A careful reader may have noticed that we’ve been posting a lot of stories about microfluidics. We’ve talked about the possible use of new sugar scaffolds in microfluidics, EU funding for microfluidics commercialization, using desktop 3D printers to make microfluidic devices, using LEGO and 3D printers in microfluidics, heart on a chip technology, Femtoprint glass molds for microfluidics, developing an SLA printer for microfluidics and much more. So why exactly are we paying so much attention to microfluidics? Why is there so much overlap between 3D printing and microfluidics? And for most of us the real question will be, WTF is microfluidics?
In microfluidics, liquids move through small channels in a controlled way. The channels are sometimes a millimeter thick and may be only a few microns or more. At this scale a microfluidic device lets you mix, change and test liquids with pumps and valves or capillary effects. Microfluidics lets you run an experiment on a credit card sized microfluidic device. Usually, this device will have small channels with a specific design and geometry for that one experiment or type of experiments. This experiment may be faster and will require significantly less reagent than if you had to do it in the old way. You can also design your microfluidic device in such a way as to conduct a lot of experiments in parallel.
Microfluidics can, therefore, make a lot of testing, experimentation and chemical reactions much cheaper and quicker. The media (including us!) gets the most excited by things such as “heart on a chip.” With “lab on a chip”, kidney on a chip etc.; a microfluidic device simulates the conditions of a heart so well that you can experiment on it rather than an actual heart. So rather than do one expensive experiment on an actual heart or a pigs heart we do a million experiments on hearts on a chip. Imagine the cost savings and the possibilities for drugmakers and doctors? We could try “The Human Pathology” project to see what substances kill us or in a “brute force” way crack diseases by simply trying thousands or millions of substances more or less randomly. And don’t knock random, Penicillin was discovered by accident as well. Microfluidics could completely change how drug discovery is done.
Greatly advancing medical testing in this way would be enough breakthrough for many technologies but microfluidics wants more. Because if I can make teeny tiny smoothies measured in the microliters (millionth of a liter) then I can do lots of other reactions as well. At the microscale high performance, optical devices can be made through microfluidics, personalized batches of medicine can be mixed up (perhaps in the body!, lab on a pill?), inexpensive medical tests can be made for all sorts of ailments and we could have very localized and controlled chemical reactions (eg batteries for soft robots or nanobots). Like 3D printing and the laser, microfluidics is one of those change everything technologies. If we develop the devices to design, make, power and use microfluidic devices than many things will change, so many that we can not tell what effects this will have. Ultimately a dream would be a kind of Universal Microfluidic Device that could change its channels at will to do many different experiments or just the methods to industrialize the manufacturing of microfluidic devices so that it becomes very inexpensive. Right now these devices are very custom and made through many different manufacturing technologies.
This is where 3D printing comes in. You see until now these poor sods wanted to change the world using only two dimensions. Everything was etched or cut into an enclosed device with the limits of two-dimensional manufacturing. Moreover, a lot of microfluidic devices have to be completely enclosed, so they were very limited in how they could make microfluidic devices and had very limited design freedom. As we know, if you build up and object layer by layer like 3D printing does you can make many more geometries. Technologies such as femtoprint, nanoprinting and Direct Write so very exciting. Stereolithography, inkjet, and DLP can also be used for making microfluidic devices. Indeed inkjet can be used to make the channels themselves and it would be interesting to see inkjet as a possible technology for depositing liquid and making changeable microfluidic channels. If one could rearrange existing channels or just erase them easily and then print a new one then one single testing machine could do many different experiments.
Even if we could not develop this then the design freedom given to microfluidics through 3D printing should have considerable impact for them. By expanding the makable and making it easier to construct microfluidic devices then we are positioning ourselves as the logical manufacturing technology for microfluidics. There are a great number of etching and micro milling like technologies out there that can make many types of channels, often with greater accuracy than 3D printing can. If we, however, start seeing the possibilities in blocks with tens of thousands of channels in them then 3D printing can perhaps be adopted there. For now, we are probably one of the most accessible manufacturing technologies for many university labs. I would, therefore, expect microfluidics research using 3D printing to greatly expand over the coming months as people try to make devices with the technologies available to them. The beauty of 3D printing is also that it is an “experiment replication” technology so if you would print a microfluidic device on a Fomlabs using Clear Resin at a particular set of settings then I should be able to replicate your experiment with ease.
It’s unclear what the access to 3D printing would mean for the performance of microfluidics. Many papers are being written on 3D printing and microfluidics and many things are being tested out. At the moment consensus seems to be that 3D printing will be a more rapid way of making devices than the traditional PDMS method. It seems like 3D printing is moving steadily forward in being adopted. Over the past few months, we’re seeing that about ten to fifteen papers are being published every month where 3D printing is being used to make microfluidics. This is a nice clip and should build up some good academic inertia on our side. I’m very excited and interested in the confluence of microfluidics and 3D printing. I really think that this coupled with soft robotics and nanomanufacturing could change our world in immeasurable and fundamental ways. This is going to sound farfetched, but I think that the melt pool of microfluidics, nanomanufacturing, soft robotics and 3D printing will lead to us having the world on a chip.