Banca de DEFESA: MÔNICA RODRIGUES DE SÁ

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : MÔNICA RODRIGUES DE SÁ
DATE: 25/09/2024
TIME: 14:00
LOCAL: online
TITLE:

Double self-ordering systems of latex and silver nanoparticles for use in SERS-type
sensors.

KEY WORDS:

Látex nanoparticles; Silver nanoparticles; self-ordering; SERS.

PAGES: 100
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:

Limited sensitivity and the difficulty in obtaining a reproducible signal are two major challenges that
hinder the practical application of SERS substrates. Latex nanoparticles exhibit high monodispersity, a
crucial characteristic for the spontaneous formation of ordered macrocrystals, which can be used in
optical applications. These particles emerge as an alternative for preparing more stable self-organized
substrates for surface-enhanced Raman scattering (SERS). Nanostructured arrangements are highly
valued for SERS substrate preparation due to their excellent stability and signal reproducibility. In this

study, we present a new approach for manufacturing an active SERS substrate from doubly self-
organized latex and silver nanofilms, which possess high sensitivity to the analyte. The method used for

preparing the SERS substrates is cost-effective, easy to operate, and offers good reproducibility, while
also reducing the amount of reagents and samples as well as processing and detection time. This method
is not only fast and efficient but also presents excellent application prospects.
Moreover, the substrate stands out for its ability to utilize different excitation laser sources, which can
potentially enhance the detection of trace analytes. The distribution of AgNPs and their location at the
edges of the latex nanoparticles help create highly dense electromagnetic field hotspots, increasing the
interaction between the analyte and the substrate, and consequently improving the detection signals of the
analyte adsorbed on the substrate surface. The detection limit for R6G on the SERS substrates was 0.5
ppb, with an Enhancement Factor (EF) of up to 83,000 times. Detection of melamine at concentrations of
up to 100 ppb was achieved, and the substrates demonstrated stability for 90 days. The macroscopic
uniformity of the substrates ensured the reproducibility of the SERS signals, making them ideal
candidates for SERS applications.

COMMITTEE MEMBERS:
Externo à Instituição - ANDREAS STINGL
Presidente - 1301657 - ANDRE GALEMBECK
Interno - 1129726 - CID BARTOLOMEU DE ARAUJO
Externo à Instituição - RAMÓN RAUDEL PEÑA GARCIA
Interno - 1354207 - SEVERINO ALVES JUNIOR