Layer-by-Layer Assembly of Polystyrene/Ag for a Highly Reproducible SERS Substrate and Its Use for the Detection of Food Contaminants

Abstract

Polystyrene (PS) spheres were prepared through an emulsifier-free emulsion polymerization method, in which the reaction time, ionic strength, concentrations of copolymer were studied in detail. The resulting PS microspheres and Ag nanoparticles were used to construct a surface enhanced Raman scattering (SERS) substrate by a layer-by-layer assembly method. A relatively uniform distribution of PS/Ag in the films was obtained, and the multilayer substrate presented excellent SERS reproducibility and a tunable enhancement effect. The SERS substrate was used for detecting harmful pesticides (malachite green and dimetridazole) in food samples, with a limit of detection as low as 3.5 ppb. The obtained plasmonic composite has a promising future in the field of SERS sensing.

Exploring Deposition Techniques and Supramolecular Arrangement in Thin Films for Sensor Applications

“…The LbL technique allows the easy and controllable assembly of AuNPs and AgNPs on the optical fibre surface providing the LSPR signal (plasmon absorption band), which is sensitive to changes in the refractive index of the surrounding medium. Another optical sensing approach is centred on the fabrication of SERS substrates [187][188][189][190]. Highlights for the possibility of easily combining graphene and plasmonic particles uniting the fluorescence quenching of GO and signal enhancement from MNPs for SERS detection [188,189].…”

Application of two-dimensional layered materials in surface-enhanced Raman spectroscopy (SERS)

“…Chen et al 99 successfully synthesized a sophisticated RGO@MoS 2 @Ag ternary nanocomposite, and realized ultra-sensitive detection of low-concentration melamine solution, which would provide an effective guarantee for food safety. Zhang et al 100 prepared Polystyrene/Ag composites by layer-by-layer assembly which show excellent SERS performance. It can be used to detect harmful pesticides (malachite green and dimethylnitrozole) in food samples, with the LOD as low as 3.5 ppb.…”

Preparation of Plasmonic Ag@PS Composite via Seed-Mediated In Situ Growth Method and Application in SERS

“…In recent years, the plasmonic composite was developed and used in SERS sensing because the composite could enable additional enhancement or new function to the SERS substrate ( Sihan Zhang et al, 2021 ). The composite SERS substrates mainly include silicon, quartz, glass, copper, fibers, paper, swabs, eggshells, graphene oxide, and polymers ( Li et al, 2013 ; Tao et al, 2013 ; Gong et al, 2014 ; Kim and Min, 2014 ; Hou et al, 2015 ; Hu et al, 2015 ; Kong et al, 2015 ; Jin et al, 2016 ; Yaling et al, 2017 ; Zhang et al, 2019 ).…”