23 documents found, page 1 of 3
Applications and properties of PDMS: from biomicrofluidics to transparent face ...
Lima, Rui Alberto Madeira Macedo; Maia, Renata Faria; Souza, Andrews Victor Almeida; Barbosa, Filipe; Carvalho, Denise Andreia Mota[Excerpt] Introduction Many researchers have studied elastomers owing to their outstanding biomechanical properties, including !exibility and chemical stability. Among the different elastomers on the market, polydimethylsiloxane (PDMS) has recently gained prominence (Miranda et al., 2022). This material has been used in a variety of industrial applications, including mechanics, electronics, and biomedicine. Som...
A portable and low-cost optical device for pigment-based taxonomic classificati...
Magalhães, Vitor; Pinto, Vânia Cristina Gonçalves; Sousa, Paulo Jorge Teixeira; Afonso, José A.; Gonçalves, L. M.; Fernández, Emilio; Minas, GraçaThe proliferation of certain phytoplankton species may lead to harmful algal blooms (HABs) that can affect living resources and human health. Therefore, an accurate identification of phytoplankton populations is essential for the sustainable management of some activities relevant for the blue economy, such as aquaculture, being also relevant for environmental monitoring and marine research purposes. Microalgae ...
A proof-of-concept study aiming for the integration of an optical biosensor in ...
Correia, Margarida O.; Sousa, Paulo Jorge Teixeira; Rodrigues, Raquel Oliveira; Minas, GraçaAlzheimer’s disease (AD), a progressive neurodegenerative disorder, is marked by the abnormal production of amyloid-beta (Aβ) fibrils, a key biomarker for diagnosis and illness monitoring. Advanced microfluidic devices, such as brain-on-a-chip (BoC), are innovative preclinical tools with the potential to revolutionize AD early diagnosis and treatment. However, existing BoCs face limitations, including challenge...
Optical sensor system to monitor the pH of circulating media on biomimetic micr...
Mendes, Fernando; Miranda, Inês Sofia Ferreira; Rodrigues, Raquel Oliveira; Ferreira, Gabriel Malheiro; Schütte, Helmut; Gassmann, StefanpH is a physiological parameter of great importance in biomedical research. For example, during cell growth process, pH is usually lowered due to the acidic metabolites released by the cells. This decrease on the pH value can affect biological processes and, consequently, affect the accuracy of the research. To monitor the pH changes along cell engineering experiments, cell culture media is usually complemented...
Numerical and experimental analysis of mixing efficiency in passive micromixers...
Ferreira, Filipe Maurício Santos; Sousa, Paulo Jorge Teixeira; Minas, Graça; Lima, Rui Alberto Madeira Macedo; Pinto, Vânia Cristina GonçalvesPassive micromixers play a critical role in microfluidic applications, particularly in lab-on-a-chip devices, since they do not require external energy input, being simpler, cheaper and portable. This paper reports the mixing efficiency by numerical simulation (using COMSOL Multiphysics) and by experimental validation of two 2D polydimethylsiloxane micromixer geometries. The tested flow rate ratios, 1:1, 1:4 an...
Low-cost photoacoustic system for biomedical applications
Ferreira, João; Pinto, Vânia; Matos, Tiago; Catarino, Susana Oliveira; Minas, Graça; Sousa, Paulo Jorge TeixeiraRecently, the field of photoacoustic (PA) imaging has garnered significant attention due to its ability to provide high-resolution images and real-time monitoring of biological tissues. However, PA systems have relied on expensive and complex laser sources and detection mechanisms, limiting their accessibility for widespread use in both clinical and research settings. So, this work aims to address these limitat...
PDMS porous microneedles used as engineered tool in advanced microfluidic devic...
Maia, Renata Patrícia Faria; Sousa, Paulo Jorge Teixeira; Pinto, Vânia Cristina Gonçalves; Soares, Delfim; Lima, Rui Alberto Madeira MacedoThe advancement of organ-on-a-chip (OoC), as end-use preclinical tool, has been slackened with the techno logical and engineering challenges that in-situ real-time monitoring of physicochemical and biological param eters still represent. In this study, the envisioned solution to surpass this challenge is the integration of a microneedle (MN) patch into a microfluidic device to collect cell culture media directl...
Complementary metal oxide semiconductor-based optical detection system for flui...
Santos, André Alves dos; Ferreira, Gabriel Malheiro; Sousa, Paulo Jorge Teixeira; Sousa, Patrícia C.; Catarino, Susana Oliveira; Minas, GraçaAccurate pH sensing is essential for the effective physiological control of the culture media in organ-on-a-chip (OoC) systems. This work proposes a miniaturized optical detection system, based on optical transmittance, for pH level quantification of the EGM™-2 Endothelial Cell Growth Medium-2 BulletKit™ culture medium. Firstly, using a commercial spectrophotometric setup, a set of wavelengths (500, 560, and 60...
Critical issues on the surface functionalization of plasmonic Au-Ag/TiO2 thin f...
Costa, Diogo; Pereira-Silva, Patrícia; Sousa, Paulo Jorge Teixeira; Pinto, Vânia Cristina Gonçalves; Borges, Joel; Vaz, Filipe; Minas, GraçaThis work reports on the surface functionalization of a nanomaterial supporting localized surface plasmon resonances (LSPRs) with (synthetic) thiolated oligonucleotide-based biorecognition elements, envisaging the development of selective LSPR-based DNA biosensors. The LSPR thin-film transducers are composed of noble metal nanoparticles (NPs) embedded in a TiO2 dielectric matrix, produced cost-effectively and s...
Portable and low-cost fluorometer for phytoplankton monitoring
Sá, Leonardo Rafael Correia; Pinto, Vânia Cristina Gonçalves; Sousa, Paulo Jorge Teixeira; Magalhães, Vitor H.; Carvalho, Denise Andreia MotaPhytoplankton monitoring using fluorescence spectroscopy techniques has been frequently used over time. This monitoring is based on the detection of the main photosynthetic pigment, chlorophyll-a, as its concentration is widely used as a proxy of phytoplankton biomass in the water column. However, the fluorometers available for their measurement and use in the field are still quite expensive and bulky, which li...