I-DOT: Understanding Cellink’s Single Cell Dispenser

In only six years, Eric Gatenholm, along with his co-founding partner Hector Martinez, has moved from focusing on commercializing biotechnology startups to running one of the leading companies to offer bioinks, 3D bioprinters, and other consumables for research applications in the field of 3D bioprinting. Cellink has become one of the pioneering biotechnology companies that are quickly advancing their 3D bioprinting capabilities and expanding their portfolio. In the short journey to success, Cellink has acquired other companies to escalate its development. In 2019, German biodispensing tech firm Dispendix was acquired by Cellink, adding the company’s technologies to its bioprinting solutions. Among them is Dispendix’s patented Immediate Drop on Demand Technology (I-DOT).

Thanks to a new webinar presented by Cellink‘s field application scientist Jordan Irvin, viewers are introduced to the potential behind the technology. Understanding especially how this product can be applied to a range of dispensing applications, including cell dispensing, Matrigel dispensing, array generation and more.

Designed to speed up drug testing processes, the IDOT itself was developed over 10 years at the Fraunhofer Institute, in Munich. In 2017, Dispendix launched the platform’s first commercial product, the I-DOT One, and now under the Cellink umbrella, the IDOT’s reach could be even greater.

The High-throughput Screening with the I-DOT Liquid Handler webinar delves into the features designed for optimizing non-contact liquid-handling tasks, the benefits for high-throughput screening (HTS), as well as a walk through I-DOT’s software, which optimizes protocol creation.

Irvin described how the I-DOT system uses eight individually controlled positive pressure channels to generate droplets from 8 to 50 nanoliters from a small hole at the bottom of each well, and with each channel being able to generate up to 100 droplets per second. According to the expert, one of the great advantages of the device is the tablet interface on the top that allows almost all the programming to be done on the screen.

“To interact with the device, there’s a touchscreen and only two trays to put in standard SBS style microplates. The source tray on the top has an option to have temperature control on it, which will allow dispensing materials of different types, including Matrigel. It has a destination tray on the bottom so liquid moves on a downward path and this destination tray has XY mobility so that you can cherry-pick or pool any samples from your source to the destination tray,” described Irvin.

According to the company, internally, the I-DOT has droplet verification on each one of the source wells, de-ionization control so that the droplets fly as intended to minimize static electricity, there is humidity control as an option in case the user has agents they don’t want to dehydrate, and ethernet connectivity. It also has an air filter, that requires compressed air, otherwise, a small external compressor is all that it needs.

Irvin suggests that “the I-DOT has a lot of utility in terms of high-throughput screening and other applications around that. Its great for genomics and proteomics – especially if you are trying to miniaturize reaction –; it can dispense cells, beads, and compounds [either chemical or biological]; it also allows you to do assay development, especially if you are trying to set up and miniaturize reactions it sets up lots of different possible combinations; it’s great if you are doing synthetic biology applications, and allows researchers to do a wide variety of high-thoroughput screening.”

So why does the I-DOT work well for high-throughput screenings? Irvin indicated that the positive air pressure used is non-contact, so the setup for the individual workflow is quite fast, all a user needs is a source plate and destination plate, which also eliminates carryover and minimizes the chance of cross-contamination from one sample to another.

He claims that “the volume range that can be used in the dispensing gives a lot of flexibility in terms of setting up reactions” and that “because the system uses eight individually controlled positive pressure channels to generate droplets from 8 to 50 nanoliters from a small hole at the bottom of each well, the device is quite fast, with each channel being able to generate up to 100 droplets per second.”

We learn during the webinar that one of the commanding characteristics of the I-DOT is that it has built-in droplet verification at the end of every dispensing. Irvin states that, by far, it is the only instrument in the world to incorporate bubble detection and the capability to detect when users run out of source liquid. The system’s DropDetection is a patented feature that detects and counts every droplet released during a single dispensing run. The tool uses a circuit board mounted under the I-DOT source tray that leverages 96 miniaturized light barriers to detect every droplet generated from each source plate position, identifying changes in light intensity to detect droplets as they pass the light barrier.

“Researchers can just walk up and use the I-DOT, which is one of the great benefits for high-throughput screening, giving them very fast assay setups, plus, the software doesn’t require any coding or scripting, its just a touch pad interface,” Irvin said. “All this actually cuts up the time from setups to getting into the assays, especially if you have really short time courses. It is also automation friendly, which means it works with other liquid handlers, like robotic driper arms. Moreover, it gives accuracy to users, not only because of the way the machine is designed, but from droplet verification.”

“The intuitive software streamlines your workflow and allows users to do almost everything for protocol creation on board. You can import easily a CSV files to create more complex protocols and integrates with any third-party scheduler. In the main screen it has three main groupings: wellgroups; parameters, that is liquids that are being used in those wells, and a representation of the plate or preview. Depending on the parameters set by the user, the software will do all the calculations on the spot.”

To set up a brand new protocol using the I-DOT software requires the user to define a wellgroup, add liquids and volumes that will be used, and then the software automatically does everything.

“The I-DOT has powerful software that streamlines setting up HTS protocol. Furthermore, because it is using eight independent channels and its all non-contact, the setup for the actual assay run is quick, this allows users to go back and cherry pick or pool because that destination tray is on the XY stage,” explained Irvin. “The I-DOT can dispense DNA of any concentration and type, beads, cells, liquid classes from DMSO to 50% glycerol, and even Matrigel. It is scalable so you can run multiple source and destination plates can be combined for any HTP assay. And because it has 96 possible source wells you can set up very complex DOE tests.”

Since Dispendix created the product, it has been deployed around 50 labs worldwide, and been a part of eight different publications like the Karolinska Institutet Nicola Crosetto, were they state that the I-DOT was very helpful in setting up the process and designing an entirely new workflow. The 30-minute webinar is certainly worth the time, as Irvin goes through a software overview in detail, explaining how the setup works as well as many specificities that make the software a winning feature of the device.