) substrates, which results in a 10²-fold signal enhancement compared to conventional SERS, allowing for ultrasensitive detection of MnPs. The detection limits reach 5 μg mL^-1 and 10 μg mL^-1 for 500 nm PE and PP MnPs, respectively. This integrated platform demonstrates high sensitivity and applicability in the analysis of bottled water and biological tissues, offering a promising approach for precise monitoring of MnPs and environmental remediation.