Automated 96-channel micropipette project & Crowdfunding campaing

Hi everyone!

We applied to the low-cost tools for science challenge with an ambitious project: creating a 96-channel micropipette for lab robots, by repurposing Edwin’s (@EdwinHwu) piezo actuators: Low-Cost, Open-Source XYZ Nanopositioner for High-Precision Analytical Applications

The E foundation has supported the project to 85% of the goal, and we’re only missing about 1000 USD to get started. This is an all-or-nothing campaign, so we’d like to ask for advice on where to look for funders, and also for help spreading it around.

The campaign is on over here: Understanding yeast decision making processes in real time through open-source lab automation | Experiment

In principle we’d be testing the device as a pipetting and colony-arraying tool, for yeastly :mushroom: experiments, but we expect it to be reusable for a wider range of applications.

Our current pipette (as funded by GOSH’s CDP) is single channel, and quite bulky. By replacing the motor and leadscrew with piezo actuators we’ll miniaturize the pipette, and build a multi-channel version for higher-throughput lab automation; both open and on the cheap.

You are all welcome to join the fun in any way you’d like. :robot:

@gcorthey and yours truly


so cool! shall support! i still don’t quite understand how the piezo nanoscale linear actuating works!? Is this something that would be useful in Openflexure microscope stuff? @julianstirling


A standard piezoelectric actuator is a little ceramic. You apply a high voltage (100V or so) to it and it changes in size a teeny tiny amount. They are very good for ultra-fine nano-fine positioning. You can make them in fun geometries to scan in x, y, and z.

However normally their translation is limited to about 1um or so. This is where the linear actuators come in. When I used to build these for scanning probe microscopes back when I worked in Nottingham we called them slip-stick motors. They work on a similar principle to the fancy trick where you pull a table cloth out fast and everything stays on the table.

Basically you make a stage that moves along some guide rails. The guide rails should be very smooth and hard. You want a fair clamping force between the two so it takes a fair push to move the stage along the rails. Attach the rails to your little piezoelectric actuator. You can now wobble the rails back and forth by a couple of microns.

Not the clever bit! Ramp the voltage from 0 to 100V slowly. The rails move about 1 micron, and the stage is attached and moves with it. Then as fast as you can ramp the voltage back down to 0. The rails move super fast slipping under the stage and the stage stays where it was. This is cool because you can now ramp the voltage from 0 to 100V slowly again moving it another micron. Then fast back leaving it where it is.

By applying a high saw-tooth signal to the rails you can move the stage all the way along them in tiny steps. You can also adjust the steps size, or make small movements.

We used to build 3 of them that sat on each-other for motion in all directions. You can even make ones with little legs that walk over ramps.

Is this what we need for OpenFlexure

The beauty of OpenFlexure is that the components are super cheap, and that the whole x/y/z mechanism prints in one part. This means we also have sub-micron steps due to the lever reduction in the flexures and the geared down motors, but it means that it significantly reduces assembly complexity which is so essential in our goal of wide production.

The downsize of the OpenFlexure mechanism is limited range of travel, and slow speeds. But for a 100x objective scanning it is pretty well optimised. Where OpenFlexure falls into problems is when you have lower magnification and want to move a bigger thing, faster and further. In this case we probably want to look less towards piezos and more towards 3D printer mechanisms. This is something that Niamh Burke has been doing with a microscope head that is hot-swappable with the hot end of a Ender 3D printer.

Using this for a syringe pump

It is an interesting idea to use these for a syringe pump. @naikymen, have you done any first tests?

My initial thought is that the slipstick motion relies on static friction perpendicular to the direction of motion, significant forces parallel to the motion are problematic. I have only ever used piezo actuators for positioning, never to impart a force on something else.

Parallel forces are not insurmountable, you can build an actuator that moves vertically (so gravity is parallel), but you need to be much more controlled over the clamping to make it work. What sort of volumes are you trying to shift and what speed? I would guess low volumes at low speed will be fine because the pressure will equalise.

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Super cool! Thanks for rhe great explanation @julianstirling

Hiii its great reading you both!

Thanks for the awesome explanation Julian, I’ll certainly link to it. :slight_smile:

Hmm not quite on syringe pumps, the application in mind is on micropipettes.

This is exactly the main point of concern, though it sounds feasible from my (non-expert) reading of Edwin’s paper. We expect it to work because micropipettes have narrow pistons with low friction seals.

I was hoping to also have his feedback and design ideas on this point. It’s good to know that others have experimented with this too:) I’ll be writing back soon heheh.

Ideally up to 1000 uL, realistically up to 200 uL, but anything over 50 uL will do.

This is what typical micropioettes handle, and also near what fits in standard well plates.

Would about 10 mm/s be a realistic speed?

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Yaaay! The Pollination project gives out a $1k grant every day. I’ve gotten this grant before and it was a bit more reporting than I think was called for but not too bad in the end.


That seems like a reasonable speed from memory, depends on a number of design factors though. A few mm per second. That will require a fairly high-frequency, high-voltage source. There should be very little current, so make sure you scale back the current limit for safety!!

OK. that sounds like it could be achieved…

It’s been a while, but I am happy to help where I can. :gosh:


Same here! :slight_smile:

Yessss! :partying_face:

This is great Juul thanks again!

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