Banca de QUALIFICAÇÃO: KARINA AUXILIADORA BRENES ARGUELLO
Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.DISCENTE : KARINA AUXILIADORA BRENES ARGUELLO
DATA : 30/03/2020
HORA: 14:00
LOCAL: sala 306, 3º andar, Bloco B, Campus SA da Fundação Universidade Federal do ABC, localizada na Avenida dos Estados, 5001, Santa Terezinha, Santo André, SP
TÍTULO:
Synthesis of nanostructured lipopeptides as new drug delivery systems: Shape and size effects on cell viability
PÁGINAS: 100
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Físico-Química
ESPECIALIDADE: Química de Interfaces
RESUMO:
We have prepared four lipopeptides PRWG-(C18), PRWG-(C18)2, PK(GCP)WG-C18, and PK(GCP)WG-(C18)2 named LPKBA1, LPKBA2, LPKBA3, LPKBA4 respectively. The lipopeptides PRWG-C18 (LPKBA1) and PRWG-(C18)2 (LPKBA2) have in its structure the amino acids L-proline (P), L-arginine (R), L-tryptophan (W), and L-glycine (G). Lipopeptides PK(GCP)WG-C18 (LPKBA3), and PK(GCP)WG-(C18)2 (LPKBA4) have in their peptide sequence the amino acids L-proline (P), L-Lysine (K), L- tryptophan (W), and L-glycine (G), in these lipopeptides, the amino acid lysine was functionalized with the synthetic amino acid guanidiniumcarbonyl pyrrole (GCP). The inclusion of the GCP in the peptide sequence is mainly due to its high protonation capacity, translocation ability, transport, and its high capacity to bind phosphate groups in molecules such as DNA. The amino acid glycine was coupled in each peptide sequence to confer mobility to the linear (C18) and double aliphatic chains (C18)2 of 18 carbon atoms and mainly by having an esterification percentage of 82%. The preparation of these lipopeptides consisted of three stages, the synthesis of the tripeptides PRWG and PK(GCP)WG in solid phase through a series of coupling reactions using the Fmoc-strategy, the coupling between the two tripeptides (PRWG and PK(GCP)WG) with every linear and double aliphatic chain and finally the removal of the protective groups in slightly acidic conditions. The coupling of these peptides with molecules such as lipids and polymers provides certain advantages as potential drug carriers in the selective release of bioactive, as high encapsulation efficiency, high bioavailability, and low toxicity. Fluorescence spectrophotometry studies, were carried out to determine the critical aggregation concentration (CAC), to evaluate self-organization processes, based on the relative intensity of the tryptophan emission at 350 nm. The cytotoxicity of this compound was evaluated in HEK293 and HeLa cells using the MTT assay [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide], whose IC50 values demonstrate that for LPKBA1 and LPKBA1 were below the CAC and for LPKBA3 and LPKBA4 were above their estimated CAC values. Fluorescence microscopy studies were carried out to determine the behavior of the material and its effects on the mitochondrial membrane potential, observing a change in the appearance of the nucleus between the control, the minimal concentration and the highest concentration which agrees with the cell viability studies. This study shows that the change in the peptide sequence influences the shape, size, and self-organization of the material, which in turn determines the viability of these materials. According to the different results presented, it is demonstrated that the materials LPKBA1 and LPKBA1 can be used in their molecular forms and tested for other types of cell lineages; however, lipopeptides LPKBA3 and LPKBA4 are promising materials since they can be used as transporters of drugs in their molecular form as self-organized.
MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1676364 - JULIANA MARCHI
Membro Titular - Examinador(a) Externo ao Programa - 1544379 - ANDERSON ORZARI RIBEIRO
Membro Titular - Examinador(a) Externo ao Programa - 1675708 - DANIELE RIBEIRO DE ARAUJO
Membro Titular - Examinador(a) Externo ao Programa - 1672728 - ANA CAROLINA SANTOS DE SOUZA GALVAO
Membro Suplente - Examinador(a) Interno ao Programa - 1734908 - FABIO FURLAN FERREIRA
Membro Suplente - Examinador(a) Interno ao Programa - 2946001 - ANTONIO ALVARO RANHA NEVES
Membro Suplente - Examinador(a) Externo ao Programa - 2353139 - ELOAH RABELLO SUAREZ
Membro Suplente - Examinador(a) Externo ao Programa - 1674592 - TIAGO RODRIGUES