Also, wowza, it pains me to see non-metric units used there. One would have thought that fields that are so deeply academic in nature would be free of imperial units!
https://darwin-microfluidics.com/products/nanoport-kit-for-1...
It’s not so micro really. The internal flow geometry is around 100um but you’re mostly working with 1.6mm (1/16”) tubing that’s easily handled and used with all these fittings. The fittings are all finger tightening and a lot of the prefabricated chips are easily clamped into manifolds. You can also be creative and use heat shrink to connect tubes and the aforementioned PDMS punching works well, you just leave a large (2mm) region at the start and end of a micro channel to punch before you bond your PDMS to a glass microscope slide.
You’re never really exposing the flow geometry outside the clean room. It’s much like working with an IC on a breadboard, once it’s made you can wire it up easily and not really worry about anything mechanical other than the device working.
Yes, the imperial measurements for fittings is a pain.
My biggest complaint about microfluidics is that the design of the circuits is very ad-hoc. Since the flow rate is typically creeping flow the assumption is that the flow physics are extremely simple so we see these basic linear designs, dramatically different to microfluidic flows we see in biology. People just draw basic shapes on CAD that are easy to fabricate and iterate until the decide works.
I’ve submitted an ERC proposal to take a more computational approach to the design and layout of microfluidic devices. Instead of designing the exact layout of the device geometry the designer expresses their intent for its function, as a circuit diagram or node workflow and we then use various methods (such as numerical simulation and optimisation) to construct the geometry. I guess it’s not too dissimilar to automated PCB layout.
Your inclination toward a computational approach makes me think of what folks in mechanical engineering are up to these days. Creating mechanical designs generatively with topological optimization (https://all3dp.com/2/topology-optimization-simply-explained/). There appear to be clear use-cases and advantages: you reduce the amount of material needed, decide exactly what stress points you want to focus on and work to strengthen those particular parts of the structure in interesting ways, etc. Fluid mechanics is a little more complicated though I think, so you're certainly up for a challenge!
I wish you success with your proposal, and I hope to discover your findings published in a nature paper on the frontpage of HN sometime soon ;).
I’m interested in this approach because the current situation (including hybrid) has engineers, often students, designing devices to meet the need of biologists. There a going to be a fundamental challenge here in terms of communication of requirements, expertise and time the engineers have and limitations of available fabrication methods.
This results in the lowest common denominator in terms of design and performance. I want to make tools that the key stakeholders (biologists etc) can use to plot out the functionality they require and obtain a functional geometry. I’ve also got a concept for a rapid prototyping platform that eliminates many of the problems with 3D printing.
