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Made available in DSpace on 2020-12-12T02:31:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-03-01 This study evaluated the mechanical properties and cytocompatibility of recently developed Ti-15Zr-based alloys with Mo addition for potential use as load-bearing implants. The phase composition and microstructure were changed by the alloying elements, being the β phase fully retained on the Ti-15Zr-10Mo and Ti-15Zr-15Mo samples. The TEM analysis showed that a small quantity of ω phase was precipitated on the samples with a high amount of Mo. Regarding the mechanical properties, the Ti-15Zr-10Mo sample presented high mechanical strength and large elongation (854»±»63»MPa and 18.7»±»2.8 %). However, the Ti-15Zr-15Mo sample exhibited better mechanical compatibility, due to its combination of low Young's modulus (75»±»1»GPa) and high Vickers microhardness (346»±»4»HV). Some dimple-type structures found along the fractured surface confirmed the ductile behavior of these samples. The MTT test indicated non-cytotoxic effects of all samples when in contact with osteoblastic cells (p»

Made available in DSpace on 2020-12-12T02:34:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-08-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Titanium alloys are widely used in the biomedical field due to their excellent resistance to corrosion, high mechanical strength/density ratio, low elastic modulus, and good biocompatibility. Niobium is a β-stabilizer element that has the potential to decrease elastic modulus and possesses excellent corrosion resistance. In this article, Ti-15Nb alloy was prepared via arc-melting, with the aim of using it in biomedical applications to replace implants that fail due to mechanical incompatibility with human bone. This Ti-15Nb alloy was structurally, chemically, and microstructurally characterized. Its mechanical properties were analyzed via Vickers microhardness and elastic modulus measurements. The cytotoxicity of the alloy was evaluated via direct and indirect MTT tests. In the direct MTT test, the cells were grown on alloy and in the indirect test, Ti-15Nb alloy extracts were prepared (1 g/1 mL at 310 K for 48 hours). The results of chemical composition showed that the alloy produced has good quality and low content of gaseous impurities, such as oxygen and nitrogen. The obtained results for structure and microstructure indicated the presence of the martensite α’ phase. The microhardness of the Ti-15Nb alloy is superior to that of cp-Ti due to solid solution hardening, and the alloy has a better elastic modulus as compared to pure titanium. Cytotoxic effects were not observed. The Ti-15Nb alloy shows good results of mechanical properties and does not show cytotoxic effects. In addition, morphological variations were not found in the cells and good cell adhesion in all the studied conditions was observed. In general, the alloy proposed in this article has satisfactory characteristics as a biomedical material. Laboratório de Anelasticidade e Biomateriais UNESP - Univ Estadual Paulista IBTN-Br – Institute of Biomaterials Tribocorrosion and Nanomedicine – Brazilian Branch Laboratório de Anelasticidade e Biomateriais UNESP - Univ Estadual Paulista FAPESP: 2009/16.731-9 FAPESP: 2015/09.480-0 FAPESP: 2015/25.562-7 CNPq: 308.204/2017-4 CNPq: 400.705/2015-0

Collagen extracted from fishes has been appearing as an alternative for commercial porcine and bovine collagen and it has been considered interesting especially for membrane manufacturing in tissue engineering. Despite the positive in vitro effects of fish collagen membranes, there is still no understanding of all the benefits that this natural biomaterial plays in the wound healing process, due to the lack of compilation of the results obtained in animal studies. In this sense, the purpose of this study was to perform a systematic review of the literature to examine the effects of fish collagen membranes for skin wound healing in experimental models of skin wound. The search was carried out according to the orientations of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA), and the descriptors of the Medical Subject Headings (MeSH) were defined: "fish," collagen," "skin," and "in vivo". A total of 10 articles were retrieved from the databases PubMed and Scopus. After the elegibility analyses, this review covers the different origins of fish collagen reported in the different papers from the beginning of 2015 through the middle of 2021. The results were based mainly on histological analysis and macroscopic evaluation, and fish skin collagen was responsible for improving the wound healing rate and the process of reepithelization and collagen deposition. In conclusion, fish skin collagen has shown positive results in in vivo studies and may be a potential biomaterial in tissue engineering.

