Banca de QUALIFICAÇÃO: RICARDO ALEXANDRE DOS SANTOS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : RICARDO ALEXANDRE DOS SANTOS
DATE: 22/02/2021
TIME: 14:00
LOCAL: Webconferência
TITLE:

Fluorescence of nitrousBODIPYs in the quantification of biotiols.

KEY WORDS:

Biotiols. BODIPYs. Fluorescence. Glutathione. Probe.

PAGES: 60
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUMMARY:

Metabolic processes in living organisms can generate so-called oxidative stress, which is the imbalance of the presence between oxidizing compounds, found in greater quantities and antioxidants, leading to a disruption of signaling and redox control, causing or not molecular damage. Associated with this, we can highlight the great formation of Reactive Oxygen and Nitrogen Species (ERON's), which are precursor compounds of several diseases. Among the most important endogenous, systematic and intracellular antioxidants in combating this process are biotiols, which have been the focus of strong interest in the academic community, more specifically glutathione. The reduced glutathione, together with its catalytic enzymes, help in the regulation of the redox system. The development of spectroscopic analytical techniques based on fluorescence detection using the off-on concept requires fluorescent markers with different characteristics and applicability. Among the variety of fluorescent markers available, BODIPY derivatives have come to be widely used because it is a simple and fast method. The reaction mechanism consists of two processes that can occur concurrently, the addition of the thiol group to the BODIPY pyrrole ring, with additional reduction of the NO group. The experimental conditions were optimized using glutathione reduced to pH = 7.5, Britton Robbinson buffer (10 mM) and the concentration of the BODIPY probe (QHM 300), nitrosated with α-NOClCl modification at 5 µM. In the study of ionic strength using NaCl (0-300 mM), an increase in fluorescence in the concentration of 100 mM was observed. In addition, a kinetic interaction study with the probe was performed, showing a minimum safe reaction time of 20 min. and after this time, the fluorescence intensity remained constant for up to 60 min. demonstrating the photostability of the probe. The proposed method presented a linear concentration range of 0.5-5 µM of reduced glutathione with a detection limit (LOD) of 61.4 nM and relative standard deviations (RSD) of 3.92% and 5.75% for concentrations 1 µM and 5 µM, respectively. Albumin protein, cysteine and fatty acids were the main interferents of the method, simulating conditions of application in blood plasma.

BANKING MEMBERS:
Externa à Instituição - ANA CAROLINE FERREIRA SANTOS - UFAL
Externa ao Programa - 1006306 - JADRIANE DE ALMEIDA XAVIER DOS SANTOS
Interna - 1904678 - JANAINA HEBERLE BORTOLUZZI
Interno - 1613338 - JOSUE CARINHANHA CALDAS SANTOS
Presidente - 2120103 - MARILIA OLIVEIRA FONSECA GOULART