Over the last few decades, there is increasing worldwide concern over human health risks associated with extensive use of pesticides in agriculture. Developing excellent SERS substrate materials to achieve highly sensitive detection of pesticide residues in the food is very necessary owing to their serious threat to human health through food chains. Self -assembled metallic nanoparticles have been demonstrated to be excellent SERS substrate materials. Hence, alkanethiols-protected gold nanoparticles have been successfully prepared for forming larger -scale two-dimensional monolayer films. These films can be disassembled into a fluid state and reassembled back to crystallized structure by controlling surface pressure. Further investigations reveal that their self -assembled structures are mainly dependent on the diameter of gold nanoparticles and ligand length. These results suggest that the size ratio of nanoparticle diameter/ligand length within the range of 4.45 -2.35 facilitates the formation of highly ordered 2D arrays. Furthermore, these arrays present excellent SurfaceEnhanced Raman Scattering performances in the detection of trace thiram, which can cause environmental toxicity to the soil, water, animals and result in severe damage to human health. Therefore, the current study provides an effective way for preparing monodispersed hydrophobic gold nanoparticles and forming highly ordered 2D close -packed SERS substrate materials via self -assembly to detect pesticide residues in food. We believe that, our research provides not only advanced SERS substrate materials for excellent detection performance of thiram in food, but also novel fundamental understandings of self -assembly, manipulation of nanoparticle interactions, and controllable synthesis.

Due to their extensive use during and after the COVID-19 pandemic, many disposable face masks are irresponsibly deposited into the water environment, threatening the health of people living nearby. However, the effects of water conditions on the degradation and potential hazards of these masks are generally unclear. This paper entailed the release and cellular toxicity of micro/nano plastics from disposable face masks once discarded in different waters, including soil water, river water, and tap water, with deionized (DI) water as control. At first, polypropylene (PP) was confirmed to be the major component of disposable face masks with Raman and Fourier transform infrared (FTIR) techniques. To monitor the release rate of PP from masks, a silver nanoparticle (AgNP)-based surface-enhanced Raman scattering (SERS) method was established by employing the unique Raman fingerprint of PP at 2882 cm(-1). During 30-d incubation in different waters, the release rates of PP, sizes of PP aggregates, length of fibers, and proportions of plastics smaller than 100 nm were in the order of soil water > river water > tap water > DI water. All the obtained PP exhibited significant toxicity in human lung cancer (A549) cells at concentrations of 70 mg/L for 48 h, and the ones obtained in soil water exhibited the most severe damage. Overall, this paper revealed that environmental waters themselves would worsen the adverse effects of disposable face masks, and the key compounds affecting the degradation of masks remain to be clarified. Such information, along with the established methods, could be beneficial in assessing the health risks of disposable face masks in different waters.