Frequently Asked Questions

What are the major differences between the DropArray plate and a conventional microplate?

Rather than using physical wells, DropArray has a hydrophobic coating covering the entire area of a flat surface except for a series of hydrophillic spots. These spots form an array that conforms to the well layout of the ANSI/SBS 4-2004 standard. Using standard microplate pipetting devices, liquid dispensed on these spots form droplets that remain in a fixed position, even when the plate is shaken or inverted. Plastic walls surround the entire flat surface, which serves to contain washing buffers that are added in bulk to the plate. Unlike a standard microplate that requires dispensing and aspiration from each well, DropArray plates add or remove bulk liquids like washing buffers to the entire plate at once. This enables liquids to be added or removed at very low velocities compared to using a traditional pipette. By reducing turbulence in these wash steps, far fewer cells are lost from the assay droplets, even with suspension cells. Evaporation is controlled by using Curiox’ Liquid Lid sealing fluid. This special fluid, which is added and removed in the same manner as wash buffer, eliminates assay droplet evaporation yet ensures good gas exchange for multi-day assays.

What are the distinct advantages?

DropArray enables convenient low volume cell-based assays in the range of 2 – 4 microliters (384 well format) or 8 – 12 microliters (96 well format). Alternative low volume plates require special washing systems, which still disrupt cells far more than the DropArray system due to the high velocity of liquid leaving or entering a pipette tip.

Do we need any specialized dispenser or imaging systems?

DropArray allows seamless use on any conventional dispenser, gripper, stacker, reader or imager.

What are the cell growth parameters on a 384-well DropArray plate?

The DropArray plate can perform with a low confluence of 80 cells per mm2 to a very high confluence of 630 cells per mm2. For first time users, we recommend 250 cells per mm2. The cell growth rate on DropArray plate is no different compared to a conventional microplate.

Can cells grow under the layer of DropArray Liquid Lid?

The Liquid Lid fluid is highly gas-permeable and allows gaseous exchange for optimal cell growth.

How is the Liquid Lid added without disturbing the assay droplets?

The Liquid Lid is a proprietary mixture of perfluorocarbon liquids with a viscosity similar to water. It is added slowly to the DropArray plate, which prevents assay droplets from being disturbed or dislodged. When the Liquid Lid is poured off the plate, any residual Liquid Lid evaporates.

Is the DropArray Liquid Lid recyclable?

Liquid Lid can be recycled by filtering with a 0.22 micron or a 0.45 micron pore size filter system, and/or optionally autoclaved with conventional laboratory glassware.

How long can the cells survive on DropArray plates? How do I perform media exchange?

Depending on cell-line and assay requirements, cells can survive up to 2 weeks without media exchange. Media can be aspirated manually or washed off using DropArray HT/LT Washing Stations before applying fresh media.

Do the plates come coated?

DropArray plates are tissue culture compatible. DropArray plates can be easily coated with DNA, poly-lysine, Collagen, fibronectin, silane-compatible substrates, or any other cell culture coatings.

How much wash buffer and washing time needed to wash plates on the DropArray HT/LT Washing Station?

Typical use is 110 ml for a 1x washing step, ~ 2 minutes, and 330 ml for a 3x washing step, which takes a total of 5 minutes.

Will air bubbles be introduced during the washing process?

The introduction of bulk wash buffer over the flat DropArray slide discourages air bubbles to interfere with the washing of the reacting surfaces.

Is it possible to remove air bubbles introduced during dispensing into the ”wells”?

The use of the proprietary DropArray Liquid Lid removes any air bubbles present.

Can we dispense unto the DropArray plate through the Liquid Lid?

Yes, contact dispensing and non-contact dispensing from your dispenser can be achieved in the presence of an optimized volume of Liquid Lid.

How is cross-contamination between assay droplets prevented?

DropArray plates have a pitch distance between each hydrophilic spot conforming to the SBS/ANSI standard, which is sufficient to prevent adjacent droplets from touching. DropArray Liquid Lid maintains the hydrophobic pattern between wells and prevents evaporation of the droplets. During the wash process, the HT/LT Washing Station first adds 80 ml of wash buffer and then gently rocks the plate, avoiding the turbulence and high velocity liquid exchange of traditional washers.

What is a typical assay run time compared to a conventional assay?

A 5-step cell-immunostaining assay with a short incubation typically takes 2.5 hours.

Is the DropArray HT/LT Washing Station automation-friendly?

The DropArray HT Washing Station HT200 has a PC-HT200 RS232C port for communication with automation controllers.

What is the Baud Rate and Data bits for the PC-HT200 RS232C?

Baud rate = 9600 and Data bits = 8.