Desenvolvimento de tecnologias alternativas para fabricação de dispositivos microfluídicos em papel
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Data
2014-12-12
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Universidade Federal de Goiás
Resumo
This current study describes the development of alternative technologies for
the fabrication of microfluidic paper-based analytical devices (μPADs). The
first technology refers to the manufacturing of a metal stamp for rapid
prototyping of μPADs. Basically, the method uses the heating process to
transfer wax to the paper surface. The wax is required to create a
hydrophobic barriers thus delimiting microfluidic channels for the fluid
transport through lateral flow effect. Some remarkable advantages of the
metal stamping process include robustness, portability and simplicity.
Paraffin is a hydrophobic and thermoplastic material that can be easily
molded. Furthermore, it shows high chemical resistance when exposed to
different aqueous and organic solutions. The stamping-based technology
allows the fabrication of μPADs at very low cost. The proposed approach
exhibited great reproducibility. The relative standard deviation (RSD) for the
channel widths measured on 50 independent μPADs revealed a value of
3.5%. The analytical performance of the paper-based device associated with
colorimetric detection was tested for the nitrite analysis in clinical, food and
environmental samples. The limit of detection (LD) nitrite assays without preconcentration
was 11.3 μM. In order to access the nitrite concentration in
environmental samples, a preconcentration method was developed allowing
to achieve a LD of 5.6 μM. The results obtained were compared to the
spectrophotometric technique and the statistical test demonstrated no
significant difference between both methodologies. The stamping process
have demonstrated high potential to produce μPADs in laboratories with
none or minimal instrumentation. Besides the stamping process, another
fabrication approach based on the spraying of white glue mixed with a
sensitizing agent was also proposed to produce μPADs. To create effective
hydrophobic barriers, the white glue was first sprayed on the paper surface
though a magnetic mask. Afterwards, the device was exposed to visible light
for polymerization of the glue. In order to evaluate the fabrication
methodology, 25 devices were produced and the RSD value achieved for the
channel widths was 5.7%. The analytical feasibility of the μPADs fabricated
with white glue was successfully demonstrated for qualitative assays
dedicated to urinalysis (glucose, uric acid, nitrite, pH, BSA, urea, ketones
bodies and bilirubin) and pancreatitis assay (amylase and lipase). Both
alternative methods based on stamping and spraying has exhibited great
potential to be used for production in mass. Moreover, the proposed devices
revealed high potential to be broadly explored in biological/clinical, food and
environmental applications.
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CARDOSO, T. M. G. Desenvolvimento de tecnologias alternativas para fabricação de dispositivos microfluídicos em papel. 2014. 80 f. Dissertação (Mestrado em Química) - Universidade Federal de Goiás, Goiânia, 2015.