2 Bio-microelectromechanical Systems (BioMEMS) …
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colored substance, light wavelengths are absorbed in different proportions (Fuwa and
Vallee 1963). The intensity of the resultant color will be proportional to the concentration of the measured analyte and the amount of absorbed light will be proportional
to the intensity of the color (Ricci et al. 1994).
Colorimetric analysis is applicable to detect the presence of organic and inorganic compounds, making it a suitable option for biosensors. Some applications
for colorimetric detection devices include hand-held bio-diagnostics, point-of-care
diagnostics, and naked-eye detection. Current chapter focuses on the fabrication
of microfluidic, paper-based, or polymer-based platforms based on this common
detection strategy.
2.3 Recent Advances of Colorimetric Detection
in Paper-Based BioMEMS
One of the major problems in healthcare nowadays is accessibility. Many people
worldwide have limited to no access to laboratories or hospitals, hence, in order to
reach these communities, smaller portable devices with the same accuracy are needed.
Among these developments, the paper-based analytical devices (PAD) attract a great
deal of attention. PAD devices have proven to be the inexpensive, simple, portable,
and disposable. Likewise, they are easy to use, make complicated readout equipment
unnecessary, and produce semi quantitative results (Teengam et al. 2017) in a short
amount of time (Murdock et al. 2013). For that reason, PADs are being used to
diagnose diseases via DNA and/or RNA recognition (Teengam et al. 2017), monitor
human activity (Murdock et al. 2013), detect nucleic acids (Choi 2016), sense pH
in sweat and/or saliva (Oncescu et al. 2013), and recognize cholinesterase inhibitors
(Matˇ ejovský and Pitschmann 2018), thus, making such devices favorable for a wide
range of applications including medical (Teengam et al. 2017), military (Murdock
et al. 2013), nutrition (Choi 2016), biochemical (Oncescu et al. 2013), and nerve
chemical warfare (Matˇ ejovský and Pitschmann 2018). Below, several examples of
PADs are presented with a specific focus on biosensing application.
In addition to the previously stated benefits of paper-based devices, μPADs
enhance point of care for detecting diseases (Sanjay et al. 2016), biomolecules (Li
et al. 2018; Gabriel et al. 2017), and antibiotics (Nilghaz and Lu 2019). They offer
inexpensive, simple, eco-friendly, portable and quick bioanalysis (Nilghaz and Lu
2019). Additionally, due to their small size, these devices provide a greater surface
to volume ratio, improving the immobilization of proteins through processes such
as enzymelinked immunosorbent assay (ELISA) integrated into this platform, and
other biological agents (Sanjay et al. 2016). Many variations and additions can be
made to μPADs in order to enhance its properties. For example, cotton, being a
similar material to paper and providing the same advantages as well as being stronger
and more durable, becomes an option for embedding into daily wearable products
(Nilghaz et al. 2015). Also, by using chemical vapor deposition (CVD) instead of
37
colored substance, light wavelengths are absorbed in different proportions (Fuwa and
Vallee 1963). The intensity of the resultant color will be proportional to the concentration of the measured analyte and the amount of absorbed light will be proportional
to the intensity of the color (Ricci et al. 1994).
Colorimetric analysis is applicable to detect the presence of organic and inorganic compounds, making it a suitable option for biosensors. Some applications
for colorimetric detection devices include hand-held bio-diagnostics, point-of-care
diagnostics, and naked-eye detection. Current chapter focuses on the fabrication
of microfluidic, paper-based, or polymer-based platforms based on this common
detection strategy.
2.3 Recent Advances of Colorimetric Detection
in Paper-Based BioMEMS
One of the major problems in healthcare nowadays is accessibility. Many people
worldwide have limited to no access to laboratories or hospitals, hence, in order to
reach these communities, smaller portable devices with the same accuracy are needed.
Among these developments, the paper-based analytical devices (PAD) attract a great
deal of attention. PAD devices have proven to be the inexpensive, simple, portable,
and disposable. Likewise, they are easy to use, make complicated readout equipment
unnecessary, and produce semi quantitative results (Teengam et al. 2017) in a short
amount of time (Murdock et al. 2013). For that reason, PADs are being used to
diagnose diseases via DNA and/or RNA recognition (Teengam et al. 2017), monitor
human activity (Murdock et al. 2013), detect nucleic acids (Choi 2016), sense pH
in sweat and/or saliva (Oncescu et al. 2013), and recognize cholinesterase inhibitors
(Matˇ ejovský and Pitschmann 2018), thus, making such devices favorable for a wide
range of applications including medical (Teengam et al. 2017), military (Murdock
et al. 2013), nutrition (Choi 2016), biochemical (Oncescu et al. 2013), and nerve
chemical warfare (Matˇ ejovský and Pitschmann 2018). Below, several examples of
PADs are presented with a specific focus on biosensing application.
In addition to the previously stated benefits of paper-based devices, μPADs
enhance point of care for detecting diseases (Sanjay et al. 2016), biomolecules (Li
et al. 2018; Gabriel et al. 2017), and antibiotics (Nilghaz and Lu 2019). They offer
inexpensive, simple, eco-friendly, portable and quick bioanalysis (Nilghaz and Lu
2019). Additionally, due to their small size, these devices provide a greater surface
to volume ratio, improving the immobilization of proteins through processes such
as enzymelinked immunosorbent assay (ELISA) integrated into this platform, and
other biological agents (Sanjay et al. 2016). Many variations and additions can be
made to μPADs in order to enhance its properties. For example, cotton, being a
similar material to paper and providing the same advantages as well as being stronger
and more durable, becomes an option for embedding into daily wearable products
(Nilghaz et al. 2015). Also, by using chemical vapor deposition (CVD) instead of