Made available in DSpace on 2019-10-06T15:55:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01 Titanium alloys are widely used in the biomedical field due to their good corrosion resistance, high mechanical strength/density ratio, low elastic modulus, and good biocompatibility. With the addition of β-stabilizers elements (such as tantalum), the decrease of the elastic modulus and excellent corrosion resistance are obtained. Zirconium despite being a neutral element appends a good corrosion resistance to titanium alloys. In this paper, Ti-25Ta-10Zr alloy was prepared and characterized aiming biomedical applications. Structural and microstructural analysis corroborated each other and showed the presence of characteristic peaks of three crystalline structures, hexagonal (α phase) and orthorhombic (α'' phase), dissolved in a matrix with body-centered cubic crystalline structure (β phase). In the indirect cytotoxicity test, no cytotoxic effects were observed on the produced alloy. UNESP - Univ Estadual Paulista, Laboratório de Anelasticidade e Biomateriais, 17.033-360, Bauru, SP, Brazil IBTN-Br - Institute of Biomaterials, Tribocorrosion and Nanomedicine - Brazilian Branch, 17.033-360, Bauru, SP, Brazil

Made available in DSpace on 2020-12-12T02:39:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-12-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Due to excellent biocompatibility and corrosion resistance, the application of titanium alloys in orthopedic and dental implants has been increasing since the 1970s. However, the elasticity of these alloys as measured by their Young’s modulus is still about two to four times higher than that of human cortical bone. The most widely used titanium alloy for biomedical applications is Ti-6Al-4V, however, previous studies have shown that the vanadium used in this alloy causes allergic reactions in human tissue and aluminum, also used in the alloy, has been associated with neurological disorders. To solve this problem, new titanium alloys without the presence of these elements and with the addition of different elements, usually beta-stabilizers, are being developed. Manganese is a strong candidate as an alloying element for the development of new beta-type titanium alloys, due to its abundance and low cytotoxicity. In this study, Ti-10Mo-5Mn, Ti-15Mo-2.5Mn and Ti-15Mo-5Mn alloys were prepared in an arc furnace, which resulted in an alloy structure clearly showing the predominance of the beta phase with a body-centered cubic crystalline structure. The observed microstructure confirmed the results on the structural characterization of alloys. Measurement of the indirect cytotoxicity of the alloys showed that the extracts of the studied alloys are not cytotoxic for fibroblastic cells. UNESP - Univ Estadual Paulista Laboratório de Anelasticidade e Biomateriais IBTN-Br – Institute of Biomaterials Tribocorrosion and Nanomedicine – Brazilian Branch UNESP – Univ Estadual Paulista Departamento de Química UNESP - Univ Estadual Paulista Laboratório de Anelasticidade e Biomateriais UNESP – Univ Estadual Paulista Departamento de Química CNPq: 157.509/2015-0 FAPESP: 2015/25.248-0 FAPESP: 2016/10.615-0 CNPq: 307.279/2013-8

Made available in DSpace on 2020-12-12T02:33:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-02-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Titanium alloys have been widely used as biomaterials, especially for orthopedic prostheses and dental implants, but these materials have Young's modulus almost three times greater than human cortical bones. Because of this, new alloys are being produced for the propose of decreasing Young's modulus to achieve a more balanced mechanical compatibility with the bone. In this paper, it is reported the development of Ti-25Ta alloys as a base material, in which was introduced zirconium, with concentration varying between 0 and 40 wt%, with the aim of biomedical applications. The alloys were prepared in an arc-melting furnace. The microstructural analysis was performed by x-ray diffraction as well as optical and scanning electron microscopy. Selected mechanical properties were analyzed by microhardness and Young’s modulus measurements, and cytotoxicity analysis by indirect test. X-ray measurements revealed the presence of α″ phase in the alloy without zirconium; α″ + β phases for alloys with 10, 20, and 30 wt% of zirconium, and β phase only for the alloy with 40 wt% of zirconium. These results were corroborated by the microscopy results. The hardness of the alloy was higher than that of cp-Ti due to the actions of zirconium and tantalum as hardening agents. The Young’s modulus decreases with high levels of zirconium due to the stabilization of the β phase. The cytotoxicity test showed that the extracts of studied alloys are not cytotoxic for osteoblast cells in short periods of culture. [Figure not available: see fulltext.]. UNESP—Universidade Estadual Paulista Laboratório de Anelasticidade e Biomateriais IBTN/Br—Institute of Biomaterials Tribocorrosion and Nanomedicine—Brazilian Branch IFSP—São Paulo Federal Institute of Education Science and Technology UNESP—Universidade Estadual Paulista Laboratório de Anelasticidade e Biomateriais CNPq: 157.509/2015-0