The term Microfluidics touches on pretty much all walks of engineering and science. Unlike most interpretations which relate Microfluidics to the tiny amount of fluid it handles, a better description is to define microfluidic devices by their micron-level features size. The feature size, such as channel width, could range from few microns to a millimeter. On the contrary, the fluid range which is handled in Microfluidics is quite open, between nanoliter to milliliter; a one million fold difference.
There aren’t many types of Microfluidics. The most popular is continuous flow microfluidics where one or several liquid flow into a microfluidic device, get processed, then exist. The exiting fluid could be either a product or waste. Another type of microfluidics is digital microfluidics. In this type, the liquid which is usually in the form of droplets move on a surface, often by means of electrical field gradient. This category is called digital because fluid is digitized to different or same size droplets. We also encounter another type called paper microfluidics. In paper microfluidics the fluid is absorbed on one end of a paper strip and travels to the other end. During this travel the fluid is analyzed and visualized. Lateral flow test strips, similar to pregnancy test kits, are the obvious examples of paper microfluidics. Two phase-microfluidics could also be a separate type which is seeing recent surge in popularity. In the two-phase microfluidics, two immiscible fluid such as oil and water travel through a continuous network of microchannels. The most famous applications are digital PCR, and also droplet microfluidics.
Although simple in principle there are hundreds of Microfluidics application areas and thousands of microfluidic chip designs. This widespread usage is because almost any bench top conventional experiment can be miniaturized as a microfluidics-based lab on a chip test. From underground research to space and whatever in between, Microfluidics can be used. Evidence to this comes from Oil and gas industry where behavior of crude oil and salt water through porous media is studied, all the way to the examination of micro-gravity in the international space station. Biology, however, is the largest client of Microfluidics. From drug research to drug delivery. From antibody research to antigen detection. From human-on-a-chip, to fertility aid. From gene sequencing to gene delivery. From C-elegans microenvironment to marine environment. From lysis of single cells, to 3D printing of artificial organs. And much more.
Microfluidics has opened many new doors to experimental science and engineering. Here in simple language we describe what it is, how Microfluidics is fabricated, and how it is used.
What is a microfluidic chip, and how it is fabricated? There are many materials for manufacture of microfluidic chips.