“Most health clinics in rural African regions have challenges sending samples to hospitals in cities because they are typically far from them and due to the poor state of the local roads, the test tubes containing the samples regularly break as a result.” Richard Holdbrook
In order to provide health clinics in rural and isolated locations in Africa with access to a machine that can separate blood fluids and other liquids for accurate testing and diagnosis, we have constructed a microcentrifuge as a first prototype.
We are looking for laboratory experts, people who have been working with micro-centrifuges to help test our first prototype as we seek expert opinions and consultation.
I find this project is very interesting and useful. From the video I can see (and hear) that the rotor of the centrifuge is not perfectly balanced. This is, I think, a crucial point to address as it could compromise the centrifuge at high speed and not achieve the separation in the samples.
this looks nice and I think it is great that you are reaching out to get collaborators on the project.
I think one thing that could help a lot is to make your current documentation publicly available? this would allow people to make comments and suggestions in an asynchronous way, reducing the barrier to contribute!
Other than that, from the video I agree with @RosarioIac, you and your collaborators should really look into why the rotor is not balanced, even when it is running empty (seems empty in the video). With the high speeds you will get on the centrifuge, having this unbalanced also poses a safety issue.
Related: A couple of years ago I helped coordinate a couple of OSH projects as part of my fellowship with Mozilla…One of them was about making a derivative of a centrifuge… more info about it here Open Source Centrifuge | Open hardware centrifuge project
Just in case it can serve as a quick tip for solve the balancing problem; from the @gaudi designs I learned that is always much easier to produce balanced holders with laser cutting than 3D printing.
In the hackteria wiki there is some further information about different ways of making the rotors, together with some centrifuge designs using old CD readers. The laser cut rotors in the wiki are for special tubes so you may want to adapt this idea to your own eppendorfs.
I’d recommend reading the issues board for the FOSH project that Andre mentioned (Open Source Centrifuge | Open hardware centrifuge project) because the comments there contain a lot of ideas and improvements. I found them very interesting to follow at the time the project was ongoing.
For very low speed applications, I feel safe with 3D printed/laser cut centrifuges but for anything involving any amount of speed or heavier tubes (6 x 3-6 ml blood collection vacutainers is not very light) I want metal or very thick and strong plastic separating me and the rotor if it shears off the spindle. I don’t know what the speed of your motor is but some designs use quite high speed RC helicopter motors with minimal protection and it’s a bit scary. I would plan for a catastrophic mechanical failure at top speed when you’re designing the safety features!
One design aspect that you might want to look into is the fixed angle rotor, I think it is typically 45 degree for blood separation. Yours looked less than that but it could just have been the angle of the camera in the video.
There are a lot of opportunities in bio for OS but I don’t think centrifuges are. The are high speed, dangerous machines that need to be made of metal. Plenty of dangerous or not performant ones already in OS.
Better just buy used ones and fix them, I have two, they work perfectly and the were about 100$ a piece. One would need very expensive manufacturing facilities to make them.
Thank you @jcm80@amchagas@FranQuero@adrianMolecule We will take your suggestions into consideration. we will also try to properly document the entire process. @adrianMolecule I understand your concern and thank you for that, hopefully with communities like AfricaOSH & GOSH, we can come together and make a more acceptable, standardized one.
I will check out all the resources shared and I will keep everyone updated on our progress.
The are high speed, dangerous machines that need to be made of metal. Plenty of dangerous or not performant ones already in OS.
Low cost consumer 52x CD-ROM drives ran at above 10,000 RPM, were made of plastic and often mounted in desktop PC towers at about eye height. If that was possible then a low cost safe open source centrifuge is definitely possible.
Did you make any progress with this, or is the FOSH Polyfuge still the latest / best open source option?
I was looking for an open source centrifuge for PCR, my initial googling found OpenFuge with a $200 BoM back in 2013 which looked promising but the inventor’s last reply there was 10 years ago.
The presumably closed source SciSpin Fixed speed 7,000 RPM / 2,680 g micro centrifuges are available for only £90. I don’t know if they ship to Ghana, but I might be tempted to put centrifuges in the same category as autoclaves for the likes of the Open Science Shop - too dangerous if something goes wrong…
Based on my experience 3D printed devices rarely manage to withstand the high forces required in some of the devices. The centrifuges are a perfect example of that. I heard accounts of pieces flying off.
A normal centrifuge should achieve 15-20 thousands RPM at a given radius. The actual measurement is in Gforce not RPM which requires a certain radius. I have not seen any design that I would feel capable of delivering the standard Gforce. Most of the designs I expect to disintegrate. That is why industrial centrifuges are made of metal parts with huge motors. Unless you have a lathe and machining skills that is out of reach.
I made many of the lab lab devices I use but I bought centrifuges and repaired them. They are not so expensive - around 150-200$ second hand and many are OK to repair.
We had a prototype for the centrifuge, which was presented in a workshop during the Africa Makerspace Gathering in 2022 in Cape Town. After the workshop, we wanted to seek further collaborations and a peer review process since the centrifuge was still a prototype rather than the finished product. We were looking to lab experts and technicians to collaborate with on this project.
Unfortunately, the maker of this centrifuge decided to bin the project as he had to further his education in the States and couldn’t balance both at the same time. Currently, this project is on the shelves and we don’t know if it will ever move pass the prototype phase.
So I presume you didn’t manage to balance the rotor, following the comments above…?
It would be nice if we could find an open source option for everything. But when the required manufacturing methods for safe products demand economies of scale, I guess there’s a case for closed source…
Happy Christmas if you’re celebrating, happy day if not.
No we didn’t. It was part of the reason we put out a call for collaboration before the project got scraped. I could put you in touch with the lead designer if you’d be interested.
I’d be happy to be put in touch, but probably only if active development resumes, or we come across someone with the right skills and motivation to take the project on. Having someone raising safety concerns over a dormant project is unlikely to be encouraging.
For our DNA sequencing prep needs we can recommend commercially available centrifuges - either low cost microcentrifuges from the likes of Sciquip or the well documented & supported Bento Lab all-in-one solution.
Has anyone looked into the OpenCell 3-in-1 DNA extraction device? A suggested build cost of <$50 gets you a 6000 RPM, 3000g centrifuge with a bead homogeniser and a vortex mixer thrown in.
I might be interested to collaborate on something like that so please tell me more in case you are interested.
As far as I can tell the device mentioned below is very well documented. It seems to have a lot of bells and whistles.
I did not spend enough time reading the paper to understand if the claimed lab capabilities are sufficient and realistic. I believe it is or will become unusable after several usages.
I’m not a big believer in 3D printed centrifuges because they are weak, they break and take forever to print.
This might work for a bench centrifuge if proper changes would be done:
I believe a centrifuge should use rubber shock absorbers in addition to rubber legs.
I believe a vibrating device like this should never be operated from a bread board and loose wires.
I believe PLA should not be used as structural material and even more advanced materials need to be reinforced with HDPE or metal to ensure safety and durability.
In my experience most devices that are multipurpose end up being mediocre in all stated purposes.
One option for an impact absorbing wall would be to 3D print a hollow wall with a 50mm cavity and then to fill the void with cement. This should be very strong and low cost. You would need to vibrate the cement to get it to fill well.
