Paper-based SERS sensors for the detection of forever chemicals

• Grant number: 23/06463-4
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: September 01, 2023
• End date: August 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal Investigator: Italo Odone Mazali
• Grantee: Lucas Magno Freitas Oliveira
• Host Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 14/50906-9 - INCT 2014: in Functional Complex Materials, AP.TEM

Abstract

Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic compounds that epidemiological studies and animal models link to a variety of health problems, such as testicular and kidney cancers, as well as to high environmental prevalence. The standard technique for the identification of PFAS is Liquid Chromatography Tandem Mass Spectrometry, which is financially costly and requires trained professionals. Whereas paper substrates for the surface-enhanced Raman (SERS) signal are more affordable alternatives. And, associated with portable instruments, they allow in situ analysis. This project aims to fabricate flexible SERS substrates by inkjet printing using gold and silver nanoparticles on chromatographic paper. In addition, we will evaluate the effect on Raman signal intensification from the combination of inks composed of metallic gold (spheres) and silver (prisms) nanoparticles. It is expected that distinct chemical affinities of the metals for molecules of the PFAS class will allow the differentiation of members of this class. And that the printing design of the inks (side-by-side, layer-on-layer or blend) will alter the sensitivity of the substrate. The formulation of the nanoparticles inks will be characterized by UV-vis spectroscopy and DLS, and their stability will be followed by monitoring the plasmonic band characteristic of each nanoparticle. Microscopy analysis, SEM-EDS and TEM, will be used to verify the morphology and size distribution of the nanoparticles. The performance of the flexible SERS substrates will be evaluated using Raman spectroscopy with the target analyte and the data set of acquired spectra will be analysed using appropriate chemometric tools, when necessary. (AU)