Banca de QUALIFICAÇÃO: AMANDA ELIANE SABAINE

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : AMANDA ELIANE SABAINE
DATA : 02/05/2024
HORA: 14:00
LOCAL: Bloco B - Campus Santo Sandré
TÍTULO:

Covid-19 Rapid Detection Through Immunodominant Peptide-Based Biosensors

PÁGINAS: 30
RESUMO:

COVID-19 is an infectious disease caused by the SARS-CoV-2 virus with a high transmission rate. For this reason, rapid tests designed to identify the disease have been crucial, but virus mutations have potentially impacted the accuracy of these diagnostic tests. Recent studies have focused on identifying immunodominant epitopes in the RBD region, peptides capable of identifying linear IgG and IgA binding regions. Among these peptides, P44 demonstrated superior reactivity and is in a mutation hotspot region in several variants. Consequently, this peptide was selected for constructing biosensors based on SERS and electrochemical techniques, enabling ultra-sensitive detection that provides fast, accurate, and reliable results - particularly vital where rapid identification is critical. Gold nanoparticles (AuNPs) with an average size of 30 nm were synthesized using the Turkevich method. These AuNPs were functionalized with the P44-WT (Wild-Type) peptide and its mutated form, P44-P1 (Gamma variant), using 4-mercaptobenzoic acid (MBA) as a stabilizing agent, which helped control their size, shape, and stability. The functionalization of AuNPs was confirmed through UV-Vis assays, which displayed a displacement of the plasmonic band from 535 nm to 600 nm, and by DLS measurements, indicating an increase of approximately 52 nm in the hydrodynamic radius. This confirms functionalization and antibody recognition. The spectra obtained from SERS analysis were analyzed using the multivariate PLS-DA technique, which showed 100% sensitivity and 90% specificity for samples (n=104). Additionally, electrochemical tests were performed, replicating the SERS platform on glassy carbon electrodes. These tests have confirmed the peptide-antibodies interaction, with detection limits of 0.43 ng mL^-1 for P44-WT and 0.98 ng mL^-1 for P44-P.1. To validate these assays, sera from convalescent COVID-19 patients confirmed by ELISA were used. The data suggest that even minor mutations can influence the response, but the developed assay still allows efficient disease discrimination. These results are a promising methodology to recognize antibodies specific to SARS-CoV-2, even in scenarios of rapid virus mutation. Furthermore, if this methodology can be applied to other diseases, it would merely require identifying the appropriate peptide for antibody recognition.

MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1669182 - JOSE FERNANDO QUEIRUGA REY
Membro Titular - Examinador(a) Externo ao Programa - 3047441 - MONICA BENICIA MAMIAN LOPEZ
Membro Titular - Examinador(a) Externo à Instituição - KEITY SOUZA SANTOS
Membro Suplente - Examinador(a) Interno ao Programa - 1707133 - ISELI LOURENCO NANTES
Membro Suplente - Examinador(a) Interno ao Programa - 1734908 - FABIO FURLAN FERREIRA
Membro Suplente - Examinador(a) Interno ao Programa - 2604128 - ALEXANDRE JOSE DE CASTRO LANFREDI
Membro Suplente - Examinador(a) Externo ao Programa - 1544365 - GISELLE CERCHIARO