Flexible PET/ITO/Ag SERS Platform for Label-Free Detection of Pesticides

Abstract

We show a new type of elastic surface-enhanced Raman spectroscopy (SERS) platform made of poly(ethylene terephthalate) (PET) covered with a layer of indium tin oxide (ITO). This composite is subjected to dielectric barrier discharge (DBD) that develops the active surface of the PET/ITO foil. To enhance the Raman signal, a modified composite was covered with a thin layer of silver using the physical vapor deposition (PVD) technique. The SERS platform was used for measurements of para-mercaptobenzoic acid (p-MBA) and popular pesticides, i.e., Thiram and Carbaryl. The detection and identification of pesticides on the surface of fruits and vegetables is a crucial issue due to extensive use of those chemical substances for plant fungicide and insecticide protection. Therefore, the developed PET/ITO/Ag SERS platform was dedicated to quantitative analysis of selected pesticides, i.e., Thiram and Carbaryl from fruits. The presented SERS platform exhibits excellent enhancement and reproducibility of the Raman signal, which enables the trace analysis of these pesticides in the range up to their maximum residues limit. Based on the constructed calibration curves, the pesticide concentrations from the skin of apples was estimated as 2.5 µg/mL and 0.012 µg/mL for Thiram and Carbaryl, respectively. Additionally, the PET/ITO/Ag SERS platform satisfies other spectroscopic properties required for trace pesticide analysis e.g., ease, cost-effective method of preparation, and specially designed physical properties, especially flexibility and transparency, that broaden the sampling versatility to irregular surfaces.

Fabrication of Bioprobe Self-Assembled on Au–Te Nanoworm Structure for SERS Biosensor

“…To calculate the EF of the Au–Te nanoworm, the ratio of SERS to the normal Raman spectrum (NRS) of methylene blue was determined using the following equation [ 39 , 40 ]. The laser was irradiated at 785 nm and compared to the intensity at 495 cm −1 , where the methylene blue peak was apparent as shown in Figure 3 .…”

Advances in the Detection of Dithiocarbamate Fungicides: Opportunities for Biosensors

“…Still, the total amount of the S−C−S group in the fungicide mixture was correlated with I 0.5 , where I is the intensity of the SERS signal at 1382 cm −1 . Other recently published papers related to the detection DTFs usually work with thiram as probe analyte using a variety of silver nanomaterials for the SERS effect [ 22 , 23 , 24 ].…”

Recyclable SERS-Based Immunoassay Guided by Photocatalytic Performance of Fe3O4@TiO2@Au Nanocomposites

“…Therefore, to impede this pressing trend, it is essential to realize the early diagnosis and therapeutics of prostate cancer for which prostate specific antigen (PSA) has been the most extensively applied directional tumor marker [3]. Surface-enhanced Raman scattering (SERS) technique has attracted wide interest as a method extensively utilized in the field of labeled immunoassay for monitoring specific cancer antigens, mainly due to a number of advantages such as good spectral selectivity, no self-quenching and photobleaching, higher sensitivity, and multicomponent detection ability [4][5][6][7][8][9][10]. Accordingly, the ultrasensitive SERS-based immunoassays, which are formed of immune probe, target antigen, and antibody-immobilized substrate, have been built on the basis of representative sandwich immune structures [11][12][13].…”