Navegando por Palavras-chave "Bioactive Material"

Agora exibindo 1 - 2 de 2
  • Nenhuma Miniatura disponível
    Item
    Somente Metadadados
    Caracterização físico-química e avaliação do efeito biológico da biosilica proveniente da espécie de esponja marinha tedania ignis
    (Universidade Federal de São Paulo, 2018-09-21) Cruz, Matheus de Almeida [UNIFESP]; Renno, Ana Claudia Muniz [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Bone fractures are an important event in the medical clinic and are mainly related to the occurrence of trauma, accidents, sports injuries and diseases. In this context, biomaterials have been gaining prominence as an alternative in the treatment of fractures, especially the active bioglass 45S5, which is considered the gold standard of performance in the treatment of fractures. However, the great problem of this resource is due to its high cost of manufacturing or importation, which makes its access to the population restricted. Thus, research that seeks to prospect for natural products that have a good performance in bone repair becomes more and more necessary. In this context, marine sponges, which are already the marine organisms most used in medical research, present in their skeleton an organic portion, which is an analogue of collagen type XIII called spongin, in addition to an inorganic portion called Biosilica (BS), which makes up the spicules of these marine organisms. In this context, the objective of this work was: (i) to characterize physicochemically the BS and (ii) evaluate the biological effect of BS by in vivo analyzes. BG 45S5 was used for comparison in both cases. The characterization was done through MEV / EDX, XRD, FTIR, Calcium test and pH. For the in vivo tests, histopathological, histomorphometric and three-point biomechanical tests were performed. The results of SEM / EDX indicated that BS, after its extraction, showed spike structures with presence of Si (Silica) and O (oxygen) elements in its composition, while BG presented particles of varying size and shape with presence of the elements Si (Silica), O (Oxygen), Ca (Calcium), Na (Sodium), Al (Aluminum), Mg (Magnesium) and P (Phosphorus). In the FTIR results, it was possible to observe peaks referring to the groups Si-OH and Si-O-Si in BS and BG, besides the BG present a peak referring to the P-O. The XRD spectrum demonstrated the predominantly amorphous character of BS, but still with crystalline peaks characteristic of silica containing samples, while BG was completely amorphous. In the Ca assay, BS on day 1 demonstrated mineralization while BG demonstrated ion release from the incubation solution. However, from day 3, BS and BG demonstrated to release Ca in the incubator solution, this process being more prominent in BG until the last period. The pH analyzes allowed to observe that BS acidified the incubation medium on day 1 and, from the third day, the same reached a plateau near the physiological pH, while BG demonstrated to alkalinize the medium of day 1 until day 21. The results of the histopathological analysis, in tibiae of rats after 15 days, demonstrated extensive formation of bone tissue in Control Group (GC), presenting areas of osteoid tissue. BS demonstrated to be biocompatible, with initial formation of neoformed bone tissue, mainly in the periphery of the defect, presenting osteoid tissue, besides extensive formation of granulation tissue organized around BS particles. BG presented areas of formation of neoformed bone tissue largely than BS, with a large volume of osteoid tissue interspersed by BG particles and less evident granulation tissue. The histomorphometric parameter for the osteoblastic surface (Ob.S / BSf) demonstrated the bioactivity and anabolic effect of Biosilica. Biomechanical analysis demonstrated good mechanical properties of BS. Finally, it was possible to conclude that BS may present great potential in the fracture repair process, however, more biological studies with longer experimental periods and with different forms of presentation of the material are still necessary, in order to elucidate the mechanisms involved in the repair and to optimize the performance of this new material.
  • Nenhuma Miniatura disponível
    Item
    Somente Metadadados
    Efeitos Do Compósito De Biosilicato® E Plga Associado Ou Não A Terapia Laser De Baixa Intensidade No Processo De Reparo Ósseo
    (Universidade Federal de São Paulo (UNIFESP), 2017-01-30) Fernandes, Kelly Rossetti [UNIFESP]; Renno, Ana Claudia Muniz [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The search for new technologies that act on the bone healing process is necessary due to the high mortality and morbidity associated with bone fractures. For this, a promising alternative for the treatment of fractures is the use of Biosilicate (BS) composites which is a highly bioactive glass ceramic, combined with microspheres of the polymer poly (D, L-lactic acid-co-glycolic acid) (PLGA). In addition, another method of treatment that has shown promising effects during the bone repair is a low level laser therapy (LLLT). In this context, two studies (I and II) were conducted investigating the effects of a BS and PLGA composite in different proportions with or without LLLT. Thus, the present study had the following objectives: (i) to produce and characterize BS/PLGA composites in different proportions; (ii) to evaluate the biocompatibility of BS/PLGA composites, in different proportions, through in vitro studies; (iii) to evaluate the effects of BS/PLGA composites on the repair of bone defects induced in rat tibia; (iv) to evaluate the effects of BS/PLGA 80/20 composites associated or not with low level laser therapy through in vitro and in vivo studies. In study I, BS and BS/PLGA composites with different proportions (BS/PLGA 80/20; BS/PLGA 70/30; BS/PLGA 60/40) were produced. The physical chemical characterization of these materials was carried out through the analysis of pH, mass loss, XRD, SEM and setting time of the material. For the in vitro test, the cell viability of osteoblasts and fibroblasts in contact with the extract of the different composites was evaluated. Furthermore, for the in vivo tests, the histopathological and immunohistochemical (RUNX2 and RANKL) analyzes of the composites implanted in bone defects in the tibiae of rats were performed. Regarding study II, physical chemical characterization was performed through SEM and FTIR. For in vitro tests, the cell viability of osteoblastic and fibroblast cells in contact with BS and BS/PLGA 80/20 extract and irradiated with LLLT (Ga-Al-As, 808 nm, 10 J.cm- ²) were evaluated. Finally, in the same study, BS and BS/ PLGA 80/20 implants were implanted into a bone defect induced in rat tibiae and the animals were irradiated with LLLT (Ga-Al-As, 808 nm, 30 J.cm- ²) 3 times a week for 2 and 6 weeks. The results of study I showed that the composites presented a decrease of pH, mass loss over time. In addition, the formation of hydroxyapatite, presence of pores and loss of composite integrity were observed after incubation in PBS. In the in vitro tests, BS/PLGA composites showed a significant increase in the viability of osteoblasts and fibroblasts. Histopathological and immunohistochemical analyzes revealed that the BS/PLGA groups, especially the BS/PLGA 60/40, presented a greater biological response, indicated by the increase in the rate of degradation of the material, presence of newly formed bone in the defect area and the increase of RUNX2 and RANKL immunolabeling. In the study II, it was possible to observe through the SEM and FTIR results that the PLGA microspheres were successfully inserted in the BS and that there was degradation over time of these composites. In vitro tests demonstrated increased viability of osteoblasts and fibroblasts in the BS/PLGA groups associated with LLLT. Finally, the animals treated with BS/PLGA + LLLT showed an improved material degradation and an increased amount of granulation tissue and newly formed bone tissue. Considering the results of the two studies it is concluded that the BS/PLGA composites are non-cytotoxic and biocompatible. In addition, it was concluded that the association of BS/PLGA with LLLT was able to optimize bone repair. In sum, the innovative and promising BS/PLGA composites associated to LLLT have potential to be used in bone repair engineering.