Plasmonic Ag Nanoparticles: Correlating Nanofabrication and Aggregation for SERS Detection of Thiabendazole Pesticide

Author(s)

Oliveira, Marcelo J. ; Bianchi-Carvalho, Isabela ; Rubira, Rafael J. ; Sanchez-Cortes, Santiago ; Constantino, Carlos J.

• Document type: Journal article
• Source: ACS OMEGA; v. 9, n. 41, p. 11-pg., 2024-10-02.

Abstract

The level of aggregation and aggregate morphology of metallic nanoparticles are factors that influence the SERS signal (surface-enhanced Raman scattering), affecting reproducibility and sensitivity. This study presents a systematic evaluation of the colloidal aggregation on the SERS signal by combining transmission electron microscopy and UV-vis extinction spectroscopy. It focuses on the effect of two methods of sample preparation ("external standard method-ESM" and "standard addition method-SAM") on the SERS signal using the fungicide thiabendazole (TBZ) in Ag colloid as a probe molecule. The TBZ critical concentration (concentration for which SERS reaches the maximum intensity) was 6.0 x 10(-6) mol/L for ESM and 1.5 x 10(-6) mol/L for SAM. Besides, TBZ exhibited a sigmoid-type isotherm for ESM, indicating formation of a TBZ first layer on Ag nanoparticles at lower concentrations (Ag aggregates more compact; size <500 nm) and TBZ multilayers at higher concentrations (Ag aggregates more branched; >2 mu m). For SAM, the TBZ first layer formation was also observed at lower concentrations (Ag aggregates more branched; <2 mu m). However, at higher concentrations, the Ag colloid degradation/precipitation was observed (Ag aggregates more compact; >2 mu m). The Ag aggregation mechanisms align with reaction-limited colloidal aggregation at lower concentrations and diffusion-limited colloidal aggregation at higher concentrations. We believe these results contribute to the SERS research field despite all of the work already done over its 50-year history. (AU)

• FAPESP's process: 18/22214-6 - Towards a convergence of technologies: from sensing and biosensing to information visualization and machine learning for data analysis in clinical diagnosis
• Grantee: Osvaldo Novais de Oliveira Junior
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 23/16725-6 - Development of sustainable SERS substrates for removal and detection of synthetic food dyes in aqueous media
• Grantee: Isabela Bianchi Carvalho
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 22/09619-2 - Colloidal aggregation mechanisms induced by distinct sample preparation methods and their relation with SERS sensitivity and reproducibility
• Grantee: Marcelo José dos Santos Oliveira
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree