An Introduction to the Tecan Liquid Handler: Automating Repetitive Pipette Transfers
Problem: Too much Pipetting
Imagine you’re working in a biotechnology firm and your boss comes up to you and says: “I want you to take these 200 vials full of different compounds and individually transfer 1 mL of each compound into 200 wells of a multiple well assay plate within the next few hours using a single channel pipette.” You’d probably not be very happy, to put it mildly. You’ll have fill each of the 200 wells individually, one by one, having to change your disposable dispenser tips for each dispense to avoid cross contamination. Now what if instead of 1 mL each, the dispense volume varied wildly by the compound, and instead of one plate, the compounds were to be arbitrarily distributed across multiple plates. You’d be getting pretty frustrated at your boss right about now.
Solution: Liquid Handling
This is where equipment like Tecan liquid handlers comes in. Tecan liquid handlers have been in use since the 1980s and they are one of the quintessential liquid handlers you will find used in the automation industry. They are pretty straightforward to use, and get your large scale aspirating/dispensing done without much stress involved (as long as they’re working smoothly of course!).
How does it function?
Here’s how a Tecan handler works on a basic level: It has a movable liquid handler arm with multiple dispense tips attached to it. The joints on the arm can be moved so that the tips can aspirate different compounds simultaneously. The tips aspirate the compounds needed, dispense them onto a destination like an assay plate (and the machine makes a really satisfying whirring sound as it does so), and then the tips are automatically cleaned after each dispense using some sort of cleaning solvent. This last step thankfully gets rid of the headache of changing the tips after every dispense (the tips are still replaceable in case they get clogged/broken etc). The Tecan doesn’t just transfer compounds from a vial/tube to a plate; it can also do a plate to vial transfer, a vial to vial transfer, a plate to plate transfer and it can even perform simultaneous transfers. This machine also contains a barcode scanner towards the back which it eventually uses to keep track of the compounds it is actually transferring (the vials/tubes are usually labelled with compound specific barcodes). There’s a light on the top that is green if working properly, and turns red if there’s an error, a barcode misread, or some other issue.
Operation: How to use it
Here’s a very basic overview of how the Tecan is operated. Freedom Evoware is a software developed by the Tecan company itself. This software is pretty simple to navigate and work with, yet it takes time to master. There is a lot that can be done with it, but I’ll just stick to the basics for now. I’ve posted a screenshot of the software below. On the left there is a control bar where you can find some preset programs and many options including the types of carriers to transfer from and to, scheduling the program, cleaning out tips, and a lot more. There is a script editor where you can write your program, which works like a very simplified coding language. You can write for loops, write comments, and set variables, for example. On the bottom you can choose where you want your carriers on the Tecan worktable. You can choose where you want your source compounds to come from and where you want them to end up. You can save many scripts and schedule to run them as you please.
Is it fast though?
One thing to note about the Tecan is that it isn’t particularly fast. The speed probably depends on the model and the age of the machine, but I’ve noticed that it takes about 3-4 hours to transfer compound from 384 vials into 768 tubes (each compound is split into 2 tubes). A seasoned lab veteran could probably beat the Tecan in terms of time if they both had to dispense compounds from a source to destination hundreds of times. However, just like any good automation, the point of the Tecan isn’t necessarily speed, but convenience. Once you’ve set up the Tecan and run it, you are free to do whatever else you need to in the lab instead of focusing on a repetitive task for several hours where you could easily mess up (and even a small mistake could lead to huge problem when it comes to assay plates). The Tecan may not be quick, but it is accurate and it will give you the result that you’re looking for as long as you operate it right, without all the headaches that would come with doing the techniques manually. However, if you’re working on a small scale and performing just a few transfers (say 5 or less), the Tecan might not be worth it because it will take longer just to set it up and put in operation than it will if you manually dispensed the compounds using a pipette.
Blogging about the Tecan
The Tecan truly is like an onion. Ok, so this isn’t the most eloquent of analogies, but it’s not inaccurate either. It has a lot of layers. There is so much that can be done on this one platform and I don’t think I’ve even scratched the surface, even though I work on it almost everyday. I hope to learn a lot more about the Tecan in the future and I certainly intend to write more blog posts about matters related to the Tecan liquid handler, like troubleshooting, software specifics, how to deal with its output files, and other Tecan perks. So stay tuned for more!
