Banca de DEFESA: GRICIRENE SOUSA CORREIA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : GRICIRENE SOUSA CORREIA
DATE: 03/03/2022
TIME: 09:00
LOCAL: Google Meet
TITLE:

Preparation of Poly (Vinyl Alcohol) / Hydroxyapatite-Alginate Nanofibers by Electrospinning for Bone Tissue Engineering Applications

KEY WORDS:

hydroxyapatite, alginate, PVA, biocomposite, scaffold and electrospinning

PAGES: 130
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:

Nanofiber scaffolds produced by electrospinning have as main characteristics the high surface area /
volume ratio and the distribution of disordered micrometric pores, which can be good candidates for
bone regeneration, facilitating cell adhesion and adsorption of organic molecules (proteins, amino acids
and polysaccharides). Among the biomaterials, hydroxyapatite (HAp) stands out for having a chemical
composition similar to bones and chemically bonding with bone tissue. The aim of this work was to
synthesize nanometric-sized HAp that could be incorporated into polyvinyl alcohol (PVA) nanofibers by
electrospinning technique. First they were synthesized by hydrothermal (HAH) and chemical
precipitation (HP), and the HP was not possible to electrospun due to the large size of the crystals.
Therefore, in order to control the size of HAp nanocrystals, we induced in situ growth associated with
alginate polymer chains and applied them as biocomposites (HAL). For electrospinning, two
concentrations of PVA solution (10 and 12%) and three concentrations of HAL (0.1, 0.25 and 0.5% (p /
w) were used for fiber preparation. Transmission electron microscopy (TEM) showed HAp similar to
rods with size in diameter and length of (10 ± 2) nm and (34 ± 7) nm, respectively. Morphological,
physical (swelling and degradation), mechanical and biological properties were evaluated and compared
with pure PVA and PVA/HAp scaffold Through the morphology analysis it can be stated that the best
parameters to form nanofibers without imperfection are those that contain 12% of PVA, however, in
membranes with a higher proportion of HAL (0.5% m/v) small surface appears quantities of agglutinated
particles of the biocomposite. We reached values of mean diameter (>110 nm) below what is observed in
the literature, even increasing the concentration of the HAL biocomposite, the values remained
approximate in most of the electrospun fibers. The best tensile strength response among electrospun
scaffold was FH2-0.1 (15.2 ± 2.5 MPa), although the other membranes also present high limits of
mechanical strength. Swelling and degradation rates were estimated weekly in vitro in PBS solution for a
period of 04 weeks. In vitro tests were also applied to assess the biocompatibility of the material studied.
Three cell lines were used in the study of the cell viability of the scaffolds and ceramic powders. In this
assay all samples had satisfactory results in the quantification of viable cells. As for the cell adhesion test
in the FH2-0.1 scaffold, it showed that human gingival fibroblast cells (FGH) adhere and proliferate on
the surface. These and other properties are fundamental conditions to show that these materials have

great potential for applications in bone tissue.

BANKING MEMBERS:
Presidente - 2199290 - BEATE SAEGESSER SANTOS
Externo ao Programa - 2199064 - RICARDO OLIVEIRA DA SILVA
Externo ao Programa - 1630817 - RICARDO YARA
Externo à Instituição - SIDNEY JOSE LIMA RIBEIRO
Externa ao Programa - 1283002 - YEDA MEDEIROS BASTOS DE ALMEIDA