CIMO - Capítulos de Livros
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Percorrer CIMO - Capítulos de Livros por Domínios Científicos e Tecnológicos (FOS) "Engenharia e Tecnologia::Engenharia Mecânica"
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- Applications and properties of PDMS: From biomicrofluidics to transparent face masksPublication . Lima, Rui A.; Maia, Renata; Souza, Andrews; Barbosa, Filipe; Carvalho, Denise; Carvalho, Violeta; Neves, Lucas B.; Faria, Carlos; Miranda, Inês; Sousa, Paulo; Zille, Andrea; Teixeira, Senhorinha; Minas, Graça; Machado, Lúcio; Ribeiro, J.E.Polydimethylsiloxane (PDMS) is a versatile silicone elastomer widely used in biomedical engineering due to its exceptional properties, including flexibility, chemical stability, optical transparency, biocompatibility, and ease of manufacturing. This chapter explores the unique characteristics of PDMS and its applications in biomicrofluidics and sustainable product development. PDMS is a hyperelastic material with excellent optical transparency, thermal stability, and gas permeability, making it ideal for various applications such as microfluidics, biomodels, blood analogues, implants, and organs-on-chip platforms. Its biocompatibility minimizes adverse tissue reactions, making it suitable for medical implants and skin treatments. However, its hydrophobic nature can limit certain applications, particularly in bioflow transport phenomena. To address this, surface modification techniques, such as oxygen plasma treatment, have been developed to enhance its wettability and expand its usability. In biomicrofluidics, PDMS is extensively used to create microfluidic devices that study blood cell deformability, aiding in the diagnosis of diseases like cancer, diabetes, and malaria. These devices, featuring contractions and bifurcations, provide valuable insights into microscale blood rheology and flow phenomena, improving our understanding of blood flow behavior and validating numerical simulations. The chapter also highlights the innovative use of PDMS in the production of sustainable transparent face masks. By incorporating recycled PDMS and textile fabrics, these masks feature a transparent window that allows visibility of the user’s lips, making them ideal for individuals who rely on lip-reading. The masks meet European Directive EN 14683:2019 standards, achieving level 2 certification for general public use. They offer excellent breathability, bacterial filtration efficiency, and optical transparency, while also promoting sustainability by reusing PDMS at the end of its life cycle. In conclusion, PDMS is a highly adaptable material with significant potential in biomedical applications and sustainable product development. Despite its hydrophobic nature, advancements in surface modification techniques continue to enhance its functionality, making it a valuable resource for innovative solutions in healthcare and beyond.
- Flow visualizations in polydimethylsiloxane cerebral aneurysm biomodelsPublication . Souza, Andrews; Nobrega, Glauco; Ferrera, Conrado; Puga, Helder; Lima, Rui A.; Ribeiro, J.E.This chapter focuses on the study of intracranial aneurysms (IAs), which are localized dilations of arteries within the skull caused by weakened blood vessel walls. IAs pose a significant risk of rupture, leading to strokes with high mortality and dependency rates. The chapter emphasizes the importance of understanding the hemodynamics and geometry of blood vessels to prevent aneurysm rupture. The authors present an innovative technique for manufacturing intracranial aneurysm biomodels using Polysmooth as a sacrificial material and polydimethylsiloxane (PDMS) for the final model. PDMS is chosen for its transparency, flexibility, and ease of manufacturing, which facilitates flow visualization tests. The biomodels are designed with different geometric configurations (60° and 180° angles between inlet and outlet channels) to analyze the effects of channel geometry on blood flow patterns. The experimental setup includes high-speed video equipment, an inverted microscope, and a syringe pump to simulate blood flow using a glycerol-water solution with suspended particles. The flow visualization tests reveal differences in recirculation areas within the aneurysm based on the channel geometry, highlighting the impact of arterial structure on hemodynamics. The study concludes that the presented manufacturing technique is effective for creating realistic biomodels, enabling detailed analysis of blood flow behavior in aneurysms. This research provides valuable insights for developing numerical models and strategies to prevent aneurysm rupture