Programa de Pós-Graduação em Engenharia de Recursos Naturais da Amazônia - PRODERNA/ITEC
URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/4044
O Programa de Pós-Graduação em Engenharia de Recursos Naturais da Amazônia (PRODERNA) do Instituto de Tecnologia da UFPA (ITEC) da Universidade Federal do Pará (UFPA), em nível de Doutorado, tem como objetivos principais: formar quadros profissionais qualificados na área de Engenharia de Recursos Naturais; incentivar a pesquisa e o aprofundamento dos estudos técnicos e científicos relacionados ao uso e a transformação de recursos naturais; e contribuir para o desenvolvimento científico e tecnológico da região Norte.
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Item Acesso aberto (Open Access) Biocompósito a partir de PLA, Biovidro e Nanotubos de Carbono por Impressão 3D visando Regeneração Óssea(Universidade Federal do Pará, 2023-03-31) VASCONCELOS, Esleane Vilela; REIS, Marcos Allan Leite; http://lattes.cnpq.br/8252507933374637; https://orcid.org/0000-0003-2226-2653; CANDIDO, Verônica Scarpini; http://lattes.cnpq.br/8274665115727809; https://orcid.org/0000-0002-3926-0403Bone involvement promoted by aging and accidents has aroused interest in biomaterials and technologies for bone regeneration purposes. Thus, 3D printing technology gained prominence in the production of scaffolds due to its versatility in the production of complex geometries with interconnected pores. In this work, scaffolds composed of poly (lactic acid) (PLA), bioglass (BV) and carbon nanotubes (NTC) were produced by 3D printing, using hexagonal geometry, similar to honeycomb, interleaved. Poly (lactic acid) is a biopolymer already used in biomaterials, while bioglass has proven to be an excellent strategy for use in bone regeneration due to its excellent properties of biocompatibility, bioactivity and osteointegration, however they have low mechanical resistance and carbon nanotubes have shown excellent mechanical reinforcement in composite biomaterials. Thus, the main objective of this study was to produce and characterize a biocomposite of PLA, bioglass and carbon nanotubes by 3D printing and to study its chemical structure, crystallineity and morphology, using fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction and scanning electron microscope. The thermal stability of the composite was evaluated by thermogravimetry, mechanical properties by compression tests and cell viability was determined by the Alamar Blue test. The bioglass was synthesized by sol-gel method presenting bioactive phases of silicate. The scaffolds were produced by 3D printing with hexagonal structures in honeycomb in PLA, PLA/BV and PLA/NTC that were impregnated with bioglass on its surface. The results of the scaffolds demonstratedinterconnected and well-defined pores, ranging from 130 μm to 800 μm. Raman spectroscopy confirmed the interaction of BV in the polymer matrix through new peaks in the spectrum between 1400 and 2600 cm-1 and the presence of the D, G and 2D bands of NTC. In the compression assay, PLA scaffolds with 2 mm diameter showed higher compression stress of 14.88 ± 2.35 MPa, while PLA/NTC higher modulus of apparent compression, 0.58 ± 0.36 GPa. In cell viability, statistical tests showed that there was no significant difference between scaffolds with 2 and 4 mm diameter. The results reveal promising results for the use of 3D printed composites in bone repair sponges. Thus, we suggest the composite of PLA/NTC of 4mm impregnated with BV on the surface as the best bone substitute, however, the application in implants remains limited in relation to osteogenic integration.Item Acesso aberto (Open Access) Manufatura aditiva de biocompósitos a partir de ácido poliláctico reforçado por hidroxiapatita e nanotubos de carbono para regeneração de tecido ósseo(Universidade Federal do Pará, 2024-01-22) BELO, Francilene da Luz; REIS, Marcos Allan Leite dos; http://lattes.cnpq.br/8252507933374637; CANDIDO, Verônica Scarpini; http://lattes.cnpq.br/8274665115727809Bone tissue is one of the most important tissues in the human body. Unfortunately, some traumatic events can cause fractures that can lead to temporary or permanent disability. Scaffolds are some of the materials that help in the treatment of these fractures, as they play an important role in the bone repair process and can be manufactured by 3D printing. Polylactic acid (PLA), as it is biodegradable, is one of the materials used in the production of scaffolds. Furthermore, the association of PLA and hydroxyapatite (HA) in its manufacture has shown excellent results, accelerating bone regeneration and reducing healing time. Another promising material for making scaffolds are carbon nanotubes (CNT), which have excellent mechanical properties and also accelerate bone growth. Thus, the main objective of this study was to produce scaffolds by additive manufacturing from polylactic acid (PLA) reinforced with hydroxyapatite (HA) and carbon nanotubes (CNT), to be applied in the regeneration of bone tissue and characterized through mechanical and biological. Hydroxyapatite was synthesized by wet means and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), presenting phases characteristic of HA, characteristic groups and a morphology with a porous surface with varying particle sizes, important characteristics for a biomaterial. The pure PLA, PLA/HA and PLA/NTC scaffolds were produced by additive manufacturing with an opening between the walls of 1 mm and 2 mm and characterized through mechanical tests and biological tests. Furthermore, PLA/NTC scaffold samples were impregnated with HA on the surface by thermal and chemical treatment to evaluate the influence of ceramics on the composite surface. The micrograph of the scaffolds showed that the addition of CNT made the PLA surface rougher compared to the sample containing HA; The TGA curves suggested that temperature may favor the thermal stability of PLA/NTC scaffolds impregnated with HA on the surface; Ramam showed an interaction between hydroxyapatite on the CNT surface and a possible structural transformation of PLA/CNT; In compression tests, PLA/NTC scaffolds with an opening between the walls of 1 mm showed better compression resistance; In cell viability assays, fibroblasts incubated with pure PLA, PLA/HA and PLA/NTC scaffolds showed high viability after evaluation by the MTT assay for the two forms of preparation (heat treatment impregnation and chemical treatment impregnation and for the two openings between the walls. More than 85% of the cells remained viable after 48h of incubation with all scaffolds tested, with the groups that had NTC in their composition showing the best results, both for heat treatment (more than 95% of cell viability) as well as chemical treatment (acetone). Given the results presented, it is concluded that PLA scaffold reinforced with HA and CNT may be promising as a biomaterial used to aid in the regeneration of bone tissue, contributing to the reduction of time hospitalization of patients suffering from bone fractures.