Banca de DEFESA: RODRIGO SILVA NASCIMENTO MANCINI

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : RODRIGO SILVA NASCIMENTO MANCINI
DATA : 24/02/2022
HORA: 13:30
LOCAL: Remoto - meet.google.com/dpv-tynv-zob
TÍTULO:

Human visceral leishmaniasis antibody sensing employing peptide-based bioanalytical platforms supported by chemometric approaches

PÁGINAS: 128
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Analítica
ESPECIALIDADE: Eletroanalítica
RESUMO:

Human visceral leishmaniasis (HVL) is an important neglected tropical disease that caused 90,000 deaths with nearly 12 million people are affected worldwide in 2020. Because therapies for this disease are very aggressive, an early diagnosis is essential. Among the existing methods, they are either expensive and laborious, or need expensive instruments or complicated fabrication methods. For this reason, recent biosensors trends involve the development of new platforms using the antibodies produced by the humoral response employing ultrasensitive detection methods like electrochemical impedance spectroscopy (EIS) and Surface-enhanced Raman Spectroscopy (SERS). With these platforms, reduced sample preparation are provided as well easier and quicker responses. There is also another window of opportunity when employing these methods which is the use of multivariate data analysis to enhance the diagnosis performance. Taking this outlook into consideration, this thesis objective is to develop ultrasensitive platforms supported by chemometric tools to provide a reliable assay to classify human sera in infected or not-infected by HVL. To accomplish it, an antigenic peptide PSAdP23-47 was employed as a recognition element into two bioanalytical platforms. The first platform was assembled by the immobilization of PSAdP23-47 on a gold electrode with an electrospun polyamide-6 (PA6)/chitosan nanofibers to demonstrate the peptide potential to detect leishmanial specific antibodies in clinical samples. This platform used EIS as transduction technical and performed outstandingly; After the optimization, relative changes in impedance were proportional to the logarithmic value of anti-PSAdP23-47 antibodies in the range of 2.5 to 10 pgmL-1 (r2= 0.9946) with a detection limit of 0.2 pgmL-1. The platform also proved to be selective to this specific antibody and provided a reliable response for infected clinical samples and no response for not-infected samples. The second platform was designed using a SERS homogeneous immunoassay using gold nanoparticles– PSAdP23-47 assemblies to transduce the response against anti-PSAdP23-47 antibodies. Light scattering characterization revealed that the peptide addition to the AuNP increases few nanometers of the solvation layer, and with anti-PSAdP23-47 antibody addition, a relevant increase of the solvation layer. Further UV-VIS and SEM studies also revealed that the latter step promoted aggregation of AuNP/PSAdP23-47, providing a complex SERS spectra, enabling remarkable enhancements. Employing multivariate curve resolution alternating least squares (MCR-ALS), we were able to find a fingerprint region that differentiate infected from non-infected samples. With the partial least squares discriminant analysis (PLS-DA) model, it was possible to achieve 100% sensitivity and 88.2% specificity for external samples. In summary, two platforms ultrasensitive platforms were developed to advance the fight against the HVL. While the first platform proved to be a robust platform to detect specific antibodies in clinical samples in very low concentrations, the second one proved to be versatile and reliable methodology. Although a complex spectra was acquired, chemometric tools were able to identify signature regions and use them to classify correctly clinical samples. These achievements bring important contributions not only for HVL diagnosis but also for bioanalytical research, allowing the advance of the modular concept and the multivariate approach to solve complex problems.

MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1544341 - WENDEL ANDRADE ALVES
Membro Titular - Examinador(a) Interno ao Programa - 1654772 - CAMILO ANDREA ANGELUCCI
Membro Titular - Examinador(a) Externo ao Programa - 2604128 - ALEXANDRE JOSE DE CASTRO LANFREDI
Membro Titular - Examinador(a) Externo à Instituição - THIAGO REGIS LONGO CESAR DA PAIXAO - USP
Membro Titular - Examinador(a) Externo à Instituição - Lauro Tatsuo Kubota - UNICAMP
Membro Suplente - Examinador(a) Interno ao Programa - 3047441 - MONICA BENICIA MAMIAN LOPEZ
Membro Suplente - Examinador(a) Externo ao Programa - 1600858 - HERCULANO DA SILVA MARTINHO
Membro Suplente - Examinador(a) Externo à Instituição - JOSÉ ALBERTO FRACASSI DA SILVA - UNICAMP