Desenvolvimento de dispositivos analíticos em filmes de poliéster utilizando uma plotter de recorte
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2021-02-10
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Universidade Federal de Goiás
Resumo
This study describes the development of analytical devices in polyester films coated with a
layer of ethylene-vinyl acetate (EVA) using a clipping plotter. The proposed protocol involves
the projection of the desired layout in graphic software, followed by the clipping step. After
cutting, the polyester film containing the desired structure was thermally laminated against
one or more polyester films coated with EVA. Due to the thermosensitive nature of EVA, it
was used to promote the sealing of devices. The cutting plotter made it possible to cut
channels with widths ranging from 250 to 1000 μm with good precision. However, the
manufacturing protocol allowed to obtain channels with a width > 300 μm in polyester films
with a thickness of 250 μm, since the channels with a width of 250 μm showed total blockage
due to the fusion of EVA and the penetration of this material into the channels. The
mechanical and chemical resistance of the microchannels defined in the polyester films were
evaluated. Concerning mechanical resistance, the microfluidic structure supported the
transport of fluids with a pumping rate ranging from 0 to 300 µL min 1, without leakage. The
chemical compatibility of the structure was tested with the exposure of the microchannel to
different organic solvents (such as acetone, isopropanol, ethanol, acetonitrile, and ethyl
acetate), which obtained satisfactory chemical resistance, with no leakage in the channels.
The viability of the proposed protocol was demonstrated through the manufacture of
microplates containing 96 microwells, microfluidic mixers in three-dimensional (3D)
arrangement, devices for the determination of H2O2 based on distance and electrophoretic
microsystems (MSE). As a proof of concept, the microplates were used for colorimetric tests of urea and glucose, and both showed linear behavior in the concentration ranges equal to 0-
100 mg dL-1 and 5-90 mg dL-1, respectively. The detection of limit (LOD) values obtained for
the urea and glucose assays were 7.73 mg dL-1 and 0.96 mg dL-1, respectively. The
concentrations of urea and glucose were determined in artificial samples of urine and serum,
respectively, and they corroborated with the theoretical values. The complexation reaction
involving Fe2+ and o-phenanthroline was selected as a model to investigate the viability of
the 3D microfluidic mixer. The turbulence caused by the 3D arrangement of the microchannel
induced the mixing of the solutions efficiently, exhibiting behavior similar to the reaction
carried out outside the chip. The versatility of the clipping plotter was also demonstrated with
the development of a hybrid polyester device containing a paper substrate impregnated with a
copper solution to catalyze the decomposition of H2O2. The gas released in the reaction was
used to promote the displacement of a dye plug. Thus, the distance covered by the plug was
proportional to the concentration of H2O2 in the concentration range between 117.5 and
587.5 mmol L-1, obtaining an LOD of 65.22 mmol L-1. The MSE was tested using a model
mixture containing K+, Na+, and Li+. Due to the limiting dimensions (width), the preliminary
results showed low separation efficiency, which can be improved by decreasing the width of
the channels by customizing the cutter blade. Considering the results obtained, it is concluded
that the proposed method presented simplicity and speed (< 10 min) for the development of
low-cost analytical devices (<R$ 0.45) and can be implemented in laboratories and research
centers using alternative and affordable instrumentation.
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Citação
MOREIRA, N. S. Desenvolvimento de dispositivos analíticos em filmes de poliéster utilizando uma plotter de recorte. 2021. 114 f. Dissertação (Mestrado em Química) - Universidade Federal de Goiás, Goiânia, 2021.