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Modelling the heat distribution in organ-on-a-chip systems using integrated mic...
Ferreira, Gabriel Malheiro; Sousa, Patrícia C.; Catarino, Susana Oliveira; Minas, Graça[Excerpt] Microfluidic systems with integrated heating transducers are of growing interest for applications in biochemical sensing, lab-on-a-chip and organ-on-a-chip (OoC) technologies [1]. Particularly, in OoC systems, temperature monitoring is crucial to maintain the cultured cells in a well-defined microenvironment for proper growth [2]. This monitoring can be achieved through temperature control systems com...
Design of a CMOS Current-to-Frequency Converter for Optical pH Sensing in a cul...
Ferreira, Gabriel Malheiro; Santos, André Alves dos; Sousa, Patrícia C.; Catarino, Susana Oliveira; Minas, GraçaIn organ-on-a-chip systems, accurate pH sensing is essential for an effective physiological control of the cells’ culture media. In this work, there was developed a current-to-frequency (IF) converter integrated with a CMOS photodiode for pH quantification of cells’ culture medium. The selection of the optimal features for the converter configuration, such as input current and resolution, was based on initial c...
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...
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...
On-chip optical microsystem for Plasmodium falciparum malaria detection
Baptista, Vitória Cunha; Ferreira, Gabriel Malheiro; Minas, Graça; Veiga, Maria Isabel; Catarino, Susana OliveiraThe limitations in the currently used diagnostic methods pose challenges to effective malaria control and elimination. To overcome this, herein, optical spectrophotometry is explored for the detection and quantification of low-level Plasmodium falciparum infections. Specifically, we characterize the optical spectra of healthy and infected samples and design, simulate, and fabricate an on-chip optical detection ...
Numerical simulation, fabrication, and characterization of a heating system for...
Ferreira, Gabriel Malheiro; Azevedo, Filipe M.; Sousa, Paulo Jorge Teixeira; Pinto, Vânia Cristina Gonçalves; Catarino, Susana OliveiraIn an organ-on-a-chip (OoC) device, temperature control is essential for a well-controlled and human representative microenvironment. This work presents the design, numerical simulation, fabrication and characterization of three aluminium microheater geometries for temperature control into an OoC device. Two of them are circular-based, with different curvature filleting angles and different line widths, and the...
CMOS spectrophotometric microsystem for malaria detection
Ferreira, Gabriel Malheiro; Baptista, Vitória; Silva, Vitor; Veiga, Maria I.; Minas, Graça; Catarino, Susana OliveiraObjectives: Optical spectrophotometry has been explored to quantify Plasmodium falciparum malaria parasites at low parasitemia, with potential to overcome the limitations of detection in the current diagnostic methods. This work presents the design, simulation and fabrication of a CMOS microelectronic detection system to automatically quantify the presence of malaria parasites in a blood sample. Methods: The de...
A numerical study of the heat distribution generated by a microheater in an org...
Ferreira, Gabriel Malheiro; Sousa, Paulo Jorge Teixeira; Pinto, Vânia Cristina Gonçalves; Catarino, Susana Oliveira; Sousa, Patrícia C.; Minas, GraçaIn an organ-on-a-chip (OoC), temperature must be kept stable for a well-controlled and human representative microenvironment. This work presents the numerical simulation of a microheater to be integrated in a polydimethylsiloxane chamber that will comprise an OoC. Numerical simulations were performed to evaluate the heat distribution, considering the fluid flow and its direction, the microheater and substrate m...
Chip CMOS para deteção de hemozoína por refletância ótica
Ferreira, Gabriel MalheiroAtualmente, a doença da malária provoca ainda a morte de milhares de pessoas em países de baixo poder económico, onde o acesso a técnicas de diagnóstico adequadas é escasso. O projeto apresentado nesta dissertação pretende ultrapassar as limitações dos métodos de diagnóstico atuais, através do desenvolvimento de um dispositivo ótico não invasivo, capaz de detetar a presença do parasita da malária abaixo dos 20 ...
Multilayer thin-film optical filters for reflectance-based malaria diagnostics
Costa, Mariana S.; Baptista, Vitória Cunha; Ferreira, Gabriel Malheiro; Lima, Duarte; Minas, Graça; Veiga, Maria Isabel; Catarino, Susana OliveiraMalaria diagnosis relies on optical microscopy and/or rapid diagnostic tests based on detecting specific malaria antigens. The clinical sensitivity of these methods is highly dependent on parasite density, with low levels of detection at low parasite density, challenging the worldwide malaria elimination efforts. Therefore, there is a need for diagnostic methods with higher sensitivity, demanding innovative dia...