2 Bio-microelectromechanical Systems (BioMEMS) …
53
Fig. 2.13 Process of CuFe 2 O 4 /GQDs formation (Mao et al. 2017)
CuFe 2 O 4 /GQDs (Fig. 2.13). ACh was inhibited as the organophosphate pesticides
(OPs) concentration increased, hence reducing the production of H 2 O 2 and thus,
provoking a weak color reaction and absorbance. Therefore, it was concluded that
the absorbance is inversely proportional to the concentration of OPs.
Another example is a novel biosensor that uses gold nanoparticles to detect the
concentration of E. coli O157:H7 equipped with an app for color monitoring (Zheng
et al. 2019). The microfluidic chips have proven to detect foodborne pathogens rapidly
due to its precise control of the fluids, few sampling, and decreased detection time.
For the E. coli-detecting biosensor, shown in Fig. 2.14, the 3D printed, and surface
plasma-bonded microfluidic chip was the most important piece. The mold of the
chip was placed in 5% NaOH for half an hour and later mixed with curing agent at
a ratio of 10:1. It was placed into the mold for 12 h at 65 °C and once peeled, it
was united with the glass slide through surface plasmon treatment. It had two 600 ×
100 μm serpentine mixing channels, where one is to mix the bacterial sample with
the MNPs and polystyrene (PS) microspheres, and the other for mixing catalysate
with the AuNPs and cross-linking agents. The COMSOL platform was used in these
channels to stimulate them based on free triangular grid and finite volume. The chip
53
Fig. 2.13 Process of CuFe 2 O 4 /GQDs formation (Mao et al. 2017)
CuFe 2 O 4 /GQDs (Fig. 2.13). ACh was inhibited as the organophosphate pesticides
(OPs) concentration increased, hence reducing the production of H 2 O 2 and thus,
provoking a weak color reaction and absorbance. Therefore, it was concluded that
the absorbance is inversely proportional to the concentration of OPs.
Another example is a novel biosensor that uses gold nanoparticles to detect the
concentration of E. coli O157:H7 equipped with an app for color monitoring (Zheng
et al. 2019). The microfluidic chips have proven to detect foodborne pathogens rapidly
due to its precise control of the fluids, few sampling, and decreased detection time.
For the E. coli-detecting biosensor, shown in Fig. 2.14, the 3D printed, and surface
plasma-bonded microfluidic chip was the most important piece. The mold of the
chip was placed in 5% NaOH for half an hour and later mixed with curing agent at
a ratio of 10:1. It was placed into the mold for 12 h at 65 °C and once peeled, it
was united with the glass slide through surface plasmon treatment. It had two 600 ×
100 μm serpentine mixing channels, where one is to mix the bacterial sample with
the MNPs and polystyrene (PS) microspheres, and the other for mixing catalysate
with the AuNPs and cross-linking agents. The COMSOL platform was used in these
channels to stimulate them based on free triangular grid and finite volume. The chip