Biomedical Engineering Reference
In-Depth Information
Fig. 2.16
Built-in sensors in
the chip are capable of
creating images by mapping
electrical properties of the
medium in contact with the
chip's surface. On the
left-hand side
is an image of
beads created using this
method. On the
right-hand
side
is the same image taken
with an optical
microscope [
17
]
2.4.8
Integrating Hybrid IC/Microfluidic Chips with Other
Technologies
Hybrid integrated circuit/microfluidic chips can be integrated with other tech-
nologies to increase their ability to solve problems in point-of-care diagnostics.
Improved methods for intaking fluids - blood, urine, and chemical reagents -
from the outside environment are critical for the success of hybrid IC/microfluidic
chips. Methods to mix very small volumes of fluid are also necessary to allow
reagents to properly and fully mix with the analytes. This is a difficult problem
at small-size scales, and inspiration can be borrowed from electrowetting and
magneto-mechanical mixing techniques.
There is a strong need for more automated and sophisticated methods of pulling
fluids directly out of the environment and dispensing them as droplets on the
hybrid IC/microfluidic chip. This functionality promises to make the chip more
self-contained and independent, eliminating the need for technicians and external
syringe pumps to deliver fluids. Electrical methods of pulling droplets from fluid
reservoirs have previously been demonstrated. Electrowetting is one commonly
cited method [
33
,
46
], using electrically induced differences in the wettability of
adjacent surfaces to move and split droplets [
39
].
Mixing is an important function in microfluidic devices, significantly accel-
erating the rate and accuracy of biochemical reactions. Small fluid volumes are
