03458nas a2200409 a 4500 20260818090121.0 230203s2022 th a ||| 000 eng d .b12398275 AIT Thesis no.ISE-22-10 Napatsakorn Kamkrua Design and fabrication of aptamer-based SERS chips for selective detection of paraquat herbicide residues in water and soil Pathum Thani : Asian Institute of Technology, 2022 71 p. : ill. Thesis ; no. ISE-22-10 Thesis (M. Eng.) - Asian Institute of Technology, 2022 A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Nanotechnology A common herbicide such as paraquat has been countlessly applied in agriculture, and its residues are left in water and soil. Paraquat toxicity highly damages the body, which can be lethal in a later stage. Thus, paraquat detection is important and several techniques have been developed in recent years. Raman spectroscopy facilitates herbicide detection in rapid and non-destructive ways. Furthermore, surface-enhanced Raman spectroscopy (SERS) and bioreceptors are commonly utilized to enhance the sensitivity and selectivity of molecular structure detection, respectively. This study focuses on optimizing SERS-active substrates to improve the selectivity and rapidity of paraquat detection. This work also aimed to develop the combinations of SERS and biosensors for paraquat detection by functionalizing metallic nanostructures with an aptamer that is specific to the paraquat molecule via Raman spectroscopy. Soil and water samples were used for the evaluation of optimized SERS-active substrates. The sensitivity, selectivity, and limit of detection were investigated by Raman measurement. This study optimized the ONSPEC-Prime SERS chip (AgNRs) for paraquat detection in water and soil samples. Without extraction protocol, the chip provided a sensitivity of 638.96 a.u./æM and a detection limit (LOD) of 0.1 æM for the water sample. However, in the soil samples, paraquat extraction protocol with alumina absorbent is required. Furthermore, the aptamer-based SERS chip was successfully fabricated with a sensitivity of 609.15 a.u./æM and LOD of 0.35 æM using 0.1 æM of aptamer immobilized on the ONSPEC-Lite SERS chip (AuNPs). Raman spectroscopy Biosensors Bora, Tanujjal, Chairperson Noppadon Nuntawong, Co-Chairperson Ricco, Raffaele, Examination committee Loc Thai Nguyen, Examination committee Royal Thai Government Scholarships , Scholarship Donor Asian Institute of Technology. Thesis ; no. ISE-22-10 Full-Text http://203.159.5.9/ait-thesis/detail.php?q=B18184 .b12398275 mnait m 250411 0 230203 m a m 0 mnarc mnarc 67 40 Barcode : - CREATED : 2023-01-02 RECORD # : i13429000 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : 30050121041668 CREATED : 2023-02-13 RECORD # : i13432096 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 26932 26932 0 0 0 0 MAIN MAIN mnarc 2026-08-18 0 AIT Thesis no.ISE-22-10 2026-08-18 09:01:21 2026-08-18 67 0 0 0 0 MAIN MAIN mnarc 2026-08-18 0 AIT Thesis no.ISE-22-10 30050121041668 2026-08-18 09:01:22 1 2026-08-18 40