Banca de DEFESA: ISABELA LOUISE PEREIRA LOPES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ISABELA LOUISE PEREIRA LOPES
DATE: 29/08/2023
TIME: 13:30
LOCAL: On-line
TITLE:

NEW BIOMATERIAL BASED ON EXTRACELLULAR MATRIX DECELLULARIZED FUNCTIONALIZED WITH NANOCHITOSAN FOR THE PREPARATION OF BIOCURATIVES

KEY WORDS:

tissue engineering; biodressing; decellularized extracellular matrix; nanochitosan

PAGES: 57
BIG AREA: Ciências Biológicas
AREA: Morfologia
SUMMARY:

The skin is an organ that has great reparative capacity, but some acute and chronic injuries
can trigger significant loss of its architecture. In these cases, tissue engineering can be applied
through the use of scaffolds. Biomaterials composed of decellularized extracellular matrix
(dECM) present low immunogenic response and provide a favorable environment for cell
adhesion and proliferation. Natural polymers, such as nano-chitosan, have been gaining
prominence in biomedical applications because they present healing and antimicrobial
properties. This work proposes the development of a dECM biomaterial functionalized with
nanochitosan for use as a biodressing. To obtain the dECM, fragments of bovine skin were
decellularized by agitation in 1% SDS medium, EDTA, Aprotinin and ATB. The samples
were submitted to histological analysis with H&E, Gomori's Trichrome and Alcian Blue
stains, besides DNA extraction and immunofluorescence. The nano-chitosan was obtained
from the ionic gelation method, and characterized by MET, DLS, SEM and antibacterial
activity. The decellularized fragments were functionalized with the nanoparticles by
adsorption. Characterization of the scaffold was done by histological analysis, AFM, FTIR,
SEM and EDS. The size of the nanochitosan structures ranged between 75.48 ± 13.73nm, and
the images showed a shapeless morphology. The polydispersity index was between 0.393 ±
0.015, being within the recommended parameters for natural polymers. The antimicrobial
activity of nano-chitosan was observed at all concentrations tested (0.26 μg/ml-1
to 19.7

μg/ml-1
) for the bacteria Escherichia coli, Enterobacter cloacae, Salmonella sp. and
Staphylococus aureus. The effectiveness of the matrix decellularization process was proven
by DNA extraction, with no characteristic bands in the decellularized sample compared to the
control. The immunofluorescence showed the absence of cell nuclei in the decellularized
tissue, leaving only some debris. The absence of nuclei was also visualized by histological
analysis, in which it was possible to observe the maintenance of much of the matrix structure
through qualitative evaluation of collagen fibers and preservation of glycosaminoglycans,
with preserved topographical architecture. The EDS and FTIR tests demonstrated good
functionalization of the matrix with the nano-chitosan. The SEM analysis demonstrated that
the dECM scaffold presents adequate structure and porosity to favor cell adhesion and
growth. Thus, this work generates perspectives of nanotechnological biodressing from
xenogenic sources for tissue repair.

BANKING MEMBERS:
Presidente - 1349713 - DANIELA LEITE FABRINO
Interna - 2279745 - ERIKA LORENA FONSECA COSTA DE ALVARENGA
Externa à Instituição - MICHELE MUNK PEREIRA
Interna - 2104326 - RAQUEL ALVES COSTA