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Advisor(s)
Abstract(s)
A malária mata mais de um milhão de pessoas por ano e é uma das principais causas de morte em regiões subdesenvolvidas. Assim, o desenvolvimento de técnicas de diagnós-tico rápidas, eficientes e competitivas é essencial.
Este trabalho focou-se no estudo da deformabilidade dos glóbulos vermelhos (GVs) como biomarcador de malária, visto que esta propriedade do sangue está diretamente relacio-nada com as alterações que o parasita provoca ao longo da evolução da doença. Sistemas microfluídicos com estreitamentos abruptos juntamente com técnicas de processamento de imagem permitem determinar parâmetros como a velocidade de escoamento e a defor-mabilidade dos GVs. Assim, utilizando microcanais poliméricos com estreitamentos de 6 μm a 10 μm, efetuou-se um estudo comparativo entre GVs saudáveis e GVs quimica-mente modificados para aumentar a sua rigidez e mimetizar o comportamento do parasita da malária. Os resultados obtidos mostram que os GVs saudáveis se deformam natural-mente para atravessar estreitamentos e recuperam rapidamente a sua forma original após o estreitamento. Em contrapartida, nas amostras modificadas com maiores percentagens de químicos o mesmo não se verificou, ocorrendo várias oclusões.
Conclui-se assim que o aumento da rigidez dos GVs provoca a diminuição da velocidade de escoamento, da deformabilidade e da capacidade de recuperação de forma das células. Este trabalho assume-se como um contributo para o desenvolvimento de novos sistemas de diagnóstico. Tendo em conta as microtecnologias existentes, será possível integrar, num chip, sensores, microeletrónica e plataformas microfluídicas, de forma a criar um método de diagnóstico simples, rápido, preciso e barato para deteção precoce da malária.
Malaria kills more than one million people per year and is one of the leading causes of death in underdeveloped regions. Thus, the development of rapid, efficient and competi-tive diagnostic techniques is essential. This work focused on the study of the deformability of red blood cells (RBCs) as a malaria biomarker, since this blood property is directly related to the changes that the parasite causes throughout the course of the disease. Microfluidic systems with abrupt contrac-tions, along with image processing techniques, allow the determination of parameters such as the flow velocity and the deformability of the RBCs. Thereby, using polymeric microchannels with 6 μm to 10 μm width contractions, it was performed a comparative study between healthy and chemically modified RBCs to increase their stiffness and mimic the malaria parasite effect. The obtained results show that healthy RBCs naturally deform to cross the contractions and rapidly recover their original shape. In contrast, in modified samples with high concentration of chemicals, the same did not occur, with several occlusions being observed. Therefore, it is concluded that increasing the rigidity of the RBCs causes the decrease of the flow velocity, the deformability and the shape recovery capacity of the cells. This work is a contribution to the development of new diagnostic systems. Taking into account the existing microtechnologies, it will be possible to integrate sensors, microelectronics and microfluidic platforms into a chip, in order to create a simple, fast, accurate and low cost diagnostic method for early detection of malaria.
Malaria kills more than one million people per year and is one of the leading causes of death in underdeveloped regions. Thus, the development of rapid, efficient and competi-tive diagnostic techniques is essential. This work focused on the study of the deformability of red blood cells (RBCs) as a malaria biomarker, since this blood property is directly related to the changes that the parasite causes throughout the course of the disease. Microfluidic systems with abrupt contrac-tions, along with image processing techniques, allow the determination of parameters such as the flow velocity and the deformability of the RBCs. Thereby, using polymeric microchannels with 6 μm to 10 μm width contractions, it was performed a comparative study between healthy and chemically modified RBCs to increase their stiffness and mimic the malaria parasite effect. The obtained results show that healthy RBCs naturally deform to cross the contractions and rapidly recover their original shape. In contrast, in modified samples with high concentration of chemicals, the same did not occur, with several occlusions being observed. Therefore, it is concluded that increasing the rigidity of the RBCs causes the decrease of the flow velocity, the deformability and the shape recovery capacity of the cells. This work is a contribution to the development of new diagnostic systems. Taking into account the existing microtechnologies, it will be possible to integrate sensors, microelectronics and microfluidic platforms into a chip, in order to create a simple, fast, accurate and low cost diagnostic method for early detection of malaria.
Description
Mestrado em cooperação com a Universidade do Minho
Keywords
Malária Glóbulos vermelhos