Percorrer por autor "Barbosa, Filipe"
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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.
- Experimental Investigation of Green Nanofluids: Assessment of Wettability, Viscosity and Thermal ConductivityPublication . Nobrega, Glauco; Cardoso, Beatriz D.; Barbosa, Filipe; Pinho, Diana; Abreu, Cristiano; Souza, Reinaldo Rodrigues de; Moita, Ana S.; Ribeiro, J.E.; Lima, Rui A.Metallic nanoparticles are a type of nanomaterial synthesized from metallic precursors. Due to their unique physiochemical, electrical, and optical properties, metallic nanoparticles are widely studied and applied in various areas such as medicine, electronics, and heat transfer systems. However, conventional synthesis methods to produce metallic nanoparticles face challenges such as instability and environmental concerns, prompting the exploration of greener synthesis methods. Green synthesis uses natural resources like plants and algae as reducing agents, offering a more environmentally friendly approach for the synthesis of metallic nanoparticles. These green-synthesized metallic nanoparticles can enhance heat transfer by becoming part of nanofluids (NFs), which are colloidal mixtures of NPs in a fluid base. NFs, employed for heat transfer. As a result, it is essential to characterize the NFs regarding wettability, viscosity, and thermal conductivity. The results of the spectrophotometer confirmed the green synthesis of NPs, and it was observed that the increase in NP concentration impacted the contact angle, improving the ability to wet. The thermal conductivity is also modified, with an improvement of 11.3% compared to distilled water, without a significant increase in fluid viscosity.
- Recent Advances of PDMS In Vitro Biomodels for Flow Visualizations and Measurements: From Macro to Nanoscale ApplicationsPublication . Souza, Andrews; Nobrega, Glauco; Neves, Lucas B.; Barbosa, Filipe; Ribeiro, J.E.; Ferrera, Conrado; Lima, Rui A.Polydimethylsiloxane (PDMS) has become a popular material in microfluidic and macroscale in vitro models due to its elastomeric properties and versatility. PDMS-based biomodels are widely used in blood flow studies, offering a platform for improving flow models and validating numerical simulations. This review highlights recent advances in bioflow studies conducted using both PDMS microfluidic devices and macroscale biomodels, particularly in replicating physiological environments. PDMS microchannels are used in studies of blood cell deformation under confined conditions, demonstrating the potential to distinguish between healthy and diseased cells. PDMS also plays a critical role in fabricating arterial models from real medical images, including pathological conditions such as aneurysms. Cutting-edge applications, such as nanofluid hemodynamic studies and nanoparticle drug delivery in organ-on-a-chip platforms, represent the latest developments in PDMS research. In addition to these applications, this review critically discusses PDMS properties, fabrication methods, and its expanding role in micro- and nanoscale flow studies.