Publicação
A new generation of microfluidic platforms based on smart and multifunctional materials
| Resumo: | A precise diagnostic is a key part of the clinical practice as it is essential to provide a correct clinical decision-making for both health professionals and policy makers in terms of public health. In this respect, the primary goal of this project is to develop new solutions that take advantage of the beneficial qualities of Portable Analytical Devices (PADs) and the microfluidic paper-based analytical devices (μPADS), while addressing their technological limitations such as the uncontrolled passive flow rate, the weak mechanical properties or the lack of simple functional reactions, that have a significant impact on their potential to achieve real-life applications and commercialization. To achieve such objective, different polymer-based substrates have been developed, characterized and tested for the printing of PADs and different fillers have been added to printable waxes aiming to induce multifunctionality on the PADs. In this context, poly(l-lactic acid) (PLLA), poly(vinylidene fluoride-co-trifluorethylene) (P(VDF-TrFE)), poly(D,L-lactic- coglycolide) (PDLG), silk and silk fibroin, were processed in different morphologies. Each substrate revealed characteristics of great interest, such as the maximum capillary flow rate of PLLA oriented fiber substrates (70.2 ± 1.9 mm.min-1), the high mechanical strength of P(VDF-TrFE) substrates (ranging from 71.4 ± 2.9 to 163.4 ± 5.1 MPa), the rapid degradation rate of PDLG (≈90 % weight loss in six weeks), or the stability of silk-based substrates which are capable of maintaining high accuracy after three utilizations, using different analytes (albumin, uric acid and glucose), with an minimum R2 of 0.967. The next objective of this project was to increase the versatility of the wax printing technique in terms of functional materials. Three different types of hydrophobic wax-based inks have been developed: magnetic, dielectric and conductive. Magnetic waxes (with Fe3O4 nanoparticles) exhibited an actuation capability with a deformation of ≈12 mm when a magnetic field of 105 mT was applied, and an energy harvesting aptitude with an energy density of about 9.7 mW.cm−3. Active waxes with dielectric properties (with BaTiO3 nanoparticles), exhibited optimized dielectric properties up to ε= 18 at 10 kHz. Conductive waxes (with carbon nanotubes and graphene) exhibited high electrical conductivity values (up to ≈ 2.5×10-4 S.m-1), high gauge factor (up to 11), and a pressure sensitivity of (up to 0.17 MPa-1). In order to demonstrate the technological significance of the produced materials, two μPADS systems have been developed: i) a magnetic origami system completely printed on paper suitable for the detection of infectious diseases and magnetic biomarkers; and ii) a low-power thermal actuation system, based on the printing of conductive wax composites with integrated graphene nanoplatelets (GNP), that was able to work simultaneously as a barrier and as a heater. Thus the materials developed in this thesis hold great promise for the next generation of versatile, effective and accurate PADs and μPADS. |
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| Autores principais: | Pereira, Ricardo Jorge Brito Gonçalves |
| Assunto: | Microfluidic Multifunctional waxes Point-of-care Polymer-based substrates Ceras multifuncionais Microfluídica Substratos de base polimérica Engenharia e Tecnologia::Engenharia dos Materiais |
| Ano: | 2023 |
| País: | Portugal |
| Tipo de documento: | tese de doutoramento |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | A precise diagnostic is a key part of the clinical practice as it is essential to provide a correct clinical decision-making for both health professionals and policy makers in terms of public health. In this respect, the primary goal of this project is to develop new solutions that take advantage of the beneficial qualities of Portable Analytical Devices (PADs) and the microfluidic paper-based analytical devices (μPADS), while addressing their technological limitations such as the uncontrolled passive flow rate, the weak mechanical properties or the lack of simple functional reactions, that have a significant impact on their potential to achieve real-life applications and commercialization. To achieve such objective, different polymer-based substrates have been developed, characterized and tested for the printing of PADs and different fillers have been added to printable waxes aiming to induce multifunctionality on the PADs. In this context, poly(l-lactic acid) (PLLA), poly(vinylidene fluoride-co-trifluorethylene) (P(VDF-TrFE)), poly(D,L-lactic- coglycolide) (PDLG), silk and silk fibroin, were processed in different morphologies. Each substrate revealed characteristics of great interest, such as the maximum capillary flow rate of PLLA oriented fiber substrates (70.2 ± 1.9 mm.min-1), the high mechanical strength of P(VDF-TrFE) substrates (ranging from 71.4 ± 2.9 to 163.4 ± 5.1 MPa), the rapid degradation rate of PDLG (≈90 % weight loss in six weeks), or the stability of silk-based substrates which are capable of maintaining high accuracy after three utilizations, using different analytes (albumin, uric acid and glucose), with an minimum R2 of 0.967. The next objective of this project was to increase the versatility of the wax printing technique in terms of functional materials. Three different types of hydrophobic wax-based inks have been developed: magnetic, dielectric and conductive. Magnetic waxes (with Fe3O4 nanoparticles) exhibited an actuation capability with a deformation of ≈12 mm when a magnetic field of 105 mT was applied, and an energy harvesting aptitude with an energy density of about 9.7 mW.cm−3. Active waxes with dielectric properties (with BaTiO3 nanoparticles), exhibited optimized dielectric properties up to ε= 18 at 10 kHz. Conductive waxes (with carbon nanotubes and graphene) exhibited high electrical conductivity values (up to ≈ 2.5×10-4 S.m-1), high gauge factor (up to 11), and a pressure sensitivity of (up to 0.17 MPa-1). In order to demonstrate the technological significance of the produced materials, two μPADS systems have been developed: i) a magnetic origami system completely printed on paper suitable for the detection of infectious diseases and magnetic biomarkers; and ii) a low-power thermal actuation system, based on the printing of conductive wax composites with integrated graphene nanoplatelets (GNP), that was able to work simultaneously as a barrier and as a heater. Thus the materials developed in this thesis hold great promise for the next generation of versatile, effective and accurate PADs and μPADS. |
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