Affordable digital dispensing for dose-response studies

Gilson and Funai have launched the Gilson Digital Dispenser, an innovative non-contact dispenser capable of dispensing dimethyl sulfoxide (DMSO) and aqueous solutions with surfactant from picoliter to microliter. The large dynamic range makes it ideal for dose-response studies, serial dilutions, and assay miniaturization.

In this free on-demand SelectScience^® webinar, Dr. Melissa Martowicz, Product Manager at Gilson, and Stefanyda Maslova, Staff Bioscience Engineer at Funai, will demonstrate the functionality of the Gilson DISPENSMAN^® with a cell-based assay. HEK 293 cells were dosed with doxorubicin from 0.00032 to 10 µm concentrations, and viability at 48 hours was quantified using Promega CellTiter-Glo^® Luminescent Cell Viability Assay.

Key learning objectives

• Explore affordable digital dispensing solutions from Gilson and Funai
• Discover how these dispensing solutions can be used within a cell-based assay

Read on for highlights from the live Q&A session, or watch the webinar on-demand, at a time that suits you.

Can I use 384-well plates?

MM: Yes, currently it's configured to run with standard 96- and 384-well plates.

Are the cartridges reusable and autoclavable?

SM: We don't prevent you from reusing the channels as some other dispensers do. However, we only validate them for a set volume of fluid, and we can't guarantee good results after that. The set volume is still being determined and will vary by fluids. However, it's going to be about 1 to 2 mL. I would not autoclave these cartridges as they're plastic.

How many times can the cartridges be reused and how can they be cleaned between uses?

SM: We can guarantee it for a certain amount of volume of fluid through the channels versus how many times it’s used. I would suggest that you don't reuse it after about one day. Outside of that, we can't guarantee the results if you use it every day.

How long does it take to fill a 96-well plate with 0.5-µL wells?

SM: That is dependent on the fluid. For DMSO, it takes about 3 minutes and 10 seconds, and for aqueous fluids with surfactant about 2 minutes and 7 seconds.

For your dose-response studies, when such a small volume of drug is added does the machine have a mixing step?

SM: The machine does not mix for you, you will need to use a shaker or a vortex. However, one benefit of our system is that it dispenses small drops across the whole surface area of the well. You should have a good, even distribution because of that, as it doesn't dispense in just one spot.

Can you do a sequential add, such as adding compound in substrates first, then going back and adding enzyme across the entire plate?

MM: The instrument currently dispenses in sequential mode. A simultaneous mode is something that we’re working with the software team to implement.

What would the cartridge cost be long-term?

MM: Cartridge cost long-term is going to be on par with most of our competitors. However, our whole system is going to depend on which bundle you use. The whole system, the start-up system with some cartridges is going to come in around $10,000 or lower. The cartridges with four channels that you can reuse after you validate, will come in somewhere under $70.

Can any aqueous solution be used and is the accuracy affected by any solution components such as high protein concentration or detergents?

SM: You can use deionized (DI) water, phosphate-buffered saline (PBS), and other aqueous solutions with surfactant. It doesn't seem to be affected by the components that are in there. Detergents like surfactants are actually great for this. They help with aqueous dispensing. For high protein concentrations, I think you are going to need to test how high you can go, so that's probably going to be user dependent.

How much does the overall system cost?

MM: The total system, depending on which bundle you get, is going to come in significantly lower than our competitors, at probably around $10,000 or lower.

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