How to use the Dragonfly
The Dragonfly liquid handler (http://ttplabtech.com/liquid-handling/dragonfly_screen_optimization/) uses positive displacement pipetting with disposable tips to set up custom crystallisation screens from stock solutions (optimisation screens). Please request training from the facility manager before using this instrument. Running an experiment on Dragonfly takes between 5 and 15 minutes depending on the complexity of the custom screen. There is therefore no booking system for Dragonfly. Consumables for Dragonfly (tips, inserts, reservoirs and MXOne mixer pin arrays) can be ordered via Sharepoint, and James Mansfield and/or Marc Morgan will take the requested consumables out for you and put them in a bag on the shelf above the Dragonfly laptop in 022 SECB.
Before the experiment
As Dragonfly formulates crystallisation screens from user-defined stock solutions, a number of strict rules regarding chemical handling need to be respected. Users who do not follow these instructions will be denied access to the Dragonfly. The rules are as follows:
- The use of cacodylate-based buffer solutions is strictly prohibited. If you need to use a buffer in the same pH range as sodium cacodylate please use MES.
- Please use PPE (gloves, labcoat etc) when handling chemical solutions. Nitrile gloves are available in the laboratory.
- Any stock solution presenting an inhalation hazard will need to be cleared by the facility manager before use on Dragonfly.
- Please bring minimal amounts of stock solutions to the laboratory for Dragonfly use. Typically for a 3-component screen on a 96-well crystallisation plate, total stock solutions needed shouldn’t exceed 10ml. If you need to use more than 50ml of stock solutions (excluding water) please let the facility manager beforehand.
- Please retrieve all stock solutions when finished. Do not pour excess stock solutions down the sink (except water). Excess stock solutions in Dragonfly reservoirs should be poured back into your tubes. There is no risk of cross-contamination between different solutions in reservoirs on Dragonfly.
- It is the user’s responsibility to deal with spillages and keep the area around Dragonfly clean and safe for the next user.
Design your optimisation screen using the DFDesigner software. DFDesigner software is freely available to all users with a Windows 7 (or above) computer. The software is very easy to use and although it will be covered in your initial training session, design your screen a few days in advance to ensure you have the correct settings. Marc Morgan can be contacted with any questions you have on screen design. DFDesigner software has also been installed on the Mosquito laptop and Leica microscope computer in the facility.
The disposable tips have a maximum fill volume of 4ml so if this is exceeded for one or more components of your screen, a warning will alert you to this. If this is the case you can select the “split between tips” option to dispense stock solution from 2 (or more) tips.
Dragonfly accepts a number of different plates for performing your optimisations in:
- MRC 2-well
- SwissCi SD-3
- Greiner CrystalQuick triple well
- Greiner CrystalQuick X
- Greiner 96
- Corning CrystalEX
- Corning CrystalEX second generation
- TTP IQ
- TTP 96
- Robbins Intelliplate
- Qiagen (Nextal) EasyXtal 15
- Axygen 1ml 96 deep well
- MRC Maxi
- Corning 96
Please note that VDX24 well and Linbro 24 well plates cannot be used on Dragonfly.
Export your screen for use on Dragonfly.
Ensure you have selected the correct format of wells (rows by columns) and well volume in DFDesigner before exporting your screen. Export your optimisation screen as a csv file (save in the optimisations folder), and also as a DFY settings file. There is also an option to export as a pdf for a comprehensive record of your screen.
Running your experiment
Turn on the instrument and wait 15 seconds before launching the Dragonfly software on the laptop. If this lag hasn’t been respected, or the instrument is not turned on, the software will run in simulation mode. Import your csv into the Dragonfly software and ensure the correct plate and well number have been selected for your experiment. Load the disposable tips (with insert!) onto the Dragonfly according to the diagram shown on screen. If the tip has successfully been loaded, a little green box appears on screen for that location.
Next load your reservoirs into the Dragonfly tray and add your stock solutions to the reservoirs. The reservoirs have 2 lines indicating 5 and 10 ml fill volumes. The minimum volume allowed in a reservoir is 0.5ml. Load your chosen plate type into the Dragonfly plate holder.
Select Aspirate and the Dragonfly will prime the inserts into the tips and then aspirate up the stock solutions needed for your screen. Then hit Run and your screen will begin dispensing.
After your experiment
Very important – DO NOT TAKE OUT THE DISPOSABLE TIPS BEFORE HITTING THE “REMOVE” BUTTON
“Remove” purges the excess solution in the tips back into the reservoirs and then takes the rods out of the tips for safe removal. If the rods are still in the tips then you risk damaging the instrument when taking out the tips.
To dispose of unwanted stock solutions please do not pour them down the sink. Excess stock solutions should be poured back into their original container and disposed of at user’s leisure in their laboratory space. Please clear up any spillages and dispose of any unwanted Dragonfly consumables in the orange bin provided.