Put The Power Of PCR In Your Pocket With This Open-Source Thermal Cycler

When the first thermal cyclers for the polymerase chain reaction came out in the 1980s, they were as expensive as a market driven by grant money could make them. Things haven’t got much better over the years, largely shutting STEM classes and biohackers out of the PCR market. That may be about to change, though, if the €99.00 PocketPCR thermal cycler takes hold.

PCR amplifies DNA in a three-step process: denaturation, which melts double-stranded DNA into single strands; annealing, which lets small pieces of primer DNA bind to either side of the region of interest; and elongation, where the enzyme DNA polymerase zips along the single strands starting at the primer to replicate the DNA. The cycle repeats and copies of the original DNA accumulate exponentially. Like any thermal cycler, [Urs Gaudenz]’s PocketPCR automates those temperature shifts, using a combination of PCB-mounted heating elements and a cooling fan. The coils rapidly heat a reaction block up to the 99°C denaturation temperature, the fan brings that down to the 68°C needed for annealing, and then the temperature ramps back up to 72°C  for elongation with thermostable DNA polymerase. PID loops keep the reaction temperature precisely controlled. The whole thing is, as the name suggests, small enough to fit in a pocket, and can either be purchased in kit form or scratch-built from the build files on GitHub.

We applaud [Urs]’ efforts to get the power of PCR into the hands of citizen scientists. Quick and dirty thermal cyclers are one thing, but Pocket PCR has a great fit and finish that makes it more accessible.

Thanks to [Abe Tusk] for the tip.

19 thoughts on “Put The Power Of PCR In Your Pocket With This Open-Source Thermal Cycler

    1. Step 1: Cut genes out of a larger stretch of DNA (like a genome) with restriction enzymes or something.

      Step 2: Isolate the DNA you want by size using gel electrophoresis.

      Step 3: Use PCR to make lots of copies of the gene or DNA that you are interested in.

      Step 4: Use your DNA for research or development. Maybe you want to play with CRISPR or stick a gene into a plasmid or viral vector or something, and now you have enough of the DNA to do that.

      The only problem is that you still need ‘primers’ for the PCR process to work, and those are bespoke stretches of a few dozen base pairs which you still need to order from large companies who aren’t usually thrilled to work with tiny-volume individuals. The perishable materials also add up, and you’ll want other equipment like -20C and -80C freezers. Biology is hard.

      1. Is that really likely to work though? I was under the impression that loose DNA strands were rather fragile in the environment if not in a favorable medium or embedded in something, like a skin flake or hair root etc.

  1. Great project! A few years ago I was stuck using an unreliable thermal cycler because repairing/replacing it was too expensive. I’m sure that many have had this experience; lower-cost thermal cyclers are an important contribution to science.

    I hate to say anything negative about such a good project, but I’m slightly concerned about the exposed circuitry. When I was in a biochem lab, we’d occasionally need to wipe down a lot of the surfaces, ex. if something really nasty spilled. It would be difficult to wipe this machine. And an unlucky spill could probably short out the machine.

    OTOH, none of my builds enclose all the circuitry, so my comment is probably quite hypocritical. Regardless of this, I’m very impressed by the project.

  2. I’m always amazed that anybody thinks science can be accomplished with closed source hardware. I mean, a broken clock is right twice a day, and I’m sure a lot of science is accurate, but without being able to know how your instruments work, there is an unavoidable degree of uncertainty.

  3. I am disappointed. This looks nothing at all like the most common consumer thermocycler, the E-Z Bake Oven. Frankly, a thermostat set up to control the bulb (or heating element in more modern designs) would be pretty awesome, honestly.

  4. why does everyone always take a huge shortcut and assume thermocycler==pcr seriously that pisses me off. open source effort are just to make home lab equipment cheaper but a thermocycler is hardly the largest hurdle for biohackers that want to play with DNA.

      1. short answer: the biggest hurdle would be getting all the supply and set up a lab where you can work with DNA/RNA.

        long answer: most company that sell chemical supplies usually don’t sell small quantities so unless you need a few 100 gram to kilos at once your out of luck. also the vast majority of those companies don’t sell to individuals, only to company so unless you own your own company good luck getting supplies. this is especially true for biotech/lifescience stuff like enzymes, oligonucleotides and primers. the only way to get those things in small quantities and easily is to use biohacker friendly company like the ODIN. the problem there is that you can usually only buy kits that do only one thing so not really useful for actual citizen scientists.
        if by any miracle you managed to gather all you need you still need to setup a lab that is very clean an keep it that way. think of PCR product as “concentrated” DNA even minor spills or cross contamination can potentially be catastrophic ( to you experiment at least not to you health if you do it right). not to mention the nagging little problem of RNase and DNase that are almost ubiquitous everywhere.

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