Morphological,mechanical, and biocompatibility characterization of macroporous alumina scaffolds coated with calcium phosphate/PVA |
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Authors: | Hermes S Costa Alexandra A P Mansur Edel F Barbosa-Stancioli Marivalda M Pereira Herman S Mansur |
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Affiliation: | (1) Laboratory of Biomaterials and Tissue Engineering, Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais, R. Espírito Santo 35, Belo Horizonte, MG, Brazil;(2) Department of Microbiology, Institute of Biological Sciences, Federal University of Minas Gerais, PO Box 486, 31270 901 Belo Horizonte, MG, Brazil |
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Abstract: | In bone tissue engineering, a highly porous artificial extracellular matrix or scaffold is required to accommodate cells and
guide the tissue regeneration in three-dimension. Calcium phosphate (CaP) ceramics are widely used for bone substitution and
repair due to their biocompatibility, bioactivity, and osteoconduction. However, compared to alumina ceramics, either in the
dense or porous form, the mechanical strength achieved for calcium phosphates is generally lower. In the present work, the
major goal was to develop a tri-dimensional macroporous alumina scaffold with a biocompatible PVA/calcium phosphate coating
to be potentially used as bone tissue substitute. This approach aims to combine the high mechanical strength of the alumina
scaffold with the biocompatibility of calcium phosphate based materials. Hence, the porous alumina scaffolds were produced
by the polymer foam replication procedure. Then, these scaffolds were submitted to two different coating methods: the biomimetic
and the immersion in a calcium phosphate/polyvinyl alcohol (CaP/PVA) slurry. The microstructure, morphology and crystallinity
of the macroporous alumina scaffolds samples and coated with CaP/PVA were characterized by X-ray diffraction (XRD), Fourier
Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM/EDX) analysis. Also, specific surface area was
assessed by BET nitrogen adsorption method and mechanical behavior was evaluated by axial compression tests. Finally, biocompatibility
and cytotoxicity were evaluated by VERO cell spreading and attachment assays under SEM. The morphological analysis obtained
from SEM photomicrograph results has indicated that 3D macroporous alumina scaffolds were successfully produced, with estimated
porosity of over 65% in a highly interconnected network. In addition, the mechanical test results have indicated that porous
alumina scaffolds with ultimate compressive strength of over 3.0 MPa were produced. Concerning to the calcium phosphate coatings,
the results have showed that the biomimetic method was not efficient on producing a detectable layer onto the alumina scaffolds.
On the other hand, a uniform and adherent inorganic–organic coating was effectively formed onto alumina macroporous scaffold
by the immersion of the porous structure into the CaP/PVA suspension. Viable VERO cells were verified onto the surface of
alumina porous scaffold samples coated with PVA–calcium phosphate. In conclusion, a new method was developed to produce alumina
with tri-dimensional porous structure and uniformly covered with a biocompatible coating of calcium phosphate/PVA. Such system
has high potential to be used in bone tissue engineering. |
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