Banca de DEFESA: WINNIE QUEIROZ BRANDAO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : WINNIE QUEIROZ BRANDAO
DATE: 13/10/2022
TIME: 10:00
LOCAL: Programa de Pós-Graduação em Ciência de Materiais
TITLE:

Preparation and Characterization of Composite Materials for Purification and Biosensing of DNA and Removal of Contaminants

KEY WORDS:

Membranes, conductive polymers, DNA purification, gold nanoparticles, DNA detection, magnetic composite.

PAGES: 223
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:

In this work, we describe the preparation and characterization of composite materials and present some of their applications in DNA purification and sensing and the removal of contaminants. The materials developed and characterized were: i) polystyrene-polypyrrole (PS-PPi) membranes, prepared by the electrospinning technique and coated by the in situ polymerization of pyrrole; ii) hen eggshell membranes modified with gold nanoparticles by ultrasonication, and iii) a carboxymethylcellulose magnetic composite (CM-CMC), prepared by the co-precipitation method. The PS-PPi membrane was initially used for the adsorption of salmon sperm DNA dissolved in aqueous solutions when it presented an adsorption capacity of 260 mg/g. Then, these PS-PPi membranes were incorporated into spin columns so that we could optimize a protocol for the extraction and purification of DNA from crisp lettuce leaves. The DNA samples obtained were of excellent integrity and quality. This procedure is presented as a simple and fast protocol for the extraction of DNA from plant tissues. In turn, the MCO-NPsAu system was used as a sustainable platform for the detection of DNA sequences of the pathogen Leptospira interrogans, based on the previous immobilization of single-stranded DNA strands labeled with a fluorophore (FAM-ssDNA) through interactions between ssDNA nucleobases and gold nanoparticles. Hybridization occurs after the MCO-NPsAu/FAM-ssDNA system interacts with the complementary target DNA sequence (cDNA). which leads to the appearance of a strong fluorescence signal. The results obtained revealed that our protocol is a simple, relatively fast, and highly sensitive method, which has a detection limit of 0.24 nM. Finally, we discuss the use of carboxymethylcellulose magnetic composite for the removal of toluidine blue (AT) dye dissolved in an aqueous medium. When compared with those of other adsorbents discussed in the literature, our results indicated that CM-CMC is a promising material for the economical and sustainable removal of dye molecules from aqueous media.

COMMITTEE MEMBERS:
Externo à Instituição - GUILHERME MARIZ DE OLIVEIRA BARRA - UFSC
Externa ao Programa - 1542785 - ADRIANA FONTES - nullInterno - 1301657 - ANDRE GALEMBECK
Presidente - 1130294 - CELSO PINTO DE MELO
Interna - 2572606 - GLORIA MARIA VINHAS