Synergistic SERS effects in organic/MoS₂ heterojunctions with cavity structure enabling nanoplastics screening and antibiotic adsorption behavior detection

The detection of nanoplastics (NPs) and their interactions with antibiotics is critical due to their potential environmental and health risks. Traditional detection methods are challenged by the small size and chemical similarity of NPs to microplastics. Current surface-enhanced Raman scattering (SERS) substrates for NP detection are limited by high cost, reliance on single enhancement modes, and insufficient sensitivity and selectivity, especially for NP-antibiotic complexes. In this study, the F/M-AAO substrate, which integrates 2,3,5,6-tetrafluoro-tetracyanoquinodimethane (F₄TCNQ) and molybdenum disulfide (MoS₂) with anodic aluminum oxide (AAO) templates, is used to enhance the detection of NPs and NP-antibiotic complexes. The conical cavity structure of the substrate facilitates the enrichment and direct detection of NPs with diameters smaller than 450 nm. The three-dimensional (3D) F/M-AAO substrate achieved a limit of detection (LOD) of 1.73 × 10⁶ ng/L for 100-nm NPs and a minimum detection concentration of 10⁻¹⁰ M for ciprofloxacin adsorbed on NPs (NPs-CIP). It demonstrated remarkable sensitivity and selectivity in the detection of both individual NPs and NP-antibiotic complexes. This work highlights the innovative application of the F/M-AAO substrate in the SERS detection of NPs and NP-antibiotic complexes, providing a low-cost and effective platform for monitoring emerging environmental contaminants.