One foot in the toy box (Day 126)
30th September 2014
In my daily blog, I've talked frequently about the need for chemical engineers to operate in multi-disciplinary teams. Today's blog - about an innovation in 3-D microfluidic systems - illustrates this point once again.
The idea for a new type of 3-D microfluidic system, developed by USC Viterbi School of Engineering, has great similarities with a toy box favourite - Lego, which as boys and girls know, is a fun and flexible system that can be used to build (and deconstruct) just about anything.
USC's system can be built, quickly and cheaply, by simply snapping together small modules by hand, just like lego.
Microfluidic systems are used in many fields including engineering, chemistry and biotechnology to precisely manipulate small volumes of fluids for use in applications such as enzymatic or DNA analysis, pathogen detection, clinical diagnostic testing, and synthetic chemistry.
Traditionally, microfluidic devices are built in a cleanroom on a two-dimensional surface using the same technology developed to produce integrated circuits for the electronics industry.
Though tiny, designing, assembling and testing a new microfluidics system can take a lot of time and money. Building a single device can often require multiple iterations, each of which can take up to two weeks and several thousand dollars to manufacture. And the more complex the system, the higher the number of iterations needed.
The system borrows an approach from the electronics industry, which uses prototype boards to build circuits.
The researchers conceived of three-dimensional modular components that encapsulated the common elements of microfluidic systems, as well as a connector that could join the separate components together.
One of USC Viterbi's research team includes chemical engineering and materials science professor, Noah Malmstadt.
Together with Krisna Bhargava, who conceived of the idea, and other colleagues, the team were inspired by recent advancements in micron-scale 3-D printing to design computer models for eight modular fluidic and instrumentation components (MFICs, pronounced “em-fix”) that would each perform a simple operation.
Examples are a “helix” component that can mix two fluid streams and a component that contains an integrated optical sensor for measuring the size of small droplets. The components constructed for this study are approximately 1 cm3, slightly smaller than a standard 6-sided die. The MFICs can be assembled, broken apart, and re-assembled quickly and easily.
Noah says: "What we’ve built looks more like a hobby breadboard. You can build a circuit on the cheap with your bare hands.”
Using the 3-D-printed MFICs, in a matter of hours the team was able to build and test a device that mixed fluids using a helix component and turned the mixture into droplets.
Essentially a very long track packed into the same standardized module footprint, the helix component allows adjustments in flow resistance or can serve as an efficient mixer. In microfluidic systems, mixing is dominated by diffusion, and a complex helix can speed up the process by folding the fluid onto itself.
Noah explains: “Trying to control how things mix has always been a major issue in this field just due to the way that fluids flow at very small dimensions.
“People have come up with all sorts of ways to twist and turn the channels to try to improve the mixing. The fact that we can do it in three dimensions with this 3-D helix really simplifies things.”
The result is an extremely cheap, standardized, easy-to-use set of components that can quickly be assembled and re-assembled into a microfluidic system for a mere fraction of the time and cost it currently takes to produce a device to perform the same operation.
“People have done great things with microfluidics technology, but these modular components require a lot less expertise to design and build a system,” said Noah.
“A move toward standardisation will mean more people will use it, and the more you increase the size of the community, the better the tools will become.”
I think the team at USC should be very proud of their achievement and an excuse for all of us to keep one foot firmly planted in our toy boxes where fertile imaginations are always free to explore.