Polymer multilayers enabled stable and flexible Au@Ag nanoparticle array for nondestructive SERS detection of pesticide residues.

The development of flexible and robust plasmonic substrates has become a hot research topic in simplifying and extending the application of surface-enhanced Raman scattering (SERS) technique for real-world analysis. In this work, a facile method to fabricate an Au@Ag nanoparticle array sandwiched between the adhesive acrylic polymer tape and polyethene terephthalate (PET) film (T/Au@Ag/PET) as a high-performance SERS chip was reported for nondestructive detection of thiram on fruit peels. For this SERS chip, the ordered Au@Ag nanoparticle array formed by the self-assembly method was closely-packed, which generated high-density sub-3-nm gaps and could produce high reproducible and sensitive SERS enhancement effects. The measurement of crystal violet with the limit of detection of 7.24 × 10-10 M was realized by targeting Raman shift at 1177 cm-1. Moreover, the excellent flexible feature of acrylic polymer tape enabled the substrate to withstand a tensile strain value of 20% for three cycles without significantly losing its SERS activity. By covering with a PET film, the SERS chip could maintain 87% SERS activity after storage for 60 days in the air environment, and could well withstand the influence of harsh conditions such as high temperature and ultrasound treatments. As a proof of the concept, the SERS tape was directly used to detect thiram on apple, tomato, and cucumber peels via a simple sampling-and-detection procedure, and the detection limit of 5 ng/cm2 was achieved. The T/Au@Ag/PET SERS chip should hold a promising candidate for food safety analysis in the future.

Wang K ，Sun DW ，Pu H ，Wei Q ... -  《-》

Stable, Flexible, and High-Performance SERS Chip Enabled by a Ternary Film-Packaged Plasmonic Nanoparticle Array.

Wang K ，Sun DW ，Pu H ，Wei Q ，Huang L ... -  《-》

Plasmonic 3D Semiconductor-Metal Nanopore Arrays for Reliable Surface-Enhanced Raman Scattering Detection and In-Site Catalytic Reaction Monitoring.

Zhang M ，Chen T ，Liu Y ，Zhang J ，Sun H ，Yang J ，Zhu J ，Liu J ，Wu Y ... -  《ACS Sensors》

Rapid nondestructive detection of mixed pesticides residues on fruit surface using SERS combined with self-modeling mixture analysis method.

Mixed pesticides are usually applied to agricultural products to enhance agricultural production. However, their presence in the environment and food poses serious health risks to humans. Therefore, rapid and reliable detection methods for mixed pesticides residues are in need to minimize potential health hazards. Herein, a nondestructive and sensitive strategy was developed to determine thiram and thiabendazole (TBZ) mixture on fruit surface using surface-enhanced Raman spectroscopy (SERS) technology coupled with interfacial self-assembly gold nanorods (Au NRs) array substrates together with self-modelling mixture analysis (SMA) method. Firstly, a large area high-density Au NRs array was fabricated by organic-aqueous interfacial self-assembly to serve as a sensitive SERS substrate for simultaneously screening of thiram and TBZ on the fruit surface. Then, an SMA method was employed to identify and separate the Raman spectrum for each pesticide from the Raman spectra of the pesticides mixture on the contaminated fruit surface. Results showed that using SERS technique with the SMA method, qualitative and quantitative analyses of a single component from the spectra of the mixture were simultaneously realized, and the resolved pure spectrum of each pesticide was presented. The limits of detection (LOD) of pesticides on the surface of apple, tomato and pear were 0.041, 0.029 and 0.047 ng/cm2 for thiram, and 0.79, 0.76 and 0.80 ng/cm2 for TBZ, respectively. It was anticipated that the proposed SERS detection approach combined with SMA methods should pave the way for detecting multi-analytes in practical applications for agriculture and food safety inspection.

Hu B ，Sun DW ，Pu H ，Wei Q ... -  《-》

Flexible and transparent Surface Enhanced Raman Scattering (SERS)-Active Ag NPs/PDMS composites for in-situ detection of food contaminants.

The fabrication of flexible and transparent Surface Enhanced Raman Scattering (SERS) substrates enabling fast, sensitive and on site detection is relevant for the practical application of SERS for real world analysis, such as food safety and organic pollutants monitoring. In this work novel Ag NPs/PDMS composites were fabricated and employed for the SERS detection of food contaminants directly on food surfaces. Ag NPs/PDMS composites were obtained by self-assembly of organic Ag nanoparticle solutions on flexible PDMS surfaces. Preliminary evaluation of the suitability of Ag NPs/PDMS probes for SERS analysis showed that composites were characterized by a SERS enhancement factor (EF) of 3.1 × 105, good stability and resistance to harsh conditions as well as good uniformity and batch to bach reproducibility. The "sticky" nature of Ag NPs/PDMS composites was exploited to "paste" them on irregular analytical surfaces, thus enabling the detection in situ of food contaminant crystal violet (CV) and pesticide thiram, respectively. Specifically, CV and thiram concentrations as low as 1 × 10-7 M and 1 × 10-5 M were measured on contaminated fish skin and orange peel, respectively. Furthermore, efficient SERS detection by micro-extraction of CV from fish skin and thiram from fruit surfaces was achieved, showing the analytical versatility of the fabricated SERS composites.

Alyami A ，Quinn AJ ，Iacopino D 《-》