Conventional microfluidics handles liquids in a continuous fashion in
microchannels. It has been widely adopted in bioanalysis for its many advantages
including the ability to manipulate single cells. The footprint of the conventional
microfluidic chip is small. However, it requires sophisticated external control and
sensing systems to function, which limits the applications of conventional microfluidics
to the laboratory environment. For point-of-care applications in the resource-limited
environment, standalone diagnostic platforms, such as digital microfluidics-based
platforms, are more desirable. Digital microfluidics manipulates fluids in discrete
volumes in the form of droplets. In this chapter, we introduce the principle of digital
microfluidics and focus on the two main forms of digital microfluidics that are actuated
by the magnetic force and the electrowetting on dielectrics. We will discuss the
actuation mechanisms in details and compare the pros and cons of the two most
popular digital microfluidic platforms. We will also look into the applications of the
digital microfluidics in biosensing and diagnostics. Example of digital microfluidicsbased
nucleic acids, proteins and cells analysis will be deliberated with a focus on the
suitability of those assays on digital microfluidic platforms for point-of-care
applications.
Keywords: Biosensing, Digital Microfluidics, Diagnostics, DNA/RNA, EWOD,
ELISA, Magnetic Digital Microfluidics, Sample-To-Answer.
